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Sample records for ba pb bi

  1. Tl, Bi, and Pb doping in Ba4BiPb2TlO12-δ

    International Nuclear Information System (INIS)

    Sutto, T.E.; Averill, B.A.

    1992-01-01

    To determine the effects of different 6s metal concentrations on the superconducting nature of Ba 4 BiPb 2 TlO 12-δ , materials produced via four doping schemes were examined: Ba 4 Bi(Pb, Tl) 3 O 12-δ , Ba 4 -(BiPb) 3 TlO 12-δ , Ba 4 (Bi,Tl) 2 Pb 2 O 12-δ , and Ba 4 Bi x Pb 4-2x Tl x O 12-δ . For the parent compound a value of δ = 0.91 was observed, indicating that approximately 1/4 oxygen atom was missing per cubic subsection of the unit cell. For all samples, the symmetry of the parent compound changed from orthorhombic to tetragonal as the system moved away from the ideal composition. This was usually accompanied by the loss of superconductivity, which exhibited a maximum T c of 10.5 K for the parent compound Ba 4 BiPb 2 TlO 12-δ . Also reported are high-temperature magnetic susceptibility results, which are used to determine the effect of metal substitution on the density of states at the Fermi level. For each set of variants on the parent composition, the onset of superconductivity was accompanied by a significant decrease in the size of the Pauli paramagnetic signal. 16 refs., 6 figs

  2. Pb-for-Bi substitution for enhancing thermoelectric characteristics of [(Bi,Pb)2Ba2O4+/-ω]0.5CoO2

    Science.gov (United States)

    Sakai, K.; Karppinen, M.; Chen, J. M.; Liu, R. S.; Sugihara, S.; Yamauchi, H.

    2006-06-01

    We report strongly enhanced thermoelectric characteristics for a misfit-layered oxide, [Bi2Ba2O4±ω]0.5CoO2, in a wide temperature range, as achieved through substituting up to 20% of Bi by Pb. The Pb substitution kept the thermal conductivity (κ) unchanged but decreased the electrical resistivity (ρ) and increased the Seebeck coefficient (S) simultaneously, such that a three-fold enhancement in the thermoelectric figure of merit, Z (≡S2/ρκ), was realized. At the same time x-ray absorption near-edge structure data indicated that the valence and spin states of Co are not affected by the Pb-for-Bi substitution.

  3. Comparative study of silicate glasses containing Bi2O3, PbO and BaO: Radiation shielding and optical properties

    International Nuclear Information System (INIS)

    Kirdsiri, K.; Kaewkhao, J.; Chanthima, N.; Limsuwan, P.

    2011-01-01

    Research highlights: → We change Bi 2 O 3 , PbO and BaO concentration in silicate glasses. → The densities of Bi 2 O 3 glasses more than PbO glasses and BaO glasses. → The Um of Bi 2 O 3 glasses and PbO glasses are comparable and more than BaO glasses. → This suggests that Bi 2 O 3 can replace PbO in radiation shielding glasses. - Abstract: The radiation shielding and optical properties of xBi 2 O 3 :(100-x)SiO 2 , xPbO:(100-x)SiO 2 and xBaO:(100-x)SiO 2 glass systems (where 30 ≤ x ≤ 70 is the composition by weight%) have been investigated. Total mass attenuation coefficients (μ m ) of glasses at 662 keV were improved by increasing their Bi 2 O 3 and PbO content, which raised the photoelectric absorption in glass matrices. Raising the BaO content to the same fraction range, however, brought no significant change to μ m . These results indicate that photon is strongly attenuated in Bi 2 O 3 and PbO containing glasses, and but not in BaO containing glass. The results from the optical absorption spectra show an edge that was not sharply defined; clearly indicating the amorphous nature of glass samples. It is observed that the cutoff wavelength for Bi 2 O 3 containing glass was longer than PbO and BaO containing glasses.

  4. Superconducting energy gap of BaPb/sub 1-//sub x/Bi/sub x/O3

    International Nuclear Information System (INIS)

    Schlesinger, Z.; Collins, R.T.; Scott, B.A.; Calise, J.A.

    1988-01-01

    We report the first infrared measurement of the superconducting energy gap of BaPb/sub 1-//sub x/Bi/sub x/O 3 . In our polycrystalline samples with T/sub c/≅9.5 K (x≅0.2) we obtain 2Δ≅3.2kT/sub c/, roughly in agreement with the weak-coupling Bardeen-Cooper-Schrieffer prediction, 2Δ = 3.5kT/sub c/, and with tunneling measurements of the gap. We do not observe any structure above the gap energy associated with strong coupling

  5. Study on borate glass system containing with Bi2O3 and BaO for gamma-rays shielding materials: Comparison with PbO

    International Nuclear Information System (INIS)

    Kaewkhao, J.; Pokaipisit, A.; Limsuwan, P.

