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Sample records for gd dy ho

  1. Complex magnetism of Ho-Dy-Y-Gd-Tb hexagonal high-entropy alloy

    Science.gov (United States)

    Lužnik, J.; Koželj, P.; Vrtnik, S.; Jelen, A.; Jagličić, Z.; Meden, A.; Feuerbacher, M.; Dolinšek, J.

    2015-12-01

    Rare earth based equimolar Ho-Dy-Y-Gd-Tb hexagonal high-entropy alloy (HEA) is a prototype of an ideal HEA, stabilized by the entropy of mixing at any temperature with random mixing of elements on the hexagonal close-packed lattice. In order to determine intrinsic properties of an ideal HEA characterized by the enormous chemical (substitutional) disorder on a weakly distorted simple lattice, we have performed measurements of its magnetic and electrical response and the specific heat. The results show that the Ho-Dy-Y-Gd-Tb hexagonal HEA exhibits a rich and complex magnetic field-temperature (H ,T ) phase diagram, as a result of competition among the periodic potential arising from the electronic band structure that favors periodic magnetic ordering, the disorder-induced local random potential that favors spin glass-type spin freezing in random directions, the Zeeman interaction with the external field that favors spin alignment along the field direction, and the thermal agitation that opposes any spin ordering. Three characteristic temperature regions were identified in the (H ,T ) phase diagram between room temperature and 2 K. Within the upper temperature region I (roughly between 300 and 75 K), thermal fluctuations average out the effect of local random pinning potential and the spin system behaves as a pure system of compositionally averaged spins, undergoing a thermodynamic phase transition to a long-range ordered helical antiferromagnetic state at the Néel temperature TN=180 K that is a compositional average of the Néel temperatures of pure Tb, Dy, and Ho metals. Region II (between 75 and 20 K) is an intermediate region where the long-range periodic spin order "melts" and the random ordering of spins in the local random potential starts to prevail. Within the low-temperature region III (below 20 K), the spins gradually freeze in a spin glass configuration. The spin glass phase appears to be specific to the rare earths containing hexagonal HEAs, sharing

  2. Electronic structure and 3d-4f exchange interactions in zircon-type RCrO{sub 4} oxides (R=Dy, Ho and Gd)

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    Ray, Avijeet, E-mail: avijeet.ray04@gmail.com; Maitra, Tulika [Department of Physics, Indian Institute of Technology, Roorke, Roorkee – 247667, Uttarakhand (India)

    2015-06-24

    Using first principles density functional theory (DFT) calculations within GGA and GGA+U approximations we studied both ferromagnetic (FM) and antiferromagnetic (AFM) phases of zircon type RCrO{sub 4} (R= Dy, Ho, Gd) oxides. We estimated and compared the 3d-4f exchange interaction strengths J between the nearest neighbor R{sup 3+} and Cr{sup 5+} ions for R=Dy, Gd. Our results predict that DyCrO{sub 4}, GdCrO{sub 4} and HoCrO{sub 4} have ferromagnetic ground state which is consistent with experimental observations.

  3. Estimation on Magnetic Refrigeration Material (Gd1-xREx)5Si4(RE=Dy,Ho)

    Institute of Scientific and Technical Information of China (English)

    Wei WU; Zai FENG; Lijun GUO

    2006-01-01

    A systematic (Gd1-xREx)5Si4 (RE=Dy, Ho) alloys are investigated to estimate their magnetocaloric effect.The Curie points of (Gd1-xREx)Si4 alloys can tunable from 266 K to 336 K when RE=Dy, Ho; x=0~0.35 and 0~0.15, respectively, and decrease nearly linearly with increasing x. These alloys keep orthorhombic structures Ge5Sm4 and exhibit second order transition when they experience in a change magnetic field at about Curie when magnetic field changes 0~2 T. The adiabatic temperatures changes (△Tad) of these alloys at Curie points are larger than 1 K in a field change 0~1.4 T, the curve of △Tad is wide as that of Gd. The relative cooling power is about 0.8~0.9 J/cm3 when field changes 0~2 T, 55% of that of Gd. Comparing with Gd5(Si1-xGex)4, these alloys do not contain expensive element Ge, so that their cost are lower than the former. Because they could work at temperature region 260~340 K due to their Curie points can be tuned, which is an advantage comparing with Gd, these alloys are potential magnetic refrigerants working in a magnetic refrigerator with a low magnetic field at room temperatures.

  4. Magnetic properties of R/sub 3/Rh/sub 2/ compounds with R = Gd, Tb, Dy, Ho and Er

    Energy Technology Data Exchange (ETDEWEB)

    Gignoux, D. (Centre National de la Recherche Scientifique, 38 - Grenoble (France). Lab. Louis Neel); Gomez-Sal, J.C.; Aramburu-Zabala, J.A. (Santander Univ. (Spain). Facultad de Ciencias); Paccard, D. (Universite de Savoie, 74 - Annecy-le-Vieux (France). Lab. Structure de la Matiere)

    1984-04-01

    Bulk magnetic measurements performed on polycrystalline samples of the tetragonal compounds R/sub 3/Rh/sub 2/ with R = Gd, Tb, Dy, Ho and Er are presented. All the compounds are ferromagnetic at low temperature. However in Tb/sub 3/Rh/sub 2/ an antiferromagnetic behaviour is observed between 14 and 24 K. In Gd/sub 3/Rh/sub 2/, where the magnetocrystalline anisotropy must be negligible, it seems that the magnetic structure is not collinear. In the other compounds the observed properties essentially result from indirect exchange interactions and crystal field effects acting on the rare earth ions which lie in low symmetry sites.

  5. Ionic Transport Properties in Nanocrystalline Ce0.8A0.2O2-δ (with A = Eu, Gd, Dy, and Ho) Materials.

    Science.gov (United States)

    Baral, Ashok Kumar; Sankaranarayanan, V

    2010-01-30

    The ionic transport properties of nanocrystalline 20 mol% Eu, Gd, Dy, and Ho doped cerias, with average grain size of around 14 nm were studied by correlating electrical, dielectric properties, and various dynamic parameters. Gd-doped nanocrystalline ceria shows higher value of conductivity (i.e., 1.8 × 10-4 S cm-1 at 550°C) and a lower value of association energy of oxygen vacancies with trivalent dopants Gd3+ (i.e., 0.1 eV), compared to others. Mainly the lattice parameters and dielectric constants (ε∞) are found to control the association energy of oxygen vacancies in these nanomaterials, which in turn resulted in the presence of grain and grain boundary conductivity in Gd- and Eu-doped cerias and only significant grain interior conductivity in Dy- and Ho-doped cerias.

  6. Theoretical investigations on magnetic entropy change in amorphous and crystalline systems: Applications to RAg (R=Tb, Dy, Ho) and GdCuAl

    Energy Technology Data Exchange (ETDEWEB)

    Ranke, P.J. von, E-mail: von.ranke@uol.com.br [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Nóbrega, E.P. [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Caldas, A. [Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro, RJ (Brazil); Alho, B.P. [Instituto de Aplicação Fernando Rodrigues da Silveira, Universidade do Estado do Rio de Janeiro, Rua Santa Alexandrina, 288, 20260-232 RJ (Brazil); Ribeiro, P.O.; Alvarenga, T.S.T.; Lopes, P.H.O.; Sousa, V.S.R. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Carvalho, A. Magnus G. [Laboratório Nacional de Luz Síncrotron, CNPEM, 13083-970 Campinas, SP (Brazil); Oliveira, N.A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil)

    2014-11-15

    We report theoretical investigations on the magnetic entropy changes in amorphous systems through two different assumptions. In the first assumption, the HPZ-anisotropic model is considered to deal with the random direction of magnetic moments, where the amorphous RAg (R=Tb, Dy and Ho) were used as prototypes systems. In the second assumption, the amorphisation is parameterized through the exchange interaction distribution and GdCuAl, in amorphous and crystalline structures, were considered as prototypes systems. Comparisons between the magnetic entropy changes under amorphisation and under the usual magnetic field variation were performed. The model reveals the dependence of refrigerant capacity on the amorphisation parameter, and an optimum amorphisation parameter was calculated. - Highlights: • Theoretical investigation on RAg (R=Tb, Dy and Ho) and GdCuAl amorphous alloys. • Magnetic entropy changes in GdCuAl in both amorphous and crystalline structures. • The refrigerant capacity was compared in both amorphous and crystalline phases.

  7. Strong paramagnetic crystalline LnVO{sub 4} (Ln: Gd, Tb, Dy, Ho, Er) nanoparticles synthesized by a fabricating method

    Energy Technology Data Exchange (ETDEWEB)

    Bulbul, Berna; Beyaz, Seda, E-mail: sedacan@balikesir.edu.tr

    2016-04-15

    Strong paramagnetic lanthanide orthovanadate (LnVO{sub 4}, Ln: Gd, Tb, Dy, Ho, Er) nanoparticles were synthesized under ambient conditions by a novel precipitation method that is economical and fabricating. To the X-ray diffraction patterns, all samples are well-crystallized zircon type orthovanadate and have pure tetragonal phase. Their crystal sizes increased from 12.58 to 15.12 nm with increasing the ionic radii of lanthanide. As confirmed with the surface observation by a transmission electron microscope, it was identified that their two-dimensional projection is an ellipse with the two major axes. It was seen that the sizes of nanoparticles (14.40nm-70.69 nm) were bigger than the crystal sizes because of their polycrystalline structures. Besides, the particle sizes increased with reduction of ionic radii of lanthanide. The magnetic properties obtained from a vibrating sample magnetometer revealed that all nanoparticles are strong paramagnetic at room temperature showing an increase in molar susceptibility up to 4.79 × 10{sup −1} cm{sup 3} mol{sup −1}. Such highly crystalline, small and paramagnetic nanoparticles could be thought to be convenient for biomedical applications. - Highlights: • A general fabricating method for lanthanide orthovanadate nanoparticles is proposed. • The method generates highly small and crystalline nanoparticles. • The reduction in ionic radius of lanthanide (Ln{sup 3+}) causes to increase particle size.

  8. Electron-magnon interaction in RNiBC (R=Er, Ho, Dy, Tb, and Gd) series of compounds based on magnetoresistance measurements

    Science.gov (United States)

    Fontes, M. B.; Trochez, J. C.; Giordanengo, B.; Bud'ko, S. L.; Sanchez, D. R.; Baggio-Saitovitch, E. M.; Continentino, M. A.

    1999-09-01

    We present a study of the transport and magnetic properties of a series of RNiBC compounds (R=Er, Ho, Dy, Tb, and Gd). All the materials investigated have long range magnetic order at sufficiently low temperatures. Magnetoresistance measurements are presented for a large range of temperatures (T) and magnetic fields (H). We show that below the critical temperature, the temperature dependence of the resistivity is determined by electron scattering due to the elementary excitations (spin waves) of the ordered magnetic phase and the values of the gap in the magnon spectra were derived. Finally we discuss the H×T phase diagram of these materials.

  9. Family of defect-dicubane Ni4Ln2 (Ln = Gd, Tb, Dy, Ho) and Ni4Y2 complexes: rare Tb(III) and Ho(III) examples showing SMM behavior.

    Science.gov (United States)

    Zhao, Lang; Wu, Jianfeng; Ke, Hongshan; Tang, Jinkui

    2014-04-07

    Reactions of Ln(III) perchlorate (Ln = Gd, Tb, Dy, and Ho), NiCl2·6H2O, and a polydentate Schiff base resulted in the assembly of novel isostructural hexanuclear Ni4Ln2 complexes [Ln = Gd (1), Tb (2), Dy (3), Ho (4)] with an unprecedented 3d-4f metal topology consisting of two defect-dicubane units. The corresponding Ni4Y2 (5) complex containing diamagnetic Y(III) atoms was also isolated to assist the magnetic studies. Interestingly, complexes 2 and 3 exhibit SMM characteristics and 4 shows slow relaxation of the magnetization. The absence of frequency-dependent in-phase and out-of-phase signals for the Ni-Y species suggests that the Ln ions' contribution to the slow relaxation must be effectual as previously observed in other Ni-Dy samples. However, the observation of χ″ signals with zero dc field for the Ni-Tb and Ni-Ho derivatives is notable. Indeed, this is the first time that such a behavior is observed in the Ni-Tb and Ni-Ho complexes.

  10. The interplay between magnetism and superconductivity in RNi 2B 2C (R dbnd Lu, Tm, Er, Ho, Dy, Tb, Gd)

    Science.gov (United States)

    El Massalami, M.; Bud'ko, S. L.; Giordanengo, B.; Baggio-Saitovitch, E. M.

    1995-02-01

    The superconducting and magnetic phase diagram (characteristic temperatures versus effective ionic radii) of the RNi 2B 2C (R dbnd Lu, Tm, Er, Ho, Dy, Tb, Gd) compounds are considered. Although the gradual degradation of superconductivity can be scaled to the de Gennes factor, ( g-1) 2J( J + 1), the unique reentrant behavior of the HoNi 2B 2C compound and the abrupt quenching of superconductivity for R lighter than Ho are most probably unaccountable within this scheme. Rather, it is argued that their low- T magnetic and transport properties as well as the main features of the interplay between magnetism and superconductivity can be accounted for if the low- T magnetism of HoNi 2B 2C, as reported by Grigereit et al., is generalized to the other isomorphous R members. Thus the onset of the 4f moments antiferromagnetic state at T1 is accompanied by an oscillatory component, which transforms to a commensurate antiferromagnetic state at T2. For HoNi 2B 2C, the pressure and magnetic-field influence on Tc, T1 and T2 will be discussed.

  11. Pico- and subpicosecond relaxation processes in lanthanide-porphyrin complexes. [Lanthanoids: Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu

    Energy Technology Data Exchange (ETDEWEB)

    Solov' ev, K.N.; Tsvirko, M.P.; Krasauskas, V.V.; Pyatosin, V.E.; Stel' makh, G.F.

    1984-03-01

    Methods of nano- and picosecond absorption spectroscopy and luminescence are used to determine the deactivation rates of ..pi.., ..pi..*-electron states of S/sub 2/, S/sub 1/ and T/sub 1/ in complexes of organic molecules of meso-tetratolylporphyne and tetrabenzoporphyne with trivalent Sm/sup 3 +/, Eu/sup 3 +/, Gd/sup 3 +/, Tb/sup 3 +/, Dy/sup 3 +/, Ho/sup 3 +/, Er/sup 3 +/, Tm/sup 3 +/, Yb/sup 3 +/, Lu/sup 3 +/. Quantitative data on superfast relaxation processes in lanthanide porphyrines are obtained. The function of the metal entral ion is presented in details as the excitation factor in deactivation processes of photoexcitation energy of the systems in question.

  12. New Materials Derived from Ybco: CrSr2RECu2O8 (RE = La, Pr, Nd, Eu, Gd, Tb, Dy, Y, Ho, Er, Lu).

    Science.gov (United States)

    Ruiz-Bustos, Rocío; Aguirre, Myriam H; Alario-Franco, Miguel A

    2005-05-02

    Eleven new oxides, derived from yttrium barium copper oxide by replacing the square-planar copper [Cu-O4] of the basal plane of the triple perovskite-based structure with octahedral Cr(IV), have been prepared at high pressure and temperature. Their crystal structures have been determined, and their complex microstructure has been established by means of high-resolution electron microscopy and electron diffraction. The materials have a general formula of CrSr2RECu2O8 (RE = La, Pr, Nd, Eu, Gd, Tb, Dy, Y, Ho, Er, and Lu); they are tetragonal, show the symmetry of space group P4/mmm, and do not appear to be superconducting.

  13. Structural and magnetic properties of two branches of the tripod-kagome-lattice family A2R3Sb3O14 (A = Mg, Zn; R = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb)

    Science.gov (United States)

    Dun, Z. L.; Trinh, J.; Lee, M.; Choi, E. S.; Li, K.; Hu, Y. F.; Wang, Y. X.; Blanc, N.; Ramirez, A. P.; Zhou, H. D.

    2017-03-01

    We present a systematic study of the structural and magnetic properties of two branches of the rare-earth tripod-kagome-lattice (TKL) family A2R3Sb3O14 (A = Mg, Zn; R = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb; here, we use abbreviation A-R, as in MgPr for Mg2Pr3Sb3O14 ), which complements our previously reported work on MgDy, MgGd, and MgEr [Z. L. Dun et al., Phys. Rev. Lett. 116, 157201 (2016), 10.1103/PhysRevLett.116.157201]. The present susceptibility (χdc, χac) and specific-heat measurements reveal various magnetic ground states, including the nonmagnetic singlet state for MgPr, ZnPr; long-range orderings (LROs) for MgGd, ZnGd, MgNd, ZnNd, and MgYb; a long-range magnetic charge ordered state for MgDy, ZnDy, and potentially for MgHo; possible spin-glass states for ZnEr, ZnHo; the absence of spin ordering down to 80 mK for MgEr, MgTb, ZnTb, and ZnYb compounds. The ground states observed here bear both similarities as well as striking differences from the states found in the parent pyrochlore systems. In particular, while the TKLs display a greater tendency towards LRO, the lack of LRO in MgHo, MgTb, and ZnTb can be viewed from the standpoint of a balance among spin-spin interactions, anisotropies, and non-Kramers nature of single-ion state. While substituting Zn for Mg changes the chemical pressure, and subtly modifies the interaction energies for compounds with larger R ions, this substitution introduces structural disorder and modifies the ground states for compounds with smaller R ions (Ho, Er, Yb).

  14. Magnetic hyperfine interactions on Cd sites of the rare-earth cadmium compounds R Cd (R =Ce , Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er)

    Science.gov (United States)

    Cavalcante, F. H. M.; Leite Neto, O. F. L. S.; Saitovitch, H.; Cavalcante, J. T. P. D.; Carbonari, A. W.; Saxena, R. N.; Bosch-Santos, B.; Pereira, L. F. D.; Mestnik-Filho, J.; Forker, M.

    2016-08-01

    This paper reports the investigation of the magnetic hyperfine field Bh f in a series of rare-earth (R ) cadmium intermetallic compounds R Cd and GdCd2 measured by perturbed angular correlation (PAC) spectroscopy using 111In/111Cd as probe nuclei at Cd sites as well as first-principles calculations of Bh f at Cd sites in the studied compounds. Vapor-solid state reaction of R metals with Cd vapor and the 111In radioisotope was found to be an appropriate route of doping rare-earth cadmium compounds with the PAC probe 111In/111Cd. The observation that the hyperfine parameters depend on details of the sample preparation provides information on the phase preference of diffusing 111In in the rare-earth cadmium phase system. The 111Cd hyperfine field has been determined in the compounds R Cd for the R constituents Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er, in several cases as a function of temperature. For most R constituents, the temperature dependence Bh f(T ) of 111Cd:R Cd is consistent with ferromagnetic order of the compound. DyCd, however, presents a remarkable anomaly: a finite magnetic hyperfine field is observed only in the temperature interval 35 K ≤ T ≤ 80 K which indicates a transition from ferromagnetic order to a spin arrangement where all 4 f -induced contributions to the magnetic hyperfine field at the Cd site cancel. First-principles calculation results for DyCd show that the (π , π , 0) antiferromagnetic configuration is energetically more favorable than the ferromagnetic. The approach used in the calculations to simulate the R Cd system successfully reproduces the experimental values of Bh f at Cd sites and shows that the main contribution to Bh f comes from the valence electron polarization. The de Gennes plot of the hyperfine field Bh f of 111Cd:R Cd vs the 4 f -spin projection (g -1 )J reflects a decrease of the strength of indirect 4 f -4 f exchange across the R series. Possible mechanisms are discussed and the experimental results indicate that

  15. Rotational and translational distortions of the crystal structure of the Sr{sub 2}HrRuO{sub 6} (Hr = Ho, Dy, Gd, Eu) complex perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Triana, C.A., E-mail: ctrianae@unal.edu.co [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá D.C. (Colombia); Landínez Téllez, D.A. [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá D.C. (Colombia); Roa-Rojas, J., E-mail: jroar@unal.edu.co [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá D.C. (Colombia)

    2013-05-15

    Sr{sub 2}HrRuO{sub 6} (Hr = Ho, Dy, Gd, Eu) complex perovskites were synthesized through the high-temperature solid-state reaction method, and their crystal structures were analyzed in detail as a function of the Hr-cation ionic radius. Results of powder XRD pattern measurement and Rietveld analysis of the experimental profiles show that the Sr{sub 2}HrRuO{sub 6} compounds crystallize in a monoclinic distorted perovskite-like structure, P2{sub 1}/n (#14) space group, where the unit cell parameters are related to the primitive unit cell a{sub p} by a≈√(2)a{sub p}, b≈√(2)a{sub p} and c ≈ 2a{sub p}. The structures show an alternate distribution of the Ru{sup 5+} (2d: 0.5, 0, 0) and Hr{sup 3+} (2c: 0, 0.5, 0) making up RuO{sub 6} and HrO{sub 6} octahedra alternatively arranged in two interleaving fcc sublattices, where the O(1), O(2), and O(3) ions are localized at the corner of the octahedral, while the Sr{sup 2+} is located at the A-site, occupying the cavities built by the corner-sharing octahedra with Wyckoff position 4e. Due to the existence of mismatched ionic sizes between the ionic radii of the Sr{sub 2}HrRuO{sub 6} compounds, the HrO{sub 6} and RuO{sub 6} octahedra are constrained to tilting around the [111]{sub c}, [001]{sub c}, and [110]{sub c} cubic directions so as to optimize the Sr–O inter-atomic bond lengths, tending to rotate the structure in order to fix the Ru{sup 5+} and Hr{sup 3+} ions on the M′ and M″ sites of the complex perovskites. The cell parameters a, b, and c, the inter-atomic bond angles, the inter-atomic bond lengths, and the tilting angles increase as the Hr-cation ionic radius increases. The mismatch that exists in the Sr{sub 2}HrRuO{sub 6} ionic radius produces a large distortion from the ideal cubic symmetry. The pure perovskite-like phase of Sr{sub 2}HrRuO{sub 6} is thermodynamically and kinetically stable at high temperatures above 1420 K, where it is entirely governed by the average size of the Hr{sup 3+} and Ru

  16. Structural Study of a Doubly Ordered Perovskite Family NaLnCoWO6 (Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb): Hybrid Improper Ferroelectricity in Nine New Members.

    Science.gov (United States)

    Zuo, Peng; Colin, Claire V; Klein, Holger; Bordet, Pierre; Suard, Emmanuelle; Elkaim, Erik; Darie, Céline

    2017-07-17

    The compounds of the doubly ordered perovskite family NaLnCoWO6 (Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb) were synthesized by solid-state reaction, nine of which (Ln = Y, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb) are new phases prepared under high-temperature and high-pressure conditions. Their structural properties were investigated at room temperature by synchrotron X-ray powder diffraction and neutron powder diffraction. All of them crystallize in monoclinic structures, especially the nine new compounds have the polar space group P21 symmetry, as confirmed by second harmonic generation measurements. The P21 polar structures were decomposed and refined in terms of symmetry modes, demonstrating that the polar mode is induced by two nonpolar modes in a manner of Hybrid Improper Ferroelectricity. The amplitudes of these three major modes all increase with decreasing the Ln cation size. The spontaneous ferroelectric polarization is estimated from the neutron diffraction data of three samples (Ln = Y, Tb, and Ho) and can be as large as ∼20 μC/cm(2).

  17. Sensitivity of magnetic properties to chemical pressure in lanthanide garnets Ln 3 A 2 X 3O12, Ln  =  Gd, Tb, Dy, Ho, A  =  Ga, Sc, In, Te, X  =  Ga, Al, Li

    Science.gov (United States)

    Mukherjee, P.; Sackville Hamilton, A. C.; Glass, H. F. J.; Dutton, S. E.

    2017-10-01

    A systematic study of the structural and magnetic properties of three-dimensionally frustrated lanthanide garnets Ln 3 A 2 X 3O12, Ln  =  Gd, Tb, Dy, Ho, A  =  Ga, Sc, In, Te, X  =  Ga, Al, Li is presented. Garnets with Ln  =  Gd show magnetic behaviour consistent with isotropic Gd3+ spins; no magnetic ordering is observed for T  ⩾  0.4 K. Magnetic ordering features are seen for garnets with Ln  =  Tb, Dy, Ho in the temperature range 0.4  Tb, Dy, Ho.

  18. Study of hyperfine interactions in intermetallic compounds Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In; Estudo de interacoes hiperfinas em compostos intermetalicos Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In e Ho(Ni,Pd)In

    Energy Technology Data Exchange (ETDEWEB)

    Lapolli, Andre Luis

    2006-07-01

    Systematic behavior of magnetic hyperfine field (B{sub hf}) in the intermetallic compounds Gd(Ni,Pd,Cu)In Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In was studied by Perturbed Gamma-Gamma Angular Correlation spectroscopy. The measurements of B{sub hf} were carried out at the rare earth atom and in sites using the nuclear probes {sup 140}Ce and {sup 11}'1Cd respectively. The variation of hyperfine field with temperature, in most cases, follows the Brillouin function predicted from the molecular field theory. The hyperfine field values at rare earth atom sites obtained from {sup 140}Ce probe as well as at in sites obtained from {sup 111}Cd probe for each series of compounds were extrapolated to zero Kelvin B{sub hf}(T=0) from these curves. These values were compared with the values of the literature for other compounds containing the same rare earth element and all of them show a linear relationship with the ordering temperature. This indicates that the main contribution to B{sub hf} comes from the conduction electron polarization (CEP) through Fermi contact interaction and the principal mechanism of magnetic interaction in these compounds can be described by the RKKY type interaction. The values of B{sub hf}(T=0) for each family of intermetallic compounds RNiIn and RPdIn when plotted as a function of 4f spin projection of rare earth element also shows a linear relationship. Exceptions are the results for the compounds RNiIn obtained with {sup 111}Cd probe where a small deviation from linearity is observed. The results of the measurements carried out with the {sup 111}Cd probe were also analyzed to obtain the hyperfine parameters of the quadrupole interaction as a function of temperature for RPdln and GdNiIn compounds. The results show that for the compound GdPdIn there might be some Gd-In disorder at high temperature. (author)

  19. Heat capacity, entropy of Ln2(MoO4)3 (Ln = La, Sm, and Gd), and the high-temperature enthalpy of Ln2(MoO4)3 (Ln = Eu, Dy, and Ho)

    Science.gov (United States)

    Lazarev, V. M.; Suponitskiy, Y. L.; Liashenko, S. E.

    2016-05-01

    The low-temperature heat capacity of Ln2(MoO4)3 (Ln = La, Sm, and Gd) is investigated by means of adiabatic calorimetry within the range of 60-300 K. The temperature dependences of the heat capacity are found and the values of the standard entropy are calculated, based on extrapolations to 0 K. Characteristic temperatures for molybdates are determined from the results of IR spectroscopic studies. The high-temperature enthalpy of Ln2(MoO4)3 (Ln = Eu, Dy, and Ho) is measured via high-temperature microcalorimetry, and the temperature dependence of heat capacity is calculated in the range of 298-1000 K. Since samarium and gadolinium molybdates are of the same structural type as terbium molybdate, we can estimate the anomaly of the heat capacity in the low-temperature region using the data for terbium molybdate and find the entropy of samarium and gadolinium molybdates.

  20. Crystal structures of the R{sub 2}Pb{sub 3}Sn{sub 3}S{sub 12} (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gulay, L.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Avenue 13, 43009 Lutsk (Ukraine)], E-mail: gulay@univer.lutsk.ua; Ruda, I.P. [Department of General and Inorganic Chemistry, Volyn State University, Voli Avenue 13, 43009 Lutsk (Ukraine); Marchuk, O.V. [Department of Physical and Colloidal Chemistry, Volyn State University, Voli Avenue 13, 43009 Lutsk (Ukraine); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Avenue 13, 43009 Lutsk (Ukraine)

    2008-06-12

    The crystal structures of the R{sub 2}Pb{sub 3}Sn{sub 3}S{sub 12} (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm) compounds (space group Pmc2{sub 1}, Pearson symbol oP40, a = 0.38992 (1) nm, b = 2.01175 (7) nm, c = 1.15140 (4) nm, R{sub I} 0.0785 for Ho{sub 2}Pb{sub 3}Sn{sub 3}S{sub 12}) were investigated using X-ray powder diffraction. The R{sub 1} atoms are surrounded by trigonal prisms with two additional atoms, the R{sub 2} atoms by distorted octahedra with one additional atom. The Pb{sub 1} and Pb{sub 3} atoms are surrounded by trigonal prisms with one additional atom, the Pb{sub 2} atoms by trigonal prisms with two additional atoms. Octahedral surrounding exists for Sn{sub 1} and Sn{sub 2}. The Sn{sub 3} atoms are located in trigonal bipyramids. Four or five neighbours surround the S atoms.

  1. Tetranuclear hetero-metal [Co(II)2Ln(III)2] (Ln = Gd, Tb, Dy, Ho, La) complexes involving carboxylato bridges in a rare μ4-η(2):η(2) mode: synthesis, crystal structures, and magnetic properties.

    Science.gov (United States)

    Abtab, Sk Md Towsif; Majee, Mithun Chandra; Maity, Manoranjan; Titiš, Ján; Boča, Roman; Chaudhury, Muktimoy

    2014-02-01

    A new family of 3d-4f heterometal 2 × 2 complexes [Co(II)2(L)2(PhCOO)2Ln(III)2(hfac)4] (1-5) (Ln = Gd (compound 1), Tb (compound 2), Dy (compound 3), Ho (compound 4), and La (compound 5)) have been synthesized in moderate yields (48-63%) following a single-pot protocol using stoichiometric amounts (1:1 mol ratio) of [Co(II)(H2L)(PhCOO)2] (H2L = N,N'-dimethyl-N,N'-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine) as a metalloligand and [Ln(III)(hfac)3(H2O)2] (Hhfac = hexafluoroacetylacetone) as a lanthanide precursor compound. Also reported with this series is the Zn-Dy analog [Zn(II)2(L)2(PhCOO)2Dy(III)2(hfac)4] 6 to help us in understanding the magnetic properties of these compounds. The compounds 1-6 are isostructural. Both hexafluoroacetylacetonate and benzoate play crucial roles in these structures as coligands in generating a tetranuclear core of high thermodynamic stability through a self-assembly process. The metal centers are arranged alternately at the four corners of this rhombic core, and the carboxylato oxygen atoms of each benzoate moiety bind all of the four metal centers of this core in a rare μ4-η(2):η(2) bridging mode as confirmed by X-ray crystallography. The magnetic susceptibility and magnetization data confirm a paramagnetic behavior, and no remnant magnetization exists in any of these compounds at vanishing magnetic field. The metal centers are coupled in an antiferromagnetic manner in these compounds. The [Co(II)2Dy(III)2] compound exhibits a slow magnetic relaxation below 6 K, as proven by the AC susceptibility measurements; the activation energy reads U/kB = 8.8 K (τ0 = 2.0 × 10(-7) s) at BDC = 0, and U/kB = 7.8 K (τ0 = 3.9 × 10(-7) s) at BDC = 0.1 T. The [Zn(II)2Dy(III)2] compound also behaves as a single-molecule magnet with U/kB = 47.9 K and τ0 = 2.75 × 10(-7) s.

  2. Mo{sub 2}NiB{sub 2}-type (Gd, Tb, Dy){sub 2}Ni{sub 2.35}Si{sub 0.65} and La{sub 2}Ni{sub 3}-type (Dy, Ho){sub 2}Ni{sub 2.5}Si{sub 0.5} compounds: Crystal structure and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, Moscow 119992, GSP-2 (Russian Federation); Isnard, O. [CNRS, Insitut. Néel, 25 rue des Martyrs BP166, F-38042 Grenoble (France); Université Grenoble Alpes, Inst. Néel, F-38042 Grenoble (France); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600 036 (India); Malik, S.K. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59082-970 (Brazil)

    2015-05-15

    The crystal structure of new Mo{sub 2}NiB{sub 2}-type (Gd, Tb, Dy){sub 2}Ni{sub 2.35}Si{sub 0.65} (Immm, No. 71, oI10) and La{sub 2}Ni{sub 3}-type (Dy, Ho){sub 2}Ni{sub 2.5}Si{sub 0.5} (Cmce No. 64, oC20) compounds has been established using powder X-ray diffraction studies. Magnetization measurements show that the Mo{sub 2}NiB{sub 2}-type Gd{sub 2}Ni{sub 2.35}Si{sub 0.65} undergoes a ferromagnetic transition at ~66 K, whereas isostructural Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} shows an antiferromagnetic transition at ~52 K and a field-induced metamagnetic transition at low temperatures. Neutron diffraction study shows that, in zero applied field, Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} exhibits c-axis antiferromagnetic order with propagation vector K=[1/2, 0, 1/2] below its magnetic ordering temperature and Tb magnetic moment reaches a value of 8.32(5) μ{sub B} at 2 K. The La{sub 2}Ni{sub 3}-type Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} exhibits ferromagnetic like transition at ~42 K with coexisting antiferromagnetic interactions and field induced metamagnetic transition below ~17 K. The magnetocaloric effect of Gd{sub 2}Ni{sub 2.35}Si{sub 0.65}, Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} and Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} is calculated in terms of isothermal magnetic entropy change and it reaches a maximum value of −14.3 J/kg K, −5.3 J/kg K and −10.3 J/kg K for a field change of 50 kOe near 66 K, 52 K and 42 K, respectively. Low temperature magnetic ordering with enhanced anisotropic effects in Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} and Dy{sub 2}Ni{sub 2.35}Si{sub 0.65} is accompanied by a positive magnetocaloric effect with isothermal magnetic entropy changes of +12.8 J/kg K and ~+9.9 J/kg K, respectively at 7 K for a field change of 50 kOe. - Graphical abstract: The (Gd, Tb, Dy){sub 2}Ni{sub 2.35}Si{sub 0.65} supplement the series of Mo{sub 2}NiB{sub 2}-type rare earth compounds, whereas the (Dy, Ho){sub 2}Ni{sub 2.5}Si{sub 0.5} supplement the series of La{sub 2}Ni{sub 3}-type rare

  3. Hetero-metallic {3d-4f-5d} complexes: preparation and magnetic behavior of trinuclear [(L(Me2)Ni-Ln){W(CN)(8)}] compounds (Ln = Gd, Tb, Dy, Ho, Er, Y; L(Me2) = Schiff base) and variable SMM characteristics for the Tb derivative.

    Science.gov (United States)

    Sutter, Jean-Pascal; Dhers, Sébastien; Rajamani, Raghunathan; Ramasesha, S; Costes, Jean-Pierre; Duhayon, Carine; Vendier, Laure

    2009-07-06

    Assembling bimetallic {Ni-Ln}(3+) units and {W(CN)(8)}(3-) is shown to be an efficient route toward heteronuclear {3d-4f-5d} compounds. The reaction of either the binuclear [{L(Me2)Ni(H(2)O)(2)}{Ln(NO(3))(3)}] complexes or their mononuclear components [L(Me2)Ni] and Ln(NO(3))(3) with (HNBu(3))(3){W(CN)(8)} in dmf followed by diffusion of tetrahydrofuran yielded the trinuclear [{L(Me2)NiLn}{W(CN)(8)}] compounds 1 (Ln = Y), 2a,b (Gd), 3a,b (Tb), 4 (Dy), 5 (Ho), and 6 (Er) as crystalline materials. All of the derivatives possess the trinuclear core resulting from the linkage of the {W(CN)(8)} to the Ni center of the {Ni-Ln} unit. Differences are found in the solvent molecules acting as ligands and/or in the lattice depending on the crystallization conditions. For all the compounds ferromagnetic {Ni-W} and {Ni-Ln} (Ln = Gd, Tb, Dy, and Er} interactions are operative resulting in high spin ground states. Parameterization of the magnetic behaviors for the Y and Gd derivatives confirmed the strong cyano-mediated {Ni-W} interaction (J(NiW) = 27.1 and 28.5 cm(-1)) compared to the {Ni-Gd} interaction (J(NiGd) = 2.17 cm(-1)). The characteristic features for slow relaxation of the magnetization are observed for two Tb derivatives, but these are modulated by the crystal phase. Analysis of the frequency dependence of the alternating current susceptibility data yielded U(eff)/k(B) = 15.3 K and tau(0) = 4.5 x 10(-7) s for one derivative whereas no maxima of chi(M)'' appear above 2 K for the second one.

  4. Thermodynamic studies on LnCoO{sub 3}(s) (Ln = Dy, Ho) by solid-state electrochemical cells

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Abhay [Product Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Dash, Smruti [Product Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)], E-mail: smruti@barc.gov.in; Parida, S.C.; Venugopal, V. [Product Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2009-01-05

    Ternary oxides, DyCoO{sub 3}(s) and HoCoO{sub 3}(s) have been synthesized by citrate-nitrate gel combustion method and characterized by X-ray powder diffraction method. The standard molar Gibbs energies of formation of DyCoO{sub 3}(s) and HoCoO{sub 3}(s) have been measured using solid oxide galvanic cell technique employing yttria-stabilized zirconia (YSZ) and calcia-stabilized zirconia (CSZ) as solid electrolyte tubes, respectively. The standard molar Gibbs energies of formation of DyCoO{sub 3}(s) and HoCoO{sub 3}(s) were calculated from the measured e.m.f. data and are given as: {delta}{sub f}G{sub m}{sup o}(DyCoO{sub 3},s,T)kJmol{sup -1}({+-}4)=-1211.3+0.2449{sup *}(TK),(1013K{<=}T{>=}1167K), {delta}{sub f}G{sub m}{sup o}(HCoO{sub 3},s,T)kJmol{sup -1}({+-}4)=-1237.8+0.2590{sup *}(TK).(964K{<=}T{>=}1102K), A set of self consistent thermodynamic functions for LnCoO{sub 3}(s) (Ln = La, Nd, Sm, Eu, Gd, Dy, Ho) has been computed from available experimental data in the literature.

  5. On the structures of the rare-earth metal germanides from the series REAl1-xGe3 (RE = Nd, Sm, Gd, Tb, Dy, Ho; 0.6 < x < 0.9). A tale of vacancies at the Al sites and the concomitant structural modulations.

    Science.gov (United States)

    Zhang, Jiliang; Liu, Yanyan; Shek, Chan Hung; Wang, Yingmin; Bobev, Svilen

    2017-07-18

    A series of ternary rare-earth metal aluminum germanides with the general formula REAl1-xGe3 (RE = Nd, Sm, Gd, Tb, Dy, and Ho; 0.6 < x < 0.9) have been synthesized by direct fusion of the corresponding elements. Their structures have been characterized by single-crystal X-ray diffraction and selected area electron diffraction methods. The average structure for all members is a representative of the orthorhombic SmNiGe3-type structure (Pearson symbol oS20, space group Cmmm), where the Al atoms occupy the Ni site, and the deep off-stoichiometry is due to statistical vacancies at this position. Considering long-range ordering of the vacancies, a monoclinic and a different orthorhombic structure, which represent idealized ordered variants, are possible, and the structural evolution depending on the nature of the rare-earth metals and the amount of vacancies at the aluminum site are discussed. Commensurate and incommensurate structural modulations based on these parent structures are also observed by electron diffraction, attesting to the great structural complexity in these systems. Magnetic susceptibility measurements are presented and discussed, along with the results from electronic band-structure calculations.

  6. Physical Properties of RE2 Ti3 Si4 (RE=Gd,Tb,Dy,Ho and Er)from First-principles Calculations%RE2 Ti3Si4(RE=Gd,Tb,Dy,Ho和Er)物理性质的第一性原理研究

    Institute of Scientific and Technical Information of China (English)

    陶小马; 陈晨; 郭子凤; 王戎丞; 陈红梅; 欧阳义芳

    2014-01-01

    【目的】对 RE2 Ti3 Si4(RE=Gd,Tb,Dy,Ho和 Er)的物理性能进行研究。【方法】利用基于密度泛函的第一性原理方法对 RE2 Ti3 Si4(RE=Gd,Tb,Dy,Ho 和 Er)的结构性质、电子结构、力学以及热力学性质进行计算。对RE2 Ti3 Si4单晶的弹性常数,多晶的体积模量、剪切模量和杨氏模量都进行了计算。利用准谐的德拜模型计算获得了体积模量、比热熔和热膨胀系数随着温度和压强的变化,并进行了相关的讨论。【结果】RE2 Ti3 Si4的晶格常数计算值和实验值吻合较好。【结论】形成焓的计算值随着稀土元素原子序数的增加而呈现微小的下降趋势,这表明化合物的稳定性随着原子序数的增加而加强。电子态密度显示在费米能级之下,Ti-3d和 RE-5d的态密度有着很强的杂化现象。%Objective]Physical properties of the RE2 Ti3 Si4 (RE=Gd,Tb,Dy,Ho and Er)are studied.[Methods]We present the structural,electronic structure,mechanical and thermody-namic properties of the RE2 Ti3 Si4 (RE=Gd,Tb,Dy,Ho and Er)by using first-principles calcu-lations based on the density functional theory (DFT).[Results]The calculated lattice constants of RE2 Ti3 Si4 are all in good agreement with experimental data.The single crystal elastic con-stants of RE2 Ti3 Si4 have been calculated,and the bulk,shear and Young's modulus are all been estimated in this work.Finally,using a quasi-harmonic Debye model,the bulk modulus,heat ca-pacity,and coefficient of thermal expansion have also been obtained and discussed.[Conclusion]The calculated formation enthalpies of the RE2 Ti3 Si4 show tiny decline trend with the increas-ing atomic number,which indicates that phase stability of RE2 Ti3 Si4 enhance slightly with in-creasing atomic number.The electronic densities of states indicate that Ti-3d and RE-5d peaks show strong hybridization below the Fermi level.

  7. Spin structure and magnetic frustration in multiferroic RMn2O5 (R=Tb,Ho,Dy)

    NARCIS (Netherlands)

    Blake, G.R.; Chapon, L.C.; Radaelli, P.G.; Park, S.; Hur, N.; Cheong, S-W.; Rodríguez-Carvajal, J.

    2005-01-01

    We have studied the crystal and magnetic structures of the magnetoelectric materials RMn2O5 (R=Tb,Ho,Dy) using neutron diffraction as a function of temperature. All three materials display incommensurate antiferromagnetic ordering below 40 K, becoming commensurate on further cooling. For R=Tb,Ho, a

  8. Thermodynamic modeling of the RE–Pb (RE = Sc, Dy, Gd) systems

    Energy Technology Data Exchange (ETDEWEB)

    Iddaoudi, A., E-mail: iddaoudi19@gmail.com [Laboratoire de Thermodynamique et Energétique, LTE, Université Ibn-Zohr, B.P. 8106 Agadir (Morocco); Servant, C., E-mail: colette.servant@orange.fr [Laboratoire de Physicochimie de l’Etat Solide, ICMMO, Université Paris-Sud, 91405 Orsay Cedex (France); Selhaoui, N.; Kardellass, S.; Mahdouk, K.; Bouirden, L. [Laboratoire de Thermodynamique et Energétique, LTE, Université Ibn-Zohr, B.P. 8106 Agadir (Morocco)

    2014-03-15

    Highlights: • Rare earth (RE) and Pb alloys or compounds are interesting as magnetic materials. • The phase diagrams and thermodynamic properties of RE–Pb (RE = Sc, Dy, Gd) systems have been assessed. • The CALPHAD method was used with the Redlich–Kister model to optimize the solution phases. • A self-consistent set of thermodynamic parameters has been evaluated. • A good agreement was found between the calculation and experiments. -- Abstract: The phase diagrams and thermodynamic properties of RE–Pb (RE = Sc, Dy, Gd) systems have been assessed by means of the CALPHAD method. The solution phases (liquid, fcc, bcc and hcp) were described by the sublattice formalism and the excess term of the Gibbs energy with the Redlich–Kister equation. The stoichiometric intermetallic compounds (Sc{sub 5}Pb{sub 3}, Sc{sub 6}Pb{sub 5}, Dy{sub 5}Pb{sub 4}, DyPb, DyPb{sub 2}, DyPb{sub 3}, β-Gd{sub 5}Pb{sub 4}, α-Gd{sub 5}Pb{sub 4}, Gd{sub 11}Pb{sub 10}, Gd{sub 6}Pb{sub 7}, GdPb{sub 2} and GdPb{sub 2}) were modeled as line compounds. The non-stoichiometric Dy{sub 5}Pb{sub 3} and Gd{sub 5}Pb{sub 3} phases with a narrow homogeneity range were modeled using a two-sublattice model with substitution. A consistent set of the thermodynamic parameters leading to a reasonable agreement between the calculated results and literature data was obtained.

  9. Evidence for triaxial deformation near N=86 : Collective bands in Dy-152,Dy-153 and Ho-153

    NARCIS (Netherlands)

    Appelbe, DE; Twin, PJ; Beausang, CW; Cullen, DM; Curien, D; Duchene, G; Erturk, S; Finck, C; Haas, B; Paul, ES; Radford, DC; Rigollet, C; Smith, MB; Stezowski, O; Waddington, JC; Wilson, AN

    2002-01-01

    The N=86,87 isotopes of dysprosium and holmium have been investigated using the Eurogam II gamma-ray spectrometer. A new collective rotational band has been observed in Ho-153 and the previously observed nui(13/2) band in Dy-153 has been extended to much higher spin. Comparing these bands and

  10. Lattice dynamics of rare-earth titanates with the structure of pyrochlore R 2Ti2O7 ( R = Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu): Ab initio calculation

    Science.gov (United States)

    Chernyshev, V. A.; Petrov, V. P.; Nikiforov, A. E.

    2015-05-01

    The ab initio calculation has been performed for the crystal structure and the phonon spectrum of titanates with the structure of pyrochlore R 2Ti2O7 ( R = Gd-Lu). The frequencies and types of fundamental vibrations have been found. For R = Tb, Tm, and Yb, this calculation has been carried out for the first time; furthermore, there is no available information on experimental studies of the phonon spectrum for Tm and Yb. The influence of hydrostatic pressure to 35 GPa on the structure, dynamics, and elastic properties of the Gd2Ti2O7 lattice has been investigated. The dependence of the phonon frequencies on the pressure has been obtained. The calculations have predicted that the relative change in the pyrochlore structure volume during compression at pressures to 35 GPa is well described by the third-order Birch-Murnaghan equation of states. The results of the calculations agree with the available experimental data. It has been shown that the structural, dynamic, and elastic properties of the R 2Ti2O7 crystal lattice can be adequately described in the case where the inner shells of the RE ion up to 4 f are replaced by the pseudopotential.

  11. Chemically modulated multiferroicity in Dy-doped Gd2Ti2O7

    Science.gov (United States)

    Lin, L.; Zhao, Z. Y.; Liu, D.; Xie, Y. L.; Dong, S.; Yan, Z. B.; Liu, J.-M.

    2013-05-01

    The ferroelectricity and magnetoelectric coupling of Gd2Ti2O7 and Gd2-xDyxTi2O7 with Dy3+ substitution of Gd3+ are investigated. For Gd2Ti2O7, a ferroelectric polarization emerges at ˜30 K and is only ˜1.80 μC/m2 at 2 K, while the magnetoelectric response is quite weak. The Dy3+ substitution in Gd2-xDyxTi2O7, however, results in significant enhancement of polarization with remarkable magnetoelectric response up to 35% at 2 K under a magnetic field of 9 T, suggesting the multiferroicity of Gd2-xDyxTi2O7. It is understood that the chemical modulation of the multiferroicity is basically related to the extreme sensitivity of the spin-spin interactions in this highly frustrated system.

  12. Therapeutical radiopharmaceuticals based In vivo generator system [{sup 166} Dy] Dy/{sup 166} Ho; Radiofarmacos terapeuticos basados en un sistema de generador In vivo [{sup 166}Dy] Dy/{sup 166}Ho

    Energy Technology Data Exchange (ETDEWEB)

    Ferro F, G.; Garcia S, L.; Monroy G, F.; Tendilla, J.I. [Gerencia de Aplicaciones Nucleares en la Salud, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Pedraza L, M.; Murphy, C.A. de [Departamento de Medicina Nuclear, Instituto Nacional de Pediatria, Mexico D.F. (Mexico)

    2002-07-01

    At the idea to administer to a patient a molecule containing in it structure a father radionuclide, with a half life enough large which allows to the radiolabelled molecule to take up position specifically in a white tissue and decaying In vivo to the daughter radionuclide with properties potentially therapeutic, it is known as In vivo generator system. In this work the preparation and the preliminary dosimetric valuations of radiopharmaceuticals based In vivo generator system {sup 166} Dy Dy/{sup 166} Ho for applications in radioimmunotherapy, in the treatment of the rheumatoid arthritis and in the bone marrow ablation (m.o.) for candidates patients to bone marrow transplant are presented. (Author)

  13. Ternary germanides RERhGe2 (RE = Y, Gd-Ho) - New representatives of the YIrGe2 type

    Science.gov (United States)

    Voßwinkel, Daniel; Heletta, Lukas; Hoffmann, Rolf-Dieter; Pöttgen, Rainer

    2016-11-01

    The YIrGe2 type ternary germanides RERhGe2 (RE = Y, Gd-Ho) were synthesized from the elements by arc-melting and characterized by powder X-ray diffraction. The structure of DyRhGe2 was refined from single crystal X-ray diffractometer data: Immm, a = 426.49(9), b = 885.0(2), c = 1577.4(3) pm, wR2 = 0.0533, 637 F2 values, 30 variables (300 K data). The structure contains two crystallographically independent dysprosium atoms in pentagonal prismatic and hexagonal prismatic coordination. The three-dimensional [RhGe2] polyanion is stabilized through covalent Rh-Ge (243-261 pm) and Ge-Ge (245-251 pm) bonding. The close structural relationship with the slightly rhodium-poorer germanides RE5Rh4Ge10 (≡ RERh0.8Ge2) is discussed. Temperature-dependent magnetic susceptibility measurements reveal Pauli paramagnetism for YRhGe2 and Curie-Weiss paramagnetism for RERhGe2 with RE = Gd, Tb, Dy and Ho. These germanides order antiferromagnetically at TN = 7.2(5), 10.6(5), 8.1(5), and 6.4(5) K, respectively.

  14. High-pressure synthesis of a La orthosilicate and Nd, Gd, and Dy disilicates

    Science.gov (United States)

    Liu, Xiaoyang; Fleet, Michael E.

    2002-11-01

    Several rare-earth silicates have been synthesized at 10 GPa and 1600-1700 °C: a La orthosilicate (La4Si3O12) with a defect Ba3(PO4)2-type, a new structure type (K) for Nd and Gd disilicates (Nd2Si2O7 and Gd2Si2O7) with a diorthosilicate structure, and a new structure type (L) for Dy disilicate (Dy2Si2O7) with a structure containing linear triple tetrahedral groups [Si3O10], but having one in six atoms distributed with 50% occupancy over two tetrahedral positions.

  15. Efficient High Power Ho,Tm:GdVO4 Laser

    Institute of Scientific and Technical Information of China (English)

    WANG Yue-Zhu; ZHU Guo-Li; JU You-Lun; YAO Bao-Quan

    2011-01-01

    We report a 22.3 W cw diode-pumped cryogenic Ho(0.5at. %), Tm(at.5%):GdVC>4 laser at a wavelength of 2.05 fzm. It is pumped by two fiber-coupled laser diodes with a fiber core diameter of 0.4 mm, both of which provide 42 W pump power near 802 nm. A cw output power of 22.3 W was obtained at the pump power of 51.0 W, corresponding to an optical-to-optical conversion efficiency of 43.7% when the ratio of the pump beam to oscillating laser beam in the crystal was ^1.33:1. The M2 factor was found to be 2.0 under an output power of 16.5 W.%@@ We report a 22.3 W ew diode-pumped cryogenic Ho(0.5at.%),Tm(at.5%):GdVO4 laser at a wavelength of 2.05μm.It is pumped by two fiber-coupled laser diodes with a fiber core diameter of 0.4 mm,both of which provide 42W pump power near 802 nm.A cw output power of 22.3 W was obtained at the pump power of 51.0W,corresponding to an optical-to-optical conversion efficiency of 43.7%when the ratio of the pump beam to oscillating laser beam in the crystal was ~1.33:1.The M2 factor was found to be 2.0 under an output power of 16.5 W.

  16. CeNi3-type rare earth compounds: crystal structure of R3Co7Al2 (R=Y, Gd-Tm) and magnetic properties of {Gd-Er}3Co7Al2, {Tb, Dy}3Ni8Si and Dy3Co7.68Si1.32

    Science.gov (United States)

    Morozkin, A. V.; Yapaskurt, V. O.; Nirmala, R.; Quezado, S.; Malik, S. K.

    2017-03-01

    The crystal structure of new CeNi3-type {Y, Gd-Tm}3Co7Al2 (P63/mmc. N 194, hP24) compounds has been established using powder X-ray diffraction studies. The magnetism of Tb3Ni8Si and Dy3Ni8Si is dominated by rare earth sublattice and the magnetic properties of R3Co7Al2 (R =Gd-Er) and Dy3Co7.68Si1.32 are determined by both rare earth and cobalt sublattices. Magnetization data indicate ferromagnetic ordering of {Tb, Dy}3Ni8Si at 32 K and 21 K, respectively. Gd3Co7Al2 and Tb3Co7Al2 exhibit ferromagnetic ordering at 309 K and 209 K, respectively, whereas Dy3Co7Al2, Ho3Co7Al2, Er3Co7Al2 and Dy3Co7.68Si1.32 show a field dependent ferromagnetic-like ordering at 166 K, 124 K, 84 K and 226 K, respectively followed by a low temperature transition at 34 K for Dy3Co7Al2, 18 K for Ho3Co7Al2, 56 K for Er3Co7Al2, 155 K and 42 K for Dy3Co7.68Si1.32. Among these compounds, Dy3Ni8Si shows largest magnetocaloric effect (isothermal magnetic entropy change) of -11.6 J/kg·K at 18 K in field change of 50 kOe, whereas Tb3Co7Al2, Dy3Co7Al2 and Dy3Co7.68Si1.32 exhibit best permanent magnet properties in the temperature range of 2-5 K with remanent magnetization of 11.95 μB/fu, 12.86 μB/fu and 14.4 μB/fu, respectively and coercive field of 3.0 kOe, 1.9 kOe and 4.4 kOe, respectively.

  17. Comparison of the Solid Solution Properties of Mg-RE (Gd, Dy, Y Alloys with Atomistic Simulation

    Directory of Open Access Journals (Sweden)

    Yurong Wu

    2008-01-01

    Full Text Available Molecular dynamic simulations have been performed to study the solid solution mechanism of Mg100-xREx (RE=Gd,Dy,Y, x=0.5,1,2,3,4  at.%. The obtained results reveal that the additions of Gd, Dy and Y increase the lattice constants of Mg-RE alloys. Also the axis ratio c/a remains unchanged with increase in temperature, restraining the occurrence of nonbasal slip and twinning. Furthermore, it is confirmed that bulk modulus of Mg alloys can be increased remarkably by adding the Gd, Dy, Y, especially Gd, because the solid solubility of Gd in Mg decrease sharply with temperature in comparison with Dy and Y. Consequently, the addition of the RE can enhance the strength of Mg-based alloys, which is in agreement with the experimental results.

  18. Q-switched Ho:YLF laser pumped by a Tm:GdVO4 laser.

    CSIR Research Space (South Africa)

    Esser, MJD

    2009-06-01

    Full Text Available The authors have, through careful analysis of spectroscopic data, designed and demonstrated a diode-end-pumped, quasicontinuous wave Tm:GdVO4 laser operating at 1892 nm in order to pump a Q-switched Ho:YLF laser. The Ho:YLF maximum output energy...

  19. The normal and inverse magnetocaloric effect in RCu2 (R=Tb, Dy, Ho, Er) compounds

    Science.gov (United States)

    Zheng, X. Q.; Xu, Z. Y.; Zhang, B.; Hu, F. X.; Shen, B. G.

    2017-01-01

    Orthorhombic polycrystalline RCu2 (R=Tb, Dy, Ho and Er) compounds were synthesized and the magnetic properties and magnetocaloric effect (MCE) were investigated in detail. All of the RCu2 compounds are antiferromagnetic (AFM) ordered. As temperature increases, RCu2 compounds undergo an AFM to AFM transition at Tt and an AFM to paramagnetic (PM) transition at TN. Besides of the normal MCE around TN, large inverse MCE around Tt was found in TbCu2 compound. Under a field change of 0-7 T, the maximal value of inverse MCE is even larger than the value of normal MCE around TN for TbCu2 compound. Considering of the normal and inverse MCE, TbCu2 shows the largest refrigerant capacity among the RCu2 (R=Tb, Dy, Ho and Er) compounds indicating its potential applications in low temperature multistage refrigeration.

  20. High-pressure synthesis of a La orthosilicate and Nd, Gd, and Dy disilicates

    CERN Document Server

    Liu Xiao Yang

    2002-01-01

    Several rare-earth silicates have been synthesized at 10 GPa and 1600-1700 deg. C: a La orthosilicate (La sub 4 Si sub 3 O sub 1 sub 2) with a defect Ba sub 3 (PO sub 4) sub 2 -type, a new structure type (K) for Nd and Gd disilicates (Nd sub 2 Si sub 2 O sub 7 and Gd sub 2 Si sub 2 O sub 7) with a diorthosilicate structure, and a new structure type (L) for Dy disilicate (Dy sub 2 Si sub 2 O sub 7) with a structure containing linear triple tetrahedral groups [Si sub 3 O sub 1 sub 0], but having one in six atoms distributed with 50% occupancy over two tetrahedral positions.

  1. High-pressure synthesis of a La orthosilicate and Nd, Gd, and Dy disilicates

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiaoyang; Fleet, Michael E [Department of Earth Sciences, University of Western Ontario, London, ON (Canada)

    2002-11-11

    Several rare-earth silicates have been synthesized at 10 GPa and 1600-1700 deg. C: a La orthosilicate (La{sub 4}Si{sub 3}O{sub 12}) with a defect Ba{sub 3}(PO{sub 4}){sub 2}-type, a new structure type (K) for Nd and Gd disilicates (Nd{sub 2}Si{sub 2}O{sub 7} and Gd{sub 2}Si{sub 2}O{sub 7}) with a diorthosilicate structure, and a new structure type (L) for Dy disilicate (Dy{sub 2}Si{sub 2}O{sub 7}) with a structure containing linear triple tetrahedral groups [Si{sub 3}O{sub 10}], but having one in six atoms distributed with 50% occupancy over two tetrahedral positions.

  2. Synthesis and photoluminescent characteristics of Dy3+ doped Gd2O3 phosphors

    Science.gov (United States)

    Jeena, T. R.; Ezhil Raj, A. Moses; Bououdina, M.

    2017-02-01

    Pure and dysprosium doped gadolinium oxide nanoparticles for three different concentrations (2, 5 and 10 mol.%) were synthesized by auto-combustion method using citric acid as fuel. The nanoparticles obtained were characterized using powder x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), UV–vis–NIR spectroscopy and photoluminescence (PL) spectroscopy techniques. XRD pattern revealed the crystalline cubic phase with space group Ia3 (Space Group: 206) for both the pure and doped Gd2O3 nanoparticles. The metal oxide phase formation and purity of Gd2O3 nanoparticles were further confirmed from the FTIR spectra. Morphology of the pure Gd2O3 powder is loosely dispersed clusters of tiny particles with microscopic pores, whereas for the doped samples aggregates were broken to form small clusters. Optical absorption measurements were recorded in the UV–vis–NIR wavelength region and the optical band gap variations with dopant concentration were discussed. The PL spectra of pure and Dy3+ doped Gd2O3 nanoparticles have been studied and the effect of emitted light on the yellow-to-blue intensity ratio (Y/B) of Dy3+ emission was demonstrated.

  3. Growth and spectra properties of Tm, Ho doped and Tm, Ho co-doped CaGdAlO{sub 4} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Di, Juqing [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Xu, Xiaodong, E-mail: xdxu79@mail.sic.ac.cn [Key Laboratory of Transparent and Opto-functional Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); Xia, Changtai, E-mail: xia_ct@siom.ac.cn [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Sai, Qinglin [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhou, Dahua [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Lv, Zhengyong [Department of Electronics and Information Materials, School of Materials Sciences and Engineering, Shanghai University, Shanghai 200072 (China); Xu, Jun [Key Laboratory of Transparent and Opto-functional Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2014-11-15

    Growth of Tm, Ho doped and Tm, Ho co-doped CaGdAlO{sub 4} crystals by Czochralski method are investigated for the first time. Tm:CaGdAlO{sub 4} crystal without any crack was obtained. The segregation coefficient and XRD were detected and the results revealed that the cell parameters decreased with increasing of the doping concentration. The absorption spectra, J–O parameters, emission spectra and fluorescence lifetime of were discussed. The absorption cross sections were calculated to be 0.61×10{sup −20} cm{sup 2} and 1.49×10{sup −20} cm{sup 2} at 793 nm and 798 nm for a polarization and c polarization of Tm:CaGdAlO{sub 4} crystal, and the stimulated emission cross-section was calculated to be 0.36×10{sup −20} cm{sup 2} at 1762 nm. The stimulated emission cross-section of Ho:CaGdAlO{sub 4} crystal was calculated to be 1.18×10{sup −20} cm{sup 2} at 2002 nm. The width of Tm,Ho:CaGdAlO{sub 4} emission band is almost 600 nm. The results show that Tm:CaGdAlO{sub 4}, Ho:CaGdAlO{sub 4} and Tm,Ho:CaGdAlO{sub 4} crystals were excellent potential ultrafast laser media. - Highlights: • Tm:CGA, Tm,Ho:CGA and Ho:CGA crystals were grown for the first time. • The absorption and emission properties were investigated for the first time. • J–O theory was used to evaluate the potential of laser performance of Tm:CGA, Tm,Ho:CGA and Ho:CGA crystals. • The energy transfer coefficients between Tm and Ho ions in this crystal were studied.

  4. Effect of Ho-doping on microstructure and magnetostriction of TbDyFe alloys

    Institute of Scientific and Technical Information of China (English)

    JIANG Minhong; GU Zhengfei; CHENG Gang; LIU Xinyu

    2009-01-01

    Tb0.3Dy0.7HoxFe1.95 (x=0.00, 0.05, 0.10, 0.15, 0.20, 0.35, 0.50, 0.65) quaternary alloys were prepared by arc-melting and followed by annealing. The phases present and structure of the alloys were determined using a D8-Advance X-ray diffractometer. The magnetostriction of the alloys was studied by standard strain gauge technique. The dependence of Ho content on the structure, magnetostriction and density of the alloys was investigated in detail. The research results showed that Ho-doping did not change MgCu2-type cubic Laves structure in Tb0.3Dy0.7Fe1.95. When Ho content x≤0.2, rich rare earth phase presented in the alloys increased and magnetostriction of the alloys reduced evidently with increasing x, but for alloys with x>0.2, the content of rich rare earth phase started to reduce and the magnetostriction increased quickly, especially at low magnetic field in the alloy with x=0.65 due to separation of rich rare earth phases on the surface of the alloy.

  5. BaGdF5:Dy(3+),Tb(3+),Eu(3+) multifunctional nanospheres: paramagnetic, luminescence, energy transfer, and tunable color.

    Science.gov (United States)

    Guan, Hongxia; Song, Yanhua; Zheng, Keyan; Sheng, Ye; Zou, Haifeng

    2016-05-18

    A series of Dy(3+),Tb(3+) and Eu(3+) singly, doubly or triply doped BaGdF5 phosphors were synthesized by a one-step hydrothermal method with l-arginine, and their energy transfer, migrations and multicolored luminescence properties were investigated in detail. The as-prepared Dy(3+),Tb(3+) or Eu(3+) doped samples showed strong blue, green and red emission, respectively. Different hues of green and red light were obtained by co-doped Dy(3+),Tb(3+) and Tb(3+),Eu(3+) in the BaGdF5 host, respectively. More significantly, in the Dy(3+),Tb(3+),Eu(3+) tri-doped BaGdF5 phosphors, colors changed from yellow green to orange red by adjusting the doping concentration of Eu(3+). Energy migrations from Dy(3+) to Tb(3+) and from Tb(3+) to Eu(3+) are reported in detail. Furthermore, the obtained samples exhibit paramagnetic properties at room temperature and low temperature. It is obvious that these Dy(3+), Tb(3+), Eu(3+) singly or doubly or triply doped BaGdF5 nanomaterials with tunable multicolored luminescence properties may have potential applications in the fields of full-color displays, biological labels and bio-separation.

  6. Investigation of complexes with bone affinity using the In vivo generator system {sup 166} Dy/{sup 166} Ho; Investigacion de complejos con afinidad osea utilizando el Sistema de Generador in vivo {sup 166} Dy/{sup 166} Ho

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza L, M

    2006-07-01

    The importance of this original research lies in the fact that it has proven that the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system is a stable complex that can be used as a therapeutic radiopharmaceutical. Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. Bone-seeking radiopharmaceuticals such as {sup 166}Ho-DOTMP or {sup 153}Sm-DTMP, have been proposed for delivering ablative radiation doses to marrow in multiple myeloma and other hematological malignancies or have shown excellent results in palliative bone metastasis pain therapy, respectively. As lanthanides have similar chemical characteristics the phosphonate with bone affinity (EDTMP) labeled with Dy/Ho can be used for marrow ablation while causing minimal irradiation to normal organs. This in vivo generator system has not been previously reported. The aim of this research was to label EDTMP (ethylene diamine tetramethylene phosphonate) with {sup 166}Dy/{sup 166}Ho; to evaluate the in vitro and in vivo stability of both {sup 166}Dy-EDTMP and {sup 166}Ho-EDTMP complexes when the daughter {sup 166}Ho is formed as a dysprosium decay product; to determine the bone marrow cytotoxic and genotoxic effect in mice and to evaluate, by histopathology, the myeloablative potential of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system. {sup 166}Dy was obtained by neutron irradiation of enriched {sup 164}Dy{sub 2}O{sub 3} in a TRIGA Mark III reactor. Labeling was carried out in an aqueous phosphate medium at pH 8.0 by addition of {sup 166}DyCl{sub 3} to EDTMP at a molar ratio 1:1.75, with >99 % radiochemical purity, as determined by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). In vitro studies demonstrated that {sup 166}Dy/{sup 166}Ho-EDTMP is unstable after dilution in saline but stable in human serum with no translocation of the daughter nucleus

  7. Preparation of {sup 166} Dy/{sup 166} Ho DTPA-bis biotin as a system of In vivo generator; Preparacion de {sup 166} Dy/{sup 166} Ho DTPA-bis biotina como un sistema de generador In vivo

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez V, M.R

    2003-07-01

    The objective of this work was to synthesize the complex {sup 166} Dy/{sup 166} Ho - diethylen triamine pentaacetic-bis Biotin ({sup 166} Dy/{sup 166} Ho DTPA-bis Biotin) to evaluate its potential as a new radiopharmaceutical in directed radiotherapy. The Dysprosium-166 was obtained for neutron irradiation of {sup 164} Dy{sub 2}0{sub 3} in the TRIGA Mark III reactor. The labelled was carried out in aqueous solution to p H 8.0 for addition of {sup 166} Dy Cl{sub 3} to the diethylen triamine pentaacetic-{alpha}, {omega}-bis Biotin (DTPA-bis Biotin). The radiochemical purity was determined for HPLC and ITLC. The biological integrity of the marked biotin is evaluated by the biological recognition of the avidin for HPLC - molecular exclusion with and without avidin addition. The studies of stability in vitro were made in dilutions of saline solution to 0.9% and with human serum at 37 C incubated 1 and 24 hours. The complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin was obtained with a radiochemical purity of 99.1 {+-} 0.6%. The biological recognition of the complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin for the avidin it doesn't affect the labelling procedure. The studies in vitro demonstrated that the {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin is stable after the dilution in saline solution and in human serum that there is not translocation of the one radionuclide subsequent son to the beta decay of the {sup 166} Dy that could produce the {sup 166} Ho{sup 3+} liberation. The studies of Biodistribution in healthy mice demonstrated that the one complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin have a high renal distribution. In conclusion the radiolabelled biotin in this investigation has the appropriate properties to be used as an In vivo generator system stable for directed radiotherapy. (Author)

  8. Neutron diffraction studies of R{sub 2}RhSi{sub 3} (R=Dy, Ho, Er) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Bazela, W.; Penc, B.; Stuesser, N.; Szytula, A.; Wawrzynska, E.; Zygmunt, A

    2004-07-15

    Powder neutron diffraction and magnetic measurements have been carried out on R{sub 2}RhSi{sub 3} (R=Dy, Ho and Er) compounds at low temperatures. These compounds crystallize in a derivative of the hexagonal AlB{sub 2}-type structure and are antiferromagnets with the Neel temperatures equal to: 6.3 K for R=Dy, 5.2 K for R=Ho and 5 K for R=Er. Below these temperatures the magnetic order is described by the propagation vector: k=(0,0,((1)/(2))) for R=Dy, k=(((1)/(2)),0,0) for R=Ho and k=(0,0,0) for R=Er. This magnetic order is stable in the temperature range between 1.5 K and the Neel temperature.

  9. Magnetic ordering of R{sub 3}Cu{sub 4}Sn{sub 4} (R = Tb, Dy, Ho and Er)

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzynska, E [M Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland); Hernandez-Velasco, J [BENSC, Hahn-Meitner Institut, Glienicker Strasse 100, D-14109 Berlin (Germany); Penc, B [M Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland); Sikora, W [Faculty of Physics and Nuclear Techniques, University of Mining and Metallurgy, Reymonta 19, 30-059 Cracow (Poland); Szytula, A [M Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland); Zygmunt, A [W Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Dorodna 2, 50-950 Wroclaw (Poland)

    2003-08-06

    Neutron diffraction studies of polycrystalline R{sub 3}Cu{sub 4}Sn{sub 4} (R = Tb, Dy, Ho, Er) intermetallic compounds with the orthorhombic Gd{sub 3}Cu{sub 4}Ge{sub 4}-type crystal structure indicate the existence of different magnetic structures. Rare earth atoms occupy two non-equivalent 2d and 4e sublattices. The rare earth magnetic moments order at low temperatures. For R = Tb and Dy the magnetic structures below the Neel temperature are described by the propagation vectors k = (0, 0, 1/2 + {delta}). In these compounds both rare earth sublattices order. For R = Ho the magnetic structure is more complicated. There are two vectors; one of them is k = (0, 1/2, 0) whereas the second one changes with temperature. For the Er compound there is the propagation vector k = (1/2, 1/2, 0) which describes the magnetic ordering in the 2d sublattice and at low temperatures is accompanied by the propagation vector k = (0, 0,{delta}) describing the ordering in the 4e sublattice.

  10. Magnetic structures of R{sub 3}Cu{sub 4}Ge{sub 4} (R=Tb, Dy, Ho, Er)

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzynska, E. E-mail: wawrzyn@castor.if.uj.edu.pl; Hernandez-Velasco, J.; Penc, B.; Szytula, A.; Zygmunt, A

    2003-08-01

    Neutron diffraction studies of polycrystalline R{sub 3}Cu{sub 4}Ge{sub 4} (R=Tb, Dy, Ho, Er) intermetallic compounds with the orthorhombic Gd{sub 3}Cu{sub 4}Ge{sub 4}-type crystal structure indicate complex magnetic structures. In these compounds the rare earth atoms occupy two nonequivalent 2d and 4e sublattices. For R=Tb and Er with decreasing temperature the magnetic moments in the 2d sublattice order first; the 4e sublattice magnetic moments order at lower temperatures. For R=Dy, Ho both sublattices order simultaneously although the magnetic moment values are different for each of them. In the compounds with R=Tb and Er a change of the magnetic structure, connected with the 2d sublattice, is observed near the Neel temperature. This is a transition from the commensurate structure, described by the propagation vector k=(0,((1)/(2)),0) at low temperatures to the incommensurate structure with k=(0,((1)/(2))+{delta},0) at higher temperatures (still below the Neel temperature)

  11. Magnetic structures of R{sub 3}Cu{sub 4}Si{sub 4} (R=Dy, Ho and Er)

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzynska, E. E-mail: e.w.@wp.pl; Hernandez-Velasco, J.; Penc, B.; Szytula, A. E-mail: szytula@if.uj.edu.pl

    2004-09-01

    Polycrystalline samples of R{sub 3}Cu{sub 4}Si{sub 4} (R=Dy, Ho, Er) intermetallics were studied with neutron diffraction methods. All of them crystallize in the orthorhombic structure of Gd{sub 3}Cu{sub 4}Ge{sub 4}-type and order antiferromagnetically at low temperatures. Magnetic moments localized at the rare earth atoms, that occupy two non-equivalent 2d and 4e sublattices, order simultaneously in Dy{sub 3}Cu{sub 4}Si{sub 4}. The order is described by the propagation vector k=(0,((1)/(2)),0) accompanied by k=(0,(1/2)+{delta},(1/2)+{delta}), {delta}=0.025(2). In Ho{sub 3}Cu{sub 4}Si{sub 4} two propagation vectors are needed to model the magnetic order. These are: k=((1/2),0.316(2),(1/2)) for the 4e sublattice, which disorders as the first when the temperature increases, and k=(0,(1/2),0) for the 2d sublattice. A similar situation is observed for Er{sub 3}Cu{sub 4}Si{sub 4} where the propagation vectors are: k=(0,1-{delta},0), {delta}=0.097(2) for the 4e sublattice, which disorders as the first with increasing temperature, and k=(0,(1/2)+{delta},0), {delta}=0.0015(6) for the 2d sublattice.

  12. Cytotoxic and genotoxic effect of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system in mice

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza-Lopez, Martha [Departamento de Medicina Nuclear, Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran, Delegacion Tlalpan, Mexico DF 14000 (Mexico); Ferro-Flores, Guillermina [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca, Ocoyoacac, Estado de Mexico, CP 52045 (Mexico); Arteaga de Murphy, Consuelo [Departamento de Medicina Nuclear, Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran, Delegacion Tlalpan, Mexico DF 14000 (Mexico)]. E-mail: consuelo_murphy@yahoo.com.mx; Morales-Ramirez, Pedro [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca, Ocoyoacac, Estado de Mexico, CP 52045 (Mexico); Piedras-Ross, Josefa [Departamento de Medicina Nuclear, Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran, Delegacion Tlalpan, Mexico DF 14000 (Mexico); Murphy-Stack, Eduardo [Hospital Santaelena, Mexico DF (Mexico); Hernandez-Oviedo, Omar [Escuela Superior de Fisica y Matematicas, IPN, Mexico DF (Mexico)

    2004-11-01

    Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. [{sup 166}Dy]Dy/{sup 166}Ho-ethylenediaminetetramethylene phosphonate (EDTMP) forms a stable in vivo generator system with selective skeletal uptake in mice; therefore, it could work as a potential and improved agent for marrow ablation. Induced bone marrow cytotoxicity and genotoxicity are determined by the reduction of reticulocytes (RET) and elevation of micronucleated reticulocyte (MN-RET) in peripheral blood and ablation by bone marrow histological studies. The aim of this study was to determine the bone marrow cytotoxic and genotoxic effect of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system in mice and to evaluate by histopathology its myeloablative potential. Enriched {sup 166}Dy{sub 2}O{sub 3} was irradiated and [{sup 166}Dy]DyCl{sub 3} was added to EDTMP in phosphate buffer (pH 8.0) in a molar ratio of 1:1.75. QC was determined by TLC. Dy-EDTMP complex was prepared the same way with nonirradiated dysprosium oxide. A group of BALB/c mice were intraperitoneally injected with the radiopharmaceutical and two groups of control animals were injected with the cold complex and with 0.9% sodium chloride, respectively. A blood sample was taken at the beginning of the experiments and every 48 h for 12 days postinjection. The animals were sacrificed, organs of interest taken out and the radioactivity determined. The femur was used for histological studies. Flow cytometry analysis was used to quantify the frequency of RET and MN-RET in the blood samples. The MCNP4B Monte Carlo computer code was used for dosimetry calculations. Radiochemical purity was 99% and the mean specific activity was 1.3 MBq/mg. The RET and MN-RET frequency were statistically different in the treatment at the end of the 12-day period demonstrating cytotoxicity and genotoxicity induced by the in vivo generator system. The

  13. Investigation of complexes with bone affinity using the In vivo generator system {sup 166} Dy/{sup 166} Ho; Investigacion de complejos con afinidad osea utilizando el Sistema de Generador in vivo {sup 166} Dy/{sup 166} Ho

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza L, M

    2006-07-01

    The importance of this original research lies in the fact that it has proven that the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system is a stable complex that can be used as a therapeutic radiopharmaceutical. Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. Bone-seeking radiopharmaceuticals such as {sup 166}Ho-DOTMP or {sup 153}Sm-DTMP, have been proposed for delivering ablative radiation doses to marrow in multiple myeloma and other hematological malignancies or have shown excellent results in palliative bone metastasis pain therapy, respectively. As lanthanides have similar chemical characteristics the phosphonate with bone affinity (EDTMP) labeled with Dy/Ho can be used for marrow ablation while causing minimal irradiation to normal organs. This in vivo generator system has not been previously reported. The aim of this research was to label EDTMP (ethylene diamine tetramethylene phosphonate) with {sup 166}Dy/{sup 166}Ho; to evaluate the in vitro and in vivo stability of both {sup 166}Dy-EDTMP and {sup 166}Ho-EDTMP complexes when the daughter {sup 166}Ho is formed as a dysprosium decay product; to determine the bone marrow cytotoxic and genotoxic effect in mice and to evaluate, by histopathology, the myeloablative potential of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system. {sup 166}Dy was obtained by neutron irradiation of enriched {sup 164}Dy{sub 2}O{sub 3} in a TRIGA Mark III reactor. Labeling was carried out in an aqueous phosphate medium at pH 8.0 by addition of {sup 166}DyCl{sub 3} to EDTMP at a molar ratio 1:1.75, with >99 % radiochemical purity, as determined by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). In vitro studies demonstrated that {sup 166}Dy/{sup 166}Ho-EDTMP is unstable after dilution in saline but stable in human serum with no translocation of the daughter nucleus

  14. Magnetic phase diagrams of R2RhIn8 (R = Tb, Dy, Ho, Er and Tm) compounds.

    Science.gov (United States)

    Cermák, P; Kratochvílová, M; Pajskr, K; Javorský, P

    2012-05-23

    We have grown and characterized single crystals of R(2)RhIn(8) (R=Tb, Dy, Ho, Er and Tm) compounds crystallizing in the tetragonal Ho(2)CoGa(8)-type crystal structure. Their magnetic properties were studied by specific heat and magnetization measurements. All the investigated compounds order antiferromagnetically with Néel temperatures of 43.6, 25.1, 10.9, 3.8 and 4.1 K, respectively. Magnetic phase diagrams were constructed.

  15. Magnetostructural phase transitions and magnetocaloric effect in Tb-Dy-Ho-Co-Al alloys with a Laves phase structure

    Science.gov (United States)

    Tereshina, I. S.; Chzhan, V. B.; Tereshina, E. A.; Khmelevskyi, S.; Burkhanov, G. S.; Ilyushin, A. S.; Paukov, M. A.; Havela, L.; Karpenkov, A. Yu.; Cwik, J.; Koshkid'ko, Yu. S.; Miller, M.; Nenkov, K.; Schultz, L.

    2016-07-01

    The influence of simultaneous substitution within the rare earth (R) and Co sublattices on the structural, magnetic, and magnetocaloric properties of the Laves phase RCo2-type compounds is studied. Main attention is devoted to the studies of the magnetostructural phase transitions and the transition types with respect to the alloy composition. Multicomponent alloys Tbx(Dy0.5Ho0.5)1-xCo2 and Tbx(Dy0.5Ho0.5)1-xCo1.75Al0.25 were prepared with the use of high purity metals. Majority of the Tbx(Dy0.5Ho0.5)1-xCo2 alloys exhibit magnetic transitions of the first-order type and a large magnetocaloric effect. The substitution of Al for Co in Tbx(Dy0.5Ho0.5)1-xCo2 increases the Curie temperature (TC) but changes the transition type from first-to the second-order. The discussion of the physical mechanisms behind the observed phenomena is given on the basis of the first principles electronic-structure calculations taking into account both the atomic disorder and the magnetic disorder effects at finite temperatures. The advantage of Al-containing materials is that sufficiently high magnetocaloric effect values are preserved at T > TC.

  16. YellowupconversionluminescenceinHo3+/Yb3+co-dopedGd2Mo3O9phosphor

    Institute of Scientific and Technical Information of China (English)

    孙家跃; 薛兵; 孙广超; 崔殿鹏

    2013-01-01

    The strong yellow upconversion (UC) light emission was observed in Ho3+/Yb3+co-doped Gd2Mo3O9 phosphor under the excitation of 980 nm diode laser. The phosphors were synthesized by the traditional solid-state reaction method. The structures of the samples were characterized by X-ray diffraction (XRD). Under 980 nm excitation, Ho3+/Yb3+co-doped Gd2Mo3O9 exhibited strong yellow UC emission based on the green emission near 541 nm generated by 5F4,5S2→5I8 transition and the strong red emission around 660 nm generated by 5F5→5I8 transition, which assigned to the intra-4f transitions of Ho3+ions. The doping concentrations of Ho3+and Yb3+were determined to be 0.01 mol Ho3+and 0.2 mol Yb3+for the strongest yellow emission. Then the dependence of UC emis-sion intensity on excitation power density showed that the green and red UC emissions were involved in two-photon process. The possible UC mechanisms for the strong yellow emission were also investigated. The result indicated that this material was a promis-ing candidate for the application in the yellow display field.

  17. Electrical transport and magnetic ordering in 2Ti3Ge4 (=Dy, Ho and Er) compounds

    Indian Academy of Sciences (India)

    R Nirmala; V Sankaranarayanan; K Sethupathi; A V Morozkin; T Geethakumary; Y Hariharan

    2002-05-01

    New 2Ti3Ge4 ( = Dy, Ho and Er) intermetallic compounds have been synthesized and characterized by X-ray diffraction and low temperature ac magnetic susceptibility, electrical resistivity and thermoelectric power measurements were carried out. The compounds crystallize in the parent, Sm5Ge4-type orthorhombic structure (space group Pnma) and lanthanide contraction is observed as one moves along the rare-earth series. The changeover from paramagnetic to antiferromagnetic phase happens at low temperatures and the ordering temperature scales with the de Gennes factor. The electrical resistivity is metallic with a negative curvature above 100 K. Thermopower displays a weak maximum at temperatures less than 50 K signifying the possible phonon and magnon drag effects.

  18. Competing $\\gamma$-rigid and $\\gamma$-stable vibrations in neutron rich Gd and Dy isotopes

    CERN Document Server

    Budaca, R

    2015-01-01

    An exactly separable version of the Bohr Hamiltonian which combines the $\\gamma$-stable and $\\gamma$-rigid axial vibration-rotation is used to describe the collective properties of few neutron rich transitional nuclei. The coupling between the two types of collective motion is managed through a rigidity parameter which also influences the geometry of the shape-phase space. While the $\\gamma$-angular part of the problem associated to axially symmetric shapes is treated within the small angles approximation and the stiff $\\gamma$ oscillation hypothesis, the $\\beta$ vibration is described by means of a Davidson potential. The resulting model have three free parameters not counting the scale and was successfully applied for the description of the collective spectra for few heavier isotopes of Gd and Dy. In both cases a critical nucleus was identified through a discontinuous behavior in respect to the rigidity parameter and relevant experimental observables.

  19. Subsolidus Phase Relations of the CaO-REOx-CuO Systems (RE = Eu, Tb, Dy, Ho, Er, Lu and Sc) at 900 °C in Air

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude

    2016-01-01

    The subsolidus phase relations of the CaO-REOx-CuO systems (RE = Eu, Tb, Dy, Ho, Er, Lu and Sc) were investigated in air at 900 °C. The pseudo-ternary sections with RE = Tb, Dy, Ho, Er and Lu have a similar structure. They have in common with the RE = Eu system a solid solution of Ca0.833−xRExCuO2...... in the other systems at 900 °C in air....

  20. Study of the magnetocaloric properties of the antiferromagnetic compounds RGa2 (R = Ce, Pr, Nd, Dy, Ho and Er).

    Science.gov (United States)

    dos Reis, R D; da Silva, L M; dos Santos, A O; Medina, A M N; Cardoso, L P; Gandra, F G

    2010-12-08

    Magnetocaloric properties of antiferromagnetic RGa(2) (R = Ce, Pr, Nd, Dy, Ho and Er) compounds have been reported. These systems present an antiferromagnetic transition below 15 K and a field induced metamagnetic transition from the antiferromagnetic to ferromagnetic state. Our results show that the character of the magnetic field induced transition along the series affects the magnetocaloric properties. For the compounds with R = Ho, Dy and Er both negative and positive magnetocaloric effect (MCE) were observed above μ(0)ΔH = 2 T where the rate between negative and positive MCE contributions depends on how the magnetic transitions occur in these compounds. The evaluated values of maximum magnetocaloric properties of RGa(2) compounds are similar to other potential magnetic refrigerant materials reported in the literature.

  1. Coherent phonons in pyrochlore titanates A2Ti2O7 (A= Dy, Gd, Tb): A phase transition in Dy2Ti2O7 at 110 K

    Science.gov (United States)

    Kamaraju, N.; Kumar, Sunil; Saha, Surajit; Singh, Surjeet; Suryanarayanan, R.; Revcolevschi, A.; Sood, A. K.

    2011-04-01

    We study the generation of coherent optical phonons in spin-frustrated pyrochlore single crystals Dy2Ti2O7, Gd2Ti2O7, and Tb2Ti2O7 using femtosecond laser pulses (65 fs, 1.57 eV) in degenerate time-resolved transmission experiments as a function of temperature from 4 to 296 K. At 4 K, two coherent phonons are observed at ~5.3 THz (5.0 THz) and ~9.3 THz (9.4 THz) for Dy2Ti2O7 (Gd2Ti2O7), whereas three coherent phonons are generated at ~5.0, 8.6, and 9.7 THz for Tb2Ti2O7. In the case of spin-ice Dy2Ti2O7, a clear discontinuity is observed in the linewidths of both the coherent phonons as well as in the phase of lower-energy coherent phonon mode, indicating a subtle structural change at 110 K. Another important observation is a phase difference of π between the modes in all the samples, thus suggesting that the driving forces behind the generation of these modes could be different in nature, unlike a purely impulsive or displacive mechanism.

  2. Magnetostructural phase transitions and magnetocaloric effect in Tb-Dy-Ho-Co-Al alloys with a Laves phase structure

    Energy Technology Data Exchange (ETDEWEB)

    Tereshina, I. S., E-mail: irina-tereshina@mail.ru [Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Baikov Institute of Metallurgy and Material Sciences, Russian Academy of Sciences, Moscow 119991 (Russian Federation); International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw 53-421 (Poland); Chzhan, V. B. [Baikov Institute of Metallurgy and Material Sciences, Russian Academy of Sciences, Moscow 119991 (Russian Federation); International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw 53-421 (Poland); National University of Science and Technology “MISIS”, Moscow 119049 (Russian Federation); Tereshina, E. A. [Institute of Physics CAS, Prague 18221 (Czech Republic); Khmelevskyi, S. [Center for Computational Materials Science, IAP, Vienna University of Technology, Vienna A-1040 (Austria); Burkhanov, G. S. [Baikov Institute of Metallurgy and Material Sciences, Russian Academy of Sciences, Moscow 119991 (Russian Federation); Ilyushin, A. S. [Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Complex Research Institute named after Kh. I. Ibragimov, Russian Academy of Sciences, Groznyi 364906 (Russian Federation); Paukov, M. A.; Havela, L. [Faculty of Mathematics and Physics, Charles University, Prague 12116 (Czech Republic); Karpenkov, A. Yu. [Physics Faculty, Tver State University, Tver 170100 (Russian Federation); Department of Physics, Chelyabinsk State University, Chelyabinsk 454001 (Russian Federation); Cwik, J.; Koshkid' ko, Yu. S.; Miller, M. [International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw 53-421 (Poland); Nenkov, K.; Schultz, L. [Leibniz-Institut fur Festkorper- und Werkstoffforschung, Dresden D-01171 (Germany)

    2016-07-07

    The influence of simultaneous substitution within the rare earth (R) and Co sublattices on the structural, magnetic, and magnetocaloric properties of the Laves phase RCo{sub 2}-type compounds is studied. Main attention is devoted to the studies of the magnetostructural phase transitions and the transition types with respect to the alloy composition. Multicomponent alloys Tb{sub x}(Dy{sub 0.5}Ho{sub 0.5}){sub 1−x}Co{sub 2} and Tb{sub x}(Dy{sub 0.5}Ho{sub 0.5}){sub 1−x}Co{sub 1.75}Al{sub 0.25} were prepared with the use of high purity metals. Majority of the Tb{sub x}(Dy{sub 0.5}Ho{sub 0.5}){sub 1−x}Co{sub 2} alloys exhibit magnetic transitions of the first-order type and a large magnetocaloric effect. The substitution of Al for Co in Tb{sub x}(Dy{sub 0.5}Ho{sub 0.5}){sub 1−x}Co{sub 2} increases the Curie temperature (T{sub C}) but changes the transition type from first-to the second-order. The discussion of the physical mechanisms behind the observed phenomena is given on the basis of the first principles electronic-structure calculations taking into account both the atomic disorder and the magnetic disorder effects at finite temperatures. The advantage of Al-containing materials is that sufficiently high magnetocaloric effect values are preserved at T > T{sub C}.

  3. Raman Active Phonons in RCoO3 (R=La, Ce, Pr, Nd, Sm, Eu, Gd, and Dy) Perovskites

    Institute of Scientific and Technical Information of China (English)

    WANG Wei-Ran; XU Da-Peng; SU Wen-Hui; DING Zhan-Hui; XUE Yan-Feng; SONG Geng-Xin

    2005-01-01

    @@ We examine RCoO3 (R=La, Ce, Pr, Nd, Sm, Eu, Gd, and Dy) perovskites prepared with the solid-state reaction method by Raman spectroscopy, and report the Raman active phonons in the RCoO3 perovskites crystallized in cubic symmetry for RCoO3 (R=La, Ce, Pr and Nd) and orthorhombic symmetry for RCoO3 (R=Sm, Eu, Gd,and Dy). It is found that the Raman spectra of RCoO3 perovskites are strongly dependent on the ionic radius.of the rare earth elements, and the frequency shift of the most intense modes of the orthorhombic samples are correlated with some structural parameters such as Co-O bond distances, ionic radius of the rare earth elements and Jahn-Teller distortion. It is clear that Raman spectroscopy has the advantage of sensitivity to structure distortion and oxygen motion.

  4. Structural and optical characteristics of Ce, Nd, Gd, and Dy-doped Al2O3 thin films

    Science.gov (United States)

    Varpe, Ashwini S.; Deshpande, Mrinalini D.

    2017-07-01

    We present the optical properties of rare earth (RE)-doped Al_2O_3 thin films and discuss their possible use in applications like gate dielectric material and in coating industry. Aluminum oxide films doped with RE elements such as Ce, Nd, Gd, and Dy are synthesized on glass substrate using ultrasonic spray pyrolysis technique at 400°C. The concentration of rare earth element is varied from 0.5 to 5 mol% in 0.1 M solution of Al2O3. The X-ray diffraction analysis indicates that the thin films deposited with and without rare earth doping have an amorphous structure. Further, the optical properties of RE-doped Al2O3 thin films are studied by using UV-visible spectroscopy and photoluminescence measurement. The band gap is found to be 4.06 eV for Al2O3 thin film. A small blue shift is seen in the optical spectra of RE-doped samples as compared to undoped Al2O3 film. Dielectric constant of alumina thin film increases with doping of Gd and Dy while it decreases with Ce and Nd doping. Concentration quenching effects are observed in the photoluminescence spectra of Ce, Nd, Gd, and Dy-doped Al_2O_3 films. Among all these RE-doped Al2O3 thin films, Gd and Dy-doped Al2O3 films exhibit a potential for the construction of dielectric gate in transistors or as a coating material in the semiconductor industry.

  5. Structural and optical characteristics of Ce, Nd, Gd, and Dy-doped $\\rm{Al_{2}O_{3}}$ thin films

    Indian Academy of Sciences (India)

    ASHWINI S VARPE; MRINALINI D DESHPANDE

    2017-07-01

    We present the optical properties of rare earth (RE)-doped $\\rm{Al_{2}O_{3}}$ thin films and discuss their possible use in applications like gate dielectric material and in coating industry. Aluminum oxide films doped with RE elements such as Ce, Nd, Gd, and Dy are synthesized on glass substrate using ultrasonic spray pyrolysis technique at 400$^{\\circ}$C. The concentration of rare earth element is varied from 0.5 to 5 mol% in 0.1 M solution of $\\rm{Al_{2}O_{3}}$. The X-ray diffraction analysis indicates that the thin films deposited with and without rare earth doping have an amorphous structure. Further, the optical properties of RE-doped $\\rm{Al_{2}O_{3}}$ thin films are studied by using UV–visible spectroscopy and photoluminescence measurement. The band gap is found to be 4.06eV for $\\rm{Al_[2}O_{3}}$ thin film. A small blue shift is seen in the optical spectra of RE-doped samples as compared to undoped $\\rm{Al_[2}O_{3}}$ film. Dielectric constant of alumina thin film increases with doping of Gd and Dy while it decreases with Ce and Nd doping. Concentration quenching effects are observed in the photoluminescence spectra of Ce, Nd, Gd, and Dy-doped $\\rm{Al_[2}O_{3}}$ films. Among all these RE-doped $\\rm{Al_[2}O_{3}}$ thin films, Gd and Dy-doped $\\rm{Al_[2}O_{3}}$ films exhibit a potential for the construction of dielectric gate in transistors or as a coating material in the semiconductor industry.

  6. Genotoxic and cytotoxic damage by the therapeutic radiopharmaceutical [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP as in vivo generator system; Dano genotoxico y citotoxico por el radiofarmaco terpeutico [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP como sistema de generador in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza L, M.; Piedras R, J. [Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran. Vasco. de Quiroga 15, 14000 Mexico D.F. (Mexico); Ferro F, G.; Morales R, P. [ININ, Km. 36.5 Carretera Mexico-Toluca, Ocoyoacac, 52045 Estado de Mexico (Mexico); Murphy S, E. [Hospital Santaelena, Mexico D.F. (Mexico); Hernandez O, O. [Escuela Superior de Fisica y Matematicas, IPN, Mexico D.F. (Mexico)

    2005-07-01

    In patients with leukemias and multiple myeloma, the cure can be obtained to inclination of a bone marrow transplant (m.o.), for that which one is used a combination of external radiotherapy and chemotherapy with the consequent toxicity to healthy organs. The complex [{sup 166}Dy]Dy/{sup 166}Ho-ethylenediaminetetramethylenephosphonate ([{sup 166}Dy]Dy/{sup 166}Ho-EDTMP) it forms a generator system in vivo stable with bony selective likeness in mice therefore, this it could work as a therapeutic radiopharmaceutical for bone marrow ablation. The objective of this original work was to determine the genotoxic and cytotoxic damage produced by the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP like a generator system in vivo by means of the reticulocytes reduction (RET) and micronucleus elevation in reticulocytes (RET-MN) in peripheral blood and to evaluate its myeloablative potential for histopathologic studies. It was irradiated {sup 166}Dy{sub 2}O{sub 3} enriched and it was add in form {sup 166}DyCI{sub 3} to the EDTMP in a softening media of phosphates (pH 8), the optimal molar relationship {sup 166}Dy: EDTMP was 1.7:1 and the radiochemical purity was evaluated by ITLC. The Dy:EDTMP complexes, non radioactive, its were prepared in the same way with non irradiated dysprosium oxide. A group of BALB/c mice was injected intraperitoneally with the radiopharmaceutical and two groups of control mice were injected with the non radioactive complex and with sodium chloride 0.9% respectively. Before injecting each one of the solutions it was take a basal sample of peripheral blood of the mouse tail and each 48 h post-injection during 12 d. The animals were sacrificed to obtain the organs of interest and to determine the radioactivity in each one. The femur was used for the histopathologic studies. The quantification of the frequency of RET and RET-MN was carried out by flow cytometry of the sanguine samples and the Monte Carlo code MCNP4B for the dosimetry calculations was used. The

  7. Energy transfer and tunable multicolor emission and paramagnetic properties of GdF3:Dy(3+),Tb(3+),Eu(3+) phosphors.

    Science.gov (United States)

    Guan, Hongxia; Sheng, Ye; Xu, Chengyi; Dai, Yunzhi; Xie, Xiaoming; Zou, Haifeng

    2016-07-20

    A series of Dy(3+), Tb(3+), Eu(3+) singly or doubly or triply doped GdF3 phosphors were synthesized by a glutamic acid assisted one-step hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and photoluminescence (PL) spectroscopy. The results show that the synthesized samples are all pure GdF3. The obtained samples have a peanut-like morphology with a diameter of about 270 nm and a length of about 600 nm. Under UV excitation, GdF3:Dy(3+), GdF3:Tb(3+) and GdF3:Eu(3+) samples exhibit strong blue, green and red emissions, respectively. By adjusting their relative doping concentrations in the GdF3 host, the different color hues of green and red light are obtained by co-doped Dy(3+), Tb(3+) and Tb(3+), Eu(3+) ions in the GdF3 host, respectively. Besides, there exist two energy transfer pairs in the GdF3 host: (1) Dy(3+) → Tb(3+) and (2) Tb(3+) → Eu(3+). More significantly, in the Dy(3+), Tb(3+), and Eu(3+) tri-doped GdF3 phosphors, white light can also be achieved upon excitation of UV light by adjusting the doping concentration of Eu(3+). In addition, the obtained samples also exhibit paramagnetic properties at room temperature (300 K) and low temperature (2 K). It is obvious that multifunctional Dy(3+), Tb(3+), Eu(3+) tri-doped GdF3 materials including tunable multicolors and intrinsic paramagnetic properties may have potential applications in the field of full-color displays.

  8. Crystal Structures of Dy2(WO4)3 and GdY(WO4)3

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Two compounds, Dy2(WO4)3 and GdY(WO4)3; were synthesized by using the standard solid state reaction tech-nique. The crystal structure was determined by powder X-ray diffraction and Rietveld refinement method. It is found thatboth compounds have Eu2(WO4)3-type monoclinic structure, with space group C 2/c, Z = 4. The unit cell parameters ofDy2(WO4)3 are a = 0.75981(1) nm, b = 1.13220(1) nm, c = 1.13254(1) nm, and β= 109.8001(3)°, and those of GdY(WO4)3are a = 0.76175(1) nm, b = 1.13543(1) nm, c = 1.13496(2) nm, and β= 109.8015(13)°. Each W atom has four oxygen near-est neighbors, while each rare-earth atom is surrounded by eight oxygen atoms. WO4 tetrahedra share their four verticeswith REO8 (RE = Dy, Gd, or Y) trigondodecahedra and some REO8 trigondodecahedra share an edge with each other. Thephase transition and the magnetic properties were investigated by differential thermal analysis (DTA) and dc superconduct-ing quantum interference device (SQUID) magnetometer.

  9. Rare Earth Dopant (Nd, Gd, Dy, and Er Hybridization in Lithium Tetraborate

    Directory of Open Access Journals (Sweden)

    Tony D. Kelly

    2014-05-01

    Full Text Available The four dopants (Nd, Gd, Dy, and Er substitutionally occupy the Li+ sites in lithium tetraborate (Li2B4O7: RE glasses as determined by analysis of the extended X-ray absorption fine structure. The dopants are coordinated by 6-8 oxygen at a distance of 2.3 to 2.5 Å, depending on the rare earth. The inverse relationship between the RE¬ O coordination distance and rare earth (RE atomic number is consistent with the expected lanthanide atomic radial contraction with increased atomic number. Through analysis of the X-ray absorption near edge structure, the rare earth dopants adopt the RE3+ valence state. There are indications of strong rare earth 5d hybridization with the trigonal and tetrahedral formations of BO3 and BO4 based on the determination of the rare earth substitutional Li+ site occupancy from the X-ray absorption near edge structure data. The local oxygen disorder around the RE3+ luminescence centers evident in the structural determination of the various glasses, and the hybridization of the RE3+ dopants with the host may contribute to the asymmetry evident in the luminescence emission spectral lines. The luminescence emission spectra are indeed characteristic of the expected f-to-f transitions; however, there is an observed asymmetry in some emission lines.

  10. Mössbauer studies and enhanced electrical properties of R (R=Sm, Gd and Dy) doped Ni ferrite

    Science.gov (United States)

    Inbanathan, S. S. R.; Vaithyanathan, V.; Arout Chelvane, J.; Markandeyulu, G.; Kamala Bharathi, K.

    2014-03-01

    Structural, Mössbauer studies and improved electrical characteristics of Sm, Gd and Dy doped Ni ferrite materials in comparison to that of pure NiFe2O4 are reported. Pure NiFe2O4 crystallizes in inverse spinel phase without any impurity phase. NiFe1.925Sm0.075O4, NiFe1.925Gd0.075O4 and NiFe1.925Dy0.075O4 compounds crystallize in the cubic inverse spinel phase with a very small amount of RFeO3 as additional phase. The back scattered electron imaging analysis indicates the primary and secondary phase formation in NiFe1.925Sm0.075O4, NiFe1.925Gd0.075O4 and NiFe1.925Dy0.075O4 compounds. The room temperature DC resistivity values of NiFe2O4, NiFe1.925Sm0.075O4, NiFe1.925Gd0.075O4 and NiFe1.925Dy0.075O4 compounds are found to be 17×107 Ω cm, 162×107 Ω cm, 171×107 Ω cm and 305×107 Ω cm respectively. The AC resistivity values (at 1 KHz) of NiFe2O4, NiFe1.925Sm0.075O4, NiFe1.925Gd0.075O4 and NiFe1.925Dy0.075O4 materials are 10×105 Ω cm, 77×105 Ω cm, 147×105 Ω cm and 251×105 Ω cm, respectively. Temperature dependent electrical resistivity curves reveal two different types of conduction mechanisms. The hyperfine parameters viz., the hyperfine magnetic field, the isomer shift and the quadrupole splitting confirms the substitutions of R3+ ions at B site and their effects on superexchange interactions and structural distortion. The enhanced electrical resistivity of rare earth doped Ni ferrite suggest that tuning properties for desired high frequency applications can be achieved by controlling the doping element and their amount.

  11. Preparation and Magnetostriction of Tb0.22Dy0.48HO0.35Fe2 Alloys

    Institute of Scientific and Technical Information of China (English)

    Jiang Minhong

    2007-01-01

    Tb0.22Dy0.48Ho0.35Fe2 quaternary alloys are prepared by melting-top casting-annealing process. X-ray diffraction reveals that the alloy is single phase polycrystalline alloy with MgCu2 type cubic Laves phase structure, and (511) preferred orientation occurs in its. The magnetostriction measurements are carried out at room temperature using standard strain gauge technique in magnetic fields up to 400kA·m-1. The results show that when the magnetic field, H, is 90kA·m-1, the magnetostriction, λ ,of Tb0.22Dy0.48Ho0.35Fe2 quaternary alloys is 260×10-6, and when the H is 210kA·m-1, the λ is 438×10-6. When the H is 400kA·m-1, the λ is up to the saturation value, 538×10-6. As compared with TbDyFe ternary alloys, the λ of the quaternary alloy is significantly higher when the H is less than or equal to 210kA·m-1. When the H is 120kA·m-1,the λ of the alloy is 333×10-6,70×10-6 more than the ternary alloy. Research results and mechanism are discussed.

  12. Measurement of cross sections producing short-lived nuclei by 14 MeV neutron. Br, Te, Dy, Ho, Yb

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, H.; Matsumoto, T.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Iida, T.; Takahashi, A.

    1997-03-01

    Nine neutron activation cross sections producing the nuclei with half-lives between 2 min and 57 min have been measured at energy range between 13.4 and 14.9 MeV for Br, Te, Dy, Ho, Yb. The cross sections of {sup 81}Br(n,p){sup 81m}Se, {sup 128}Te(n,p){sup 128m}Sb, {sup 128}Te(n,{alpha}){sup 125m}Sn, {sup 164}Dy(n,p){sup 164}Tb, {sup 165}Ho(n,{alpha}){sup 162}Tb, {sup 176}Yb(n,p){sup 176}Tm were newly obtained at the six energy points between 13.4-14.9 MeV, although the previous results have been obtained at one energy point. {sup 79}Br(n,2n){sup 78}Br, {sup 164}Dy(n,p){sup 164}Tb are compared with evaluated data of JENDL-3.2. The evaluations for these reactions agree reasonably well with experimental results. The cross sections of (n,p) reaction are compared with systematics by Kasugai et. al. The systematics agrees with experimental results. (author)

  13. Effects of Nd, Sm, Gd, Dy, Er Dopant on Electrical Properties of BaTiO3 Ceramics

    Institute of Scientific and Technical Information of China (English)

    Hao Sue; Wei Yongde; Xing Xiaoxu

    2004-01-01

    BaTiO3 ceramics doped with various quantities of Nd2O3, Sm2O3, Gd2O3, Dy2O3 and Er2O3 were prepared respectively ( the adulterate concentrations were 0. 001,0. 002, 0. 003, 0.005, 0. 007 mol fraction) through a sol-gel method and their electrical properties were researched. It is found that each adulteration of Nd2O3, Sm2O3 Gd2O3,Dy2O3 and Er2O3 all can make the resistivity of BaTiO3 ceramics decline , especially Sm2O3 and Gd2O3. When the addition of Sm2O3 is 0. 001 mol, the resistivity is the smallest, declining from 4.0 × 1012 to 6.5 × 103 Ω different kind of rare earth exhibits different regularity. The grain resistance of BaTiO3 ceramics doped with Sm2O3 or Gd2O3 exhibits a NTC effect, at the same time the grain boundary resistance has a PTC effect, and the grain boundary resistance is much larger than the grain resistance, so the PTC effects of BaTiO3 ceramics doped with Sm2O3 or Gd2O3 originate from the grain boundary. The additions of Nd2O3 , Gd2O3 or Er2O3 make the dielectric constant and the dielectric loss of BaTiO3 ceramics change evidently, especially Nd2O3. The dielectric constant is larger than that of pure BaTiO3 ceramics, on the other hand, the dielectric loss is much lower, which is useful in capacitor fields.

  14. White light emitting LaGdSiO5:Dy3+ nanophosphors for solid state lighting applications

    Science.gov (United States)

    Ogugua, Simon N.; Swart, Hendrik C.; Ntwaeaborwa, Odireleng M.

    2016-01-01

    Powdered dysprosium (Dy3+) doped Lanthanum gadolinium oxyorthosilicate (LaGdSiO5) mixed phosphors were synthesized using urea-assisted solution combustion method. The X-ray diffractometer analysis showed that the samples crystalized in the pure monoclinic mixed phase of LaGdSiO5. The crystallite size and the lattice strain calculated from the X-ray diffraction peaks using Williamson-Hall equation varied from 12 nm to 16 nm and 1.6 ×10-2 to 2.43 ×10-2 respectively. The photoluminescence (PL) emission spectra recorded using 425, 454 and 475 nm excitation wavelengths exhibit characteristic similar to the YAG:Ce phosphor pumped InGaN LED system, by absorbing portion of the excitation energy and re-emitting it. The emission spectra were characterized by radiative recombination at 425, 454, 475, 485 and 575 nm depending on the excitation wavelength. These emission line are ascribed to the f→f transitions of Dy3+. The peak intensity and hence the color of the emitted visible light were dependent on the concentration of Dy3+. The International Commission on Illumination (CIE) color coordinates of (0.336, 0.313) and (0.359, 0.361) were obtained for Dy3+ molar concentration of 0.05 and 3.0 mol% when the emission was monitored using 454 nm and 475 nm respectively. The band gap measured from the reflectance curve using Tauc plot initially decreased with increasing Dy3+ concentration, but at higher concentration, it started to increase. These materials were evaluated for solid state lighting application.

  15. Magnetic remanence in Yb14-xRExMnSb11 (RE=Tb, Dy, Ho) single crystals

    Science.gov (United States)

    Grebenkemper, Jason H.; Hu, Yufei; Abdusalyamova, M. N.; Makhmudov, F. A.; Kauzlarich, Susan M.

    2016-06-01

    Single crystals of Yb14-xRExMnSb11 (x~0.1, 0.4; RE = Tb, Dy, Ho) have been prepared as a solid solution by Sn flux reactions of the elements. They crystallize in the Ca14AlSb11 structure type in the I41/acd space group. The RE3+preferentially substitutes on the Yb(1) site which is the smallest volume Yb containing polyhedron. In the case of Ho3+, a small amount of Ho3+ also substitutes on the Yb(4) site. The ferromagnetic ordering temperature of Yb14MnSb11 is reduced from 53 K to 41 K as x increases and dependent on the identity of the RE. This is attributed to the reduction in carriers and reduced screening of the Mn2+ local moment. The effective moments, μeff, agree well with the calculated moments assuming the RE substitutes as a trivalent cation. The largest coercive field is observed for RE = Dy (1000 Oe). For the maximum x of Yb14-xRExMnSb11 there are enough carriers for the Ruderman-Kittel-Kasuya-Yosida (RKKY) mechanism of magnetic coupling via conduction electrons to still be valid in describing the ferromagnetic ordering.

  16. High-pressure syntheses and characterization of the rare-earth fluoride borates RE{sub 2}(BO{sub 3})F{sub 3} (RE = Tb, Dy, Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Hinteregger, Ernst; Pitscheider, Almut; Wurst, Klaus; Heymann, Gunter; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie; Enders, Michael [Innsbruck Univ. (Austria). Inst. fuer Pharmazie

    2013-11-15

    The new rare-earth fluoride borates RE{sub 2}(BO{sub 3})F{sub 3} (RE = Tb, Dy, Ho) were synthesized under high-pressure/high-temperature conditions of 1.5 GPa/1200 C for Tb{sub 2}(BO{sub 3})F{sub 3} and 3.0 GPa/900 C for Dy{sub 2}(BO{sub 3})F{sub 3} and Ho{sub 2}(BO{sub 3})F{sub 3} in a Walker-type multianvil apparatus from the corresponding rare-earth sesquioxides, rare-earth fluorides, and boron oxide. The single-crystal structure determinations revealed that the new compounds are isotypic to the known rare-earth fluoride borate Gd{sub 2}(BO{sub 3})F{sub 3}. The new rare-earth fluoride borates crystallize in the monoclinic space group P2{sub 1}/c (Z = 8) with the lattice parameters a = 16.296(3), b = 6.197(2), c = 8.338(2) A, {beta} = 93.58(3) for Tb{sub 2}(BO{sub 3})F{sub 3}, a = 16.225(3), b = 6.160(2), c = 8.307(2) A, {beta} = 93.64(3) for Dy{sub 2}(BO{sub 3})F{sub 3}, and a = 16.189(3), b = 6.124(2), c = 8.282(2) A, {beta} = 93.69(3) for Ho{sub 2}(BO{sub 3})F{sub 3}. The four crystallographically different rare-earth cations (CN = 9) are surrounded by oxygen and fluoride anions. All boron atoms form isolated trigonal-planar [BO{sub 3}]{sup 3-} groups. The six crystallographically different fluoride anions are in a nearly planar coordination by three rare-earth cations. (orig.)

  17. 热处理对Gd0.6Dy0.4Co2和Gd0.6Dy0.4Co1.9Al0.1合金磁热性能的影响%Effect of Heat-treatment on the Magnetocaloric Properties of Gd0.6Dy0.4Co2 and Gd0.6Dy0.4Co1.9Al0.1

    Institute of Scientific and Technical Information of China (English)

    吴卫; 于越

    2010-01-01

    用真空电弧熔炼炉制备Gd0.6Dy0.4Co2和Gd0.6Dy0.4Co1.9Al0.1合金,在900℃下进行4天、7天的热处理后,对其铸态和热处理态的相结构、居里温度、绝热温变、磁熵变等进行了研究.结果表明:经过7天的热处理后合金晶体结构基本变为单相GdCo2结构.热处理的结果使合金的最大绝热温变值比铸态合金有所升高,磁熵变值比铸态合金提高53.2%和33.1%,居里温度略有降低,说明热处理能有效提高该系列合金的磁热性能.

  18. Effects of morphology on the structural and photoluminescence properties of co-precipitation derived GdVO4:Dy3+

    Science.gov (United States)

    Kumari, Puja; Manam, J.

    2016-10-01

    Herein, Dy3+ doped GdVO4 samples with various morphologies were prepared by the co-precipitation method at low temperature, and the effects of different morphologies on the structural and optical behaviors have been reported. The obtained samples were stabilized to the stable tetragonal structure. The IR and FESEM study were carried out to see the vibrational bonds position and surface morphology. At present PL, PLE, diffuse reflectance and decay curves have been discussed in detail. The morphology dependent photoluminescence studies were resulted to a suitable sample for the lighting and display applications.

  19. Fabrication, photoluminescence, and potential application in white light emitting diode of Dy3+-Tm3+ doped transparent glass ceramics containing GdSr2F7 nanocrystals

    Science.gov (United States)

    Wang, X. F.; Yan, X. H.; Bu, Y. Y.; Zhen, J.; Xuan, Y.

    2013-08-01

    Dy3+-Tm3+ doped transparent glass ceramics containing GdSr2F7 nanocrystals were fabricated successfully by a melt-quenching method and subsequent heating. X-ray diffraction and transmission electron microscopy analyses show that tetragonal GdSr2F7 nanocrystals are homogeneously precipitated among the borosilicate glass matrix. If excited with 354 nm UV light, the photoluminescence spectrum of Dy3+ single-doped transparent glass ceramics shows white-light emission. With doping of Tm3+, the overall emission color of Tm3+-Dy3+ co-doped transparent glass ceramics can be tuned from white to blue through energy transfer between Dy3+ and Tm3+. CIE chromaticity and color temperature measurements show that the resulting TGCS may be a candidate as a white LED material pumped by a UV InGaN chip.

  20. Crystal field effects in the intermetallic R Ni3Ga9 (R =Tb , Dy, Ho, and Er) compounds

    Science.gov (United States)

    Silva, L. S.; Mercena, S. G.; Garcia, D. J.; Bittar, E. M.; Jesus, C. B. R.; Pagliuso, P. G.; Lora-Serrano, R.; Meneses, C. T.; Duque, J. G. S.

    2017-04-01

    In this paper, we report temperature-dependent magnetic susceptibility, electrical resistivity, and heat-capacity experiments in the family of intermetallic compounds R Ni3Ga9 (R = Tb, Dy, Ho, and Er). Single-crystalline samples were grown using Ga self-flux method. These materials crystallize in a trigonal ErNi3Al9 -type structure with space group R 32 . They all order antiferromagnetically with TNK . The anisotropic magnetic susceptibility presents large values of the ratio χeasy/χhard indicating strong crystalline electric-field (CEF) effects. The evolution of the crystal-field scheme for each R was analyzed in detail by using a spin model including anisotropic nearest-neighbor Ruderman-Kittel-Kasuya-Yosida interaction and the trigonal CEF Hamiltonian. Our analysis allows one to understand the distinct direction of the ordered moments along the series—the Tb-, Dy-, and Ho-based compounds have the ordered magnetic moments in the easy ab plane and the Er sample magnetization easy axis is along the c ̂ direction.

  1. Synthesis and luminescence properties of BaTiO3:RE (RE = Gd3+, Dy3+, Tb3+, Lu3+) phosphors

    Indian Academy of Sciences (India)

    Esra Korkmaz; Nilgun Ozpozan Kalaycioglu

    2012-11-01

    Gd3+, Dy3+, Tb3+ and Lu3+ doped BaTiO3-based phosphors were synthesized with modified solidstate technique at 1000 °C. The optimization of reaction conditions were carried out by thermogravimetry and differential thermal analysis methods (DTA/TG). The reaction products obtained in an air atmosphere were characterized by X-ray powder diffraction (XRD). Surface and elemental analyses were performed by using an SEM instrument. The excitation and emission spectra were recorded by photoluminescence spectrophotometer (PL). The thermoluminescence (TL) properties of BaTiO3 samples doped with Gd3+, Dy3+, Tb3+ and Lu3+ were investigated.

  2. Synthesis and Photophysical Properties of Dy3+ and Gd3+ Polymeric Complexes with Functionalized Polybenzimidazole Containing β-Diketone Side Group

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The polymeric ligand PBIa (functionalized polybenzimidazole containing β-diketone side group) was successfully synthesized via the reaction of polybenzimidazole (PBI) with 3-Br-acetylacetone in DMSO solvent using NaH as the deprotonation reagent. Its corresponding polymeric complexes of Dy3+ and Gd3+ were prepared and characterized by FT-IR, 1H NMR, molar conductance measurements, and thermal analysis. The photoluminescence properties and the probable mechanism of the Dy and Gd complexes were studied. The measurement and analysis of the thermal properties showed that these were thermal stable.

  3. Mössbauer studies and enhanced electrical properties of R (R=Sm, Gd and Dy) doped Ni ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Inbanathan, S.S.R. [Post Graduate and Research Department of Physics, The American College, Madurai 625002 (India); Vaithyanathan, V. [Research and Development Centre, Bharathiar University, Coimbatore 641046 (India); Arout Chelvane, J. [Advanced Magnetics Laboratory, Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500058 (India); Markandeyulu, G. [Advanced Magnetic Materials Laboratory (AMMLa), Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Kamala Bharathi, K., E-mail: kkamalabharathi@gmail.com [NCRL Laboratory, Department of Materials Science and Engineering, KAIST, Daejeon 305701 (Korea, Republic of)

    2014-03-15

    Structural, Mössbauer studies and improved electrical characteristics of Sm, Gd and Dy doped Ni ferrite materials in comparison to that of pure NiFe{sub 2}O{sub 4} are reported. Pure NiFe{sub 2}O{sub 4} crystallizes in inverse spinel phase without any impurity phase. NiFe{sub 1.925}Sm{sub 0.075}O{sub 4,} NiFe{sub 1.925}Gd{sub 0.075}O{sub 4} and NiFe{sub 1.925}Dy{sub 0.075}O{sub 4} compounds crystallize in the cubic inverse spinel phase with a very small amount of RFeO{sub 3} as additional phase. The back scattered electron imaging analysis indicates the primary and secondary phase formation in NiFe{sub 1.925}Sm{sub 0.075}O{sub 4,} NiFe{sub 1.925}Gd{sub 0.075}O{sub 4} and NiFe{sub 1.925}Dy{sub 0.075}O{sub 4} compounds. The room temperature DC resistivity values of NiFe{sub 2}O{sub 4}, NiFe{sub 1.925}Sm{sub 0.075}O{sub 4,} NiFe{sub 1.925}Gd{sub 0.075}O{sub 4} and NiFe{sub 1.925}Dy{sub 0.075}O{sub 4} compounds are found to be 17×10{sup 7} Ω cm, 162×10{sup 7} Ω cm, 171×10{sup 7} Ω cm and 305×10{sup 7} Ω cm respectively. The AC resistivity values (at 1 KHz) of NiFe{sub 2}O{sub 4}, NiFe{sub 1.925}Sm{sub 0.075}O{sub 4}, NiFe{sub 1.925}Gd{sub 0.075}O{sub 4} and NiFe{sub 1.925}Dy{sub 0.075}O{sub 4} materials are 10×10{sup 5} Ω cm, 77×10{sup 5} Ω cm, 147×10{sup 5} Ω cm and 251×10{sup 5} Ω cm, respectively. Temperature dependent electrical resistivity curves reveal two different types of conduction mechanisms. The hyperfine parameters viz., the hyperfine magnetic field, the isomer shift and the quadrupole splitting confirms the substitutions of R{sup 3+} ions at B site and their effects on superexchange interactions and structural distortion. The enhanced electrical resistivity of rare earth doped Ni ferrite suggest that tuning properties for desired high frequency applications can be achieved by controlling the doping element and their amount. - Highlights: • Substitution of R ions for Fe enhances the electrical resistivity of Ni ferrite. • BSE and SEM

  4. Effect of Tb and Al substitution within the rare earth and cobalt sublattices on magnetothermal properties of Dy0.5Ho0.5Co2

    Science.gov (United States)

    Chzhan, V. B.; Tereshina, E. A.; Mikhailova, A. B.; Politova, G. A.; Tereshina, I. S.; Kozlov, V. I.; Ćwik, J.; Nenkov, K.; Alekseeva, O. A.; Filimonov, A. V.

    2017-06-01

    The effect of Tb and Al substitution within the rare earth and cobalt sublattices on structural and magnetothermal properties of Dy0.5Ho0.5Co2 has been studied. Multicomponent Laves phase alloys Tbx(Dy0.5Ho0.5)1-xCo2-yAly (x = 0, 0.3, 0.4, 0.5; y = 0, 0.25) synthesized using high-purity metals have been studied using X-ray diffraction analysis, heat capacity and magnetocaloric measurements. Dy0.5Ho0.5Co2 has a first order phase transition at the Curie temperature TC ≈ 110 K. Both Tb and Al substitution leads to increase of the TC. The increasing Tb content leads to the decreases slightly the MCE and all the transitions near the Curie temperature are of the first order. As for the Al-containing compounds, MCE measurements show that the phase transition type changes from the first to the second-order. The advantage of Tbx(Dy0.5Ho0.5)1-xCo1.75Al0.25 as compared with Al-free alloys is 'table-like' behavior of MCE.

  5. Performance characteristics of a magnetic Ericsson refrigeration cycle using Gd{sub x}Dy{sub 1−x} as the working substance

    Energy Technology Data Exchange (ETDEWEB)

    Diguet, Gildas, E-mail: diguet_gildas@yahoo.fr; Lin, Guoxing, E-mail: gxlin@xmu.edu.cn; Chen, Jincan, E-mail: jcchen@xmu.edu.cn

    2014-01-15

    Based on the experimental isothermal entropy change of the magnetic materials Gd{sub x}Dy{sub 1−x}, the thermodynamic performance of a regeneration Ericsson refrigeration cycle is evaluated and analyzed. The effects of non-perfect regeneration on the cyclic performance are highlighted. For a room temperature hot reservoir, the cooling quantity, non-perfect regeneration heat quantity, and net cooling quantity of the established regeneration Ericsson refrigeration cycle are calculated as a function of the cold reservoir temperature. Furthermore, for several typical compositions x of the Gd{sub x}Dy{sub 1−x} alloys, the values of the cooling quantity, non-perfect regeneration heat quantity, work input, net cooling quantity, and coefficient of performance (COP) are listed for given temperatures of the cold reservoir. The cyclic performance of the Gd{sub x}Dy{sub 1−x} alloys with different composition x is compared and some significant analyses are provided. - Highlights: • We examine the thermodynamics properties of the magnetocaloric alloys Gd{sub x}Dy{sub 1−x}. • We model a magnetic Ericsson cycle with regeneration process. • Calculations are based on experimental isothermal entropies change. • A cold reservoir temperature limit was found depending on ‘x’ composition value and operating conditions. • Lowest ‘x’ composition values have larger COP but lower net cooling quantities.

  6. Superconducting Dy1-x(Gd,Yb)xBa2Cu3O7-δ thin films made by Chemical Solution Deposition

    DEFF Research Database (Denmark)

    Opata, Yuri Aparecido; Wulff, Anders Christian; Hansen, Jørn Otto Bindslev

    2016-01-01

    Dy1-x(Gd or Yb)xBa2Cu3O7-δ samples were prepared using chemical solution deposition (CSD), based on trifluoroacetate metal-organic decomposition (MOD) methods. X-ray diffraction results demonstrated the formation of the RE123 superconducting phase with a strong in-plane and out-of-plane texture. c...

  7. Crystallization and magnetic characterizations of DyIG and HoIG nanopowders fabricated using citrate sol-gel

    Directory of Open Access Journals (Sweden)

    Dao Thi Thuy Nguyet

    2016-06-01

    Full Text Available Dy and Ho iron garnets in form of nanoparticles were synthesized by citrate sol-gel method. Phase formation, lattice constant and average crystallite sizes of the samples were determined via XRD measurements. Morphology and particle size distribution were studied by TEM and chemical composition was checked by EDX. Magnetic measurements in temperature range 5–600 K and in the maximum applied field of 50 kOe were carried out by using SQUID and VSM. Their magnetic parameters, including Curie temperature, magnetization compensation temperature, spontaneous magnetization, high-field susceptibility, magnetic coercivity were discussed in the framework of three interacting magnetic sublattices, magnetocrystalline anisotropy, core-shell model and compared to those of the bulk materials. Based on these analyses further evaluation on the crystallinity and homogeneity of the samples has been made.

  8. Effect of Li+ ion sensitization and optical temperature sensing in Gd2O3: Ho3+/Yb3+

    Science.gov (United States)

    Singh, Priyam; Shahi, P. K.; Rai, Anita; Bahadur, A.; Rai, S. B.

    2016-08-01

    Ho3+/Yb3+ codoped Gd2O3 phosphor has been synthesized by solution combustion method. The concentrations of Ho3+ and Yb3+ were optimized to be 0.3 and 2.0 mol% respectively for maximum emission intensity. The effect of Li+ ion co-doping on phase structure and photo luminescence were investigated. It is found that there is no change in phase of the sample due to Li+ ion co-doping. However the Upconversion (UC) and Downshifting (DS) emission show a remarkable enhancement in intensity. It is concluded that, this enhancement in the emission intensity is mainly due to the change in crystal field around the Ho3+ ion and reduction in quenching centers. The optimum doping concentration of Li+ ion was found to be 20 mol%. We have further explored the temperature sensing behavior using the FIR technique. The maximum sensitivity is found to be 0.0092 K-1 at 505 K.

  9. Clinical trial of {sup 165}Dy-HMA and {sup 166}Ho-CHICO in the treatment of Rheumatoid knee synovitis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. Y.; Yoo, D. H.; Bae, S. C.; Jun, J. B. [Hanyang University, Seoul (Korea, Republic of); Lim, S. M.; Hong, S. W.; Lee, S. Y.; Cheon, D. G.; Kim, S. J. [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1997-07-01

    The untreated, chronic synovial inflammation leads to pannus formation and eventual destruction of the articular cartilage. In cases where medical therapy was unsuccessful, surgical or radiation synovectomy is necessary especially in the knee joints. The advantages of radiation synovectomy over surgical synovectomy are (1) greater destruction of diseased synovium, (2) reduced potential for blood clots and infection, (3) no requirement for anesthesia, and (4) less costly and less time consuming. Recently KAERI developed Dy-165 HMA, which was characterized by the absence of iron and a higher concentration of dysprosium. And then more recently KAERI also developed {sup 166}Ho-CHICO, which was characterized by relatively longer half-life(26.8 hr), more biological due to organic nature of chitosan, more even spatial distribution due to colloidal solution and more absorbable to synovium than Dy-165 HMA. We studied to evaluate the efficacy and safety of radiation synovectomy with Dy-165 HMA and {sup 166}Ho-CHICO in chronic rheumatoid synovitis with knee. The present study indicates that the Dy-165 HMA and {sup 166}Ho-CHICO are an effective and safe agent for radiation synovectomy. But further large scaled long-term follow up study and controlled study with steroid only are required. 15 refs. (author)

  10. Competing γ-rigid and γ-stable vibrations in neutron-rich Gd and Dy isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Budaca, R.; Budaca, A.I. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania)

    2015-10-15

    An exactly separable version of the Bohr Hamiltonian which combines the γ-stable and γ-rigid axial vibration-rotation is used to describe the collective properties of few neutron-rich transitional nuclei. The coupling between the two types of collective motion is managed through a rigidity parameter which also influences the geometry of the shape phase space. While the γ-angular part of the problem associated to axially symmetric shapes is treated within the small angles approximation and the stiff γ oscillation hypothesis, the β vibration is described by means of a Davidson potential. The resulting model have three free parameters not counting the scale and was successfully applied for the description of the collective spectra for few heavier isotopes of Gd and Dy. In both cases a critical nucleus was identified through a discontinuous behavior in respect to the rigidity parameter and relevant experimental observables. (orig.)

  11. Nuclear quadrupole interaction studies of C15 RMn2 hydrides ( R=Y ,Gd,Tb,Dy)

    Science.gov (United States)

    Forker, M.; Bedi, S. C.; Euler, H.

    2008-09-01

    The nuclear electric quadrupole interaction (QI) of the probe nucleus I111n/C111d in the paramagnetic phase of the C15 rare earth (R) manganese hydrides (deuterides) RMn2H(D)x , with R=Y , Gd, Tb, and Dy, has been investigated by perturbed angular-correlation spectroscopy. The QI between the C111d quadrupole moment and the electric-field gradient (EFG) at the probe nucleus on the Mn site has been measured as a function of temperature in TbMn2H(D)x in the concentration range 0≤x≤4.3 and in RMn2H(D)x , R=Y ,Gd,Dy at the highest H content of xtilde 4.3 . The relative temperature dependence of the EFG in the parent compounds RMn2 is twice as strong as in isostructural RAl2 which can be related to differences in the Debye temperatures resulting from different radius ratios rR/rMn and rR/rAl [Joseph-Gschneidner postulate, Scr. Metall.2, 631 (1968)]. Hydrogenation of RMn2 increases the magnitude of the EFG by a factor of 2 between x=0 and x=4.3 but leaves the relative temperature dependence almost unchanged. Only at concentrations x>3.6 the temperature coefficient of the QI is significantly larger than in uncharged RMn2 . These results are compared with the much stronger concentration dependence and the anomalous temperature dependence of the QI of C111d in the C15 hydrides HfV2Hx . Evidence for an exceptionally high H mobility in TbMn2Hx is presented. The measurements provide information on structural changes and magnetic ordering temperatures at different H concentrations.

  12. Structural Transition and Enhanced Ferromagnetic Properties of La, Nd, Gd, and Dy-Doped BiFeO3 Ceramics

    Science.gov (United States)

    Kumar, Ashwini; Varshney, Dinesh

    2015-11-01

    The structural, electrical, and magnetic properties of rare-earth-doped Bi0.8 RE0.2FeO3 ceramics (rare-earth (RE) = La, Nd, Gd, and Dy) synthesized by solid-state reaction are reported and discussed. The x-ray diffraction (XRD) patterns of Bi0.8La0.2FeO3 and Bi0.8Nd0.2FeO3 were indexed to rhombohedral ( R3 c) and triclinic ( P1) structures, respectively. Rietveld refinement of the XRD pattern of Bi0.8Dy0.2FeO3 confirmed its biphasic nature ( Pnma + R3 c space groups) whereas for Bi0.8Gd0.2FeO3 the orthorhombic phase with Pna21 symmetry made a major contribution, with minor contributions from the orthorhombic ( Pnma) and rhombohedral ( R3 c) phases. Raman spectroscopy revealed changes in BiFeO3 mode positions, in addition to structural changes, on RE ion substitution. The effect of RE ion substitution on dielectric constant and loss tangent were studied at room temperature in a wide range of frequency, 50 Hz-1 MHz. Room temperature magnetization-magnetic field ( M- H) measurements indicated that magnetization increased with increasing structural distortion and with partial destruction of the spin cycloid as a result of doping of BiFeO3 ceramics with rare earth ions. These compounds, with improved remnant magnetization and coercive field, are suitable for use in spin-based electronic devices.

  13. Preparation of {sup 166} Dy/{sup 166} Ho-Macro aggregates as an In vivo generator system for the treatment of arthrophaties; Preparacion de {sup 166} Dy/{sup 166} Ho-Macro agregados como un sistema de generador In vivo para el tratamiento de artropatias

    Energy Technology Data Exchange (ETDEWEB)

    Aldama A, T.K

    2003-07-01

    The present work reports the obtention of macro aggregates of hydroxides of Dysprosium-166/Holmium-166 ({sup 166} Dy/{sup 166} Ho-MH), as a generator system in vivo to be used in the treatment of arthritis rheumatoid. The {sup 166} Dy was obtained by neutron irradiation of {sup 166} DyO{sub 3} (enriched to 98.45%) by 20 h in the TRIGA Mark III Reactor and 50 h of decay, to the oxide of {sup 166} Dy/{sup 166} Ho formed, it was added HCl 0.12 N to obtain a final volume of 3.5 ml of solution of {sup 166} Dy/{sup 166} Ho chloride. The solution of {sup 166D}yCl{sub 3} solution was obtained with an activity of 3.502 mCi (129 MBq), appropriate for the preparation of the radiopharmaceutical {sup 166} Dy/{sup 166} Ho-MH. The separation of the {sup 166} Dy from the {sup 166} Ho, was carried out by chromatography in an cation exchange column, gaining an appropriate separation, obtaining a {sup 166} Dy with a radionuclide purity greater than 90%. The {sup 166} Dy/{sup 166} Ho-MH were prepared by addition to the solution of {sup 166} DyCI{sub 3} NaOH 0.5 N low ultrasonic bath with later centrifugation, decanted and resuspension in saline solution, obtaining a radiopharmaceutical with a generator system {sup 166} Dy/ {sup 166} Ho with particles of size average of 3 {mu}m, in form of {sup 166} Dy / {sup 166} Ho-MH. Under these conditions, it was obtained a radiochemical yield greater than 99%. The microscopic analysis and of filtration showed that the formulation doesn't present particles smaller than to 1 {mu}m, neither greater to 50 {mu}m, which will allow, the quick phagocytosis for the synoviocytes of the synovial membrane, and by consequence, an homogeneous distribution of the radiation dose could exist. The sedimentation velocity for the formulated suspension is of 0.04 cm/min that it will allow the administration of homogeneous activities of the radiopharmaceutical, to the no deposit in the injection devices. The studies of stability in vitro indicate us that inside

  14. Effect of rare-earth (Er and Gd) substitution on the magnetic and multiferroic properties of DyFe0.5Cr0.5O3

    Science.gov (United States)

    Sharma, Mohit K.; Basu, Tathamay; Mukherjee, K.; Sampathkumaran, E. V.

    2016-10-01

    We report the results of our investigations on the influence of partial substitution of Er and Gd for Dy on the magnetic and magnetoelectric properties of DyFe0.5Cr0.5O3, which is known to be a multiferroic system. Magnetic susceptibility and heat capacity data, apart from confirming the occurrence of magnetic transitions at ~121 and 13 K in DyFe0.5Cr0.5O3, bring out that the lower transition temperature only is suppressed by rare-earth substitution. Multiferroic behavior is found to persist in Dy0.4Ln0.6Fe0.5Cr0.5O3 (Ln  =  Er and Gd). There is an evidence for magnetoelectric coupling in all these materials with qualitative differences in its behavior as the temperature is changed across these two transitions. Remnant electric polarization is observed for all the compounds. The most notable observation is that electric polarization is seen to get enhanced as a result of rare-earth substitution with respect to that in DyFe0.5Cr0.5O3. Interestingly, a similar trend is seen in the magnetocaloric effect, consistent with the existence of magnetoelectric coupling. The results thus provide evidence for the tuning of magnetoelectric coupling by rare-earth substitution in this family of oxides.

  15. Photoluminescence properties of novel Sm{sup 3+} and Dy{sup 3+} co-activated CsGd(WO{sub 4}){sub 2} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Balaji, D.; Kavirasu, K.; Durairajan, A.; Moorthy Babu, S., E-mail: babusm@yahoo.com

    2015-07-15

    Highlights: • Sm{sup 3+} and Dy{sup 3+} co-activated CsGd(WO{sub 4}){sub 2} phosphors were synthesized by sol–gel method. • Sm{sup 3+} and Dy{sup 3+} co-activated CsGd(WO{sub 4}){sub 2} phosphors were characterized by XRD, Raman, PL, SEM. • The photoluminescence process in the Sm{sup 3+} and Dy{sup 3+} co-activated CsGd(WO{sub 4}){sub 2} phosphors was described. • The emission lies in the greenish-yellow and warm white. • CIE color coordinates and CCT values were estimated. - Abstract: CsGd(WO{sub 4}){sub 2} (CGW) phosphors with different concentration of singly-doped Sm{sup 3+} or Dy{sup 3+} ions and co-doped Sm{sup 3+}/Dy{sup 3+} ions were prepared through polymeric sol–gel method. The phosphors were characterized by means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman and luminescence analysis. The excitation spectra of the phosphors reveal a broad charge transfer band in the short wavelength region and several sharp lines in the longer wavelength region which indicates that these phosphors can be effectively excited by UV and blue LED’s. The CGW: Dy{sup 3+}, Sm{sup 3+} phosphors exhibit the emission peaks in the blue ({sup 4}F{sub 9/2} → {sup 6}H{sub 15/2}), yellow ({sup 4}F{sub 9/2} → {sup 6}H{sub 13/2}) and orange–red ({sup 4}G{sub 5/2} → {sup 6}H{sub J=5/2,} {sub 7/2,} {sub 9/2}) regions under the excitation wavelength of 365 nm. The emission spectrum of the co-doped phosphors explains the spread of sensitizing effects from the Dy{sup 3+} ions to the Sm{sup 3+} ions. All the decay curves are well fitted by the bi-exponential functions. White color chromaticity coordinates (x = 0.33, y = 0.33) were achieved by optimizing the doping concentration of Sm{sup 3+} in Dy{sup 3+} doped CGW phosphors.

  16. Synthesis of Gd2O3:Ho3+/Yb3+ upconversion nanoparticles for latent fingermark detection on difficult surfaces

    Science.gov (United States)

    Kumar, A.; Tiwari, S. P.; Singh, A. K.; Kumar, K.

    2016-07-01

    Infrared to visible upconversion fluorescent nanoparticles of Gd2O3 codoped with Ho3+/Yb3+ ions are synthesized via thermal decomposition process. The X-ray diffraction analysis of as-synthesized nanoparticles and annealed sample at 1000 °C has shown body-centered cubic phase of Gd2O3. The synthesized phosphor has shown intense green emission upon 980-nm excitation. High-contrast latent fingermarks on some difficult semi-porous and non-porous surfaces under 980-nm diode laser excitation were developed through powder dusting and colloidal solution spraying techniques and the results are compared with the commercial green luminescent fingermark powder. The latent fingermarks were developed on transparent (biological glass slides), single-color (aluminum foil) and multicolor (plywood, plastic bottle and book cover page) background surfaces. The present study depicts that the upconversion-based latent fingermarks detection using Gd2O3:Ho3+/Yb3+ phosphor material is suitable over the other conventional powders and has potential for practical applications in forensic science.

  17. Synthesis and structural characterization of the stoichiometric elpasolites of Dy{sup 3+} and Ho{sup 3+}; Sintesis y caracterizacion estructural de las elpasolitas estequiometricas de Dy{sup 3+} y Ho{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo, R.; Soto B, A. [Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile, Beauchef 850, Casilla 2777, Santiago (Chile); Navarro, G. [Instituto de Ciencias Basicas, Facultad de Ingenieria, Universidad Diego Portales, Av. Ejercito 441, Casilla 298-V, Santiago (Chile); Martin, V. [Grupo de Materiales Nucleares, Comision Chilena de Energia Nuclear, La Reina, Casilla 188-D, Santiago (Chile)

    2005-07-01

    In this research paper, we report an updated set of experimental data, mainly structural in character, accurately determined for pure elpasolite systems such as Cs{sub 2}NaLnCI{sub 6}; M{sup 3+} = Dy{sup 3+}(f{sup 9}), Ho(f{sup 10}), where the trivalent lanthanide ions occupy sites of octahedral symmetries. There is a vast amount of experimental data from spectroscopic techniques for this type of systems both, pure and doped as well as several attempts leading to the identification and assignment of the various peaks for the associated spectra. The understanding of the experimental data, is central and most relevant, when the many complexities observed in both, the absorption and emission spectra are taken into account showing up the need for carrying out new experiments and developing more general physical models in the spectroscopy of solid state physics. These models should be able to accommodate both the long and short range interactions as well as to include, in an explicit form, the coupling between the internal and the external vibrations for these systems. A further reason to preclude more comprehensive theoretical studies in this area is the well known fact that, for these systems the experimental data available obtained from X-ray and spectroscopic studies is both scarce and incomplete. In the current research paper, we report updated experimental data, essentially structural in character, obtained in our laboratory utilizing X ray diffraction for powders and we also report a neutron diffraction pattern for the Cs{sub 2}NaHoCl{sub 6}. (Author) 37 refs., 4 tabs., 7 figs.

  18. Photoelectron spectra of the late rare-earth misfit layer compounds (LnS)(1+x)TS2 (Ln=Tb, Dy, Ho; T=Nb, Ta)

    NARCIS (Netherlands)

    Fang, CM; Wiegers, GA; Haas, C

    1997-01-01

    Photoemission spectra (XPS and UPS) are presented for the valence band of misfit layer compounds (LnS)(1+x)TS2 with Ln = Dy, Ho or Tb; T = Nb or Ta. The Nb 4d(x)2 (or Ta 5d(x)2) conduction band is almost filled, which indicates a charge transfer of slightly less than one electron per T from the LnS

  19. Full potential calculations and atom in molecule analysis of the bonding properties of perovskites Borides XRh3B (X=Dy, Ho, Er)

    OpenAIRE

    Ouahrani T.; Merad Boudia I.; Lasri B.

    2013-01-01

    ab initio calculations were performed for the cubic perovskites Borides XRh3B, (X=Dy, Ho, Er). In this work, we have used the augmented plane-wave plus local orbital method to compute the equilibrium structural parameters and electronic structure of densities of states, as well as for the first time, prediction of the thermo-elastic properties of these crystals are presented. The chemical bonding of these compounds has been investigated by using of topological analyses grounded in the theory ...

  20. Oxide fluoride sulfides of the lanthanoids with the formula M{sub 3}OF{sub 5}S (M = Nd, Sm, Gd-Ho); Oxidfluoridsulfide der Lanthanoide vom Formeltyp M{sub 3}OF{sub 5}S (M = Nd, Sm, Gd-Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Grossholz, Hagen; Janka, Oliver; Schleid, Thomas [Stuttgart Univ. (Germany). Inst. fuer Anorganische Chemie

    2011-03-15

    First attempts to synthesize a lanthanoid(III) oxide fluoride sulfide were successful by reacting DyF{sub 3} and Dy{sub 2}O{sub 3} with dysprosium and sulfur in a 2: 5: 1: 3 molar ratio at 850 C in tightly sealed tantalum ampoules. In analogy to the dysprosium compound Dy{sub 3}OF{sub 5}S, the other representatives of the M{sub 3}OF{sub 5}S series with M = Nd, Sm, Gd-Ho could be prepared as well. Almost phase-pure samples were obtained under similar flux-assisted (NaCl) conditions according to 2M + 5MF{sub 3} + M{sub 2}O{sub 3} + 3S {yields} 3M{sub 3}OF{sub 5}S. In the hexagonal crystal structure (space group: P6{sub 3}/m; a {approx} 961-939 pm, c {approx} 378-367 pm; c/a {approx} 0.39, V{sub m} {approx} 91-84 cm{sup 3}mol{sup -1}, Z = 2), the M{sup 3+} cations reside in ninefold anionic coordination realized as tricapped trigonal prisms formed by seven light (O{sup 2-}/F{sup -}) and two heavier S{sup 2-} anions. One light-anion position exhibits the exclusive character of F{sup -} in trigonal non-planar coordination (CN = 3), while the other position with a tetrahedral cationic environment (CN = 4) is mixed occupied by F{sup -} and O{sup 2-} in a 2: 1 ratio. The S{sup 2-} anions are coordinated in a trigonal prismatic way by six M{sup 3+} cations. From the data of single-crystal X-ray structure analyses, no indication of any ordering for the O{sup 2-} and F{sup -} anions could be obtained, but bond-valence and MAPLE calculations confirmed the results of electron-beam microanalyses carried out earlier to reveal ordered models for Dy{sub 3}OF{sub 5}S. (orig.)

  1. Crystal structure and Mössbauer studies of the isotypic Fe6-cluster compounds RE15[Fe8C25], RE=Dy, Ho

    KAUST Repository

    Davaasuren, Bambar

    2015-05-01

    The carboferrates RE15[Fe8C25] (RE=Dy, Ho) were prepared from mixtures of the elements by arc-melting followed with subsequent annealing at 1373 K. The crystal structures were determined from single crystal X-ray diffraction data and revealed an isotypic relationship to Er15[Fe8C25] (hP48, P321). The main feature of the crystal structure is given by Fe6 cluster units characterized by covalent Fe-Fe bonding interactions. 57Fe Mössbauer spectra of Dy15[Fe8C25] were fitted by three subspectra with relative spectral weights of about 3:3:2 which is in general agreement with the crystal structure. Below 50 K, an onset of magnetic hyperfine fields at the three iron sites is observed which is supposed to be caused by dipolar fields arising from neighboring, slowly relaxing Dy magnetic moments.

  2. Rhombus-shaped tetranuclear [Ln4] complexes [Ln = Dy(III) and Ho(III)]: synthesis, structure, and SMM behavior.

    Science.gov (United States)

    Chandrasekhar, Vadapalli; Hossain, Sakiat; Das, Sourav; Biswas, Sourav; Sutter, Jean-Pascal

    2013-06-03

    The reaction of a new hexadentate Schiff base hydrazide ligand (LH3) with rare earth(III) chloride salts in the presence of triethylamine as the base afforded two planar tetranuclear neutral complexes: [{(LH)2Dy4}(μ2-O)4](H2O)8·2CH3OH·8H2O (1) and [{(LH)2Ho4}(μ2-O)4](H2O)8·6CH3OH·4H2O (2). These neutral complexes possess a structure in which all of the lanthanide ions and the donor atoms of the ligand remain in a perfect plane. Each doubly deprotonated ligand holds two Ln(III) ions in its two distinct chelating coordination pockets to form [LH(Ln)2](4+) units. Two such units are connected by four [μ2-O](2-) ligands to form a planar tetranuclear assembly with an Ln(III)4 core that possesses a rhombus-shaped structure. Detailed static and dynamic magnetic analysis of 1 and 2 revealed single-molecule magnet (SMM) behavior for complex 1. A peculiar feature of the χM" versus temperature curve is that two peaks that are frequency-dependent are revealed, indicating the occurrence of two relaxation processes that lead to two energy barriers (16.8 and 54.2 K) and time constants (τ0 = 1.4 × 10(-6) s, τ0 = 7.2 × 10(-7) s). This was related to the presence of two distinct geometrical sites for Dy(III) in complex 1.

  3. 2-and 1-D coordination polymers of Dy(III) and Ho(III) with near infrared and visible luminescence by efficient charge-transfer antenna ligand

    Science.gov (United States)

    Oylumluoglu, Gorkem; Coban, Mustafa Burak; Kocak, Cagdas; Aygun, Muhittin; Kara, Hulya

    2017-10-01

    Two new lanthanide-based coordination complexes, [Dy(2-stp).2(H2O)]n (1) and {[Ho(2-stp).3(H2O)]·(H2O)}n (2) [2-stp = 2-sulfoterephthalic acid] were synthesized by hydrothermal reaction and characterized by elemental analysis, UV, IR, single crystal X-ray diffraction and solid state photoluminescence. DyIII and HoIII atoms are eight-coordinated and adopt a distorted square-antiprismatic geometry in complexes 1 and 2, respectively. In compound 1, Dy atoms are coordinated by four bridging 2-stp ligands forming two-dimensional (2D) layer, while Ho atoms by three bridging 2-stp ligands creating one dimensional (1D) double chains in 2. In addition, complexes 1 and 2 display in the solid state and at room temperature an intense yellow emission, respectively; this photoluminescence is achieved by an indirect process (antenna effect). The excellent luminescent performances make these complexes very good candidates for potential luminescence materials.

  4. An ultrasmall and metabolizable PEGylated NaGdF4:Dy nanoprobe for high-performance T1/T2-weighted MR and CT multimodal imaging

    Science.gov (United States)

    Jin, Xiaoying; Fang, Fang; Liu, Jianhua; Jiang, Chunhuan; Han, Xueli; Song, Zhongkai; Chen, Jinxing; Sun, Guoying; Lei, Hao; Lu, Lehui

    2015-09-01

    Lanthanide-based multimodal probes with high sensitivity, simple synthesis strategy, and good biocompatibility promise new applications for clinical diagnosis. However, today's challenge is not only to develop high-performance multimodal probes for more accurate and reliable diagnosis, but also to understand the fate of these probes in vivo. In this context, a novel PEGylated Dy-doped NaGdF4 nanoprobe (PEG-NaGdF4:Dy) was designed and fabricated as a T1/T2-weighted MRI/CT imaging agent. This nanoprobe has a distinct longitudinal relaxivity (r1 = 5.17 mM-1 s-1), relatively high transverse relaxivity (r2 = 10.64 mM-1 s-1), and exhibits strong X-ray attenuation properties (44.70 HU L g-1) in vitro. Furthermore, T1/T2-weighted MRI/CT imaging in vivo confirmed that this PEG-NaGdF4:Dy nanoprobe could lead to a significant contrast enhancement effect on liver, spleen and kidney at 24 h post injection. The MTT assay, histological analysis, and biodistribution investigation demonstrated that this multifunctional nanoprobe possessed relatively low cytotoxicity, negligible tissue damage and could be completely excreted out of the body of mice as time prolonged. Therefore, the present PEG-NaGdF4:Dy nanoprobe has the potential for the development of multifunctional T1/T2-weighted MRI/CT imaging to provide more comprehensive and accurate diagnosis information.Lanthanide-based multimodal probes with high sensitivity, simple synthesis strategy, and good biocompatibility promise new applications for clinical diagnosis. However, today's challenge is not only to develop high-performance multimodal probes for more accurate and reliable diagnosis, but also to understand the fate of these probes in vivo. In this context, a novel PEGylated Dy-doped NaGdF4 nanoprobe (PEG-NaGdF4:Dy) was designed and fabricated as a T1/T2-weighted MRI/CT imaging agent. This nanoprobe has a distinct longitudinal relaxivity (r1 = 5.17 mM-1 s-1), relatively high transverse relaxivity (r2 = 10.64 mM-1 s-1), and

  5. Magnetic Ground States of the Rare-Earth Tripod Kagome Lattice Mg2 RE3 Sb3 O14 (RE =Gd ,Dy ,Er )

    Science.gov (United States)

    Dun, Z. L.; Trinh, J.; Li, K.; Lee, M.; Chen, K. W.; Baumbach, R.; Hu, Y. F.; Wang, Y. X.; Choi, E. S.; Shastry, B. S.; Ramirez, A. P.; Zhou, H. D.

    2016-04-01

    We present the structural and magnetic properties of a new compound family, Mg2 RE3 Sb3 O14 (RE =Gd ,Dy ,Er ), with a hitherto unstudied frustrating lattice, the "tripod kagome" structure. Susceptibility (ac, dc) and specific heat exhibit features that are understood within a simple Luttinger-Tisza-type theory. For RE =Gd , we found long-ranged order (LRO) at 1.65 K, which is consistent with a 120° structure, demonstrating the importance of diople interactions for this 2D Heisenberg system. For RE =Dy , LRO at 0.37 K is related to the "kagome spin ice" physics for a 2D system. This result shows that the tripod kagome structure accelerates the transition to LRO predicted for the related pyrochlore systems. For RE =Er , two transitions, at 80 mK and 2.1 K are observed, suggesting the importance of quantum fluctuations for this putative X Y system.

  6. High - pressure synchrotron x-ray diffraction study of RMnO3 (R = Eu, Gd, Tb and Dy) upto 50 GPa

    Science.gov (United States)

    Muthu, D. V. S.; Midgley, A. E.; Scott, P. R.; Kruger, M. B.; Sahu, J. R.; Sood, A. K.; Rao, C. N. R.

    2012-07-01

    We have carried out synchrotron based high-pressure x-ray diffraction study of orthorhombic EuMnO3, GdMnO3, TbMnO3 and DyMnO3 up to 54.4, 41.6, 47.0 and 50.2 GPa, respectively. The diffraction peaks of all the four manganites shift monotonically to higher diffraction angles and the crystals retain the orthorhombic structure till the highest pressure. We have fitted the observed volume versus pressure data with the Birch-Murnaghan equation of state and determined the bulk modulus to be 185 ± 6 GPa, 190 ± 16 GPa, 188 ± 9 GPa and 192 ± 8 GPa for EuMnO3, GdMnO3, TbMnO3 and DyMnO3, respectively. The bulk modulus of EuMnO3 is comparable to other manganites, in contrast to theoretical predictions.

  7. A Single-Longitudinal-Mode Dual-Wavelength cw Tm,Ho: GdVO4 Microchip Laser

    Institute of Scientific and Technical Information of China (English)

    JU You-Lun; WANG Zhen-Guo; LI Yu-Feng; WANG Yue-Zhu

    2008-01-01

    A liquid nitrogen cooled dual-wavelength Tm,Ho:GdVO4 microchip laser is reported. The output dual wavelengths are at 2038.9nm and 2050.1nm. At each wavelength, the laser has a single longitudinal mode. The threshold power is nearly 20mW and the slope efficiency is 18.7%. The single longitudinal mode output power reaches 98mW, and the ratio of power is about 60% (2038.9nm) and 40% (2050.1 nm).

  8. Magnetic properties of NiFe{sub 2−x}RE{sub x}O{sub 4} (RE=Dy, Gd) using magnetic Compton scattering

    Energy Technology Data Exchange (ETDEWEB)

    Sahariya, Jagrati; Mund, H.S.; Sharma, Arvind [Department of Physics, M.L. Sukhadia University, Udaipur 313001 (India); Dashora, Alpa [Department of Physics, University of Mumbai, Vidyanagri, Santacruz (E), Mumbai 400098 (India); Itou, M.; Sakurai, Y. [Japan Synchrotron Radiation Research Institute, SPring8, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Ahuja, B.L., E-mail: blahuja@yahoo.com [Department of Physics, M.L. Sukhadia University, Udaipur 313001 (India)

    2014-06-01

    Temperature dependent spin momentum densities of NiFe{sub 2−x}RE{sub x}O{sub 4} (x=0, 0.05; RE=Dy, Gd) ferrites have been measured using a magnetic Compton spectrometer available at SPring-8, Japan. The experimental profiles of NiFe{sub 2}O{sub 4} (NFO) with doping of Dy and Gd show almost similar spin moment as of undoped NFO. The contribution of different constituents in the formation of total spin moment is also deduced from the analysis of Compton line shape. It is seen that 5% doping of Dy{sup 3+} or Gd{sup 3+} ions at Fe{sup 3+} sites leads to a redistribution of spin moment at Fe{sup 3+} and RE{sup 3+} sites. The magnetic Compton data when compared with the magnetization data (using a vibrating sample magnetometer) show almost a constant orbital moment (0.21±0.03 µ{sub B}/f.u.) in the doped and undoped NFO. - Highlights: • Reported first ever magnetic Compton profiles (MCPs) of NiFe{sub 2−x}RE{sub x}O{sub 4} (RE=Dy, Gd). • MCPs are analyzed to determine site specific contributions in total spin moment. • Doping of RE{sup 3+} ions at Fe{sup 3+} sites redistributes the spin moment at Fe{sup 3+} and RE{sup 3+} sites. • The orbital moments in doped and undoped ferrites are found to be almost constant.

  9. Hydrothermal Synthesis and Characterization of Pyrochlore Titanate R2 Ti2O7(R=Gd3+, Tb3+, Dy3+)

    Institute of Scientific and Technical Information of China (English)

    PENG Wen; HU Bin; CHEN Yan; HU Wei-wei; GUO Li; YUAN Hong-ming; FENG Shou-hua

    2011-01-01

    Pyrochlore titanate oxides, R2Ti2O7(R=Gd3+, Tb3+, Dy3+), were synthesized under mild hydrothermal conditions. The crystal growth of pyrochlore titanate oxides and taking place of chemical reaction in the hydrothermal processing were sensitive to the alkalinity, temperature, reaction time, the nature of the rare earth ion and the composition of initial reaction mixture. The as-prepared samples were characterized by powder X-ray diffraction, scanning electron microscopy, Raman spectrum and variable temperature dc magnetic susceptibility(Superconductivity quantum interference device, SQUIDS). The magnetic studies gave 7.29× 10-23 A·m2/Gd3+ and -8.28 K, 8.75 × 10-23 A·m2/ Tb3+ and -19.7 K, and 8.85×10-23 A·m2/Dy3+ and 0.84 K effective moments and Weiss constants for Gd2Ti2O7,Tb2Ti2O7 and Dy2Ti2O7, respectively.

  10. Structural refinement, band-gap analysis and optical properties of GdAlO3 nanophosphors influenced by Dy3+ ion concentrations for white light emitting device applications

    Science.gov (United States)

    Jisha, P. K.; Naik, Ramachandra; Prashantha, S. C.; Nagaswarupa, H. P.; Nagabhushana, H.; Basavaraj, R. B.; Sharma, S. C.; Prasad, Daruka

    2016-04-01

    Nanosized GdAlO3 phosphors activated with Dy3+ were prepared by a combustion method. Synthesized phosphors were calcined at 1000 °C for 3 h in order to achieve crystallinity. Powder x-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis was used to characterize the prepared product. The orthorhombic phase was observed in the XRD pattern. The particle size of the samples was calculated as around 25 nm. The SEM images show an irregular shape of the prepared nanophosphor. Functional groups of the phosphors were examined by Fourier transform infrared (FTIR) spectroscopy. Photoluminescence (PL) properties of Dy3+ doped GdAlO3 for near-ultraviolet excitation (352 nm) were studied in order to investigate the possibility of its use in white light emitting device applications. Judd-Ofelt intensity parameters, radiative transition rate (A T) and radiative lifetimes (τ rad) were evaluated from the emission spectrum by adopting a standard procedure. The Commission International de l’Eclairage (CIE) color coordinates and correlated color temperature (CCT) are studied for the optimized phosphor. It is found that the color coordinates of Dy3+ doped GdAlO3 powders fall in the white region of the CIE diagram, and the average CCT value was found to be about 6276 K. Therefore, the present phosphor is highly useful for display applications.

  11. Cubic Phases in the Gd2O3-ZrO2 and Dy2O3-TiO2 Systems for Nuclear Industry Applications

    Directory of Open Access Journals (Sweden)

    Maria Teresa Malachevsky

    2015-01-01

    Full Text Available Neutron absorbers are elements with a high neutron capture cross section that are employed at nuclear reactors to control excess fuel reactivity. If these absorbers are converted into materials of relatively low absorption cross section as the result of neutron absorption, they consume during the reactor core life and so are called burnable. These elements can be distributed inside an oxide ceramic that is stable under irradiation and thus called inert. Cubic zirconium oxide is one of the preferred materials to be used as inert matrix. It is stable under irradiation, experiments very low swelling, and is isomorphic to uranium oxide. The cubic phase is stabilized by adding small amounts of dopants like Dy2O3 and Gd2O3. As both dysprosium and gadolinium have a high neutron cross section, they are good candidates to prepare burnable neutron absorbers. Pyrochlores, like Gd2Zr2O7 and Dy2Ti2O7, allow the solid solution of a large quantity of elements besides being stable under irradiation. These characteristics make them also useful for safe storage of nuclear wastes. We present a preliminary study of the thermal analysis of different compositions in the systems Gd2O3-ZrO2 and Dy2O3-TiO2, investigating the feasibility to obtain oxide ceramics useful for the nuclear industry.

  12. Optical spectroscopy of Dy3+-doped CaGdAlO4 single crystal for potential use in solid-state yellow lasers

    Science.gov (United States)

    Xu, Xiaodong; Hu, Zongwen; Li, Ruijuan; Li, Dongzhen; Di, Juqing; Su, Liangbi; Yang, Qiuhong; Sai, Qinglin; Tang, Huili; Wang, Qingguo; Strzęp, Adam; Xu, Jun

    2017-04-01

    The crystal growth, optical spectra and lifetime of Dy:CaGdAlO4 crystal were investigated for the first time to our best knowledge. Single Dy:CaGdAlO4 crystal with size of Φ4 × 40 mm3 was grown by floating zone method. The peak absorption cross-sections were calculated to be 2.43 × 10-21cm2 and 1.28 × 10-21 cm2 at 453 nm for σ and π polarizations. The Judd-Ofelt (JO) parameters of Ω2, Ω4 and Ω6 were calculated to be 1.8 × 10-20cm2, 1.0 × 10-20cm2 and 0.5 × 10-20cm2, respectively. The emission cross-sections were calculated to be 0.51 × 10-20cm2 and 0.55 × 10-20cm2 for σ and π polarizations. The fluorescence decay time is 222 μs. The results indicate that the Dy:CaGdAlO4 crystal is a potential candidate for yellow laser operation.

  13. Pressure-induced enhancement of ferroelectricity in multiferroic RMn2O5 (R=Tb,Dy,Ho)

    Science.gov (United States)

    Dela Cruz, C. R.; Lorenz, B.; Sun, Y. Y.; Wang, Y.; Park, S.; Cheong, S.-W.; Gospodinov, M. M.; Chu, C. W.

    2007-11-01

    Measurements of ferroelectric polarization and dielectric constant were done on RMn2O5 (R=Tb,Dy,Ho) with applied hydrostatic pressures of up to 18kbar . At ambient pressure, distinctive anomalies were observed in the temperature profile of both physical properties at critical temperatures marking the onset of long range antiferromegnetic order (TN1) and ferroelectricity (TC1) , as well as at temperatures when anomalous changes in the polarization, dielectric constant, and spin wave commensurability have been previously reported. In particular, the step in the dielectric constant at low temperatures (TC2) , associated with both a drop in the ferroelectric polarization and an incommensurate magnetic structure, was shown to be suddenly quenched upon passing an R -dependent critical pressure. This was shown to correlate with the stabilization of the high ferroelectric polarization state, which is coincident with the commensurate magnetic structure. The observation is suggested to be due to a pressure-induced phase transition into a commensurate magnetic structure, as exemplified by the pressure-temperature (p-T) phase diagrams constructed in this work. The p-T phase diagrams are determined for all three compounds.

  14. Intermediate magnetization state and competing orders in Dy2Ti2O7 and Ho2Ti2O7

    Science.gov (United States)

    Borzi, R. A.; Gómez Albarracín, F. A.; Rosales, H. D.; Rossini, G. L.; Steppke, A.; Prabhakaran, D.; MacKenzie, A. P.; Cabra, D. C.; Grigera, S. A.