    2010-01-01

    In this work, the mass attenuation coefficients and shielding parameters of borate glass matrices containing with Bi 2 O 3 and BaO have been investigated at 662 keV, and compare with PbO in same glass structure. The theoretical values were calculated by WinXCom software and compare with experiential data. The results found that the mass attenuation coefficients were increased with increasing of Bi 2 O 3 , BaO and PbO concentration, due to increase photoelectric absorption of all glass samples. However, Compton scattering gives dominant contribution to the total mass attenuation coefficients for studied glass samples. Moreover the half value layers (HVL) of glass samples were also better than ordinary concretes and commercial window glass. These results reflecting that the Bi-based glass can use replace Pb in radiation shielding glass. In the case of Ba, may be can use at appropriate energy such as X-rays or lower.

  6. Structural studies of five layer Aurivillius oxides: A2Bi4Ti5O18 (A=Ca, Sr, Ba and Pb)

    International Nuclear Information System (INIS)

    Ismunandar; Kamiyama, T.; Hoshikawa, A.; Zhou, Q.; Kennedy, B.J.; Kubota, Y.; Kato, K.

    2004-01-01

    The room temperature structures of the five layer Aurivillius phases A 2 Bi 4 Ti 5 O 18 , (A=Ca, Sr, Ba and Pb) have been refined from powder neutron diffraction data using the Rietveld method. The structures consist of [Bi 2 O 2 ] 2+ layers interleaved with perovskite-like [A 2 Bi 2 Ti 5 O 16 ] 2- blocks. The structures were refined in the orthorhombic space group B2eb (SG. No. 41), Z=4, and the unit cell parameters of the oxides are a=5.4251(2), b=5.4034(1), c=48.486(1); a=5.4650(2), b=5.4625(3), c=48.852(1); a=5.4988(3), b=5.4980(4), c=50.352(1); a=5.4701(2), b=5.4577(2), c=49.643(1) for A=Ca, Sr, Ba and Pb, respectively. The structural features of the compounds were found similar to n=2-4 layers bismuth oxides. The strain caused by mismatch of cell parameter requirements for the [Bi 2 O 2 ] 2+ layers and perovskite-like [A 2 Bi 2 Ti 5 O 16 ] 2- blocks were relieved by tilting of the TiO 6 octahedra. Variable temperature synchrotron X-ray studies for Ca and Pb compounds showed that the orthorhombic structure persisted up to 675 and 475K, respectively. Raman spectra of the compounds are also presented

  7. Carrier doping into a superconducting BaPb0.7Bi0.3O3‑δ epitaxial film using an electric double-layer transistor structure

    Science.gov (United States)

    Komori, S.; Kakeya, I.

    2018-06-01

    Doping evolution of the unconventional superconducting properties in BaBiO3-based compounds has yet to be clarified in detail due to the significant change of the oxygen concentration accompanied by the chemical substitution. We suggest that the carrier concentration of an unconventional superconductor, BaPb0.7Bi0.3O3‑δ , is controllable without inducing chemical or structural changes using an electric double-layer transistor structure. The critical temperature is found to decrease systematically with increasing carrier concentration.

  8. Dielectric and magnetic properties of Ba-, La- and Pb-doped Bi0.8Gd0.1M0.1Fe0.9Ti0.1O3 perovskite ceramics

    Directory of Open Access Journals (Sweden)

    Radheshyam Rai

    2014-04-01

    Full Text Available The multiferroic Bi0.8Gd0.1M0.1Fe0.9Ti0.1O3, (where M = Ba (DB, La (DL and Pb (DP has been synthesized by using solid-state reaction technique. Effects of Ba, La and Pb substitution on the structure, electrical and ferroelectric properties of Bi0.8Gd0.1M0.1Fe0.9Ti0.1O3 samples have been studied by performing X-ray diffraction, dielectric and magnetic measurements. The crystal structures of the ceramic samples have a tetragonal phase. The vibrating sample magnetometer (VSM measurement shows a significant change in the magnetic properties of Ba-doped Bi0.8Gd0.1M0.1Fe0.9Ti0.1O3 as compared to La- and Pb-doped ceramics. It is seen that coercive field (HC and remanent magnetization (MR increases with Ba-doped ceramics but decreases for La- and Pb-doped ceramics.