    2016-08-01

    Among the frustrated magnetic materials, spin-ice stands out as a particularly interesting system. Residual entropy, freezing and glassiness, Kasteleyn transitions and fractionalization of excitations in three dimensions all stem from a simple classical Hamiltonian. But is the usual spin-ice Hamiltonian a correct description of the experimental systems? Here we address this issue by measuring magnetic susceptibility in the two most studied spin-ice compounds, Dy2Ti2O7 and Ho2Ti2O7, using a vector magnet. Using these results, and guided by a theoretical analysis of possible distortions to the pyrochlore lattice, we construct an effective Hamiltonian and explore it using Monte Carlo simulations. We show how this Hamiltonian reproduces the experimental results, including the formation of a phase of intermediate polarization, and gives important information about the possible ground state of real spin-ice systems. Our work suggests an unusual situation in which distortions might contribute to the preservation rather than relief of the effects of frustration.

  15. Visible and near-IR spectroscopy of endohedral Gd@C82( C 2 v ) and Ho@C82( C 2 v ) metallofullerenes and their monoanions

    Science.gov (United States)

    Kareev, I. E.; Nekrasov, V. M.; Dutlov, A. E.; Martynenko, V. M.; Bubnov, V. P.; Laukhina, E.; Veciana, J.; Rovira, C.

    2017-03-01

    Solutions of endohedral Gd@C82( C 2 v ) and Ho@C82( C 2 v ) metallofullerenes are studied by means of visible and near-IR spectroscopy upon their conversion from neutral to the anionic form via a redox reaction with the electron donor potassium perchlorotriphenylmethide K(18-crown-6)[C(C6Cl5)3]. The concentrations of the studied solutions of endohedral Gd@C82( C 2 v ) and Ho@C82( C 2 v ) metallofullerenes in o-dichlorobenzene were determined from the spectroscopic data, and their molar extinction coefficients are calculated.

  16. Raman spectroscopy of rare-earth orthoferrites R FeO3 (R =La, Sm, Eu, Gd, Tb, Dy)

    Science.gov (United States)

    Weber, Mads Christof; Guennou, Mael; Zhao, Hong Jian; Íñiguez, Jorge; Vilarinho, Rui; Almeida, Abílio; Moreira, Joaquim Agostinho; Kreisel, Jens

    2016-12-01

    We report a Raman scattering study of six rare-earth orthoferrites R FeO3, with R = La, Sm, Eu, Gd, Tb, Dy. The use of extensive polarized Raman scattering of SmFeO3 and first-principles calculations enable the assignment of the observed phonon modes to vibrational symmetries and atomic displacements. The assignment of the spectra and their comparison throughout the whole series allow correlating the phonon modes with the orthorhombic structural distortions of R FeO3 perovskites. In particular, the positions of two specific A g modes scale linearly with the two FeO6 octahedra tilt angles, allowing the distortion to be tracked throughout the series. At variance with literature, we find that the two octahedra tilt angles scale differently with the vibration frequencies of their respective A g modes. This behavior, as well as the general relations between the tilt angles, the frequencies of the associated modes, and the ionic radii are rationalized in a simple Landau model. The reported Raman spectra and associated phonon-mode assignment provide reference data for structural investigations of the whole series of orthoferrites.

  17. Optical and magneto-optical properties of single crystals of RFe{sub 2} (R = Gd, Tb, Ho, and Lu) and GdCo{sub 2} intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.J.

    1999-02-12

    The author has studied the diagonal and off-diagonal optical conductivity of RFe{sub 2}(R = Gd, Tb, Ho, Lu) and GdCo{sub 2} single crystals grown by the flux method. Using spectroscopic ellipsometry the author has measured the dielectric function from 1.5 to 5.5 eV. The magneto-optical Kerr spectrometer at temperatures between 7 and 295 K and applied magnetic fields between 0.5 to 1.6 T. The apparatus and calibration method are described in detail. Using magneto-optical data and optical constants he derives the experimental value of the off-diagonal conductivity components. Theoretical calculations of optical conductivities and magneto-optical parameters were performed using the tight binding-linear muffin tin orbitals method within the local spin density approximation. He applied this TB-LMTO method to LuFe{sub 2}. The theoretical results obtained agree well with the experimental data. The oxidation effects on the diagonal part of the optical conductivity were considered using a three-phase model. The oxidation effects on the magneto-optical parameters were also considered by treating the oxide layer as a nonmagnetic thin transparent layer. These corrections change not only the magnitude but also the shape of the optical conductivity and the magneto-optical parameters.

  18. Crystal chemistry of the orthorhombic Ln2TiO5 compounds with Ln=La, Pr, Nd, Sm, Gd, Tb and Dy

    Science.gov (United States)

    Aughterson, Robert D.; Lumpkin, Gregory R.; Thorogood, Gordon J.; Zhang, Zhaoming; Gault, Baptiste; Cairney, Julie M.

    2015-07-01

    The crystal structures of seven samples of orthorhombic (Pnma) Ln2TiO5 compounds with Ln=La, Pr, Nd, Sm, Gd, Tb and Dy were refined by Rietveld analysis of synchrotron X-ray powder diffraction (S-XRD) data. With increasing size of the lanthanide cation, the lattice parameters increase systematically: c by only ~1.5% whereas both a and b by ~6% from Dy2TiO5 to La2TiO5. The mean Ti-O bond length only increases by ~1% with increasing radius of the Ln cation from Gd to La, primarily due to expansion of the pair of Ti-O3 bonds to opposite corners of the Ti-O5 square based pyramid polyhedra. For Dy2TiO5 and Tb2TiO5, a significant variation in Ti-O1 and Ti-O4 bond lengths results in an increased deformation of the Ti-O5 base. The particular configuration consists of large rhombic shaped tunnels and smaller triangular tunnels along the b axis, which have implications for defect formation and migration caused by radiation damage or the ionic conductivity.

  19. Synthesis and luminescent properties of polycrystalline Gd_2(MoO_4)_3:Dy~(3+) for white light-emitting diodes

    Institute of Scientific and Technical Information of China (English)

    XUE Yanna; XIAO Fen; ZHANG Qinyuan; JIANG Zhonghong

    2009-01-01

    Polycrystalline Gd_2(MoO_4)_3:Dy~(3+) phosphors have been synthesized by high temperature solid-state reaction method. The phos-phors were characterized with X-ray diffractometer, thermogravimetric analysis and different scanning calorimeter, scanning electron mi-croscopy, and photoluminescence spectrofluorimeter. Several peaks at 351,389, 425, 452, and 472 nm appeared in photoluminescence exci-tation spectrum, which matched well with the emission of the ultraviolet (UV) and blue-light emitting diode (LED) chips. Upon excitation at 389 nm UV light, intense emissions centered at 484, 575 and 668 nm were attributed to the transitions of ~4F_(9/2)→~6H_(15/2), ~4F_(9/2)→~6H_(13/2) and ~4F_(9/2)→~6H_(11/2) of Dy~(3+), respectively. The chromaticity coordinates and correlative color temperatures have been calculated and presented in the Commission International de I'Eclairage (CIE) diagrams. The results indicated that Gd_(1.9)(MoO_4)_3:Dy_(0.1)~(3+) with CIE coordinates of (x=0.38,y=0.41 ) and the correlative color temperature of 4134 K is a potential candidate for white LEDs.

  20. Atomic distribution, local structure and cation size effect in o-R1-xCaxMnO3 (R = Dy, Y, and Ho).

    Science.gov (United States)

    Jiang, Ning; Zhang, X; Yu, Yi

    2013-11-27

    We propose new interatomic potentials for the small rare-earth-based orthorhombic RMnO3 (R = Dy, Y, Ho), which accurately model the structural properties of these extreme cases of lanthanide manganate series. They are further employed to investigate the intrinsic defects in o-RMnO3 and the cation distribution and local structure in o-R1-xCaxMnO3 (R = Dy, Y, Ho). Schottky disorders are found to be the dominant structural defects, and the possibility of a small degree of anti-site disorder of R and Mn ions over A and B sites is found. The introduced Ca dopants tend to form chemically and structurally like CaMnO3 clusters in the lightly doped system, which can be regarded as representations of microscopic phase separation. The local structural disorder is reduced with increasing doping density. For o-R0.5Ca0.5MnO3 (R = Dy, Y, Ho), the charge ordering state is intrinsically favored, and the layer stripe model is shown to be energetically more favorable and structurally more reasonable. Moreover, the tendency to form charge ordered stripes increases with the decrease of R size. The local structure in the layer stripe pattern deviates largely from the average structure: RMnO3-like and CaMnO3-like layers are formed. The size of R ion has a significant influence on the doping effect on Jahn-Teller (JT) distortion and a manganate with a larger R will experience a larger reduction on the anisotropy of Mn-O bonds in Mn(3+)O6 octahedra. However, the change of octahedral tilting upon doping does not vary much with R radii.

  1. Crystal growth, transport, and the structural and magnetic properties of Ln(4)FeGa(12) with Ln = Y, Tb, Dy, Ho, and Er.

    Science.gov (United States)

    Drake, Brenton L; Grandjean, Fernande; Kangas, Michael J; Okudzeto, Edem K; Karki, Amar B; Sougrati, Moulay T; Young, David P; Long, Gary J; Chan, Julia Y

    2010-01-18

    Ln(4)FeGa(12), where Ln is Y, Tb, Dy, Ho, and Er, prepared by flux growth, crystallize with the cubic Y(4)PdGa(12) structure with the Im3m space group and with a = 8.5650(4), 8.5610(4), 8.5350(3), 8.5080(3), and 8.4760(3) A, respectively. The crystal structure consists of an iron-gallium octahedra and face-sharing rare-earth cuboctahedra of the Au(3)Cu type. Er(4)Fe(0.67)Ga(12) is iron-deficient, leading to a distortion of the octahedral and cuboctahedral environments due to the splitting of the Ga2 site into Ga2 and Ga3 sites. Further, interstitial octahedral sites that are unoccupied in Ln(4)FeGa(12) (Ln = Y, Tb, Dy, and Ho) are partially occupied by Fe2. Y(4)FeGa(12) exhibits weak itinerant ferromagnetism below 36 K. In contrast, Tb(4)FeGa(12), Dy(4)FeGa(12), Ho(4)FeGa(12), and Er(4)Fe(0.67)Ga(12) order antiferromagnetically with maxima in the molar magnetic susceptibilities at 26, 18.5, 9, and 6 K. All of the compounds exhibit metallic electric resistivity, and their iron-57 Mossbauer spectra, obtained between 4.2 and 295 K, exhibit a single-line absorption with a 4.2 K isomer shift of ca. 0.50 mm/s, a shift that is characteristic of iron in an iron-gallium intermetallic compound. A small but significant broadening in the spectral absorption line width is observed for Y(4)FeGa(12) below 40 K and results from the small hyperfine field arising from its spin-polarized itinerant electrons.

  2. Electronic and optical properties of rare earth trifluorides RF{sub 3} (R La, Ce, Pr, Nd, Gd and Dy)

    Energy Technology Data Exchange (ETDEWEB)

    Saini, Sapan Mohan [National Institute of Technology Raipur (C.G.) (India); Nautiyal, Tashi, E-mail: tashifph@iitr.ernet.in [Indian Institute of Technology Roorkee, Roorkee (U.K.) (India); Auluck, Sushil [Indian Institute of Technology Roorkee, Roorkee (U.K.) (India)

    2011-09-15

    Highlights: {yields} The electronic structure and optical properties of some rare earth trifluorides. {yields} Band structure and optical properties indicate these are large band gap insulators. {yields} The 4f electrons do not play a decisive role in the optical properties of these. - Abstract: This work presents the electronic structure and optical properties of some rare earth trifluorides (RF{sub 3}) coarsely covering a large range of rare-earths with R La, Ce, Pr, Nd, Gd and Dy. Our theoretical investigations are based on the first principles, using the full potential linearized augmented plane wave method with the inclusion of spin orbit coupling. The local spin density approximation (LSDA) and the Coulomb-corrected LSDA + U method have been employed. We find that the standard LSDA approach is incapable of correctly describing the electronic properties of such materials since it positions the f-bands incorrectly resulting in an incorrect metallic ground state. On the other hand, LSDA + U approximation, known for treating the highly correlated 4f electrons properly, is able to reproduce the correct insulating ground state. Interestingly, however, we do not find any significant differences in the optical properties calculated using LSDA and LSDA + U suggesting that the 4f electrons do not play a decisive role in the optical properties of these compounds. The reflectivity for all the compounds stays low till {approx}7 eV which is consistent with their large energy gaps. The calculated energy gaps are in good agreement with experiments. Our calculated reflectivity compares well with the experimental data and the results are analyzed in the light of band to band transitions.

  3. Direct Measurement of the Mass Difference of Ho163 and Dy163 Solves the Q-Value Puzzle for the Neutrino Mass Determination

    CERN Document Server

    Eliseev, S; Block, M; Chenmarev, S; Dorrer, H; Duellmann, Ch E; Enss, C; Filianin, P E; Gastaldo, L; Goncharov, M; Koester, U; Lautenschlaeger, F; Novikov, Yu N; Rischka, A; Schuessler, R X; Schweikhard, L; Tuerler, A

    2016-01-01

    The atomic mass difference of 163Ho and 163Dy has been directly measured with the Penning trap mass spectrometer SHIPTRAP applying the novel phase imaging ion cyclotron resonance technique. Our measurement has solved the long standing problem of large discrepancies in the Q value of the electron capture in 163Ho determined by different techniques. Our measured mass difference shifts the current Q value of 2555(16) eV evaluated in the Atomic Mass Evaluation 2012 [G. Audi et al., Chin. Phys. C 36, 1157 (2012)] by more than 7 sigma to 2833(30stat)(15sys) eV/c2. With the new mass difference it will be possible, e.g., to reach in the first phase of the ECHo experiment a statistical sensitivity to the neutrino mass below 10 eV, which will reduce its present upper limit by more than an order of magnitude.

  4. Effect of rapid quenching on the magnetism and magnetocaloric effect of equiatomic rare earth intermetallic compounds RNi (R = Gd, Tb and Ho)

    Science.gov (United States)

    Rajivgandhi, R.; Arout Chelvane, J.; Quezado, S.; Malik, S. K.; Nirmala, R.

    2017-07-01

    Magnetocaloric effect (MCE) in RNi (where R = Gd, Tb and Ho) compounds has been studied in their arc-melted and melt-spun forms. The compound GdNi has the orthorhombic CrB-type structure (Space group Cmcm, No. 63) and the compound HoNi has the orthorhombic FeB-type structure (Space group Pnma, No. 62) at room temperature regardless of their synthesis condition. However, arc-melted TbNi orders in a monoclinic structure (Space group P21/m, No. 11) and when it is rapidly quenched to a melt-spun form, it crystallizes in an orthorhombic structure (Space group Pnma, No. 62). The arc-melted GdNi, TbNi and HoNi compounds order ferromagnetically at ∼69 K, ∼67 K and ∼36 K (TC) respectively. While the melt-spun GdNi shows about 6 K increase in TC, the ordering temperature of TbNi remains nearly the same in both arc-melted and melt-spun forms. In contrast, a reduction in TC by about 8 K is observed in melt-spun HoNi, when compared to its arc-melted counterpart. Isothermal magnetic entropy change, ∆Sm, calculated from the field dependent magnetization data indicates an enhanced relative cooling power (RCP) for melt-spun GdNi for field changes of 20 kOe and 50 kOe. A lowered RCP value is observed in melt-spun TbNi and HoNi. These changes could have resulted from the competing shape anisotropy and the granular microstructure induced by the melt-spinning process. Tailoring the MCE of rare earth intermetallic compounds by suitably controlled synthesis techniques is certainly one of the directions to go forward in the search of giant magnetocaloric materials.

  5. Synthesis, structure, and magnetism of a family of heterometallic {Cu2Ln7} and {Cu4Ln12} (Ln = Gd, Tb, and Dy) complexes: the Gd analogues exhibiting a large magnetocaloric effect.

    Science.gov (United States)

    Langley, Stuart K; Moubaraki, Boujemaa; Tomasi, Corrado; Evangelisti, Marco; Brechin, Euan K; Murray, Keith S

    2014-12-15

    The syntheses, structures, and magnetic properties of two heterometallic Cu(II)-Ln(III) (Ln(III) = Gd, Tb, and Dy) families, utilizing triethanolamine and carboxylate ligands, are reported. The first structural motif displays a nonanuclear {Cu(II)2Ln(III)7} metallic core, while the second reveals a hexadecanuclear {Cu(II)4Ln(III)12} core. The differing nuclearities of the two families stem from the choice of carboxylic acid used in the synthesis. Magnetic studies show that the most impressive features are displayed by the {Cu(II)2Gd(III)7} and {Cu(II)4Gd(III)12} complexes, which display a large magnetocaloric effect, with entropy changes -ΔSm = 34.6 and 33.0 J kg(-1) K(-1) at T = 2.7 and 2.9 K, respectively, for a 9 T applied field change. It is also found that the {Cu(II)4Dy(III)12} complex displays single-molecule magnet behavior, with an anisotropy barrier to magnetization reversal of 10.1 K.

  6. Influence of Tuned Linker Functionality on Modulation of Magnetic Properties and Relaxation Dynamics in a Family of Six Isotypic Ln2 (Ln = Dy and Gd) Complexes.

    Science.gov (United States)

    Mukherjee, Soumya; Lu, Jingjing; Velmurugan, Gunasekaran; Singh, Shweta; Rajaraman, Gopalan; Tang, Jinkui; Ghosh, Sujit K

    2016-11-07

    A coordination complex family comprising of six new dinuclear symmetric lanthanide complexes, namely, [Ln2(Lx)2(L')2(CH3OH)2]·yG (H2Lx: three related yet distinct Schiff-base linkers; x = 1-3, according to the nomenclature of the Schiff-base linker employed herein. HL': 2,6-dimethoxyphenol. yG refers to crystallographically assigned guest solvent species in the respective complexes; y = number of solvent molecules; Ln(III) = Dy/Gd) were isolated employing a mixed-ligand strategy stemming out of a strategic variation of the functionalities introduced among the constituent Schiff-base linkers. The purposeful introduction of three diverse auxiliary groups with delicate differences in their electrostatic natures affects the local anisotropy and magnetic coupling of Ln(III) ion-environment in the ensuing Ln2 dinuclear complexes, consequentially resulting into distinctly dynamical magnetic behaviors among the investigated new-fangled family of isotypic Ln2 complexes. Among the entire family, subtle alterations in the chemical moieties render two of the Dy2 analogues to behave as single molecule magnets, while the other Dy2 congener merely exhibits slow relaxation of the magnetization. The current observation marks one of the rare paradigms, wherein magnetic behavior modulation was achieved by virtue of the omnipresent influence of subtly tuned linker functionalities among the constituent motifs of the lanthanide nanomagnets. To rationalize the observed difference in the magnetic coupling, density functional theory and ab initio calculations (CASSCF/RASSI-SO/POLY_ANISO) were performed on all six complexes. Subtle difference in the bond angles leads to difference in the J values observed for Gd2 complexes, while difference in the tunnel splitting associated with the structural alterations lead to variation in the magnetization blockade in the Dy2 complexes.

  7. Investigation of local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds using perturbed angular correlation gamma-gamma spectroscopy; Investigacao do magnetismo local em compostos intermetalicos do tipo RZn (R = Ce, Gd, Tb, Dy) e GdCu pela espectroscopia de correlacao angular gama-gama perturbada

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Brianna Bosch dos

    2010-07-01

    This work presents, from a microscopic point of view, a systematic study of the local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds through measurements of hyperfine interactions using the Perturbed Angular Correlation Gamma- Gamma Spectroscopy technique with {sup 111}In {yields} {sup 111}Cd and {sup 140}La {yields} {sup 140}Ce as probe nuclei. As the magnetism in these compounds originates from the 4f electrons of the rare-earth elements it is interesting to observe in a systematic study of RZn compounds the behavior of the magnetic hyperfine field with the variation of the number of 4f electrons in the R element. The use of probe nuclei {sup 140}La {yields} {sup 140}Ce is interesting because Ce{sup +3} ion posses one 4f electron which may contribute to the total hyperfine field, and the results showed anomalous behavior. The results for {sup 111}Cd probe showed that the temperature dependence of the magnetic hyperfine field follows the Brillouin function, and the magnetic hyperfine field decreases linearly with increase of the atomic number of rare earth when plotted as a function of the rare-earth J spin projection, showing that the main contribution to the magnetic hyperfine field in RZn compounds comes from the polarization of the conduction electrons. The results for the electric field gradient measured with {sup 111}Cd for all compounds showed a strong decrease with the atomic number of the rare-earth element. We have therefore assumed that the major contribution to the electric field gradient originates from the 4f electrons of the rare-earths. The measurements of the electric field gradient for GdCu with {sup 111}Cd, after temperature decreases and increases again showed that two different structures, CsCl-type cubic and FeB-type orthorhombic structures co-exist. Finally, it is the first time that measurements of hyperfine parameters have been carried out with theses two probe nuclei in the studied RZn. (author)

  8. Magnetocaloric properties of TbN, DyN and HoN nanopowders prepared by the plasma arc discharge method.

    Science.gov (United States)

    Shinde, K P; Jang, S H; Kim, J W; Kim, D S; Ranot, M; Chung, K C

    2015-12-21

    We report for the first time the synthesis of nanopowders of TbN, DyN and HoN crystallized in a cubic structure by the plasma arc discharge (PAD) method and investigate their magnetocaloric properties for magnetic refrigeration applications. The nitridization of terbium, dysprosium and holmium was obtained using a mixture of nitrogen and argon gas inside a discharge chamber with 4 kPa pressure. The structural and microstructural properties of these rare earth nitrides were investigated by using X-ray diffraction and transmission electron microscopy. The studied nitrides undergo a second-order ferromagnetic to paramagnetic phase transition at Curie temperatures of 35.7, 19.9 and 14.2 K for TbN, DyN and HoN, respectively. The magnetocaloric effects were estimated by calculating the magnetic entropy changes from the magnetization data sets measured at the different applied magnetic fields and temperatures. The changes in entropy -ΔSM were found to be 12.0, 13.6 and 24.5 J kg(-1) K(-1) at an applied magnetic field of 5 T.

  9. Enhanced Magnetostriction of a Narrow Hysteresis Tb0.26Dy0.54Ho0.20Fe2 Alloy

    Institute of Scientific and Technical Information of China (English)

    Xingwen PAN; Changsheng ZHANG; Tianyu MA; Mi YAN; Jing LI

    2013-01-01

    In this work,a magnetic annealing method used to enhance the magnetostrictive property of a narrow hysteresis alloy Tb0.26Dy0.54Ho0.20Fe2 is reported.Cylindrical-rod shaped specimen with crystal orientation was fabricated using zone-melting unidirectional solidification technique,followed by annealing in a transverse magnetic field of 366 kA/m.The crystal orientation and bi-phase solidified morphology can be retained after magnetic annealing.A high magnetostriction of 1.508×10-3 was obtained in the magnetically annealed specimen,which is 25.2% larger than the untreated one.Simultaneously,the magnetostriction hysteresis width is slightly enlarged from 4.45 to 6.36 kA/m,which is still much lower than that of the Ho-free Tb0.3Dy0.7Fe2 alloy.The additional anisotropy which is induced by magnetic annealing,as reflected by the magnetic hysteresis loops,is responsible for the enhancement of magnetostrictive performance.

  10. Single-particle and collective mode couplings associated with 1- and 2-directional electronic ordering in metallic RTe3 (R=Ho,Dy,Tb).

    Science.gov (United States)

    Yusupov, R V; Mertelj, T; Chu, J-H; Fisher, I R; Mihailovic, D

    2008-12-12

    The coupling of phonons with collective modes and single-particle gap excitations associated with one- (1d) and two-directional (2d) electronically driven charge-density wave (CDW) ordering in metallic RTe3 is investigated as a function of rare-earth ion chemical pressure (R=Tb,Dy,Ho) using femtosecond pump-probe spectroscopy. From the T dependence of the CDW gap DeltaCDW and the amplitude mode, we find that while the transition to a 1d-CDW ordered state at Tc1 initially proceeds in an exemplary mean-field-like fashion, below Tc1, DeltaCDW is depressed and departs from the mean-field behavior. The effect is apparently triggered by resonant mode mixing of the amplitude mode with a totally symmetric phonon at 1.75 THz. At low temperatures, when the state evolves into a 2d-CDW ordered state at Tc2 in the DyTe3 and HoTe3, additional much weaker mode mixing is evident but no soft mode is observed.

  11. Stability constants of La(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III) and Dy(III) complexes with N-(2-hydroxyphenyl) p-toluene sulphonamide

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, S.C.; Mathur, K.C. (Jodhpur Univ. (India). Dept. of Chemistry)

    1981-01-01

    The dissociation constants of the ligand and stability constants of La(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III) and Dy(III) complexes with N-(2-hydroxyphenyl) p-toluene sulphonamide have been determined potentiometrically using Calvin-Bjerrum pH titration technique at 30 +- 1deg C and ..mu.. = 0.1 M (NaClO/sub 4/) in aqueous medium. The stability constants of these metal complexes are found to follow the order Dy > Tb > Gd > Sm > Nd > Pr > La.

  12. Photoluminescent properties of Ca2Gd8(SiO4)6O2: Dy3+ phosphor films prepared by sol-gel process

    Institute of Scientific and Technical Information of China (English)

    HAN Xiumei; LIN Jun; LI Zhe; QI Xiwei; LI Mingya; WANG Xiaoqiang

    2008-01-01

    There are growing interests on phosphor thin films owing to their potential application in high-resolution devices such as cathode ray tubes and fiat panel display devices. The solution-based sol-gel method is one of the most important techniques for the synthesis of vari-ous functional coating films. Compounds with the apatite structure are very suitable host lattices for various luminescent ions. Ca2RE8(SiO4)6O2 (RE=Y, Gd, La) is a kind of ternary rare-earth-metal silicate with oxyapatite structure, which has been used as host mate-rial for the luminescence of various rare earth and mercury-like ions. In this article, Ca2Gd8(SiO4)6O2:Dy3+phosphor films were dip-coated on quartz glass substrates through the sol-gel process. X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) spectra, as well as lifetimes were used to characterize the resulting films. AFM study revealed that the phosphor films consisted of homoge-neous particles. The Dy3+ showed its characteristic emission in crystalline phosphor films, i.e., 4F9/2-6H15/2 and 4F9/2-613/2.

  13. Triple-layered perovskite niobates CaRNb3O10 (R = La, Sm, Eu, Gd, Dy, Er, Yb, or Y): new self-activated oxides.

    Science.gov (United States)

    Qin, Lin; Wei, Donglei; Huang, Yanlin; Kim, Sun Il; Yu, Young Moon; Seo, Hyo Jin

    2013-09-16

    Niobates CaRNb3O10 (R = La, Sm, Eu, Gd, Dy, Er, Yb, or Y) were prepared by conventional high-temperature solid-state reaction. The formation of a single-phase compound with triple-layered perovskite-type structure was verified through X-ray diffraction (XRD) studies. The luminescence characteristics such as photoluminescence excitation and emission spectra, X-ray-excited luminescence (XEL), Stokes shift, decay curves, and color coordinates were investigated. The niobates can be efficiently excited by UV light and present luminescence behaviors with rich luminescence colors. Under excitation by ultraviolet radiation, CaRNb3O10 (R = La, Gd, Yb, or Y) exhibits strong blue luminescence due to the self-activation center of the octahedral NbO6 groups, even at room temperature. For the materials of composition CaRNb3O10 (R = Sm, Eu, Dy, or Er), the excitation at the host band produces a characteristic luminescence of rare earth ions, indicating a host-guest energy transfer process. CaRNb3O10 (R = Eu) has the strongest luminescence intensity, which can be efficiently excitated by near UV wavelength. It could be suggested to be a potential candidate for the application on near-UV excited white LEDs.

  14. Magnetic Ground States of the Rare-Earth Tripod Kagome Lattice Mg_{2}RE_{3}Sb_{3}O_{14} (RE=Gd,Dy,Er).

    Science.gov (United States)

    Dun, Z L; Trinh, J; Li, K; Lee, M; Chen, K W; Baumbach, R; Hu, Y F; Wang, Y X; Choi, E S; Shastry, B S; Ramirez, A P; Zhou, H D

    2016-04-15

    We present the structural and magnetic properties of a new compound family, Mg_{2}RE_{3}Sb_{3}O_{14} (RE=Gd,Dy,Er), with a hitherto unstudied frustrating lattice, the "tripod kagome" structure. Susceptibility (ac, dc) and specific heat exhibit features that are understood within a simple Luttinger-Tisza-type theory. For RE=Gd, we found long-ranged order (LRO) at 1.65 K, which is consistent with a 120° structure, demonstrating the importance of diople interactions for this 2D Heisenberg system. For RE=Dy, LRO at 0.37 K is related to the "kagome spin ice" physics for a 2D system. This result shows that the tripod kagome structure accelerates the transition to LRO predicted for the related pyrochlore systems. For RE=Er, two transitions, at 80 mK and 2.1 K are observed, suggesting the importance of quantum fluctuations for this putative XY system.

  15. Magnetic and electrical properties of the stannides RE sub 3 Co sub 6 Sn sub 5 (RE Sm, Gd, Tb and Dy)

    CERN Document Server

    Kaczorowski, D; Rogl, P; Romaka, L; Gorelenko, Y

    2003-01-01

    Polycrystalline samples of the ternary intermetallics RE sub 3 Co sub 6 Sn sub 5 (RE Sm, Gd, Tb and Dy) were studied by means of magnetization, dc magnetic susceptibility and electrical resistivity measurements. All these stannides were found to order magnetically at low temperatures. Sm sub 3 Co sub 6 Sn sub 5 is antiferromagnetic below T sub N = 8 K, while Tb sub 3 Co sub 6 Sn sub 5 exhibits ferromagnetic ordering below T sub C = 16 K. The other two compounds show more complex magnetic behaviour with subsequent phase transitions in the ordered regions. For Gd sub 3 Co sub 6 Sn sub 5 one observes the onset of ferromagnetism at T sub C = 25 K, which is followed by a change in the magnetic structure at T sub 1 = 12 K. In the case of Dy sub 3 Co sub 6 Sn sub 5 an antiferromagnetic type of order sets in at T sub N = 7 K, and then a spin structure rearrangement occurs at T sub 1 = 3 K that yields a ferromagnetic component at lower temperatures. All the ternaries studied exhibit metallic-like conductivity with pro...

  16. Crystal chemistry of the orthorhombic Ln{sub 2}TiO{sub 5} compounds with Ln=La, Pr, Nd, Sm, Gd, Tb and Dy

    Energy Technology Data Exchange (ETDEWEB)

    Aughterson, Robert D., E-mail: roa@ansto.gov.au [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Lucas Heights 2234, NSW (Australia); Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney 2006, NSW (Australia); Lumpkin, Gregory R., E-mail: grl@ansto.gov.au [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Lucas Heights 2234, NSW (Australia); Thorogood, Gordon J., E-mail: gjt@ansto.gov.au [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Lucas Heights 2234, NSW (Australia); Zhang, Zhaoming [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Lucas Heights 2234, NSW (Australia); Gault, Baptiste, E-mail: baptiste.gault@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Cairney, Julie M., E-mail: julie.cairney@sydney.edu.au [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney 2006, NSW (Australia)

    2015-07-15

    The crystal structures of seven samples of orthorhombic (Pnma) Ln{sub 2}TiO{sub 5} compounds with Ln=La, Pr, Nd, Sm, Gd, Tb and Dy were refined by Rietveld analysis of synchrotron X-ray powder diffraction (S-XRD) data. With increasing size of the lanthanide cation, the lattice parameters increase systematically: c by only ~1.5% whereas both a and b by ~6% from Dy{sub 2}TiO{sub 5} to La{sub 2}TiO{sub 5}. The mean Ti–O bond length only increases by ~1% with increasing radius of the Ln cation from Gd to La, primarily due to expansion of the pair of Ti–O{sub 3} bonds to opposite corners of the Ti–O{sub 5} square based pyramid polyhedra. For Dy{sub 2}TiO{sub 5} and Tb{sub 2}TiO{sub 5}, a significant variation in Ti–O{sub 1} and Ti–O{sub 4} bond lengths results in an increased deformation of the Ti–O{sub 5} base. The particular configuration consists of large rhombic shaped tunnels and smaller triangular tunnels along the b axis, which have implications for defect formation and migration caused by radiation damage or the ionic conductivity. - Graphical abstract: Figure: The crystallographic study of a systematic series of compounds with nominal stoichiometry Ln{sub 2}TiO{sub 5} (with Ln representing La, Pr, Nd, Sm, Gd, Tb and Dy) and orthorhombic, Pnma, symmetry shows changes in cell parameters which fit a linear trend. However, bond lengths are shown to deviate from trend with compounds containing the smaller, heavier lanthanides. - Highlights: • First fabrication and crystallographic refinement of compound Pr{sub 2}TiO{sub 5}. • First systematic study of the crystallography, using S-XRD, for Ln{sub 2}TiO{sub 5} series. • Cation to anion bonding trends and valence states are investigated. • The densities and band-gaps of the series are experimentally determined.

  17. Investigation of luminescence and laser transition of Dy3+ in Li2O-Gd2O3-Bi2O3-B2O3 glasses

    Science.gov (United States)

    Zaman, F.; Kaewkhao, J.; Srisittipokakun, N.; Wantana, N.; Kim, H. J.; Rooh, G.

    2016-05-01

    The aim of this study is to develop Li2O-Gd2O3-Bi2O3-B2O3 glass doped with different concentration of Dy3+ ions by melt quenching technique for different applications in photonics and laser devices. From the experimental oscillator strength (fexp) of the absorption spectra the JO intensity parameters (Ω λ = 2, 4, 6) have been calculated, and by using these JO intensity parameters various radiative parameters were calculated. By using JO theory the radiative transition probability (AR), radiative lifetime (τR) and branching ratio (βR) for Dy3+ ion have been found. A decrease in lifetimes of the prepared glass by increasing concentration of Dy3+ is because of the energy transfer through cross relaxation and resonant energy transfer channels in the present glass matrix. Using experimental and calculated lifetimes, the quantum efficiency (η) and non-radiative relaxation rates (WNR) of 4F9/2 excited state have been calculated. From emission spectra, effective bandwidths (Δλeff) and emission stimulated emission cross section σ (λp) were found for 4F9/2 → 6HJ (J = 15/2, 13/2, 11/2 and 9/2). Chromaticity results revealed that the CCT values of the LGBiBDy glass samples are in between to those of day light and commercial white light LED sources. Further investigations are under way for the optimization of dopant concentration in the Li2O-Gd2O3-Bi2O3-B2O3 glass.

  18. Evidence for SrHo2O4 and SrDy2O4 as model J1-J2 zigzag chain materials

    DEFF Research Database (Denmark)

    Fennell, A.; Pomjakushin, V. Y.; Uldry, A.

    2014-01-01

    Neutron diffraction and inelastic spectroscopy is used to characterize the magnetic Hamiltonian of SrHo2O4 and SrDy2O4. Through a detailed computation of the crystal-field levels we find site-dependent anisotropic single-ion magnetism in both materials, and diffraction measurements show the prese...

  19. Syntheses and Structures of the New Quaternary Rubidium Selenides Rb Ln2CuSe 4 ( Ln=Sm, Gd, Dy), Rb 1.5Ln2Cu 2.5Se 5 ( Ln=Gd, Dy), and RbSm 2Ag 3Se 5

    Science.gov (United States)

    Huang, Fu Qiang; Ibers, James A.

    2000-05-01

    Six quaternary rubidium selenides RbLn2CuSe4 (Ln=Sm, Gd, Dy), Rb1.5Ln2Cu2.5Se5 (Ln=Gd, Dy), and RbSm2Ag3Se5 have been synthesized at 1073 K with the use of a reactive flux of Rb2Se3. At 153 K all compounds contain four formula units in orthorhombic unit cells. The isostructural compounds RbLn2CuSe4 crystallize in space group Cmcm; the isostructural compounds Rb1.5Ln2Cu2.5Se5 crystallize in space group Pnnm; RbSm2Ag3Se5 crystallizes in space group Cmcm. The cells of RbLn2CuSe4 are (Ln, a, b, c (Å)): Sm, 4.1834(9), 14.308(3), 14.439(3); Gd, 4.1568(8), 14.227(3), 14.409(3); Dy, 4.1237(10), 14.083(4), 14.291(3), and the corresponding R1 indices for the refined structures are 0.023, 0.029, and 0.039. The cells of Rb1.5Ln2Cu2.5Se5 are: Gd, 16.243(3), 16.449(3), 4.0980(7); Dy, 16.120(3), 16.292(3), 4.0610(8), and the R1 indices are 0.036 and 0.043. The cell of RbSm2Ag3Se5 is 4.3223(6), 15.229(2), 17.420(3) Å and the R1 index is 0.025. All six are closely related three-dimensional tunnel structures. Their anionic frameworks are built from LnSe6 octahedra and MSe4 (M=Cu, Ag) tetrahedra. RbLn2CuSe4 contains infinite 1∞[CuSe3] chains of vertex-sharing tetrahedra; Rb1.5Ln2Cu2.5Se5 also contains infinite chains of tetrahedra; and the tunnel in RbSm2Ag3Se5 holds one Rb+ cation in a 10-membered ring consisting of six Ag-Se bonds and four Sm-Se bonds. Rb1.5Dy2Cu2.5Se5, which is paramagnetic, obeys the Curie-Weiss law and has an effective magnetic moment of 10.63(4) μB.

  20. Electric and magnetic properties of Al{sub 86}Ni{sub 8}R{sub 6} (R=Sm, Gd, Ho) alloys in liquid and amorphous states

    Energy Technology Data Exchange (ETDEWEB)

    Sidorov, V. [Ural State Pedagogical University, Ekaterinburg (Russian Federation); Ural Federal University, Ekaterinburg (Russian Federation); Svec, P.; Svec, P.; Janickovic, D. [Institute of Physics SAS, Bratislava (Slovakia); Mikhailov, V. [Ural State Pedagogical University, Ekaterinburg (Russian Federation); Sidorova, E. [Plekhanov Russian University of Economics, Moscow (Russian Federation); Son, L. [Ural State Pedagogical University, Ekaterinburg (Russian Federation); Ural Federal University, Ekaterinburg (Russian Federation)

    2016-06-15

    Electrical resistivity and magnetic susceptibility of Al{sub 86}Ni{sub 8}Sm{sub 6}, Al{sub 86}Ni{sub 8}Gd{sub 6} and Al{sub 86}Ni{sub 8}Ho{sub 6} alloys are studied in a wide temperature range including amorphous, crystalline and liquid states. The negative value of resistivity temperature coefficient in amorphous ribbons is explained by the structural separation starting much before the beginning of their crystallization. The effective magnetic moments per Gd and Ho atoms are found to be essentially lower than for R{sup 3+} ions. The results are discussed in supposition of directed bonds between rare earth and aluminum atoms. - Highlights: • Electric and magnetic properties of Al{sub 86}Ni{sub 8}R{sub 6} alloys are studied experimentally. • The negative value of rtc in amorphous ribbons is explained. • The effective magnetic moments per Gd and Ho are found to be lower than for R{sup 3+} ions.

  1. Synthesis and photoluminescence characteristics of (Y,Gd)BO3:RE (RE = Eu(3+), Ce(3+), Dy(3+) and Tb(3+)) phosphors for blue chip and near-UV white LEDs.

    Science.gov (United States)

    Rangari, V V; Singh, V; Dhoble, S J

    2016-03-01

    A series of Eu(3+)-, Ce(3+)-, Dy(3+)- and Tb(3+)-doped (Y,Gd)BO3 phosphors was synthesized by a solid-state diffusion method. X-Ray diffraction confirmed their hexagonal structure and the scanning electron microscopy results showed crystalline particles. The excitation spectra revealed that (Y,Gd)BO3 phosphors doped with Eu(3+), Ce(3+), Dy(3+) and Tb(3+) are effectively excited with near UV-light of 395 nm/blue light, 364, 351 and 314 nm, respectively. Photoluminescence spectra of Eu(3+)-, Ce(3+)- and Tb(3+)/Dy(3+)-doped phosphor showed intense emission of reddish orange, blue and white light, respectively. The phosphor Y0.60Gd0.38BO3:Ce0.02 showed CIE 1931 color coordinates of (0.158, 0.031) and better color purity compared with commercially available blue BAM:Eu(2+) phosphor. The phosphor (Y,Gd)BO3 doped with Eu(3+), Dy(3+) and Tb(3+) showed CIE 1931 color coordinates of (0.667, 0.332), (0.251, 0.299) and (0.333, 0.391) respectively. Significant photoluminescence characteristics of the prepared phosphors indicate that they might serve as potential candidates for blue chip and near-UV white light-emitting diode applications. Copyright © 2015 John Wiley & Sons, Ltd.

  2. Influence of electron beam irradiation on the structural, electrical and thermal properties of Gd0.5Sr0.5MnO3 and Dy0.5Sr0.5MnO3 manganites

    Science.gov (United States)

    Nagaraja, B. S.; Rao, Ashok; Babu, P. D.; Sanjeev, Ganesh; Okram, G. S.

    2016-01-01

    We present systematic studies on the effect of electron beam irradiation on structural, electrical and thermal properties of Gd0.5Sr0.5MnO3 and Dy0.5Sr0.5MnO3 manganites. The XRD patterns and Rietveld analysis show that the samples remain single phased even after they undergo electron beam irradiation. Both the series of the samples Gd0.5Sr0.5MnO3 and Dy0.5Sr0.5MnO3 show insulating trends in their temperature dependent electrical resistivity, ρ(T) behavior. The resistivity data for both the series of samples (pristine as well as irradiated) indicate that the small polaron hopping model is valid in high temperature region; on contrary, variable range hopping model governs the low temperature regime. Magnetic studies demonstrate that the Neel temperatures of pristine and irradiated samples of Gd0.5Sr0.5MnO3 and Dy0.5Sr0.5MnO3 do not change appreciably when they are subjected to irradiation. Thermo-electrical power is observed to increase with irradiation in Gd0.5Sr0.5MnO3 samples, whereas for Dy0.5Sr0.5MnO3 samples a decrease in thermo-electric power is seen when the samples are irradiated.

  3. Couples Magnetic and Structural Transitions in High-Purity Dy and Gd5SbxGe4-x

    Energy Technology Data Exchange (ETDEWEB)

    Chernyshov, Alexander S. [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    Magnetic materials exhibiting magnetic phase transitions simultaneously with structural rearrangements of their crystal lattices hold a promise for numerous applications including magnetic refrigeration, magnetomechanical devices and sensors. We undertook a detailed study of a single crystal of dysprosium metal, which is a classical example of a system where magnetic and crystallographic sublattices can be either coupled or decoupled from one another. Magnetocaloric effect, magnetization, ac magnetic susceptibility, and heat capacity of high purity single crystals of dysprosium have been investigated over broad temperature and magnetic field intervals with the magnetic field vector parallel to either the a- or c-axes of the crystal. Notable differences in the behavior of the physical properties when compared to Dy samples studied in the past have been observed between 110 K and 125 K, and between 178 K and ~210 K. A plausible mechanism based on the formation of antiferromagnetic clusters in the impure Dy has been suggested in order to explain the reduction of the magnetocaloric effect in the vicinity of the Neel point. Experimental and theoretical investigations of the influence of commensurability effects on the magnetic phase diagram and the value of the magnetocaloric effect have been conducted. The presence of newly found anomalies in the physical properties has been considered as evidence of previously unreported states of Dy. The refined magnetic phase diagram of dysprosium with the magnetic field vector parallel to the a-axis of a crystal has been constructed and discussed. The magnetic and crystallographic properties of Gd5SbxGe4-x pseudo-binary system were studied by x-ray diffraction (at room temperature), heat capacity, ac-magnetic susceptibility, and magnetization in the temperature interval 5-320 K in magnetic fields up to 100 kOe. The magnetic properties of three composition (x = 0.5, 1,2) were examined in detail. The

  4. Luminescence characteristic of RE (RE = Pr, Sm, Eu, Tb, Dy) and energy levels of lanthanide ions in Gd5Si3O12N

    Science.gov (United States)

    Zhang, Zhi-Jun; Yang, Woochul

    2017-10-01

    Polycrystalline Gd5Si3O12N: RE (RE = Pr, Sm, Eu, Tb and Dy) phosphors have been synthesized via a solid-state reaction method at high temperature, and their photoluminescence properties were studied. The absorption peak at about 230 nm is attributed to the host absorption. For the Pr3+-doped sample, the typical excitation lines located at 273 nm originating from the 8S7/2 → 6IJ (J = 5/2, 7/2) transitions of the Gd3+ ions were observed in the excitation spectra. Upon excitation at 227 nm UV light, the 4f15d → 4f2 emission band (350-450 nm) and typical 4f2 → 4f2 emission lines (450-700 nm) assigned to Pr3+ were observed. The Sm3+-doped sample exhibits a bright red emission owing to the 4G5/2 → 6HJ (J = 5/2, 7/2 and 9/2) transitions. However, the charge transfer band of Sm3+ was not observed in the excitation spectrum. There is a broad band from 200 to 350 nm originating from the charge transfer transition (CT) of the Eu3+ (O2-/N3- → Eu3+) in the excitation spectra, and the strongest peak in the emission spectra located at 615 nm is due to the electric-dipole 5D0 → 7F2 transition of Eu3+. For the Tb3+-doped sample, it shows 5D3 →7FJ (J = 5, 4, 3, 2) blue line emissions and 5D4 → 7FJ (J = 6, 5, 4, 3) green line emissions under the excitation of Tb3+. The Dy3+-activated sample upon excitation at 349 and 386 nm UV light shows blue-green and orange-red emission lines originating from 4F9/2 → 6HJ (J = 15/2, 13/2) transitions. In addition, the energy transfer from the host lattice to the luminescence activators (i.e. Pr3+, Sm3+, Eu3+, Tb3+, Dy3+) has been confirmed. In addition, the energy level diagram including the 4f and 5d energy levels of all Ln2+ and Ln3+ ions relative to the valence and conduction band of Gd5Si3O12N were constructed and discussed.

  5. Structural, magnetic and electronic transport studies of RAgSn2 compounds (R = Y, Tb, Dy, Ho and Er) with Cu3Au-type

    Indian Academy of Sciences (India)

    L Romaka; V V Romaka; I Lototska; A Szytula; B Kuzhel; A Zarzycki; E K Hlil; D Fruchart

    2013-12-01

    RAgSn2 compounds, where R = Y, Tb, Dy, Ho and Er, were synthesized by arc-melting and subsequent annealing at 870 K. The formation of cubic phases with Cu3Au-type structure (space group $\\bar{3}$) was studied. Magnetic property measurements showed that in paramagnetic state, the compounds with magnetic rareearth atoms are Curie–Weiss paramagnets and order antiferromagnetically at low temperatures. YAgSn2 is a Pauli paramagnet in 100–300 K temperature range. The electrical properties of RAgSn2 compounds were investigated by means of electrical resistivity and Seebeck coefficient measurements in 4.2–300 K temperature range. All investigated compounds exhibit metallic type of conductivity. Electronic structure calculations based on full potential linearized augmented plane wave (FLAPW)method is also carried out to probe themagnetic and electronic structures of RAgSn2 compounds. Comparisons between experimental data and calculations are discussed.

  6. Structural and magnetic phase transitions of kagome-like compounds REBaCo{sub 4}O{sub 7} (RE=Dy, Ho, Er, Tm, Yb, Lu)

    Energy Technology Data Exchange (ETDEWEB)

    Markina, M., E-mail: markina@lt.phys.msu.r [Low Temperature Physics Department, Moscow State University, Moscow 119992 (Russian Federation); Vasiliev, A.N. [Low Temperature Physics Department, Moscow State University, Moscow 119992 (Russian Federation); Nakayama, N.; Mizota, T. [Department of Advanced Materials Science and Engineering, Faculty of Engineering, Yamaguchi University, Ube 755-8611 (Japan); Yeda, Y. [Materials Design and Characterization Laboratory, Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581 (Japan)

    2010-05-15

    In a temperature range 5-300 K the specific heat C(T) on a new mixed valence cobalt oxides REBaCo{sub 4}O{sub 7} (RE=Dy, Ho, Er, Tm, Yb, Lu) was investigated. The first-order structural phase transitions from hexagonal P6{sub 3}mc to orthorhombic Cmc{sub 2}1 phase was indicated by a peak-like anomaly in C(T) curves at T{sub S}approx160, 178, 224, and 280 K for RE=Lu, Yb, Tm, and Er correspondingly. The magnetic phase transitions was indicated as the changes of slope on the C(T) curves were found at corresponding temperatures: T{sub N}approx50, 74, 98, and 98 K for RE=Lu, Yb, Tm, and Er, correspondingly.

  7. Full potential calculations and atom in molecule analysis of the bonding properties of perovskites Borides XRh3B (X=Dy, Ho, Er

    Directory of Open Access Journals (Sweden)

    Ouahrani T.

    2013-03-01

    Full Text Available ab initio calculations were performed for the cubic perovskites Borides XRh3B, (X=Dy, Ho, Er. In this work, we have used the augmented plane-wave plus local orbital method to compute the equilibrium structural parameters and electronic structure of densities of states, as well as for the first time, prediction of the thermo-elastic properties of these crystals are presented. The chemical bonding of these compounds has been investigated by using of topological analyses grounded in the theory of atoms in molecules (AIM. All of the electron density critical points in the unit cell were systematically calculated in order to calculate basins interaction of each atoms and give exact classification of the bonding character.

  8. Spectral intensities for the Cs{sub 2}NaDyCl{sub 6} and Cs{sub 2}NaHoCl{sub 6} systems

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo, Roberto; Navarro, Gustavo [Universidad Mayor, Manuel Montt 367, Santiago (Chile); Soto-Bubert, Andres [Universidad San Sebastian, Ernesto Pinto Lagarrigue 47, Santiago (Chile)], E-mail: roberto.acevedo@umayor.cl

    2008-11-01

    The main goal of this research work is to rationalize the rich vibronic structure of two lanthanide type crystals, such as Cs{sub 2}NaDyCl{sub 6} and Cs{sub 2}NaHoCl{sub 6}, which belongs to the space group Fm3m(O{sub h}{sup 5}). These systems are known to be highly relativistic and as a consequence, major corrections to previous calculation models, are due to be taken into account so as to rationalize the observed spectral intensities. Our emphasis has been placed upon both the origin and Nature of the physical model to be employed as well as on the strategy to be followed in order to improve our current understanding of the intensity mechanism with reference to general radiative transitions for complex systems, in the solid state physics.

  9. Electronic structure of RSn1.1Ge0.9 (R = Dy, Ho) ternary compounds: Band calculation and optical properties

    Science.gov (United States)

    Knyazev, Yu. V.; Lukoyanov, A. V.; Kuz'min, Yu. I.; Gupta, S.; Suresh, K. G.

    2017-09-01

    The results of investigations of the electronic structure and optical properties of the compounds DySn1.1Ge0.9 and HoSn1.1Ge0.9 are presented. Our spin-polarized calculations of the electronic structure are carried out in the local spin density approximation with correction for strong electronic correlations (LSDA+U method) in the 4f shell of the rare-earth ion. In the wavelength range 0.22-15 μm, the optical constants of the intermetallic compounds were measured by the ellipsometric method, and a number of spectral and electronic characteristics are determined. Based on the calculated densities of states, the structural features of the optical conductivity in the region of interband light absorption are interpreted.

  10. Growth, thermal and spectral properties of Tm{sup 3+}, Ho{sup 3+} co-doped NaGd(MoO{sub 4}){sub 2} Crystal

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chunhao [Key Laboratory of Optoelectronic Information and Sensing Technologies, Guangdong Higher Education Institutes, Guangzhou 510632 (China); Institute of Optoelectronic Engineering, Jinan University, Guangzhou 510632 (China); Yin, Hao, E-mail: yinhaoemail@jnu.edu.cn [Institute of Optoelectronic Engineering, Jinan University, Guangzhou 510632 (China); Key Laboratory of Optoelectronic Materials Chemistry and Physics, CAS, Fuzhou 350002 (China); Li, Anming; Wu, Yonghua; Zhu, Siqi [Key Laboratory of Optoelectronic Information and Sensing Technologies, Guangdong Higher Education Institutes, Guangzhou 510632 (China); Institute of Optoelectronic Engineering, Jinan University, Guangzhou 510632 (China); Chen, Zhenqiang, E-mail: tzqchen@jnu.edu.cn [Key Laboratory of Optoelectronic Information and Sensing Technologies, Guangdong Higher Education Institutes, Guangzhou 510632 (China); Institute of Optoelectronic Engineering, Jinan University, Guangzhou 510632 (China); Zhang, Ge [Key Laboratory of Optoelectronic Materials Chemistry and Physics, CAS, Fuzhou 350002 (China); Su, Kang [Key Laboratory of Optoelectronic Information and Sensing Technologies, Guangdong Higher Education Institutes, Guangzhou 510632 (China); Institute of Optoelectronic Engineering, Jinan University, Guangzhou 510632 (China)

    2014-12-05

    Highlights: • The Tm{sup 3+}/Ho{sup 3+}:NaGd(MoO{sub 4}){sub 2} crystal was grown by Czochralski method. • The optical characterizes and energy transfer process of Tm{sup 3+}/Ho{sup 3+}:NaGd(MoO{sub 4}){sub 2} crystal were studied. • This crystal exhibits a large absorption cross-section at 796 nm and broad emission band around 2 μm. • The results indicate that the crystal may be regarded as a potential solid-state laser material. - Abstract: A Tm{sup 3+}/Ho{sup 3+}:NaGd(MoO{sub 4}){sub 2} crystal was grown by the Czochralski method. The XRD results matched standard data from JCPDS file, which accorded with scheelite structure with an I41/a space group. Thermal properties of crystal were analyzed by using the TG–DSC curve. The melting point and specific heat are 1182 °C and 0.5 J/g K at 300 K, respectively. The Spectral properties of the Tm{sup 3+}/Ho{sup 3+}:NaGd(MoO{sub 4}){sub 2} crystal were investigated, including room temperature absorption spectrum and fluorescence spectrum. The absorption cross-section of Tm{sup 3+} at 796 nm is 4.33 × 10{sup −20} cm{sup 2} with pertinent full widths at half maximum (FWHM) of 10 nm. The intensity parameters, spontaneous emission probability, fluorescence branching ratios and radiative lifetimes were calculated by Judd–Ofelt theory. The emission cross-sections are 1.47 × 10{sup −20} cm{sup 2} and 1.36 × 10{sup −20} cm{sup 2} for Tm{sup 3+} at 1850 nm and Ho{sup 3+} at 2000 nm respectively. The lifetime of {sup 5}I{sub 7} → {sup 5}I{sub 8} (Ho{sup 3+}) was 4.263 ms.

  11. Structural and thermoelectric properties of BaRCo{sub 4}O{sub 7} (R = Dy, Ho, Er, Tm, Yb, and Lu)

    Energy Technology Data Exchange (ETDEWEB)

    Wong-Ng, W.; Yan, Y.; Liu, G. [Ceramics Division, NIST, Gaithersburg, Maryland 20899 (United States); Xie, W.; Tritt, T. [Department of Physics, Clemson University, Greensville, South Carolina 29634 (United States); Kaduk, J. [Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Thomas, E. [Air Force Research Laboratory, Wright Pattersen, Ohio 45433 (United States)

    2011-12-01

    The structure and thermoelectric properties of a series of barium lanthanide cobaltites, BaRCo{sub 4}O{sub 7} (R = Dy, Ho, Er, Tm, Yb, and Lu), which were prepared using the spark plasma synthesis technique, have been investigated. The space group of these compounds was re-determined and confirmed to be P31c instead of the reported P6{sub 3}mc. The lattice parameters a and c range from 6.26279(2) Angst to 6.31181(6) Angst , and from 10.22468(6) Angst to 10.24446(15) Angst for R = Lu to Dy, respectively. The crystal structure of BaRCo{sub 4}O{sub 7} is built up from Kagome sheets of CoO{sub 4} tetrahedra, linked by triangular layers of CoO{sub 4} tetrahedra. The values of figure of merit (ZT) of the BaRCo{sub 4}O{sub 7} samples were determined to be around 0.02 at 800 K. X-ray diffraction patterns of these samples have been determined and submitted to the Powder Diffraction File.

  12. Optimization of magnetic properties of sintered (SmGdDy)(Co, Fe, Cu, Zr){sub z} magnets by Dy–Co addition

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L. [Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Pan, D.L. [Ningbo Co-star Materials Hi-Tech Co. Ltd., Ningbo 315145 (China); Liu, Z., E-mail: zliu@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhang, H.W.; Li, M.; Chen, R.J.; Liu, X.M. [Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Yan, A.R., E-mail: aruyan@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Lee, Don [Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); University of Dayton, Dayton, OH 45469 (United States); Li, W. [Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2015-01-15

    Liquid phase sintering is used to optimize the magnetic properties and temperature stability of (SmGdDy)(Co, Fe, Cu, Zr){sub z} sintered magnet. DyCo{sub 0.51} and Sm{sub 0.67}Dy{sub 0.11}Gd{sub 0.22}(Co{sub 0.693}Fe{sub 0.201}Cu{sub 0.081}Zr{sub 0.0252}){sub 7.94} alloys are chosen as liquid phase and main phase, respectively. (SmGdDy)(Co, Fe, Cu, Zr){sub z} permanent magnets are prepared with different content of liquid phase. XRD analysis shows that all magnets consist of Th{sub 2}Zn{sub 17}-type phase and CaCu{sub 5}-type phase. Cellular structure studies indicate that the H1-5 cell boundary phase shifts gradually from thin and part of discontinuous to thick and continuous. The cell size decreases with the increase of the content of liquid phase. In addition, the Cu content in cell boundary phase is getting lower with the increase of LP adding ratio. The homogeneous and continuous cellular structure is got when the adding ratio of liquid phase is 3 wt% and the highest intrinsic coercivity is achieved at room temperature (23.88 kOe) and 200 °C (12.06 kOe). It’s interesting to find that temperature dependence of remanence (α) and the temperature dependence of intrinsic coercivity (β) can be optimized with the increase of the content of liquid phase, in which the α(20–100 °C) and β(20–200 °C) are −0.0075%/°C and −0.140%/°C for the magnet with 5 wt% liquid phase, and −0.016%/°C and −0.322%/°C for the magnet with 1 wt% liquid phase. - Highlights: • 2–17 Type Sm–Co sintered magnets with low remanence temperature coefficient have been further optimized by adding DyCo{sub 0.51} liquid phase. • Cellular structure shows that the H1-5 cell boundary phase shifts gradually from thin and part of discontinuous to thick and continuous. And the cell size decreases with the increase of liquid phase content. In addition, the Cu content in cell boundary phase is getting lower with the increase of LP adding ratio. • With the increase of LP content

  13. Age hardening characteristics and mechanical properties of Mg-3.5Dy-4.0Gd-3.1Nd-0.4Zr alloy

    Institute of Scientific and Technical Information of China (English)

    LI De-hui; DONG Jie; ZENG Xiao-qin; LU Chen; DING Wen-jiang

    2006-01-01

    Age hardening characteristic and tensile property of Mg-3.5Dy-4.0Gd-3.1Nd-0.4Zr alloy were investigated. The alloy exhibits a considerable age hardening effect up to 250 ℃. Increasing the aging temperature leads to a shorter aging time to reach the peak hardness and a lower peak hardness. The tensile results show that the peak-aged specimens have higher tensile strength at the temperature below 200℃. However, with the increase of temperature further, the tensile strength decreases dramatically and elongation increases drastically. The loss in tensile strength and increase in elongation at high temperature are possibly associated with the instability of secondary precipitates. The fracture mechanism of alloy transfers from intergranular to transgranular with the increase of experimental temperature.

  14. Spectrophotometric and pH-Metric Studies of Ce(III, Dy(III, Gd(III,Yb(III and Pr(III Metal Complexes with Rifampicin

    Directory of Open Access Journals (Sweden)

    A. N. Sonar

    2011-01-01

    Full Text Available The metal-ligand and proton-ligand stability constant of Ce(III, Dy(III, Gd(III,Yb(III and Pr(III metals with substituted heterocyclic drug (Rifampicin were determined at various ionic strength by pH metric titration. NaClO4 was used to maintain ionic strength of solution. The results obtained were extrapolated to the zero ionic strength using an equation with one individual parameter. The thermodynamic stability constant of the complexes were also calculated. The formation of complexes has been studied by Job’s method. The results obtained were of stability constants by pH metric method is confirmed by Job’s method.

  15. Heat capacities, magnetic properties, and resistivities of ternary RPdBi alloys where R = La, Nd, Gd, Dy, Er, and Lu

    Energy Technology Data Exchange (ETDEWEB)

    Riedemann, T.M.

    1996-05-01

    Over the past four and a half decades research on the rare earths, their compounds, and their alloys has yielded significant insights into the nature of materials. The rare earths can be used to systematically study a series of alloys or compounds. Magnetic ordering, crystalline fields, spin fluctuations, the magnetocaloric effect, and magnetostriction are a small sample of phenomena studied that are exhibited by the rare earth family. A significant portion of research has been conducted on the abundant RM{sub 2} and RM phases, where R is the rare earth and M is a transition metal. The natural progression of science has led to the study of related RMX ternary phases, where X is either another transition metal or semimetal. There are now over 1,000 known RMX phases. The focus of this study is on RPdBi where R = La, Nd, Gd, Dy, Er, and Lu. Their heat capacities, magnetic properties, and resistivities are studied.

  16. Features of magnetic and thermal properties of R(Co1-xFex)2 (x≤0.16) quasibinary compounds with R=Dy, Ho, Er

    Science.gov (United States)

    Anikin, Maksim; Tarasov, Evgeniy; Kudrevatykh, Nikolay; Inishev, Aleksander; Semkin, Mikhail; Volegov, Aleksey; Zinin, Aleksander

    2016-11-01

    In this work the results of measurements of high field susceptibility, paraprocess susceptibility and thermal properties of R(Co1-xFex)2 intermetallic compounds (R=Dy, Ho, Er and x=(0-0.16)) are presented (heat capacity and magnetocaloric effect (MCE)). A magnetic structure of the Ho(Co0.88Fe0.12)2 at 293 K and 78 K was studied by neutron powder diffraction. Some peculiarities of a high-field susceptibility were revealed at low temperatures and around the Curie point (TC). In temperature range lower than TC by (100-150) K, magnetic contributions to a zero-field heat capacity were found. Studying MCE in wide temperatures range, the large change of the entropy magnetic contribution (°S) was observed which correlates with °T phenomenon. In particular, for the Er(Co0.84Fe0.16)2 compound the °S value at low temperatures is six times higher than that at Curie point. The possible reasons of such behavior were discussed.

  17. Syntheses, structures, and magnetic properties of a family of heterometallic heptanuclear [Cu5Ln2] (Ln = Y(III), Lu(III), Dy(III), Ho(III), Er(III), and Yb(III)) complexes: observation of SMM behavior for the Dy(III) and Ho(III) analogues.

    Science.gov (United States)

    Chandrasekhar, Vadapalli; Dey, Atanu; Das, Sourav; Rouzières, Mathieu; Clérac, Rodolphe

    2013-03-04

    Sequential reaction of the multisite coordination ligand (LH3) with Cu(OAc)2·H2O, followed by the addition of a rare-earth(III) nitrate salt in the presence of triethylamine, afforded a series of heterometallic heptanuclear complexes containing a [Cu5Ln2] core {Ln = Y(1), Lu(2), Dy(3), Ho(4), Er(5), and Yb(6)}. Single-crystal X-ray crystallography reveals that all the complexes are dicationic species that crystallize with two nitrate anions to compensate the charge. The heptanuclear aggregates in 1-6 are centrosymmetrical complexes, with a hexagonal-like arrangement of six peripheral metal ions (two rare-earth and four copper) around a central Cu(II) situated on a crystallographic inversion center. An all-oxygen environment is found to be present around the rare-earth metal ions, which adopt a distorted square-antiprismatic geometry. Three different Cu(II) sites are present in the heptanuclear complexes: two possess a distorted octahedral coordination sphere while the remaining one displays a distorted square-pyramidal geometry. Detailed static and dynamic magnetic properties of all the complexes have been studied and revealed the single-molecule magnet behavior of the Dy(III) and Ho(III) derivatives.

  18. Chemical co-precipitation synthesis and photoluminescence of LnP {sub x}V{sub 1-x}O{sub 4}:Dy{sup 3+} (Ln = Gd, La) derived from assembling hybrid precursors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Bing [Department of Chemistry, Tongji University, Shanghai 200092 (China)]. E-mail: byan@tongji.edu.cn; Su, Xue-Qing [Department of Chemistry, Tongji University, Shanghai 200092 (China)

    2007-04-04

    A novel synthesis technology was applied to obtain GdP {sub x}V{sub 1-x}O{sub 4}:Dy{sup 3+} (x = 0.2, 0.3, 0.4, 0.5, 0.6, 0.7) and LaP {sub x}V{sub 1-x}O{sub 4}:Dy{sup 3+} (x = 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8) phosphors for the first time. And the doping concentration of Dy{sup 3+} ions was 3 mol.% in the two systems. Besides this, GdVO{sub 4} and LaVO{sub 4} doped with different concentration of Dy{sup 3+} ions were also synthesized. The rare earth coordination polymers with salicylic acid were used as precursors and the polyethylene glycol (PEG) was used as dispersing media. By an in situ co-precipitation process, we obtained the hybrid precursors. Both XRD and SEM indicated that the particles present good crystalline state, whose crystalline grain sizes were in the range of around 0.5-1 {mu}m. The optical properties of all the powder presented that the characteristic transitions of Dy{sup 3+} due to {sup 4}F{sub 9/2} {sup {yields}} {sup 6}H{sub 15/2} (blue) and {sup 4}F{sub 9/2} {sup {yields}} {sup 6}H{sub 13/2} (yellow) were detected. Besides this, in the system of GdP {sub x}V{sub 1-x}O{sub 4}:Dy{sup 3+}, the yellow-to-blue intensity ration (Y/B) depended on the value of P/V greatly, with the increasing of x value, the Y/B decreasing.

  19. Magnetoresistance, susceptibility and magnetization measurements on RNiBC compounds (R = Er, Ho, Dy, Tb, and Gd)

    Science.gov (United States)

    Tróchez, J. C.; Sánchez, D. R.; Giordanengo, B.; Fontes, M. B.; Continentino, Múcio; Baggio-Saitovitch, E. M.

    1997-08-01

    We studied magnetic behavior of the RNiBC compounds by magnetic and transport measurements. At low temperatures, each compound has different magnetic structure. Magnetoresistivity data are in good accordance with theory of magnetic elementary interactions, susceptibility reveals the magnetic transition and Curie Weiss behavior and magnetization shows low value of the saturation compared with the free R+3 ion that confirm that crystalline electric field is strong as in the RNi2B2C series.

  20. Facile patterning of luminescent GdVO{sub 4}:Ln (Ln = Eu{sup 3+}, Dy{sup 3+}, Sm{sup 3+}) thin films by microcontact printing process

    Energy Technology Data Exchange (ETDEWEB)

    Wang Dong; Yang Piaoping; Cheng Ziyong, E-mail: zycheng@ciac.jl.cn; Wang Wenxin; Ma Pingan; Zhai Xuefeng; Lin Jun, E-mail: jlin@ciac.jl.cn [Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, State Key Laboratory of Rare Earth Resource Utilization (China)

    2012-01-15

    Ordered arrays of luminescent GdVO{sub 4}:Ln (Ln = Eu{sup 3+}, Dy{sup 3+}, Sm{sup 3+}) films with dot patterns have been successfully fabricated via microcontact printing method. The soft-lithography process utilizes a PDMS elastomeric mold as the stamp combined with a Pechini-type sol-gel process to produce luminescent patterns on quartz plates, in which a GdVO{sub 4}:Ln (Ln = Eu{sup 3+}, Dy{sup 3+}, Sm{sup 3+}) precursor solution was employed as ink. The ordered luminescent GdVO{sub 4}:Ln patterns were revealed by optical microscopy and their microstructure, consisting of nanometer-scale particles, as demonstrated by scanning electronic microscopy observations. In addition, photoluminescence and cathodoluminescence were carried out to characterize the patterned GdVO{sub 4}:Ln (Ln = Eu{sup 3+}, Dy{sup 3+}, Sm{sup 3+}) samples. Upon UV-light or electron-beam irradiation, the rare earth ions Eu{sup 3+}, Dy{sup 3+}, and Sm{sup 3+} in the crystalline GdVO{sub 4} host show their characteristic transitions dominated by {sup 5}D{sub 0}-{sup 7}F{sub 2}, {sup 4}F{sub 9/2}-{sup 6}H{sub 13/2} ,and {sup 4}G{sub 5/2}-{sup 6}H{sub 7/2}, respectively. These results make the combining soft lithography with a Pechini-type sol-gel route have potential applications as rare-earth luminescent pixels for next-generation field-emission display devices.

  1. Suppression of the superconducting transition of RFeAsO1-xFx ( R=Tb , Dy, and Ho)

    Science.gov (United States)

    Rodgers, Jennifer A.; Penny, George B. S.; Marcinkova, Andrea; Bos, Jan-Willem G.; Sokolov, Dmitry A.; Kusmartseva, Anna; Huxley, Andrew D.; Attfield, J. Paul

    2009-08-01

    A suppression of superconductivity in the late rare-earth RFeAsO1-xFx materials is reported. The maximum critical temperature (Tc) decreases from 51 K for R=Tb to 36 K for HoFeAsO0.9F0.1 , which has been synthesized under 10 GPa pressure. This suppression is driven by a decrease in the Fe-As-Fe angle below an optimum value of 110.6° , as the angle decreases linearly with unit-cell volume (V) across the RFeAsO1-xFx series. A crossover in electronic structure around this optimum geometry is evidenced by a change in sign of the compositional dTc/dV , from negative values for previously reported large R materials to positive for HoFeAsO0.9F0.1 .

  2. Large magnetocaloric effect in Ln{sub 0.5}Ca{sub 0.5}MnO{sub 3} (Ln=Gd, DY) compounds: Conseqence of magnetic precursor effect of rare earth ions

    Energy Technology Data Exchange (ETDEWEB)

    Das, Kalipada, E-mail: kalipada.das@saha.ac.in; Paramanik, Tapas; Das, I.

    2015-01-15

    Magnetic, specific heat and magnetocaloric studies have been performed on rare earth calcium manganites; Ln{sub 0.5}Ca{sub 0.5}MnO{sub 3} (Ln=Gd, Dy). The observed isothermal magnetic entropy change is fairly large at low temperature in the manganites family, which is attributed to the magnetic precursor effect of rare-earth ions. For Gd{sub 0.5}Ca{sub 0.5}MnO{sub 3}, the isothermal magnetic entropy change (−ΔS) at 4 K, obtained for 7 T magnetic field, is as high as 22.8 J/kg K. On the other hand, −ΔS is 8.5 J/kg K for Dy{sub 0.5}Ca{sub 0.5}MnO{sub 3}. The large value of magnetic entropy change at the cryogenic temperature range for these compounds is interesting from application point of view. - Highlights: • No long range magnetic ordering of Gd{sub 0.5}Ca{sub 0.5}MnO{sub 3} and Dy{sub 0.5}Ca{sub 0.5}MnO{sub 3} has been observed in magnetization measurement down to T=2 K still these compounds show large magnetocaloric effect. • Specific heat of the compounds in absence of magnetic field increases at low temperature (down to 3 K). • Results are analyzed considering magnetic precursor effect of rare earth ions (Gd and Dy ions)

  3. Effect of rare earth additions on magnetic properties of Fe{sub 82}Nb{sub 2}B{sub 14}RE{sub 2} (RE = Y, Gd, Tb and Dy) amorphous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chrobak, A., E-mail: artur.chrobak@us.edu.pl [Institute of Physics, Silesian University, 4 Uniwersytecka, 40-007 Katowice (Poland); Nosenko, V. [G.V. Kurdyumov Institute for Physics of Metals, NAS of Ukraine, Vernadsky ave. 36, 03142 Kyiv (Ukraine); Haneczok, G. [University of Silesia, Institute of Materials Science, 12 Bankowa, 40-007 Katowice (Poland); Boichyshyn, L.; Kotur, B. [Ivan Franko National University of Lviv, Kyryla and Mefodia St. 6, 79005 Lviv (Ukraine); Bajorek, A. [Institute of Physics, Silesian University, 4 Uniwersytecka, 40-007 Katowice (Poland); Zivotsky, O.; Hendrych, A. [Technical University of Ostrava, Institute of Physics, 17. listopadu 15, 708 33 Ostrava-Poruba (Czech Republic)

    2011-10-17

    Highlights: {yields} We studied magnetic properties of Fe{sub 82}Nb{sub 2}B{sub 14}RE{sub 2} (RE=Y,Gd,Tb,Dy) amorphous alloys. {yields} In a comparison with Fe{sub 82}Nb{sub 2}B{sub 14}Y{sub 2} alloy the rare earth editions cause an increase of the Curie temperature and a decrease of magnetic moment per magnetic atom. {yields} Doping of Tb and Dy lead to a strong decrease of magnetic permeability and a formation of low dimensional finger-print magnetic domains. - Abstract: In the present paper the influence of RE alloying additions (Y, Gd, Tb and Dy) on magnetic properties (Curie temperatures, low temperature magnetization, zero field cooling-field cooling curves, domain structure, room temperature magnetostriction and magnetic permeability) of amorphous alloys of type Fe{sub 82}Nb{sub 2}B{sub 14}RE{sub 2} are carefully examined. It was shown that substituting of yttrium atoms by magnetic elements, i.e. Gd, Tb and Dy leads to (i) an increase of the Curie temperature of amorphous phase from 416 K (for Fe{sub 82}Nb{sub 2}B{sub 14}Y{sub 2}) to 450 K (for Fe{sub 82}Nb{sub 2}B{sub 14}Gd{sub 2}) and (ii) a decrease of magnetization in saturation (magnetic field 7 T) which can be explained by antiferromagnetic Fe-RE coupling resulting in a decrease of magnetic moment calculated per magnetic atom from 2.00 {mu}{sub B} for the Fe{sub 82}Nb{sub 2}B{sub 14}Y{sub 2} alloy (Fe in amorphous phase) to 1.51 {mu}{sub B} for the Fe{sub 82}Nb{sub 2}B{sub 14}Tb{sub 2} alloy. It was concluded that Tb and Dy alloying additions introduce a local magnetic anisotropy responsible for significant decrease of initial magnetic permeability (about 5 times in relation to Fe{sub 82}Nb{sub 2}B{sub 14}Y{sub 2} or Fe{sub 82}Nb{sub 2}B{sub 14}Gd{sub 2} alloy), increase of magnetic irreversibility effect measured at 2 K (about 10 times in relation to the same alloys) and appearing of the finger-print magnetic domain regions (not observed for the Fe{sub 82}Nb{sub 2}B{sub 14}Y{sub 2} and Fe{sub 82}Nb

  4. Structural elucidation and magnetic behavior evaluation of rare earth (La, Nd, Gd, Tb, Dy) doped BaCoNi-X hexagonal nano-sized ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Majeed, Abdul, E-mail: abdulmajeed2276@gmail.com [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Khan, Muhammad Azhar, E-mail: azhar.khan@iub.edu.pk [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Raheem, Faseeh ur; Hussain, Altaf; Iqbal, F. [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Murtaza, Ghulam [Centre for Advanced Studies in Physics, Government College University, Lahore 54000 (Pakistan); Akhtar, Majid Niaz [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Shakir, Imran [Deanship of Scientific Research, College of Engineering, King Saud University, PO Box 800, Riyadh 11421 (Saudi Arabia); Warsi, Muhammad Farooq [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

    2016-06-15

    Rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route, which is a fast chemistry route for obtaining nano-sized ferrite powders. These nanomaterials were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), as well as vibrating sample magnetometer (VSM). The XRD analysis exhibited that all the samples crystallized into single X-type hexagonal phase. The crystalline size calculated by Scherrer's formula was found in the range 7–19 nm. The variations in lattice parameters elucidated the incorporation of rare-earth cations in these nanomaterials. FTIR absorption spectra of these X-type ferrites were investigated in the wave number range 500–2400 cm{sup −1.} Each spectrum exhibited absorption bands in the low wave number range, thereby confirming the X-type hexagonal structure. The enhancement in the coercivity was observed with the doping of rare-earth cations. The saturation magnetization was lowered owing to the redistribution of rare-earth cations on the octahedral site (3b{sub VI}). The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Graphical abstract: Nano-sized rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route and the crystallite size was found in the range 7–19 nm. The enhancement in the coercivity was observed with the doping of rare-earth cations. The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Highlights: • Micro-emulsion route was used to synthesize Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} ferrites. • The crystallite size was found

  5. Suitability of the rare-earth compounds Dy2Ti2O7 and Gd3Al5O12 for low temperature (4K-20K) magnetic refrigeration cycle

    Science.gov (United States)

    Flood, D. J.

    1973-01-01

    Measurements were made of the magnetic entropy and magnetization of powered samples of the compounds Dy2Ti2O7 and Gd3Al5O12. The magnetization was measured for temperatures at and below 4.2 K, in applied fields ranging to 7.0 tesla. Isothermal changes in magnetic entropy were measured for temperatures from 1.2 to 20 K, in applied fields up to 10 tesla. The results of the measurements are consistent with a doublet ground state for Dy2Ti2O7, and an eight-fold degenerate ground state for Gd3Al5O12. Absolute values of magnetic entropy have been obtained at the lower temperatures, permitting the isotherms to be properly located in the S-H plane with the use of adiabatic magnetization data. The iso-field lines in the S-T plane were determined. The results indicate that Dy2Ti2O7 can absorb a maximum of 71 + or - 4 joules/kg of heat at 4.2 K, while Gd3Al5O12 can absorb 233 + or - joules/kg at the same temperature. The large difference between the two is most likely a result of crystal field interactions in the dysoprosium compound. Both materials can be cycled adiabatically between 4.2 and 20 K.

  6. Development of uniaxial magnetocrystalline anisotropy in SrFe{sub 12−x}(DyGd){sub x}O{sub 19} thin film synthesized by incorporation of high coercivity nanoparticles in sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Ghasemi, Ali, E-mail: ali13912001@yahoo.com

    2014-06-01

    SrFe{sub 12−x}(DyGd){sub x}O{sub 19} thin films with x=0–2.5 were synthesized by a sol–gel method on thermally oxidized silicon wafer (Si/SiO{sub 2}). XRD patterns and FE-SEM micrographs demonstrated that single phase c-axis hexagonal ferrite films with rather narrow grain size distribution were obtained. It was found that the grain size is decreased from about 110 nm (for the film with no substitution) to 35 nm (for the film with the highest amount of substitution cations). AFM micrographs exhibited that the surface roughness decreases with an increase in substitution content. It was found from the VSM graphs that with an increase in substitution contents coercivity and saturation of magnetization increase. The maximum saturation of magnetization and coercivity at perpendicular direction were 250 emu/g and 5.5 kOe, respectively. - Highlights: • SrFe{sub 12−x}(DyGd){sub x}O{sub 19} ferrite thin films were successfully synthesized by a sol–gel method. • With an increase in Dy-Gd substitution coercivity and saturation of magnetization increase. • The existence of perpendicular magnetic anisotropy was confirmed by plotting magnetization curve.

  7. Performance evaluation of ZnGeP2 optical parametric oscillator pumped by a Q-switched Tm,Ho:GdVO4 laser

    Institute of Scientific and Technical Information of China (English)

    Baoquan Yao; Youlun Ju; Yuezhu Wang; Wanjun He

    2008-01-01

    A doubly resonant ZnGeP2 (ZGP) optical parametric oscillator (OPO) pumped by a novel Tm,Ho:GdVO4 laser was demonstrated. Cryogenic Tm(5 at.-%), Ho(0.5 at.-%):GdVO4 laser with high pulse repetition frequency (PRF) of 10 kHz at 2.05 μm was employed as pumping source of ZGP OPO. The 15-mm-long ZGP crystal, 55° cut for I-type phase-matching with low absorption coefficient less than 0.05 cm-1 at 2-μm, was placed in a plano-plano cavity with resonator length of 30 mm. The ZGP OPO generated a total combined output power of 1.2 W at 3.75 and 4.52 μm under pumping power of 5.3 W, corresponding to slope efficiency of 40% from incident 2-μm laser power to mid-infrared (Mid-IR) output. A widely tunable range from 3.0 to 6.5 μm was achieved by changing the crystal angle only 3.5 .

  8. Characterization of REBa{sub 2}Cu{sub 3}O{sub 7−X} (RE = Gd, Ho) nanostructures, fabricated by a simple technique

    Energy Technology Data Exchange (ETDEWEB)

    Kargar, Mahboubeh [Faculty of Sciences, Najafabad Branch, Islamic Azad University, P.O. Box 517, Najafabad, Esfahan (Iran, Islamic Republic of); Alikhanzadeh-Arani, Sima [Institute of Nano Science and Nano Technology, University of Kashan, P.O. Box 87317-51167, Kashan (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Institute of Nano Science and Nano Technology, University of Kashan, P.O. Box 87317-51167, Kashan (Iran, Islamic Republic of); Bagheri, Samira [Centre for Research in Nanotechnology & Catalysis (NANOCAT), 3rd Floor, Block A, Institute of Postgraduate Studies (IPS), University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2015-04-15

    Highlights: • REBa{sub 2}Cu{sub 3}O{sub 7−X} nanostructures was synthesized by sol–gel method assisted by ultrasonic irradiation. • Different solvents with different vapor pressures were used to achieve different morphologies. • The effect of ultrasound wave was studied on the morphology, particle size and superconducting properties. • Behavior of the magnetic susceptibility of the nanoparticles was studied in different strengths. - Abstract: Simple citrate sol–gel method assisted by ultrasonic irradiation has been employed to fabricate REBa{sub 2}Cu{sub 3}O{sub 7−X} (RE123) (RE = Gd, Ho) nanostructures. The elevated temperature and pressure due to the sudden collapsing the bubbles with a high stability and energy in the ultrasonic procedure gave rise to a clear variation in the morphology, however compared with the bulk samples, the ultrasound waves had no significant effect on the onset critical temperature of the prepared nanoparticles (about 91.4 K). Changes of the magnetic susceptibility with temperature were found to be independent of the applied field strength, probably due to the elimination of the weak links in the products. The influence of various solvents with different vapor pressures and so different destruction powers, including methanol, toluene, 1-butanol, and 1-hexanol, was also studied on the morphology and particle size of the products. The crystalline size of the Ho123 was calculated 32.38 nm, according to the Williamson–Hall plot, in agreement with the TEM images. Using the Rietveld method, the lattice parameters of Ho123 nanoparticles were obtained to be slightly smaller than that of Gd123.

  9. Effect of nano sized oxalate precursor on the formation of REBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (RE= Gd, Sm, Ho) ceramic via coprecipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Hamadneh, Imad; Khalili, Fawwaz [Department of Chemistry, Faculty of Science, University of Jordan, 11942 Amman (Jordan); Shaaer, Mazen [Deanship of Research, University of Jordan, 11942 Amman (Jordan); Rosli, Ahmad Mustaza, E-mail: imad72@hotmail.co [Department of chemistry, Faculty of Science, Universiti Putra Malaysia 43400 Serdang, Selangor (Malaysia)

    2010-06-01

    The formation REBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (RE= Gd, Sm and Ho) superconducting ceramics from metal oxalate precursors with average grain size less than 50 nm using the coprecipitation method is reported. The metal oxalate powders were heated at 900{sup o}C for 12 hours, pelletized and then sintered at 920{sup 0}C for 15 hr. The high-T{sub C} phase was observed for all samples as an evidence for the single step transition of (R-T) curves. The T{sub C(R=0)} for samples Gd123, Ho123 and Sm123 were 95 K, 93 K, 91 K, respectively. XRD data showed single phase of an orthorhombic structure for Sm123 and Ho123 samples, small amount of impurities (Gd211) phase were detected for Gd123. SEM micrographs showed large grain sizes that are randomly distributed. These results showed that COP method using nano sized metal oxalates starting powders is very effective to synthesize high quality superconductors and shorten the sintering time required. The formation Gd211 phase for the Gd123 sample might act as a pinning centre explaining the enhancement of the transport properties.

  10. The magnetic phase transition and the low-field Arrott plots of (GD{sub x}Dy{sub 1-x})Co{sub 2} compounds[75.20.En; 75.30.Kz; (GdxDy1-x)Co2 compounds; First-order transition; Second-order transition; Arrott plots

    Energy Technology Data Exchange (ETDEWEB)

    Wang Dunhui E-mail: wangdh@nju.edu.cn; Tang Shaolong; Huang Songling; Zhang Jianrong; Du Youwei

    2004-01-01

    A series of (Gd{sub x}Dy{sub 1-x})Co{sub 2} (0-0.55) compounds have been prepared by arc-melting method. In order to determine the phase transition order in these compounds, we have performed some magnetization measurements. Only from the plots of temperature dependence of magnetization and the low-field magnetization isotherms, it is difficult to judge the phase transition order. The low-field Arrott plot is proved to be a more reliable method to characterize the first-order transition and the second-order transition. No first-order transition is observed in (Gd{sub x}Dy{sub 1-x})Co{sub 2} compounds (x{ne}0). The result is discussed in the Inoue-Shimizu like model.

  11. Investigation of the transport properties and compositions of the Ca2RE7Pn5O5 series (RE=Pr, Sm, Gd, Dy; Pn=Sb, Bi)

    Science.gov (United States)

    Forbes, Scott; Yuan, Fang; Kosuda, Kosuke; Kolodiazhnyi, Taras; Mozharivskyj, Yurij

    2016-10-01

    The Ca2RE7Pn5O5 phases (RE=Pr, Sm, Gd, Dy; Pn=Sb, Bi) were successfully prepared from high temperature reactions at 1225-1300 °C. These phases maintain the same structure types as the parent RE9Pn5O5 phases, except for a Ca/RE mixing. The study and preparation of these phases was motivated by the desire to shift the metallic type properties of the parent RE9Pn5O5 phases to a level more suitable for thermoelectric applications. Electrical resistivity measurements performed on pure, bulk samples indicated all phases to be narrow band gap semiconductors or semimetals, supporting the charge balanced electron count of the Ca2RE7Pn5O5 composition. Unfortunately, all samples are too electrically resistive for any potential usage as thermoelectrics. Electronic band structure calculations performed on idealized RE9Pn5O5 structures revealed the presence of a pseudogap at the Fermi level, which is consistent with the observed electrical resistivity and Seebeck coefficient behavior.

  12. Structural and optical characterization of NaGdF{sub 4}: Ho{sup 3+}/Yb{sup 3+} UC nano-particles for lateral finger mark detections

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A., E-mail: ak.phy87@gmail.com; Tiwari, S. P.; Krishna, K. M.; Kumar, K. [Optical Materials and Bio-imaging Research Laboratory Department of Applied Physics, Indian School of mines, Dhanbad-826004 (India)

    2016-05-23

    Ho{sup 3+}/Yb{sup 3+} co-doped NaGdF{sub 4} up-conversion (UC) nano-particles were synthesized by thermal decomposition method. X-ray diffraction and FE-SEM image analysis were done to confirm the structure, morphology and determination of particle size. The UC emission spectra for as prepared as well as 100°C, 200°C, 300°C, 400°C, 800°C, 1000°C and 1200°C heated for 3h samples were recorded and there emission intensities were compared at a constant pump power of excitations 98.1 W/cm{sup 2}. The effect of emission intensity on decay time was also studied through focused and unfocused excitations. The synthesized material was successfully utilized in lateral finger mark detections on the glass substrate through powder dusting method.

  13. Magnetic and electrical studies of Ho0.9RE0.1CrO3 (RE = Gd and Yb multiferroics

    Directory of Open Access Journals (Sweden)

    Shubhra Mathur

    2016-09-01

    Full Text Available We report magnetic and electrical studies on multiferroic systems Ho0.9(RE0.1CrO3 where RE symbolizes rare earths like Gd and Yb. Solid state diffusion method has been used to synthesize the samples. Structural phase formation has been confirmed with the help of powder X-ray diffraction. Magnetization measurements show canted antiferromagnetic nature with a weak ferromagnetic phase. Néel temperature for Cr3+–Cr3+ ordering shifts to higher side with increasing radii of rare earth cations. Frequency (100 Hz to 1 MHz and temperature (300–650 K dependent resistivity measurements are suggestive of semiconducting nature of the samples.

  14. Synthesis, characterization, and in vitro evaluation of a radio-metal organic framework composed of in vivo generator {sup 166}Dy/{sup 166}Ho and DOTMP as a novel agent for bone marrow ablation

    Energy Technology Data Exchange (ETDEWEB)

    Vosoghi, Sara; Shirvani-Arani, Simindokht; Bahrami-Samani, Ali; Salek, Nafise; Mirerezaei, Ehsan; Jalilian, Amir Reza [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of)

    2016-07-01

    In this study, the MOF concept contributed to the preparation of a novel, bone-ablating agent composed of Cu(II) using the in vivo generator {sup 166}Dy/{sup 166}Ho and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid (DOTMP). The product was characterized (IR, elemental analysis: CHN, ICM-MS, PIXE, DLS, XRD) and quality-controlled (radio-thin layer chromatography (RTLC)). The stability and in vitro hydroxyapatite binding was checked up to one week at 37 C in human serum. Radio-MOF crystals and colloidal radio-MOF particles were obtained by varying the synthesizing conditions (including pH and temperature), and they had similar IR patterns and similar elemental analysis results. The estimated chemical formula was [1Lu-1Cu-1Cl-1DOTMP] for both. The final product was synthesized at pH = 8 while stirring at room temperature using {sup 166}Dy/{sup 166}Ho-nitrate, CuCl{sub 2}, and DOTMP (yield > 99%, RTLC). Dynamic light scattering (DLS) measurements showed particles in the size range of 60 to 100 nm for the resultant radio-MOF particles (RMP). In vitro binding experiments showed acceptable bone-seeking affinity of the prepared formula even after one week of storage in human serum at 37 C. Importantly, this is the first study of the use of the MOF concept to provide a highly-stable organometallic compound containing {sup 166}Dy/{sup 166}Ho in vivo generator for bone marrow ablation.

  15. Synthesis and Characterization of Ethylthioethylcyclopentadienyl Organolanthanide Complexes:Cp2Th LnCl (Ln=Gd, Dy), Cp2LnCpTh (Ln=Yb, Sm, Dy, Y) and Cp2ThErCl2·2THF

    Institute of Scientific and Technical Information of China (English)

    ZHU Ming朱铭; ZHANG Li-Bei张丽蓓; CHEN Ying-Hua陈应华; ZHOU Xi-Geng周锡庚; CAI Rui-Fang蔡瑞芳; WENG Lin-Hong翁林红

    2004-01-01

    Six new ethylthioethylcyclopentadienyl-containing organolanthanide complexes Cp2Th LnCl [Ln=Gd (1), Dy (2)]and Cp2LnCpTh [Cp=C5H5, Ln=Yb (3), Sm (4), Dy (5), Y (6)] were synthesized by the reaction of ethylthioethylcyclopentadienyl (CpTh) sodium salt with LnC13 or Cp2LnCl in THF. Complexes 1-6 were characterized by elemental analyses, infrared and mass spectroscopies. The molecular structures of complexes 1-3 were also determined by the X-ray single crystal diffraction. The results show that the side-chain sulfur atom on the ethylthioethylcyclopentadienyl ring can form intramolecular chelating coordination to the central lanthanide ion, improving the stability of organolanthanide complexes and reducing the number of coordinated THF molecules.

  16. Optical spectra of Dy3+-doped GdVO4 and Ca3Sc2Ge3O12 crystals and evaluation of the Ω2/Ω6 ratio as a quality factor for the classification of Dy3+-activated crystalline hosts

    Science.gov (United States)

    Cavalli, Enrico

    2016-11-01

    The room temperature absorption spectra of Dy3+-doped GdVO4 and Ca3Sc2Ge3O12 crystals have been measured and analysed in the framework of the Judd-Ofelt Theory. The calculated intensity parameters have then been correlated with the intensities of the emission bands in the yellow and blue region. The analysis has then been extended to a number of host lattices using literature data, and a general empirical model has been proposed, correlating the Ω2/Ω6 and the yellow to blue (Y/B) ratio in order to define a criterion for predicting the visible luminescence properties of the Dy-activated crystalline materials.

  17. Crystal structure, superconductivity and magnetic properties of the superconducting ferromagnets Gd{sub 1.4-x}Dy{sub x}Ce{sub 0.6}Sr{sub 2}RuCu{sub 2}O{sub 10} (x=0-0.6)

    Energy Technology Data Exchange (ETDEWEB)

    Kalavathi, S.; Janaki, J.; Reddy, G.V.R.; Rao, G.V.N.; Sankara Sastry, V.; Hariharan, Y

    2003-07-15

    The structural, electrical and magnetic properties of the superconducting ferromagnets, Gd{sub 1.4-x}Dy{sub x}Ce{sub 0.6}Sr{sub 2}RuCu{sub 2}O{sub 10} (x=0-0.6) are systematically investigated as a function of Dy doping and temperature. These compounds are characterized by high temperature superconductivity (T{sub c} ranging from 20 to 40 K depending upon the Dy content) co-existing with weak ferromagnetism with two magnetic transitions (T{sub M2} ranging from 95 to 106 K and T{sub M1} around 120 K). Doping with Dy gives no significant structural changes except for a minor change in the c/a ratio. However the superconducting transition temperature is significantly suppressed and magnetic ordering temperature enhanced on Dy doping. These effects are described and discussed.

  18. Influence of the substitution of Sm, Gd, and Dy for La in La0.7Sr0.3MnO3 on its magnetic and electric properties and strengthening effect on room-temperature CMR

    Institute of Scientific and Technical Information of China (English)

    SONG Qixiang; WANG Guiying; YAN Guoqing; MAO Qiang; WANG Wenqi; PENG Zhensheng

    2008-01-01

    A series of La0.7-xSmxSr0.3MnO3, La0.7-xGdxSr0.3MnO3, and La0.7-xDyxSr0.3MnO3 (x=0.00, 0.10, 0.20, 0.30) samples were prepared by the solid-state reaction method. The influence of the substitution of Sm, Gd, and Dy for La on the magnetic and electric properties and on the magnetoresistance (MR) was studied through measurements of M-T curves and p-T curves. The results showed that: lattice distortion in-duced by substitution of Sm, Gd, and Dy for La and extra magnetism of substitution had great influence on the magnetic and electric proper-ties of perovskite manganites; substitution of magnetic rare earth element for La was an effective way to change Curie temperature and to strengthen MR in perovskite manganites; and appropriate substitution proportion would generate large MR near room temperature.

  19. Ortho-vanadates K{sub 3}RE(VO{sub 4}){sub 2} (RE = La, Pr, Eu, Gd, Dy, Y) for near UV-converted phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Lin [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Wei, Dong-Lei [Department of Physics and Center for Marine-Integrated Biomedical Technology, Pukyong National University, Busan 608-737 (Korea, Republic of); Huang, Yanlin [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Qin, Chuanxiang, E-mail: qinchuanxiang@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Cai, Peiqing; Kim, Sun-Il [Department of Physics and Center for Marine-Integrated Biomedical Technology, Pukyong National University, Busan 608-737 (Korea, Republic of); Seo, Hyo-Jin, E-mail: hjseo@pknu.ac.kr [Department of Physics and Center for Marine-Integrated Biomedical Technology, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2014-10-15

    The orthovanadate poly-crystals K{sub 3}RE(VO{sub 4}){sub 2} (RE = La, Pr, Eu, Gd, Dy, Y) were synthesized via the solid-state reaction route. The crystal phase formation was verified through X-ray diffraction (XRD) studies and was performed by structural refinements. The optical properties were also investigated in detail. K{sub 3}RE(VO{sub 4}){sub 2} (RE = Eu, Dy, Gd, Pr, La, Y) phosphors present different luminescence behaviors: the profiles of excitation and emission spectra, the spectra shift, the luminescence decay lifetimes, the absolute quantum efficiency (QE), and the CIE color coordinates are very different. The luminescence of K{sub 3}RE(VO{sub 4}){sub 2} (RE = La, Gd, Y, Pr) presents yellow or yellowish green color, while, K{sub 3}Dy(VO{sub 4}){sub 2} and K{sub 3}Eu(VO{sub 4}){sub 2} show white and red luminescence, respectively. This was discussed on the base of the different micro-structure, activator centers, and the charge transfer transitions from [VO{sub 4}]{sup 3−} groups in the lattices. K{sub 3}Y(VO{sub 4}){sub 2} and K{sub 3}Eu(VO{sub 4}){sub 2} show higher QE values of 47.0% and 45.0% at room temperature, respectively. All the phosphors have efficient absorption in the region of near-UV wavelengths or blue wavelength region. This can well match with the light from UV-LED (360–400 nm) or blue LED chips (450–480 nm) based on GaN semiconductor. K{sub 3}RE(VO{sub 4}){sub 2} could be suggested to be a potential candidate to give further investigations for the application on near-UV excited white LEDs. - Graphical abstract: A series of orthovanadates K{sub 3}RE(VO{sub 4}){sub 2} (RE = Eu, Dy, Gd, Pr, La, Y) have been developed to be new phosphors with rich luminescence colors; there are efficiency excitation in the near UV wavelength region. Compared with the reported vanadate phosphors K{sub 3}R(VO{sub 4}){sub 2} has rich luminescence color, rich color, no concentration quenching, and comparable luminescence QE. - Highlights: • A

  20. Infrared and Raman spectra of tris(dipivaloylmethanato) lanthanides, Ln(thd)3 (Ln = La, Nd, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu)

    Science.gov (United States)

    Belova, Natalya V.; Sliznev, Valery V.; Christen, Dines

    2017-03-01

    The infrared and Raman vibrational spectra of the series of solid tris(dipivaloylmethanato) lanthanides, Ln(thd)3 (Ln = La, Nd, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu), have been recorded at room temperature over wide ranges (4000-50 cm-1 and 3500-80 cm-1, respectively). The experimental spectra obtained in the present study were successfully assigned based on the quantum chemical calculations (DFT/PBE0) performed for the monomer Ln(thd)3 molecules. The experimental vibrational spectra for all complexes studied are rather similar as are the theoretical simulations. The data analysis shows that the main contributions to vibrational modes arise from the vibrations of the ligand possessing practically the same geometry for all complexes. According to the calculation results the structure of the coordination polyhedron is increasingly distorted in the series from La(thd)3 to Lu(thd)3. Although the contributions of the polyhedron vibrations in vibrational modes are not predominant, there is rise in the frequencies associated with vibrations of the coordination polyhedron LnO6 in this series. This increase has been explained by the concept of lanthanide contraction.

  1. Separation and Recycling for Rare Earth Elements by Homogeneous Liquid-Liquid Extraction (HoLLE) Using a pH-Responsive Fluorine-Based Surfactant

    OpenAIRE

    2015-01-01

    A selective separation and recycling system for metal ions was developed by homogeneous liquid-liquid extraction (HoLLE) using a fluorosurfactant. Sixty-two different elemental ions (e.g., Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, La, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Re, Rh, Ru, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tl, Tm, V, W, Y, Yb, Zn, and Zr) were examined. By changing pH from a neutral or alkaline solu...

  2. Symmetry-Breaking Transitions in RECuAs2-xPx (RE=Sm, Gd, Ho, and Er)

    Energy Technology Data Exchange (ETDEWEB)

    Mozharivskyj, Yurij [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Structural changes resulting in lower symmetries can be understood in terms of electronic instabilities and Coulomb interactions. The interplay of these two interrelated factors is complicated and difficult to analyze. The RECuAs2-xP x phases, because of the variation in the chemical content (As/P substitution), allow, with the aid of band structures, Madelung energies and Landau theory, a partial unraveling of the forces important in the symmetry-breaking transitions in RECuAs2-xP x (RE = Sm, Gd, Ho and Er). Distortions of the P layers in SmCu1.15P2, GdCuP2.20 and ErCuP2 are usefully thought of as generalized Peierls distortions, i.e., they lower the electronic (and total) energy and lead to more stable structures. On the other hand, the P4/nmm → Pmmn transitions, which are observed in all studied arsenophosphide series and occur upon substitution of P for As, originate from the B1g vibrational mode and are structural adaptations to smaller P atoms. These transitions provide tighter atomic packing and better Coulomb interactions. Configurational contribution to the entropy becomes important in stabilizing the mixed occupancy in the RECuAs 2-xP x arsenophosphides. While geometric and electronic factors favor separation of the As and P atoms over two different crystallographic sites, configurational entropy stabilizes the As/P mixing on these two sites.;Progress in the research on RECuAs2-xP x was dependent upon the ability of Landau theory to predict, explain and dismiss structural models and transitions. The space group Pmmn (arising from the B 1g vibrational mode) in all mixed arsenophosphides and the existence of these mixed arsenophosphides followed from the analysis of GdCuAs 2 and GdCuP2, using Landau theory. The impossibility of obtaining the high-symmetry structure (P4/nmm) and the low symmetry structure

  3. Role of Lanthanide-Ligand bonding in the magnetization relaxation of mononuclear single-ion magnets: A case study on Pyrazole and Carbene ligated LnIII(Ln=Tb, Dy, Ho, Er) complexes

    Indian Academy of Sciences (India)

    TULIKA GUPTA; GUNASEKARAN VELMURUGAN; THAYALAN RAJESHKUMAR; GOPALAN RAJARAMAN

    2016-10-01

    Ab initio CASSCF+RASSI-SO+SINGLE_ANISO and DFT based NBO and QTAIM investigations were carried out on a series of trigonal prismatic M(BcMe)₃ (M = Tb(1), Dy(2), Ho(3), Er(4), [BcMe]⁻ = dihydrobis (methylimidazolyl) borate) and M(BpMe)₃ (M = Tb(1a), Dy(2a), Ho(3a), Er(4a) [BpMe]⁻ = dihydrobis (methypyrazolyl) borate) complexes to ascertain the anisotropic variations of these two ligand field environments and the influence of Lanthanide-ligand bonding on the magnetic anisotropy. Among all the complexes studied, only 1 and 2 show large Ucal (computed energy barrier for magnetization reorientation) values of 256.4 and 268.5 cm⁻¹, respectively and this is in accordance with experiment. Experimentally only frequency dependent χ” tails are observed for complex 1a and our calculation predicts a large Ucalof 229.4 cm⁻¹ for this molecule. Besides these, none of the complexes (3, 4, 2a, 3a and 4a) computed to possess large energy barrier and this is affirmed by the experiments. These observed differences in the magnetic properties are correlated to the Ln-Ligand bonding. Our calculations transpire comparatively improved Single-Ion Magnet (SIM) behaviour for carbene analogues due to the more axially compressed trigonal prismatic ligand environment. Furthermore, our detailed Mulliken charge, spin density, NBO and Wiberg bond analysis implied stronger Ln...H–BH agostic interaction for pyrazole analogues. Further, QTAIM analysis reveals the physical nature of coordination, covalent, and fine details of the agostic interactions in all the eight complexes studied. Quite interestingly, for the first time, using the Laplacian density, we are able to quantify the prolate and oblate nature of the electron clouds in lanthanides and this is expected to have a far reaching outcome beyond the examples studied.

  4. Structural, magnetic and spectral properties of Gd and Dy co-doped dielectrically modified Co-Ni (Ni0.4Co0.6Fe2O4) ferrites

    Science.gov (United States)

    Ditta, Allah; Khan, Muhammad Azhar; Junaid, Muhammad; Khalil, R. M. Arif; Warsi, Muhammad Farooq

    2017-02-01

    Gadolinium (Gd) and Dysprosium (Dy) co-doped Ni-Co (Ni0.4Co0.6Fe2O4) ferrites were prepared by micro-emulsion route. X-ray diffraction (XRD) analysis indicated the development of cubic spinel structure. The lattice parameter and X-ray density were found to increase from 8.24 to 8.31 Å and 5.57 to 5.91 (gm/cm3) respectively as the Gd-Dy contents increased in nickel-cobalt ferrites. The crystallite size calculated from the Scherrer's formula exhibited the formation of nanocrystalline ferrites (13-26 nm). Two foremost absorption bands observed in FTIR spectra within 400 cm-1 (υ2) to 600 cm-1 (υ1) which correspond to stretching vibrations of tetrahedral and octahedral complexes respectively. The dielectric constant (ε) and dielectric loss (tanδ) were decreased by the optimization of frequency and abrupt decrease in the low frequency region and higher values in the high frequency region were observed. The dielectric dispersion was due to rapid decrease of dielectric constant in the low frequency region. This variation of dielectric dispersion was explicated in the light of space charge polarization model of Maxwell-Wagner. The dielectric loss occurs in these ferrites due to electron hopping and defects in the dipoles. The electron hopping was possible at low frequency range but at higher frequency the dielectric loss was decreased with the decrease of electron hopping. Magnetic properties were observed by measuring M-H loops. Due to low dielectric loss and dielectric constant these materials were appropriate in the fabrication of switching and memory storage devices.

  5. Structural, magnetic and spectral properties of Gd and Dy co-doped dielectrically modified Co-Ni (Ni{sub 0.4}Co{sub 0.6}Fe{sub 2}O{sub 4}) ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Ditta, Allah [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Khan, Muhammad Azhar, E-mail: azhar.khan@iub.edu.pk [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Junaid, Muhammad, E-mail: junaid.malik95@yahoo.com [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Khalil, R.M. Arif [Department of Physics, Sahiwal Sub-Campus Bahauddin Zakariya University, Sahiwal (Pakistan); Warsi, Muhammad Farooq [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

    2017-02-15

    Gadolinium (Gd) and Dysprosium (Dy) co-doped Ni-Co (Ni{sub 0.4}Co{sub 0.6}Fe{sub 2}O{sub 4}) ferrites were prepared by micro-emulsion route. X-ray diffraction (XRD) analysis indicated the development of cubic spinel structure. The lattice parameter and X-ray density were found to increase from 8.24 to 8.31 Å and 5.57 to 5.91 (gm/cm{sup 3}) respectively as the Gd-Dy contents increased in nickel-cobalt ferrites. The crystallite size calculated from the Scherrer's formula exhibited the formation of nanocrystalline ferrites (13–26 nm). Two foremost absorption bands observed in FTIR spectra within 400 cm{sup −1} (υ{sub 2}) to 600 cm{sup −1} (υ{sub 1}) which correspond to stretching vibrations of tetrahedral and octahedral complexes respectively. The dielectric constant (ε) and dielectric loss (tanδ) were decreased by the optimization of frequency and abrupt decrease in the low frequency region and higher values in the high frequency region were observed. The dielectric dispersion was due to rapid decrease of dielectric constant in the low frequency region. This variation of dielectric dispersion was explicated in the light of space charge polarization model of Maxwell-Wagner. The dielectric loss occurs in these ferrites due to electron hopping and defects in the dipoles. The electron hopping was possible at low frequency range but at higher frequency the dielectric loss was decreased with the decrease of electron hopping. Magnetic properties were observed by measuring M-H loops. Due to low dielectric loss and dielectric constant these materials were appropriate in the fabrication of switching and memory storage devices.

  6. Planar tetranuclear Dy(III) single-molecule magnet and its Sm(III), Gd(III), and Tb(III) analogues encapsulated by salen-type and β-diketonate ligands.

    Science.gov (United States)

    Yan, Peng-Fei; Lin, Po-Heng; Habib, Fatemah; Aharen, Tomoko; Murugesu, Muralee; Deng, Zhao-Peng; Li, Guang-Ming; Sun, Wen-Bin

    2011-08-01

    The syntheses, structures, and magnetic properties are reported for four new lanthanide clusters [Sm(4)(μ(3)-OH)(2)L(2)(acac)(6)]·4H(2)O (1), [Gd(4)(μ(3)-OH)(2)L(2)(acac)(6)]·4CH(3)CN (2), and [Ln(4)(μ(3)-OH)(2)L(2)(acac)(6)]·2H(2)L·2CH(3)CN (3, Ln = Tb; 4, Ln = Dy) supported by salen-type (H(2)L = N,N'-bis(salicylidene)-1,2-cyclohexanediamine) and β-diketonate (acac = acetylacetonate) ligands. The four clusters were confirmed to be essentially isomorphous by infrared spectroscopy and single-crystal X-ray diffraction. Their crystal structures reveal that the salen-type ligand provides a suitable tetradentate coordination pocket (N(2)O(2)) to encapsulate lanthanide(III) ions. Moreover, the planar Ln(4) core is bridged by two μ(3)-hydroxide, four phenoxide, and two ketonate oxygen atoms. Magnetic properties of all four compounds have been investigated using dc and ac susceptibility measurements. For 4, the static and dynamic data indicate that the Dy(4) complex exhibits slow relaxation of the magnetization below 5 K associated with single-molecule magnet behavior.

  7. Metathesis synthesis, characterization, spectral and photoactivity studies of Ln2/3MoO4 (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er and Y)

    Institute of Scientific and Technical Information of China (English)

    Radha Velchuri; Suresh Palla; G. Ravi; Naveen Kumar Veldurthi; J.R. Reddy; M. Vithal

    2015-01-01

    Rare earth ortho-oxomolybdates of composition Ln2/3MoO4 (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er and Y) were prepared by metathesis reaction. All these materials were characterized by powder X-ray diffraction, Fourier transform-infrared spectroscopy (FT-IR) and UV-Vis diffuse reflectance spectra. The Rietveld analysis of all the samples was carried out to obtain the unit cell pa-rameters and reliability factors. All the materials were crystallized in tetragonal lattice withI41/a space group. The infrared spectra of all the samples were characterized by bands due to MoO42– units. The bandgap energies of all the samples were obtained from UV-Vis DRS spectra. The luminescence spectra of Ln2/3MoO4 (Ln=Pr, Eu and Dy) showed characteristic transitions of the rare earth ions. The visible light photocatalytic activity of all the samples was studied against degradation of methylene blue.

  8. Heterometallic octanuclear RE(III)3Ni(II)5 (RE = Dy(III), Gd(III) and Y(III)) clusters with slow magnetic relaxation for the dysprosium derivative.

    Science.gov (United States)

    Wang, Huiyu; Ke, Hongshan; Lin, Shuang-Yan; Guo, Yang; Zhao, Lang; Tang, Jinkui; Li, Yun-Hui

    2013-04-21

    Reactions of rare earth benzoate and nickel perchlorate with a Schiff-base ligand, 2-([(2-hydroxyphenyl)imino]methyl) phenol (H2L), in the presence of triethylamine yielded three heterobimetallic octanuclear clusters of general formula [RE3Ni5L5(PhCOO)3(μ3-OH)5(μ3-OCH3)(CH3OH)4(H2O)]·xCH3OH·yH2O (RE = Dy(III), x = 4, y = 4 (1), RE = Gd(III), x = 5, y = 4 (2), RE = Y(III), x = 5, y = 3 (3)). Single-crystal X-ray diffraction reveals that the metal core of each cluster consists of two distorted [RE2Ni2O4] cubane-like moieties and a heterobimetallic triangular [RE2NiO2] unit, with RE ions arranged in a typical triangular fashion. Variable-temperature solid state magnetic susceptibilities of these complexes were measured in the temperature range 2-300 K and the results indicate that an overall ferromagnetic interaction among the metal ions is operative for compounds 2 and 3. Under zero external field, the Dy3Ni5 compound shows a frequency dependence of the out-of-phase (χ'') signals, which indicates slow relaxation of the magnetization.

  9. Crystallographic and magnetic properties of R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy)

    CERN Document Server

    Han Xiu Feng; Li Qi; Zhang Mao Cai; Zhou Shou Zeng

    1998-01-01

    A systematic investigation of crystallographic and magnetic properties of nitride R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy) has been performed. Nitrogenation leads to a relative volume expansion of about 6%. The lattice constants and unit cell volume decrease with increasing rare-earth atomic number from Nd to Dy, reflecting the lanthanide contraction. On average, the Curie temperature increases due to the nitrogenation to about 200 K compared with its parent compound. Generally speaking, nitrogenation also results in a remarkable improvement of the saturation magnetization and anisotropy fields at 4.2 K and room temperature for R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 compared with their parent compounds. The transition temperature indicates the spin reorientations of R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 for R Nd and Sm are at around 375 and 370 K which are higher than that of R sub 3 Fe sub 2 sub 9 sub - sub x V sub x for R = Nd and Sm 145...

  10. A binuclear Fe(III)Dy(III) single molecule magnet. Quantum effects and models.

    Science.gov (United States)

    Ferbinteanu, Marilena; Kajiwara, Takashi; Choi, Kwang-Yong; Nojiri, Hiroyuki; Nakamoto, Akio; Kojima, Norimichi; Cimpoesu, Fanica; Fujimura, Yuichi; Takaishi, Shinya; Yamashita, Masahiro

    2006-07-19

    The binuclear [FeIII(bpca)(mu-bpca)Dy(NO3)4], having Single Molecule Magnet (SMM) properties, belonging to a series of isostructural FeIIILnIII complexes (Ln = Eu, Gd, Tb, Dy, Ho) and closely related FeIILnIII chain structures, was characterized in concise experimental and theoretical respects. The low temperature magnetization data showed hysteresis and tunneling. The anomalous temperature dependence of Mössbauer spectra is related to the onset of magnetic order, consistent with the magnetization relaxation time scale resulting from AC susceptibility measurements. The advanced ab initio calculations (CASSCF and spin-orbit) revealed the interplay of ligand field, spin-orbit, and exchange effects and probed the effective Ising nature of the lowest states, involved in the SMM and tunneling effects.

  11. Features of magnetic and thermal properties of R(Co{sub 1−x}Fe{sub x}){sub 2} (x≤0.16) quasibinary compounds with R=Dy, Ho, Er

    Energy Technology Data Exchange (ETDEWEB)

    Anikin, Maksim; Tarasov, Evgeniy; Kudrevatykh, Nikolay [Institute of Natural Sciences, Ural Federal University, Ekaterinburg 620002 (Russian Federation); Inishev, Aleksander [Institute of Metal Physics, Ekaterinburg 620137 (Russian Federation); Semkin, Mikhail; Volegov, Aleksey; Zinin, Aleksander [Institute of Natural Sciences, Ural Federal University, Ekaterinburg 620002 (Russian Federation)

    2016-11-15

    In this work the results of measurements of high field susceptibility, paraprocess susceptibility and thermal properties of R(Co{sub 1−x}Fe{sub x}){sub 2} intermetallic compounds (R=Dy, Ho, Er and x=(0−0.16)) are presented (heat capacity and magnetocaloric effect (MCE)). A magnetic structure of the Ho(Co{sub 0.88}Fe{sub 0.12}){sub 2} at 293 K and 78 K was studied by neutron powder diffraction. Some peculiarities of a high-field susceptibility were revealed at low temperatures and around the Curie point (T{sub C}). In temperature range lower than T{sub C} by (100–150) K, magnetic contributions to a zero-field heat capacity were found. Studying MCE in wide temperatures range, the large change of the entropy magnetic contribution (∆S) was observed which correlates with ∆T phenomenon. In particular, for the Er(Co{sub 0.84}Fe{sub 0.16}){sub 2} compound the ∆S value at low temperatures is six times higher than that at Curie point. The possible reasons of such behavior were discussed. - Highlights: • Magnetic and magnetocaloric properties of R(Co–Fe){sub 2} compounds have been studied. • Fe introduction induces the disorientation effect in Ho-ions magnetic ordering. • Emergence of magnetic contribution to a heat capacity at temperatures less T{sub C}. • The existence of a broad maximum on a temperature dependence of the MCE. • Direct MCE measurements at magnetic field of (0–17.5) kOe have been performed.

  12. New orthorhombic derivative of CaCu{sub 5}-type structure: RNi{sub 4}Si compounds (R=Y, La, Ce, Sm, Gd–Ho), crystal structure and some magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Morozkin, A.V., E-mail: morozkin@general.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India)

    2013-12-15

    The crystal structure of new YNi{sub 4}Si-type RNi{sub 4}Si (R=Y, La, Ce, Sm, Gd–Ho) compounds has been established using powder X-ray diffraction. The YNi{sub 4}Si structure is a new structure type, which is orthorhombic derivative of CaCu{sub 5}-type structure (space group Cmmm N 65, oC12). GdNi{sub 4}Si and DyNi{sub 4}Si compounds order ferromagnetically at 25 and 19 K, respectively whereas YNi{sub 4}Si shows antiferromagnetic nature. At 15 K, DyNi{sub 4}Si shows second antiferromagnetic-like transition. The magnetic moment of GdNi{sub 4}Si at 5 K in 50 kOe field is ∼7.2 μ{sub B}/f.u. suggesting a completely ordered ferromagnetic state. The magnetocaloric effect of GdNi{sub 4}Si is calculated in terms of isothermal magnetic entropy change and it reaches the maximum value of −12.8 J/kg K for a field change of 50 kOe near T{sub C} ∼25 K. - Graphical abstract: The RNi{sub 4}Si (R=Y, La, Ce, Sm, Gd–Ho) compounds crystallize in new YNi{sub 4}Si-type structure which is orthorhombic derivative of the basic CaCu{sub 5}-type structure. GdNi{sub 4}Si and DyNi{sub 4}Si compounds show the ferromagnetic-like ordering, whereas.YNi{sub 4}Si has the antiferromagnetic nature. The GdNi{sub 4}Si demonstrates the big magnetocaloric effect near temperature of ferromagnetic ordering. The relationship between initial CaCu{sub 5}-type DyNi{sub 5} and YNi{sub 4}Si-type DyNi{sub 4}Si lattices.

  13. Peculiarity of component interaction in {l_brace}Y, Dy{r_brace}-Mn-Sn ternary systems

    Energy Technology Data Exchange (ETDEWEB)

    Romaka, V.V. [Department of Materials Engineering and Applied Physics, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Konyk, M. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Romaka, L., E-mail: romakal@franko.lviv.ua [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Pavlyuk, V. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Jan Dlugosz University, Institute of Chemistry, Environmental Protection and Biotechnology, al. Armii Krajowej 13/15, 42200 Czestochowa (Poland); Ehrenberg, H. [Institute for Complex Materials, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden (Germany); Tkachuk, A. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine)

    2011-07-14

    Highlights: > {l_brace}Y, Dy{r_brace}-Mn-Sn ternary systems at 770 K are characterized by formation of stannides with general compositions RMn{sub 6}Sn{sub 6} and R{sub 4}Mn{sub 4}Sn{sub 7}. > The crystal structure of YMn{sub 6}Sn{sub 6} was determined by single crystal and powder diffraction methods. > Structural analysis showed that Dy{sub 4}Mn{sub 4}Sn{sub 7} compound is disordered. > Isostructural R{sub 4}Mn{sub 4}Sn{sub 7} compounds were also found with Gd, Tb, Ho, Er, Tm(confirmed), Yb, and Lu. - Abstract: The phase equilibria in the Y-Mn-Sn and Dy-Mn-Sn ternary systems were studied at 770 K by means of X-ray and metallographic analyses in the whole concentration range. Both Y-Mn-Sn and Dy-Mn-Sn systems are characterized by formation of two ternary compounds RMn{sub 6}Sn{sub 6} (MgFe{sub 6}Ge{sub 6}-type, space group P6/mmm) and R{sub 4}Mn{sub 4}Sn{sub 7} (Zr{sub 4}Co{sub 4}Ge{sub 7}-type, space group I4/mmm). The disorder in Dy{sub 4}Mn{sub 4}Sn{sub 7} compound was found by single crystal method. Compounds with the same type of structure were also found with Gd, Tb, Ho, Er, Tm (confirmed), Yb, and Lu and their lattice parameters were determined.

  14. Charge transfer excitation of trivalent rare earth ions Sm/sup 3+/, Eu/sup 3+/, Gd/sup 3+/, Ho/sup 3+/, Er/sup 3+/ and Yb/sup 3+/ emission in BaFCl crystals

    Energy Technology Data Exchange (ETDEWEB)

    Su, M.Z.; Sun, X.P.

    1987-01-01

    The charge transfer type excitation spectra of trivalent rare earth ions Sm/sup 3+/, Eu/sup 3+/, Gd/sup 3+/, Ho/sup 3+/, Er/sup 3+/ and Yb/sup 3+/ emission in BaFCl crystals have been studied. The charge transfer type emissions of Ho/sup 3+/, Er/sup 3+/ and Yb/sup 3+/ in BaFCl have also been observed in addition to that of Eu/sup 3+/. The energy of charge transfer band of these RE/sup 3+/ ions were estimated experimentally and also calculated by Jorgensen's refined electron spin-pairing energy theory. Both the experimental and calculated values coincide well.

  15. Anisotropic superconducting and normal state magnetic properties of single crystals of RNi*2*B*2*C compounds (R = Y, Gd, Dy, Ho, Er, and Tm)

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Beongki [Iowa State Univ., Ames, IA (United States)

    1995-09-26

    The interaction of superconductivity with magnetism has been one of the most interesting and important phenomena in solid state physics since the 1950`s when small amounts of magnetic impurities were incorporated in superconductors. The discovery of the magnetic superconductors RNi2B2C (R = rare earth, Y) offers a new system to study this interaction. The wide ranges of superconducting transition (Tc) and antiferromagnetic (AF) ordering temperatures (TN) (0 K ≤ Tc ≤ 16 K, 0 K ≤ TN ≤ 20 K) give a good opportunity to observe a variety of interesting phenomena. Single crystals of high quality with appropriate size and mass are crucial in examining the anisotropic intrinsic properties. Single crystals have been grown successfully by an unusual high temperature flux method and characterized thoroughly by X-ray, electrical transport, magnetization, neutron scattering, scanning electron microscopy, and other measurements.

  16. The magnetic properties and magnetocaloric effects in binary R–T (R = Pr, Gd, Tb, Dy, Ho, Er, Tm; T = Ga, Ni, Co, Cu) intermetallic compounds

    Science.gov (United States)

    Zheng, Xin-Qi; Shen, Bao-Gen

    2017-02-01

    Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 11274357, 51501005, 51590880, and 11674008), the Fundamental Research Funds for the Central Universities, China (Grant No. FRF-TP-15-010A1), the China Postdoctoral Science Foundation (Grant No. 2016M591071), and the Key Research Program of the Chinese Academy of Sciences (Grant No. KJZD-EW-M05).

  17. The high-temperature modification of LuAgSn and high-pressure high-temperature experiments on DyAgSn, HoAgSn, and YbAgSn

    Energy Technology Data Exchange (ETDEWEB)

    Heying, B.; Rodewald, U.C.; Hermes, W.; Schappacher, F.M.; Riecken, J.F.; Poettgen, R. [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Heymann, G.; Huppertz, H. [Muenchen Univ. (Germany). Dept. fuer Chemie und Biochemie; Sebastian, C.P. [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

    2008-02-15

    The high-temperature modification of LuAgSn was obtained by arc-melting an equiatomic mixture of the elements followed by quenching the melt on a water-cooled copper crucible. HT-LuAgSn crystallizes with the NdPtSb-type structure, space group P6{sub 3}mc: a = 463.5(1), c = 723.2(1) pm, wR2 = 0.0270, 151 F{sup 2}, and 11 variables. The silver and tin atoms build up two-dimensional, puckered [Ag{sub 3}Sn{sub 3}] networks (276 pm Ag-Sn) that are charge-balanced and separated by the lutetium atoms. The Ag-Sn distances between the [Ag{sub 3}Sn{sub 3}] layers of 294 pm are much longer. Single crystals of isotypic DyAgSn (a = 468.3(1), c = 734.4(1) pm, wR2 = 0.0343, 411 F{sup 2}, and 11 variables) and HoAgSn (a = 467.2(1), c = 731.7(2) pm, wR2 = 0.0318, 330 F{sup 2}, and 11 variables) were obtained from arc-melted samples. Under high-pressure (up to 12.2 GPa) and high-temperature (up to 1470 K) conditions, no transitions to a ZrNiAl-related phase have been observed for DyAgSn, HoAgSn, and YbAgSn. HT-TmAgSn shows Curie-Weiss paramagnetism with {mu}{sub eff} = 7.53(1) {mu}{sub B}/Tm atom and {theta}P = -15.0(5) K. No magnetic ordering was evident down to 3 K. HT-LuAgSn is a Pauli paramagnet. Room-temperature {sup 119}Sn Moessbauer spectra of HT-TmAgSn and HT-LuAgSn show singlet resonances with isomer shifts of 1.78(1) and 1.72(1) mm/s, respectively. (orig.)

  18. Tunable upconversion luminescence from the phosphors of Yb{sup 3+}, Tm{sup 3+} and Ho{sup 3+} tri-doped Re{sub 2}TeO{sub 6} (Re = La, Gd, and Lu)

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jianfeng, E-mail: tangjf@swu.edu.cn; Gou, Jie; Li, Guannan; He, Hong; Li, Yuan; Li, Chunmei

    2016-07-05

    Phosphors of Re{sub 2}TeO{sub 6} (Re = La, Gd, and Lu) tri-doped with Yb{sup 3+}, Tm{sup 3+} and Ho{sup 3+} ions have been synthesized by the solid state reactions. The crystal structures have been characterized by powder XRD measurement. The SEM images have shown the average particle sizes of the phosphors can be controlled within 1 micron. Upconversion luminescences were investigated under the excitation of 976 nm laser diode. The upconversion processes were explained based on the pump dependence of upconversion emission intensity. The light color was studied in the framework of 1931 CIE diagram. The three systems have shown nice tunabilities by changing the pump intensity and rare earth ions concentration. By properly adjusting the concentration of Tm{sup 3+} ions white upconversion luminescence can be realized in all the three tri-doped systems. Results indicated that these phosphors have potential applications in the upconversion based white lighting and optoelectronic devices. - Highlights: • Upconversions of Re{sub 2}TeO{sub 6} (Re = La, Gd, and Lu) tri-doped with Yb{sup 3+}, Tm{sup 3+}, and Ho{sup 3+} were investigated. • The light colors can be well tuned in the white region via adjusting the pump power and Tm{sup 3+} concentration. • The phosphors are potentials for white lighting and optoelectronic devices.

  19. 94 β -Decay Half-Lives of Neutron-Rich Cs 55 to Ho 67 : Experimental Feedback and Evaluation of the r -Process Rare-Earth Peak Formation

    Science.gov (United States)

    Wu, J.; Nishimura, S.; Lorusso, G.; Möller, P.; Ideguchi, E.; Regan, P.-H.; Simpson, G. S.; Söderström, P.-A.; Walker, P. M.; Watanabe, H.; Xu, Z. Y.; Baba, H.; Browne, F.; Daido, R.; Doornenbal, P.; Fang, Y. F.; Gey, G.; Isobe, T.; Lee, P. S.; Liu, J. J.; Li, Z.; Korkulu, Z.; Patel, Z.; Phong, V.; Rice, S.; Sakurai, H.; Sinclair, L.; Sumikama, T.; Tanaka, M.; Yagi, A.; Ye, Y. L.; Yokoyama, R.; Zhang, G. X.; Alharbi, T.; Aoi, N.; Bello Garrote, F. L.; Benzoni, G.; Bruce, A. M.; Carroll, R. J.; Chae, K. Y.; Dombradi, Z.; Estrade, A.; Gottardo, A.; Griffin, C. J.; Kanaoka, H.; Kojouharov, I.; Kondev, F. G.; Kubono, S.; Kurz, N.; Kuti, I.; Lalkovski, S.; Lane, G. J.; Lee, E. J.; Lokotko, T.; Lotay, G.; Moon, C.-B.; Nishibata, H.; Nishizuka, I.; Nita, C. R.; Odahara, A.; Podolyák, Zs.; Roberts, O. J.; Schaffner, H.; Shand, C.; Taprogge, J.; Terashima, S.; Vajta, Z.; Yoshida, S.

    2017-02-01

    The β -decay half-lives of 94 neutron-rich nuclei Cs-151144 , Ba-154146 , La-156148 , Ce-158150 , Pr-160153 , Nd-162156 , Pm-163159 , Sm-166160 , Eu-168161 , Gd-170165 , Tb-172166 , Dy-173169 , Ho-175172 , and two isomeric states Erm174 , Dym172 were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of β -decay half-lives are observed at neutron-number N =97 for Ce 58 , Pr 59 , Nd 60 , and Sm 62 , and N =105 for Eu 63 , Gd 64 , Tb 65 , and Dy 66 . Features in the data mirror the interplay between pairing effects and microscopic structure. r -process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.

  20. Trends in Syntheses, Structures, and Properties for Three Series of Ammine Rare-Earth Metal Borohydrides, M(BH4)3·nNH3 (M = Y, Gd, and Dy).

    Science.gov (United States)

    Jepsen, Lars H; Ley, Morten B; Černý, Radovan; Lee, Young-Su; Cho, Young Whan; Ravnsbæk, Dorthe; Besenbacher, Flemming; Skibsted, Jørgen; Jensen, Torben R

    2015-08-03

    Fourteen solvent- and halide-free ammine rare-earth metal borohydrides M(BH4)3·nNH3, M = Y, Gd, Dy, n = 7, 6, 5, 4, 2, and 1, have been synthesized by a new approach, and their structures as well as chemical and physical properties are characterized. Extensive series of coordination complexes with systematic variation in the number of ligands are presented, as prepared by combined mechanochemistry, solvent-based methods, solid-gas reactions, and thermal treatment. This new synthesis approach may have a significant impact within inorganic coordination chemistry. Halide-free metal borohydrides have been synthesized by solvent-based metathesis reactions of LiBH4 and MCl3 (3:1), followed by reactions of M(BH4)3 with an excess of NH3 gas, yielding M(BH4)3·7NH3 (M = Y, Gd, and Dy). Crystal structure models for M(BH4)3·nNH3 are derived from a combination of powder X-ray diffraction (PXD), (11)B magic-angle spinning NMR, and density functional theory (DFT) calculations. The structures vary from two-dimensional layers (n = 1), one-dimensional chains (n = 2), molecular compounds (n = 4 and 5), to contain complex ions (n = 6 and 7). NH3 coordinates to the metal in all compounds, while BH4(-) has a flexible coordination, i.e., either as a terminal or bridging ligand or as a counterion. M(BH4)3·7NH3 releases ammonia stepwise by thermal treatment producing M(BH4)3·nNH3 (6, 5, and 4), whereas hydrogen is released for n ≤ 4. Detailed analysis of the dihydrogen bonds reveals new insight about the hydrogen elimination mechanism, which contradicts current hypotheses. Overall, the present work provides new general knowledge toward rational materials design and preparation along with limitations of PXD and DFT for analysis of structures with a significant degree of dynamics in the structures.

  1. Amending the anisotropy barrier and luminescence behavior of heterometallic trinuclear linear [M(II) -Ln(III) -M(II) ] (Ln(III) =Gd, Tb, Dy; M(II) =Mg/Zn) complexes by change from divalent paramagnetic to diamagnetic metal ions.

    Science.gov (United States)

    Das, Sourav; Bejoymohandas, K S; Dey, Atanu; Biswas, Sourav; Reddy, M L P; Morales, Roser; Ruiz, Eliseo; Titos-Padilla, Silvia; Colacio, Enrique; Chandrasekhar, Vadapalli

    2015-04-20

    The sequential reaction of a multisite coordinating compartmental ligand [2-(2-hydroxy-3-(hydroxymethyl)-5-methylbenzylideneamino)-2-methylpropane-1,3-diol] (LH4 ) with appropriate lanthanide salts followed by the addition of [Mg(NO3 )2 ]⋅6 H2 O or [Zn(NO3 )2 ]⋅6 H2 O in a 4:1:2 stoichiometric ratio in the presence of triethylamine affords a series of isostructural heterometallic trinuclear complexes containing [Mg2 Ln](3+) (Ln=Dy, Gd, and Tb) and [Zn2 Ln](3+) (Ln=Dy, Gd, and Tb) cores. The formation of these complexes is demonstrated by X-ray crystallography as well as ESI-MS spectra. All complexes are isostructural possessing a linear trimetallic core with a central lanthanide ion. The comprehensive studies discussed involve the synthesis, structure, magnetism, and photophysical properties on this family of trinuclear [Mg2 Ln](3+) and [Zn2 Ln](3+) heterometallic complexes. [Mg2 Dy](3+) and [Zn2 Dy](3+) show slow relaxation of the magnetization below 12 K under zero applied direct current (dc) field, but without reaching a neat maximum, which is due to the overlapping with a faster quantum tunneling relaxation mediated through dipole-dipole and hyperfine interactions. Under a small applied dc field of 1000 Oe, the quantum tunneling is almost suppressed and temperature and frequency dependent peaks are observed, thus confirming the single-molecule magnet behavior of complexes [Mg2 Dy](3+) and [Zn2 Dy](3+) .

  2. Crystal structure, magnetic and electrical properties of compounds in the RCrMnO{sub 5} family (R = Sm, Eu, Gd, Tb, Ho and Er) synthesized under high oxygen pressure

    Energy Technology Data Exchange (ETDEWEB)

    Pomiro, Fernando; Miner, Elisa V.P.; Carbonio, Raul E. [INFIQC (CONICET - Universidad Nacional de Cordoba), Departamento de Fisicoquimica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba (Argentina); Lohr, Javier; Sanchez, Rodolfo D. [Centro Atomico Bariloche, Comision Nacional de Energia Atomica and Instituto Balseiro, Universidad Nacional de Cuyo, San Carlos de Bariloche (Argentina); Nassif, Vivian [Institut Neel, CNRS et Universite Joseph Fourier, Grenoble (France)

    2015-10-15

    RCrMnO{sub 5} (R = Sm, Eu, Gd, Tb, Ho, and Er) were synthesized at high O{sub 2} pressures and 900-950 C. Crystal structures were refined by using powder X-ray diffraction (PXRD) and powder neutron diffraction (PND) for Tb, Ho, and Er compounds and PXRD for Sm, Eu and Gd compounds. All compounds were isostructural with RMn{sub 2}O{sub 5}. By using the bond-valence model we found that (Cr/Mn){sup 4+} mainly occupy the octahedral sites and (Cr/Mn){sup 3+} occupy the pyramidal sites. Antisite disorder between octahedral and pyramidal sites was found in the three samples analyzed by PND. From the values obtained for the occupancies of Cr and Mn in the pyramidal and octahedral sites and from the approximate average oxidation states for each crystallographic site obtained by the bond-valence calculations, an estimated ionic distribution model was proposed. The μ{sub eff} value for RCrMnO{sub 5} could be explained by considering the contribution of all the paramagnetic species and by using the ionic distribution model. No magnetic long-range order was observed by PND in R = Er, Ho, and Tb compounds. All the Curie-Weiss temperatures obtained from the magnetic susceptibility were negative (θ < 0), indicating antiferromagnetic correlations. For the compounds with Eu and Sm, θ close to -200 K were obtained for the Cr-Mn sublattice. The semiconducting properties could be described by a variable range hopping mechanism associated with antisite disorder of Cr/Mn. No dielectric transitions were observed in the electric permittivity in the measured temperature range. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Investigation of spectroscopic properties and energy transfer between Ce and Dy in (Lu{sub 0.2}Gd{sub 0.8−x−y}Ce{sub x}Dy{sub y}){sub 2}SiO{sub 5} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Strzęp, A. [Institute of Low Temperature and Structure Research PAS, Wroclaw (Poland); Martin, I.R. [Faculty of Physics, Universidad de La Laguna, S/C de Tenerife (Spain); Malta Consolider Team and Instituto de Materiales y Nanotecnología (IMN), Universidad de La Laguna, S/C de Tenerife (Spain); Głowacki, M. [Institute of Physics PAS, Warsaw (Poland); Ryba-Romanowski, W. [Institute of Low Temperature and Structure Research PAS, Wroclaw (Poland); Berkowski, M. [Institute of Physics PAS, Warsaw (Poland); Pérez-Rodríguez, C. [Faculty of Physics, Universidad de La Laguna, S/C de Tenerife (Spain); Malta Consolider Team and Instituto de Materiales y Nanotecnología (IMN), Universidad de La Laguna, S/C de Tenerife (Spain)

    2015-10-15

    In this paper we present results of spectroscopic investigations of single crystals with general formula (Lu{sub 0.2}Gd{sub 0.8−x−y}){sub 2}SiO{sub 5} codoped with x% of Ce{sup {sub 3}{sub +}} and y% of Dy{sup {sub 3}{sub +}} ions. Investigated materials exhibit strong optical anisotropy what can be easily observed in polarized absorption and emission spectra. Based on room temperature polarized absorption spectra calculations in framework of phenomenological Judd–Ofelt model was carried out. Intensity parameters Ω{sub t} were evaluated to be Ω{sub 2}=7.08 (±0.39), Ω{sub 4}=2.76 (±0.44), and Ω{sub 6}=3.36 (±0.21) [10{sup −20} cm{sup 2}] for sample doped with 1% of cerium and Ω{sub 2}=10.72 (±0.33), Ω{sub 4}=1.98 (±0.37), and Ω{sub 6}=2.11 (±0.18) [10{sup −20} cm{sup 2}] for sample doped with 3% of cerium. Influence of cerium admixture on Judd Ofelt intensity parameters is discussed. Value of experimental lifetime of {sub 4}F{sub 9/2} multiplet of Dy{sup 3+} ion in sample doped with 1 at% Ce is 0.5 ms (τ{sub rad}=0.45 ms), while for sample doped with 3 at% of Ce, experimental lifetime is 0.45 ms (τ{sub rad}=0.43 ms). Absorption bands located between 440 and 460 nm, can be utilized for optical pumping of material by GaN laser diodes. Intense and broad emission bands at 465–495 and 560–590 nm, with experimental branching ratio strongly depending on polarization, give high chance for obtaining white luminophore, due to appropiate mixing of blue and yellow luminescence. By means of a pump and probe experiment optical amplification was demonstrated in the codoped sample with 1 at% of Ce and 1 at% Dy at 575 nm corresponding to the emission of Dy{sup 3+} with a high net gain coefficient of 34 cm{sup −1}. Such high amplification was obtained under 359 nm excitation (at the maximum of intense absorption band of Ce{sup 3+} ions). - Highlights: • Influence of anisotropy on properties of LGSO: Ce, Dy crystals was investigated. • ET between Ce

  4. Solid-state synthesis and lanthanide photoluminescence of doped yttrium molybdo-antimonites, Y{sub 2−n}A{sub n}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er; n=0.02–2) solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mohitkar, Shrikant A.; Vidyasagar, K., E-mail: kvsagar@iitm.ac.in

    2015-05-15

    Abstract:: Y{sub 2−n}A{sub n}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er; n=0.02–2) solid solutions were synthesized by a solid-state method and studied for their lanthanide photoluminescence. They show concentration dependent lanthanide photoluminescence and existence of concentration quenching phenomenon. The emission intensity and the fluorescence-lifetime are found to be highest for an optimum concentration of a given lanthanide ion in the solid solution series studied. The neat photoluminescence of A{sub 2}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er) compounds involves partial concentration quenching. - Highlights: • Isostructural Y{sub 2−n}A{sub n}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er; n=0.02–2) solid solutions have been synthesized. • Lanthanide photoluminescence of Y{sub 2−n}A{sub n}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er; n=0.02–2) solid solutions has been studied. • Optimum concentration of each photoluminescent dopant for Y{sub 2−n}A{sub n}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er; n=0.02 –2) solid solutions has been determined. • Red photoemission of Eu{sup 3+} in Y{sub 1.5}Eu{sub 0.5}Mo{sub 4}Sb{sub 2}O{sub 18} is visible to the naked eye. • Green photoemission of Tb{sup 3+} in Y{sub 1.7}Tb{sub 0.3}Mo{sub 4}Sb{sub 2}O{sub 18} is visible to the naked eye.

  5. Correlation between slow magnetic relaxation and the coordination structures of a family of linear trinuclear Zn(II)-Ln(III)-Zn(II) complexes (Ln = Tb, Dy, Ho, Er, Tm and Yb).

    Science.gov (United States)

    Maeda, Moe; Hino, Shiori; Yamashita, Kei; Kataoka, Yumiko; Nakano, Motohiro; Yamamura, Tomoo; Kajiwara, Takashi

    2012-11-28

    Six linear trinuclear [Ln{Zn(L)(AcO)}(2)]BPh(4) complexes (H(2)L denotes the Schiff-base ligand formed by a condensation reaction between ethylenediamine and two equivalents of o-vanillin), including Ln = Tb (1), Dy (2), Ho (3), Er (4), Tm (5) and Yb (6) were synthesized and were confirmed to be isostructural via X-ray crystallographic analyses. The Ln(III) ion in each complex is deca-coordinated by four equatorial oxygen donors from the methoxo groups of the Schiff-base ligands, two oxygen donors from the acetate anions and four axial oxygen donors from the phenoxo groups of the Schiff-base ligands. AC susceptibility measurements, with an oscillating frequency of 10 to 10,000 Hz, revealed that 1, 2, 4 and 6 show slow magnetic relaxation under a 1000 Oe DC bias field, which occurs via a single process, as confirmed by the semi-circular Cole-Cole plots. These complexes are considered to be field-induced single-molecule magnets under these conditions. The presence or absence of the slow magnetic relaxation process is discussed by correlating the characteristic magnetic anisotropy of each Ln(III) ion with the ligand field anisotropy.

  6. Canted magnetic ground state of quarter-doped manganites R 0.75Ca0.25MnO3 (R  =  Y, Tb, Dy, Ho, and Er)

    Science.gov (United States)

    Sinclair, R.; Cao, H. B.; Garlea, V. O.; Lee, M.; Choi, E. S.; Dun, Z. L.; Dong, S.; Dagotto, E.; Zhou, H. D.

    2017-02-01

    Polycrystalline samples of the quarter-doped manganites R 0.75Ca0.25MnO3 (R  =  Y, Tb, Dy, Ho, and Er) were studied by x-ray diffraction and AC/DC susceptibility measurements. All five samples are orthorhombic and exhibit similar magnetic properties: enhanced ferromagnetism below T 1 (∼80 K) and a spin glass (SG) state below T SG (∼30 K). With increasing R 3+ ionic size, both T 1 and T SG generally increase. The single crystal neutron diffraction results on Tb0.75Ca0.25MnO3 revealed that the SG state is mainly composed of a short-range ordered version of a novel canted (i.e. noncollinear) antiferromagnetic spin state. Furthermore, calculations based on the double exchange model for quarter-doped manganites reveal that this new magnetic phase provides a transition state between the ferromagnetic state and the theoretically predicted spin-orthogonal stripe phase.

  7. Crystal growth and scintillation properties of undoped and Ce3+-doped GdI3 crystals

    Science.gov (United States)

    Ye, Le; Li, Huanying; Wang, Chao; Shi, Jian; Chen, Xiaofeng; Wang, Zhongqing; Huang, Yuefeng; Xu, Jiayue; Ren, Guohao

    2017-02-01

    The growth and scintillation properties of undoped and Ce3+-doped GdI3 crystals were reported in this paper. These GdI3:χ%Ce (χ = 0, 1, 2) crystals were grown by the vertical Bridgman growth technique in evacuated quartz crucibles. X-ray excited optical luminescence spectra of GdI3:Ce exhibit a broad emission band (450 nm-650 nm) peaking at 520 nm corresponding to 5d1→4f1 transition of Ce3+ while the undoped GdI3 crystal consists of a broad band (400 nm-600 nm) and several sharp lines peaking at 462 nm, 482 nm, 492 nm, 549 nm, 579 nm owing to the impurities ions and defects. The excitation spectra of Ce3+ doped GdI3 consist of two broad bands between 300 nm and 500 nm corresponding to 4f1→5d1 absorption of Ce3+. The other absorption peaking at 262 nm in the spectrum of GdI3:2%Ce is assigned to band-to-band exciton transition. The excitation spectrum of undoped GdI3 contains a flat absorption band from 330 to 370 nm and a broad band between 390 and 450 nm peaking at 414 nm corresponding to the absorption of the unintentionally doped Ce3+, Dy3+, Ho3+ impurities and other defects. The emission spectrum of undoped GdI3 under 332 nm excitation has the identical line peaks with the spectrum measured under X-ray excitation. The emission spectra of GdI3:2%Ce and GdI3:1%Ce show a broad band in the range of 450-750 nm with the maximum at 550 nm corresponding to 5d1→4f1 transitions of Ce3+ ion. The GdI3, GdI3:1%Ce and GdI3:2%Ce show fast principle decay time constant 73 ns, 69 ns and 58 ns respectively, besides, the undoped also shows a slow decay constant 325 ns which doesn't appear in Ce3+-doped GdI3 crystal. The energy resolutions of GdI3:χ%Ce (χ = 1, 2) measured at 662 KeV are about 3%-5% and the undoped GdI3 is 13.3%.

  8. Single-molecule magnet behavior and magnetocaloric effect in ferromagnetically coupled Ln(III)-Ni(II)-Ni(II)-Ln(III) (Ln(III) = Dy(III) and Gd(III)) linear complexes.

    Science.gov (United States)

    Meseguer, Carlos; Titos-Padilla, Silvia; Hänninen, Mikko M; Navarrete, R; Mota, A J; Evangelisti, Marco; Ruiz, José; Colacio, Enrique

    2014-11-17

    New types of linear tetranuclear Ln(III)-Ni(II)-Ni(II)-Ln(III) (Ln(III) = Dy (1), Gd (2)) complexes have been prepared using the multidentate ligand N,N'-bis(3-methoxysalicylidene)-1,3-diaminobenzene, which has two sets of NO and OO' coordination pockets that are able to selectively accommodate Ni(II) and Ln(III) ions, respectively. The X-ray structure analysis reveals that the Ni(II) ions are bridged by phenylenediimine groups forming a 12-membered metallacycle in the central body of the complex, whereas the Ln(III) ions are located at both sides of the metallacycle and linked to the Ni(II) ions by diphenoxo bridging groups. Phenylenediimine and diphenoxo bridging groups transmit ferromagnetic exchange interactions between the two Ni(II) ions and between the Ni(II) and the Ln(III) ions, respectively. Complex 1 shows slow relaxation of the magnetization at zero field and a thermal energy barrier Ueff = 7.4 K with HDC = 1000 Oe, whereas complex 2 exhibits an S = 9 ground state and significant magnetocaloric effect (-ΔSm = 18.5 J kg(-1) K(-1) at T = 3 K and ΔB = 5 T).

  9. Synthesis, structural characterization, luminescent properties and theoretical study of three novel lanthanide metal-organic frameworks of Ho(III), Gd(III) and Eu(III) with 2,5-thiophenedicarboxylate anion

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Lippy F. [Instituto de Química, Universidade do Estado do Rio de Janeiro, Rio de Janeiro 20550-013 (Brazil); Correa, Charlane C. [Departamento de Química-ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG, 36036-330 (Brazil); Ribeiro, Sidney J.L.; Santos, Molíria V. dos [Institute of Chemistry, São Paulo State University − UNESP, CP 355 Araraquara-SP 14801-970 Brazil (Brazil); Dutra, José Diogo L.; Freire, Ricardo O. [Pople Computational Chemistry Laboratory, Departamento de Química, Universidade Federal de Sergipe, São Cristóvão-SE 49100-000 (Brazil); Machado, Flávia C., E-mail: flavia.machado@ufjf.edu.br [Departamento de Química-ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG, 36036-330 (Brazil)

    2015-07-15

    In this paper, the synthesis of three new metal-organic frameworks of lanthanides (LnMOFs) ([Ln{sub 2}(2,5-tdc){sub 3}(dmso){sub 2}]·H{sub 2}O){sub n} (Ln=Ho (1); Gd (2); Eu (3); 2,5-tdc=2,5-thiophenedicarboxylate anion; dmso=dimethylsulfoxide), and their complete characterization, including single crystal X-ray diffraction, FTIR spectroscopy and thermogravimetric analysis are reported. In especial, photophysical properties of Eu(III) complex have been studied in detail via both theoretical and experimental approaches. Crystal structure of (1) reveals that each lanthanide ion is seven-coordinated by oxygen atoms in an overall distorted capped trigonal – prismatic geometry. The 2,5-tdc{sup 2−} ligands connect four Ln(III) centers, adopting (κ{sup 1}–κ{sup 1})–(κ{sup 1}–κ{sup 1})–μ{sub 4} coordination mode, generating an 8-connected uninodal 3D network. In addition, theoretical studies for Eu(III) complex were performed using the Sparkle model for lanthanide complexes. - Graphical abstract: Three new metal-organic frameworks of lanthanides (LnMOFs) ([Ln{sub 2}(2,5-tdc){sub 3}(dmso){sub 2}]·H{sub 2}O){sub n} (Ln=Ho (1); Gd (2); Eu (3); 2,5-tdc=2,5-thiophenedicarboxylate anion; dmso=dimethylsulfoxide), were synthesized and their complete characterization, including single crystal X-ray diffraction, FTIR spectroscopy and thermogravimetric analysis are reported. In especial, photophysical properties of Eu(III) complex have been studied in detail via both theoretical and experimental approaches. - Highlights: • Three new LnMOFs were synthesized and fully characterized. • Ho{sup 3+}, Gd{sup 3+} and Eu{sup 3+} complexes photoluminescence properties were investigated. • Theoretical approaches for Eu{sup 3+} complex luminescence has been performed. • An energy level diagram is used to establish the ligand-to-metal energy transfer. • These metal−organic frameworks can act as light conversion molecular devices.

  10. Syntheses, structures, and magnetic properties of a family of tetranuclear hydroxido-bridged Ni(II)2Ln(III)2 (Ln = La, Gd, Tb, and Dy) complexes: display of slow magnetic relaxation by the zinc(II)-dysprosium(III) analogue.

    Science.gov (United States)

    Abtab, Sk Md Towsif; Maity, Manoranjan; Bhattacharya, Kisholoy; Sañudo, E Carolina; Chaudhury, Muktimoy

    2012-10-01

    A new family of [2 × 2] tetranuclear 3d-4f heterometallic complexes have been synthesized. These are [Zn(2)Dy(2)L(2)(μ(3)-OH)(2)(μ(4)-OH)(dbm)(2)(MeOH)(2)](NO(3))·2H(2)O·MeOH (3), [Ni(2)Dy(2)L(2)(μ(3)-OH)(2)(μ(4)-OH)(dbm)(2)(MeOH)(2)](NO(3))·MeOH (4), [Ni(2)La(2)L(2)(μ(3)-OH)(2)(μ(4)-OH)(dbm)(2)(MeOH)(2)](ClO(4))·H(2)O·2MeOH (5), [Ni(2)Tb(2)L(2)(μ(3)-OH)(2)(μ(4)-OH)(dbm)(2) (MeOH)(2)](NO(3))·MeOH (6), and [Ni(2)Gd(2)L(2)(μ(3)-OH)(2)(μ(4)-OH)(dbm)(2)(MeOH)(2)](NO(3))·MeOH (7), [H(2)L = N,N'-dimethyl-N,N'-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine and Hdbm = dibenzoylmethane] obtained through a single-pot synthesis using [Zn(HL)(dbm)] (for 3)/[Ni(HL)(dbm)]·2CH(3)OH (for 4, 5, 6, and 7) as 3d-metal ion precursors. Single-crystal X-ray diffraction analysis and electrospray ionization (ESI) mass spectroscopy have been used to establish their identities. Compounds are isostructural, in which the metal ions are all connected together by a bridging hydroxido ligand in a rare μ(4)-mode. In complexes 3-7, the metal ions are antiferromagnetically coupled. Taking a cue from the results of 3 and 5, precise estimations have been made for the antiferromagnetic Ni···Ni (J(Ni) = -50 cm(-1)), Ni···Gd (J(NiGd) = -4.65 cm(-1)), and Gd···Gd (J(Gd) = -0.02 cm(-1)) exchange interactions in 7, involving the gadolinium(III) ions. The Zn(II)(2)Dy(III)(2) compound 3 has shown the tail of an out-of-phase signal in alternating current (AC) susceptibility measurement, indicative of slow relaxation of magnetization. Interestingly, the Ni(II)(2)Dy(III)(2) compound 4 in which both the participating metal ions possess large single ion anisotropy, has failed to show up any slow magnetic relaxation.

  11. High-pressure syntheses, crystal structures, and thermal behaviour of {beta}-RE(BO{sub 2}){sub 3} (RE = Nd, Sm, Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Emme, H.; Heymann, G.; Haberer, A.; Huppertz, H. [Ludwig-Maximilians-Univ. Muenchen (Germany). Dept. Chemie und Biochemie

    2007-06-15

    The compounds {beta}-RE(BO{sub 2}){sub 3} [RE = Nd (neodymium meta-borate), Sm (samarium meta-borate) and Gd (gadolinium meta-borate)] were synthesized under high-pressure and high-temperature conditions in a Walker-type multianvil apparatus at 3.5 GPa (Nd), 7.5 GPa (Sm, Gd) and 1050 C. The crystal structures were determined by single crystal X-ray diffraction data collected at r. t. (Sm, Gd) and at -73 C (Nd), respectively. The structures are isotypic with the already known ambient-pressure phases {beta}-RE(BO{sub 2}){sub 3} (RE = (Tb, Dy)) and the high-pressure phases {beta}-RE(BO{sub 2}){sub 3} (RE = Ho.Lu). (orig.)

  12. Influence of electron beam irradiation on the structural, electrical and thermal properties of Gd{sub 0.5}Sr{sub 0.5}MnO{sub 3} and Dy{sub 0.5}Sr{sub 0.5}MnO{sub 3} manganites

    Energy Technology Data Exchange (ETDEWEB)

    Nagaraja, B.S. [Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Rao, Ashok, E-mail: ashokanu_rao@rediffmail.com [Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Babu, P.D. [UGC-DAE Consortium for Scientific Research, Mumbai Centre, BARC, Mumbai 400085 (India); Sanjeev, Ganesh [Microtron Centre, Department of Studies in Physics, Mangalore University, Mangalagangotri 574199, Karnataka (India); Okram, G.S. [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India)

    2016-01-01

    Highlights: • Pristine and irradiated samples follow small polaron hopping model in high temperature range. • Reduction in volume is seen via electron beam irradiation. • High temperature thermoelectric power data follows small polaron hopping model. • Electron beam irradiation enhances thermoelectric power for Gd{sub 0.5}Sr{sub 0.5}MnO{sub 3} compounds. - Abstract: We present systematic studies on the effect of electron beam irradiation on structural, electrical and thermal properties of Gd{sub 0.5}Sr{sub 0.5}MnO{sub 3} and Dy{sub 0.5}Sr{sub 0.5}MnO{sub 3} manganites. The XRD patterns and Rietveld analysis show that the samples remain single phased even after they undergo electron beam irradiation. Both the series of the samples Gd{sub 0.5}Sr{sub 0.5}MnO{sub 3} and Dy{sub 0.5}Sr{sub 0.5}MnO{sub 3} show insulating trends in their temperature dependent electrical resistivity, ρ(T) behavior. The resistivity data for both the series of samples (pristine as well as irradiated) indicate that the small polaron hopping model is valid in high temperature region; on contrary, variable range hopping model governs the low temperature regime. Magnetic studies demonstrate that the Neel temperatures of pristine and irradiated samples of Gd{sub 0.5}Sr{sub 0.5}MnO{sub 3} and Dy{sub 0.5}Sr{sub 0.5}MnO{sub 3} do not change appreciably when they are subjected to irradiation. Thermo-electrical power is observed to increase with irradiation in Gd{sub 0.5}Sr{sub 0.5}MnO{sub 3} samples, whereas for Dy{sub 0.5}Sr{sub 0.5}MnO{sub 3} samples a decrease in thermo-electric power is seen when the samples are irradiated.

  13. Magnetic properties and magnetic structures of RCo{sub x}Sn{sub 2} (R=Gd-Er) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gil, A.; Penc, B.; Wawrzynska, E.; Hernandez-Velasco, J.; Szytula, A.; Zygmunt, A

    2004-02-25

    Magnetic properties of RCo{sub x}Sn{sub 2} (R=Gd-Er) stannides, determined on the basis of magnetic and powder diffraction data, are reported. The compounds crystallize in the orthorhombic CeNiSn{sub 2}-type structure. Magnetic and neutron diffraction measurements (the latter for R=Tb and Ho) show that all the compounds are antiferromagnets with Neel temperatures of 16.5 K (R=Gd), 18.8 K (R=Tb), 7 K (R=Dy), 5.6 K (R=Ho) and 4.5 K (R=Er). The neutron diffraction data indicate the presence of collinear magnetic structures described by the propagation vector k=(0, 0, ((1)/(2))) for R=Tb and k=(((1)/(2)), ((1)/(2)), 0) for R=Ho. The determined magnetic structures of RCo{sub x}Sn{sub 2} (R=Tb, Ho) are similar to those observed in the isostructural RNi{sub x}Sn{sub 2}.

  14. Lanthanide substitution by high pressure in the RuSr{sub 2}GdCu{sub 2}O{sub 8} magnetic superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Bustos, R.; Gallardo-Amores, J.M.; Saez-Puche, R.; Moran, E.; Alario-Franco, M.A

    2002-11-15

    A systematic study of the structural and magnetic properties of the family RuSr{sub 2}RECu{sub 2}O{sub 8} (RE=Er, Ho, Y, Dy, Tb, Gd and Eu) has been performed. All these materials appear to be tetragonal (P4/mmm) and the unit cell volume decreases along with the lanthanide ion dimension. Differences are observed in the magnetic behaviour of these compounds. High pressure and high temperature are needed to synthesize most of the members of this family.

  15. An Undecanuclear Ferrimagnetic Cu9Dy2 Single Molecule Magnet Achieved through Ligand Fine-Tuning.

    Science.gov (United States)

    Kühne, Irina A; Kostakis, George E; Anson, Christopher E; Powell, Annie K

    2016-05-02

    We describe the concept of increasing the nuclearity of a previously reported high-spin Cu5Gd2 core using a "fine-tuning" ligand approach. Thus, two Cu9Ln2 coordination clusters, with Ln = Dy (1) and Gd (2), were synthesized with the Gd compound having a ground spin state of (17)/2 and the Dy analogue showing single-molecule-magnet behavior in zero field.

  16. ПОЛУЧЕНИЕ ПОРОШКОВ ТВЕРДЫХ РАСТВОРОВ SR(ND, GD)S4, SR(DY, ER)S4

    OpenAIRE

    Елышев, Андрей; Андреев, Олег

    2011-01-01

    Установлена последовательность фазовых превращений, происходящих при сульфидировании шихты SrO, Nd2O3, Gd2O3; SrO, Dy2O3, Er2O3, с образованием порошков твердых растворов Sr(NdGd)S4, с кубической структурой типа Th3P4, Sr(DyEr)S4 ромбической структурой типа CaFe2O4.

  17. Structural and conductivity properties of Bi{sub 0.775}Ln{sub 0.225}O{sub 1.5} oxide conductors (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy) with rhombohedral Bi-Sr-O type

    Energy Technology Data Exchange (ETDEWEB)

    Drache, M.; Obbade, S.; Wignacourt, J.P.; Conflant, P. [USTL-ENSCL, Villeneuve d`Ascq (France). Lab. de Cristallochimie et Physicochimie du Solide

    1999-02-01

    This paper deals with structural and conductivity properties of the dimorphic Bi{sub 0.775}Ln{sub 0.225}O{sub 1.5} (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy) hexagonal structure layer phases with rhombohedral Bi-Sr-O type. The evolutions, versus Ln{sub VI}{sup 3+} radius, of cell parameters, thermal expansion coefficients, electrical properties (conductivity and activation energy), and structural characteristics determined from Rietveld powder structure refinements, suggest two different domains (La-Sm) and (Gd-Dy), with the intermediate Eu sample, thus possibly characterizing two kinds of ordering in the mixed cationic layer. The best conductivity properties obtained for Bi{sub 0.775}La{sub 0.225}O{sub 1.5} ({sigma}{sub 400{degree}C} = 10{sup {minus}3} S cm{sup {minus}1} with E{sub a} = 0.8 eV) are discussed and justified.

  18. RE{sub 3}Au{sub 5}Zn (RE = Y, Sm, Gd-Ho). A new structure type with five- and six-membered rings as building units in a gold network

    Energy Technology Data Exchange (ETDEWEB)

    Gerke, Birgit; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie and NRW Graduate School of Chemistry

    2016-08-01

    RE{sub 3}Au{sub 5}Zn (RE = Y, Sm, Gd-Ho) intermetallic compounds were synthesized by melting the elements in sealed tantalum tubes. They exhibit a new structure type which was studied by X-ray diffraction on powders and refined from single crystal diffraction data: Cmcm, a = 736.9(2), b = 1489.4(2), c = 1330.4(3) pm, wR2 = 0.0371, 1184 F{sup 2} values and 55 variables for Y{sub 3}Au{sub 4.92}Zn{sub 1.08} and a = 739.0(1), b = 1495.8(2), c = 1339.2(2) pm, wR2 = 0.0325, 1410 F{sup 2} values and 54 variables for Tb{sub 3}Au{sub 5}Zn. The network consists of five- and six-membered gold rings in puckered conformations. Atoms of the rare earth elements are placed within the cavities of this network where every third cavity is filled by a Zn{sub 2} dumbbell. The structure is discussed in detail and compared with the gold substructure of Hf{sub 7}Au{sub 10}.

  19. Chemical ordering in substituted fluorite oxides: a computational investigation of Ho2Zr2O7 and RE2Th2O7 (RE=Ho, Y, Gd, Nd, La)

    Science.gov (United States)

    Solomon, Jonathan M.; Shamblin, Jacob; Lang, Maik; Navrotsky, Alexandra; Asta, Mark

    2016-12-01

    Fluorite-structured oxides find widespread use for applications spanning nuclear energy and waste containment, energy conversion, and sensing. In such applications the host tetravalent cation is often partially substituted by trivalent cations, with an associated formation of charge-compensating oxygen vacancies. The stability and properties of such materials are known to be influenced strongly by chemical ordering of the cations and vacancies, and the nature of such ordering and associated energetics are thus of considerable interest. Here we employ density-functional theory (DFT) calculations to study the structure and energetics of cation and oxygen-vacancy ordering in Ho2Zr2O7. In a recent neutron total scattering study, solid solutions in this system were reported to feature local chemical ordering based on the fluorite-derivative weberite structure. The calculations show a preferred chemical ordering qualitatively consistent with these findings, and yield values for the ordering energy of 9.5 kJ/mol-cation. Similar DFT calculations are applied to additional RE2Th2O7 fluorite compounds, spanning a range of values for the ratio of the tetravalent and trivalent (RE) cation radii. The results demonstrate that weberite-type order becomes destabilized with increasing values of this size ratio, consistent with an increasing energetic preference for the tetravalent cations to have higher oxygen coordination.