  9. Investigating the local structure of B-site cations in (1-x)BaTiO3-xBiScO3 and (1-x)PbTiO3-xBiScO3 using X-ray absorption spectroscopy

    Science.gov (United States)

    Blanchard, Peter E. R.; Grosvenor, Andrew P.

    2018-05-01

    The structural properties of (1-x)BaTiO3-xBiScO3 and (1-x)PbTiO3-xBiScO3 were investigated using powder X-ray diffraction and X-ray absorption spectroscopy. Diffraction measurements confirmed that substituting small amounts of BiScO3 into BaTiO3 initially stabilizes a cubic phase at x = 0.2 before impurity phases begin to form at x = 0.5. BiScO3 substitution also resulted in noticeable changes in the local coordination environment of Ti4+. X-ray absorption near-edge spectroscopy (XANES) analysis showed that replacing Ti4+ with Sc3+ results in an increase in the off-centre displacement of Ti4+ cations. Surprisingly, BiScO3 substitution has no effect on the displacement of the Ti4+ cation in the (1-x)PbTiO3-xBiScO3 solid solution.

  10. Study of photon interactions and shielding properties of silicate glasses containing Bi2O3, BaO and PbO in the energy region of 1 keV to 100 GeV

    International Nuclear Information System (INIS)

    Chanthima, N.; Kaewkhao, J.; Limsuwan, P.

    2012-01-01

    Highlights: ► Interaction photon with of silicate glasses containing PbO, BaO and Bi 2 O 3 studied. ► All interactions were changed with energy and composition of glasses. ► Shielding properties of glasses are better than some standard shielding materials. - Abstract: The mass attenuation coefficient (μ/ρ), effective atomic number (Z eff ), effective electron density (N e,eff ) and half-value layer (HVL) of xR m O n :(1 − x)SiO 2 glass system (where R m O n are Bi 2 O 3 , PbO and BaO, with 0.3 ⩽ x ⩽ 0.7 is fraction by weight) have been calculated by theoretical approach using WinXCom program in the energy region from 1 keV to 100 GeV. Also, the HVL of these glass samples has been compared with some standard shielding concretes. The variations of μ/ρ, Z eff , N e,eff and HVL with energy are shown graphically only for total photon interaction. It has been observed that the value of these parameters has been changed with energy and composition of the silicate glasses. The better shielding properties of glass samples were obtained compared with some standard shielding concretes. These results indicated that glasses in the present study can be used as radiation shielding materials.

  11. Calorimetric investigation of Pb-Bi system

    International Nuclear Information System (INIS)

    Agarwal, Renu; Jat, Ram Avtar; Sen, B.K.

    2008-01-01

    Enthalpy increment of Pb 0.71 Bi 0.29 compound was determined using high temperature Calvet calorimeter. The data was fit into the following polynomial equation. ΔH(T-298.15 K) J/mol = -10384.96 + 39.23 T - 0.014T 2 - 18970/T. By precipitation method, the enthalpy of formation of the compound of composition Pb 0.68 Bi 0.32 at 448 K, from Pb(l) and Bi(l) was determined to be -2450± 50 J/mol and from Pb(s) and Bi(s) at 298.15 K was calculated to be 4047 J/mol. (author)

  12. Evolution with time of 12 metals (V, Cr, Mn, Co, Cu, Zn, Ag, Cd, Ba, Pb, Bi and U) and of lead isotopes in the snows of Coats Land (Antarctica) since the 1830's

    International Nuclear Information System (INIS)

    Planchon, F.

    2001-01-01

    This work shows that it is now possible to get reliable data on the occurrence of numerous heavy metals at ultra low levels in Antarctic snow, by combining ultra clean field sampling and laboratory sub-sampling procedures and the use of ultra sensitive analytical techniques such as ICP-SFMS and TIMS. It has allowed us to determine concentrations of twelve metals (V, Cr, Mn, Co, Cu, Zn, Ag, Cd, Ba, Pb, Bi et U) and lead isotopic composition in the ultra clean series of snow samples collected at Coats Land, in the Atlantic sector of Antarctica. This work presents a 150 years record of metal inputs from natural and anthropogenic sources to Antarctica from the 1830's to the early 1990's. Lead atmospheric pollution begins as early as the end of the 19. century, peaks during the 1970's-1980's and then falls sharply during recent decades. Evolution in lead isotopic abundance shows that Pb inputs to Antarctica reflect a complex blend of contributions originating from the Southern part of South America and Australia. For Cr, Cu, Zn, Ag, Bi and U, concentrations in the snow show significant increases from 1950 to 1980. These enhancements which cannot be explained by variations in natural inputs, illustrate that atmospheric pollution for heavy metals linked with anthropogenic activities in the Southern Hemisphere countries such as for example ferrous and non-ferrous metal mining and smelting is really global. Study of the time period 1920-1990, has allowed us to detail short-term (intra and inter annual) heavy metals concentration's changes. The large short-term variability, observed in Coats Land snow, shows the complex patterns of metal inputs to Antarctica, associated for instance to changes in long-range transport processes from mid-latitude to polar zone and to variability in the different natural sources, such local volcanic activity, sea-salt spray or crustal dust inputs. (author)