  20. Double symmetry breaking in TmFe{sub 4}Ge{sub 2} compared to RFe{sub 4}Ge{sub 2} (R=Y, Lu, Er, Ho, Dy) magnetic behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Schobinger-Papamantellos, P., E-mail: Schobinger@mat.ethz.ch [Laboratory of Crystallography, ETH-Zürich, 8093 Zürich (Switzerland); Buschow, K.H.J. [Van der Waals-Zeeman Institute, University of Amsterdam, NL-1018 XE (Netherlands); Rodríguez-Carvajal, J. [Institut Laue-Langevin, 156X, 38042 Grenoble Cédex (France)

    2014-04-15

    TmFe4Ge{sub 2} undergoes a double magneto-elastic first order transition at T{sub N},T{sub c} where the high temperature (HT) tetragonal phase disproportionate into two distinct orthorhombic low temperature (LT) phases with commensurate and incommensurate magnetic wave vectors respectively: P4{sub 2}/mnm(HT)T{sub N},T{sub c}→Cmmmq{sub 1}=(0,1/2 ,0)+Pnnm(q{sub 2}=(0,q{sub y},0),q{sub y}≈2/11(LT) Neutron diffraction shows the relative portions of the LT Cmmm and Pnnm competing phases change linearly with T. The amount of the majority HT phase Pnnm (54% at 30 K) decreases linearly to 30% down to 10 K in favour of the Cmmm phase that dominates the range 26–1.5 K. The Tm moments point along the c-axis in both phases while the Fe moments have canted arrangements. The μ{sub Tm}=3.54(3) μ{sub B}/atom at 1.5 K is strongly reduced below the Tm{sup 3+} free ion value g{sub J}J=7 μ{sub B} for the q{sub 1} phase. The q{sub 2} phase corresponds to a 3D canted sinusoidal arrangement. The results are summarised on a phase diagram and compared to the findings in RFe{sub 4}Ge{sub 2} (R=Y, Lu, Er, Ho, Dy) that are reviewed. The multitude of transition paths occurring in those systems arise from the competing magnetoelastic mechanisms involving the R-crystal field anisotropy, the exchange interactions R–R, R–Fe, Fe–Fe of the two sublattices and their coupling to the lattice strain. The geometrical frustration emerging from the compact tetrahedral Fe arrangement with antiferromagnetic interactions leads to 2D and 3D canted, incommensurate and non-magnetic states. The Cmmm transition is triggered by dominating R–R and R–Fe interactions becoming stronger at LT while the Pnnm phase is promoted by Fe–Fe and R–Fe interactions that prevail at HT. Included is also the magnetic structure of the ferromagnetic impurity phase Fe{sub 3}Ge. - Highlights: • Magnetic phase diagram of tetragonal TmFe{sub 4}Ge{sub 2} compound studied by neutron diffraction. • Unusual first

  1. β-delayed proton decay of the proton drip-line nucleus 142Ho in the rare-earth region

    Institute of Scientific and Technical Information of China (English)

    XU; Shuwei(徐树威); LI; Zhankui(李占奎); XIE; Yuanxiang(谢元祥); XU; Furong(徐甫荣); WANG; Xudong(王旭东); GUO; Bin(郭斌); LENG; Changgeng(冷长庚); YU; Yong(于涌); WANG; Chunfang(王春芳); XING; Jianping(邢建萍); CHEN; Hongyan(陈红艳)

    2003-01-01

    New β-delayed proton precursor 142Ho was produced via heavy ion induced reaction 106Cd(40Ca, p3n), and identified for the first time by using a He-jet fast tape transport system in combination with "p-γ" coincidence measurements. The β-delayed proton decay of 142Ho was observed and its half life was determined to be (0.4±0.1) s. By fitting the experimental relative branching ratios to final states in the proton daughter nucleus 141Tb and the energy spectrum of β-delayed protons with a statistical model calculation, the ground-state spin of 142Ho was assigned as 5, 6 or 7. Nuclear energy-potential-surface (EPS) calculations were performed using the Woods-Saxon Strutinsky method. The calculated results favored the assignments of 7- to 142Ho. AS the by-products, some γ-transitions in the proton daughter nuclei following the β-delayed proton decays of precursors 139Gd, 140Tb, 142Tb, and 143Dy were reported here for the first time.

  2. Výchova ke zdraví v učebnicích 1. stupně ZŠ: výsledky analýzy didaktického aparátu učebnic prvouky/přírodovědy/Health education in primary school textbooks – results of a content analysis

    Directory of Open Access Journals (Sweden)

    Markéta Hrozová

    2015-02-01

    Full Text Available Cílem empirické studie je prezentace výsledků obsahové analýzy didaktického aparátu učebnic a cvičebnic školního vzdělávacího předmětu prvouka/přírodověda určených pro žáky 1. stupně základních škol z hlediska jejich zaměření na výchovu ke zdraví. V první části studie prezentujeme teoretický základ našeho výzkumu, který spočíval ve vymezení analytických kategorií vyplývajících z holistického pojetí zdraví. V druhé části představujeme cíle a metody výzkumu, výzkumný vzorek sestávající z pěti současných ucelených učebnicových řad učebnic prvouky/ přírodovědy (38 učebnic/cvičebnic; 3136 zkoumaných jednotek, tedy otázek, námětů a úkolů zařazených do učebnic platných pro 1. stupeň základního vzdělávání. Třetí část je věnována výsledkům analýzy, která poukázala na významné rozdíly v prezentaci učiva v oblasti výchova ke zdraví. Z výsledků vyplývá nereflektování holistického pojetí zdraví v jeho plném rozsahu, majoritní zastoupení biologického kontextu zdraví ve zkoumaných učebnicích. Holistické pojetí zdraví nejvíce reflektují učebnice druhých ročníků. Dále poukazujeme na významné rozdíly ve strukturaci učiva v rámci jednotlivých učebnicových řad (absence tematiky zdraví ve většině zkoumaných učebnic 4. ročníků a nestabilitu v distribuci tematických celků zkoumaného vzorku učebnic. V závěru studie (čtvrtá a pátá část jsou diskutovány výsledky, možnosti a limity studie a představujeme eventuality navazujícího výzkumného šetření.

  3. Magnetic and transport properties of i-R-Cd icosahedral quasicrystals (R=Y, Gd-Tm)

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Tai [Ames Laboratory; Bud' ko, Sergey L. [Ames Laboratory; Jesche, Anton [Ames Laboratory; McArthur, John [Quantum Design Japan; Kreyssig, Andreas [Ames Laboratory; Goldman, Alan I. [Ames Laboratory; Canfield, Paul C. [Ames Laboratory

    2014-07-01

    We present a detailed characterization of the recently discovered i-R-Cd (R=Y,Gd-Tm) binary quasicrystals by means of x-ray diffraction, temperature-dependent dc and ac magnetization, temperature-dependent resistance, and temperature-dependent specific heat measurements. Structurally, the broadening of x-ray diffraction peaks found for i-R-Cd is dominated by frozen-in phason strain, which is essentially independent of R. i-Y-Cd is weakly diamagnetic and manifests a temperature-independent susceptibility. i-Gd-Cd can be characterized as a spin glass below 4.6 K via dc magnetization cusp, a third order nonlinear magnetic susceptibility peak, a frequency-dependent freezing temperature, and a broad maximum in the specific heat. i-R-Cd (R=Ho-Tm) is similar to i-Gd-Cd in terms of features observed in thermodynamic measurements. i-Tb-Cd and i-Dy-Cd do not show a clear cusp in their zero-field-cooled dc magnetization data, but instead show a more rounded, broad local maximum. The resistivity for i-R-Cd is of order 300μΩ cm and weakly temperature dependent. The characteristic freezing temperatures for i-R-Cd (R=Gd-Tm) deviate from the de Gennes scaling, in a manner consistent with crystal electric field splitting induced local moment anisotropy.

  4. Role of some rare earth (RE) ions (RE = La, Pr, Nd, Sm, Gd and Dy) in crystal and mechanical behaviours of sol–gel derived ZrO2–2 mol% RE2O3 spun fibres calcined at 1300°C

    Indian Academy of Sciences (India)

    M K Naskar; M Chatterjee; D Ganguli

    2002-10-01

    Crystal behaviours such as crystallization temperature (amorphous to tetragonal () zirconia), tendency of phase transformation (tetragonal to monoclinic () zirconia) and lattice strain were studied with mechanical property e.g. tensile strength of sol–gel derived ZrO2–2 mol% RE2O3 (RE = La, Pr, Nd, Sm, Gd and Dy) spun fibres. Rare earth cations of varying sizes played a significant role in changing the above mentioned properties of ZrO2–2 mol% RE2O3 fibres. It was found that with decreasing the ionic size difference between the zirconium and RE ions, crystallization temperature (amorphous $\\rightarrow \\ t$-ZrO2) decreased, the probability of phase transformation ($t \\rightarrow m$) decreased, lattice strain which is related to lattice distortion decreased and tensile strength increased.

  5. Matrix-induced synthesis and photoluminescence of M{sub 3}Ln(VO{sub 4}){sub 3}:RE (M Ca, Sr, Ba; Ln = Y, Gd; RE = Eu{sup 3+}, Dy{sup 3+}, Er{sup 3+}) phosphors by hybrid precursors

    Energy Technology Data Exchange (ETDEWEB)

    Su Xueqing [Department of Chemistry, Tongji University, Shanghai 200092 (China); Yan, Bing [Department of Chemistry, Tongji University, Shanghai 200092 (China)]. E-mail: byan@tongji.edu.cn

    2006-09-14

    Using rare earth coordination polymers with salicylic acid as precursors, composing with the polyethylene glycol (PEG) as dispersing media, the phosphor particles of M{sub 3}Ln(VO{sub 4}){sub 3}:RE (M = Ca, Sr, Ba; Ln = Y, Gd; RE Eu{sup 3+}, Dy{sup 3+}, Er{sup 3+}) were firstly synthesized via a novel modified in situ chemical co-precipitation technology. Their micromorphology and particles have been analyzed by X-ray powder diffraction (XRD) and scanning electronic microscope (SEM), which indicate that these materials have the micrometer size. And all the characteristic transitions of the doped rare earth ions can be detected in all the host lattices.

  6. Normal coordinate analysis and DFT calculations of the vibrational spectra for lanthanide(III) complexes with 3-bromo-4-methoxy-2,6-lutidine N-oxide: LnCl 3(3Br4CH 3OC 7H 7NO) 3 (Ln=Pr, Nd, Sm, Eu, Gd, Dy)

    Science.gov (United States)

    Godlewska, P.; Ban-Oganowska, H.; Macalik, L.; Hanuza, J.; Oganowski, W.; Roszak, S.; Lipkowski, P.

    2006-01-01

    The results of the FT-Raman and FT-IR studies of the LnCl 3(LNO) 3 type complexes (where Ln=Pr, Nd, Sm, Eu, Gd, Dy and LNO=3-Br-4-CH 3OC 7H 7NO) are presented. The spectral contours observed in the regions of the lanthanide-oxygen, lanthanide-chlorine and nitrogen-oxygen vibrations are employed in the discussion of the molecular structure of the complex ions and the local symmetry of the LnCl 3(ON) 3 polyhedron. The discussion of the vibrational spectra is based on the classical normal coordinate analysis and its results are compared to the results of DFT quantum chemical calculations performed for complete molecule. The normal coordinate analysis has been performed for PrCl 3(ON) 3 and DyCl 3(ON) 3 molecular systems, which have been treated as a different 'isotopic units'. Basing on the predominant PED contributions of the respective internal coordinates the assignment of the normal vibrations has been proposed.

  7. Carbonato-bridged Ni(II)2Ln(III)2 (Ln(III) = Gd(III), Tb(III), Dy(III)) complexes generated by atmospheric CO2 fixation and their single-molecule-magnet behavior: [(μ4-CO3)2{Ni(II)(3-MeOsaltn)(MeOH or H2O)Ln(III)(NO3)}2]·solvent [3-MeOsaltn = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato].

    Science.gov (United States)

    Sakamoto, Soichiro; Fujinami, Takeshi; Nishi, Koshiro; Matsumoto, Naohide; Mochida, Naotaka; Ishida, Takayuki; Sunatsuki, Yukinari; Re, Nazzareno

    2013-06-17

    Atmospheric CO2 fixation of [Ni(II)(3-MeOsaltn)(H2O)2]·2.5H2O [3-MeOsaltn = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato], Ln(III)(NO3)3·6H2O, and triethylamine occurred in methanol/acetone, giving a first series of carbonato-bridged Ni(II)2Ln(III)2 complexes [(μ4-CO3)2{Ni(II)(3-MeOsaltn)(MeOH)Ln(III)(NO3)}2] (1Gd, 1Tb, and 1Dy). When the reaction was carried out in acetonitrile/water, it gave a second series of complexes [(μ4-CO3)2{Ni(II)(3-MeOsaltn)(H2O)Ln(III)(NO3)}2]·2CH3CN·2H2O (2Gd, 2Tb, and 2Dy). For both series, each Ni(II)2Ln(III)2 structure can be described as two di-μ-phenoxo-bridged Ni(II)Ln(III) binuclear units bridged by two carbonato CO3(2-) units to form a carbonato-bridged (μ4-CO3)2{Ni(II)2Ln(III)2} structure. The high-spin Ni(II) ion has octahedral coordination geometry, and the Ln(III) ion is coordinated by O9 donor atoms from Ni(II)(3-MeOsaltn), bidentate NO3(-), and one and two oxygen atoms of two CO3(2-) ions. The NO3(-) ion for the first series roughly lie on Ln-O(methoxy) bonds and are tilted toward the outside, while for the second series, the two oxygen atoms roughly lie on one of the Ln-O(phenoxy) bonds due to the intramolecular hydrogen bond. The temperature-dependent magnetic susceptibilities indicated a ferromagnetic interaction between the Ni(II) and Ln(III) ions (Ln(III) = Gd(III), Tb(III), Dy(III)) for all of the complexes, with a distinctly different magnetic behavior between the two series in the lowest-temperature region due to the Ln(III)-Ln(III) magnetic interaction and/or different magnetic anisotropies of the Tb(III) or Dy(III) ion. Alternating-current susceptibility measurements under the 0 and 1000 Oe direct-current (dc) bias fields showed no magnetic relaxation for the Ni(II)2Gd(III)2 complexes but exhibited an out-of-phase signal for Ni(II)2Tb(III)2 and Ni(II)2Dy(III)2, indicative of slow relaxation of magnetization. The energy barriers, Δ/kB, for the spin flipping were estimated from the Arrhenius

  8. Facile synthesis, structural and spectroscopic properties of GdF{sub 3}:Ce{sup 3+}, Ln{sup 3+} (Ln{sup 3+}=Sm{sup 3+}, Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanocrystals with bright multicolor luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Grzyb, Tomasz; Runowski, Marcin; Lis, Stefan, E-mail: blis@amu.edu.pl

    2014-10-15

    Hexagonal gadolinium fluorides doped with Ce{sup 3+} ions and co-doped with Sm{sup 3+}, Eu{sup 3+}, Tb{sup 3+} or Dy{sup 3+} were successfully synthesized via a simple co-precipitation approach, in the presence of glycerin as a capping agent. These fluorides, as solids or in aqueous solutions, showed intense, multicolored luminescence depending on the lanthanide ions used. The structures of the products were confirmed by powder X-ray diffraction (XRD). The morphologies of the synthesized nanophosphors were examined using transmission electron microscopy (TEM). The TEM results showed that the crystallites had shapes that varied with the dopant ion used. The spectroscopic properties: excitation spectra, emission spectra and luminescence decays were recorded and studied in detail. Bright luminescences from all of the products were triggered by effective energy transfer between the ions embedded in their structures. The mechanism for this phenomenon was also proposed. All of the synthesized products formed stable aqueous colloids, exhibiting brightly multicolored luminescence under UV light irradiation. - Highlights: • Hexagonal GdF{sub 3}:Ce{sup 3+}, Ln{sup 3+} nanocrystals were synthesized by a co-precipitation method. • Nanocrystals formed stable water colloids. • Multicolor luminescence under UV light was observed. • Energy transfer mechanism between Gd{sup 3+}, Ce{sup 3+} and Ln{sup 3+} ions was proposed.

  9. Isolation of {sup 163}Ho from dysprosium target material by HPLC for neutrino mass measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mocko, Veronika; Taylor, Wayne A.; Nortier, Francois M.; Engle, Jonathan W.; Pollington, Anthony D.; Kunde, Gerd J.; Rabin, Michael W.; Birnbaum, Eva R. [Los Alamos National Laboratory, Los Alamos, NM (United States). Chemistry Div.; Barnhart, Todd E.; Nickles, Robert J. [Univ. Wisconsinn, Madison, WI (United States). Dept. of Medical Physics

    2015-07-01

    The rare earth isotope {sup 163}Ho is of interest for neutrino mass measurements. This report describes the isolation of {sup 163}Ho from a proton-irradiated dysprosium target and its purification. A Dy metal target was irradiated with 16 MeV protons for 10 h. After target dissolution, {sup 163}Ho was separated from the bulk Dy via cation-exchange high performance liquid chromatography using 70 mmol dm{sup -3} α-hydroxyisobutyric acid as the mobile phase. Subsequent purification of the collected Ho fraction was performed to remove the α-hydroxyisobutyrate chelating agent and to concentrate the Ho in a low ionic strength aqueous matrix. The final solution was characterized by MC-ICP-MS to determine the {sup 163}Ho/{sup 165}Ho ratio, {sup 163}Ho and the residual Dy content. The HPLC purification process resulted in a decontamination factor 1.4 x 10{sup 5} for Dy. The isolated Ho fraction contained 24.8 ± 1.3 ng of {sup 163}Ho corresponding to holmium recovery of 72 ± 3%.

  10. Upconversion luminescence in BaYF{sub 5}, BaGdF{sub 5} and BaLuF{sub 5} nanocrystals doped with Yb{sup 3+}/Ho{sup 3+}, Yb{sup 3+}/Er{sup 3+} or Yb{sup 3+}/Tm{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Grzyb, Tomasz, E-mail: tgrzyb@amu.edu.pl [Department of Rare Earths, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań (Poland); Balabhadra, Sangeetha [Department of Physics, University of Aveiro, Campus Universitario de Santiago, 3810-193, Aveiro (Portugal); Przybylska, Dominika; Węcławiak, Mariusz [Department of Rare Earths, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań (Poland)

    2015-11-15

    Nanomaterials based on BaREF{sub 5} fluorides (where RE = Y, Gd and Lu), doped with lanthanide ions Yb{sup 3+}/Ln{sup 3+} (Ln{sup 3+} = Er, Ho or Tm) were synthesized by microwave assisted hydrothermal method. The method of synthesis, structural and morphological properties are reported and discussed. The products obtained showed visible upconversion luminescence excited by the laser light of wavelength of 975 nm as a consequence of energy transfer between Yb{sup 3+} and remaining Ln{sup 3+} dopant ions. Their spectroscopic properties were characterized on the basis of excitation and emission spectra. Also luminescence decays and emission power dependences are presented and analysed. The materials compared revealed differences in their structural properties, reflected in their spectroscopic characteristics. The most intense luminescence was recorded for BaLuF{sub 5} based materials which exhibited upconversion also as water colloids. - Highlights: • BaREF{sub 5} nanomaterials (RE = Y, Gd or Lu) were synthesized by hydrothermal method. • Upconversion in BaREF{sub 5}:Yb{sup 3+}, Ln{sup 3+} (Ln = Ho, Er, Tm) nanocrystals was compared. • Mechanism of upconversion was analysed.

  11. 电感耦合等离子体质谱法测定铀铌混合氧化物中的钐、铕、钆、镝%Determination of Trace Amounts of Sm,Eu,Gd and Dy in U-Nb Mixed Oxide by Inductively Coupled Plasma Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    龙绍军; 廖志海; 安身平; 王鹏; 乔洪波; 郭蓉; 费浩

    2014-01-01

    建立了应用电感耦合等离子体质谱(ICP-MS)测定铀铌混合氧化物中痕量的稀土元素(Sm、Eu、Gd、Dy)的方法。这四种稀土元素在核燃料中的含量在10-7 g/g以下,但热中子截面很大,准确测定其在核燃料中的含量对于核燃料的研究至关重要。样品经 HNO3-HF 快速溶解后,应用 CL-TBP 萃淋树脂分离 U 基体,以115 In作为测定内标校正基体干扰和仪器漂移,标准模式下应用 ICP-MS定量测定淋洗液中 Sm、Eu、Gd和 Dy,半定量分析基体 U。四种稀土元素的质量浓度为0.01~1.00μg/L,线性关系良好,线性相关系数(r)均大于0.999,检出限为0.001~0.002μg/L。对于添加0.2μg/L的稀土元素,稀土元素的回收率为84.3%~97.3%,相对标准偏差(s r )为5.3%~8.7%(n=6),能够满足实际样品测定需要。%A method was developed for determination of trace rare earth elements (Sm,Eu, Gd and Dy )in U-Nb mixed oxide using inductively coupled plasma mass spectrometry (ICP-MS).Though the contents of these four rare earth elements in nuclear fuel are below 10-7 g/g, the accurate determination of their contents in nuclear fuel is crucially important to the research of nuclear fuel for their thermal neutron-absorption cross-sections are large.After the sample was dissolved fast by HNO3-HF acids,U matrix was separated using CL-TBP extraction resin.115 In was used as internal standard to correct matrix interference and instru-ment drift for quantitative determination of Sm,Eu,Gd and Dy in eluate,semi-quantitative determination of U in eluate by ICP-MS.The method has a good linear correlation (r>0.999)in the range of 0.01-1.00μg/L and the detection limit is between 0.001-0.002μg/L. For the add concentrations of rare earth elements is 0.2 μg/L,the recovery is between 84.3%-97.3% and the relative standard deviation (sr)is between 5.3%-8.7% (n=6).The method can be available in practical application.

  12. Sulfate Exchange of the Nitrate-Type Layered Hydroxide Nanosheets of Ln2(OH)5NO3· nH2O for Better Dispersed and Multi-color Luminescent Ln2O3 Nanophosphors (Ln = Y0.98RE0.02, RE = Pr, Sm, Eu, Tb, Dy, Ho, Er, and Tm)

    Science.gov (United States)

    Wu, Xiaoli; Liu, Weigang; Li, Ji-Guang; Zhu, Qi; Li, Xiaodong; Sun, Xudong

    2016-07-01

    Through restricting thickness growth by performing coprecipitation at the freezing temperature of ~4 °C, solid-solution nanosheets (up to 5-nm thick) of the Ln2(OH)5NO3· nH2O layered hydroxide (Ln = Y0.98RE0.02; RE = Pr, Sm, Eu, Tb, Dy, Ho, Er, and Tm, respectively) were directly synthesized without performing conventional exfoliation. In situ exchange of the interlayer NO3 - with SO4 2- produced a sulfate derivative [Ln2(OH)5(SO4)0.5· nH2O] of the same layered structure and two-dimensional crystallite morphology but substantially contracted d 002 basal spacing (from ~0.886 to 0.841 nm). The sulfate derivative was systematically compared against its nitrate parent in terms of crystal structure and phase/morphology evolution upon heating. It is shown that the interlayer SO4 2-, owing to its bonding with the hydroxide main layer, significantly raises the decomposition temperature from ~600 to 1000 °C to yield remarkably better dispersed oxide nanopowders via a monoclinic Ln2O2SO4 intermediate. The resultant (Y0.98RE0.02)2O3 nanophosphors were studied for their photoluminescence to show that the emission color, depending on RE3+, spans a wide range in the Commission Internationale de l'Eclairage (CIE) chromaticity diagram, from blue to deep red via green, yellow, orange, and orange red.

  13. Search for excited superdeformed bands in {sup 151}Dy

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

    1995-08-01

    Following the first report of superdeformed (SD) bands with identical transition energies in the pairs ({sup 151}Tb*,{sup 152}Dy), ({sup 150}Gd*, {sup 151}Tb) and ({sup 153}Dy*, {sup 152}Dy) (where * denotes an excited SD band), it was proposed by Nazarewicz et al. that the observations could be understood in a strong-coupling approach if pseudo SU(3) symmetry were invoked. In this model there are three limiting values of the decoupling parameter; i.e. a = 0, {plus_minus}1. In the first two cases mentioned above the pairs of bands have nearly identical transition energies and are interpreted as proton excitations involving the [200]1/2 pseudospin orbital coupled to the {sup 152}Dy core, for which the value of the decoupling parameter is calculated to be a =+1.

  14. Studies on Structural and Morphological Properties of Multidoped Ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ (x=0.2 as Solid Solutions

    Directory of Open Access Journals (Sweden)

    Marija Stojmenović

    2016-01-01

    Full Text Available The nanopowdery solid solutions of multidoped ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ (x=0.2 with the fluorite type crystal structure of CeO2 were synthesized for the first time. Two synthesis procedures were applied: the modified glycine-nitrate procedure (MGNP method and room temperature self-propagating reaction (SPRT method. All nanopowders were characterized by XRPD analysis, Raman spectroscopy, low temperature nitrogen physisorption, TEM, and SEM methods. According to the XRPD and Raman spectroscopy results, single phase solid solutions of fluorite structure were evidenced regardless of the number of dopants and synthesis procedure. Both XRPD and TEM were analyses evidenced nanometer particle dimensions. The SPRT method results in obtaining sample with higher specific surface area, smaller crystallite and particles sizes, and the same values of the lattice parameter in comparison to pure CeO2. Raman spectroscopy was confirmed to the oxygen vacancies introduced into the ceria lattice when Ce4+ ions were replaced with cations (dopants of lower valence state (3+, which may indicate the potential improvement of ionic conductivity. Additionally, the presence of oxygen vacancies in the lattice ceria, as well as very developed grain boundaries, gives a new possibility for potential application of obtained nanopowders in the area of room temperature ferromagnetism as spintronics.

  15. Studies on Structural and Morphological Properties of Multidoped Ceria Ce 0.8 Nd 0.0025 Sm 0.0025 Gd 0.005 Dy 0.095 Y 0.095 O 2 - δ ( x = 0.2 ) as Solid Solutions

    KAUST Repository

    Stojmenović, Marija

    2016-04-17

    The nanopowdery solid solutions of multidoped ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095 () with the fluorite type crystal structure of CeO2 were synthesized for the first time. Two synthesis procedures were applied: the modified glycine-nitrate procedure (MGNP method) and room temperature self-propagating reaction (SPRT method). All nanopowders were characterized by XRPD analysis, Raman spectroscopy, low temperature nitrogen physisorption, TEM, and SEM methods. According to the XRPD and Raman spectroscopy results, single phase solid solutions of fluorite structure were evidenced regardless of the number of dopants and synthesis procedure. Both XRPD and TEM were analyses evidenced nanometer particle dimensions. The SPRT method results in obtaining sample with higher specific surface area, smaller crystallite and particles sizes, and the same values of the lattice parameter in comparison to pure CeO2. Raman spectroscopy was confirmed to the oxygen vacancies introduced into the ceria lattice when Ce4+ ions were replaced with cations (dopants) of lower valence state (3+), which may indicate the potential improvement of ionic conductivity. Additionally, the presence of oxygen vacancies in the lattice ceria, as well as very developed grain boundaries, gives a new possibility for potential application of obtained nanopowders in the area of room temperature ferromagnetism as spintronics.

  16. Etude structurale des sulfotellurures de terres rares ( LS) 2Te 1 + x ( L = Tb, Dy, Ho, Er, Tm et Y). II. Surstructure des phases ordonnées. Macles d'ordre

    Science.gov (United States)

    Ghémard, Geneviève; Etienne, Jean; Schiffmacher, Gérard; Flahaut, Jean

    1982-11-01

    The ( LS) 2Te 1 + x compounds have an orthorhombic subcell, with a layered structure and vacant Te sites, and a monoclinic superstructure ( a = b = 6.658, c = 13.657 Å, γ = 102°43' for (HoS) 2Te 1.34). The order-disorder transition occurs at about 450°C. In the superstructure Te planes between ( L4S) tetrahedra layers are ordered with {B2}/{m} symmetry; however, some sites remain partially vacant. The S atoms conserve mmm symmetry, but the metallic atoms are slightly displaced from their substructure position ( R = 0.037). Ordering occurs so that each Te plane can be oriented in two different ways. Therefore, there are two kinds of domains, with respect to a twinning rule. These domains are observed by direct-imaging high-resolution electronic microscopy and are about 100 Å wide.

  17. Etude structurale des sulfotellurures de terres rares ( LS) 2Te 1+ x ( L = Tb, Dy, Ho, Er, Tm et Y). I. Sous-structure de la phase ordonnée de (HoS) 2Te 1,34. Structure de la phase desordonnée de (TbS) 2Te

    Science.gov (United States)

    Ghémard, G.; Etienne, J.; Flahaut, J.

    1982-11-01

    The lanthanide sulfotellurides ( LS) 2Te 1+ x (0 ≤ x < 0.50) show order-disorder phenomena. Above 450°C, they crystallize in a partially disordered structure, orthorhombic with cell parameters a, b, and c close to 4.1, 5.2, and 13.6 Å, respectively. This structure is determined from diffractometer data on a (HoS) 2Te 1.34 crystal ( R = 0.061). It is built up along the c axis from ( L4S) tetrahedra layers, separated by Te planes. Disorder and nonstoichiometry are related to the two vacant Te sites.

  18. BaFCl晶体中三价稀土离子Sm3+、Eu3+、Gd3+、Ho3+、Er3+和Yb3+的电荷转移激发%Charge Transfer Excitation of Rare Earth Ions (Sm3+, Eu3+, Gtl2+, Ho3+, Er3+ and Yb3+) Emission in BaFCl Crystal

    Institute of Scientific and Technical Information of China (English)

    苏勉曾; 孙小平

    1986-01-01

    @@ 1962年Jфrgensen[1]提出了精细电子自旋配对能理论(RESPET),计算由配体提供一个电子、将具有4fq基态的Ln3+还原为具有4fq+1的Ln2+这个电荷转移过程(CT)的能量变化.计算公式为Jфrgensen指出了公式中各参数的意义,并给出了各稀土离子的N(S)、M(L)和P(S,L,J)等系数的值[2,3].我们合成了Sm3+、Eu3+、Gd3+、Ho3+、Er3+和yb3+离子激活的六种BaFCl晶体,测定了它们的激发光谱(图1).由光谱数据确定了它们的电荷转移带(CTS)的波长和波数(另一报告已证明Eu 3+的CTS位于242nm[4]),利用公式(1)对以上各三价希土离子的电荷转移带的能量进行了计算.

  19. Co(II)4, Co(II)7, and a Series of Co(II)2Ln(III) (Ln(III) = Nd(III), Sm(III), Gd(III), Tb(III), Dy(III)) Coordination Clusters: Search for Single Molecule Magnets.

    Science.gov (United States)

    Modak, Ritwik; Sikdar, Yeasin; Thuijs, Annaliese E; Christou, George; Goswami, Sanchita

    2016-10-03

    We report herein the syntheses and investigation of the magnetic properties of a Co(II)4 compound, a series of trinuclear Co(II)2Ln(III) (Ln(III) = Nd(III), Sm(III), Gd(III), Tb(III), Dy(III)) complexes, and a Co(II)7 complex. The homometallic Co(II)4 core was obtained from the reaction of Ln(NO3)3·xH2O/Co(NO3)2·6H2O/H2vab/Et3N in a 0.5:0.5:1:2 ratio in methanol. Variation in synthetic conditions was necessary to get the desired Co(II)-Ln(III) complexes. The Co(II)-Ln(III) assembly was synthesized from Ln(NO3)3·xH2O/Co(OAc)2·4H2O/H2vab/NaOMe in a 0.4:0.5:1:1 ratio in methanol. The isostructural Co(II)2Ln(III) complexes have a core structure with the general formula [Co2Ln(Hvab)4(NO3)](NO3)2·MeOH·H2O, (where H2vab = 2-[(2-hydroxymethyl-phenylimino)-methyl]-6-methoxy-phenol) with simultaneous crystallization of Co(II)7 complex in each reaction. The magnetic investigation of these complexes reveals that both homometallic complexes and four Co(II)-Ln(III) complexes (except Co(II)-Nd(III)) display behavior characteristic of single molecule magnets.

  20. Syntheses, structures, and magnetic properties of acetato- and diphenolato-bridged 3d-4f binuclear complexes [M(3-MeOsaltn)(MeOH)x(ac)Ln(hfac)2] (M = Zn(II), Cu(II), Ni(II), Co(II); Ln = La(III), Gd(III), Tb(III), Dy(III); 3-MeOsaltn = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato; ac = acetato; hfac = hexafluoroacetylacetonato; x = 0 or 1).

    Science.gov (United States)

    Towatari, Masaaki; Nishi, Koshiro; Fujinami, Takeshi; Matsumoto, Naohide; Sunatsuki, Yukinari; Kojima, Masaaki; Mochida, Naotaka; Ishida, Takayuki; Re, Nazzareno; Mrozinski, Jerzy

    2013-05-20

    A series of 3d-4f binuclear complexes, [M(3-MeOsaltn)(MeOH)x(ac)Ln(hfac)2] (x = 0 for M = Cu(II), Zn(II); x = 1 for M = Co(II), Ni(II); Ln = Gd(III), Tb(III), Dy(III), La(III)), have been synthesized and characterized, where 3-MeOsaltn, ac, and hfac denote N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato, acetato, and hexafluoroacetylacetonato, respectively. The X-ray analyses demonstrated that all the complexes have an acetato- and diphenolato-bridged M(II)-Ln(III) binuclear structure. The Cu(II)-Ln(III) and Zn(II)-Ln(III) complexes are crystallized in an isomorphous triclinic space group P1, where the Cu(II) or Zn(II) ion has square pyramidal coordination geometry with N2O2 donor atoms of 3-MeOsaltn at the equatorial coordination sites and one oxygen atom of the bridging acetato ion at the axial site. The Co(II)-Ln(III) and Ni(II)-Ln(III) complexes are crystallized in an isomorphous monoclinic space group P2(1)/c, where the Co(II) or Ni(II) ion at the high-spin state has an octahedral coordination environment with N2O2 donor atoms of 3-MeOsaltn at the equatorial sites, and one oxygen atom of the bridged acetato and a methanol oxygen atom at the two axial sites. Each Ln(III) ion for all the complexes is coordinated by four oxygen atoms of two phenolato and two methoxy oxygen atoms of "ligand-complex" M(3-MeOsaltn), four oxygen atoms of two hfac(-), and one oxygen atom of the bridging acetato ion; thus, the coordination number is nine. The temperature dependent magnetic susceptibilities from 1.9 to 300 K and the field-dependent magnetization up to 5 T at 1.9 K were measured. Due to the important orbital contributions of the Ln(III) (Tb(III), Dy(III)) and to a lesser extent the M(II) (Ni(II), Co(II)) components, the magnetic interaction between M(II) and Ln(III) ions were investigated by an empirical approach based on a comparison of the magnetic properties of the M(II)-Ln(III), Zn(II)-Ln(III), and M(II)-La(III) complexes. The differences of χ(M)T and M

  1. Yb-doped Gd2O2CO3: Structure, microstructure, thermal and magnetic behaviour

    Science.gov (United States)

    Artini, Cristina; Locardi, Federico; Pani, Marcella; Nelli, Ilaria; Caglieris, Federico; Masini, Roberto; Plaisier, Jasper Rikkert; Costa, Giorgio Andrea

    2017-04-01

    Structural and microstructural features, as well as thermal and magnetic properties of Yb-doped Gd2O2CO3, were investigated with the aim to clarify the location and the oxidation state of Yb within the structure, and its role in driving the extent of the (Gd1-xYbx)2O2CO3 solid solution. Yb is found in the 3+ oxidation state and it enters the structure only at the rare earth atomic site; the solubility limit results to be located in the close vicinity of x=0.25, and thermal analyses reveal a linear decrease of the decomposition temperature with increasing the Yb amount, in agreement with literature data. The structural analysis allows to exclude long-range clusterization of Yb and Gd, since both rare earths randomly distribute over the 4f atomic position, but relying on the results of the microstructural analysis, the presence of compositional inhomogenities at the local scale cannot be excluded. Not all the structural forms are documented for the pure rare earth dioxycarbonates [1]; in particular, while form I exists for each lanthanide ion, form II is stable only for the largest ones (from La to Dy); moreover, even if II-Ho2O2CO3 (rHo3+ CN8=1.015 Å [6]) is not reported to be stable, the existence of II-Y2O2CO3 (rY3+ CN8=1.019 Å [6]) has been claimed [7]. Based on the described evidence, the stability of hexagonal Yb-doped Gd2O2CO3 is not expected along the whole compositional range. As a general remark, not all the rare earth mixed dioxycarbonates exist: (Ce, Gd)2O2CO3, for instance, could not be obtained at any composition [8]; moreover, all the structural forms can be observed only in some mixed systems, such as for example (Gd, Nd)2O2CO3, by varying temperature and tuning the composition [9]. Rare earth dioxycarbonates are studied mainly for their CO2 sensing properties [10,11], and for their emission when properly doped with a luminescent lanthanide ion [12-17]. Recently, a study of this research group [18] revealed in Gd2O2CO3:4% Yb a phenomenon of

  2. Investigation of production routes for the 161Ho Auger-electron emitting radiolanthanide, a candidate for therapy

    CERN Document Server

    Tárkányi, F; Hermanne, A; Takács, S; Ignatyuk, A V

    2013-01-01

    The radiolanthanide 161Ho (2.48 h) is a promising Auger-electron emitter for internal radiotherapy that can be produced with particle accelerators. The excitation functions of the natDy(p,xn)161Ho and natDy(d,x)161Ho reactions were measured up to 40 and 50 MeV respectively by using the stacked foil activation method and gamma-ray spectrometry. The experimental data were compared with results of the TALYS code available in the TENDL 2011 library [1]. The main parameters of different production routes are discussed.

  3. 94 {beta}-Decay Half-Lives of Neutron-Rich 55Cs to 67Ho: Experimental Feedback and Evaluation of the r-Process Rare-Earth Peak Formation

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.; Nishimura, S.; Lorusso, G.; Moller, P; Ideguchi, E; Regan, P. H.; Simpson, G. S.; Soderstrom, P. -A.; Walker, P. M.; Watanabe, H.; Kondev, F. G.

    2017-02-17

    The β-decay half-lives of 94 neutron-rich nuclei 144$-$151Cs, 146$-$154Ba, 148$-$156La, 150$-$158Ce, 153$-$160Pr, 156$-$162Nd, 159$-$163Pm, 160$-$166Sm, 161$-$168Eu, 165$-$170Gd, 166$-$172Tb, 169$-$173Dy, 172$-$175Ho, and two isomeric states 174mEr, 172mDy were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of β-decay half-lives are observed at neutron-number N = 97 for 58Ce, 59Pr, 60Nd, and 62Sm, and N = 105 for 63Eu, 64Gd, 65Tb, and 66Dy. Lastly, features in the data mirror the interplay between pairing effects and microscopic structure. r-process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system

  4. Dy3Al5O12磁热性质研究∗%Study on the magnetic and magneto caloric effects of Dy3Al5O12

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The crystal field (CF)- and external magnetic field- split ground state of Dy3+ in Dy3Al5O12 (DyAG) has been calculated based on the quantum theory in this paper. The eight CF-split levels are obtained, which are all twofold degenerates and are removed by the external magnetic field. On the basis of the results, the magnetic moments and the magnetic entropy changes of DyAG are calculated in the temperature range of 3 < T < 42 K and the magnetic field range of 0DyAG have contribution to the average magnetic moment and have an important impact on the magnetic anisotropy of the crystal. In addition, the study indicates that the exchange interaction between the magnetic ions in DyAG is so weak that it may be neglected. However, distinct from DyAG, the exchange interaction between the rare-earth ions in Gd3Ga5O12(GdGG) is stronger at low temperatures and dependent on the temperature and external magnetic field. Besides, the variation of the adiabatic temperature change ∆T with T is theoretically anticipated and the anticipated results are comparied with that of GdGG. It is found that the maximum adiabatic temperature change ∆T of DyAG is 1.27 times larger than that of GdGG when T = 11 K and H e = 1 T. However, it changes to 1.15 times that of GdGG when T =16 K and H e =2 T. There are differences between the refrigerative properties of DyAG and GdGG when they are in different external magnetic fields and different temperature regions. At low temperature s(T < 10 K), the DyAG is a good magnetic refrigerative material in the lower external magnetic field. However, When H e is higher, GdGG is a good selection. This study is helpful to select suitable materials for the magnetic refrigeration technology.

  5. Magnetic properties of the RCo {sub x}Ge{sub 2} (R = Gd-Er) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Baran, S. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland); Henkel, F. [BENSC, Hahn-Meitner Institut, Glienicker Strasse 100, D-14109 Berlin-Wannsee (Germany); Kaczorowski, D. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Hernandez-Velasco, J. [BENSC, Hahn-Meitner Institut, Glienicker Strasse 100, D-14109 Berlin-Wannsee (Germany); Penc, B. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland); Stuesser, N. [BENSC, Hahn-Meitner Institut, Glienicker Strasse 100, D-14109 Berlin-Wannsee (Germany); Szytula, A. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland)]. E-mail: szytula@if.uj.edu.pl; Wawrzynska, E. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland)

    2006-05-18

    Magnetization, magnetic susceptibility, X-ray and neutron diffraction measurements down to 1.5 K were performed on polycrystalline RCo {sub x}Ge{sub 2} (R Gd-Er) samples, in which x = 0.4-0.5. All of them crystallize in the orthorhombic structure of the CeNiSi{sub 2}-type. The compounds were found to order antiferromagnetically at low temperatures except for the Tb and Dy samples, in which no magnetic contributions were observed in the neutron diffraction patterns recorded at 1.5 K although transitions are visible in the temperature dependences of the magnetic susceptibility of these compounds. In the case of HoCo{sub 0.4}Ge{sub 2} magnetic order appearing below the Neel temperature of 8 K is described by the propagation vector k = (1/2, 1/2, 0) and for the ErCo {sub x}Ge{sub 2} compounds at 1.5 K the structure is described by k = (k {sub x}, k {sub x}, 0). The value of the k {sub x} component depends on the concentration x.

  6. LiDy(PO34

    Directory of Open Access Journals (Sweden)

    Fathia Chehimi-Moumen

    2008-07-01

    Full Text Available Single crystals of lithium dysprosium polyphosphate, LiDy(PO34, were prepared by the flux method. The atomic arrangement is built up by infinite (PO3n chains extending along the b axis. Dy3+ and Li+ cations alternate in the middle of four such chains, with Dy...Li distances of 3.54 (1 and 3.48 (1 Å. The DyO8 dodecahedra and LiO4 tetrahedra deviate significantly from the ideal geometry. Both Dy and Li occupy special positions (Wyckoff position 4e, site symmetry 2.

  7. Separation and Recycling for Rare Earth Elements by Homogeneous Liquid-Liquid Extraction (HoLLE Using a pH-Responsive Fluorine-Based Surfactant

    Directory of Open Access Journals (Sweden)

    Shotaro Saito

    2015-08-01

    Full Text Available A selective separation and recycling system for metal ions was developed by homogeneous liquid-liquid extraction (HoLLE using a fluorosurfactant. Sixty-two different elemental ions (e.g., Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, La, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Re, Rh, Ru, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tl, Tm, V, W, Y, Yb, Zn, and Zr were examined. By changing pH from a neutral or alkaline solution (pH ≥ 6.5 to that of an acidic solution (pH < 4.0, gallium, zirconium, palladium, silver, platinum, and rare earth elements were extracted at >90% efficiency into a sedimented Zonyl FSA® (CF3(CF2n(CH22S(CH22COOH, n = 6–8 liquid phase. Moreover, all rare earth elements were obtained with superior extraction and stripping percentages. In the recycling of rare earth elements, the sedimented phase was maintained using a filter along with a mixed solution of THF and 1 M sodium hydroxide aqueous solution. The Zonyl FSA® was filtrated and the rare earth elements were recovered on the filter as a hydroxide. Furthermore, the filtrated Zonyl FSA was reusable by conditioning the subject pH.

  8. Development of bulk metallic glasses based on the Dy-Al binary eutectic composition

    Institute of Scientific and Technical Information of China (English)

    LUO Lin; TIAN Rui; XIAO Xueshan

    2008-01-01

    A series of dysprosium-based ternary, quadruple, and quintuple bulk metallic glasses (BMGs) based on Dy-Al binary eutectic compo-sition were obtained with the partial substitution of Co, Gd, and Ni elements, for dysprosium. The results showed that the Dy31Gd25Co20Al24 alloy, which had the best glass forming ability (GFA), could be cast into an amorphous rod with a diameter of 5 mm. The GFA of alloys was evaluated on the basis of the supercooled liquid region width, γ parameter, the formation enthalpy, and the equivalent electronegativity difference of amor-phous alloys. It was found that the eutectic composition was closely correlated with the GFA of the Dy-based BMGs.

  9. Magnetization and transport properties of single crystalline RPd2P2 (R=Y, La-Nd, Sm-Ho, Yb)

    Science.gov (United States)

    Drachuck, Gil; Böhmer, Anna E.; Bud'ko, Sergey L.; Canfield, Paul C.

    2016-11-01

    Single crystals of RPd2P2 (R=Y, La-Nd, Sm-Ho, Yb) were grown out of a high temperature solution rich in Pd and P and characterized by room-temperature powder X-ray diffraction, anisotropic temperature- and field-dependent magnetization and temperature-dependent in-plane resistivity measurements. In this series, YPd2P2 and LaPd2P2 YbPd2P2 (with Yb2+) are non-local-moment bearing. Furthermore, YPd2P2 and LaPd2P2 are found to be superconducting with Tc ≃ 0.75 and 0.96 K respectively. CePd2P2 and PrPd2P2 magnetically order at low temperature with a ferromagnetic component along the crystallographic c-axis. The rest of the series manifest low temperature antiferromagnetic ordering. EuPd2P2 has Eu2+ ions and both EuPd2P2 and GdPd2P2 have isotropic paramagnetic susceptibilities consistent with L=0 and J = S = 7/2 and exhibit multiple magnetic transitions. For R=Eu-Dy, there are multiple, T > 1.8 K transitions in zero applied magnetic field and for R=Nd, Eu, Gd, Tb, and Dy there are clear metamagnetic transitions at T=2.0 K for H < 55 kOe. Strong anisotropies arising mostly from crystal electric field (CEF) effects were observed for most magnetic rare earths with L ≠ 0. The experimentally estimated CEF parameters B20 were calculated from the anisotropic paramagnetic θab and θc values and compared to theoretical trends across the rare earth series. The ordering temperatures as well as the polycrystalline averaged paramagnetic Curie-Weiss temperature, θave, were extracted from magnetization and resistivity measurements, and compared to the de-Gennes factor.

  10. The magnetostriction of Tb, Dy and Ho revisited

    Energy Technology Data Exchange (ETDEWEB)

    Benito, L; Arnaudas, J I; Ciria, M; Fuente, C de la; Moral, A del [Departamento de Magnetismo de Solidos, Departamento de FIsica de la Materia Condensada-ICMA, Universidad de Zaragoza-CSIC, 50071 Zaragoza (Spain)

    2004-10-06

    In this paper we present re-analyses of magnetostriction measurements earlier performed in terbium, dysprosium and holmium single crystals. In the framework of the standard theory of single-ion crystal-electric-field and two-ion exchange magnetostrictions, we explain the thermal variation of the anisotropic saturation magnetostriction within the basal plane by considering high-order terms in the magnetoelastic energy. Using complementary basal-plane magnetic anisotropy measurements, we have been able to obtain the second- and fourth-order magnetoelastic coupling parameters associated with the orthorhombic distortion of the hexagonal plane for the above-mentioned three heavy rare earths.

  11. Fabrication, magnetostriction properties and applications of Tb-Dy-Fe alloys: a review

    Directory of Open Access Journals (Sweden)

    Nai-juan Wang

    2016-03-01

    Full Text Available As an excellent giant-magnetostrictive material, Tb-Dy-Fe alloys (based on Tb0.27-0.30Dy0.73-0.70Fe1.9-2 Laves compound can be applied in many engineering fields, such as sonar transducer systems, sensors, and micro-actuators. However, the cost of the rare earth elements Tb and Dy is too high to be widely applied for the materials. Nowadays, there are two different ways to substitute for these alloying elements. One is to partially replace Tb or Dy by cheaper rare earth elements, such as Pr, Nd, Sm and Ho; and the other is to use non-rare earth elements, such as Co, Al, Mn, Si, Ce, B, Be and C, to substitute Fe to form single MgCu2-type Laves phase and a certain amount of Re-rich phase, which can reduce the brittleness and improve the corrosion resistance of the alloy. This paper systemically introduces the development, the fabrication methods and the corresponding preferred growth directions of Tb-Dy-Fe alloys. In addition, the effects of alloying elements and heat treatment on magnetostrictive and mechanical properties of Tb-Dy-Fe alloys are also reviewed, respectively. Finally, some possible applications of Tb-Dy-Fe alloys are presented.

  12. Neutron scattering study on R{sub 2}PdSi{sub 3} (R=Ho,Er,Tm) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Fei

    2010-12-14

    Previous studies on the family of inter-metallic rare-earth compounds R{sub 2}PdSi{sub 3} revealed multifaceted magnetic properties, for instance, spin-glass like behavior. Experimental observations include: Signs of a crystallographic superstructure, complicated magnetic structures both in zero field and in applied magnetic fields as well as a generic phase in applied fields for compounds in the series with the heavy rare-earths R=Gd, Tb, Dy, Ho, Er and Tm. This thesis expands the studies on the magnetic properties of R{sub 2}PdSi{sub 3} employing mainly neutron scattering on single crystals with the focus on the compounds with R=Ho, Er and Tm. A detailed analysis of the crystallographic superstructure using modulation wave approach and group theory is presented. The resulting structure implies the existence of two different rare-earth sites with reduced symmetry and an arrangement of the different sites according to sequences as determined by the superstructure. It is shown that the reduced symmetry of the rare-earth sites is explicitly observed in the energy spectra of inelastic neutron scattering. The results on the magnetic structures and excitations are shown and discussed in the framework of the superstructure model. Specifically the generic phase in applied fields is interpreted as a direct consequence of the crystallographic superstructure. It is rather unusual that a crystallographic superstructure is playing such a decisive, and through the field dependence also tunable role in determining the magnetic properties as observed in R{sub 2}PdSi{sub 3}. The mediating interactions between the crystallographic part and the magnetic part of the system are discussed. (orig.)

  13. Benzoxazole-based heterometallic dodecanuclear complex [Dy(III)4Cu(II)8] with single-molecule-magnet behavior.

    Science.gov (United States)

    Iasco, Olga; Novitchi, Ghenadie; Jeanneau, Erwann; Wernsdorfer, Wolfgang; Luneau, Dominique

    2011-08-15

    Three Cu-Ln (Ln = Dy, Gd, Y) dodecanuclear clusters assembled by a novel ligand of the benzoxazole type are reported. The dysprosium cluster exhibits a frequency dependence of the alternating-current susceptibility and hysteresis loop at low temperature, indicating single-molecule-magnet behavior.

  14. Two hexagonal series of lanthanoid(III) oxide fluoride selenides.: M{sub 6}O{sub 2}F{sub 8}Se{sub 3} (M = La - Nd) and M{sub 2}OF{sub 2}Se (M = Nd, Sm, Gd - Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Dirk D.; Grossholz, Hagen; Wolf, Sarah; Schleid, Thomas [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Janka, Oliver [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Mueller, Alexander C. [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Institut fuer Textilchemie und Chemiefasern, Denkendorf (Germany)

    2015-09-15

    Two hexagonal series of lanthanoid(III) oxide fluoride selenides with similar structure types can be obtained by the reaction of the components MF{sub 3}, M{sub 2}O{sub 3}, M, and Se in sealed niobium tubes at 850 C using CsI as fluxing agent. The compounds with the lighter and larger representatives (M = La - Nd) occur with the formula M{sub 6}O{sub 2}F{sub 8}Se{sub 3}, whereas with the heavier and smaller ones (M = Nd, Sm, Gd - Ho) their composition is M{sub 2}OF{sub 2}Se. For both systems single-crystal determinations were used in all cases. The compounds crystallize in the hexagonal crystal system (space group: P6{sub 3}/m) with lattice parameters of a = 1394-1331 pm and c = 403-372 pm (Z = 2 for M{sub 6}O{sub 2}F{sub 8}Se{sub 3} and Z = 6 for M{sub 2}OF{sub 2}Se). The (M1){sup 3+} cations show different square antiprismatic coordination spheres with or without an extra capping fluoride anion. All (M2){sup 3+} cations exhibit a ninefold coordination environment shaped as tricapped trigonal prism. In both structure types the Se{sup 2-} anions are sixfold coordinated as trigonal prisms of M{sup 3+} cations, being first condensed by edges to generate trimeric units and then via faces to form strands running along [001]. The light anions reside either in threefold triangular or in fourfold tetrahedral cationic coordination. For charge compensation, both structures have to contain a certain amount of oxide besides fluoride anions. Since F{sup -} and O{sup 2-} can not be distinguished by X-ray diffraction, bond-valence calculations were used to address the problem of their adjunction to the available crystallographic sites. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Crystal growth, structure, and physical properties of Ln(Cu,Al)12 (Ln = Y, Ce, Pr, Sm, and Yb) and Ln(Cu, Ga)12 (Ln = Y, Gd-Er, and Yb).

    Science.gov (United States)

    Drake, Brenton L; Capan, C; Cho, Jung Young; Nambu, Y; Kuga, K; Xiong, Y M; Karki, A B; Nakatsuji, S; Adams, P W; Young, D P; Chan, Julia Y

    2010-02-17

    Single crystals of Ln(Cu,Al)12 and Ln(Cu,Ga)12 compounds (Ln = Y, Ce-Nd, Sm, Gd-Ho, and Yb for Al and Ln = Y, Gd-Er, Yb for Ga) have been grown by flux-growth methods and characterized by means of single-crystal x-ray diffraction, complemented with microprobe analysis, magnetic susceptibility, resistivity and heat capacity measurements. Ln(Cu,Ga)12 and Ln(Cu,Al)12 of the ThMn12 structure type crystallize in the tetragonal I4/mmm space group with lattice parameters a approximately 8.59 Å and c approximately 5.15 Å and a approximately 8.75 Å and c approximately 5.13 Å for Ga and Al containing compounds, respectively. For aluminium containing compounds, magnetic susceptibility data show Curie-Weiss paramagnetism in the Ce and Pr analogues down to 50 K with no magnetic ordering down to 3 K, whereas the Yb analogue shows a temperature-independent Pauli paramagnetism. Sm(Cu,Al)12 orders antiferromagnetically at T(N)approximately 5 K and interestingly exhibits Curie-Weiss behaviour down to 10 K with no Van Vleck contribution to the susceptibility. Specific heat data show that Ce(Cu,Al)12 is a heavy fermion antiferromagnet with T(N) approximately 2 K and with an electronic specific heat coefficient γ0 as large as 390 mJ K2 mol(-1). In addition, this is the first report of Pr(Cu,Al)12 and Sm(Cu,Al)12 showing an enhanced mass (approximately 80 and 120 mJ K(2) mol(-1)). For Ga containing analogues, magnetic susceptibility data also show the expected Curie-Weiss behaviour from Gd to Er, with the Yb analogue being once again a Pauli paramagnet. The antiferromagnetic transition temperatures range over 12.5, 13.5, 6.7, and 3.4 K for Gd, Tb, Dy, and Er. Metallic behaviour is observed down to 3 K for all Ga and Al analogues. A large positive magnetoresistance up to 150% at 9 T is also observed for Dy(Cu,Ga)12. The structure, magnetic, and transport properties of these compounds will be discussed.

  16. Neutron diffraction studies of the magnetic structure of Ho{sub 3}Pd{sub 4}Ge{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzynska, E.; Penc, B.; Hernandez-Velasco, J.; Szytula, A.; Zygmunt, A

    2003-02-17

    Ho{sub 3}Pd{sub 4}Ge{sub 4} crystallizes in the orthorhombic Gd{sub 6}Cu{sub 8}Ce{sub 8}-type of structure (space group Immm) in which the Ho atoms occupy two nonequivalent crystallographic positions: 2a and 4j. Neutron diffraction measurements indicate that the Ho moments in the 4j site below 6.7 K form a collinear antiferromagnetic structure with the magnetic moments parallel to the a axis, whereas the Ho moments in the 2a site below 5 K form a sine-wave modulated structure with the magnetic moments parallel to the c axis.

  17. Equiatomic compounds REIrMg (RE = Y, La-Nd, Sm, Gd-Tm) and RERhMg (RE = Y, Sm, Gd-Tm)

    Science.gov (United States)

    Stein, Sebastian; Heletta, Lukas; Pöttgen, Rainer

    2017-09-01

    The equiatomic intermetallic compounds REIrMg (RE = Y, La-Nd, Sm, Gd-Tm) and RERhMg (RE = Y, Sm, Gd-Tm) were synthesized from the elements in sealed niobium ampoules in a high-frequency furnace and characterized based on X-ray powder data. LaIrMg and CeIrMg crystallize with the orthorhombic LaNiAl type structure (Pnma), while all other compounds adopt the TiNiSi type. The structures of YRhMg, GdRh1.190(4)Mg0.810(4), DyRh1.126(5)Mg0.874(5), LaIrMg, NdIr1.033(2)Mg0.967(2) and ErIr1.059(3)Mg0.941(3) were refined from single-crystal X-ray diffractometer data. The striking structural motifs of these phases are tricapped trigonal prisms around the transition metal atoms formed by RE and Mg. The two structure types differ in the connectivity pattern of the trigonal prisms. The rhodium (iridium) atoms build up three-dimensional [RhMg] and [IrMg] networks in which cavities are filled by the rare earth atoms. Temperature dependent magnetic susceptibility measurements on X-ray pure samples of NdIrMg, SmRhMg, GdRhMg, TbRhMg and DyRhMg show Curie-Weiss paramagnetism of the trivalent rare earth ions and magnetic ordering at low temperatures: TC = 9.5 K for NdIrMg and Néel temperatures of 10.0, 16.7, 10.6 and 11.3 K for SmRhMg, GdRhMg, TbRhMg and DyRhMg. TbRhMg and DyRhMg exhibit field-induced spin reorientations (metamagnetism).

  18. VizieR Online Data Catalog: Laboratory transition probabilities for Gd II (Den Hartog+, 2006)

    Science.gov (United States)

    den Hartog, E. A.; Lawler, J. E.; Sneden, C.; Cowan, J. J.

    2008-05-01

    Radiative lifetimes, accurate to +/-5%, have been measured for 49 even-parity and 14 odd-parity levels of GdII using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 611 lines of Gd II. This work is the largest-scale laboratory study to date of GdII transition probabilities and the first using a high-performance Fourier transform spectrometer. This improved data set has been used to determine a new solar photospheric Gd abundance, log{epsilon}=1.11+/-0.03. Revised Gd abundances have also been derived for the r-process-rich metal-poor giant stars CS 22892-052, BD +17 3248, and HD 115444. The resulting Gd/Eu abundance ratios are in very good agreement with the solar system r-process ratio. We have employed the increasingly accurate stellar abundance determinations, resulting in large part from the more precise laboratory atomic data, to predict directly the solar system r-process elemental abundances for Gd, Sm, Ho, and Nd. Our analysis of the stellar data suggests slightly higher recommended values for the r-process contribution and total solar system values, consistent with the photospheric determinations, for the elements for Gd, Sm, and Ho. (1 data file).

  19. Implantation sites of Ce and Gd in diamond

    CERN Document Server

    Bharuth-Ram, K; Hofsäss, H C; Ronning, C; Dietrich, M

    2002-01-01

    The implantation sites of rare earth (RE) probes /sup 141/Ce (t/sub 1 /2/=32 d) and /sup 149/Gd (t/sub 1/2/=9.28 d) in diamond have been investigated using the emission channeling (EC) technique. Parent isotopes /sup 141/Cs and /sup 149/Dy were implanted into type IIa, diamond samples at an energy of 60 keV at the online isotope separator ISOLDE at CERN. /sup 141/Cs decays through the chain /sup 141/Cs-/sup 141/Ba-/sup 141/La-/sup 141/Ce-/sup 141/ Pr. EC measurements were made on the 102 keV conversion electrons emitted in the decay of /sup 141/Pr to its ground state. The decay of /sup 149 /Dy follows the chain /sup 149/Dy-/sup 149/Tb-/sup 149/Gd-/sup 149 /Eu-/sup 149/Sm. EC measurements were made on the 101 keV electrons emitted in the decay of /sup 149/Eu. Two-dimensional channeling patterns of the conversion electrons were obtained along and axial directions by raster scans with a Si surface barrier detector. Comparison of the observed patterns with simulated spectra show that in diamond 45-50% of the RE...

  20. The Dy-Zn phase diagram

    Science.gov (United States)

    Saccone, A.; Cardinale, A. M.; Delfino, S.; Ferro, R.

    2003-03-01

    The dysprosium-zinc phase diagram has been investigated over its entire composition range by using differential thermal analysis, (DTA) metallographic analysis, X-ray powder diffraction, and electron probe microanalysis (EPMA). Seven intermetallic phases have been found and their structures confirmed. DyZn, DyZn2, Dy13Zn58, and Dy2Zn17 melt congruently at 1095 °C, 1050 °C, 930 °C, and 930 °C, respectively. DyZn3, Dy3Zn11, and DyZn12 form through peritectic reactions at 895 °C, about 900 °C and 685 °C, respectively. Four eutectic reactions occur at 850 °C and 30.0 at pct Zn (between (Dy) and DyZn), 990 °C and 60.0 at pct Zn (between DyZn and DyZn2), 885 °C and 76.0 at pct Zn (between DyZn3 and Dy3Zn11), and 875 °C and 85.0 at pct Zn (involving Dy13Zn58 and Dy2Zn17). The Dy-rich end presents a catatectic equilibrium; a degenerate invariant effect has been found in the Zn-rich region. The phase equilibria of the Dy-Zn alloys are discussed and compared with those of the other known RE-Zn systems (RE=rare earth metal) in view of the regular change in the relative stabilities of the phases across the lanthanide series

  1. Properties of Dy 3+-doped PbWO 4 single crystal grown by modified Bridgman method

    Science.gov (United States)

    Huang, Yanlin; Zhu, Wenliang; Feng, Xiqi; Duan, Yong; Man, Zhenyong

    2003-01-01

    Undoped and Dy 3+-doped PbWO 4 single crystals were grown in the same condition by modified Bridgman method. Optical transmittance, X-ray excited luminescence, excitation and emission under UV light, thermoluminescence glow curves and X-ray pulsed excited decays were investigated on Dy 3+:PWO for the first time. Dy 3+-doping has a positive effect similar to that of rare-earth ions La 3+ and Gd 3+, such as improvement of transmittance in the wavelength region of scintillation emission (350-450 nm), compensation of trapping centers that is reflected in the thermoluminescence characteristics and suppression of slow decay component in luminescence kinetics. Analysis of luminescence spectra indicates that energy transfer could take place from the PbWO 4 host to the Dy 3+ ions, followed by characteristic emission line assigned to transition from 4F 9/2 of Dy 3+ ion to lower lying states on basis of the energy level scheme. A tentative concept of energy transfer mechanism is proposed in this paper.

  2. Optical Investigations of Rare-Earth Orthochromites. III. GdCrO3 and Summary of the R' Band in RCrO3

    Science.gov (United States)

    Kojima, Norimichi; Tsujikawa, Ikuji; Tsushima, Kuniro

    1985-12-01

    Optical absorption spectrum corresponding to the 4A2g→2Eg transition of Cr3+ in GdCrO3 was studied. The R' band was observed in the lower energy side of the R exciton band. The temperature and magnetic field dependences of the R' band imply that the R' band is the combined excitation of a Cr3+ exciton and a Gd3+ spin flip induced by the isotropic part of the Cr3+-Gd3+ exchange interaction. As the summary of the successive papers, the classification of the R' band in RCrO3(R=Yb, Tm, Er, No, Dy, Tb and Gd) was undertaken.

  3. Series of edge-sharing bi-triangle Ln4 clusters with a μ4-NO3- bridge: syntheses, structures, luminescence, and the SMM behavior of the Dy4 analogue.

    Science.gov (United States)

    Zou, Hua-Hong; Wang, Rong; Chen, Zi-Lu; Liu, Dong-Cheng; Liang, Fu-Pei

    2014-02-14

    A series of Ln4 clusters, [Ln4L2(μ3-OH)2(μ4-NO3)(NO3)4(OCH3)(H2O)]·xMeCN·yMeOH (Ln = Gd (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), L = 2-{[2-(2-hydroxy-ethoxy)-ethylimino]-methyl}-6-methoxyphenol), have been synthesized by the reaction of Ln(NO)3 and a Schiff-base ligand formed in situ. The six complexes display similar structures, with an overall metal core comprising two edge-sharing triangular Ln3 units linked by a μ4-NO3(-) bridge. The luminescence spectrum of complex 2 shows the characteristic emission of the Tb(III) ions. The magnetic susceptibility studies reveal that the Ln(III) ions are very weakly interacting in all six compounds. Frequency dependence of the ac-susceptibility was found for 3, suggesting a typical single-molecule magnet (SMM) behavior with an anisotropic barrier of 28 K.

  4. Series of isostructural planar lanthanide complexes [Ln(III)4(mu3-OH)2(mdeaH)2(piv)8] with single molecule magnet behavior for the Dy4 analogue.

    Science.gov (United States)

    Abbas, Ghulam; Lan, Yanhua; Kostakis, George E; Wernsdorfer, Wolfgang; Anson, Christopher E; Powell, Annie K

    2010-09-06

    A series of five isostructural tetranuclear lanthanide complexes of formula [Ln(4)(mu(3)-OH)(2)(mdeaH)(2)(piv)(8)], (mdeaH(2) = N-methyldiethanolamine; piv = pivalate; Ln = Tb (1), Dy (2), Ho (3), Er (4), and Tm (5)) have been synthesized and characterized. These clusters have a planar "butterfly" Ln(4) core. Magnetically, the Ln(III) ions are weakly coupled in all cases; the Dy(4) compound 2 shows Single Molecule Magnet (SMM) behavior.

  5. Scissors Mode of 162Dy Studied from Resonance Neutron Capture

    Directory of Open Access Journals (Sweden)

    Baramsai B.

    2015-01-01

    Full Text Available Multi-step cascade γ-ray spectra from the neutron capture at isolated resonances of 161Dy nucleus were measured at the LANSCE/DANCE time-of-flight facility in Los Alamos National Laboratory. The objectives of this experiment were to confirm and possibly extend the spin assignment of s-wave neutron resonances and get new information on photon strength functions with emphasis on the role of the M1 scissors mode vibration. The preliminary results show that the scissors mode plays a significant role in all transitions between accessible states of the studied nucleus. The photon strength functions describing well our data are compared to results from 3He-induced reactions, (n,γ experiments on Gd isotopes, and (γ,γ’ reactions.

  6. Scissors Mode of 162Dy Studied from Resonance Neutron Capture

    Science.gov (United States)

    Baramsai, B.; Bečvář, F.; Bredeweg, T. A.; Haight, R. C.; Jandel, M.; Kroll, J.; Krtička, M.; Mitchell, G. E.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Valenta, S.; Wilhelmy, J. B.

    2015-05-01

    Multi-step cascade γ-ray spectra from the neutron capture at isolated resonances of 161Dy nucleus were measured at the LANSCE/DANCE time-of-flight facility in Los Alamos National Laboratory. The objectives of this experiment were to confirm and possibly extend the spin assignment of s-wave neutron resonances and get new information on photon strength functions with emphasis on the role of the M1 scissors mode vibration. The preliminary results show that the scissors mode plays a significant role in all transitions between accessible states of the studied nucleus. The photon strength functions describing well our data are compared to results from 3He-induced reactions, (n,γ) experiments on Gd isotopes, and (γ,γ') reactions.

  7. Dy$^{3+}$-activated M$_2$SiO$_4$ (M $=$ Ba, Mg, Sr)-type phosphors

    Indian Academy of Sciences (India)

    ESRA ÖZTÜRK; ERKUL KARACAOGLU

    2017-02-01

    The alkaline orthosilicates of M$_2$SiO$_4$ (M $=$ Ba, Mg, Sr) activated with Dy$^{3+}$ and co-doped with Ho$^{3+}$ are prepared through conventional solid-state method, i.e., mixing and grinding of solid form precursors followedby high-temperature heat treatments of several hours in furnaces, generally under open atmosphere and investigated by X-ray diffraction (XRD) to get phase properties and photoluminescence (PL) analysis to get luminescenceproperties. The thermal behaviours of well-mixed samples were determined by differential thermal analysis (DTA)/thermogravimetry (TG). The PL spectra show that the 478 and 572nm maximum emission bands are attributed, respectively, to ${}^{4}$F$_{9/2}$ $\\to$ ${}^{6}$H$_{15/2}$ and ${}^{4}$F$_{9/2}$ $\\to$ ${}^{6}$H$_{13/2}$ transitions of Dy$^{3+}$ ions.

  8. Magnetic interactions in CuII-LnIII cyclic tetranuclear complexes: is it possible to explain the occurrence of SMM behavior in CuII-TbIII and CuII-DyIII complexes?

    Science.gov (United States)

    Hamamatsu, Takefumi; Yabe, Kazuya; Towatari, Masaaki; Osa, Shutaro; Matsumoto, Naohide; Re, Nazzareno; Pochaba, Andrzej; Mrozinski, Jerzy; Gallani, Jean-Louis; Barla, Alessandro; Imperia, Paolo; Paulsen, Carley; Kappler, Jean-Paul

    2007-05-28

    An extensive series of tetranuclear CuII2LnIII2 complexes [CuIILLnIII(hfac)2]2 (with LnIII being all lanthanide(III) ions except for the radioactive PmIII) has been prepared in order to investigate the nature of the CuII-LnIII magnetic interactions and to try to answer the following question: What makes the CuII2TbIII2 and CuII2DyIII2 complexes single molecule magnets while the other complexes are not? All the complexes within this series possess a similar cyclic tetranuclear structure, in which the CuII and LnIII ions are arrayed alternately via bridges of ligand complex (CuIIL). Regular SQUID magnetometry measurements have been performed on the series. The temperature-dependent magnetic susceptibilities from 2 to 300 K and the field-dependent magnetizations from 0 to 5 T at 2 K have been measured for the CuII2LnIII2 and NiII2LnIII2 complexes, with the NiII2LnIII2 complex containing diamagnetic NiII ions being used as a reference for the evaluation of the CuII-LnIII magnetic interactions. These measurements have revealed that the interactions between CuII and LnIII ions are very weakly antiferromagnetic if Ln=Ce, Nd, Sm, Yb, ferromagnetic if Ln=Gd, Tb, Dy, Ho, Er, Tm, and negligible if Ln=La, Eu, Pr, Lu. With the same goal of better understanding the evolution of the intramolecular magnetic interactions, X-ray magnetic circular dichroism (XMCD) has also been measured on CuII2TbIII2, CuII2DyIII2, and NiII2TbIII2 complexes, either at the L- and M-edges of the metal ions or at the K-edge of the N and O atoms. Last, the CuII2TbIII2 complex exhibiting SMM behavior has received a closer examination of its low temperature magnetic properties down to 0.1 K. These particular measurements have revealed the unusual very slow setting-up of a 3D order below 0.6 K.

  9. Superdeformation studies in {sup 150}Tb and {sup 153}Ho

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

    1995-08-01

    There are now over 40 superdeformed (SD) bands known in the A {approximately} 150 region and in most cases the properties of these bands are understood in terms of single-particle excitations in the absence of pairing. By continuing the search for new SD bands we hope to gain insight into (1) the ordering of the proton and neutron orbitals near the Fermi surface in the SD well, (2) the effects that the alignment of those orbitals has on the moments of inertia, and (3) the collective excitations in the SD well. For {sup 150}Tb, which is one proton and one neutron away from the SD doubly-magic nucleus {sup 152}Dy, it should be possible to study SD bands based on both proton and neutron hole excitations. By adding one proton to the {sup 152}Dy nucleus (i.e. {sup 153}Ho) proton excitations above the Z = 66 shell gap can be studied. These excitations are important as calculations suggested that the proton intruder orbital N = 7 might become occupied. Interactions between this orbital and a N = 5 level may result in softness towards octupole vibrations. High spin states in {sup 150}Th and {sup 153}Ho were populated using the {sup 124}Sn({sup 31}P,5n) and {sup 120}Sn({sup 37}Cl,4n) reactions, respectively. In both cases the early implementation phase of Gammasphere was used to detect the decay gamma rays and over 1 x 10{sup 9} triple and higher fold coincidence events were recorded. In {sup 150}Tb, the data analysis is complete and two new SD bands were identified. The fact that Im{sup (2)} moments of inertia are sensitive to the specific high-N intruder content of the SD bands was used to suggest configurations for the two new bands. A paper reporting these results is being prepared. For {sup 153}Ho, data analysis is still in its early stages.

  10. Study on Gd-Si-Ge Alloys Using Domestic Gd

    Institute of Scientific and Technical Information of China (English)

    吴卫; 卢定伟

    2004-01-01

    To evaluate the possibility of using Gd-Si-Ge alloys in magnetic refrigerators,samples of Gd-Si-Ge alloys were made of domestic Gd.The magnetocaloric effect of samples was estimated by magnetic entropy change (-ΔSm) calculated from M-H curves according to Maxwell relation.The first order phase transformation was destroyed due to the impurities in the commercial Gd,so that no giant magnetocaloric effect was found.The samples made of purified Gd exhibit first order phase transformation,and the -ΔSm is basically consistent with the published data of Ames laboratory,USA.This work proves that Gd-Si-Ge alloys made of domestic Gd can be utilized in magnetic refrigerators.

  11. Multicolor photoluminescence and energy transfer properties of dysprosium and europium-doped Gd{sub 2}O{sub 3} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yanxia; Liu, Guixia, E-mail: liuguixia22@163.com; Wang, Jinxian; Dong, Xiangting; Yu, Wensheng

    2015-11-15

    In this study, a series of Gd{sub 2}O{sub 3}: Ln{sup 3+} (Ln = Dy, Eu) submicrospheres were successfully prepared by a hydrothermal method and a subsequent higher temperature pyrolysis. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectrometer (EDS), photoluminescence (PL) spectra and vibrating sample magnetometer (VSM) were utilized to characterize the as-prepared samples. The precursor sample thoroughly decomposed into Gd{sub 2}O{sub 3} submicrospheres with a diameter of about 550 nm after calcination. Under UV excitation, the samples exhibit multicolor emissions including yellow-green, yellow, red as well as white, moreover, the Dy{sup 3+} ions acted as donors can transfer the energy to Eu{sup 3+} served as acceptors in Gd{sub 2}O{sub 3}: Dy{sup 3+}, Eu{sup 3+} system. The interaction between Dy{sup 3+} ions and Eu{sup 3+} ions is verified to be phonon-assisted electric quadrupole–quadrupole interaction. Multicolor luminescence including white light emission can be obtained through varying the content of Eu{sup 3+} or adopting different excitation wavelengths in Dy{sup 3+} and Eu{sup 3+} co-doped Gd{sub 2}O{sub 3} system. The energy transfer efficiency reaches 88.2% when the doped concentration of Eu{sup 3+} is 0.035. The CIE chromaticity diagram directly reveals the variability of the hue of the as-prepared samples. Besides, the as-prepared samples exhibit paramagnetic properties at room temperature. This type of color-tunable luminescence phosphors has promising applications in the fields of photoelectronic devices and biomedical science. - Graphical abstract: Tunable multicolor emissions and energy transfer properties of lanthanides (Ln{sup 3+}, Ln{sup 3+} = Dy{sup 3+}, Eu{sup 3+}) doped cubic Gd{sub 2}O{sub 3} submicrospheres prepared by hydrothermal method and a subsequent calcination. - Highlights: • The as-prepared samples can exhibit multicolor emissions.

  12. The metallofullerene field-induced single-ion magnet HoSc2 N@C80.

    Science.gov (United States)

    Dreiser, Jan; Westerström, Rasmus; Zhang, Yang; Popov, Alexey A; Dunsch, Lothar; Krämer, Karl; Liu, Shi-Xia; Decurtins, Silvio; Greber, Thomas

    2014-10-13

    The low-temperature magnetic properties of the endohedral metallofullerene HoSc2 N@C80 have been studied by superconducting quantum interference device (SQUID) magnetometry. Alternating current (ac) susceptibility measurements reveal that this molecule exhibits slow relaxation of magnetization in a small applied field with timescales in the order of milliseconds. The equilibrium magnetic properties of HoSc2 N@C80 indicate strong magnetic anisotropy. The large differences in magnetization relaxation times between the present compound and the previously investigated DySc2 N@C80 are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Smooth transition between SMM and SCM-type slow relaxing dynamics for a 1-D assemblage of {Dy(nitronyl nitroxide)2} units.

    Science.gov (United States)

    Liu, Ruina; Li, Licun; Wang, Xiaoling; Yang, Peipei; Wang, Chao; Liao, Daizheng; Sutter, Jean-Pascal

    2010-04-21

    A model example for size effects on the dynamic susceptibility behavior is provided by the chain compound [{Dy(hfac)(3)NitPhIm(2)}Dy(hfac)(3)] (NitPhIm = 2-[4-(1-imidazole)phenyl]nitronyl nitroxide radical). The Arrhenius plot reveals two relaxation regimes attributed to SMM (Delta = 17.1 K and tau(0) = 17.5 x 10(-6) s) and SCM (Delta = 82.7 K and tau(0) = 8.8 x 10(-8) s) behaviors. The ferromagnetic exchange among the spin carriers has been established for the corresponding Gd derivative.

  14. ISOMER-SELECTED DECAY OF THE GDR IN DY-156

    NARCIS (Netherlands)

    VANSCHAGEN, JPS; HARAKEH, MN; HESSELINK, WHA; NOORMAN, RF

    1995-01-01

    The strength distribution of high-energy gamma-rays emitted in the statistical decay of the 156Dy compound nucleus, with E* = 92.5 MeV, has been measured inclusively and for selected decay pathways in which isomers in 149Dy, 151Dy and 152Dy were populated. For both spectra a deformation \\beta\\ = 0.3

  15. Epitaxial stabilization of artificial hexagonal GdMnO3 thin films and their magnetic properties

    Science.gov (United States)

    Lee, D.; Lee, J.-H.; Murugavel, P.; Jang, S. Y.; Noh, T. W.; Jo, Y.; Jung, M.-H.; Ko, Y.-D.; Chung, J.-S.

    2007-04-01

    The authors investigated the role of oxygen partial pressure on the epitaxial growth of an artificial hexagonal GdMnO3 phase, which should exist in an orthorhombic structure in bulk. The hexagonal GdMnO3 film showed diverse, but obvious, magnetic phase transitions with highly enhanced ferromagnetic properties. Its remnant magnetization at 4.2K is higher than those of other hexagonal RMnO3 (R =Ho, Er, and Yb) compounds, and the Curie temperature increases by around 25K. The results demonstrate that the epitaxial stabilization technique is a promising method for fabricating an artificial material with enhanced magnetic properties.

  16. Synthesis of ZnO:Dy Nanopowder and Photoluminescence of Dy3+ in ZnO

    Institute of Scientific and Technical Information of China (English)

    Zhang Linli; Guo Changxin; Zhao Junjing; Hu Juntao

    2005-01-01

    A type of dysprosium-doped ZnO (ZnO:Dy) nanopowder was synthesized by high temperature calcinations. XRD was used to analyze the structure. Photoluminescence spectra were used to study the optical characteristic. PL of ZnO:Dy shows two different spectra which are broad band resulted from the defect of Dy in ZnO and sharp lines from the 4f→4f transition of isolated Dy3+ luminescence center. The emission and excitation spectra depend on the excitation wavelength and the concentration of Dy3+. The broad bands with peaks at 600 and 760 nm are attributed to the recombination from an electron of the defect Dy in ZnO to a hole in VB.

  17. DySectAPI: Scalable Prescriptive Debugging

    DEFF Research Database (Denmark)

    Jensen, Nicklas Bo; Karlsson, Sven; Quarfot Nielsen, Niklas;

    We present the DySectAPI, a tool that allow users to construct probe trees for automatic, event-driven debugging at scale. The traditional, interactive debugging model, whereby users manually step through and inspect their application, does not scale well even for current supercomputers. While...... lightweight debugging models scale well, they can currently only debug a subset of bug classes. DySectAPI fills the gap between these two approaches with a novel user-guided approach. Using both experimental results and analytical modeling we show how DySectAPI scales and can run with a low overhead...

  18. First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of $^{163}$Ho

    CERN Document Server

    Ranitzsch, P. C. -O.; Wegner, M.; Kempf, S.; Fleischmann, A.; Enss, C.; Gastaldo, L.; Herlert, A.; Johnston, K.

    2014-01-01

    The isotope $^{163}$Ho undergoes an electron capture process with a recommended value for the energy available to the decay, $Q_{\\rm EC}$, of about 2.5 keV. According to the present knowledge, this is the lowest $Q_{\\rm EC}$ value for electron capture processes. Because of that, $^{163}$Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the $^{163}$Dy daughter atom upon the capture of an electron from the 5s shell in $^{163}$Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the $^{163}$Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of $^{163}$Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we dis...