  13. Lead activity in Pb-Sb-Bi alloys

    Directory of Open Access Journals (Sweden)

    A. S. Kholkina

    2014-11-01

    Full Text Available The present work is devoted to the study of lead thermodynamic activity in the Pb-Sb-Bi alloys. The method for EMF measurements of the concentration cell: (–Pb|KCl-PbCl2¦¦KCl-PbCl2|Pb-(Sb-Bi(+ was used. The obtained concentration dependences of the galvanic cell EMF are described by linear equations. The lead activity in the ternary liquid-metal alloy demonstrates insignificant negative deviations from the behavior of ideal solutions.

  14. Structural evolution, electrical properties and electric-field-induced changes of (0.8-x)PbTiO{sub 3}-xBiFeO{sub 3}-0.2BaZrO{sub 3} system near the morphotropic phase boundary

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yongxing; Jin, Changqing; Ye, Pin; Xu, Gang [Xi' an Technological University, School of Materials and Chemical Engineering, Xi' an (China); Li, Peng [Northwest Institute For Nonferrous Metal Research, Xi' an (China); Zeng, Yiming [Kunming Institute of Precious Metals, State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals, Kunming (China)

    2017-04-15

    The crystal structures, piezoelectric property, dielectric transition and electric-field-induced changes in the structures and dielectric constant of (0.8-x)PbTiO{sub 3}-xBiFeO{sub 3}-0.2BaZrO{sub 3} (0.3 ≤ x ≤ 0.4) ceramics near the morphotropic phase boundary have been studied. All the ceramics could be indexed on the base of a tetragonal symmetry. The increasing concentration of BiFeO{sub 3} induces a reduction in the c/a ratio, ranged from 1.022 for x = 0.3 to 1.007 for x = 0.4. Accordingly, the piezoelectric coefficient (d{sub 33}) reaches a maximum value at x = 0.34 (d{sub 33}, 138 pC/N). A relaxor-type dielectric anomaly could be found for all the ceramics. The temperature of the maximum dielectric constant (T{sub m}) at 1 MHz and the degree of the diffuseness for the dielectric anomaly (δ) increase with BiFeO{sub 3} concentration, from 544 and 96 K for x = 0.3 to 574 and 154 K for x = 0.4. After poling, the ceramic for x = 0.34 shows an increase in the c/a ratio and an obvious decrease in the dielectric constant. (orig.)

  15. Behavior of 210Pb and 210Bi in soil-rice system and the effects of carrier-Pb

    International Nuclear Information System (INIS)

    Li Shuding

    1993-01-01

    Chemical species of 210 Pb and 210 Bi in soil and rice were investigated using 210 Pb trace experiment. 79%-91% of 210 Pb in the soil was in available fraction. On the contrary, 80%-98% of 210 Bi was bound. The available 210 Pb in the soil was changed slowly into bound fraction, while the bound 210 Bi transformed gradually into available one. Much of 210 Pb and 210 Bi entered into rice were as inorganic free ions. The bound 210 Pb in rice was less than 1% and the bound 210 Bi was around 40%. The different adsorption affinities between 210 Pb and 210 Bi were demonstrated by the different behavior of them. The effect of carrier-Pb on adsorption of 210 Pb and 210 Bi was also discussed

  16. Single phase in Ba-dopped Bi-based high-T/sub c/ compound

    International Nuclear Information System (INIS)

    Rehman, M.A.; Maqsood, A.

    2001-01-01

    Ba-doped, Bi-based, high-Tc superconductor was prepared by a solid state reaction method. The nominal composition used was Bi/sub 1.6/Pb/sub 0.4/Sr/sub 1.6/Ba/sub 0.4/Ca/sub 2/Cu/sub 3/O/sub y/. The samples were characterized by dc electrical resistivity and ac magnetic susceptibility both as a function of temperature (T). Room temperature x-ray diffraction studies were also done. Binder chemicals do affect the properties of the samples and it was observed that samples prepared with polyvinyl alcohol binder chemical showed good reproducible results. All the Above measurements showed that in the compound Bi/sub 1.6/Pb/sub 0.4/Ca/sub 2/Cu/sub 3/O/sub y/ there exists a single high-T/sub c/ phase with T/sub c.0≅/109 plus minus 1K. It behaves like an ideal metal before the superconducting transition in ρ-T plot and the Mathiessen's rule could be fitted. The ac susceptibility measurements support the observations of electrical resistivity. The lattice constants of the material are a=5.416(7) degree A, b=5.455(6) degree A, and c=37.26(8) degree A. The c-axis lattice constant slightly increased with Ba-doping. This fact indicated that Ba was probably incorporated into the Sr site of the crystal structure. Large sized samples (Diameter '28mm and length' 11mm) are under investigation for thermal transport properties by transient Plane Source (TPS) method. (author)