  19. Magnetocaloric properties of rare-earth substituted DyCrO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    McDannald, A. [Material Science and Engineering Department, University of Connecticut, Storrs, Connecticut 06269 (United States); Jain, M., E-mail: menka.jain@uconn.edu [Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States)

    2015-07-28

    Recently, there has been a focus on the need for efficient refrigeration technology without the use of expensive or harmful working fluids, especially at temperatures below 30 K. Solid state refrigeration, based on the magnetocaloric effect, provides a possible solution to this problem. The rare-earth chromites (RCrO{sub 3}), especially DyCrO{sub 3}, with its large magnetic moment dysprosium ion, are potential candidates for such an application. The Dy{sup 3+} ordering transition at low temperatures (<10 K) likely causes a large magnetocaloric response in this material. This study investigates the possibility of tuning the magnetocaloric properties through the use of rare-earth substitution. Both Y{sup 3+} and Ho{sup 3+} substitutions were found to decrease the magnetocaloric response by disrupting the R{sup 3+} ordering. Whereas Er{sup 3+} substitution was found to increase the magnetocaloric response, likely due to an increase in the R{sup 3+} ordering temperature. The large magnetocaloric entropy change of Er{sup 3+} substituted DyCrO{sub 3} (10.92 J/kg K with a relative cooling power of 237 J/kg at 40 kOe and 5 K) indicates that this material system is well suited for low temperature (<30 K) solid state refrigeration applications.

  20. Crystal structure of Tb5Ni2In4, and magnetic properties of Dy5Ni2In4

    Energy Technology Data Exchange (ETDEWEB)

    Provino, A.; Mudryk, Y.; Paudyal, D.; Smetana, V.; Manfrinetti, P.; Pecharsky, V.K.; Gschneidner Jr, Karl; Corbett, J.D.

    2012-02-27

    The crystal structure of the R5Ni2In4 intermetallic compounds was earlier reported for R Ho, Er, Tm, and Lu (Lu5Ni2In4-type, oP22, Pbam); more recently the isostructural phases Dy5Ni2In4 and Sc5Ni2In4 have also been identified. Three inequivalent crystallographic sites are occupied by the R atoms in these compounds. We have synthesized and characterized Dy5Ni2In4 and the two new isotypic compounds Tb5Ni2In4 and Y5Ni2In4. So far, none of the physical properties have been reported on any of these phases; in this article we report on the physical properties of the Dy5Ni2In4 and the crystal structure of Tb5Ni2In4 and Y5Ni2In4 compounds. Measurements of the magnetic properties performed on Dy5Ni2In4 show a ferromagnetic-like ordering with a T-C approximate to 105 K, followed by multiple magnetic orderings at lower temperatures. The fit of the inverse susceptibility in the paramagnetic state follows the Curie-Weiss law, where mu(eff). - 10.3 mu(B)/Dy-atom (close to theoretical value of 10.64 mu(B) for the free ion Dy3+) and a positive paramagnetic Curie temperature theta(p) - 58 K. Ni atoms are most likely to be nonmagnetic. The heat capacity also shows three peaks: a large one at 103K and two weaker at 12 and 8 K, respectively; the in-field heat capacity data corroborate these results, suggesting ferromagnetic and antiferromagnetic orderings at the temperature of 103 and 12 K, respectively. Low temperature x-ray diffraction has shown that the compound does not undergo any structural change down to 5K. (C) 2012 American Institute of Physics.

  1. NdHO, a novel oxyhydride

    DEFF Research Database (Denmark)

    Widerøe, Marius; Fjellvåg, Helmer; Norby, Truls

    2011-01-01

    A new metal oxyhydride; neodymium oxyhydride, NdHO, has been synthesized from a reactant mixture of metal hydride (CaH2 or NdH3) and neodymium oxide(Nd2O3). The unit cell dimensions decrease smoothly in the series from LaHO, CeHO, PrHO to NdHO, in line with the lanthanide contraction. The crystal...

  2. Manipulation of Dy-Mn coupling and ferrielectric phase diagram of DyMn{sub 2}O{sub 5}: The effect of Y substitution of Dy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Z. Y.; Wang, Y. L.; Lin, L.; Liu, M. F.; Li, X.; Yan, Z. B.; Liu, J.-M. [Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-11-07

    DyMn{sub 2}O{sub 5} is an extraordinary example in the family of multiferroic manganites and it accommodates both the 4f and 3d magnetic ions with strong Dy-Mn (4f-3d) coupling. The electric polarization origin is believed to arise not only from the Mn spin interactions but also from the Dy-Mn coupling. Starting from proposed scenario on ferrielectricity in DyMn{sub 2}O{sub 5} where the exchange-strictions associated with the Mn{sup 3+}-Mn{sup 4+}-Mn{sup 3+} blocks and Dy{sup 3+}-Mn{sup 4+}-Dy{sup 3+} blocks generate the two ferroelectric sublattices, we perform a set of characterizations on the structure, magnetism, and electric polarization of Dy{sub 1-x}Y{sub x}Mn{sub 2}O{sub 5} in order to investigate the roles of Dy-Mn coupling in manipulating the ferrielectricity. It is revealed that the non-magnetic Y substitution of Dy suppresses gradually the Dy{sup 3+} spin ordering and the Dy-Mn coupling. Consequently, the ferroelectric sublattice generated by the exchange striction associated with the Dy{sup 3+}-Mn{sup 4+}-Dy{sup 3+} blocks is destabilized, but the ferroelectric sublattice generated by the exchange striction associated with the Mn{sup 3+}-Mn{sup 4+}-Mn{sup 3+} blocks remains less perturbed, enabling the ferrielectricity-ferroelectricity transitions with the Y substitution. A phenomenological ferrielectric domain model is suggested to explain the polarization reversal induced by the Y substitution. The present work presents a possible scenario of the multiferroic mechanism in not only DyMn{sub 2}O{sub 5} but probably also other RMn{sub 2}O{sub 5} members with strong 4f-3d coupling.

  3. Preparatory studies for a high-precision Penning-trap measurement of the {sup 163}Ho electron capture Q-value

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, F. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Johannes Gutenberg-Universitaet, Institut fuer Physik, Mainz (Germany); Beyer, T.; Blaum, K.; Eibach, M.; Eliseev, S.; Nagy, Sz. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Block, M. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz-Institut Mainz, Mainz (Germany); Chenmarev, S.; Novikov, Yu.N. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Saint Petersburg State University, Physical Faculty, Saint Petersburg (Russian Federation); Dorrer, H. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Paul Scherrer Institute, Villigen (Switzerland); Universitaet Bern, Bern (Switzerland); Duellmann, C.E. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz-Institut Mainz, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany); Eberhardt, K. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Helmholtz-Institut Mainz, Mainz (Germany); Grund, J. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany); Koester, U. [Institut Laue-Langevin, Grenoble (France); Renisch, D. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Tuerler, A. [Paul Scherrer Institute, Villigen (Switzerland); Universitaet Bern, Bern (Switzerland); Wendt, K. [Johannes Gutenberg-Universitaet, Institut fuer Physik, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany)

    2015-07-15

    The ECHo Collaboration (Electron Capture {sup 163}Ho) aims to investigate the calorimetric spectrum following the electron capture decay of {sup 163}Ho to determine the mass of the electron neutrino. The size of the neutrino mass is reflected in the endpoint region of the spectrum, i.e., the last few eV below the transition energy. To check for systematic uncertainties, an independent determination of this transition energy, the Q-value, is mandatory. Using the TRIGA-TRAP setup, we demonstrate the feasibility of performing this measurement by Penning-trap mass spectrometry. With the currently available, purified {sup 163}Ho sample and an improved laser ablation mini-RFQ ion source, we were able to perform direct mass measurements of {sup 163}Ho and {sup 163}Dy with a sample size of less than 10{sup 17} atoms. The measurements were carried out by determining the ratio of the cyclotron frequencies of the two isotopes to those of carbon cluster ions using the time-of-flight ion cyclotron resonance method. The obtained mass excess values are ME({sup 163}Ho)= -66379.3(9) keV and ME({sup 163}Dy)= -66381.7(8) keV. In addition, the Q-value was measured for the first time by Penning-trap mass spectrometry to be Q = 2.5(7) keV. (orig.)

  4. Exploring the biocatalytic potential of a DyP-type peroxidase by profiling the substrate acceptance of Thermobifida fusca DyP peroxidase

    NARCIS (Netherlands)

    Loncar, Nikola; Colpa, Dana I.; Fraaije, Marco W.

    2016-01-01

    Dye-decolorizing peroxidases (DyPs) represent a new class of oxidative enzymes for which the natural substrates are largely unknown. To explore the biocatalytic potential of a DyP, we have studied the substrate acceptance profile of a robust DyP peroxidase, a DyP from Thermobifida fusca (TfuDyP). Wh

  5. Gd Transition Probabilities and Abundances

    CERN Document Server

    Den Hartog, E A; Sneden, C; Cowan, J J

    2006-01-01

    Radiative lifetimes, accurate to +/- 5%, have been measured for 49 even-parity and 14 odd-parity levels of Gd II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 611 lines of Gd II. This work is the largest-scale laboratory study to date of Gd II transition probabilities and the first using a high performance Fourier transform spectrometer. This improved data set has been used to determine a new solar photospheric Gd abundance, log epsilon = 1.11 +/- 0.03. Revised Gd abundances have also been derived for the r-process-rich metal-poor giant stars CS 22892-052, BD+17 3248, and HD 115444. The resulting Gd/Eu abundance ratios are in very good agreement with the solar-system r-process ratio. We have employed the increasingly accurate stellar abundance determinations, resulting in large part from the more precise laboratory atomic data, to predict directly the Solar System r-process elemental...

  6. Uniaxial pressure dependencies of the phase transitions in GdMnO3

    Science.gov (United States)

    Baier, J.; Meier, D.; Berggold, K.; Hemberger, J.; Balbashov, A.; Mydosh, J. A.; Lorenz, T.

    2007-03-01

    GdMnO3 shows an incommensurate antiferromagnetic order below ≃42 K, transforms into a canted A-type antiferromagnet below ≃20 K, and for finite magnetic fields along the b-axis ferroelectric order occurs below ≃12 K. From high-resolution thermal expansion measurements along all three principal axes, we determine the uniaxial pressure dependencies of the various transition temperatures and discuss their correlation to changes of the magnetic exchange couplings in RMnO3(R=La,…,Dy).

  7. Activation of Small Molecules by DyI_2 and Dy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results The reactivities of dysprosium diiodide and metallic dysprosium toward small molecules are discussed.For instance,DyI2-induced silyl radical reactions are described.The combination of dysprosium diiodide and dichloromethane can serve as an effective methylene transfer reagent for cyclopropanation of unfunctionalized alkenes beyond that possible with other metal-dichloromethane systems.Furthermore,we report that the combination of chlorosilane and metallic Dy can also serve as an effective prom...

  8. Topics in Ho Morphophonology and Morphosyntax

    Science.gov (United States)

    Pucilowski, Anna

    2013-01-01

    Ho, an under-documented North Munda language of India, is known for its complex verb forms. This dissertation focuses on analysis of several features of those complex verbs, using data from original fieldwork undertaken by the author. By way of background, an analysis of the phonetics, phonology and morphophonology of Ho is first presented. Ho has…

  9. Topics in Ho Morphophonology and Morphosyntax

    Science.gov (United States)

    Pucilowski, Anna

    2013-01-01

    Ho, an under-documented North Munda language of India, is known for its complex verb forms. This dissertation focuses on analysis of several features of those complex verbs, using data from original fieldwork undertaken by the author. By way of background, an analysis of the phonetics, phonology and morphophonology of Ho is first presented. Ho has…

  10. DySectAPI: Scalable Prescriptive Debugging

    DEFF Research Database (Denmark)

    Jensen, Nicklas Bo; Karlsson, Sven; Quarfot Nielsen, Niklas;

    We present the DySectAPI, a tool that allow users to construct probe trees for automatic, event-driven debugging at scale. The traditional, interactive debugging model, whereby users manually step through and inspect their application, does not scale well even for current supercomputers. While...

  11. Afterglow Emission of Er3+, Ho3+ and Tm3+ in Gadolinium Oxysulfide%Er3+,Ho3+和Tm3+硫氧化钆中的余辉发光

    Institute of Scientific and Technical Information of China (English)

    刘应亮; 宋春燕; 张静娴; 袁定胜; 黄浪欢; 容建华; 张俊文

    2005-01-01

    The new Er3+, Ho3+ and Tm3+ doped gadolinium oxysulfide phosphors with the long afterglow emission were synthesized by solid-state reaction method. The synthesized phosphors were characterized by X-ray diffraction. The excitation and photolumineseenee spectra, afterglow spectra and afterglow decay curve were examined by fluorescence spectroscopy. The afterglow spectra of Gd2O2S:Er3+, Mg, Ti showed typical transitions of Er3+ at 528(2H11/2→4I15/2), 548 (4S3/2 →4I15/2) and 669 nm (4F9/2→4I15/2). In the afterglow spectra of Gd2O2S: Ho3+, Mg, Ti,typical transitions of Ho3+ at 546 nm (5S2→5I8), 651 and 661 nm (2F5→5I8) were observed. In Gd2O2S:Tm3+, Mg,Ti, the afterglow emission at 800 nm (1G4→3H5) of Tm3+ was seen. The meehnism and model of afterglow energy transfer were proposed.

  12. Steric hindrances create a discrete linear Dy4 complex exhibiting SMM behaviour.

    Science.gov (United States)

    Lin, Shuang-Yan; Zhao, Lang; Ke, Hongshan; Guo, Yun-Nan; Tang, Jinkui; Guo, Yang; Dou, Jianmin

    2012-03-21

    Two linear tetranuclear lanthanide complexes of general formula [Ln(4)(L)(2)(C(6)H(5)COO)(12)(MeOH)(4)], where HL = 2,6-bis((furan-2-ylmethylimino)methyl)-4-methylphenol, () and Ln(III) = Dy(III) (1) and Gd(III) (2), have been synthesized and characterized. The crystal structural analysis demonstrates that two Schiff-base ligands inhibit the growth of benzoate bridged 1D chains, leading to the isolation of discrete tetranuclear complexes due to their steric hindrances. Every Ln(III) ion is coordinated by eight donor atoms in a distorted bicapped trigonal-prismatic arrangement. Alternating current (ac) susceptibility measurements of complex 1 reveal a frequency- and temperature-dependent out-of-phase signal under zero dc field, typical of single-molecule magnet (SMM) behaviour with an anisotropic barrier Δ(eff) = 17.2 K.

  13. Octupole correlations in N =88 154Dy : Octupole vibration versus stable deformation

    Science.gov (United States)

    Zimba, G. L.; Sharpey-Schafer, J. F.; Jones, P.; Bvumbi, S. P.; Masiteng, L. P.; Majola, S. N. T.; Dinoko, T. S.; Lawrie, E. A.; Lawrie, J. J.; Negi, D.; Papka, P.; Roux, D.; Shirinda, O.; Easton, J. E.; Khumalo, N. A.

    2016-11-01

    We report on low-spin states of 154Dy populated via the reaction 155Gd (3He,4 n ) with a beam energy of 37.5 MeV from the Separated Sector Cyclotron at iThemba Laboratory. The AFRODITE γ-ray spectrometer was used to establish new E 1 transitions between bands of opposite parity. The measurements broaden the N =88 systematics on the relationship between the first excited positive-parity pairing isomer band and the lowest-lying negative-parity band as the nuclear quadrupole deformation decreases with increasing proton number. In a region of strong octupole correlations the data suggest that the spectroscopy of N =88 nuclei is driven by stable octupole deformations and not by vibrations.

  14. Crystal structure of Tb5Ni2In4 and Y5Ni2In4, and magnetic properties of Dy5Ni2In4

    Energy Technology Data Exchange (ETDEWEB)

    Provino, A.; Mudryk, Y.; Smetana, V.; Manfrinetti, P.; Pecharsky, V.K.; Gschneidner Jr, Karl; Corbett, J.D.

    2012-02-27

    The crystal structure of the R5Ni2In4 intermetallic compounds was earlier reported for R Ho, Er, Tm, and Lu (Lu5Ni2In4-type, oP22, Pbam); more recently the isostructural phases Dy5Ni2In4 and Sc5Ni2In4 have also been identified. Three inequivalent crystallographic sites are occupied by the R atoms in these compounds. We have synthesized and characterized Dy5Ni2In4 and the two new isotypic compounds Tb5Ni2In4 and Y5Ni2In4. So far, none of the physical properties have been reported on any of these phases; in this article we report on the physical properties of the Dy5Ni2In4 and the crystal structure of Tb5Ni2In4 and Y5Ni2In4 compounds. Measurements of the magnetic properties performed on Dy5Ni2In4 show a ferromagnetic-like ordering with a T-C approximate to 105 K, followed by multiple magnetic orderings at lower temperatures. The fit of the inverse susceptibility in the paramagnetic state follows the Curie-Weiss law, where mu(eff). - 10.3 mu(B)/Dy-atom (close to theoretical value of 10.64 mu(B) for the free ion Dy3+) and a positive paramagnetic Curie temperature theta(p) - 58 K. Ni atoms are most likely to be nonmagnetic. The heat capacity also shows three peaks: a large one at 103K and two weaker at 12 and 8 K, respectively; the in-field heat capacity data corroborate these results, suggesting ferromagnetic and antiferromagnetic orderings at the temperature of 103 and 12 K, respectively. Low temperature x-ray diffraction has shown that the compound does not undergo any structural change down to 5K. (C) 2012 American Institute of Physics

  15. Thermophysical properties of Gd{sub 2}Zr{sub 2}O{sub 7} powders prepared by mechanical milling: Effect of homovalent Gd{sup 3+} substitution

    Energy Technology Data Exchange (ETDEWEB)

    Díaz-Guillén, J.A., E-mail: jadiaz@itsaltillo.edu.mx [División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Saltillo, 25280 Saltillo, Coahuila (Mexico); Durá, O.J. [GFMA, Departamento de Física Aplicada, Escuela Técnica Superior de Ingenieros Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Díaz-Guillén, M.R. [Instituto de Investigaciones Eléctricas, 62490 Cuernavaca, Morelos (Mexico); Bauer, E. [Institute of Solid State Physics, Vienna University of Technology, Wien A-1040 (Austria); López de la Torre, M.A. [GFMA, Departamento de Física Aplicada, Escuela Técnica Superior de Ingenieros Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Fuentes, A.F. [Cinvestav Unidad Saltillo, Apartado Postal 663, 25000 Saltillo, Coahuila (Mexico)

    2015-11-15

    This contribution analyzes the thermophysical properties of Gd{sub 1.6}Ln{sub 0.4}Zr{sub 2}O{sub 7} (Ln = La{sup 3+}, Nd{sup 3+}, Sm{sup 3+}, Dy{sup 3+} and Er{sup 3+}) ceramics synthesized at room temperature, by mechanically milling stoichiometric mixtures of high purity oxides. Regardless of chemical composition, powders milled for 27 h show XRD patterns similar to fluorite-type materials. Post-milling thermal treatments at 1500 °C, facilitates the evolution to the ordered pyrochlore derivative for Gd{sub 2}Zr{sub 2}O{sub 7}, and the La{sup 3+}-, Nd{sup 3+}-, and Sm{sup 3+}-containing materials. By contrast, samples containing the smaller lanthanides (Dy{sup 3+} or Er{sup 3+}), maintain the fluorite structure. Thermal conductivity of the as-prepared samples was obtained as a function of temperature, from thermal diffusivity, heat capacity and density values, using sintered pellets. We found that doping has an important effect in lowering Gd{sub 2}Zr{sub 2}O{sub 7} thermal conductivity, with final values ranging from 1.22 to 1.94 W m{sup −1} K{sup −1}; Nd{sup 3+}- and Er{sup 3+}-containing samples represent an optimum combination of defects and disordering of oxygen vacancies that generate the lowest conductivity values of all samples tested. - Highlights: • Gd{sub 2}Zr{sub 2}O{sub 7} doped with different lanthanides was synthesized by mechanical milling. • Smaller Ln{sup 3+} yield fluorites whereas larger lanthanides produce pyrochlores. • Thermophysical properties of the samples were measured as a function of temperature. • All samples show low thermal conductivities, and might find application as TBCs. • Doping is a valid strategy to increase Gd{sub 2}Zr{sub 2}O{sub 7} thermal resistance.

  16. Magnetic, Caloric and Crystallographic Properties of Dy5(SixGe1-x)4 Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivchenko, Vitaliy Vladislavovich [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Polycrystals of the intermetallic compound of the Dy5(SixGe1-x)4 system, where x = 0, 0.25, 0.5, 0.625, 0.675, 0.725, 0.75, 0.775, 0.825, 0.875, and 1, have been prepared by electric-arc-melting on water-cooled copper hearth in an argon atmosphere. A study of phase relationships and crystallography in the pseudobinary system Dy5(SixGe1-x)4 using X-ray powder diffraction data and optical metallography was completed. It revealed that silicides in the composition range from 0.825 to 1 crystallize in the Gd5Si4-type crystal structure: germanides in the composition range from 0 to 0.625 crystallize in the Sm5Ge4-type structure, and alloys with intermediate composition range from 0.675 to 0.775 crystallize in the monoclinic Gd5Si2Ge2-type structure. The -ΔSm values were determined from magnetization measurements for 7 alloys. The alloys with a monoclinic crystal structure which belong to an intermediate phase region have large MCE value, which exceeds those observed in the other two phase regions by 300 to 500%. The nature of the observed magnetic and structural transformations in the Dy5(SixGe1-x)4 system seems to be similar with those reported for the Gd5(SixGe1-x)4 system. However, the interval and concentration range of three different phase regions in the Dy5(SixGe1-x)4 system are different from that observed in Gd-based alloys. A non-collinear ordering of magnetic moments at low temperature was observed for the alloys with monoclinic crystal structure. The Dy5Si3Ge alloy exhibited FM phase transition below Curie temperature. A series of magnetic transitions were observed at low temperature in the Dy5(SixGe1-x

  17. Electroreduction of Ho3+ on Nickel Cathode in Molten KCl-HoCl3

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The cyclic voltammetry, open current potential-time curve after potentiostatic electrolysis, the current-time curve at potential step, XRD, EDAX and EPMA were used to study the electrode process of Ho3+ reduction on nickel electrode in molten KCl-HoCl3 and the phases of surface alloy layer. The Ho-Ni alloys were deposited when Ho3+ was reduced on the nickel electrode. The free energies of formation for the intermetallic compounds between Ho and Ni, the diffusion coefficients and diffusion activation energy of Ho atom in the alloy phase were determined.

  18. Magnetic, Caloric and Crystallographic Properties of Dy5(SixGe1-x)4 Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivchenko, Vitaliy Vladislavovich [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    A study of a series of Dy5(SixGe1-x)4 alloys using dc and ac magnetic susceptibility, magnetization, heat capacity, and x-ray powder diffraction techniques revealed that the variation of the magnetic properties and crystal structures with composition is similar to that observed in the Gd5(SixGe1-x)4 system, except that the magnetic ordering temperatures are lower. The magnetic phase transition temperatures vary from ~ 46K (Dy5Ge4) to ~ 137K (Dy5Si4). The intermediate ternary phase Dy5Si3Ge undergoes a first order magnetic phase transition at ~ 65K. The value of magnetic entropy change for this composition is quite large (-34J/kgK for magnetic field change from 0 to 50kOe), compared to the values for the two end members (-7 J/kgK for Dy5Ge4 and -12.5J/kgK for Dy5Si4). The magnetization and ac susceptibility measurements showed that alloys with monoclinic crystal structure have a non-collinear ordering of the magnetic moments at low temperatures. The alloy Dy5Si3Ge appears to exhibit a FM phase transition below the Curie temperature at 65K. Also a series of critical fields are observed at low temperature during magnetization vs magnetic field measurements in all of the Dy5(SixGe1-x)4 alloys regardless type of crystal structure. The Dy5(SixGe1-x)4 alloys, where 0.67≤x≤1, may be useful magnetic refrigerant materials in the ~50 to ~160K temperature range.

  19. Gd-Tex Pharmacyclics Inc.

    Science.gov (United States)

    Radford, I R

    2000-12-01

    Pharmacyclics is developing Gd-Tex (gadolinium texaphyrin) as a radiosensitizer for the potential treatment of various cancers including brain metastases and primary brain tumors, pancreatic tumors, lung tumors and pediatric cancers [196711], [348919]. The compound entered phase III pivotal trials for brain metastases in September 1998 [323929]. Phase I clinical trials for the treatment of primary brain tumors and pancreatic cancer have been initiated while several trials in other cancer types are in the planning stages [367716]. In September 1998, Pharmacyclics announced the initiation of a pivotal phase III trial for the treatment of patients with brain metastases. This multicenter trial originally included 30 sites in the US, Canada and Europe, and was expected to enroll 425 patients. The FDA agreed that this trial qualified for Fast Track review if efficacy end-points are met [301265]. By October 2000, nearly all 450 patients in 50 sites had been completed [375959], [387023]. In September 2000, Pharmacyclics and the National Cancer Institute (NCI) initiated two phase I trials of Gd-Tex. The first was to determine the safety of two different dosing regimens of the drug during preoperative radiotherapy after induction chemotherapy in patients with stage IIA non-small cell lung cancer (NSCLC). The second would examine the use of Gd-Tex in combination with stereotactic Gamma Knife radiosurgery in patients with primary brain tumors known as glioblastoma multiforme [381561]. A phase Ib/II trial, for brain metastases, was conducted in America and France, and involved over 100 patients. At the ASCO 1998 meeting, interim tumor response data were presented for 37 patients. The overall tumor response rate (complete plus partial response rate) was 73%. Furthermore, MRI scanning confirmed that Gd-Tex accumulated selectively in tumors [287459]. Full results were announced in October 1998 at the American Society of Therapeutic Radiology and Oncology. Following ten daily

  20. Thermochromism and fluorescence in dyed PEO films

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, Archana; S, Raghu; V, Mini; C, Sharanappa; H, Devendrappa, E-mail: dehu2010@gmail.com [Dept. of Physics, Mangalore University, Managalagangothri, Mangalore--574199 (India)

    2015-06-24

    The optical absorbance spectra of solution casted pure & methyl blue (MB) dyed polyethylene oxide (PEO) films were recorded in a wavelength range from 190-1100nm at different temperatures. The absorbance was found to increases with increasing temperature. Fluorescence micrographs confirmed the interaction between polymer and dye and also revealed decreased crystallinity of the sample. Fluorescence quantum yield has been calculated with the help of fluorescence spectra.

  1. Sub-6 nm monodisperse hexagonal core/shell NaGdF4 nanocrystals with enhanced upconversion photoluminescence.

    Science.gov (United States)

    Liu, Jing; Chen, Guanying; Hao, Shuwei; Yang, Chunhui

    2017-01-07

    The ability to fabricate lanthanide-doped upconversion nanocrystals (UCNCs) with tailored size and emission profile has fuelled their uses in a broad spectrum of biological applications. Yet, limited success has been met in the preparation of sub-6 nm UCNCs with efficient upconversion photoluminescence (UCPL), which enable high contrast optical bioimaging with minimized adverse biological effects entailed by size-induced rapid clearance from the body. Here, we present a simple and reproducible approach to synthesize a set of monodispersed hexagonal-phase core NaGdF4:Yb/Ln (Ln = Er, Ho, Tm) of ∼3-4 nm and core/shell NaGdF4:Yb/Ln@NaGdF4 (Ln = Er, Ho, Tm) UCNCs of ∼5-6 nm. We show that the core/shell UCNCs can be up to ∼1000 times more efficient than the corresponding core UCNCs due to the effective suppression of surface-related quenching effects for the core. The observation of prolonged PL lifetime for the core/shell than that for the core UCNCs demonstrates the role of the inert shell layer for the protection of the core. The achievement of sub-6 nm NaGdF4 UCNCs with significantly improved luminescence efficiency constitutes a solid step towards high contrast UCPL optical imaging with secured biological safety.

  2. Shape coexistence in 153Ho

    CERN Document Server

    Pramanik, Dibyadyuti; Sarkar, M Saha; Bisoi, Abhijit; Ray, Sudatta; Dasgupta, Shinjinee; Chakraborty, A; Krishichayan,; Kshetri, Ritesh; Ray, Indrani; Ganguly, S; Pradhan, M K; Basu, M Ray; Raut, R; Ganguly, G; Ghugre, S S; Sinha, A K; Basu, S K; Bhattacharya, S; Mukherjee, A; Banerjee, P; Goswami, A

    2016-01-01

    The high-spin states in 153Ho, have been studied by 139 57 La(20Ne, 6n) reaction at a projectile energy of 139 MeV at Variable Energy Cyclotron Centre (VECC), Kolkata, India, utilizing an earlier campaign of Indian National Gamma Array (INGA) setup. Data from gamma-gamma coincidence, directional correlation and polarization measurements have been analyzed to assign and confirm the spins and parities of the levels. We have suggested a few additions and revisions of the reported level scheme of 153Ho. The RF-gamma time difference spectra have been useful to confirm the half-life of an isomer in this nucleus. From the comparison of experimental and theoretical results, it is found that there are definite indications of shape coexistence in this nucleus. The experimental and calculated lifetimes of several isomers have been compared to follow the coexistence and evolution of shape with increasing spin.

  3. The melting diagram of the Ti-Dy-Si system in the Ti-Ti{sub 5}Si{sub 3}-Dy{sub 5}Si{sub 3}-Dy region

    Energy Technology Data Exchange (ETDEWEB)

    Fartushna, Yu. [Frantsevich Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhizhanovsky Street, 03142 Kiev (Ukraine)], E-mail: julia@ipms.kiev.ua; Meleshevich, K.; Samelyuk, A.; Bulanova, M. [Frantsevich Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhizhanovsky Street, 03142 Kiev (Ukraine)

    2009-04-03

    The phase equilibria in the Ti-Ti{sub 5}Si{sub 3}-Dy{sub 5}Si{sub 3}-Dy part of the Ti-Dy-Si system were studied by DTA, X-ray diffraction, metallography and EPMA. The melting diagram, isopleths at 5Si, 65Ti and 65Dy, and a reaction scheme were constructed. The solidus surface is characterized by the following three-phase fields: <{beta}-Ti> + + DySi>, <{beta}-Ti> + DySi> + <{alpha}-Dy>, DySi> + <{alpha}-Dy> + <Dy{sub 5}Si{sub 3}>, and + DySi> + <Dy{sub 5}Si{sub 3}>. The first two fields form via U-type equilibria, L + {r_reversible} <{beta}-Ti> + DySi> and L + <{beta}-Ti> {r_reversible} DySi> + <{alpha}-Dy>, at 1320 and 1170 deg. C, respectively. The third three-phase field results from an invariant eutectic four-phase equilibrium, L {r_reversible} DySi> + <{alpha}-Dy> + <Dy{sub 5}Si{sub 3}>, at 1157 {+-} 6 deg. C. The fourth one is the result of a P-type equilibrium, L + + <Dy{sub 5}Si{sub 3}> {r_reversible} DySi>. The temperature of the latter was estimated to be within the interval 1650-1700 deg. C.

  4. Improvement of Thermal Stability of Nd-Tb-Fe-Co-B Sintered Magnets by Additions of Pr, Ho, Al, and Cu

    Directory of Open Access Journals (Sweden)

    A. A. Lukin

    2012-01-01

    Full Text Available The present work investigates the influence of Pr, Al, Cu, B and Ho which were introduced into the Co-containing sintered magnets of Nd-Dy-Tb-Fe-Co-B type on the magnetic parameters (α, Hci, Br, BHmax⁡. The effect of heat treatment parameters on magnetic properties was also studied. It was revealed that the essential alloying of NdFeB magnets by such elements as Dy, Tb, Ho, Co as well as by boron-forming elements, for example, by titanium, may lead to reducing of F-phase quantity, and, as a consequence, to decreasing of magnetic parameters. It was also shown that additional doping of such alloys by Pr, B, Al and Cu leads to a significant increase of the quantity of F-phase in magnets as well as solubility of the Dy, Tb, Ho and Co in it. This promotes the increase of magnetic parameters. It was possible to attain the following properties for the magnets (Nd0,15Pr0,35Tb0,25Ho0,2515(Fe0,71Co0,29bal ⋅ Al0,9Cu0,1B8,5 (at. % after optimal thermal treatment {1175 K (3,6–7,2 ks with slow (12–16 ks cooling to 675 K and subsequently remaining at T=775 K for 3,6 ks—hardening}: Br=0,88 T, Hci=1760 kA/m, BHmax⁡=144 kJ/m3, α<|0,01|%/K in the temperature interval 223–323 K.

  5. Magnetic properties and XPS of Dy-Y and Dy-Nd alloys

    Institute of Scientific and Technical Information of China (English)

    戴闻; 沈保根; 李德新; 何文望; 叶小燕

    1996-01-01

    The magnetic properties and X-ray photoelectron spectroscopy (XPS) spectra in the Dy100-xYx and Dy100-zNdz rare-earth alloys are studied.The magnetism measurements show that the dhcp crystal-field influence in the Dy-Nd alloys,which tends to destroy the orbital moment,does not vanish even though a field of 6T is applied.With increasing Y (or Nd) content the temperature region corresponding to helical phase becomes wider (or narrower).The XPS records suggest that the property of the valence fluctuation in neodymium tends to increase the Fermi wave vector kF of the Dy-Nd alloys.This testifies that the abrupt dropping of the Neel temperature,as Nd is introduced,is not only due to a dilution effect of Nd.The introduction of light rare earths into heavy ones is favorable for suppressing the helical phase in the alloys and overcoming the negative magnetocaloric effect.This result will play a guiding role in designing composite magnetic refrigeration working substances.

  6. Prospect of TbDyFe Magnetostrictive Material

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1. Global Market: Increasing Demand for TbDyFe Mater There is steady demand for TbDyFe materials international market, especially in USA, Europe and Jap Following table shows global status of such materials si their emergence in 1984. Development course of American Etrema Company reflects the prospect of such materials. At present, besi domestic market, Etrema Company has sales subsidiarie

  7. Základní charakteristiky vína kvašeného ze samotoku a z lisovaného moštu

    OpenAIRE

    Becková, Eliška

    2010-01-01

    Tato práce se zabývá výrobou a školením bílého a červeného vína. První část je věnována teoretickými procesy a postupy při výrobě vína, popisuje sklizeň hroznů, kvašení, školení vína, chemické složení hroznů i vína, choroby a vady vína. Druhá část krátce popisuje vybrané odrůdy podrobené praktické úloze. Třetí část se zabývá praktickou výrobou vína a následně chemickými zkouškami. Odebírané mošty ze samotoku, středu lisování a dolisků byly ponechány volnému kvašení a poté byly podrobeny chemi...

  8. Ferromagnetic properties of fcc Gd thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bertelli, T. P., E-mail: tambauh@gmail.com; Passamani, E. C.; Larica, C.; Nascimento, V. P.; Takeuchi, A. Y. [Universidade Federal do Espírito Santo, Departamento de Física, Vitória/ES 29075-910 (Brazil); Pessoa, M. S. [Universidade Federal do Espírito Santo, Departamento de Ciências Naturais, São Mateus/ES 29932-540 (Brazil)

    2015-05-28

    Magnetic properties of sputtered Gd thin films grown on Si (100) substrates kept at two different temperatures were investigated using X-ray diffraction, ac magnetic susceptibility, and dc magnetization measurements. The obtained Gd thin films have a mixture of hcp and fcc structures, but with their fractions depending on the substrate temperature T{sub S} and film thickness x. Gd fcc samples were obtained when T{sub S} = 763 K and x = 10 nm, while the hcp structure was stabilized for lower T{sub S} (300 K) and thicker film (20 nm). The fcc structure is formed on the Ta buffer layer, while the hcp phase grows on the fcc Gd layer as a consequence of the lattice relaxation process. Spin reorientation phenomenon, commonly found in bulk Gd species, was also observed in the hcp Gd thin film. This phenomenon is assumed to cause the magnetization anomalous increase observed below 50 K in stressed Gd films. Magnetic properties of fcc Gd thin films are: Curie temperature above 300 K, saturation magnetization value of about 175 emu/cm{sup 3}, and coercive field of about 100 Oe at 300 K; features that allow us to classify Gd thin films, with fcc structure, as a soft ferromagnetic material.

  9. COLOR STABILITY OF NATURALLY DYED DENIM FABRICS

    Directory of Open Access Journals (Sweden)

    SUBTIRICA Adriana-Ioana

    2014-05-01

    Full Text Available The desire to colour textiles is as old as spinning and weaving. Natural dyes have been used since thousands of years for their long endurance, soft and elegant colours. But the invention of synthetic dyes has limited the application of natural dyes. The health hazards associated with the use of synthetic dyes and also the increased environmental awareness have revived the use of natural dyes during the recent years. The major performance characteristic of a dye is its ability to maintain the colour in normal use and is known as colorfastness. The study provides information regarding colour fastness properties of naturally dyed denim fabrics. Three vegetable materials were used for dyeing denim fabrics: Punica granatum (bark powder, Indigofera tinctoria (leave powder and Juglans regia (walnut dried shells. The results of the study indicated that using Walnut shells and Punica granatum deeper and more stable shades of colors are obtained in comparison with Indigofera Tinctoria dyed denim samples. All samples highlight a change in color in the sense of fading which has occurred to the highest extent when exposed to artificial light and washing. When tested against water, alkaline and acid perspiration, it is noticed that better results are obtained, and color change appear in a smaller extent.

  10. Theoretical Studies of the HO/HO2 Catalytic Cycle for Ozone Destruction

    Science.gov (United States)

    Walch, Stephen P.; Langhoff, Steve R. (Technical Monitor)

    1996-01-01

    Recently it has been determined that the HO/HO2 catalytic cycle accounts for nearly one-half of the total ozone depletion in the lower stratosphere. The catalytic cycle is: (1) HO + O3 yields HO2 + O2; (2) HO2 + O3 yields HO + O2 + O2. The net reaction is 2O3 yields 3O2. The rate limiting step in this process is the reaction of HO2 with ozone. There is a problem extending the experimental measurement of the rate of this reaction over the range 233-400 K down to stratospheric temperatures of 210-220 K. Therefore we have undertaken a project to determine the temperature dependence of the rate constant for this reaction in the low temperature region. The first step in this project, which is described in this poster, is the determination of the relevant potential energy surfaces. The calculations use CASSCF/derivative methods to define the pathways followed by CASSCF/ACPF to determine the energetics. The HO + O3 reaction is found to proceed through an HO4 complex, which is unstable with respect to HO2 + O2. The HO2 +O3 reaction is more complex. One pathway, which has been characterized, is the formation of an HO5 complex which decomposes to HO3 + O2 and subsequently to HO + O2 + O2. Another pathway, which is believed to also play a role, is hydrogen abstraction to give O2 + HO3 and subsequent decomposition of HO3 to HO + O2. Isotopic labeling experiments indicate that the later pathway is dominant. However, so far attempts to locate the saddle point for this pathway have not been successful. We have also characterized the potential energy surfaces for a number of species involved in these reactions, including HO3 and triplet O4. The triplet O4 species is probably involved in the reaction of vibrationally excited O2 with ground state O2 leading to O3 + O. The latter reaction is believed to be important as an additional source of stratospheric ozone.

  11. [Spectroscopy parameters of Ho3+ in Ho3+ : FOG and Ho3+ : FOV].

    Science.gov (United States)

    Yang, Xiao-Dong; Chen, Ying; Chen, Xiao-Bo; Sawarobori, N; Wang, Shui-Feng; Zhou, Yong-Fen; Li, Song; Xu, Yi-Zhuang; Cheng, Huan-Li; Yang, Guo-Jian

    2013-07-01

    In the present paper, the absorption spectra of Ho3+ (0.5 mol%)-doped oxyfluoride glass (FOG) sample and Ho3+ (0.5 mol%)-doped oxyfluoride vitroceramics (FOV) sample were measured through experiment. The authors calculated the intensity parameters omega 2, 4, 6 of the two materials according to J-O theory, and analyzed the possible reason for the difference between the two materials on the intensity parameters. After that the authors calculated oscillator strength, spontaneous radiative transition rate, branching ratio and integrated emission cross section and some other spectroscopic parameters of several excited states and then made a comparative analysis of the two materials based on these spectroscopic parameters. The authors found that the oscillator strength of trivalent holmium iron in FOV is about the same with the oscillator strength in YAlO3 and is similar to oscillator strength in FOG, while slightly larger than in that LBTAF and much larger than that in LaF3 and ZBLAN. By analyzing the calculated spectroscopic parameters, it can be found that some transitions, especially 5I7 --> 5I8, 5F5 --> 5I8 etc., have a relatively large oscillator strengths(larger than 10(-6)) and large integrated emission cross sections(larger than 10(-18) cm). These transitions have the conditions to form laser passages, so they are worth a lot of attention. At last, application prospects of several strong luminescence transitions were concluded.

  12. Gadolinium (Gd) Oxide, Carbide, and Carbonyl Cation Bond Energies and Evaluation of the Gd + O → GdO(+) + e(-) Chemi-Ionization Reaction Enthalpy.

    Science.gov (United States)

    Demireva, Maria; Kim, JungSoo; Armentrout, P B

    2016-11-03

    Guided ion beam mass spectrometry (GIBMS) is used to measure the kinetic energy dependent product ion cross sections for reactions of the lanthanide metal gadolinium cation (Gd(+)) with O2, CO2, and CO and for reactions of GdO(+) with CO, O2, and Xe. GdO(+) is formed through barrierless and exothermic processes in the reactions of Gd(+) with O2 and CO2. All other reactions observed are endothermic, and analyses of their kinetic energy dependent cross sections yield 0 K bond dissociation energies (BDEs) for GdO(+), GdC(+), and GdCO(+). The 0 K BDE for GdO(+) is determined from five different reactions to be 7.69 ± 0.10 eV, and this value is combined with literature data to derive the ionization energy (IE) of GdO as 5.82 ± 0.16 eV. Additionally, GdC(+) and GdCO(+) BDEs of 3.18 ± 0.18 eV and 0.65 ± 0.06 eV are obtained from analysis of the Gd(+) reactions with CO and CO2, respectively. Theoretical GdO(+), GdC(+), and GdCO(+) BDEs are calculated for comparison with experiment using various Gd basis sets with an effective core potential and several levels of theory. For calculations that correctly predict a (10)D ground state for Gd(+), good agreement between theoretical and measured GdC(+) and GdCO(+) BDEs is obtained, whereas the GdO(+) BDE is underestimated in these calculations by about 0.8 eV. Additional BDEs for GdO(+) and GdC(+) are calculated using triple- and quadruple-ζ correlation consistent all-electron basis sets for Gd. Calculations with these basis sets provide better agreement with experiment for GdO(+) but not for GdC(+). The measured Gd(+) oxide, carbide, and carbonyl BDEs are similar to those for the group 3 metal ions, Sc(+) and Y(+). This is attributed to similarities in the ground state electronic configurations of these metal ions leading to similar interaction strengths. The experimental GdO(+) BDE measured here combined with the known IE of Gd is used to determine an exothermicity of 1.54 ± 0.10 eV for the Gd chemi-ionization reaction

  13. Formation of ternary Mg–Cu–Dy bulk metallic glasses

    Indian Academy of Sciences (India)

    X F Wu; Y Kang; F F Wu; K Q Qiu; L K Meng

    2011-12-01

    The glass-forming ability (GFA) of ternary Mg–Cu–Dy alloys was systematically investigated by using differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) techniques. The results showed that a series of ternary Mg–Cu–Dy bulk metallic glasses (BGMs) with a diameter of 4–8 mm were successfully fabricated in the system with conventional Cu-mold casting method. Mg55Cu32Dy13, Mg60Cu27Dy13, Mg65Cu25Dy10 and Mg70Cu17Dy13 BMGs exhibit a clear glass transition, a broad supercooled liquid region and different crystallization and melting behaviours. They have supercooled liquid region ($\\Delta T_{x}$) from 41 K to 65 K, reduced glass transition temperature ($T_{rg}$) from 0.5363 to 0.5974 and parameter from 0.4038 to 0.4136. The shows a relatively good agreement with the GFA of the BGMs. On the other hand, a high fracture compressive strength of 624 MPa was obtained for Mg60Cu27Dy13 BMG.

  14. Search for superdeformed bands in {sup 154}Dy

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Khoo, T.L. [and others

    1995-08-01

    The island of superdeformation in the vicinity of the doubly magic {sup 152}Dy yrast superdeformed (SD) band is thought to be well understood in the framework of cranked mean field calculations. In particular, the calculations suggested that in {sup 154}Dy there should be no yrast or near yrast SD minimum in the 40-60 h spin range, where SD bands in this mass region are thought to be {sup 153}Dy nucleus, it is populated. However, with the presence of five SD bands in the neighboring necessary to ascertain if the addition of one single neutron diminishes the importance of shell effects to the extent that superdeformation can no longer be sustained. In an experiment utilizing the increased resolving power of the early implementation phase of Gammasphere, the reaction {sup 122}Sn({sup 36}S,4n) at 165 MeV was employed to populate high spin states in {sup 154}Dy. In a four-day run with 36 detectors, over one billion triple and higher fold coincidence events were recorded. One new SD band was identified and was assigned to {sup 154}Dy. From comparisons with the Im{sup (2)} moments of inertia of the SD bands in {sup 152}Dy and {sup 153}Dy, a configuration based on (514)9/2{sup 2} neutrons coupled to the {sup 152}Dy SD core was proposed. One unexpected and as yet unexplained feature of this new SD band is that the transition energies are almost identical to those of an excited SD band in {sup 153}Dy. It is also worth noting that the feeding of the yrast states is similar to that achieved by the deexcitation from the ensemble of all entry states in the reaction. This observation emphasizes the statistical nature of the decay-out process. A paper reporting these results was accepted for publication.

  15. Clinical trial of {sup 166}Ho-CHICO in the treatment of rheumatoid knee synovitis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. Y.; Yoo, D. H.; Bae, S. C.; Lee, I. H.; Jung, S. S.; Jun, J. B.; Kim, T. H.; Kim, S. S. [Hanyang Univ., Seoul (Korea)

    2000-03-01

    The untreated, chronic synovial inflammation leads to pannus formation and eventual destruction of the articular cartilage. In cases where medical therapy was unsuccessful, surgical of radiation synovectomy over surgical synovectomy are (1) greater destruction of diseased synovium, (2) reduced Potential for blood clots and infection, (3) no requirement for anesthesia, and (4) less costly and less time consuming. Recently KAERI developed Dy-165 HMA, which was characterized by the absence of iron and a higher concentration of dysprosium. And then more recently KAERI also developed {sup 16H}o-CHICO, which was characterized by relatively longer half-life (26.8 hr), more biological due to organic nature of chitosan, more even spatial distribution due to colloidal solution, and more absorbable to synovium than Dy-165 HMA. These long-term follow-up results indicate that the {sup 166}Ho-CHICO is an effective and safe agent for radiation synovectomy for knee synovitis in patients with rheumatoid arthritis as well as the other chronic arthritides. But further large scaled and controlled study are required. 16 refs. (Author)

  16. Excited quasiparticles and entropy in 161,162Dy

    Science.gov (United States)

    Razavi, R.; Mohassel, A. Rashed; Mohammadi, S.

    2015-11-01

    In this paper, the nuclear level densities of 161,162Dy is studied by the use of a microscopic theory which includes nuclear pairing interaction. It is based on the modified harmonic oscillator model according to the Nilsson potential. The entropy of even-odd and even-even nuclei as a function of nuclear temperature is obtained. The entropy excess of 161Dy is compared with that of 162Dy. It is concluded that the difference is related to the entropy carried by the neutron hole coupled to the even-even core. The numbers of excited quasiparticles are calculated. Good agreement was observed between calculated results and the experimental data.

  17. Luminescence behavior of Dy 3+ ions in lead borate glasses

    Science.gov (United States)

    Pisarska, Joanna

    2009-10-01

    Dy-doped lead borate glasses were studied. The luminescence spectra showed two characteristic bands at 480 and 573 nm due to 4F 9/2- 6H 15/2 (blue) and 4F 9/2- 6H 13/2 (yellow) transitions of Dy 3+. The yellow/blue luminescence of trivalent dysprosium was analyzed as a function of the B 2O 3/PbO ratios, the activator (Dy 3+) and the PbX 2 (X = F, Cl, Br) content.

  18. Probing Dy{sup 3+} magnetic moments in multiferroic perovskite DyMnO{sub 3} by optical spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kashchenko, M.A. [Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Dolgoprudnyi (Russian Federation); Klimin, S.A.; Popova, M.N. [Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow (Russian Federation); Balbashov, A.M. [Moscow Power Engineering Institute (Technical University), Moscow (Russian Federation)

    2016-06-15

    We present a detailed temperature-dependent (4-300 K) spectroscopic study of DyMnO{sub 3} single crystals with distorted perovskite structure. Energies of 36 crystal-field levels of Dy{sup 3+} in paramagnetic DyMnO{sub 3} were determined. The Dy{sup 3+} ground Kramers doublet does not split at T{sub N}{sup Mn} = 39 K and splits below T{sub lock} = 18 K. The splitting grows fast at temperatures near T{sub N}{sup Dy} = 6.5 K and reaches Δ{sub 0} ∼ 11 ± 2 cm{sup -1} at 4 K. Using the experimental temperature dependence Δ{sub 0}(T), we calculate the dysprosium magnetic moment m{sub Dy}(T) and the dysprosium contribution into specific heat and magnetic susceptibility. Analysing all the experimental data, we conclude that the Dy-Mn interaction is of the Dzyaloshinskii-Moriya type. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. A trimetallic strategy towards ZnDyCr and ZnDyCo single-ion magnets.

    Science.gov (United States)

    Hu, Kong-Qiu; Jiang, Xiang; Wu, Shu-Qi; Liu, Cai-Ming; Cui, Ai-Li; Kou, Hui-Zhong

    2015-09-21

    Two cyano- and phenoxo-bridged octanuclear complexes ZnDyCo (complex ) and ZnDyCr (complex ) with diamagnetic Zn(ii) and Co(iii) are reported. Dy(iii) is surrounded by nine oxygen atoms of two [Zn(Me2valpn)] (Me2valpn(2-) = dianion of N,N'-2,2-dimethylpropylenebis(3-methoxysalicylideneimine)) and one water molecule. Magnetic studies reveal that both exhibit single-ion magnet (SIM) behavior with the energy barrier of 85.9 K for complex and 100.9 K for complex .

  20. X-ray photoelectron spectroscopy and magnetism of AlDyNi, AlDyNi{sub 4} and AlDy{sub 3}Ni{sub 8} compounds

    Energy Technology Data Exchange (ETDEWEB)

    Rednic, V; Coldea, M; Rednic, L; Pascut, L G; Pintea, S [Babes-Bolyai University, Faculty of Physics, 1 Mihail Kogalniceanu, 400084 Cluj-Napoca (Romania); Aldea, N [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Neumann, M, E-mail: vasile.rednic@itim-cj.r [University of Osnabrueck, Fachbereich Physik, 49069 Osnabrueck (Germany)

    2009-08-01

    The electronic and magnetic properties of AlDyNi, AlDyNi{sub 4} and AlDy{sub 3}Ni{sub 8} are studied using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), static and dynamic magnetic measurements. The three compounds AlDyNi, AlDyNi{sub 4} and AlDy{sub 3}Ni{sub 8} are single phases and crystallize in the Fe{sub 2}P, CaCu{sub 5} and CeNi{sub 3} structure types, respectively. All the investigated compounds order ferromagnetically below the corresponding Curie temperatures. The Curie temperature and the magnetic moments are 25 K and 6 {mu}{sub B}/f.u. for AlDyNi, 14 K and 6.9 {mu}{sub B}/f.u. for AlDyNi{sub 4} and 22K and 19.2 {mu}{sub B}/f.u. for AlDy{sub 3}Ni{sub 8}. At high temperature the magnetic susceptibility obey the Curie-Weiss law. The paramagnetic Curie temperature and the effective magnetic moments are 30K and 10.88 {mu}{sub B}/f.u. for AlDyNi, 28 K and 10.94 {mu}{sub B}/f.u. for AlDyNi{sub 4} and 18 K and 18.33 {mu}{sub B}/f.u. for AlDy{sub 3}Ni{sub 8}. XPS valence band and Ni 2p spectra indicated the presence of small magnetic moment on Ni sites in AlDy{sub 3}Ni{sub 8} and AlDyNi{sub 4}, and a complete filling of Ni 3d band in AlDyNi.

  1. Isothermal section at 850 °C of the Ti–Dy–Al system in the Ti–TiAl–DyAl{sub 2}–Dy region

    Energy Technology Data Exchange (ETDEWEB)

    Bulanova, M.; Fartushna, I., E-mail: juliefart@mail.ru; Meleshevich, K.; Samelyuk, A.

    2014-06-15

    Highlights: • By the character the isothermal section at 850 °C is practically similar to the solidus surface. • The phases α{sup l}, α{sub 2} and αDyAl{sub 2} define the character of phase equilibria. • Among all phases only (αDyAl{sub 2}) dissolves significant amount of third component. • The solubility of titanium in αDyAl{sub 2} is about 19 at.%. • The ternary compounds in the studied region were not found. - Abstract: Phase equilibria in the Ti–Dy–Al system in the Ti–TiAl–DyAl{sub 2}–Dy region at 850 °C were studied by the methods of X-ray diffraction, SEM and electron microprobe. The isothermal section at this temperature was constructed. The ternary compounds in the studied region were not found. The isothermal section at 850 °C is characterized by the three-phase regions α{sup l} + (αDy) + (Dy{sub 2}Al), α{sup l} + α{sub 2} + (Dy{sub 2}Al), α{sub 2} + (Dy{sub 2}Al) + (Dy{sub 3}Al{sub 2}), α{sub 2} + (Dy{sub 3}Al{sub 2}) + (αDyAl{sub 2}), (DyAl) + (αDyAl{sub 2}) + (Dy{sub 3}Al{sub 2}) and α{sub 2} + (αDyAl{sub 2}) + γ and appropriate two-phase areas.

  2. Pressure effect on ferroelectric properties of multiferroics RMn2O5, (R = Gd, Tm)

    Science.gov (United States)

    Poudel, Narayan; Gooch, Melissa; Lorenz, Bernd; Chu, Ching-Wu; Kim, Jaewook; Cheong, Sang-Wook

    The pressure effect on the ferroelectric properties of the multiferroics GdMn2O5 and TmMn2O5 is studied up to 18.2 kbar. Unlike in RMn2O5 (R= Tb, Ho, Y), no significant change in polarization is observed in TmMn2O5 up to 16.6 kbar . However, a new ferroelectric phase is observed in GdMn2O5 above a critical pressure, Pc = 10 kbar at higher temperature. Our result indicates that pressure decouples the Gd moment from the Mn spin system and splits the ferroelectric phase. Thermal expansion data shows a large increase of the c axis at the ambient-pressure ferroelectric transition. The pressure-induced contraction of the c lattice parameter is found to be the cause for splitting of ferroelectric phase by decoupling of two spin systems above Pc. The pressure-temperature phase diagram is derived based on dielectric and ferroelectric properties.

  3. Homogenization heat treatment of Mg-7.68Gd-4.88Y-1.32Nd-0.63Al-0.05Zr alloy

    Institute of Scientific and Technical Information of China (English)

    张国栋; 李兴刚; 马鸣龙; 李永军; 石国梁; 袁家伟; 张奎

    2014-01-01

    The microstructures and mechanical properties of the Mg-7.68Gd-4.88Y-1.32Nd-0.63Al-0.05Zr magnesium alloy were investigated both in the as-cast condition and after homogenization heat treatment from 535 to 555 ºC in the time range 0-48 h by op-tical microscopy, scanning electron microscopy and hardness measurement. The as-cast alloy consisted of α-Mg matrix, Mg5(Y0.5Gd0.5) phase which is a eutectic phase, strip of Al2(Y0.6Gd0.4) phase, little Al3Zr and Mg(Y3Gd) phase. With the increasing of homogenization temperature and time, the Mg5(Y0.5Gd0.5) phase was completely dissolved into the matrix. The Al2(Y0.6Gd0.4) phase was almost not dissolved which impeded grain boundaries motion making the grain size almost not changed in the process of ho-mogenization. The optimum homogenization condition was 545 ºC/16 h. The tensile strength increased, yield strength decreased and the plasticity improved obviously after 545 ºC/16 h homogenization treatment.

  4. Light and anoxia fading of Prussian blue dyed textiles

    National Research Council Canada - National Science Library

    Gervais, Claire; Languille, Marie-Angélique; Reguer, Solenn; Garnier, Chantal; Gillet, Martine

    2014-01-01

    .... Its stability upon exposure to light and anoxia remains difficult to apprehend. The present paper focuses on the relative influences of light, anoxia and type of substrate on the discoloration of Prussian blue dyed textiles...

  5. High-spin structure of neutron-rich Dy isotopes

    Indian Academy of Sciences (India)

    A Ansari; H L Yadav; M Kaushik; U R Jakhar

    2003-06-01

    In view of recent experimental progress on production and spectroscopy of neutron-rich isotopes of Dy with mass number = 166 and 168, we have made theoretical investigations on the structure of high spin states of 164-170Dy isotopes in the cranked Hartree–Fock–Bogoliubov (CHFB) theory employing a pairing+quadrupole+hexadecapole model interaction. With the increase of neutron number the rotation alignment of the proton orbitals dominates the structure at high spins, which is clearly reflected in the spin dependence of the rotational g-factors. A particularly striking feature is the difference in the spin-dependent properties of 166Dy as compared to that of 164Dy.

  6. Green Non-dyed Textile Innovation Alliance officially launched

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    June 29, the Green Non-dyed Textile Innovation Alliance was officially launched by the China Textile Information Center, Nationa Textile Product Development Center together with China Chemical Fiber Industry Association

  7. Scissors Mode in Gd Nuclei

    Directory of Open Access Journals (Sweden)

    Wu C.Y.

    2012-02-01

    Full Text Available Spectra of γ rays following neutron capture at isolated resonances of 6 stable Gd isotopes were measured with highly segmented BaF2 detector DANCE at the Los Alamos LANSCE spallation neutron source. The main emphasis was put on studying the γ-cascade decay of neutron resonances to get unique information on photon strength. An analysis of the accumulated γ-ray spectra within the extreme statistical model leads to an inescapable conclusion that scissors mode resonances are built not only on the ground-state, but also on excited levels in all product nuclei studied. The results on summed B(M1↑ strength and energy of the scissors mode are compared with systematics of scissors mode parameters for the ground-state transitions deduced from nuclear resonance fluorescence measurements. A specific feature of our experiments is the investigation of scissors mode of odd nuclei, for which the nuclear resonance fluorescence provides only limited information.

  8. Scissors Mode in Gd Nuclei

    Science.gov (United States)

    Kroll, J.; Baramsai, B.; Becker, J. A.; Bečvář, F.; Bredeweg, T. A.; Couture, A.; Chyzh, A.; Dashdorj, D.; Haight, R. C.; Jandel, M.; Krtička, M.; Mitchell, G. E.; O'Donnell, J. M.; Parker, W.; Rundberg, R. S.; Ullmann, J. L.; Vieira, G. J.; Walker, C. L.; Wilhelmy, J. B.; Wouters, J. M.; Wu, C. Y.

    2012-02-01

    Spectra of γ rays following neutron capture at isolated resonances of 6 stable Gd isotopes were measured with highly segmented BaF2 detector DANCE at the Los Alamos LANSCE spallation neutron source. The main emphasis was put on studying the γ-cascade decay of neutron resonances to get unique information on photon strength. An analysis of the accumulated γ-ray spectra within the extreme statistical model leads to an inescapable conclusion that scissors mode resonances are built not only on the ground-state, but also on excited levels in all product nuclei studied. The results on summed B(M1)↑ strength and energy of the scissors mode are compared with systematics of scissors mode parameters for the ground-state transitions deduced from nuclear resonance fluorescence measurements. A specific feature of our experiments is the investigation of scissors mode of odd nuclei, for which the nuclear resonance fluorescence provides only limited information.

  9. Influence of Tb substitution on low-field magnetocaloric effect in Gd5Si1.72Ge2.28 alloy

    Institute of Scientific and Technical Information of China (English)

    DENG Jian-qiu; ZHUANG Ying-hong; WANG Ri-chu; YANG Zhen; XU Bin

    2008-01-01

    The lattice parameters, magnetic phase transition, Curie temperature and magnetocaloric properties for (Gd1-xTbx)5Si1.72-Ge2.28 alloys with x = 0, 0.15, 0.20 and 0.25 were investigated by X-ray powder diffractometry and magnetization measurements. The results show that suitable partial substitution of Tb in Gd5Si1.72Ge2.28 compound remains the first-order magnetic-crystallographic transition and enhances the magnetic entropy change, although Tb substitution decreases the Curie temperature (Tc) of the compounds. The magnetic entropy change of (Gd1-xTbx)5Si1.72Ge2.28 alloys retains a large value in the low magnetic field of 1.0 T.The maximum magnetic entropy change for (Gd0.80Tb0.20)5Si1.72Ge2.28 alloy in the magnetic field from 0 to 1.0 T reaches 8.7 J/(kg·K),which is nearly 4 times as large as that of (Gd0.3Dy0.7)5Si4 compound (|△Smax| = 2.24 J/(kg·K), TC = 198 K).

  10. The Calculation of Ho Production by indirect Method and Preparation of Polymeric Microsphere for Radioembolisation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, K. H.; Kim, J. B.; Park, U. J.; Cho, E. H.; Nam, S. S.; Yoo, K. M.; Jang, K. D. [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The reactor-produced radiolanthanides have been essential for development of therapeutic radiopharmaceuticals because they emit proper beta energies to induce tumor necrosis. Some radiolanthanides are very useful in that they have the ability of simultaneous diagnosis and therapeutic effect. This nuclide with both capacities is called as theranostic nuclide. In general, radiolanthanides can be produced by (n,γ) and (n,γ)β reaction. Of the two reactions, (n,γ)β reaction-product, shows high specific activity which is important things to affect labeling yield, is suitable for preparing the radiophamaceuticals comprising the antibody or peptide. Some radiolanthanides show the good theranostic effect in that they have proper LET (Linear Energy Transfer) to induce apoptosis for cancer and gamma ray to use as a tracer for cancer diagnosis. Although Ho-166 has been studied for therapeutic purpose since early 1990, production has been limited to direct method. To inject Dy/Ho mixture into the microsphere, we first set-up the concepts which are prior metal-administration method and posterior administration method. The latter is shown in this paper. Metal inletting process was done by using alternating between vacuum and pressurization. To prevent the leak of metal ions from metal/microsphere hybrid, surface coating was done by using interfacial reaction between saline and THF contained Poly lactic acid. Surface coating is simply completed just swiveling the vial. All experiments in this study, we just only tested with cold state.

  11. Structural and magnetic properties of the Gd-based bulk metallic glasses GdFe2, GdCo2, and GdNi2 from first principles

    Science.gov (United States)

    Lizárraga, Raquel

    2016-11-01

    A structural and magnetic characterization of Gd-based bulk metallic glasses, GdFe2, GdCo2, and GdNi2, was performed. Models for the amorphous structures for two magnetic configurations, ferromagnetic and ferrimagnetic, were obtained by means of a first-principles-based method, the stochastic quenching. In all three cases, the ferrimagnetic configuration was energetically more stable than the ferromagnetic one, in perfect agreement with experiments. In the structural analysis, radial and angle distribution functions as well as calculations of bond lengths and average coordination numbers were included. Structural properties are in good agreement with experiments and do not depend on the magnetic configuration. The distribution of magnetic moments shows that amorphous GdFe2 and GdCo2 are both ferrimagnets, with antiparallel alignment of the magnetic moments of the two magnetic sublattices, whereas Ni nearly loses its magnetic moment in amorphous GdNi2, similar to the situation in its crystalline counterpart.

  12. Comparison of the sequence-dependent fluorescence of the cyanine dyes Cy3, Cy5, DyLight DY547 and DyLight DY647 on single-stranded DNA.

    Science.gov (United States)

    Kretschy, Nicole; Somoza, Mark M

    2014-01-01

    Cyanine dyes are commonly used for fluorescent labeling of DNA and RNA oligonucleotides in applications including qPCR, sequencing, fluorescence in situ hybridization, Förster resonance energy transfer, and labeling for microarray hybridization. Previous research has shown that the fluorescence efficiency of Cy3 and Cy5, covalently attached to the 5' end of single-stranded DNA, is strongly sequence dependent. Here, we show that DY547 and DY647, two alternative cyanine dyes that are becoming widely used for nucleic acid labeling, have a similar pattern of sequence-dependence, with adjacent purines resulting in higher intensity and adjacent cytosines resulting in lower intensity. Investigated over the range of all 1024 possible DNA 5mers, the intensities of Cy3 and Cy5 drop by ∼ 50% and ∼ 65% with respect to their maxima, respectively, whereas the intensities of DY547 and DY647 fall by ∼ 45% and ∼ 40%, respectively. The reduced magnitude of change of the fluorescence intensity of the DyLight dyes, particularly of DY647 in comparison with Cy5, suggests that these dyes are less likely to introduce sequence-dependent bias into experiments based on fluorescent labeling of nucleic acids.

  13. Comparison of the sequence-dependent fluorescence of the cyanine dyes Cy3, Cy5, DyLight DY547 and DyLight DY647 on single-stranded DNA.

    Directory of Open Access Journals (Sweden)

    Nicole Kretschy

    Full Text Available Cyanine dyes are commonly used for fluorescent labeling of DNA and RNA oligonucleotides in applications including qPCR, sequencing, fluorescence in situ hybridization, Förster resonance energy transfer, and labeling for microarray hybridization. Previous research has shown that the fluorescence efficiency of Cy3 and Cy5, covalently attached to the 5' end of single-stranded DNA, is strongly sequence dependent. Here, we show that DY547 and DY647, two alternative cyanine dyes that are becoming widely used for nucleic acid labeling, have a similar pattern of sequence-dependence, with adjacent purines resulting in higher intensity and adjacent cytosines resulting in lower intensity. Investigated over the range of all 1024 possible DNA 5mers, the intensities of Cy3 and Cy5 drop by ∼ 50% and ∼ 65% with respect to their maxima, respectively, whereas the intensities of DY547 and DY647 fall by ∼ 45% and ∼ 40%, respectively. The reduced magnitude of change of the fluorescence intensity of the DyLight dyes, particularly of DY647 in comparison with Cy5, suggests that these dyes are less likely to introduce sequence-dependent bias into experiments based on fluorescent labeling of nucleic acids.

  14. Lanthanide dinuclear complexes constructed from mixed oxygen-donor ligands: the effect of substituent positions of the neutral ligand on the magnetic dynamics in Dy analogues.

    Science.gov (United States)

    Zhu, Wen-Hua; Li, Shan; Gao, Chen; Xiong, Xia; Zhang, Yan; Liu, Li; Powell, Annie K; Gao, Song

    2016-03-21

    Two series of lanthanide dinuclear complexes with the general formulae, [Ln(n-PNO)(Bza)3(H2O)] {Bza = benzoic acid; n = 3, n-PNO = 3-picoline N-oxide, Dy(1) and Er(2); and n = 4, n-PNO = 4-picoline N-oxide, Nd(3), Eu(4), Gd(5), Tb(6), Dy(7), Er(8) and Y(9)} have been successfully synthesized by the hydrothermal method. Single-crystal X-ray diffraction experiments illustrate that the two series of compounds possess similar carboxylic ligand-bridged dinuclear structure and coordination geometry around the lanthanide ions despite the different methyl-substituent positions on the neutral ligand. Comparative studies of the Dy analogues in the static-field measurements reveal only a little difference with a small butterfly-shaped opening for complex 1 and a close hysteresis loop for 7 at 2.0 K. However, systematic investigations of the alternating-current (ac) measurements indicate that the different substituent positions of the picoline N-oxide ligand have a significant effect on the magnetic relaxation dynamics. A more substantial suppression of the quantum tunnelling of magnetization (QTM) effect and pronounced slow magnetic relaxation were observed in complex 7 as compared to 1 under both zero and a 1 kOe static field.

  15. Determination of Gd concentration profile in UO2-Gd2O3 fuel pellets

    CERN Document Server

    Tobia, D; Milano, J; Butera, A; Kempf, R; Bianchi, L; Kaufmann, F

    2014-01-01

    A transversal mapping of the Gd concentration was measured in UO2-Gd2O3 nuclear fuel pellets by electron paramagnetic resonance spectroscopy (EPR). The quantification was made from the comparison with a Gd2O3 reference sample. The nominal concentration in the pellets is UO2: 7.5 % Gd2O3. A concentration gradient was found, which indicates that the Gd2O3 amount diminishes towards the edges of the pellets. The concentration varies from (9.3 +/- 0.5)% in the center to (5.8 +/- 0.3)% in one of the edges. The method was found to be particularly suitable for the precise mapping of the distribution of Gd3+ ions in the UO2 matrix.

  16. The Unimolecular Decomposition and H Abstraction Reactions by HO and HO2 from n-Butanol

    Science.gov (United States)

    Moc, Jerzy; Black, Gráinne; Simmie, John M.; Curran, Henry J.

    2009-08-01

    By using correlated ab initio (MP2, CCSD(T)) and multi-level (G3, CBS-QB3) methods we have studied unimolecular and bimolecular reactions of n-butanol in the gas phase. The specific processes investigated include H2O elimination and hydrogen abstraction by the hydroxy (HO) and hydroperoxy (HO2) radicals from this alcohol.

  17. Delayed cutaneous wound closure in HO-2 deficient mice despite normal HO-1 expression

    NARCIS (Netherlands)

    Lundvig, D.M.S.; Scharstuhl, A.; Cremers, N.A.J.; Pennings, S.W.C.; Paske, J. Te; Rheden, R. van; Breda, C. van Run-van; Regan, R.F.; Russel, F.G.M.; Carels, C.E.L.; Maltha, J.C.; Wagener, F.A.D.T.G.

    2014-01-01

    Impaired wound healing can lead to scarring, and aesthetical and functional problems. The cytoprotective haem oxygenase (HO) enzymes degrade haem into iron, biliverdin and carbon monoxide. HO-1 deficient mice suffer from chronic inflammatory stress and delayed cutaneous wound healing, while corneal

  18. Demonstration of a hybrid Ho:YLF Ho:LuLF slab laser

    CSIR Research Space (South Africa)

    Esser, MJD

    2010-10-01

    Full Text Available The authors present a continuous-wave slab laser utilising both Ho:YLF and Ho:LuLF as laser gain media. 30 W of output power at 2 µm was demonstrated in a stable concave-plane resonator while 13 W was achieved in a hybrid stable...

  19. Delayed cutaneous wound closure in HO-2 deficient mice despite normal HO-1 expression

    NARCIS (Netherlands)

    Lundvig, D.M.S.; Scharstuhl, A.; Cremers, N.A.J.; Pennings, S.W.C.; Paske, J. Te; Rheden, R. van; Breda, C. van Run-van; Regan, R.F.; Russel, F.G.M.; Carels, C.E.L.; Maltha, J.C.; Wagener, F.A.D.T.G.

    2014-01-01

    Impaired wound healing can lead to scarring, and aesthetical and functional problems. The cytoprotective haem oxygenase (HO) enzymes degrade haem into iron, biliverdin and carbon monoxide. HO-1 deficient mice suffer from chronic inflammatory stress and delayed cutaneous wound healing, while corneal

  20. Temperature Sensing Above 1000 C Using Cr-Doped GdAlO3 Spin-Allowed Broadband Luminescence

    Science.gov (United States)

    Eldridge, Jeffrey I.; Chambers, Matthew D.

    2012-01-01

    Cr-doped GdAlO3 (Cr:GdAlO3) is shown to produce remarkably high-intensity spin-allowed broadband luminescence with sufficiently long decay times to make effective luminescence-decay-time based temperature measurements above 1000 C. This phosphor is therefore an attractive alternative to the much lower luminescence intensity rare-earth-doped thermographic phosphors that are typically utilized at these elevated temperatures. In particular, Cr:GdAlO3 will be preferred over rare-earth-doped phosphors, such as Dy:YAG, at temperatures up to 1200 C for intensity-starved situations when the much lower emission intensity from rare-earth-doped phosphors is insufficient for accurate temperature measurements in the presence of significant radiation background. While transition-metal-doped phosphors such as Cr:Al2O3 (ruby) are known to exhibit high luminescence intensity at low dopant concentrations, quenching due to nonradiative decay pathways competing with the (sup 2)E to (sup 4)A(sub 2) radiative transition (R line) has typically restricted their use for temperature sensing to below 600 C. Thermal quenching of the broadband (sup 4)T(sub 2) to (sup 4)A(sub 2) radiative transition from Cr:GdAlO3, however, is delayed until much higher temperatures (above 1000 C). This spin-allowed broadband emission persists to high temperatures because the lower-lying (sup 2)E energy level acts as a reservoir to thermally populate the higher shorter-lived (sup 4)T(sub 2) energy level and because the activation energy for nonradiative crossover relaxation from the (sup 4)T(sub 2) level to the (sup 4)A(sub 2) ground state is high. The strong crystal field associated with the tight bonding of the AlO6 octahedra in the GdAlO3 perovskite structure is responsible for this behavior.

  1. Magnetocaloric effect in Gd-based ferromagnet GdZn2

    Science.gov (United States)

    Matsumoto, Keisuke T.; Hiraoka, Koichi

    2017-02-01

    Magnetic properties and magnetocaloric effect of the Gd-based compound GdZn2 have been investigated. GdZn2 shows a ferromagnetic transition at TC = 85 K and spin-reorientation transition at TSR = 58 K. The maximum entropy change and relative cooling power (RCP) are estimated to be 11.5 J/K kg and 690 J/kg, respectively, for a magnetic field change of 7 T. The large value of RCP is suggested that GdZn2 is an attractive candidate for a low-temperature magnetic refrigerant.

  2. Phase equilibria in the Gd-Ni binary and Mg-Ni-Gd ternary systems

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Guanglong; Fei, Houjun [Central South Univ., Hunan (China). School of Materials Science and Engineering; Cui, Yu-Wen [Madrid Institute for Advanced Studies of Materials, Madrid (Spain); Zhang, Ligang [Central South Univ., Hunan (China). School of Materials Science and Engineering; Freiberg Univ. of Mining and Technology (Germany). Centre for Innovation Competence; Zheng, Feng; Liu, Libin; Jin, Zhanpeng [Central South Univ., Hunan (China). School of Materials Science and Engineering; Scientific Center of Phase Diagram and Materials Design and Preparation, Hunan (China)

    2012-10-15

    Phase equilibria of the Gd-Ni binary and Mg-Ni-Gd ternary systems were critically investigated using equilibrated alloys and differential scanning calorimeter measurements. The phase diagram of the Gd-Ni binary system was updated from scanning electron microscopy with energy-dispersive X-ray spectrometry, X-ray diffraction, and differential scanning calorimeter results obtained on binary samples over the entire composition range. Major changes made in the present work include the absence of the Gd{sub 3}Ni{sub 2} and GdNi{sub 4} compounds and the congruent melting point of the GdNi compound. An isothermal section of the Mg-Ni-Gd ternary system at 673K was constructed from the investigations on 22 ternary alloys. In total, six ternary compounds were identified in this work, three of which were observed to crystallize in the Cu{sub 4}MgSn ({tau}1), Mo{sub 2}FeB{sub 2} ({tau}2), and Ru{sub 4}Al{sub 3}B{sub 2}-type ({tau}3) structures, respectively. As in most of the Mg-rare-earth metal-transition metal ternary systems, a long-period-stacking ordered phase was identified to have an 18R structure and a melting temperature of 806K. Noticeable solid solubility of Ni in the Mg{sub 5}Gd and Mg{sub 3}Gd binary compounds was observed.

  3. Ferromagnetic Resonance in Gd/Co Multilayers

    Institute of Scientific and Technical Information of China (English)

    A. V. Svalov; V. O. Vas'kovskiy; J. M. Barandiaran; G. V. Kurlyandskaya; L. Lezama; J. Gutiérrez; N. G. Bebenin; D. Schmool

    2001-01-01

    Magnetometric and ferromagnetic resonance (MFR) measurements have been performed on the polycrystalline multilayered structure, [Gd(7.5 nm)/Co(3nm)]20. The temperature dependence of magnetization of the sample suggests a compensation temperature Tcomp in the region of 240K, implying that the Co and Gd layers are antiferromagnetically aligned. The FMR curves are strongly temperature dependent, particularly in the vicinity of Tcomp.

  4. On the optical absorption coefficient of Gd hydride thin films: coexistence of the Gd (GdH{sub 2}) and GdH{sub x} (GdH{sub 2+y}) phases

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, W E; Azofeifa, D E; Clark, N [Centro de Investigacion en Ciencias e IngenierIa de Materiales and Escuela de Fisica, Universidad de Costa Rica, 2060 San Jose (Costa Rica)], E-mail: william.vargascastro@ucr.ac.cr

    2009-01-07

    Electron beam evaporated Pd-capped Gd thin films were deposited on quartz substrates and subsequently hydrided. Transmittance spectra of these bilayer systems, under unpolarized normal illumination, were obtained and used in an inversion approach from which the spectral dependence of the effective optical constants is obtained. The optical absorption coefficient of the {beta}-phase GdH{sub x} (with 1 < x {<=} 2) is reported. The semiconductor GdH{sub 2+y} state (with 0 < y {<=} 1) is characterized in terms of the optical absorption coefficient and the optical gap. By assuming a granular morphology of the films, with some of the grains in the metal GdH{sub 2} phase and other grains covered with a transition layer containing the semiconducting GdH{sub 2+y} phase, the hydrogen concentration dependence of the optical gap is shown and the optical absorption edge of the stoichiometric {gamma}-phase GdH{sub 3} is reported.

  5. Syntheses, structures and magnetic properties of a family of one-dimensional M(Ⅱ)-lanthanide(Ⅲ) (M = Ni(Ⅱ) and Zn(Ⅱ)) coordination polymers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of 1D nickel(II)/zinc(II)-lanthanide(III) coordination polymers, [M(μ-L)2Ln(NO3)3]n·solvents (HL = bis(2-pyridylcarbonyl)amine; M = Ni, Ln = Gd (1·NiGd), Tb (2·NiTb), Dy (3·NiDy), Ho (4·NiHo), Y (5·NiY); M = Zn, Ln = Gd (6·ZnGd), Tb (7·ZnTb), Dy (8·ZnDy), Ho (9·ZnHo); solvents = H2O or H2O-ethanol), was synthesized and characterized. All of the complexes are isostructural at 293 K and crystallize in the orthorhombic space group Fddd. Magnetic measurements were performed on 1―9, where weak ferromagnetic interaction is found in 1·NiGd, ferromagnetic interaction in 2·NiTb and 3·NiDy, and antiferromagnetic interaction in 4·NiHo. A remarkable dc magnetic field dependence of ac susceptibilities was found in this series of complexes.

  6. Syntheses, structures and magnetic properties of a family of one-dimensional M(Ⅱ)-lanthanide(Ⅲ) (M =Ni(Ⅱ) and Zn(Ⅱ)) coordination polymers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen; ZHAO Fei; LIU Tao; GAO Song

    2007-01-01

    A series of 1D nickel(Ⅱ)/zinc(Ⅱ)-lanthanide(Ⅲ) coordination polymers, [M(μ-L)2Ln(NO3)3]n· solvents (HL =bis(2-pyridylcarbonyl)amine; M = Ni, Ln = Gd (1 · NiGd), Tb (2· NiTb), Dy (3· NiDy), Ho (4· NiHo), Y (5· NiY);M = Zn, Ln =Gd (6· ZnGd), Tb (7· ZnTb), Dy (8· ZnDy), Ho (9· ZnHo); solvents = H2O or H2O-ethanol), was synthesized and characterized. All of the complexes are isostructural at 293 K and crystallize in the orthorhombic space group Fddd. Magnetic measurements were performed on 1-9, where weak ferromagnetic interaction is found in 1 · NiGd, ferromagnetic interaction in 2·NiTb and 3·NiDy, and antiferromagnetic interaction in 4· NiHo. A remarkable dc magnetic field dependence of ac susceptibilities was found in this series of complexes.

  7. Data of evolutionary structure change: 1BKGC-1GD9A [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1BKGC-1GD9A 1BKG 1GD9 C A MRGLSRRVQAMKPSATVAVNAKALELRRQGVDLVALTAG...EPDFDTPEHVKEAARRALAQGKTKYAPPAGIPELREALAEKFRRENGLSVTP-EETIVTVGGKQALFNLFQAILDPGDEVIVLSPYWVSYPEMVRFAGGVVVEVETLP...528 1GD9 A 1GD9A 1GD9 A 1GD9A HIS CA 377 THR CA 466 1GD

  8. Influence of the rare earth concentration on the crystallization process of Fe-Dy-B amorphous alloys. Study of Fe74Dy6B20 and Fe70Dy10B20 alloys

    Science.gov (United States)

    Ravach, G.; Machizaud, F.; Teillet, J.; LeBreton, J. M.; Fnidiki, A.

    2000-04-01

    The crystallization behaviour of Fe74 Dy6 B20 and Fe70 Dy10 B20 amorphous alloys was carefully investigated by differential scanning calorimetry, Mössbauer spectrometry and x-ray diffraction up to 800 °C. Calorimetric studies were performed in limited temperature ranges that were progressively extended. For Fe74 Dy6 B20 , after partial crystallization into the tetragonal Fe3 B compound, the remaining amorphous part segregates into two amorphous `phases', respectively enriched and impoverished in dysprosium. Tetragonal Fe3 B further transforms into orthorhombic Fe3 B. Metastable Dy3 Fe62 B14 compound then forms from the Dy-impoverished amorphous fraction, and subsequent crystallization of the Dy1 + icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="MIDDLE"/> Fe4 B4 phase occurs in the Dy-enriched fraction. Finally, Dy3 Fe62 B14 decomposes into bcc iron, Dy1 + icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="MIDDLE"/> Fe4 B4 and iron borides. The nature of the first crystallization product suggests the existence of local environments of t-Fe3 B type for this Dy concentration. The crystallization process of Fe70 Dy10 B20 strongly differs from that of Fe74 Dy6 B20 . Segregation phenomena occur in the amorphous state prior to any crystallization. If the nature of the first crystallization product is assumed to be correlated with short-range order in the amorphous state, our results suggest that the local environments differ from those of Fe74 Dy6 B20 , as they probably involve dysprosium atoms. This behaviour would agree with a previous Mössbauer study performed on the as-quenched amorphous alloys, providing evidence for a structural modification of the iron environments in the rare earth concentration range 8-9 at.%.

  9. Evaluation of Gd and Gd{sup 159} as new approaches for cancer treatment

    Energy Technology Data Exchange (ETDEWEB)

    Galvao, I.; Neves, M.J., E-mail: nevesmj@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Grupo de Desenvolvimento de Radiofarmacos; Santos, R.G., E-mail: santosr@cdtn.br [Instituto Nacional de Ciencia e Tecnologia em Medicina Molecular (INCT-MM), Belo Horizonte, MG (Brazil)

    2011-07-01

    Metal compounds have shown many biological activities and have been successfully used as anticancer agents such cisplatin. Actually gadolinium (Gd) complexed with a porphyrin Motexafin (MGd) has been investigated as redox-active compound for treatment of cancer. 1{sup 59G}d decays by beta emission with an energy of 970 keV and half-life of 18.59 hours. The de-excitation can be via gamma ray and internal conversion electron emission followed by auger electrons and x rays. Considering all of this 1{sup 59G}d could be a interesting radionuclide to be as a radio therapeutical agent. The aims of this works were to evaluate the cytotoxicity of Gd and 1{sup 59G}d on malignant brain tumors such as glioblastoma multiform, the most frequent brain tumors which has a very poor prognosis. For this purpose, it was used human glioblastoma cell lines T98 (mutant p53) and U87 (wild-type p53) to investigate the cytotoxicity of gadolinium on cell metabolism by MTT assay and also morphological changes, chromatin condensation by DAPI assay and ROS generation. Gadolinium was able to decrease cell viability, the cells presented morphological changes like round shapes and blebs formation after cell treatment with 5x10{sup -6}M of Gd. Nuclear changing and ROS generation occurred in a dose dependent way indicating the cytotoxic effect of Gd. Treatment with 1{sup 59G}d increased all of changes observed with treatment with Gd. These results state for an additive effect of metal toxicity and radioactivity inducing ROS generation as the main mechanism of anti tumoral action of 1{sup 59G}d. The results obtained indicated that the radioactive analogues of Gd have increased cytotoxic effects and gadolinium can be a metal of choice for development of new drugs for cancer treatment. (author)

  10. Polytypic phase formation in DyAl3 by rapid solidification

    Science.gov (United States)

    Xu, Yan; Altounian, Z.; Muir, W. B.

    1991-01-01

    Amorphous ribbons of AlxDy100-x, 93≳x≳85, were obtained by melt spinning. During crystallization, in addition to Al, four different metastable crystalline phases of DyAl3 were observed. These phases are, in order of appearance, the high-pressure face-centered cubic phase, γ-DyAl3 and three polytypic rhombohedral phases, β-DyAl3, β'-DyAl3, and α'-DyAl3. It is the first time that the β' phase in rare-earth trialuminides and the α' phase in Dy-Al alloy system have been observed. It is shown that all these phases are associated with the polytypic packing of the hexagonal DyAl3 atomic layers. The relative stability of the phases is found to be related to the hexagonal to cubic stacking ratio in the structure.

  11. Isothermal section of Dy-Zr-Si ternary system at 773 K

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The isothermal section of the phase diagram of the Dy-Zr-Si ternary system at 773 K was determined by X-ray diffraction (XRD) analysis, metallographic analysis, and scanning electron microscopy (SEM) with energy-dispersive spectrometer (EDS) analysis. The isothermal section consists of 13 single-phase regions, 23 two-phase regions, and 11 three-phase regions. The solubilities of Zr in Dy, Dy5Si4, Dy5Si3, DySi, DySi2, DySi1.67, and Dy in Zr, Zr2Si, Zr3Si2, Zr5Si4, ZrSi, and ZrSi2 were determined at 773 K.

  12. 75 FR 52534 - Su Van Ho: Debarment Order

    Science.gov (United States)

    2010-08-26

    ... Salmonella bacteria, with verification of such exportation or destruction by FDA. Mr. Ho concealed and... with Salmonella bacteria. As a result of his conviction, on June 10, 2010, FDA sent Mr. Ho a notice...

  13. Conversion of homothallic yeast to heterothallism trough HO gene disruption

    CSIR Research Space (South Africa)

    Van Zyl, WH

    1993-04-01

    Full Text Available A simple method was developed for the conversion of homothallic Saccharomyces cerevisiae yeaststrains to heterothallism through HO gene disruption. An integrative ho:: neo disrupted allele was constructed by cloning a dominant selectable marker...

  14. Reinvestigation of the Cd-Gd phase diagram.

    Science.gov (United States)

    Reichmann, Thomas L; Ipser, Herbert

    2014-12-25

    The complete Cd-Gd equilibrium phase diagram was investigated by a combination of powder-XRD, SEM and DTA. All previously reported phases, i.e., CdGd, Cd2Gd, Cd3Gd, Cd45Gd11, Cd58Gd13, and Cd6Gd, could be confirmed. In addition, a new intermetallic compound with a stoichiometric composition corresponding to "Cd8Gd" was found to exist. It was obtained that "Cd8Gd" decomposes peritectically at 465 °C. Homogeneity ranges of all intermetallic compounds were determined at distinct temperatures. In addition, the maximum solubilities of Cd in the low- and high-temperature modifications of Gd were determined precisely as 4.6 and 22.6 at.%, respectively. All invariant reaction temperatures (with the exception of the formation of Cd58Gd13) as well as liquidus temperatures were determined, most probably, Cd58Gd13 is formed in a peritectoid reaction from Cd45Gd11 and Cd6Gd at a temperature below 700 °C.

  15. Spin Waves in Ho2Co17

    DEFF Research Database (Denmark)

    Clausen, Kurt Nørgaard; Lebech, Bente

    1980-01-01

    Spin wave excitations in a single crystal of Ho2Co17 have been studied at 4.8 and 78 K. The results are discussed in terms of a linear spin wave model. At 78 K both ground state and excited state spin waves are observed.......Spin wave excitations in a single crystal of Ho2Co17 have been studied at 4.8 and 78 K. The results are discussed in terms of a linear spin wave model. At 78 K both ground state and excited state spin waves are observed....

  16. Giant magnetocaloric effect in Gd5(Si2Ge2 alloy with low purity Gd

    Directory of Open Access Journals (Sweden)

    Cleber Santiago Alves

    2004-12-01

    Full Text Available Gd5(Ge1-xSi x, x < 4 based alloys are potential candidates for magnetic refrigeration in the range ~20 - ~290 K. However, one of the greatest obstacles for the use of that technology in large scale is the utilization of high pure Gd metal (99.99 wt. (% to produce the GdGeSi alloys, since the impurity elements decrease the intensity of the magnetocaloric effect (EMC¹. In this work, we prove that annealing of the Gd5Ge2Si2 can promote remarkable values for the EMC in comparison to those obtained for the alloy with high pure Gd. Also, the as cast alloy and the annealed alloy are not monophasic, but have at least two crystalline phases in their microstructure. Results for X-ray analysis, optical and electronic microscopy and magnetization measurements are reported.

  17. Thermodynamic Optimization of DyCl3 -NaCl System

    Institute of Scientific and Technical Information of China (English)

    叶信宇; 孙益民; 张静; 谈君君

    2005-01-01

    In this paper, the phase diagram of the DyCl3 -NaCl system is optimized and calculated with CALPHAD ( calculation of phase diagram ) technology. A set of thermodynamic functions of compounds Na3 DyCl6, NaDyCl4, and NaDY2 Cl7 have been optimized and calculated based on an interactive computer-assisted analysis. The optimized thermodynamic parameters, calculated phase diagram and experimental phase diagram are thermodynamically serf-consistent.

  18. Investigations of the effect of nonmagnetic Ca substitution for magnetic Dy on spin-freezing in Dy2Ti2O7

    Science.gov (United States)

    Anand, V. K.; Tennant, D. A.; Lake, B.

    2015-11-01

    Physical properties of partially Ca substituted hole-doped Dy2Ti2O7 have been investigated by ac magnetic susceptibility {χ\\text{ac}}(T) , dc magnetic susceptibility χ (T) , isothermal magnetization M(H) and heat capacity {{C}\\text{p}}(T) measurements on Dy1.8Ca0.2Ti2O7. The spin-ice system Dy2Ti2O7 exhibits a spin-glass type freezing behavior near 16 K. Our frequency dependent {χ\\text{ac}}(T) data of Dy1.8Ca0.2Ti2O7 show that the spin-freezing behavior is significantly influenced by Ca substitution. The effect of partial nonmagnetic Ca2+ substitution for magnetic Dy3+ is similar to the previous study on nonmagnetic isovalent Y3+ substituted Dy2-x Y x Ti2O7 (for low levels of dilution), however the suppression of spin-freezing behavior is substantially stronger for Ca than Y. The Cole-Cole plot analysis reveals semicircular character and a single relaxation mode in Dy1.8Ca0.2Ti2O7 as for Dy2Ti2O7. No noticeable change in the insulating behavior of Dy2Ti2O7 results from the holes produced by 10% Ca2+ substitution for Dy3+ ions.

  19. The crucial role of Mn spiral spin order in stabilizing the Dy-Mn exchange striction in multiferroic DyMnO3.

    Science.gov (United States)

    Wang, H W; Li, C L; Yuan, S L; Wang, J F; Lu, C L; Liu, J-M

    2017-02-01

    DyMnO3 hosts the less addressed duality of multiferroicity, owing to the Dy-Mn exchange striction and inverse Dzyaloshinskii-Moriya interaction between Mn spin pairs. Although the duality in DyMnO3 has been discussed earlier, there remains a question whether the Mn magnetic sublattice is necessarily multiferroic for generating the Dy-Mn exchange striction. In this work, we investigate the multiferroicity of Dy(Mn1-xFex)O3 (0 ≤ x ≤ 0.1) through detailed magnetic and ferroelectric characterization. It is found that Fe-doping continuously suppresses the independent Dy spin order but instead promotes the Dy-Mn(Fe) coupling. This coupling benefits the Dy-Mn(Fe) exchange striction which remarkably enhances the ferroelectric polarization at a low doping level (x ≤ 0.015), beyond which the Mn spiral spin order breaks down leading to collapse of the macroscopic polarization at x ≥ 0.05. This work discloses the crucial role of Mn spiral spin order in stabilizing the Dy-Mn exchange striction and thus highlights the duality of multiferroicity in DyMnO3.

  20. Tetranuclear {Co(II)2Co(III)2}, Octanuclear {Co(II)4Co(III)4}, and Hexanuclear {Co(III)3Dy(III)3} Pivalate Clusters: Synthesis, Magnetic Characterization, and Theoretical Modeling.

    Science.gov (United States)

    Radu, Ioana; Kravtsov, Victor Ch; Ostrovsky, Serghei M; Reu, Oleg S; Krämer, Karl; Decurtins, Silvio; Liu, Shi-Xia; Klokishner, Sophia I; Baca, Svetlana G

    2017-03-06

    New tetranuclear and octanuclear mixed-valent cobalt(II/III) pivalate clusters, namely, [NaCo4(O2CCMe3)6(HO2CCMe3)2(teaH)2(N3)]·2H2O (in two polymorphic modifications, 1 and 1a) and [Co8(O2CCMe3)10(teaH)4(N3)](Me3CCO2)·MeCN·H2O (2) have been synthesized by ultrasonic treatment of a dinuclear cobalt(II) pivalate precursor with sodium azide and triethanolamine (teaH3) ligand in acetonitrile. The use of Dy(NO3)3·6H2O in a similar reaction led to the precipitation of a tetranuclear [NaCo4(O2CCMe3)4(teaH)2(N3)(NO3)2(H2O)2]·H2O (3) cluster and a heterometallic hexanuclear [Co3Dy3(OH)4(O2CCMe3)6(teaH)3(H2O)3](NO3)2·H2O (4) cluster. Single-crystal X-ray analysis showed that 1 (1a) and 3 consist of a tetranuclear pivalate/teaH3 mixed-ligand cluster [Co(II)2Co(III)2(O2CCMe3)4(teaH)2(N3)](+) decorated with sodium pivalates [Na(O2CCMe3)2(HO2CCMe3)2](-) (1 or 1a) or sodium nitrates [Na(NO3)2](-) (3) to form a square-pyramidal assembly. In 2, the cationic [Co8(O2CCMe3)10(teaH)4(N3)](+) cluster comprises a mixed-valent {Co(II)4Co(III)4} core encapsulated by an azide, 4 teaH(2-) alcoholamine ligands, and 10 bridging pivalates. Remarkably, in this core, the μ4-N3(-) ligand joins all four Co(II) atoms. The heterometallic hexanuclear compound 4 consists of a cationic [Co(III)3Dy(III)3(OH)4(O2CCMe3)6(teaH)3(H2O)3](2+) cluster, two NO3(-) anions, and a crystallization water molecule. The arrangement of metal atoms in 4 can be approximated as the assembly of a smaller equilateral triangle defined by three Dy sites with a Dy···Dy distance of 3.9 Å and a larger triangle formed by Co sites [Co···Co, 6.1-6.2 Å]. The interpretation of the magnetic properties of clusters 2-4 was performed in the framework of theoretical models, taking into account the structural peculiarities of clusters and their energy spectra. The behavior of clusters 2 and 3 containing Co(II) ions with orbitally nondegenerate ground states is determined by the zero-field splitting of these states and

  1. Switching the conductance of Dy nanocontacts by magnetostriction.

    Science.gov (United States)

    Müller, Marc; Montbrun, Richard; Marz, Michael; Fritsch, Veronika; Sürgers, Christoph; v Löhneysen, Hilbert

    2011-02-09

    The electrical conductance G of mechanical break-junctions fabricated from the rare-earth metal dysprosium has been investigated at 4.2 K where Dy is in the ferromagnetic state. In addition to the usual variation of the conductance while breaking the wire mechanically, the conductance can be changed reproducibly by variation of the magnetic field H, due to the large magnetostriction of Dy. For a number of contacts, we observe discrete changes in G(H) in the range of several G(0) = 2e(2)/h. The behavior of G(H) and its angular dependence can be quantitatively understood by taking into account the magnetostrictive properties of Dy. This realization of a magnetostrictive few-atom switch demonstrates the possibility of reproducibly tuning the conductance of magnetic nanocontacts by a magnetic field.

  2. Magnetization of Gd diffused YBa2Cu3O7-x superconductor:Experiment and theory

    Institute of Scientific and Technical Information of China (English)

    F.Inanir; S.Yildiz; K.Ozturk; S.Celebi

    2013-01-01

    The magnetization of Gd diffused YBa2Cu3OT-x is measured by a vibrating sample magnetometer (VSM) at selected temperatures (5,25,50,77 K).The experimental results for the magnetization are analyzed in the critical state framework involving Kim-Anderson field dependence Jc(H) =Jc0/(1 + |H|/Ho)n of critical current density and equilibrium magnetization Meq.It is found that the inclusion of the equilibrium magnetization becomes more important at higher temperatures.At 77 K,the shape of the isothermal M-H hysteresis curve is governed by the equilibrium magnetization.Some superconducting parameters are determined by fitting the calculated curves to the experimental data.

  3. Gd-enhanced subtraction MR venography

    Energy Technology Data Exchange (ETDEWEB)

    Hoshi, Toshiko; Hachiya, Takashi; Kanauchi, Tetsu; Hando, Yumiko; Homma, Tsuguo [Saitama Cardiovascular and Respiratory Center, Konan (Japan)

    1999-10-01

    We succeeded in distinctly imaging the calf veins using Gd-enhanced subtraction MR venography (Gd SMRV). Gd SMRV was performed in 15 normal legs, 33 varicose legs and 22 legs with suspected deep venous thrombosis. Conventional venography was performed in 46 legs in all. The deep veins of the calf, greater saphenous vein, and intramuscular veins had high rates of demonstration in normal legs and varicose legs (84, 100%, 87, 97%, 67, 73%). The varices were also well demonstrated (100%). When Gd SMRV was compared with conventional venography in terms of diagnosis of calf venous thrombosis, the sensitivity of this method was 100%, specificity was 92% and accuracy was 93%. We found high intensity thrombi on precontrast images in most cases, a finding that was important for the diagnosis of local thrombi. This method was non-invasive and was able to clearly visualize veins in the calf. We concluded that Gd SMRV was useful for calf venous disease, especially calf venous thrombosis. (author)

  4. Low temperature magnetic properties of DyPdBi

    Science.gov (United States)

    Mukhopadhyay, A.; Chowki, S.; Mohapatra, N.

    2016-05-01

    We report the results of dc magnetization measurements in the ternary half -Heuslar alloy, DyPdBi which crystallizes in a non centrosymmetric MgAgAs type fcc structure. DyPdBi undergoes a long range antiferromagnetic type ordering below 4.0 K as inferred from the temperature dependence of dc magnetic susceptibility. Another noteworthy observation is the field induced metamagnetic transition below TN, further suggestes that the order-order field induced transition as a first order phase transition.

  5. Optical studies of Dy-doped Bi-2212.

    Science.gov (United States)

    Gasparov, L.; Pekarek, T.; Tanner, D.; Berger, H.; Forro, L.; Margaritondo, G.

    2001-03-01

    We present temperature-dependent reflectance measurements for Dy doped Bi-2212 based single crystals with T_c=3D 55 and 70K in the frequency range from 100 to 40,000 cm-1 (0.012--5 eV). The material is interesting on account of a weak ferromagnetic-type magnetization behavior. The optical conductivity is obtained by Kramers-Kronig analysis. We compare Dy-doped crystals with other previously measured Bi-2212 based crystals by analyzing optical conductivity in the framework of a two-fluid approach. This approach allows us to follow correlations between superfluid density and superconducting transition temperature of the materials. =00

  6. Thermoluminescent characteristics of nano-structure hydroxyapatite:Dy

    Energy Technology Data Exchange (ETDEWEB)

    Ziaie, F. [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School; Moein, N. Farhadi [Islamic Azad Univ. (Iran, Islamic Republic of). Central Tehran Branch; Shafaei, M. [Islamic Azad Univ. (Iran, Islamic Republic of). Science and Research Branch

    2014-12-15

    The thermoluminescence response of Dysprosium doped hydroxyapatite samples with different mol percentage of 0.5, 1 and 2 were studied and compared with the pure hydroxyapatite. The samples were objected to {sup 60}Co gamma rays irradiation with doses of 100 mGy to 10 Gy. The main peak in the sample glow curves were obtained at 310 C. The sensitivity of the 1 mol% Dy doped hydroxyapatite samples show the highest thermoluminescence response. Fading behavior of the irradiated samples was also studied. The experimental results show that the synthetic Dy-doped hydroxyapatite obtained by the hydrolysis method may be used in gamma radiation dosimetry.

  7. Optical properties of lead borate glasses containing Dy3+ ions

    Science.gov (United States)

    Pisarska, Joanna

    2009-07-01

    Optical properties of lead borate glasses containing Dy3+ ions were examined using absorption and luminescence measurements and theoretical calculations based on the Judd-Ofelt framework and the Inokuti-Hirayama model. The luminescence spectra show two characteristic bands at 480 and 573 nm, which are due to 4F9/2-6H15/2 (blue) and 4F9/2-6H13/2 (yellow) transitions of trivalent Dy3+ ions. The yellow/blue luminescence and its decay were analyzed as a function of activator concentration.

  8. Defective muscle basement membrane and lack of M-laminin in the dystrophic dy/dy mouse

    DEFF Research Database (Denmark)

    Xu, H; Christmas, P; Wu, X R;

    1994-01-01

    M-laminin is a major member of the laminin family of basement membrane proteins. It is prominently expressed in striated muscle and peripheral nerve. M-laminin is deficient in patients with the autosomal recessive Fukuyama congenital muscular dystrophy but is normal in patients with the sex......-linked Duchenne and Becker muscular dystrophies. We have examined M-laminin expression in mice with autosomal recessive muscular dystrophy caused by the mutation dy. The heavy chain of M-laminin was undetectable in skeletal muscle, heart muscle, and peripheral nerve by immunofluorescence and immunoblotting...... in homozygous dystrophic dy/dy mice but was normal in heterozygous and wild-type nondystrophic mice. Immunofluorescence confirmed the presence of other major basement membrane proteins in the dystrophic mice. Very low levels of M-laminin heavy chain mRNA were detected by Northern blotting of muscle and heart...

  9. Magnetic and Electronic Properties of R3Ni7B2 Compounds where R = Dy, Ho, Er

    Science.gov (United States)

    Bucur, N.; Vlaic, P.; Burzo, E.

    2007-04-01

    Band structure calculations show the presence of small magnetic moments at Ni sites. Magnetic measurements at 4.2 K evidenced a relative high anisotropy. Magnetic behavior of nickel is analyzed in spin fluctuation model.

  10. Variations of magnetocaloric effect and magnetoresistance across RCuGe (R=Tb, Dy, Ho, Er) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Sachin; Suresh, K.G., E-mail: suresh@phy.iitb.ac.in

    2015-10-01

    RCuGe (R=Tb–Er) compounds have been studied by structural, magnetic, magnetocaloric and magnetotransport measurements. All these compounds are iso-structural and show antiferromagnetic ordering below their Néel temperatures (T{sub N}). Except TbCuGe, all the studied compounds show large magnetocaloric effect (MCE), arising due to the field induced metamagnetic transition. They also show a sign reversal of magnetoresistance (MR) with change in temperature or field. The non-monotonic variation of the magnitude of MR is attributed to the competing effects of Lorentz force, changes in the spin disorder scattering and the spin fluctuations. - Highlights: • RCuGe (R=Tb–Er) compounds show low temperature antiferromagnetic ordering. • All compounds show field induced metamagnetic transitions. • These compounds show large magnetocaloric effect and magnetoresistance.

  11. X-ray resonant magnetic scattering investigations of hexagonal multiferroics RMnO3 (R = Dy, Ho, Er)

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, Shibabrata [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Electricity and magnetism were unified into a common subject by James Clerk Maxwell in the nineteenth century yielding the electromagnetic theory. Four equations govern the dynamics of electric charges and magnetic fields, commonly known as Maxwell's equations. Maxwell's equations demonstrate that an accelerated charged particle can produce magnetic fields and a time varying magnetic field can induce a voltage - thereby linking the two phenomena. However, in solids, electric and magnetic ordering are most often considered separately and usually with good reason: the electric charges of electrons and ions are responsible for the charge effects, whereas the electron spin governs magnetic properties.

  12. Rekonstrukce historického vozidla

    OpenAIRE

    Richter, Tomáš

    2010-01-01

    Cílem této bakalářské práce je navrhnout postup rekonstrukce historického vozidla a dokumentovat jednotlivé etapy. This bachelor’s thesis offers process of redesign veteran motor car and documents particular stages. A

  13. Saigon-Ho Chi Minh City

    NARCIS (Netherlands)

    Nguyen, T.B.; Samsura, D.A.A.; Krabben, E. van der; Le, A.-D.

    2016-01-01

    Ho Chi Minh City (HCMC) has existed for over three centuries and has developed into the financial capital and most important economic hub of Vietnam. This profile outlines the history of HCMC's development and its impact on current conditions and physical structure of the city. The paper analyzes so

  14. Luminescence investigation of Dy2O2S and Dy2O2SO4 obtained by thermal decomposition of sulfate hydrate

    Institute of Scientific and Technical Information of China (English)

    RV Rodrigues; L Marciniak; LU Khan; JR Matos; HF Brito; W Strk

    2016-01-01

    The yellow emitting dysprosium oxysulfide (Dy2O2S) and dysprosium oxysulfate (Dy2O2SO4) compounds were prepared from the thermal decomposition of hydrated dysprosium sulphate. The materials were characterized by using thermogravimetry (TG/DTG), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopies. The thermal stability temperatures at around 1151 and 1313 K were determined for the Dy2O2S and Dy2O2SO4 materials, respectively. The photolumines-cence properties of the dysprosium oxysulfide were investigated, showing narrow emission bands assigned to the 4F9/2→6HJ intracon-figurational transitions of the Dy3+ion. The yellow emission color of this phosphor suggests that the Dy2O2S is a promising material for applications in LEDs.

  15. Formation of ganglioside GD1b-lactone in rat brain from intracisternally administered GD1b

    Energy Technology Data Exchange (ETDEWEB)

    Riboni, L.; Ghidoni, R.; Tettamanti, G.

    1989-05-01

    The presence of ganglioside GD1b, in lactone form GD1b-L, was ascertained in rat brain. The possible formation of GD1b-L from GD1b in brain was explored by the intracisternal injection of GD1b, /sup 3/H-labelled at the level of the terminal galactose. This was followed by recognition of the radioactive gangliosides formed at different times (1, 3, and 7 days) after injection. Whereas at 0 time after injection the only radioactive ganglioside was GD1b, after 1, 3, and 7 days other radioactive gangliosides were also found, thus indicating GD1b penetration into the brain tissue, followed by metabolic processing. Besides GD1b, the following radioactive gangliosides were recognized: GM1 and GM2, derived from GD1b degradation; GT1b, formed by the direct sialylation of GD1b; and GD1b-L, produced by metabolic lactonization. The radioactivity carried by GD1b-L was maximal 3 days after injection; its time course was different from that of the other gangliosides, suggesting that the process of lactonization is separate from that of both degradation and glycosylation. Under the same experimental conditions, some radioactive gangliosides also appeared in the liver, although in much smaller amounts than in brain. Radioactive GD1b-L could not be detected in liver, thus indicating that metabolic lactonization is a tissue- or organ-specific process.

  16. Electrochemical performance of alloys Ho_5Fe_3Co_(12) and Ho_(33.3)Co_(66.7)

    Institute of Scientific and Technical Information of China (English)

    赵允红; 何维; 张永志; 曾令民

    2010-01-01

    Alloys with composition Ho5Fe3Co12 and Ho33.3Co66.7 were prepared and examined by X-ray diffractometer and automatic battery testing instrument. The electrochemical properties of these alloys such as discharge capacity, cycling performance and high rate dischargeability were investigated by battery testing instruments in alkaline electrolyte. A comparison of the electrochemical performance of the Ho5Fe3Co12 and Ho33.3Co66.7 alloys revealed that alloy Ho5Fe3Co12 possessed a better electrochemical performance...

  17. Influence of Dy content on the structure and giant magnetoresistance of Dy x(Co 40Ag 60) 100- x granular films

    Science.gov (United States)

    Gang, Cheng; Xiaofei, Wu; Wei, Chen; Shengdong, Geng; Lin, Li; Zhengfei, Gu

    2012-01-01

    Dyx(Co40Ag60)100-x (x = 0, 0.7, 1.4, 2.1, 2.8, 3.5) granular films have been prepared by DC magneto controlled sputtering method. The XRD data indicated that Dy element restrained the (1 1 1) plane preferential orientation. Magnetic measurements indicated that the average size of magnetic particles increased with the increasing in Dy content. For relatively low addition Dy to CoAg granular films, Dy element can enhance GMR value as a maximum value of the GMR value ∼-18.1% at x = 0.7.

  18. Studies of normal deformation in {sup 151}Dy

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

    1995-08-01

    The wealth of data collected in the study of superdeformation in {sup 151}Dy allowed for new information to be obtained on the normally deformed structures in this nucleus. At high spin several new yrast states have been identified for the first time. They were associated with single-particle excitations. Surprisingly, a sequence was identified with energy spacings characteristic of a rotational band of normal ({beta}2 {approximately} 0.2) deformation. The bandhead spin appears to be 15/2{sup -} and the levels extend up to a spin of 87/2{sup -}. A clear backbend is present at intermediate spins. While a similar band based on a bandhead of 6{sup +} is known in {sup 152}Dy, calculations suggest that this collective prolate band should not be seen in {sup 151}Dy. In the experiment described earlier in this report that is aimed at determining the deformations associated with the SD bands in this nucleus and {sup 152}Dy, the deformation associated with this band will be determined. This will provide further insight into the origin of this band.

  19. Magnetoelastic vibration damping properties of TbDy alloys

    Science.gov (United States)

    Dooley, Jennifer A.; Good, Nathan R.; White, Christopher V.; Leland, Robert S.

    2003-03-01

    Damping of axial and bending mode vibrations in giant magnetoelastic polycrystalline TbDy alloys was studied at cryogenic temperatures. All specimens of TbDy were arc-melted in the proper composition ratio and dropped into a chilled copper mold. Additional treatments consisted of cold plane-rolling to induce crystallographic texture and then heat-treating to relieve internal stress. Mechanical hysteretic losses were measured at various strains, frequencies, and loading configurations down to 77 K. Both as-cast and textured polycrystalline TbDy samples were tested along with an aluminum specimen for comparison. Loss factors at multiple natural vibration frequencies of the samples were measured for axial modes. Larger damping rates were measured for axial mode vibrations than for bending mode vibrations, possibly reflecting the larger specimen volume contributing to magnetoelastic damping. At LN2 temperatures TbDy materials demonstrated η > 0.05 at 0.01 Hz and η > 0.1 at higher frequencies from 0.6-1.5 kHz.

  20. EST Table: DY231350 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available DY231350 EST02101 10/09/28 99 %/227 aa ref|NP_001037309.1| vitellogenin precursor [...s: Precursor dbj|BAA02444.1| vitellogenin precursor [Bombyx mori] dbj|BAA06397.1| vitellogenin [Bombyx mori

  1. Using polyvinyl chloride dyed with bromocresol purple in radiation dosimetry.

    Science.gov (United States)

    Kattan, Munzer; al Kassiri, Haroun; Daher, Yarob

    2011-02-01

    Polyvinyl chloride (PVC) dyed with bromocresol purple was investigated as a high-dose radiation dosimeter. The absorbance at 417 nm depends linearly on the dose below 50 kGy. The response depends neither on dose rate nor on the irradiation temperature. The effects of post-irradiation storage in the dark and in indirect sunlight are also discussed.

  2. Surface activation of dyed fabric for cellulase treatment.

    Science.gov (United States)

    Schimper, Christian B; Ibanescu, Constanta; Bechtold, Thomas

    2011-10-01

    Surface activation of fabric made from cellulose fibres, such as viscose, lyocell, modal fibres and cotton, can be achieved by printing of a concentrated NaOH-containing paste. From the concentration of reducing sugars formed in solution, an increase in intensity of the cellulase hydrolysis by a factor of six to eight was observed, which was mainly concentrated at the activated parts of the fabric surface. This method of local activation is of particular interest for modification of materials that have been dyed with special processes to attain an uneven distribution of dyestuff within the yarn cross-section, e.g., indigo ring-dyed denim yarn for jeans production. Fabrics made from regenerated cellulose fibres were used as model substrate to express the effects of surface activation on indigo-dyed material. Wash-down experiments on indigo-dyed denim demonstrated significant colour removal from the activated surface at low overall weight loss of 4-5%. The method is of relevance for a more eco-friendly processing of jeans in the garment industry.

  3. Determination of two reactive dyes concentration in dyed cotton fabric

    Directory of Open Access Journals (Sweden)

    Miljković Milena

    2012-01-01

    Full Text Available The purpose of this paper was to determine the unknown concentration of dichlortriazinyl reactive dyes, namely Reactive Yellow 22 and Reactive Blue 163, in dyed cotton fabric. The samples of cotton fabric were dyed individually with each dye as well as with a mixture of two dyes. The unknown concentrations of dyes were determined by measuring the corresponding reflectance values of dyed fabric samples and then using the relation between the concentration and reflectance values of the samples. The method set by Kubelka and Munk was used. The accuracy and repeatability of the concentrations determination were calculated by the statistical processing of the data obtained by measurements. Relative errors of individual determination of Reactive Yellow 22 and Reactive Blue 163 were 3.66% and 5.94% respectively. Relative errors in determination of Reactive Yellow 22 and Reactive Blue 163 in a mixture were 3.47% and 3.19% respectively. The results showed that reflectance spectrophotometry can be successfully used as the method for concentration determination of Reactive Yellow 22 and Reactive Blue 163 in dyed cotton fabric and can therefore be applied as the shade control method in dyeing.

  4. EST Table: DY230716 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available DY230716 EST01452 10/09/28 51 %/110 aa ref|XP_002427369.1| Integrator complex subun...it, putative [Pediculus humanus corporis] gb|EEB14631.1| Integrator complex subunit, putative [Pediculus hum

  5. EST Table: DY230676 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available x mori] dbj|BAA89306.1| Promoting Protein [Bombyx mori] 10/09/03 32 %/105 aa FBpp0237404|DvirGJ22987-PA 10/0...DY230676 EST01412 10/09/28 87 %/127 aa ref|NP_001036842.1| promoting protein [Bomby

  6. EST Table: DY231371 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available DY231371 EST02122 10/09/28 98 %/130 aa ref|NP_001040121.1| endothelial-monocyte act...ivating polypeptide II [Bombyx mori] gb|ABD36113.1| endothelial-monocyte activating polypeptide II [Bombyx m

  7. Viscosity, fission time scale and deformation of Dy-156

    NARCIS (Netherlands)

    van't Hof, G; Bacelar, JCS; Dioszegi, [No Value; Harakeh, MN; Hesselink, WHA; Kalantar-Nayestanaki, N; Kugler, A; van der Ploeg, H; Plompen, AJM; van Schagen, JPS

    1998-01-01

    In the fusion-fission reaction Ar-40 + Cd-116 --> Dy-156*, fission, at E-b = 216 MeV and 238 MeV, gamma-rays were measured in coincidence with fission fragments. The interpretation of the gamma-ray spectra is done with the help of a modified version of the statistical-model code CASCADE. The spectra

  8. Redetermination of Dy3Ni from single-crystal X-ray data

    Science.gov (United States)

    Levytskyy, Volodymyr; Babizhetskyy, Volodymyr; Kotur, Bohdan; Smetana, Volodymyr

    2013-01-01

    The classification of the title compound, tridysprosium nickel, into the Fe3C (or Al3Ni) structure type has been deduced from powder X-ray diffraction data with lattice parameters reported in a previous study [Lemaire & Paccard (1967 ▶). Bull. Soc. Fr. Mineral. Cristallogr. 40, 311–315]. The current re-investigation of Dy3Ni based on single-crystal X-ray data revealed atomic positional parameters and anisotropic displacement parameters with high precision. The asymmetric unit consists of two Dy and one Ni atoms. One Dy atom has site symmetry .m. (Wyckoff position 4c) and is surrounded by twelve Dy and three Ni atoms. The other Dy atom (site symmetry 1, 8d) has eleven Dy and three Ni atoms as neighbours, forming a distorted Frank–Kasper polyhedron. The coordination polyhedron of the Ni atom (.m., 4c) is a tricapped trigonal prism formed by nine Dy atoms. PMID:24454015

  9. Redetermination of Dy3Ni from single-crystal X-ray data

    Directory of Open Access Journals (Sweden)

    Volodymyr Levytskyy

    2013-11-01

    Full Text Available The classification of the title compound, tridysprosium nickel, into the Fe3C (or Al3Ni structure type has been deduced from powder X-ray diffraction data with lattice parameters reported in a previous study [Lemaire & Paccard (1967. Bull. Soc. Fr. Mineral. Cristallogr. 40, 311–315]. The current re-investigation of Dy3Ni based on single-crystal X-ray data revealed atomic positional parameters and anisotropic displacement parameters with high precision. The asymmetric unit consists of two Dy and one Ni atoms. One Dy atom has site symmetry .m. (Wyckoff position 4c and is surrounded by twelve Dy and three Ni atoms. The other Dy atom (site symmetry 1, 8d has eleven Dy and three Ni atoms as neighbours, forming a distorted Frank–Kasper polyhedron. The coordination polyhedron of the Ni atom (.m., 4c is a tricapped trigonal prism formed by nine Dy atoms.

  10. Reinvestigation of the Cd–Gd phase diagram

    Science.gov (United States)

    Reichmann, Thomas L.; Ipser, Herbert

    2014-01-01

    The complete Cd–Gd equilibrium phase diagram was investigated by a combination of powder-XRD, SEM and DTA. All previously reported phases, i.e., CdGd, Cd2Gd, Cd3Gd, Cd45Gd11, Cd58Gd13, and Cd6Gd, could be confirmed. In addition, a new intermetallic compound with a stoichiometric composition corresponding to “Cd8Gd” was found to exist. It was obtained that “Cd8Gd” decomposes peritectically at 465 °C. Homogeneity ranges of all intermetallic compounds were determined at distinct temperatures. In addition, the maximum solubilities of Cd in the low- and high-temperature modifications of Gd were determined precisely as 4.6 and 22.6 at.%, respectively. All invariant reaction temperatures (with the exception of the formation of Cd58Gd13) as well as liquidus temperatures were determined, most probably, Cd58Gd13 is formed in a peritectoid reaction from Cd45Gd11 and Cd6Gd at a temperature below 700 °C. PMID:25544803

  11. Pressure induced structural transformation in Gd2Ti2O7 and Gd2Zr2O7

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Haiyan [Pacific Northwest National Laboratory (PNNL); Weber, William J [ORNL

    2011-01-01

    Ab initio total energy calculations have been performed to study the phase stability of Gd2Ti2O7 and Gd2Zr2O7 pyrochlores over the pressure range from 0 to 60 GPa. Both compounds are unstable under pressure, and phase transformations to the defect-cotunnite structure are predicted. The phase transformation pressure of 43.6 GPa for Gd2Ti2O7 is considerably larger than the value of 13 GPa for Gd2Zr2O7, in good agreement with experiments. The decreased structural stability of Gd2Zr2O7 under pressure, relative to Gd2Ti2O7, is a consequence of the lower compressibility of the Zr O bond and the higher compressibility of the Gd O bond. In addition, the Gd 4f electrons are found to have only a small effect in determining the pressure induced phase transformation.

  12. Pressure induced structural transformation in Gd2Ti2O7 and Gd2Zr2O7

    Science.gov (United States)

    Xiao, H. Y.; Weber, W. J.

    2011-01-01

    Ab initio total energy calculations have been performed to study the phase stability of Gd2Ti2O7 and Gd2Zr2O7 pyrochlores over the pressure range from 0 to 60 GPa. Both compounds are unstable under pressure, and phase transformations to the defect-cotunnite structure are predicted. The phase transformation pressure of 43.6 GPa for Gd2Ti2O7 is considerably larger than the value of 13 GPa for Gd2Zr2O7, in good agreement with experiments. The decreased structural stability of Gd2Zr2O7 under pressure, relative to Gd2Ti2O7, is a consequence of the lower compressibility of the langZr-Orang bond and the higher compressibility of the langGd-Orang bond. In addition, the Gd 4f electrons are found to have only a small effect in determining the pressure induced phase transformation.

  13. Data of evolutionary structure change: 1AKMC-3GD5B [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1AKMC-3GD5B 1AKM 3GD5 C B SGFYHKHFLKLLDFTPAELNSLLQLAAKLKADKKSGKEE...AKLTGKNIALIFEKDSTRTRCSFEVAAYDQGARVTYLGPSGSQIGHKESIKDTARVLGRMYDGIQYRGYGQEIVETLAEYASVPVWNGLTNEFHPTQLLADLLTMQEHLPGKAFNEMTLVYAGD...FAQTELEEYAHYAGIPVINALTDHEHPCQVVADLLTIRENFG--RLAGLKLAYVGDG-NNVAHSLLLGCAKVGMSIAVATPEGFTPDPAVSARASEIAGRTGAEVQIL...hain> 3GD5 B 3GD5B...ndel> 1 3GD5 B 3GD

  14. Data of evolutionary structure change: 1CERQ-1GD1O [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1CERQ-1GD1O 1CER 1GD1 Q O -MKVGINGFGRIGRQVFRILHSRG-VEVALINDLTDNKT...> VAL CA 439 ALA CA 385 LEU CA 456 1GD...1 O 1GD1O VAL CA 371 LYS CA 388 VAL CA 474 1GD...1 O 1GD1O TMVIDGKMVKV

  15. Data of evolutionary structure change: 1CERD-2GD1R [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1CERD-2GD1R 1CER 2GD1 D R -MKVGINGFGRIGRQVFRILHSRG-VEVALINDLTDNKT...line>VAL CA 435 ALA CA 392 LEU CA 460 2GD...1 R 2GD1R VAL CA 367 LYS CA 379 VAL CA 462 2GD...1 R 2GD1R TMVIDGKMVK

  16. Comparison of Gd-Bz-TTDA, Gd-EOB-DTPA, and Gd-BOPTA for dynamic MR imaging of the liver in rat models.

    Science.gov (United States)

    Jaw, Twei-Shiun; Chen, Shih-Hsien; Wang, Yun-Ming; Hsu, Jui-Sheng; Kuo, Yu-Ting; Chiu, Yen-Yu; Tsai, Kun-Bow; Hsieh, Tsyh-Jyi; Liu, Gin-Chung

    2012-03-01

    To evaluate the competitive potential of a new lipophilic paramagnetic complex, Gd-Bz-TTDA [4-benzyl-3,6,10-tri (carboxymethyl)-3,6,10-triazado-decanedioic acid] compared with two other commercially available MR hepatobiliary contrast agents, gadobenate dimeglumine (Gd-BOPTA) and gadoxetic acid (Gd-EOB-DTPA), dynamic MR imaging studies were performed on normal and hepatocellular carcinoma (HCC) rat models using a 1.5-Tesla MR scanner. The results indicate that normal rats that were injected with 0.1 mmol/kg Gd-Bz-TTDA showed significantly more intense and persistent liver enhancement than those that were injected with the same dose of Gd-EOB-DTPA or Gd-BOPTA. All of these agents showed similar enhancement patterns in the implanted HCC. The liver-lesion contrast-to-noise ratios were higher and more persistent in rats that were injected with Gd-Bz-TTDA. These results indicate that Gd-Bz-TTDA is comparable with the commercially available hepatobiliary agents, Gd-EOB-DTPA and Gd-BOPTA, and can result in more intense and prolonged liver enhancement while still providing better liver-lesion discrimination. These results warrant further large-scale studies.

  17. Theoretical Magnon Dispersion Curves for Gd

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker; Harmon, B. N.; Freeman, A. J.

    1975-01-01

    The magnon dispersion curve of Gd metal has been determined from first principles by use of augmented-plane-wave energy bands and wave functions. The exchange matrix elements I(k⃗, k⃗′) between the 4f electrons and the conduction electrons from the first six energy bands were calculated under...

  18. Luminescence studies on Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses for WLED applications

    Science.gov (United States)

    Vijayakumar, M.; Uma, V.; Arunkumar, S.; Marimuthu, K.

    2015-06-01

    Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses have been prepared and optically characterized using absorption, luminescence and decay measurements. The Nephelauxetic ratios (β), Bonding parameters (δ) and Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4 and 6) were calculated to study the nature of the environment around the RE3+ ions in the prepared glasses. The yellow to blue (Y/B) intensity ratio and the chromaticity color coordinates were calculated from the luminescence measurements. The lifetimes of the 4F9/2 excited level were measured using decay curves and is found to decrease in the Dy3+:Eu3+ co-doped glass due to the occurrence of resonant energy transfer between Dy3+-Eu3+ ions and the non-exponential decay rates have been fitted with Inokuti-Hirayama (IH) model. The decay curves are well fitted for S= 6 suggesting that the interaction between active ions for the energy transfer is of dipole-dipole nature.

  19. High spin levels in /sup 151/Ho

    Energy Technology Data Exchange (ETDEWEB)

    Gizon, J.; Gizon, A.; Andre, S.; Genevey, J.; Jastrzebski, J.; Kossakowski, R.; Moszynski, M.; Preibisz, Z.

    1981-07-01

    We report here on the first study of the level structure of /sup 151/Ho. High spin levels in /sup 151/Ho have been populated in the /sup 141/Pr + /sup 16/O and /sup 144/Sm + /sup 12/C reactions. The level structure has been established up to 6,6 MeV energy and the spins and parities determined up to 49/2/sup -/. Most of the proposed level configurations can be explained by the coupling of h sub(11/2) protons to fsub(7/2) and/or hsub(9/2) neutrons. An isomer with 14 +- 3 ns half-life and a delayed gamma multiplicity equal to 17 +- 2 has been found. Its spin is larger than 57/2 h units.

  20. High spin levels in /sup 151/Ho

    Energy Technology Data Exchange (ETDEWEB)

    Gizon, J.; Gizon, A.; Andre, S.; Genevey, J.; Jastrzebski, J.; Kossakowski, R.; Moszynski, M.; Preibisz, Z.

    1981-07-01

    We report here on the first study of the level structure of /sup 151/Ho. High spin levels in /sup 151/Ho have been populated in the /sup 141/Pr + /sup 16/O and /sup 144/Sm + /sup 12/C reactions. The level structure has been established up to 6.6 MeV energy and the spins and parities determined up to 49/2/sup -/. Most of the proposed level configurations can be explained by the coupling of hsub(11/2) protons to fsub(7/2) and/or hsub(9/2) neutrons. An isomer with 14 +- 3 ns half-life and a delayed gamma multiplicity equal 17 +- 2 has been found. Its spin is larger than 57/2 h units.

  1. Magneto-elastic coupling across the first-order transition in the distorted kagome lattice antiferromagnet Dy3Ru4Al12

    Science.gov (United States)

    Henriques, M. S.; Gorbunov, D. I.; Kriegner, D.; Vališka, M.; Andreev, A. V.; Matěj, Z.

    2016-02-01

    Structural changes through the first-order paramagnetic-antiferromagnetic phase transition of Dy3Ru4Al12 at 7 K have been studied by means of X-ray diffraction and thermal expansion measurements. The compound crystallizes in a hexagonal crystal structure of Gd3Ru4Al12 type (P63/mmc space group), and no structural phase transition has been found in the temperature interval between 2.5 and 300 K. Nevertheless, due to the spin-lattice coupling the crystal volume undergoes a small orthorhombic distortion of the order of 2×10-5 as the compound enters the antiferromagnetic state. We propose that the first-order phase transition is not driven by the structural changes but rather by the exchange interactions present in the system.

  2. Vzduchotechnika sportovního centra

    OpenAIRE

    Šafář, Robert

    2013-01-01

    Bakalářská práce je zaměřena na návrh vzduchotechnického zařízení pro prostor tělocvičny tak, aby splňovalo funkční, hygienické a provozní požadavky na mikroklima sportovních objektů. Hlavními úkoly zařízení jsou pokrytí tepelných ztrát prostoru tělocvičny v zimním období a doprava čerstvého vzduchu do místnosti. Systém je navržen také pro pokrytí letních tepelných zisků. První teoretická část se zabývá způsoby zpětného získávání tepla pro potřeby klimatizace a druhá část obsahuje návrh dvou ...

  3. The Ras antagonist, farnesylthiosalicylic acid (FTS, decreases fibrosis and improves muscle strength in dy/dy mouse model of muscular dystrophy.

    Directory of Open Access Journals (Sweden)

    Yoram Nevo

    Full Text Available The Ras superfamily of guanosine-triphosphate (GTP-binding proteins regulates a diverse spectrum of intracellular processes involved in inflammation and fibrosis. Farnesythiosalicylic acid (FTS is a unique and potent Ras inhibitor which decreased inflammation and fibrosis in experimentally induced liver cirrhosis and ameliorated inflammatory processes in systemic lupus erythematosus, neuritis and nephritis animal models. FTS effect on Ras expression and activity, muscle strength and fibrosis was evaluated in the dy(2J/dy(2J mouse model of merosin deficient congenital muscular dystrophy. The dy(2J/dy(2J mice had significantly increased RAS expression and activity compared with the wild type mice. FTS treatment significantly decreased RAS expression and activity. In addition, phosphorylation of ERK, a Ras downstream protein, was significantly decreased following FTS treatment in the dy(2J/dy(2J mice. Clinically, FTS treated mice showed significant improvement in hind limb muscle strength measured by electronic grip strength meter. Significant reduction of fibrosis was demonstrated in the treated group by quantitative Sirius Red staining and lower muscle collagen content. FTS effect was associated with significantly inhibition of both MMP-2 and MMP-9 activities. We conclude that active RAS inhibition by FTS was associated with attenuated fibrosis and improved muscle strength in the dy(2J/dy(2J mouse model of congenital muscular dystrophy.

  4. Low Noise, tunable Ho:fiber Soliton Oscillator for Ho:YLF Amplifier Seeding

    CERN Document Server

    Li, Peng; Bransley, Colleen; Hartl, Ingmar

    2015-01-01

    We present a passively mode-locked, tunable soliton Ho:fiber ring oscillator, optimized for seeding of Ho:YLF amplifiers. The oscillator is independently tunable in central wavelength and spectral width from 2040 nm to 2070 nm and from 5 nm to 10 nm, respectively. At all settings the pulse energy within the soliton is around 800 pJ. The soliton oscillator was optimized to fully meets the spectral requirements for seeding Ho:YLF amplifiers. Its Kelly sidebands are located outside the amplifier gain spectrum, resulting in a train of about 1 ps long pedestal-free pulses with relative intensity noise (RIN) of only 0.13 % RMS when integrated from 1 Hz to Nyquist frequency.

  5. Low noise, tunable Ho:fiber soliton oscillator for Ho:YLF amplifier seeding

    Science.gov (United States)

    Li, Peng; Ruehl, Axel; Bransley, Colleen; Hartl, Ingmar

    2016-06-01

    We present a passively mode-locked, tunable soliton Ho:fiber ring oscillator, optimized for seeding of holmium-doped yttrium lithium flouride (Ho:YLF) amplifiers. The oscillator is independently tunable in central wavelength and spectral width from 2040 to 2070 nm and from 5 to 10 nm, respectively. At all settings the pulse energy within the soliton is around 800 pJ. The soliton oscillator was optimized to fully meet the spectral requirements for seeding Ho:YLF amplifiers. Its Kelly sidebands are located outside the amplifier gain spectrum, resulting in a train of about 1 ps long pedestal-free pulses with relative intensity noise of only 0.13% RMS when integrated from 1 Hz to Nyquist frequency.

  6. Electro-mechanical character of Gd and Gd{sub 2}In and possibility of a Kondo-like behavior in Gd{sub 2}In

    Energy Technology Data Exchange (ETDEWEB)

    Sarvestani, N. Kamali, E-mail: n_kamali@std.du.ac.ir [School of Physics, Damghan University, P.O. Box 36716-41167, Damghan (Iran, Islamic Republic of); Ketabi, S. Ahmad [School of Physics, Damghan University, P.O. Box 36716-41167, Damghan (Iran, Islamic Republic of); Yazdani, A. [Department of Physics, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of)

    2014-11-15

    Highlights: • The elastic constants of Gd and Gd{sub 2}In using DFT with PBE/PBE+U were calculated. • We found out the relationship between Bulk and Shear moduli with c.e.c. • We found the possibility of Kondo-like behavior in Gd{sub 2}In through the Poison’s ratio. • Through DOS, we found the possibility of c.e.c around the magnetic ions in Gd{sub 2}In. • We found out the reduction of magnetic moment due to the induced spin polarization. - Abstract: The elastic constants of Gd-element and Gd{sub 2}In have been determined by density functional theory (DFT). Mechanical properties have been specified and compared with available experimental results. In this work, a detailed ab initio study on Gd and Gd{sub 2}In are presented in order to investigate the magneto-elastic and electronic properties and to consider the tune parameters involved in these values. The relationship between these data and the possibility of Kondo-like effect in Gd{sub 2}In were discussed.

  7. Lanthanide complexes of tritopic bis(hydrazone) ligands: single-molecule magnet behavior in a linear Dy(III)3 complex.

    Science.gov (United States)

    Anwar, Muhammad U; Tandon, Santokh S; Dawe, Louise N; Habib, Fatemah; Murugesu, Muralee; Thompson, Laurence K

    2012-01-16

    Tritopic pyridinebis(hydrazone)-based ligands typically produce square M(9) [3 × 3] grid complexes with first-row transition-metal ions (e.g., M = Mn, Fe, Co, Cu, Zn), but with larger lanthanide ions, such coordination motifs are not produced, and instead linear trinuclear complexes appear to be a preferred option. The reaction of 2pomp [derived from pyridine-2,6-bis(hydrazone) and 2-acetylpyridine] with La(III), Gd(III), and Dy(III) salts produces helical linear trinuclear [Ln(3)(2pomp)(2)]-based complexes, where each metal ion occupies one of the three tridentate ligand pockets. Two ligands encompass the three metal ions, and internal connections between metal ions occur through μ-O(hydrazone) bridges. Coligands include benzoate, nitrate, and N,N-dimethylformamide. The linear Dy(III)(3) complex exhibits single-molecule magnet behavior, demonstrated through alternating-current susceptibility measurements. Slow thermal magnetic relaxation was detected in an external field of 1800 Oe, where quantum-tunneling effects were suppressed (U(eff) = 14 K).

  8. Crystal and magnetic structure of the R{sub 15}Si{sub 9}C compounds (R = Ho, Er, Tb)

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, C [Institut Laue-Langevin, BP 156, F-38042 Grenoble (France); Wrubl, F; Pani, M; Manfrinetti, P [Dipartimento di Chimica e Chimica Industriale, Universita di Genova, Via Dodecaneso 31, I-16146 Genova (Italy); Hill, A H, E-mail: ritter@ill.fr, E-mail: chimfis@chimica.unige.it [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex (France)

    2011-07-27

    The synthesis of the new compounds R{sub 15}Si{sub 9}C with R = Sm, Gd-Er, Y and R{sub 15}Ge{sub 9}C with R = Ce, Pr and Nd has been recently reported; these compounds crystallize in the hexagonal La{sub 15}Ge{sub 9}Fe structure type, hP50-P6{sub 3}mc, Z = 2 (ordered superstructure of La{sub 5}Ge{sub 3} (Mn{sub 5}Si{sub 3}-type, hP 16-P6{sub 3}/mcm, Z = 2)). Here we report the results of a neutron diffraction investigation that we have performed to study the crystal and magnetic structures of the R{sub 15}Si{sub 9}C compounds with R = Tb, Ho and Er. All three compounds see the establishment of commensurate magnetic order with a predominantly ferromagnetic interaction. Details of mixed antiferro-ferromagnetic spin arrangements ({kappa} = [000]) (for Tb{sub 15}Si{sub 9}C and Ho{sub 15}Si{sub 9}C) or of purely ferromagnetic ordering (Er{sub 15}Si{sub 9}C), and of their temperature dependence, are given and linked to the different coordination of the four dissimilar rare earth sites. In the Tb and Ho compounds the thermal evolution of the magnetic moment values strongly differs between the different R sites. The position occupied by the principal carbon has been determined (Wyckoff site 2b) and the existence of a second position available for the interstitial carbon (Wyckoff site 2a) has been revealed for R = Ho, Tb. Moreover, in the Tb and Ho compounds the magnetic moment value of the rare earth site R4, surrounding the second interstitial carbon site, is strongly reduced if compared to the value on the other rare earth sites. The magnetic transition temperatures of all three compounds, i.e. T{sub C} = 130, 43 and 45 K for Tb{sub 15}Si{sub 9}C, Ho{sub 15}Si{sub 9}C and Er{sub 15}Si{sub 9}C, are remarkably high compared to those of the parent R{sub 5}Si{sub 3} compounds. The magnetic behaviour of the partly filled Tb{sub 5}Si{sub 3}C{sub 0.25} is reported.

  9. Thermal and nuclear hyperfine properties of Ho(OH)3

    Science.gov (United States)

    Karmakar, S.

    1985-05-01

    A reasonable explanation for the findings of Catanese and Meissner [Phys. Rev. B 8, 2071 (1973)] regarding the (hyperfine) heat capacity in the low-temperature region of Ho(OH)3 is given. The Schottky specific heat in the high-temperature region observed calorimetrically by Chirico et al. [J. Chem. Thermodyn. 13, 1092 (1981)] explained satisfactorily. Nuclear hyperfine constants for Ho3+ ions in Ho(OH)3 are determined.

  10. Anion-templated assembly and magnetocaloric properties of a nanoscale {Gd38} cage versus a {Gd48} barrel.

    Science.gov (United States)

    Guo, Fu-Sheng; Chen, Yan-Cong; Mao, Ling-Ling; Lin, Wei-Quan; Leng, Ji-Dong; Tarasenko, Róbert; Orendáč, Martin; Prokleška, Jan; Sechovský, Vladimír; Tong, Ming-Liang

    2013-10-25

    The comprehensive study reported herein provides compelling evidence that anion templates are the main driving force in the formation of two novel nanoscale lanthanide hydroxide clusters, {Gd38(ClO4)6} (1) and {Gd48Cl2(NO3)} (2), characterized by single-crystal X-ray crystallography, infrared spectroscopy, and magnetic measurements. {Gd38(ClO4)6}, encapsulating six ClO4(-) ions, features a cage core composed of twelve vertex-sharing {Gd4} tetrahedrons and one Gd⋅⋅⋅Gd pillar. When Cl(-) and NO3(-) were incorporated in the reaction instead of ClO4(-), {Gd48Cl2(NO3)} is obtained with a barrel shape constituted by twelve vertex-sharing {Gd4} tetrahedrons and six {Gd5} pyramids. What is more, the cage-like {Gd38} can be dynamically converted into the barrel-shaped {Gd48} upon Cl(-) and NO3(-) stimulus. To our knowledge, it is the first time that the linear M-O-M' fashion and the unique μ8-ClO4(-) mode have been crystallized in pure lanthanide complex, and complex 2 represents the largest gadolinium cluster. Both of the complexes display large magnetocaloric effect in units of J kg(-1) K(-1) and mJ cm(-3) K(-1) on account of the weak antiferromagnetic exchange, the high N(Gd)/M(W) ratio (magnetic density), and the relatively compact crystal lattice (mass density).

  11. The Photoluminescence Properties of Dendritic Phosphors Ca₂Gd₈(SiO₄)₆O₂:A (A = Eu³⁺ and Dy³⁺) for White-Light-Emitting Diodes.

    Science.gov (United States)

    Xiumei, Han; Xin, Yan; Jianquan, Qi; Xiwei, Qi; Xiaoqiang, Wang; Mingya, Li; Xudong, Sun; Chen, Wei

    2016-01-01

    Ca₂Gd₈(SiO₄)₆O₂:A (A = Eu³⁺ and Dy³⁺) phosphors were successfully synthesized by the sol-gel process. X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicated that the diffraction peaks of the phosphor powder agreed well with the standard card. Under short ultraviolet excitation, the doped rare earth ions (A) showed their characteristic emis- sions in Ca⁺Gd₈(SiO₄)₆O₂ phophors, i.e., ⁵D₀ --> ⁷F₂ (615 nm) for Eu³⁺ and ⁴F₉/₂2 --> ⁶H₁₅/₂ (483 nm) and ⁴F₉/₂ --> ⁶H₁₃/₂ (575 nm) for Dy³⁺. The optimum concentration for doped rare earth ions was determined to be 9 mol% Eu³⁺ and 3 mol% Dy³⁺ of Gd³⁺ in Ca₂Gd₈(SiO₄)₆O₂

  12. A Comparative Study of the Electronic and Magnetic Properties of Gd5Ge4 and Gd5Si4 Compounds

    Science.gov (United States)

    Z. Momeni, Larimi; Amirabadizadeh, A.; Yazdani, A.; Arabi, H.

    2014-12-01

    We present a comparative study of electronic structure and magnetic properties of Gd5Si4 and Gd5Ge4 compounds using first principles full potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT) using the WIEN2k code. The local-spin density approximation with correlation energy (LSDA+U) method has been used as the exchange-correlation potential. The optimized lattice constants are in good agreement with the experimental data. The total and partial density of states (DOS) of Gd5Si4 and Gd5Ge4 show the difference in Si 3p-Gd 5d and Ge 4p-Gd 5d hybridization, which have an effective role in indirect exchange interaction. In addition, the magnetic moments of Gd, Si, and Ge atoms and the compounds are calculated to clarify the differences in the magnetic properties of these compounds.

  13. Pressure Induced Structural Transformation in Gd2Ti2O7 and Gd2Zr2O7

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Haiyan Y.; Weber, William J.

    2011-01-05

    Ab initio total energy calculations have been performed to study the phase stability of Gd2Ti2O7 and Gd2Zr2O7 pyrochlores over the pressure range from 0 to 60 GPa. Both compounds are unstable under pressure, and phase transformations to the defect-cotunnite structure are predicted. The phase transformation pressure of 43.6 GPa for Gd2Ti2O7 is considerably larger than the value of 13 GPa for Gd2Zr2O7, in good agreement with experiments. The decreased structural stability of Gd2Zr2O7 under pressure, relative to Gd2Ti2O7, is a consequence of the lower compressibility of the langZr–Orang bond and the higher compressibility of the langGd–Orang bond. In addition, the Gd 4f electrons are found to have only a small effect in determining the pressure induced phase transformation.

  14. Electron Capture in 163Ho and Overlap plus Exchange Corrections and the Neutrino Mass

    CERN Document Server

    Faessler, Amand; Simkovic, M F

    2014-01-01

    Holmium offers perhaps the best chance to determine the neutrino mass by electron capture. This contribution treats the electron capture in 163Holmium completely relativistic for the overlap and exchange corrections. The theoretical expressions are derived consistently in second quantisation with the help of Wick's theorem assuming single Slater determinants for the initial Ho and the final Dy atoms with holes in the final ns1/2 and np1/2 states. No hand waving arguments are needed to derive the exchange terms. It seems, that for the first time the multiplicity of electrons in the orbital overlaps are included in the numerical treatment. Electron capture e + p --> n + neutrino is proportional to the probability to find the captured electron in the parent atom at the nucleus. Non-relativistically this is only possible for ns1/2 electron states. Relativistically also p1/2 electrons have a probability to be at the nucleus due to the lower part of the relativistic electron spinor, which does not disappear at the ...

  15. Study on Micro Electrolysis Treatment for Decolorizing Dyed Water

    Institute of Scientific and Technical Information of China (English)

    王敏欣; 朱书全; 何绪文

    2001-01-01

    Method for decolrizing dyed wastewater was researched and the affecting factors dicussed. The result shows that the conditions for getting an optimum decolorization effect are: a reaction time of 60 min, a coke size of 5~10 mm, a solid/liquid ratio of 1∶10, an air blast volume of 4 m3/h, and proper Fe/coke ratio determined by the type of dye material. The system acidity influences dyed wastewater in different ways, i.e., acid condition is good for the decolorization of scarlet 3R and methyl orange simulated wastewater but bad for that of alkali violet 5BN simulated wastewater, while the decolorization of dispersed yellow E-RGFL simulated wastewater has nothing to do with pH.

  16. Hyperfine Structure and Isotope Shifts in Dy II

    Directory of Open Access Journals (Sweden)

    Dylan F. Del Papa

    2017-01-01

    Full Text Available Using fast-ion-beam laser-fluorescence spectroscopy (FIBLAS, we have measured the hyperfine structure (hfs of 14 levels and an additional four transitions in Dy II and the isotope shifts (IS of 12 transitions in the wavelength range of 422–460 nm. These are the first precision measurements of this kind in Dy II. Along with hfs and IS, new undocumented transitions were discovered within 3 GHz of the targeted transitions. These atomic data are essential for astrophysical studies of chemical abundances, allowing correction for saturation and the effects of blended lines. Lanthanide abundances are important in diffusion modeling of stellar interiors, and in the mechanisms and history of nucleosynthesis in the universe. Hfs and IS also play an important role in the classification of energy levels, and provide a benchmark for theoretical atomic structure calculations.

  17. Magnetoelectricity of single molecular toroics: The Dy4 ring cluster

    Science.gov (United States)

    Popov, A. I.; Plokhov, D. I.; Zvezdin, A. K.

    2016-11-01

    Spin-electric interactions and magnetic and magnetoelectric properties of the Dy4 ring molecular nanocluster are investigated. The effective spin-electric Hamiltonian is derived on a base of developed quantum mechanical model of the cluster spin structure. It is shown that the toroidal moment is a source of the quantum magnetoelectric effect. The dynamics of the toroidal moment (macroscopic quantum tunneling) is also discussed.

  18. EST Table: DY230642 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available DY230642 EST01377 10/09/28 42 %/114 aa ref|YP_015696.1| polyprotein [Kakugo virus] ...dbj|BAD06930.1| polyprotein [Kakugo virus] 10/09/03 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h DN237490 BmP ...

  19. PENGENDALIAN DALAM PENERBITAN IZIN GANGGUAN (HO

    Directory of Open Access Journals (Sweden)

    Pebriana Marlinda

    2017-04-01

    Full Text Available Abstrak :            Penelitian tentang pengendalian dalam penerbitan izin gangguan (HO di Kecamatan Margahayu Kabupaten Bandung menjelaskan tentang tahap-tahap pengendalian yang dilakukan oleh aparat Kecamatan Margahayu. Pengendalian dilakukan untuk memastikan agar penerbitan izin gangguan (HO berjalan dengan efektif. Namun, masih ada pelaku usaha yang belum memiliki surat izin gangguan (HO ataupun pelaku usaha yang sudah memiliki surat izin gangguan (HO akan tetapi kegiatan usahanya merugkan orang lain seperti sampah yang berserakan, polusi udara, polusi suara, dan lain-lain.                            Metode penelitian yang digunakan adalah metode penelitian deduktif kualitatif dengan teknik pengumpulan data melalui studi kepustakaan dan studi lapangan yang meliputi observasi dan wawancara mendalam. Adapun penentuan informan dalam penelitian ini dipilih berdasarkan pertimbangan-pertimbangan dengan pihak-pihak yang terkait dalam pengendalian. Kemudian data yang diperoleh dari hasil wawancara dipaparkan dengan langkah-langkah yang meliputi: reduksi data, penyajian data, menarik kesimpulan/verifikasi. Teori yang digunakan penulis dalam penelitian ini adalah teori dari Stephen P. Robbins tentang tahap-tahap pengendalian yaitu: mengukur kinerja aktual, membandingkan kinerja aktual dengan standar, dan mengambil tindakan manajerial.                            Kesimpulan dari hasil penelitian ini adalah pengendalian yang dilakukan olehaparat Kecamatan Margahayu telah melalui tahap-tahap pengendalian yaitu: mengukur kinerja aktual, membandingkan kinerja aktual dengan standar, dan mengambil tindakan manajerial. Namun perlu dilakukan penguatan di setiap tahap pengendalian terutama pada tahap mengukur kinerja aktual dan pada tahap mengambil tindakan manajerial                            Penelitian tentang pengendalian dalam penerbitan izin gangguan (HO di Kecamatan

  20. Gd-substituted Bi-2223 superconductor

    Indian Academy of Sciences (India)

    D R Mishra

    2008-03-01

    The effects of gadolinium doping at calcium site on the normal and super-conducting properties of Bi-2223 system were studied. The Gd-doped (BiPb)-2223 series of specimens, namely Batch I, II and III were sintered at three different sintering temperatures 830, 850 and 895° C respectively. The properties investigated are (1) the normal state resistivity with a view to study metal-to-insulator transition, (2) the XRD patterns of the specimens with a view to study the relative composition of (BiPb)-2212 and (BiPb)-2223 phases and (3) the superconducting fluctuation behaviour (SFB) with a view to determine the effect of doping, if any, on the dimensionality of the fluctuation conductivity of the system. The normal state resistivity of Gd-substituted Bi-2223 specimens shows metallic, semiconducting and insulating behaviour. The c( = 0) values indicate that (BiPb)-2223 phase is responsible for the observed superconducting transitions in Batch I and Batch II specimens with Gd concentrations ≤ 0.7. This observation is further confirmed in the analysis of XRD patterns of these specimens. Gadolinium, being a magnetic impurity, has pair breaking effect near the Fermi level and decreases c( = 0). The analysis of the superconducting fluctuation behaviour (SFB) shows a 2D dimensionality without any cross-over.

  1. The Radio Evolution of SN 2001gd

    CERN Document Server

    Stockdale, Christopher J; Weiler, Kurt W; Panagia, Nino; Sramek, Richard A; Van Dyk, Schuyler D; Kelley, Matthew T

    2007-01-01

    We present the results of observations of the radio emission from Supernova 2001gd in NGC 5033 from 2002 February 8 through 2006 September 25. The data were obtained using the Very Large Array at wavelengths of 1.3 cm (22.4 GHz), 2 cm (14.9 GHz), 3.6 cm (8.4 GHz), 6 cm (4.9 GHz), and 20 cm (1.5 GHz), with one upper limit at 90 cm (0.3 GHz). In addition, one detection has been provided by the Giant Metrewave Radio Telescope at 21 cm (1.4 GHz). SN 2001gd was discovered in the optical well past maximum light, so that it was not possible to obtain many of the early radio "turn-on" measurements which are important for estimating the local circumstellar medium (CSM) properties. Only at 20 cm were turn-on data available. However, our analysis and fitting of the radio light curves, and the assumption that the Type IIb SN 2001gd resembles the much better studied Type IIb SN 1993J, enables us to describe the radio evolution as being very regular through day ~550 and consistent with a nonthermal-emitting model with a th...

  2. Study on the thermoluminescent properties of K{sub 2}YF{sub 5} and K{sub 2}GdF{sub 5} crystals doped with optically active trivalent ions for gamma and neutrons dosimetry; Estudo das propriedades termoluminescentes de cristais de K{sub 2}YF{sub 5} e K{sub 2}GdF{sub 5} dopados com ions trivalentes opticamente ativos para dosimetria gama e de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edna Carla da

    2008-07-01

    In this work, the thermoluminescent (TL) properties of both double potassium yttrium fluoride (K{sub 2}YF{sub 5}) and double potassium gadolinium fluoride (K{sub 2}GdF{sub 5}) crystals doped with optically active rare earth ions were investigated from the point of view of gamma and neutron dosimetry. Crystalline platelets with thickness of about 1 mm, synthesized under hydrothermal conditions, were irradiated in order to study TL sensitivity, as well as dose and energy response, reproducibility and fading, in terms of Ce{sup 3+}, Tb{sup 3+}, Dy{sup 3+}, e Pr{sup 3+} concentrations. The K{sub 2}YF{sub 5} crystals doped with 1.0 at por cent Dy{sup 3+} have been found to have an excellent linear TL response to X and gamma photons, in the range of 0.01 to 10 mGy. The TL output is comparable to that of CaS0{sub 4}:Mn dosemeters. The main peak at 130 deg C has been found to have a TL response for 41.1 keV X-ray energy 32 times higher than that for 662 keV gamma rays. This fact points out that the K{sub 2}Y{sub 0.99}Dy{sub 0.01}F{sub 5} crystals have great potential for X-rays diagnostic and/or industrial radiography. On the other hand, the K{sub 2}GdF{sub 5} crystals doped with 5.0 at por cent Dy{sup 3+} have been found to have the better TL response for gamma and fast neutron radiation, among the dopants studied. For gamma fields the TL response was linear for doses ranging from 0.1 to 200 mGy. The TL peak around 200 deg C can be deconvoluted into four individual peaks, all of them with linear behavior. For fast neutron radiation produced by an {sup 241}Am{sub B}e source, the TL responses for doses ranging from 0.6 to 12 mSv were also linear and comparable to that of commercial TLD-600, irradiated at same conditions. The TL emission due to neutrons was in the high temperature range, above 200 deg C. These results points out that K{sub 2}Gd{sub 0.95}Dy{sub 0.05}F{sub 5} crystals are good candidates for use in neutron dosimetry applications. (author)

  3. Influence of Warp Yarn Tension on Cotton Greige and Dyed Woven Fabric Prosperities

    OpenAIRE

    Uzma Syed; Rafique Ahmed Jhatial

    2013-01-01

    Fabric properties such as pilling and abrasion resistance and tensile strength vary when greige fabric is processed further. The quality of dyed fabric depends on the quality of greige fabric. Cotton Plain and Twill weave fabrics were woven at three different warp yarn tension and then dyed using monochlorotriazine, Drimerene Red Cl-5B dye gives difference in fabric properties. The ASTM, American International Standards were used to determine the greige and dyed fabric properties. It has been...

  4. Effect of Ligand Substitution around the Dy(III) on the SMM Properties of Dual-Luminescent Zn-Dy and Zn-Dy-Zn Complexes with Large Anisotropy Energy Barriers: A Combined Theoretical and Experimental Magnetostructural Study.

    Science.gov (United States)

    Costes, Jean Pierre; Titos-Padilla, Silvia; Oyarzabal, Itziar; Gupta, Tulika; Duhayon, Carine; Rajaraman, Gopalan; Colacio, Enrique

    2016-05-02

    The new dinuclear Zn(II)-Dy(III) and trinuclear Zn(II)-Dy(III)-Zn(II) complexes of formula [(LZnBrDy(ovan) (NO3)(H2O)](H2O)·0.5(MeOH) (1) and [(L(1)ZnBr)2Dy(MeOH)2](ClO4) (3) (L and L(1) are the dideprotonated forms of the N,N'-2,2-dimethylpropylenedi(3-methoxysalicylideneiminato and 2-{(E)-[(3-{[(2E,3E)-3-(hydroxyimino)butan-2-ylidene ]amino}-2,2-dimethylpropyl)imino]methyl}-6-methoxyphenol Schiff base compartmental ligands, respectively) have been prepared and magnetostructurally characterized. The X-ray structure of 1 indicates that the Dy(III) ion exhibits a DyO9 coordination sphere, which is made from four O atoms coming from the compartmental ligand (two methoxy terminal groups and two phenoxido bridging groups connecting Zn(II) and Dy(III) ions), other four atoms belonging to the chelating nitrato and ovanillin ligands, and the last one coming to the coordinated water molecule. The structure of 3 shows the central Dy(III) ion surrounded by two L(1)Zn units, so that the Dy(III) and Zn(II) ions are linked by phenoxido/oximato bridging groups. The Dy ion is eight-coordinated by the six O atoms afforded by two L(1) ligands and two O atoms coming from two methanol molecules. Alternating current (AC) dynamic magnetic measurements of 1, 3, and the previously reported dinuclear [LZnClDy(thd)2] (2) complex (where thd = 2,2,6,6-tetramethyl-3,5-heptanedionato ligand) indicate single molecule magnet (SMM) behavior for all these complexes with large thermal energy barriers for the reversal of the magnetization and butterfly-shaped hysteresis loops at 2 K. Ab initio calculations on 1-3 show a pure Ising ground state for all of them, which induces almost completely suppressed quantum tunnelling magnetization (QTM), and thermally assisted quantum tunnelling magnetization (TA-QTM) relaxations via the first excited Kramers doublet, leading to large energy barriers, thus supporting the observation of SMM behavior. The comparison between the experimental and theoretical

  5. Observations of OH and HO2 radicals over West Africa

    Directory of Open Access Journals (Sweden)

    D. E. Heard

    2010-03-01

    Full Text Available The hydroxyl radical (OH plays a key role in the oxidation of trace gases in the troposphere. However, observations of OH and the closely related hydroperoxy radical (HO2 have been sparse, especially in the tropics. Based on a low-pressure laser-induced fluorescence technique (FAGE – Fluorescence Assay by Gas Expansion, an instrument has been developed to measure OH and HO2 aboard the Facility for Airborne Atmospheric Measurement (FAAM BAe-146 research aircraft. The instrument is described and the calibration method is discussed. During the African Monsoon Multidisciplinary Analyses (AMMA campaign, observations of OH and HO2 (HOx were made in the boundary layer and free troposphere over West Africa on 13 flights during July and August 2006. Mixing ratios of both OH and HO2 were found to be highly variable but followed a diurnal cycle, with a median HO2/OH ratio of 95. Daytime OH observations were compared with the primary production rate of OH from ozone photolysis in the presence of water vapour. Daytime HO2 observations were generally reproduced by a simple steady-state HOx calculation, where HOx was assumed to be formed from the primary production of OH and lost through HO2 self-reaction. Deviations between the observations and this simple model were found to be grouped into a number of specific cases: (a in the presence of high levels of isoprene in the boundary layer, (b within a biomass burning plume and (c within cloud. In the forested boundary layer, HO2 was underestimated at altitudes below 500 m but overestimated between 500 m and 2 km. In the biomass burning plume, OH and HO2 were both significantly reduced compared to calculations. HO2 was sampled in and around cloud, with significant short-lived reductions of HO2 observed. HO2 observations were better reproduced by a steady state calculation with heterogeneous loss of HO2 onto cloud droplets included. Up to 9 pptv of HO2 was observed at night, increasing early in the morning

  6. Magnetic properties, water proton relaxivities, and in-vivo MR images of paramagnetic nanoparticles

    Science.gov (United States)

    Lee, Gang Ho; Chang, Yongmin

    2015-07-01

    In this mini review, magnetic resonance imaging (MRI) contrast agents based on lanthanideoxide (Ln2O3) nanoparticles are described. Ln2O3 (Ln = Gd, Dy, Ho, and Er) nanoparticles are paramagnetic, but show appreciable magnetic moments at room temperature and even at ultrasmall particle diameters. Among Ln2O3 nanoparticles, Gd2O3 nanoparticles show larger longitudinal water proton relaxivity (r1) values than Gd-chelates because of the large amount of Gd in the nanoparticle, and the other Ln2O3 nanoparticles (Ln = Dy, Ho, and Er) show appreciable transverse water proton relaxivity (r2) values. Therefore, Gd2O3 nanoparticles are potential T1 MRI contrast agents while the other Ln2O3 nanoparticles are potential T2 MRI contrast agents at high MR fields.

  7. Effect of LiF on Densification and Mechanical Properties of Dy-α-Sialon Ceramics

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effect of LiF on the densification and mechanical properties of hot-pressed Dy-α-sialon ceramics was studied. Comparatively, without LiF as sintering additive, the pure Dy-α-sialon ceramic should be sintered at 1750 ℃. When LiF is used, the sintering temperature of the Dy-α-sialon is greatly lowered to 1500~1650 ℃. Obviously, the addition of LiF has a strong effect on the improvement in densification. Meanwhile, the resultant Dy-α-sialon has no significant changes in the mechanical properties.

  8. Phase relationship of Dy-Fe-Mn system at 773 K

    Institute of Scientific and Technical Information of China (English)

    杜成梅; 马君; 姚路; 陈国坚; 杨通晗; 曾维敬; 何维

    2014-01-01

    Rare-earth intermetallic compounds formed in many R-Fe-Mn (R=rare-earth element) systems exhibit excellent properties. In order to understand the existence and stability of the compounds in the system and further search for the potential application of R-Fe-Mn alloys in various aspects, it is necessary to investigate the phase relations of the Dy-Fe-Mn ternary system. A total of 96 samples of the Dy-Fe-Mn alloys were prepared by arc-melting and examined by metallographic analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques. The phase relationship of the Dy-Fe-Mn system at 773 K was determined. It was found that the isothermal section was characterized by intermediate solid solutions based on the substitutions of Fe/Mn atoms and the large extensions of the binaries into the ternary domains. The solid solubilities of the third ele-ment in the binary compounds and the phase boundaries were also determined by XRD technique using the phase disappearing method combined with the lattice parameter method and SEM/EDS technique. Two pairs of corresponding binary compounds in the Dy-Fe and Dy-Mn systems (DyFe2 and DyMn2, Dy6Fe23 and Dy6Mn23) formed a continuous series of solid solution at 773 K, respectively.

  9. Yellow persistent luminescence of Sr2SiO4:Eu2+,Dy3+

    NARCIS (Netherlands)

    Dutczak, D.A.; Milbrat, A.; Katelnikovas, A.; Meijerink, A.; Ronda, R.C.; Jüstel, T.

    2012-01-01

    This paperreportsthephotoluminescenceandafterglowofSr2SiO4 doped withEu2þ and Dy3þ. Factors governingtheformationofthemonoclinicororthorhombicphaseofthisortho-silicatearedescribed and theimpactofthecrystallographicmodificationontheluminescenceandafterglowunderUVand VUV

  10. Synthesis and Characterization of a Novel Compound SnDy2O4

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new phase, the rare earth complex oxide SnDy2O4 was synthesized by the thermal decomposition of its oxalate precursor that was prepared by rheological phase reaction method. TG, IR, XRD and EPS were used to prove the formation of the compound SnDy2O4. The structure of SnDy2O4 was refined by Rietveld analysis. SnDy2O4 is cubic, a = 7.40366A, V = 405.82A3, Z = 4.

  11. A structural and functional perspective of DyP-type peroxidase family.

    Science.gov (United States)

    Yoshida, Toru; Sugano, Yasushi

    2015-05-15

    Dye-decolorizing peroxidase from the basidiomycete Bjerkandera adusta Dec 1 (DyP) is a heme peroxidase. This name reflects its ability to degrade several anthraquinone dyes. The substrate specificity, the amino acid sequence, and the tertiary structure of DyP are different from those of the other heme peroxidase (super)families. Therefore, many proteins showing the similar amino acid sequences to that of DyP are called DyP-type peroxidase which is a new family of heme peroxidase identified in 2007. In fact, all structures of this family show a similar structure fold. However, this family includes many proteins whose amino acid sequence identity to DyP is lower than 15% and/or whose catalytic efficiency (kcat/Km) is a few orders of magnitude less than that of DyP. A protein showing an activity different from peroxidase activity (dechelatase activity) has been also reported. In addition, the precise physiological roles of DyP-type peroxidases are unknown. These facts raise a question of whether calling this family DyP-type peroxidase is suitable. Here, we review the differences and similarities of structure and function among this family and propose the reasonable new classification of DyP-type peroxidase family, that is, class P, I and V. In this contribution, we discuss the adequacy of this family name.

  12. Luminescent investigations of Li{sub 6}Lu(BO{sub 3}){sub 3}:Tb{sup 3+}, Dy{sup 3+} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Fawad, U.; Oh, Myeongjin; Park, H. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Sunghwan [Department of Radiological Science, Cheongju University, Cheongju 360-764 (Korea, Republic of); Kim, H.J., E-mail: hongjoo@knu.ac.kr [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

    2014-10-15

    Highlights: • New Li{sub 6}Lu(BO{sub 3}){sub 3}:Tb{sup 3+}, Dy{sup 3+} phosphors were fabricated by solid state reaction method. • Li{sub 6}Lu(BO{sub 3}){sub 3}:Dy{sup 3+} emissions; 481, 578, 666 and 734 nm (λ{sub ex} = 350 nm) and for. • Li{sub 6}Lu(BO{sub 3}){sub 3}:Tb{sup 3+}; 488–492, 543–551, 578–599, 614–629 and 651–688 nm (λ{sub ex} = 305 nm). • Light yield of Li{sub 6}Lu(BO{sub 3}){sub 3}:Tb{sup 3+}; 75% while for Li{sub 6}Lu(BO{sub 3}){sub 3}:Dy{sup 3+} is 19% of PDP. • The decay time measured for Li{sub 6}Lu(BO{sub 3}){sub 3}:Tb{sup 3+} phosphor was 1.38 ms. - Abstract: In our novel work we report the luminescence properties of Terbium (Tb{sup 3+}) and Dysprosium (Dy{sup 3+}) ions in Li{sub 6}Lu(BO{sub 3}){sub 3} (lithium lutetium borate) phosphors with its specific and productive use in various luminescent display systems. We have synthesized Tb{sup 3+} and Dy{sup 3+} doped Li{sub 6}Lu(BO{sub 3}){sub 3} phosphors by the solid state reaction method. Concentration based optimization of activators is attained i.e. 2 mol% for Tb{sup 3+} and 5 mol% for Dy{sup 3+}. XRD (X-ray diffraction) and FE-SEM (Field emission-scanning electron microscopy) were used to analyze the overall morphologies, crystalline structures and the grain sizes of the prepared phosphors. Moreover, the grain size of 20 μm is confirmed via Scherrer’s formula. In order to characterize the luminescence properties of the synthesized phosphors, we measured its X-ray induced luminescence, proton induced luminescence and UV induced photoluminescence. Under UV luminescence Dy{sup 3+} doped phosphor, it displayed seven obvious peaks corresponding to transitions from {sup 6}H{sub 15/2} (f{sup 9}) ground state to higher energy state of 4f{sup 9} whereas, UV-emission spectrum of Li{sub 6}Lu(BO{sub 3}){sub 3}:Tb{sup 3+} phosphor has shown five major transitions with each peak consists of several smaller lines, confirming the complicated transition ({sup 5}D{sub j} → {sup 7}F

  13. Gd$^{3+}$ - Gd$^{3+}$ distances exceeding 3 nm determined by very high frequency continuous wave electron paramagnetic resonance

    CERN Document Server

    Clayton, Jessica A; Godt, Adelheid; Goldfarb, Daniella; Han, Songi; Sherwin, Mark S

    2016-01-01

    Electron paramagnetic resonance spectroscopy in combination with site-directed spin-labeling is a very powerful tool for elucidating the structure and organization of biomolecules. Gd$^{3+}$ complexes have recently emerged as a new class of spin labels for distance determination by pulsed EPR spectroscopy at Q- and W-band. We present CW EPR measurements at 240 GHz (8.6 Tesla) on a series of Gd-rulers of the type Gd-PyMTA---spacer---Gd-PyMTA, with Gd-Gd distances ranging from 1.2 nm to 4.3 nm. CW EPR measurements of these Gd-rulers show that significant dipolar broadening of the central $|-1/2\\rangle\\rightarrow|1/2\\rangle$ transition occurs at 30 K for Gd-Gd distances up to $\\sim$ 3.4 nm with Gd-PyMTA as the spin label. This represents a significant extension for distances accessible by CW EPR, as nitroxide-based spin labels at X-band frequencies can typically only access distances up to $\\sim$ 2 nm. We show that this broadening persists at biologically relevant temperatures above 200 K, and that this method i...

  14. The irradiation effects of Gd2Hf2O7 and Gd2Ti2O7

    Science.gov (United States)

    Li, Y. H.; Wen, J.; Wang, Y. Q.; Wang, Z. G.; Tang, M.; Valdez, J. A.; Sickafus, K. E.

    2012-09-01

    In this report, we present dramatically different behavior between isostructural Gd2Hf2O7 and Gd2Ti2O7 pyrochlore using 400 keV Ne2+ irradiation under cryogenic conditions (˜77 K), in which the lattice volume of the irradiated layer of Gd2Ti2O7 increased with ion fluence up to 1 × 1015 ions/cm2, whereas, the lattice volume of the irradiated layer of Gd2Hf2O7 decreased with increasing fluence from 1 × 1015 to 6 × 1016 ions/cm2. The cation radius ratio rA/rB, the bond-type of A-O and B-O bonds, the order-to-disorder transition energy of Gd2Hf2O7 and Gd2Ti2O7, temperature-composition (T-C) phase diagrams of HfO2-Gd2O3 and TiO2-Gd2O3 mixtures were used to explain the response of Gd2Hf2O7 and Gd2Ti2O7 to ion irradiation-induced structure transformation.

  15. Magnetic phase diagram of Ho-Ag

    Energy Technology Data Exchange (ETDEWEB)

    Paul-Boncour, V [Chimie Metallurgique des Terres Rares, ICMPE, CNRS, 2 rue H Dunant, 94320 Thiais (France); Hoser, A; Stuesser, N [Hahn-Meitner Institut, Glienicker Strasse 100, 14109, Berlin (Germany); Hense, K; Gratz, E [Institute for Experimental Physics, Technical University Vienna, Wiedner Hauptstrasse 8-10, A-1040 (Austria); Rotter, M [Institut fuer Physikalische Chemie, Universitaet Wien, Waehringerstrasse 42, 1090 Wien (Austria)], E-mail: paulbon@glvt-cnrs.fr

    2008-03-12

    The magnetic phase diagram of Ho-Ag has been established using magnetoresistance, magnetostriction and neutron diffraction experiments versus applied field and temperature. Three different magnetic phases were observed: an incommensurate antiferromagnetic phase (IC) below T{sub N} = 33 K, a commensurate antiferromagnetic phase (C) above 5 T and below T{sub 1} (5-8 K) and a ferromagnetic component above 3 T. The IC phase undergoes spin reorientations around 5 T (IC') and 13 T (IC'')

  16. Dy substitution effect on the temperature dependences of magnetostriction in Pr1-x Dy x Fe1.9 alloys

    Science.gov (United States)

    Tang, Yan-Mei; Huang, Hai-Fu; Tang, Shao-Long; Du, You-Wei

    2016-11-01

    The temperature dependences of magnetostriction in Pr1-x Dy x Fe1.9 (0 ≤ x ≤ 1.0) alloys between 5 K and 300 K were investigated. An unusual decrease of magnetostriction with temperature decreasing was found in Pr-rich alloys (0 ≤ x ≤ 0.2), due to the change of the easy magnetization direction (EMD). Dy substitution reduces the magnetostriction in high-magnetic field (10 kOe ≤ H ≤ 90 kOe) at 5 K, while a small amount of Dy substitution (x = 0.05) is beneficial to increasing the magnetostriction in low-magnetic field between 10 K and 50 K. This makes the alloys a potential candidate for low temperature applications. Project supported by the National Natural Science Foundation of China (Grant No. U1232210), the Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No. 2015GXNSFBA139020), and the Enhancement of the Basic Ability of Teachers of Guangxi Zhuang Autonomous Region, China (Grant No. KY2016YB068).

  17. Computer Simulation of Gd(III) Speciation in Human Interstitial Fluid

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The speciation and distribution of Gd(III) in human interstitial fluid was studied by computer simulation. Meantime artificial neural network was applied to the estimation of log β values of complexes. The results show that the precipitate species, GdPO4 and Gd2(CO3)3, are the predominant species. Among soluble species, the free Gd(III), [Gd(HSA)] , [Gd(Ox)] and then the ternary complexes of Gd(III) with citrate are main species and [Gd3(OH)4] becomes the predominant species at the Gd(III) total concentration of 2.2×10-2mol/L.

  18. Polarization enhancement and ferroelectric switching enabled by interacting magnetic structures in DyMnO3 thin films

    KAUST Repository

    Lu, Chengliang

    2013-12-02

    The mutual controls of ferroelectricity and magnetism are stepping towards practical applications proposed for quite a few promising devices in which multiferroic thin films are involved. Although ferroelectricity stemming from specific spiral spin ordering has been reported in highly distorted bulk perovskite manganites, the existence of magnetically induced ferroelectricity in the corresponding thin films remains an unresolved issue, which unfortunately halts this step. In this work, we report magnetically induced electric polarization and its remarkable response to magnetic field (an enhancement of ?800% upon a field of 2 Tesla at 2 K) in DyMnO3 thin films grown on Nb-SrTiO3 substrates. Accompanying with the large polarization enhancement, the ferroelectric coercivity corresponding to the magnetic chirality switching field is significantly increased. A picture based on coupled multicomponent magnetic structures is proposed to understand these features. Moreover, different magnetic anisotropy related to strain-suppressed GdFeO 3-type distortion and Jahn-Teller effect is identified in the films.

  19. Effects of Dy, Sr and Die Casting on Microstructure, Mechanical and Corrosion Properties of Mg-Dy-Sr-Nd-Zr Alloys

    Science.gov (United States)

    Liu, Dexue; Yin, Xunyan; Pang, Xin; Hu, Shiwen; Ding, Yutian

    2017-08-01

    By adding 2, 6 and 10 wt.% Dy and 0.5, 1.5 and 2 wt.% Sr elements to Mg-2.4Nd-0.5Zr alloys and adopting die-casting process for biomedical Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloys, the effects of Dy and Sr elements and die-casting process on the microstructure, mechanical properties and corrosion resistance of Mg-Dy-Sr-Nd-Zr alloys were investigated. The new biomedical Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloys were designed, and the grain size of the as-cast new alloy was refined to 70 μm and distributed equably. The ultimate tensile strength increased with increasing Dy content and decreasing Sr content. The corrosion rate decreased firstly and then increased with increasing Dy content and decreased with increasing Sr content. By adjusting the content of Sr and Dy, the ultimate tensile strength of as-cast new Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloys increased to 203 MPa, elongation was 7.4%, and the corrosion rate decreased to 0.48 mm/a. The elongation rate increased to 10.2% after the new biomedical alloys were processed by die casting with an refine-grained microstructure of 18 μm, meanwhile the ultimate tensile strength decreased to 180 MPa, and the corrosion rate was 1.29 mm/a.

  20. Study on Electrodeposition of Ho-Co Alloy in Dimethylsulfoxide

    Institute of Scientific and Technical Information of China (English)

    王宇; 刘冠昆; 童叶翔

    2002-01-01

    Co-deposition of Ho with Co was studied in dimethylsulfoxide (DMSO) by cyclic voltammetry and potentiostatic deposition at room temperature. The cyclic voltammogram shows that the codeposition of Ho with Co can be attributed to induced codeposition mechanism, for the codeposition potential is more negative than the deposition potential of Co but positive than that of Ho. For the potentiostatic deposition used in Ho-Co alloys preparation, the results indicate that in the range of selected concentration the potential is the main factor determining the content of Ho in Ho-Co alloys, while the composition of Ho3+ and Co2+ in electrolyte solution has less influence. According to the analysis of X-ray diffraction, EDAX, and scanning electron microscopy, uniform, compact and amorphous films on Cu can be obtained at -1.8 V (vs.SCE) in 0.165 molL-1 Ho(NO3) -0.135 mol*L-1 CoCl2-DMSO solution.

  1. Data of evolutionary structure change: 1CRWR-2GD1R [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1CRWR-2GD1R 1CRW 2GD1 R R -SKIGINGFGRIGRLVLRAALEMG-AQVVAVNDPFIALE...DDIKAAMKAASEGPLQGVLGYTEDDVVSCDFTGDNRSSIFDAKAGIQLSKTFVKVVSWYDNEFGYSQRVIDLIKHMQKVDS...GLN CA 345 VAL CA 440 VAL CA 386 ALA CA 455 2GD1 R 2GD1R VAL CA 422 VAL CA 467 SER CA 509 2GD

  2. Data of evolutionary structure change: 1AT1A-3GD5A [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1AT1A-3GD5A 1AT1 3GD5 A A ANPLYQKHIISINDLSRDDLNLVLATAAKLKANPQPELL...KHKVIASCFFEASTRTRLSFQTSMHRLGASVVGFSDSANTSLGKKGETLADTISVISTYVDAIVMRHPQEGAARLATEFSGNVPVLNAGDGSNQHPTQTLLDLFTIQQTEGRLDNLHVAMVGD...EEYAHYAG-IPVINALTD-HEHPCQVVADLLTIRENFGRLAGLKLAYVGDGN--NVAHSLLLGCAKVG-MSIAVATPEGFTPDPAVSARASEIAGRTGAEVQIL--RD...ndex> 3GD5 A 3GD5A A... 1 3GD

  3. Partial phase diagram of Pd-Ag-Ru-Gd quaternary system

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On the basis of the Ag-Pd-Gd, Ag-Ru-Gd and Pd-Ru-Gd ternary systems, the partial phase diagram of Pd-Ag-Ru-Gd(Gd<25% atom fraction) quaternary system has been studied by means of X-ray diffraction analysis, differential thermal analysis, electron probe microanalysis and optical microscopy.The 700℃ isothermal sections of the Ag-Pd-5Ru-Gd, Ag-Pd-20Ru-Gd and Ag-Pd-50Ru-Gd (Gd≤25%atom fraction) phase diagrams were determined respectively. And the 700℃ isothermal section of the PdAg-Ru-Gd (Gd≤25% atom fraction) quaternary system phase diagram was finally irferred. The section consists of four single-phase regions: solid solution Pd(Ag), (Ru), Pd3Gd and Ag51 Gd14; five two-phase regions: Pd(Ag) + (Ru), Pd(Ag) + Ag51 Gd14 , (Ru) + Ag51 Gd14 , Pd(Ag) + Pd3Gd and (Ru) +Pd3Gd; three three-phase regions: Pd(Ag) + Pd3Gd+ (Ru), Pd(Ag) + Ag51Gd14 + (Ru) and (Ru) +Ag51Gd14 + Pd3Gd; one four-phase region Pd(Ag) + (Ru) + Ag51Gd14 + Pd3Gd. No new quaternary intermetallic phase is found.

  4. White light generation in Dy{sup 3+}-and Ce{sup 3+}/Dy{sup 3+}-doped zinc–sodium–aluminosilicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Caldiño, U., E-mail: cald@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 México, D.F. (Mexico); Lira, A. [Departamento de Física , Facultad de Ciencias, Universidad Autónoma del estado de México, C.P. 50000 Toluca (Mexico); Meza-Rocha, A.N. [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 México, D.F. (Mexico); Pasquini, E. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, Sesto Fiorentino, 50019 Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, Sesto Fiorentino, 50019 Firenze (Italy); Pelli, S. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, Sesto Fiorentino, 50019 Firenze (Italy); Speghini, A. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, Sesto Fiorentino, 50019 Firenze (Italy); Dipartimento di Biotecnologie, Università di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); Bettinelli, M. [Dipartimento di Biotecnologie, Università di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); Righini, G.C. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, Sesto Fiorentino, 50019 Firenze (Italy); Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Piazza del Viminale 2, 00184 Roma (Italy)

    2015-11-15

    A spectroscopic investigation of 1% Dy{sub 2}O{sub 3}-singly doped and 0.5% Ce{sub 2}O{sub 3}-1.0% Dy{sub 2}O{sub 3}-codoped zinc–sodium–aluminosilicate glasses was performed by analyzing their absorption and photoluminescence spectra, and decay times. Warm white yellow light emission, with (0.419, 0.440) CIE1931 chromaticity coordinates and 3579 K color temperature, is obtained in the Dy{sup 3+}-singly doped glass excited at 399 nm, which fits to the requirements of GaN LEDs. A quantum efficiency of 74% and a very high optical gain (38.7×10{sup −25} cm{sup 2} s) were estimated for the dysprosium {sup 4}F{sub 9/2} level luminescence, which might also make the Dy{sup 3+}-doped glass a promising gain medium for solid state yellow laser pumped by GaN LEDs. In the Ce{sup 3+}/Dy{sup 3+}-codoped glass a radiative energy transfer from Ce{sup 3+} to Dy{sup 3+} is observed upon UV excitation (310–365 nm), with a Ce{sup 3+} to Dy{sup 3+} interaction distance that could be greater than 6–12 Å. The emission color from the codoped glass can be tuned with the excitation wavelength from blue light (0.247, 0.245), upon 310 nm excitation, to cold white light (0.284, 0.300), with a 9052 K color temperature, upon 365 nm excitation. - Highlights: • Zinc–sodium–aluminosilicate (ZN) glasses are optically activated with Dy{sup 3+} (ZNDy). • ZN glasses are optically activated with Ce{sup 3+}/Dy{sup 3+} (ZNCeDy). • Dy{sup 3+} is sensitized by Ce{sup 3+} through a radiative energy transfer. • ZNDy glass can generate 3579 K warm white yellow light emission. • ZNCeDy glass can generate 9052 K cold white light emission.

  5. Anomalous Hall effect in Fe/Gd bilayers

    KAUST Repository

    Xu, W. J.

    2010-04-01

    Non-monotonic dependence of anomalous Hall resistivity on temperature and magnetization, including a sign change, was observed in Fe/Gd bilayers. To understand the intriguing observations, we fabricated the Fe/Gd bilayers and single layers of Fe and Gd simultaneously. The temperature and field dependences of longitudinal resistivity, Hall resistivity and magnetization in these films have also been carefully measured. The analysis of these data reveals that these intriguing features are due to the opposite signs of Hall resistivity/or spin polarization and different Curie temperatures of Fe and Gd single-layer films. Copyright (C) EPLA, 2010

  6. Targeting O-Acetyl-GD2 Ganglioside for Cancer Immunotherapy.

    Science.gov (United States)

    Fleurence, Julien; Fougeray, Sophie; Bahri, Meriem; Cochonneau, Denis; Clémenceau, Béatrice; Paris, François; Heczey, Andras; Birklé, Stéphane

    2017-01-01

    Target selection is a key feature in cancer immunotherapy, a promising field in cancer research. In this respect, gangliosides, a broad family of structurally related glycolipids, were suggested as potential targets for cancer immunotherapy based on their higher abundance in tumors when compared with the matched normal tissues. GD2 is the first ganglioside proven to be an effective target antigen for cancer immunotherapy with the regulatory approval of dinutuximab, a chimeric anti-GD2 therapeutic antibody. Although the therapeutic efficacy of anti-GD2 monoclonal antibodies is well documented, neuropathic pain may limit its application. O-Acetyl-GD2, the O-acetylated-derivative of GD2, has recently received attention as novel antigen to target GD2-positive cancers. The present paper examines the role of O-acetyl-GD2 in tumor biology as well as the available preclinical data of anti-O-acetyl-GD2 monoclonal antibodies. A discussion on the relevance of O-acetyl-GD2 in chimeric antigen receptor T cell therapy development is also included.

  7. Gd3Fe5O12 near the compensation temperature

    DEFF Research Database (Denmark)

    Hansen, Britt Rosendahl; Kuhn, Luise Theil; Bahl, Christian Robert Haffenden;

    2010-01-01

    Applying a magnetic eld to a magnetic material will usually cause a change in the magnetic entropy of the material. If done adiabatically, the temperature of the material will change - this is the magnetocaloric eect. Gadolinium Iron Garnet (GdIG, Gd3Fe5O12) is a complex magnetic system with three...... magnetic sublattices, one Gd and two Fe. The Fe sites are strongly coupled antiferromagnetically, i.e. the magnetic moments are anti-parallel, while the Gd magnetic moment is weakly coupled antiferromagnetically to the resulting Fe moment. This results in a compensation temperature, where the total...

  8. Spectroscopic properties of Dy(3+) doped ZnO for white luminescence applications.

    Science.gov (United States)

    Amira, Guesmi; Chaker, Bouzidi; Habib, Elhouichet

    2017-04-15

    Undoped and Dy(3+) (0.25, 0.5, 0.8 and 1.5at.%) doped ZnO were elaborated by solid-state reaction method. The ZnO:Dy(3+) samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, UV-vis diffuse reflectance spectroscopy and photoluminescence (PL). The XRD analysis confirms the wurtzite structure of ZnO. A slight shift to lower angles, of the (101) peak, is seen with Dy(3+) content, indicating the substitution of these ions into the ZnO lattice. Raman study indicates the good crystallinity of all ZnO:Dy(3+) samples and confirms the substitution of Zn(2+) by Dy(3+). The band gap energy was found to increase then decrease with Dy content. The PL excitation spectra (PLE) of Dy(3+) showed six excitation bands with hypersensitive at 346nm ((6)H15/2→(6)P7/2). PL spectra show principally three emission bands relatives to (4)F9/2→(6)H15/2 (476nm), (4)F9/2→(6)H13/2 (567nm) and (4)F9/2→(6)H11/2 (658nm) transitions. The concentration dependency of PL intensity indicates a quenching for Dy(3+) concentration above 0.5at.%. The PL lifetime of (4)F9/2 metastable state was measured and discussed for all Dy content in ZnO. The temperature dependency of PL intensity is investigated for ZnO:Dy (0.5%) sample and the activation energy is determined. The CIE chromaticity color coordinate shows that ZnO:Dy(3+) can be useful for white luminescence applications.

  9. Photoluminescence of atomic layer deposited ZrO{sub 2}:Dy{sup 3+} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kiisk, Valter, E-mail: valter.kiisk@ut.ee; Tamm, Aile; Utt, Kathriin; Kozlova, Jekaterina; Mändar, Hugo; Puust, Laurits; Aarik, Jaan; Sildos, Ilmo

    2015-05-29

    Atomic layer deposition based on alternate cycling of ZrCl{sub 4}, Dy(thd){sub 3} and H{sub 2}O as precursors was applied for preparation of nanocrystalline ZrO{sub 2}:Dy thin films. Photoluminescence (PL) properties of Dy{sup 3+} in the ZrO{sub 2} films were studied at several laser excitations. Substantial activation of Dy{sup 3+} PL required thermal treatment at 900 °C. As a result of annealing, thinner (~ 80 nm) films with higher Dy content retained relatively high amount of tetragonal phase and remained crack-free. In thicker (~ 140 nm) films, considerable amount of monoclinic phase was formed and a peculiar microscale cracking pattern was developed along with phase segregation. It is demonstrated that the crystal structure of ZrO{sub 2} significantly influences the Dy{sup 3+} emission spectrum and, at least for ZrO{sub 2}-type matrices, Dy{sup 3+} is an excellent luminescent microprobe in comparison with micro-Raman scattering. A Förster-like PL decay profile allowed a conclusion that the self-quenching due to cross-relaxation between Dy{sup 3+} ions had a marked impact on emission intensity. - Highlights: • Atomic layer deposition of luminescent Dy-doped ZrO{sub 2} thin films was demonstrated. • Dy{sup 3+} luminescence was significantly activated only after high-temperature annealing. • Correlation between luminescent and structural properties was obtained. • Dy{sup 3+} luminescent probe showed superior performance compared to Raman-scattering. • Presence of several quenching processes was deduced from luminescence behavior.

  10. Spectroscopic properties of Dy3 + doped ZnO for white luminescence applications

    Science.gov (United States)

    Amira, Guesmi; Chaker, Bouzidi; Habib, Elhouichet

    2017-04-01

    Undoped and Dy3 + (0.25, 0.5, 0.8 and 1.5 at.%) doped ZnO were elaborated by solid-state reaction method. The ZnO:Dy3 + samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, UV-vis diffuse reflectance spectroscopy and photoluminescence (PL). The XRD analysis confirms the wurtzite structure of ZnO. A slight shift to lower angles, of the (101) peak, is seen with Dy3 + content, indicating the substitution of these ions into the ZnO lattice. Raman study indicates the good crystallinity of all ZnO:Dy3 + samples and confirms the substitution of Zn2 + by Dy3 +. The band gap energy was found to increase then decrease with Dy content. The PL excitation spectra (PLE) of Dy3 + showed six excitation bands with hypersensitive at 346 nm (6H15/2 → 6P7/2). PL spectra show principally three emission bands relatives to 4F9/2 → 6H15/2 (476 nm), 4F9/2 → 6H13/2 (567 nm) and 4F9/2 → 6H11/2 (658 nm) transitions. The concentration dependency of PL intensity indicates a quenching for Dy3 + concentration above 0.5 at.%. The PL lifetime of 4F9/2 metastable state was measured and discussed for all Dy content in ZnO. The temperature dependency of PL intensity is investigated for ZnO:Dy (0.5%) sample and the activation energy is determined. The CIE chromaticity color coordinate shows that ZnO:Dy3 + can be useful for white luminescence applications.

  11. Giant magnetocaloric effect in GdAlO3 and a comparative study with GdMnO3

    Science.gov (United States)

    Mahana, Sudipta; Manju, U.; Topwal, D.

    2017-01-01

    The magnetic properties and magnetocaloric effect of polycrystalline GdAlO3 and GdMnO3 have been investigated to assess their potential usage as magnetic refrigerants at cryogenic temperatures. These compounds undergo antiferromagnetic transitions at low temperatures which are associated with the giant magnetic entropy change effect (-\\bigtriangleup {{S}M} )  ˜40.9 J Kg · K-1 under a field change of 0-9 T for GdAlO3 while the moderate effect of 18 J Kg · K-1 is observed for polycrystalline GdMnO3. Though the relative cooling power of both the stated materials is similar however, the absence of magnetic and thermal hysteresis makes GdAlO3 a more efficient magnetic refrigerant than GdMnO3.

  12. DyCl3-NaCl体系相图的热力学优化计算%Thermodynamic Optimization of DyCl3 -NaCl System

    Institute of Scientific and Technical Information of China (English)

    叶信宇; 孙益民; 张静; 谈君君

    2005-01-01

    In this paper, the phase diagram of the DyCl3-NaC1 system is optimized and calculated with CALPHAD (calculation of phase diagram) technology. A set of thermodynamic functions of compounds Na3 DyCl6, NaDyCl4, and NaDy2 Cl7 have been optimized and calculated based on an interactive computer-assisted analysis. The optimized thermodynamic parameters, calculated phase diagram and experimental phase diagram are thermodynamically self-consistent.

  13. CanthebiliaryenhancementofGd-EOB-DTPA predictthedegreeofliverfunction?

    Institute of Scientific and Technical Information of China (English)

    Masahiro Okada; Kazunari Ishii; Kazushi Numata; Tomoko Hyodo; Seishi Kumano; Masayuki Kitano; Masatoshi Kudo; Takamichi Murakami

    2012-01-01

    BACKGROUND: Excretion of gadolinium-ethoxybenzyl-diethyl-enetriamine pentaacetic acid (Gd-EOB-DTPA) in the bile may be related to liver function, because of elimination from the liver after preferential uptake by hepatocytes. The purpose of this study was to investigate the relation between liver and biliary enhancement in patients with or without liver dysfunction, and to compare the tumor-to-liver contrast in these patients. METHODS: Forty patients [group 1: normal liver and Child-Pugh class A in 20 patients, group 2:Child-Pugh class B in 18 patients and Child-Pugh C in 2] were evaluated. All patients underwent MR imaging of the liver using a 1.5-Tesla system. T1-weighted 3D images were obtained at 5, 10, 15 and 20 minutes after Gd-EOB-DTPA injection. The relation between group 3 (total bilirubin RESULTS:Liver enhancement showed signiifcant difference at all time points between groups 1 and 2. Biliary enhancement did not show a signiifcant difference between groups 1 and 2 at 5 minutes, but did at 10, 15 and 20 minutes. At 20 minutes, signiifcant differences between groups 3 and 4 were seen for liver and biliary enhancement. At all time points, liver enhancement correlated with biliary enhancement in both groups. At 5 minutes and 20 minutes, statistical differences between groups 1 and 2 were seen for tumor-to-liver ratio. CONCLUSIONS: The degree of biliary enhancement has a close correlation to that of liver enhancement. It is especially important that insufifcient liver enhancement causes lower tumor-to-liver contrast in the hepatobiliary phase of Gd-EOB-DTPA.

  14. Half Life Measurements in {sup 155}Gd

    Energy Technology Data Exchange (ETDEWEB)

    Malmskog, S.G.

    1966-08-15

    In the literature there exists a definite difference for the half life of the 86.5 keV level in Gd depending on whether {sup 155}Eu or {sup 155}Tb sources have been used. Using a good energy resolution electron-electron coincidence spectrometer and a {sup 155}Eu source, a half life of 6.48 {+-} 0.26 nsec was obtained for the 86.5 keV level. This is in agreement with the values previously measured with {sup 155}Tb sources. The half life of the 105.4 keV level was measured to be 1.12 {+-} 0.05 nsec.

  15. Atomic transition probabilities of Gd i

    Science.gov (United States)

    Lawler, J. E.; Bilty, K. A.; Den Hartog, E. A.

    2011-05-01

    Fourier transform spectra are used to determine emission branching fractions for 1290 lines of the first spectrum of gadolinium (Gd i). These branching fractions are converted to absolute atomic transition probabilities using previously reported radiative lifetimes from time-resolved laser-induced-fluorescence measurements (Den Hartog et al 2011 J. Phys. B: At. Mol. Opt. Phys. 44 055001). The wavelength range of the data set is from 300 to 1850 nm. A least squares technique for separating blends of the first and second spectra lines is also described and demonstrated in this work.

  16. The effect of Gd doping on the electrical and photoelectrical properties of Gd:ZnO/p-Si heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Baturay, Silan [Department of Physics, Faculty of Science, Dicle University, 21280 Diyarbakir (Turkey); Ocak, Yusuf Selim, E-mail: yusufselim@gmail.com [Department of Science, Faculty of Education, Dicle University, 21280 Diyarbakir (Turkey); Science and Technology Application and Research Center, Dicle University, 21280 Diyarbakir (Turkey); Kaya, Derya [Department of Physics, Institute of Natural Applied Sciences, Dicle University, 21280 Diyarbakir (Turkey)

    2015-10-05

    Highlights: • Undoped and Gd doped ZnO thin films were deposited onto p-Si semiconductor. • The Gd:ZnO/p-Si heterojunctions were compared with undoped ZnO/p-Si heterojunction. • A strong effect of Gd doping on the performance of the devices were reported. - Abstract: Undoped ZnO thin films, as well as 1%, 3% and 5% Gd-doped ZnO films, were deposited on p-type Si using spin coating. The structural properties of these thin films were analysed using X-ray diffraction, and the current–voltage (I–V) and capacitance–voltage (C–V) characteristics of the Gd:ZnO/p-Si heterojunctions were compared with those of the undoped ZnO/p-Si heterojunctions. We found that Gd doping had a strong effect on the performance of the devices, and that the Gd:ZnO/p-Si heterojunctions formed with 1% Gd-doped ZnO were the most strongly rectifying, and had the highest barrier height and the lowest series resistance. Furthermore, the I–V measurements of the 1% Gd-doped ZnO/p-Si heterojunction exhibited the strongest response to light.

  17. In silico data analyses of recombinases GdDMC1A and GdDMC1B from Giardia duodenalis

    OpenAIRE

    2016-01-01

    Giardia duodenalis is a worldwide protozoa known causing diarrhea in all vertebrates, humans among these. Homologous recombination is a mechanism that provides genomic stability. Two putative recombinases were identified in G. duodenalis genome: GdDMC1A and GdDMC1B. In this article, we describe the identification of conserved domains in GdDMC1A and GdDMC1B, such as: DNA binding domains (Helix-turn-helix motif, loops 1 and 2) and an ATPcap and Walker A and B motifs associated with ATP binding ...

  18. Heat capacity of the frustrated magnetic pyrochlores Gd2Zr2O7 and Gd2Hf2O7

    Science.gov (United States)

    Durand, Alice M.; Klavins, Peter; Corruccini, L. R.

    2008-06-01

    The heat capacities of Gd2Zr2O7 and Gd2Hf2O7 both show sharp peaks in the vicinity of 0.77 K, consistent with the existence of long range magnetic order. They are superimposed in both cases on broader maxima centered at approximately 1 K, presumably due to short range spin correlations. Both compounds exhibit antiferromagnetic interactions, with Weiss constants of approximately -7 K. Comparisons are made to earlier results for the isomorphic compounds Gd2Ti2O7 and Gd2Sn2O7.

  19. Design netradičního sedacího prvku městského mobiliáře

    OpenAIRE

    Haltof, Vladimír

    2014-01-01

    Disertační práce se zabývá designem sedacího prvku městského mobiliáře (lavičky) sloučením pohledů dvou příbuzných oborů – průmyslového designu a architektury. Tvůrčí výstupy práce, které reagují na problémy městského mobiliáře v urbanistickém prostoru, byly od samého počátku cíleny jako design s ambicí reálné produkce. Proto je součástí práce několik ověřovacích kroků potvrzujících realizovatelnost navržených řešení. Prvním výstupem je design sedacího prvku inovativní koncepce s netradičním ...

  20. Surface characterization and luminescence properties of AlN doped with RE elements (Sm, Ho, Gd, Tm)

    OpenAIRE

    Balogun, Ismail Ayodele

    2015-01-01

    Rare‐ earth (RE)‐doped III‐nitride broad band‐gap semiconductors have attracted enormous interest as a foundation for optoelectronics devices, which combine the unique luminescence feature of Rare‐earth ions with the electronic properties of the semiconductors. Recent progress toward nitride‐based light emitting diode and light emitting due to electric current devices have been made using crystalline and amorphous AlN and GaN doped with a different lanthanide elements. The Rare‐earth...

  1. 信息动态%Spectral Analysis of Ho3+ -doped and Ho3+, Yb3+, Er3+ Co-doped Up-conversion Luminescence Borosilicate Glass

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A series of holmium ions doped borosilicate glass, including Ho3+ -doped, Ho3+/ Er3+ -doped, Ho3+/ Y Yb3+-doped and Ho3 Yb3 YEr3+ -doped galss, have been prepared by high-temperature melting. The up-conversion excitation spectra and emission spectra of the samples decrease. The analysis result reveals that both the intensities of excitation spectra and emission spectra were weaken with the Ho3+ concentration. The spectral intensities of Ho3+/Yb3+ -doped borosilicate glass increase with the increase of Ho3+ concentration because of the sensitization of Yb3+. The excitation and emission spectra intensities of Ho3+/Yb3 +/Er3+-doped borosilicate glass are weak, and the reason is the energy transfers from Ho3+ ions to Er3+ ions through energy resonant transfer process. Meanwhile the luminescence mechanism of broadband emission peaked at 550 nm is analyzed.

  2. Thermochemical investigations in the system Cd–Gd

    Energy Technology Data Exchange (ETDEWEB)

    Reichmann, Thomas L., E-mail: thomas.reichmann@univie.ac.at [Department of Inorganic Chemistry (Materials Chemistry), University of Vienna, 1090 Vienna (Austria); Ganesan, Rajesh [Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India); Ipser, Herbert [Department of Inorganic Chemistry (Materials Chemistry), University of Vienna, 1090 Vienna (Austria)

    2014-10-15

    Highlights: • Vapour pressures of Cd were determined in Cd-Gd alloys. • Thermodynamic activities of Cd are given between 52 and 86 at.% Cd. • Enthalpies of mixing of Cd were determined as a function of composition. • Gibbs energies of formation are given at 773 K. - Abstract: Vapour pressure measurements were performed in terms of a non-isothermal isopiestic method to determine vapour pressures of Cd in the system Cd–Gd between 693 and 1045 K. From these results thermodynamic activities of Cd were derived as a function of temperature for the composition range 52–86 at.% Cd. By employing an adapted Gibbs–Helmholtz equation, partial molar enthalpies of mixing of Cd were obtained for the corresponding composition range, which were used to convert the activity values of Cd to a common average sample temperature of 773 K. The relatively large variation of the activity across the homogeneity ranges of the phases Cd{sub 2}Gd and Cd{sub 45}Gd{sub 11} indicates that they probably belong to the most stable intermetallic compounds in this system. An activity value of Gd for the two phase field Cd{sub 6}Gd+L was available from literature and served as an integration constant for a Gibbs–Duhem integration. Integral Gibbs energies are presented between 51 and 100 at.% Cd at 773 K, referred to Cd(l) and α-Gd(s) as standard states. Gibbs energies of formation for the exact stoichiometric compositions of the phases Cd{sub 58}Gd{sub 13}, Cd{sub 45}Gd{sub 11}, Cd{sub 3}Gd and Cd{sub 2}Gd were obtained at 773 K as about −19.9, −21.1, −24.8, and −30.0 kJ g atom−{sup 1}, respectively.

  3. Polytypic phase formation in DyAl sub 3 by rapid solidification

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y.; Altounian, Z.; Muir, W.B. (Centre for the Physics of Materials and the Department of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada (CA))

    1991-01-14

    Amorphous ribbons of Al{sub {ital x}}Dy{sub 100{minus}{ital x}}, 93{gt}{ital x}{gt}85, were obtained by melt spinning. During crystallization, in addition to Al, four different metastable crystalline phases of DyAl{sub 3} were observed. These phases are, in order of appearance, the high-pressure face-centered cubic phase, {gamma}-DyAl{sub 3} and three polytypic rhombohedral phases, {beta}-DyAl{sub 3}, {beta}{prime}-DyAl{sub 3}, and {alpha}{prime}-DyAl{sub 3}. It is the first time that the {beta}{prime} phase in rare-earth trialuminides and the {alpha}{prime} phase in Dy-Al alloy system have been observed. It is shown that all these phases are associated with the polytypic packing of the hexagonal DyAl{sub 3} atomic layers. The relative stability of the phases is found to be related to the hexagonal to cubic stacking ratio in the structure.

  4. Evaluation of the exchange interaction and crystal fields in a prototype Dy2 SMM

    Science.gov (United States)

    Zhang, Qing; Sarachik, Myriam; Baker, Michael; Chen, Yizhang; Kent, Andrew; Pineda, Eufemio; McInnes, Eric

    In order to gain an understanding of the INS and magnetization data obtained for Dy2, the simplest member of a newly synthesized family of dysprosium-based molecular magnets, we report on calculations of the magnetic behavior of a Dy2 cluster with the formula [hqH2][Dy2(hq)4(NO3)3].MeOH. The molecular complex contains one high symmetry Dy(III) ion and one low symmetry Dy(III) ion. Our calculations suggest that exchange coupling between the two ions controls the behavior of the magnetization at low temperature, while the crystal field of the low symmetry Dy(III) ion controls the behavior at higher temperature. A point charge electrostatic model, based on crystallographic coordinates, provides a starting point for the determination of the crystal field. Parameters in these calculations are adjusted to provide best fits to inelastic neutron scattering data (INS) and low temperature magnetometry: the INS measurements access crystal field energies and low temperature magnetization probes the Dy-Dy exchange interaction. Work supported by ARO W911NF-13-1-1025 (CCNY) and NSF-DMR-1309202 (NYU).

  5. 26 CFR 48.4082-1 - Diesel fuel and kerosene; exemption for dyed fuel.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Diesel fuel and kerosene; exemption for dyed..., Tread Rubber, and Taxable Fuel Taxable Fuel § 48.4082-1 Diesel fuel and kerosene; exemption for dyed... fuel or kerosene if— (1) The person otherwise liable for tax is a taxable fuel registrant; (2) In the...

  6. Large magneto-optical effect in low-temperature-grown GaDyN

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.K.; Emura, S.; Hasegawa, S.; Asahi, H. [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2011-07-15

    GaDyN layers were grown at temperatures at 300 C by radio-frequency plasma-assisted molecular-beam epitaxy on sapphire substrates. X-ray diffraction results showed no obvious secondary phase in the GaDyN samples. A sharp line was found at 582.4 nm in the photoluminescence spectra from the low-temperature-grown samples, which was assigned intra-4f orbital transition: {sup 4}F{sub 9/2} - {sup 6}H{sub 13/2} of Dy{sup 3+} ion. It was shown that Dy atoms were incorporated into the Ga sites in these GaDyN layers. Magnetic circular dichroism (MCD) measurement was performed for these samples at 10 K to investigate magneto-optical effect. It was found that the large magneto-optical effect in the GaDyN depend on the Dy concentration. It is the evidence of ferromagnetic s -f exchange coupling in the GaDyN, which enhance the Zeeman splitting. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Performance of Brazilian thermoluminescent CaSO{sub 4}: Dy pellets in standard diagnostic radiology beams

    Energy Technology Data Exchange (ETDEWEB)

    Maia, A.F.; Caldas, L.V.E. [Instituto de Pesquisas Energeticas e Nucleares, Comissao Nacional de Energia Nuclear, Av. Prof. LIneu Prestes, 2242 Sao Paulo (Brazil)]. e-mail: afmaia@ipen.br

    2006-07-01

    The high sensitivity of CaSO{sub 4}: Dy as a thermoluminescent material is a great advantage when dealing with low dose levels, as in diagnostic radiology procedures. However, these kinds of dosemeters present a high energy dependence that must be precisely determined in the energy range of interest. Dosimetric pellets of CaSO{sub 4}: Dy are produced at IPEN since the end of the 80 Th decade. These pellets are produced in three forms: conventional CaSO{sub 4}: Dy (50 mg); thin CaSO{sub 4}: Dy (20 mg) and CaSO{sub 4}: Dy + 10% C (20 mg). The main applications of these dosemeters are in personal and environmental dosimetry. In this study, CaSO{sub 4}: Dy pellets produced at IPEN were evaluated in diagnostic radiology standard beams. These qualities are based on the IEC 61267 standard, and they were established at an industrial X-ray system Pantak/Seifert, model ISOVOLT 160HS. Former studies evaluated CaSO{sub 4}: Dy of different origins in diagnostic beams. In this study, a large energy interval was used to include computed tomography energy beams. The results obtained show the behavior of the IPEN CaSO{sub 4}: Dy pellets in diagnostic standard beams. All results confirm that these pellets may be used for dosimetric procedures in diagnostic radiology beams. (Author)

  8. Luminescent characteristics of CaSO{sub 4}:Dy films obtained by spray pyrolysis method

    Energy Technology Data Exchange (ETDEWEB)

    Roman, J., E-mail: holand_jeos@hotmail.com [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria-IPN, Av. Legaria 694, Col. Irrigacion, Mexico, D.F. 11500 (Mexico); Rivera, T.; Lozano, I.B. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria-IPN, Av. Legaria 694, Col. Irrigacion, Mexico, D.F. 11500 (Mexico); Sosa, R. [Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco186, Col. Vicentina, Mexico, D.F., 09340 (Mexico); Alarcon, G. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria-IPN, Av. Legaria 694, Col. Irrigacion, Mexico, D.F. 11500 (Mexico)

    2012-07-15

    The present paper reports the experimental results of dysprosium doped calcium sulphate (CaSO{sub 4}:Dy) films deposited by spray pyrolysis method. CaSO{sub 4}:Dy films were deposited on three different surfaces: glass, aluminum and quartz substrates at temperatures in the range from 450 to 600 Degree-Sign C. Structural and morphological characteristics of CaSO{sub 4}:Dy films were observed. Thermoluminescent characteristics of films were determined by irradiating ultraviolet energy region. Thermoluminescent glow curve of CaSO{sub 4}:Dy films with glass and aluminum substrates showed a peak under environmental irradiation. Both TL response glow shape and intensity of CaSO{sub 4}:Dy films UV irradiated as a function of substrates were studied. - Highlights: Black-Right-Pointing-Pointer We carried out the preparation of calcium sulfate films doped with dysprosium (CaSO{sub 4}:Dy) by spray paralysis method. Black-Right-Pointing-Pointer SEM and EDS techniques were applied to study the surface topography and chemical composition of the CaSO{sub 4}:Dy films. Black-Right-Pointing-Pointer Thermoluminescent characteristics of films were determined by irradiating ultraviolet energy region. Black-Right-Pointing-Pointer The thermoluminescent response of CaSO{sub 4}:Dy films as a function of substrate was analyzed.

  9. Synthesis and Characterization of Hollow Magnetic Alloy (GdNi2, Co5Gd Nanospheres Coated with Gd2O3

    Directory of Open Access Journals (Sweden)

    Wang Li

    2014-01-01

    Full Text Available Uniform magnetic hollow nanospheres (GdNi2, Co5Gd coated with Gd2O3 have been successfully prepared on a large scale via a urea-based homogeneous precipitation method using silica (SiO2 spheres as sacrificed templates, followed by subsequent heat treatment. Nitrogen sorption measurements and scanning electron microscope reveal that these hollow-structured magnetic nanospheres have the mesoporous shells that are composed of a large amount of uniform nanoparticles. After reduction treatment, these nanoparticles exhibit superparamagnetism that might have potential applications in medicine. Furthermore, the developed synthesis route may provide an important guidance for the preparation of other multifunctional hollow spherical materials.

  10. Dynamic parameters of Tb-Dy-Fe giant magnetostrictive alloy

    Institute of Scientific and Technical Information of China (English)

    白夏冰; 蒋成保

    2010-01-01

    Tb0.3Dy0.7Fe1.90 oriented rods were prepared by zone melting with unidirectional solidification.The magnetomechanical coupling factor(k33) was measured by magnetomechanical resonance under different DC bias fields up to 77.4 mT.An effective method was provided to calculate sonic velocity,elastic modulus and compliance constant through measuring resonate frequency(fr),and calculate dynamic magnetostriction(d33) via measuring magnetic permeability,magnetomechanical coupling factor(k33) and compliance co...

  11. Parametric models of reflectance spectra for dyed fabrics

    Science.gov (United States)

    Aiken, Daniel C.; Ramsey, Scott; Mayo, Troy; Lambrakos, Samuel G.; Peak, Joseph

    2016-05-01

    This study examines parametric modeling of NIR reflectivity spectra for dyed fabrics, which provides for both their inverse and direct modeling. The dye considered for prototype analysis is triarylamine dye. The fabrics considered are camouflage textiles characterized by color variations. The results of this study provide validation of the constructed parametric models, within reasonable error tolerances for practical applications, including NIR spectral characteristics in camouflage textiles, for purposes of simulating NIR spectra corresponding to various dye concentrations in host fabrics, and potentially to mixtures of dyes.

  12. Phase Transitions above the Yrast Line in {sup 154}Dy

    Energy Technology Data Exchange (ETDEWEB)

    Ma, W. C. [Mississippi State University, Mississippi State, Mississippi 39762 (United States); Martin, V. [Analisis Numerico, Facultad de Informatica, Universidad Politecnica de Madrid, E-28660 Madrid, (Spain); Khoo, T. L. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Lauritsen, T. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Egido, J. L. [Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, E-28049 Madrid, (Spain); Ahmad, I. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Bhattacharyya, P. [Purdue University, West Lafayette, Indiana 47907 (United States); Carpenter, M. P. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Daly, P. J. [Purdue University, West Lafayette, Indiana 47907 (United States); Grabowski, Z. W. [Purdue University, West Lafayette, Indiana 47907 (United States)] (and others)

    2000-06-26

    Spectra of the E2 quasicontinuum {gamma} rays feeding different spin regions of the {sup 154}Dy yrast line have been extracted. These are compared with corresponding theoretical spectra obtained by numerical simulations based on temperature-dependent Hartree-Fock theory, with thermal shape fluctuations. In this manner, different regions of the spin-energy plane can be examined. The results support the predictions of a smeared-out phase transition at high spin above the yrast line. (c) 2000 The American Physical Society.

  13. Quadrupole moments in chiral material DyFe3(BO3)4 observed by resonant x-ray diffraction

    Science.gov (United States)

    Nakajima, Hiroshi; Usui, Tomoyasu; Joly, Yves; Suzuki, Motohiro; Wakabayashi, Yusuke; Kimura, Tsuyoshi; Tanaka, Yoshikazu

    2016-04-01

    By means of circularly polarized x rays at the Dy L3 and Fe K absorption edges, the chiral structure of the electric quadrupole was investigated for a single crystal of DyFe3(BO3)4, in which both Dy and Fe ions exhibit a spiral arrangement. The integrated intensity of the resonant x-ray diffraction of space-group forbidden reflections 004 and 005 is interpreted within the electric dipole transitions from Dy 2 p3/2 to 5 d and Fe 1 s to 4 p , respectively. We have confirmed that the handedness of the crystal observed at Dy L3 and Fe K edges is consistent with that observed at Dy M5 edge reported in a previous study. The electric quadrupole moments of Dy 5 d and Fe 4 p are derived by analyzing the azimuth scans of the diffracted intensity. The temperature profiles of the integrated intensity of 004 at the Dy L3 and the Fe K edges are similar to those of Dy-O and Fe-O bond lengths, while the temperature dependence at the Dy M5 edge does not match the bond-length behavior. The results indicate that the helix chiral orientations of quadrupole moments due to Dy 5 d and Fe 4 p electrons are more strongly coupled to the ligands states than Dy 4 f electrons.

  14. Roles of Eu2+, Dy3+ Ions in Persistent Luminescence of Strontium Aluminates Phosphors

    Institute of Scientific and Technical Information of China (English)

    L(U) Xingdong; ZHONG Minjuan; WANG Renqin

    2008-01-01

    The polycrystalline Eu2+ and Dy3+ co-doped strontium aluminates SrAl2O4: Eu2+,Dy3+ with different compositions were prepared by solid state reactions. The UV-excited photoluminescence, persistent luminescence and thermo-luminescence were studied and compared. Results show that the doped Eu2+ ion in SrAl2O4: Eu2+, Dy3+phosphors works as not only the UV-excited luminescent center but also the persistent luminescent center. The doped Dy3+ ion can hardly yield any luminescence under UV-excitation, but effectively enhance the persistent luminescence and thermo-luminescence of SrAl2O4: Eu2+. Dy3+ co-doping can help form electron traps with appropriate depth due to its suitable electro-negativity, and increase the density and depth of electron traps. Based on above observations, a persistent luminescence mechanism, electron transfer model, is proposed and illustrated.

  15. Effects of Dy on cyclic oxidation resistance of NiAl alloy

    Institute of Scientific and Technical Information of China (English)

    GUO Hong-bo; WANG Xiao-yan; LI Ji; WANG Shi-xing; GONG Sheng-kai

    2009-01-01

    The NiAl alloys modified by reactive element(RE), dysprosium(Dy), were produced by arc melting. The microstructures of the modified alloys were investigated by field emission-scanning electron microscope(FE-SEM) equipped with energy dispersive spectroscope(EDS) and back scatter detector. Cyclic oxidation tests at 1 200 ℃ were conducted to assess the cyclic oxidation performance of the alloys. The Dy dopant prevents the surface rumpling of the oxide scale and the formation of cavities beneath the oxide scale. The pegs consisting of Dy-rich oxide inclusion core and an outer alumina sheath develop deeply in the alloy and improve the oxide scale adhesion. 0.05%-0.1% (molar fraction) Dy dramatically improves the cyclic oxidation resistance of the NiAl alloy. Too high concentration of Dy is deleterious because of the fast oxidation rate caused by severe internal oxidation.

  16. Photoluminescence and thermoluminescence studies of CaAl2O4:Dy(3+) phosphor.

    Science.gov (United States)

    Ziyauddin, Mohammad; Tigga, Shalinta; Brahme, Nameeta; Bisen, D P

    2016-02-01

    Calcium aluminate phosphors activated by Dy(3+) have been prepared by a combustion method at a temperature of 600°C. Photoluminescence (PL) and thermoluminescence (TL) properties of gamma-irradiated Dy-doped calcium aluminate were investigated. The PL spectrum shows a broad peak around 488 nm and 573 nm, under 347 nm excitation. Thermoluminescence studies were performed for different concentrations of Dy. Optimum intensity of photoluminescence was found for 0.02 mol% concentration of Dy. It was found that initially the peak TL intensity increases with increasing concentration of Dy in the CaAl2O4 host, attains a maximum value for 0.05 mol% concentration and decreases with further increase in the doping concentration due to concentration quenching. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Luminescence properties of Dy3+ doped lanthanum-calcium-silicaborate glass scintillator

    Science.gov (United States)

    Park, J. M.; Ha, D. H.; Lee, S. W.; Chanthima, N.; Ruangtaweep, Y.; Kaewkhao, J.

    2016-09-01

    In this research Dy3+-doped lanthanum-calcium-silicaborate glass scintillators, with the formula 25La2O3: 10CaO: 10SiO2: (55-x)B2O3: xDy2O3, were fabricated by using the melt-quenching technique. For the Dy3+ doping concentrations from 0.05 mol% to 0.5 mol% studied the luminescence properties of the Dy3+-doped glass scintillators with various radiation sources, such as X-ray, photo-, laser, and proton. To understand the absorption state, we measured the transmittance spectrum. Furthermore, X-ray, photo- and proton-induced emission spectra were measured to study the transition states of Dy3+-doped glass scintillators. The laser-induced emission spectra were measured at low temperatures in the range from 10 K to 300 K.

  18. Preparation of DyFe2 and TbFe2 by Reduction-Diffusion Process

    Institute of Scientific and Technical Information of China (English)

    Guangsi GUO; Guangtai WANG; Zhitong SUI

    2004-01-01

    The pure intermetallic compounds (Tb1-xDyx)Fe2 are super-magnetostriction materials, which were produced from DyFe2and TbFe2 in this paper. The thermodynamic possibility and kinetic feasible conditions for DyFe2 and TbFe2 preparation by reduction-diffusion in Ca-Dy2O3-Fe and Ca-Tb4O7-Fe systems were analyzed and the products of DyFe2 and TbFe2 were confirmed by XRD. The contracting core model was applied to describe the reduction-diffusion process in which the diffusion is a rate-controlled step. The apparent activation energies of DyFe2 and TbFe2 processes are 45 and 39 k J/mol respectively.

  19. DyP-type peroxidases comprise a novel heme peroxidase family.

    Science.gov (United States)

    Sugano, Y

    2009-04-01

    Dye-decolorizing peroxidase (DyP) is produced by a basidiomycete (Thanatephorus cucumeris Dec 1) and is a member of a novel heme peroxidase family (DyP-type peroxidase family) that appears to be distinct from general peroxidases. Thus far, 80 putative members of this family have been registered in the PeroxiBase database (http://peroxibase.isbsib.ch/) and more than 400 homologous proteins have been detected via PSI-BLAST search. Although few studies have characterized the function and structure of these proteins, they appear to be bifunctional enzymes with hydrolase or oxygenase, as well as typical peroxidase activities. DyP-type peroxidase family suggests an ancient root compared with other general peroxidases because of their widespread distribution in the living world. In this review, firstly, an outline of the characteristics of DyP from T. cucumeris is presented and then interesting characteristics of the DyP-type peroxidase family are discussed.

  20. Thermodynamic and Kinetic Study of Crystallization Reaction of Fe/Dy Multilayers Form Amorphous State

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To give further insight into the behavior of Fe/Dy multilayers in the crystallization from as-deposited amorphous state, free energy diagram of Fe/Dy system was constructed based on Miedema semiempirical theory. It is shown that the crystallization of amorphous films is controlled by both thermodynamic and kinetic conditions. The calculated free energies of crystalline Fe and Dy are significantly lower than those in the amorphous states, which provide thermodynamic driving force for crystallization. During annealing, the kinetic phase evolution of the multilayers is controlled by free energy barrier of nucleation and critical-size of new phase nucleus. Thus it explains the experimental results that Fe crystallites formed first followed by Dy grains, whereas crystalline Fe-Dy intermetallic compounds were not observed during annealing at moderate temperatures.

  1. Preparation of Dy-Bi alloy films by electrodeposition in organic bath

    Institute of Scientific and Technical Information of China (English)

    LI Gaoren; TONG Yexiang; LIU Guankun

    2004-01-01

    The cyclic voltammetry and potentiostatic electrolysis were used to investigate the preparing of Dy-Bi alloy films in LiCl-DMSO (dimethylsulfoxide) system. The effects of several factors including the potential of deposition, concentrations of main salts, and the concentration ratio of DyCl3 to Bi(NO3)3 were studied. Dy-Bi alloy films containing 4.82%-80.62% (mass fraction) dysprosium were prepared in DyCl3-Bi(NO3)3-LiCl-DMSO system by controlling the system composition and deposition conditions. The films are gray, uniform, metallic luster and adhere firmly to the copper substrates analyzed by SEM (scanning electron microscope), EDS (X-ray energy dispersive analysis), and XRD (X-ray diffraction). After heat treatment at 718 K for l h, the alloy phase of Dy-Bi was found in XRD patterns.

  2. Magnetic structure and magnetocalorics of GdPO4

    NARCIS (Netherlands)

    Palacios, E.; Rodriguez-Velamazan, J.A.; Evangelisti, M.; McIntyre, G.J.; Lorusso, G.; Visser, D.; De Jongh, L.J.; Boatner, L.A.

    2014-01-01

    The magnetic ordering structure of GdPO4 is determined at T=60 mK by the diffraction of hot neutrons with wavelength λ=0.4696 Å. It corresponds to a noncollinear antiferromagnetic arrangement of the Gd moments with propagation vector k=(1/2,0,1/2). This arrangement is found to minimize the dipole-di

  3. Preparation of ~(64)Ni-Gd-Cu Target

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The three-layer-sandwich targets of 64Ni-Gd-Cu needed in the physics experiment were prepared. The middle layers are thin ferromagnetic Gd layers of about 1.7 mg/cm2, recoil stopper layers are thick crystallized and defect-free Cu layers of about 12

  4. Effect of Gd3+ on the colloidal stability of liposomes.

    Science.gov (United States)

    Sabín, Juan; Prieto, Gerardo; Sennato, Simona; Ruso, Juan M; Angelini, Roberta; Bordi, Federico; Sarmiento, Félix

    2006-09-01

    Lanthanide ions such as La3+ and Gd3+ are well known to have large effects on the structure of phospholipid membranes. Unilamellar vesicles of dipalmitoylphosphatidylcholine (DPPC) were prepared by sonication method and confirmed by transmission electron microscopy. The effects of concentration of gadolinium ions Gd3+ on DPPC unilamellar vesicles in aqueous media were studied by different techniques. As physical techniques, photon correlation spectroscopy, electrophoretic mobility, and differential scanning calorimetry were used. The theoretical predictions of the colloidal stability of liposomes were followed using the Derjaguin-Landau-Verwey-Overbeek theory. Changes in the size of liposomes and high polydispersities values were observed as Gd3+ concentration increases, suggesting that this cation induces the aggregation of vesicles. Electrophoretic mobility measurements on unilamellar vesicles as a function of Gd3+ ion concentration show that the vesicles adsorb Gd3+ ions. Above Gd3+ concentrations of 0.1 mol dm-3, the zeta potential and light scattering measurements indicate the beginning of aggregation process. For comparison with similar phospholipids, the zeta potential of phosphatidylcholine interacting with Gd3+ was measured, showing an analogous behavior. Differential scanning calorimetry has been used to determine the effect of Gd3+ on the transition temperature (Tc) and on the enthalpy (DeltaHc) associated with the process.

  5. Developments in the Gung Ho dynamical core

    Science.gov (United States)

    Melvin, Thomas

    2017-04-01

    Gung Ho is the new dynamical core being developed for the next generation Met Office weather and climate model, suitable for meeting the exascale challenge on emerging computer architectures. It builds upon the earlier collaborative project between the Met Office, NERC and STFC Daresbury of the same name to investigate suitable numerical methods for dynamical cores. A mixed-finite element approach is used, where different finite element spaces are used to represent various fields. This method provides a number of beneficial improvements over the current model, such a compatibility and inherent conservation on quasi-uniform unstructured meshes, whilst maintaining the accuracy and good dispersion properties of the staggered grid currently used. Furthermore, the mixed finite element approach allows a large degree of flexibility in the type of mesh, order of approximation and discretisation, providing a simple way to test alternative options to obtain the best model possible.

  6. Tessellation of SoHO Magnetograms

    Indian Academy of Sciences (India)

    R. Srikant; Jagdev Singh

    2000-09-01

    A gradient based algorithm which divides arbitrary images into non-overlapping surface filling tiles of opposite polarity is used to study the flux and size distributions of large scale magnetic flux concentrations in solar and heliospheric observatory (SoHO) magnetograms. The mean absolute flux and size of the concentrations at the considered scale is found to be about 1.7 × 1018Mx and 5.2Mm for both polarities. The form of the flux distribution is characterized by a skewness of 3 = 4.9 and a kurtosis of 4, = 42.8. The fall in the distribution in the range 6.5 × 1017Mx to 5 × 1018Mx is described by an exponential fit, in agreement with a model for the sustenance of quiet region flux.

  7. Marketing internetového obchodu

    OpenAIRE

    Popolanský, Jiří

    2010-01-01

    V mé diplomové práci se budu zabývat tématem marketingu internetového obchodu. V teoretické části se zaměřím na nalezení vhodných nástrojů marketingové podpory. V praktické části zejména na analýzu současné situace v konkrétním podniku a vlastní návrh marketingové kampaně pro daný internetový obchod. In my master’s thesis I will deal with theme marketing for e-business. In theoretic part I focus on finding useful instruments for marketing subvention. In practical part especially on analysi...

  8. Coloring problem and magnetocaloric effect of Gd{sub 3}Co{sub 2.2}Si{sub 1.8}

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Jinlei, E-mail: materyao@gmail.com [Research Center for Solid State Physics and Materials, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Morozkin, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Mozharivskyj, Yurij [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer Gd{sub 3}Co{sub 2.2}Si{sub 1.8} adopts the Er{sub 3}Ge{sub 4} structure (space group Cmcm). Black-Right-Pointing-Pointer Si and Co show site preference. Black-Right-Pointing-Pointer The electronic factors determine the site occupation of Si and Co. Black-Right-Pointing-Pointer Gd{sub 3}Co{sub 2.2}Si{sub 1.8} order ferromagnetically below 172 K. - Abstract: The Gd{sub 3}Co{sub 2.2}Si{sub 1.8} compound was synthesized by arc melting the constituent elements and subsequent annealing at 1070 K for 120 h. It adopts the Dy{sub 3}Co{sub 2.2}Si{sub 1.8}-type structure with the space group Cmcm and the unit cell parameters of a = 4.1176(7) A, b = 10.305(2) A, c = 12.778(2) A and V = 542.2(2) A{sup 3}. The Co and Si atoms preferentially occupy the 8f and 4a/4c sites, respectively. The atomic electronegativity and electron density at a given site determine its site occupation, according to the analysis of the electronic structure. Gd{sub 3}Co{sub 2.2}Si{sub 1.8} orders ferromagnetically with the Curie temperature of 172 K. The isothermal magnetic entropy change, -{Delta}S{sub m}, reaches the maximum value of 7.09 J/kg K at 170 K for a field change of 0-50 kOe.

  9. Magnetic phase diagram of Tb{sub 3-x}Ho{sub x}Cu{sub 4}Sn{sub 4} system

    Energy Technology Data Exchange (ETDEWEB)

    SzytuLa, A., E-mail: andrzej.szytula@uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, PL-30-059 Krakow (Poland); Jaworska-GoLab, T. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, PL-30-059 Krakow (Poland); Nenkov, K. [Leibnitz Institute for Solid State and Materials Research, P.O. Box 270116, D-01 171 Dresden (Germany); International Laboratory of High Magnetic Fields and Low Temperatures, Gajowicka 95, PL-53-529 WrocLaw (Poland); Penc, B. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, PL-30-059 Krakow (Poland); Zarzycki, A. [H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, PL-31-342 Krakow (Poland)

    2012-03-15

    Magnetic phase diagram of Tb{sub 3-x}Ho{sub x}Cu{sub 4}Sn{sub 4} was determined on the basis of magnetic and heat capacity data. X-ray diffraction data proved that these compounds crystallize in the orthorhombic Gd{sub 3}Cu{sub 4}Ge{sub 4}-type structure. The compounds are antiferromagnets at low temperatures and the reciprocal magnetic susceptibility obeys the Curie-Weiss law. The paramagnetic Curie temperatures are negative and their absolute values decrease with increasing Ho content. An anomalous concentration dependence of the Neel temperature is observed. - Highlights: Black-Right-Pointing-Pointer Magnetic and heat capacity measurements of Tb{sub 3-x}Ho{sub x}Cu{sub 4}Sn{sub 4} show that T{sub N} is composition dependent. Black-Right-Pointing-Pointer Significant decrease of T{sub N} with x might be connected with the 2d Wyckoff position occupation. Black-Right-Pointing-Pointer Spin-glass like behavior is observed, indicating frustration of magnetic interactions.

  10. Structural and magnetic properties of C15 HoMn{sub 2} hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Budziak, A., E-mail: andrzej.budziak@ifj.edu.pl [H.Niewodniczanski Institute of Nuclear Physics PAN, ul. Radzikowskiego 152, 31-342 Krakow (Poland); Zachariasz, P. [Institute of Atomic Energy POLATOM, 05-400 Otwock-Swierk (Poland); Kolwicz-Chodak, L.; Figiel, H. [Faculty of Physics and Applied Computer Science, University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Pacyna, A. [H.Niewodniczanski Institute of Nuclear Physics PAN, ul. Radzikowskiego 152, 31-342 Krakow (Poland); Zukrowski, J. [Faculty of Physics and Applied Computer Science, University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland)

    2011-02-03

    Research highlights: > Full structural and magnetic phase diagrams are presented for the HoMn{sub 2}H{sub x}(0 < x {<=} 4.3) hydrides, where x = 4.3 is a typical maximal hydrogen concentration obtained for RMn{sub 2}H{sub x} (R: rare earth) under low pressure of H{sub 2} (ca {approx} 1 bar). > For x < {approx} 1.6: (1) The spinodal decompositions into two structurally different phases are observed. The lattice parameters of one of them correspond to those of the pure host HoMn{sub 2} material, while the lattice parameters of the other phase correspond to those of HoMn{sub 2}H{sub 1.6}. (2) Abundances of both phases change with hydrogen concentration x. (3) No intermediate phase appears, which is typical for other hydrides based on the C15 Laves phase type compounds (e.g. (Tb, Gd)Mn{sub 2}). Instead of that, structural transformations to monoclinic structures are observed. > For x = 2.5 splitting into two phases with different hydrogen concentrations x (x{sub 1} {approx} 2.3 and x{sub 2} {approx} 2.8) appears again, which was observed only for hydrides based on the C14 Laves phase type compounds (e.g. in (Sm, Er, Nd)Mn{sub 2}H{sub x}) in the range 2 < x < 3. > For samples with 2 < x < 2.2 no structural transformations are detected. > The effects of hydrogen absorption on structural properties are shown to be reflected in magnetic behavior. > A huge jump of magnetic ordering temperatures from {approx}24 K for HoMn{sub 2} to {approx} (200-380) K for its hydrides is observed. - Abstract: Powder samples of cubic HoMn{sub 2}H{sub x} hydrides, with 0 {<=} x {<=} 4.3, have been investigated by X-ray diffraction and AC/DC magnetometry as a function of temperature and external magnetic field. Hydrogen is demonstrated to strongly modify structural and magnetic properties. X-ray studies revealed many structural transformations placed at low temperatures. In particular, a transformation from the cubic to the monoclinic structure was detected, which so far has not been reported

  11. Complex magnetic behavior in GdCrO3

    Science.gov (United States)

    Mahana, Sudipta; Manju, U.; Topwal, D.

    2017-05-01

    Magnetic interactions in Gadolinium orthochromites (GdCrO3) are quite complex. It shows strong temperature dependency related to Gd3+-Gd3+, Gd3+-Cr3+ and Cr3+-Cr3+ interactions, resulting in exotic phenomena like spin flipping and spin reorientation. These behaviors are successfully explained by considering Cr 3d-Gd 4f magnetic coupling. The nearest neighbor symmetric and antisymmetric exchange coupling in Cr-sublattice was found to be Je = 11.058 K and D = 2.64 K from modified Curie-Weiss law modeled by Moriya, while positive Zeeman energy between net moments and the applied external magnetic fields was found to drive spin flipping.

  12. Ferrimagnetic properties of Co/(Gd-Co) multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Svalov, A.V. [Institute of Physics and Applied Mathematics, Ural State University, Lenin Avenue 51, 620083, Ekaterinburg (Russian Federation) and Departamento de Fisica, Universidad de Oviedo, Avenida Calvo Sotelo s/n, 33007, Oviedo, Asturias (Spain)]. E-mail: andrey.svalov@usu.ru; Fernandez, A. [Departamento de Fisica, Universidad de Oviedo, Avenida Calvo Sotelo s/n, 33007, Oviedo, Asturias (Spain); Vas' kovskiy, V.O. [Institute of Physics and Applied Mathematics, Ural State University, Lenin Avenue 51, 620083, Ekaterinburg (Russian Federation); Tejedor, M. [Departamento de Fisica, Universidad de Oviedo, Avenida Calvo Sotelo s/n, 33007, Oviedo, Asturias (Spain); Barandiaran, J.M. [Departamento de Electricidad y Electronica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, UPV/EHU, P.O. Box 644, 48080, Bilbao (Spain); Orue, I. [Departamento de Electricidad y Electronica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, UPV/EHU, P.O. Box 644, 48080, Bilbao (Spain); Kurlyandskaya, G.V. [Departamento de Electricidad y Electronica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, UPV/EHU, P.O. Box 644, 48080, Bilbao (Spain)

    2006-09-15

    Co/(Gd-Co) multilayers have been prepared by rf-sputtering and investigated by means of Transverse Magnetooptic Kerr Effect (TMOKE), SQUID and VSM magnetometry. The composition of amorphous Gd{sub 0.36}Co{sub 0.64} layers was chosen so that their saturation magnetization was dominated by Gd moments in all the temperature range. Co and Gd-Co layers formed a macroscopic ferrimagnetically coupled system displaying a compensation temperature. Complete magnetic moment compensation was found at such point. An inversion of TMOKE hysteresis loops and a divergent behaviour of coercivity were also observed. By changing the layers thickness it has been possible to control the magnetic characteristics of the Co/(Gd-Co) structures, in particular the compensation takes place at different temperatures.

  13. Peculiarities of neutron waveguides with thin Gd layer

    CERN Document Server

    Khaydukov, Yu; Progliado, V; Ustinov, V; Nikitenko, Yu; Keller, T; Aksenov, V; Keimer, B

    2015-01-01

    Peculiarities of the formation of a neutron enhanced standing wave in the structure with a thin highly absorbing layer of gadolinium are considered in the article. An analogue of the poisoning effect well known in reactor physics was found. The effect is stronger for the Nb/Gd/Nb system. Despite of this effect, for a Nb/Gd bilayer and a Nb/Gd/Nb trilayer placed between Al2O3 substrate and Cu layer, it is shown theoretically and experimentally that one order of magnitude enhancement of neutron density is possible in the vicinity of the Gd layer. This enhancement makes it possible to study domain formation in the Gd layer under transition of the Nb layer(s) into the superconducting state (cryptoferromagnetic phase).

  14. Thermochemical investigations in the system Cd-Gd.

    Science.gov (United States)

    Reichmann, Thomas L; Ganesan, Rajesh; Ipser, Herbert

    2014-10-15

    Vapour pressure measurements were performed in terms of a non-isothermal isopiestic method to determine vapour pressures of Cd in the system Cd-Gd between 693 and 1045 K. From these results thermodynamic activities of Cd were derived as a function of temperature for the composition range 52-86 at.% Cd. By employing an adapted Gibbs-Helmholtz equation, partial molar enthalpies of mixing of Cd were obtained for the corresponding composition range, which were used to convert the activity values of Cd to a common average sample temperature of 773 K. The relatively large variation of the activity across the homogeneity ranges of the phases Cd2Gd and Cd45Gd11 indicates that they probably belong to the most stable intermetallic compounds in this system. An activity value of Gd for the two phase field Cd6Gd+L was available from literature and served as an integration constant for a Gibbs-Duhem integration. Integral Gibbs energies are presented between 51 and 100 at.% Cd at 773 K, referred to Cd(l) and α-Gd(s) as standard states. Gibbs energies of formation for the exact stoichiometric compositions of the phases Cd58Gd13, Cd45Gd11, Cd3Gd and Cd2Gd were obtained at 773 K as about -19.9, -21.1, -24.8, and -30.0 kJ g atom-(1), respectively.

  15. Thermochemical investigations in the system Cd–Gd

    Science.gov (United States)

    Reichmann, Thomas L.; Ganesan, Rajesh; Ipser, Herbert

    2014-01-01

    Vapour pressure measurements were performed in terms of a non-isothermal isopiestic method to determine vapour pressures of Cd in the system Cd–Gd between 693 and 1045 K. From these results thermodynamic activities of Cd were derived as a function of temperature for the composition range 52–86 at.% Cd. By employing an adapted Gibbs–Helmholtz equation, partial molar enthalpies of mixing of Cd were obtained for the corresponding composition range, which were used to convert the activity values of Cd to a common average sample temperature of 773 K. The relatively large variation of the activity across the homogeneity ranges of the phases Cd2Gd and Cd45Gd11 indicates that they probably belong to the most stable intermetallic compounds in this system. An activity value of Gd for the two phase field Cd6Gd+L was available from literature and served as an integration constant for a Gibbs–Duhem integration. Integral Gibbs energies are presented between 51 and 100 at.% Cd at 773 K, referred to Cd(l) and α-Gd(s) as standard states. Gibbs energies of formation for the exact stoichiometric compositions of the phases Cd58Gd13, Cd45Gd11, Cd3Gd and Cd2Gd were obtained at 773 K as about −19.9, −21.1, −24.8, and −30.0 kJ g atom−1, respectively. PMID:25328283

  16. Apo A1 Mimetic Rescues the Diabetic Phenotype of HO-2 Knockout Mice via an Increase in HO-1 Adiponectin and LKBI Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Jian Cao

    2012-01-01

    Full Text Available Insulin resistance, with adipose tissue dysfunction, is one of the hallmarks of metabolic syndrome. We have reported a metabolic syndrome-like phenotype in heme oxygenase (HO-2 knockout mice, which presented with concurrent HO-1 deficiency and were amenable to rescue by an EET analog. Apo A-I mimetic peptides, such as L-4F, have been shown to induce HO-1 expression and decrease oxidative stress and adiposity. In this study we aimed to characterize alleviatory effects of HO-1 induction (if any on metabolic imbalance observed in HO-2 KO mice. In this regard, HO-2(−/− mice were injected with 2 mg/kg/day L-4F, or vehicle, i.p., for 6 weeks. As before, compared to WT animals, the HO-2 null mice were obese, displayed insulin resistance, and had elevated blood pressure. These changes were accompanied by enhanced tissue (hepatic oxidative stress along with attenuation of HO-1 expression and activity and reduced adiponectin, pAMPK, and LKB1 expression. Treatment with L-4F restored HO-1 expression and activity and increased adiponectin, LKB1, and pAMPK in the HO-2(−/− mice. These alterations resulted in a decrease in blood pressure, insulin resistance, blood glucose, and adiposity. Taken together, our results show that a deficient HO-1 response, in a state with reduced HO-2 basal levels, is accompanied by disruption of metabolic homeostasis which is successfully restored by an HO-1 inducer.

  17. Low temperature magnetic properties of geometrically frustrated Gd2Sn2O7 and Gd2Ti2O7

    Science.gov (United States)

    Bonville, P.; Hodges, J. A.; Ocio, M.; Sanchez, J. P.; Vulliet, P.; Sosin, S.; Braithwaite, D.

    2003-11-01

    We have examined the low temperature magnetic properties of the geometrically frustrated antiferromagnetic pyrochlores Gd2Sn2O7 and Gd2Ti2O7 using specific heat, 155Gd Mössbauer, magnetic susceptibility and magnetization measurements. For Gd2Sn2O7, the specific heat evidences a single, strongly first order magnetic transition near 1.0 K in Gd2Ti2O7, we confirm the presence of both the transition near 1.0 K and the second transition near 0.75 K. Below 1 K, magnetic irreversibilities are present in both compounds, but their signature (the difference between the FC and ZFC branches) is more marked in Gd2Sn2O7. At 0.03 K in each compound, the Mössbauer data show that the four Gd3+ of a tetrahedron carry moments of equal sizes and on a frequency scale of 120 × 106 s-1 each is oriented perpendicular to the local \\langle 111 \\rangle direction. In Gd2Ti2O7, the Mössbauer data also indicates that the transition at 0.75 K involves a small change in the magnetic structure.

  18. X-ray absorption and photoemission study of spin state and metal-insulator transition in GdBaCo{sub 2}O{sub 5.47}

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Z.; Wu Hua; Koethe, T.; Haverkort, M.W.; Burnus, T.; Gegner, J.; Zobel, C.; Lorenz, T.; Tjeng, L.H. [2. Physikalisches Inst., Univ. zu Koeln (Germany); Barilo, S.N. [Inst. of Solid State and Semiconductors Physics, National Academy of Sciences (Belarus); Lin, H.J.; Chen, C.T. [National Synchrotron Radiation Research Center, Tsinchu (China); Brookes, N.B. [European Synchrotron Radiation Facility (France)

    2007-07-01

    The fundamental physics of the magnetoresistance materials RBaCo{sub 2}O{sub 5.5} (R=Sm,Eu,Gd,Tb,Dy,Y), particularly the issue of spin-state and metal-insulator transition (MIT), is currently under intense debate. Using valence-baud photoemission spectra and X-ray absorption spectra at both the O-K and Co-L{sub 2,3} edges, we found that crossing the MIT, the band gap decreases but does not collapse across the MIT. More significantly, our spectroscopic evidence firmly rules out the widely accepted model for the low-temperate phase, namely that the Co{sup 3+} ions in the octahedral sites are mainly low spin and in the pyramidal sites intermediate spin. We rather found that the MIT in this system is very similar to the high temperature (600 K) MIT of LaCoO{sub 3}. (orig.)

  19. An epitope common to gangliosides O-acetyl-GD3 and GD3 recognized by antibodies in melanoma patients after active specific immunotherapy.

    Science.gov (United States)

    Ravindranath, M H; Morton, D L; Irie, R F

    1989-07-15

    GD3 is a major ganglioside of human melanoma and was shown to be an effective target for passive immunotherapy with murine monoclonal antibodies. It was noted earlier that GD3 neither purified nor in melanoma cell vaccine (MCV), could elicit an antibody response in melanoma patients. In this study, we demonstrate that melanoma patients who received MCV had autoantibodies against a derivative of GD3, O-acetylated GD3 (O-AcGD3), a minor ganglioside expressed on human melanoma cells, and that the antibodies cross-reacted with GD3. Thin layer chromatographic immunostaining revealed that all of the sera containing antibodies against O-AcGD3 also reacted to GD3. None of the other sera responded only to GD3, although the MCV contained 7- to 12-fold higher GD3 than O-AcGD3. Furthermore, the antibody activity was completely abolished by absorption with animal erythrocytes expressing either O-acetyl disialogangliosides or GD3, indicating that the antibodies recognize an epitope commonly shared by GD3 and O-AcGD3. The antibodies bound only to the sialyloligosaccharide moiety but not to the ceramide portion of GD3 after endoglycosylceramidase treatment. The antibodies failed to bind to GD3 after neuraminidase treatment. These results indicate that the sialyloligosaccharides of the gangliosides are important components of the epitope. Periodate oxidation abolished reactivity of the antibodies to GD3 but not that to O-AcGD3, revealing that the glycerol side chain of the sialic acids in both GD3s was an important structure of the epitope. The binding of the antibodies to melanoma cell surface gangliosides was confirmed by an absorption with a GD3- and O-AcGD3-positive melanoma cell line. These results in the light of previous reports on the inability of GD3 to elicit immune response in humans suggest that anti-GD3 antibodies found in the melanoma patients were induced by immunization with O-AcGD3 and O-AcGD3 present in the MCV would serve as an antigen source for GD3-targeted

  20. Magnetic rare earth superlattices

    DEFF Research Database (Denmark)

    Majkrzak, C.F.; Kwo, J.; Hong, M.;

    1991-01-01

    Advances in molecular beam epitaxy deposition techniques have recently made it possible to grow, an atomic plane at a time, single crystalline superlattices composed of alternating layers of a magnetic rare earth, such as Gd, Dy, Ho, or Er, and metallic Y, which has an identical chemical structure...