  17. Three new chalcohalides, Ba4Ge2PbS8Br2, Ba4Ge2PbSe8Br2 and Ba4Ge2SnS8Br2: Syntheses, crystal structures, band gaps, and electronic structures

    International Nuclear Information System (INIS)

    Lin, Zuohong; Feng, Kai; Tu, Heng; Kang, Lei; Lin, Zheshuai; Yao, Jiyong; Wu, Yicheng

    2014-01-01

    Highlights: • Three new chalcohalides: Ba 4 Ge 2 PbS 8 Br 2 , Ba 4 Ge 2 PbSe 8 Br 2 and Ba 4 Ge 2 SnS 8 Br 2 have been synthesized. • The MQ 5 Br octahedra and GeQ 4 tetrahedra form a three-dimensional framework with Ba 2+ in the channels. • Band Gaps and electronic structures of the three compounds were studied. - Abstract: Single crystals of three new chalcohalides: Ba 4 Ge 2 PbS 8 Br 2 , Ba 4 Ge 2 PbSe 8 Br 2 and Ba 4 Ge 2 SnS 8 Br 2 have been synthesized for the first time. These isostructural compounds crystallize in the orthorhombic space group Pnma. In the structure, the tetra-valent Ge atom is tetrahedrally coordinated with four Q (Q = S, Se) atoms, while the bi-valent M atom (M = Pb, Sn) is coordinated with an obviously distorted octahedron of five Q (Q = S, Se) atoms and one Br atom, showing the stereochemical activity of the ns 2 lone pair electron. The MQ 5 Br (M = Sn, Pb; Q = S, Se) distorted octahedra and the GeQ 4 (Q = S, Se) tetrahedra are connected to each other to form a three-dimensional framework with channels occupied by Ba 2+ cations. Based on UV–vis–NIR spectroscopy measurements and the electronic structure calculations, Ba 4 Ge 2 PbS 8 Br 2 , Ba 4 Ge 2 PbSe 8 Br 2 and Ba 4 Ge 2 SnS 8 Br 2 have indirect band gaps of 2.054, 1.952, and 2.066 eV respectively, which are mainly determined by the orbitals from the Ge, M and Q atoms (M = Pb, Sn; Q = S, Se)

  18. A review of Pb-Sb(As-S, Cu(Ag-Fe(Zn-Sb(As-S, Ag(Pb-Bi(Sb-S and Pb-Bi-S(Te sulfosalt systems from the Boranja orefield, West Serbia

    Directory of Open Access Journals (Sweden)

    Radosavljević Slobodan A.

    2016-01-01

    Full Text Available Recent mineralogical, chemical, physical, and crystallographic investigations of the Boranja orefield showed very complex mineral associations and assemblages where sulfosalts have significant role. The sulfosalts of the Boranja orefield can be divided in four main groups: (i Pb-Sb(As-S system with ±Fe and ±Cu; (ii Cu(Ag-Fe(Zn-Sb(As-S system; (iii Ag(Pb-Bi(Sb-S; (iv and Pb-Bi-S(Te system. Spatially, these sulfosalts are widely spread, however, they are the most abundant in the following polymetallic deposits and ore zones: Cu(Bi-FeS Kram-Mlakva; Pb(Ag-Zn-FeS2 Veliki Majdan (Kolarica-Centralni revir-Kojići; Sb-Zn-Pb-As Rujevac; and Pb-Zn-FeS2-BaSO4 Bobija. The multi stage formation of minerals, from skarnhydrothermal to complex hydrothermal with various stages and sub-stages has been determined. All hydrothermal stages and sub-stages of various polymetallic deposits and ore zones within the Boranja orefield are followed by a variety of sulfosalts. [Projekat Ministarstva nauke Republike Srbije, br. OI-176016: Magmatism and geodynamics of the Balkan Peninsula from Mesozoic to present day: Significance for the formation of metallic and non-metallic mineral deposits

  19. Ultrasonic investigations on polonides of Ba, Ca, and Pb

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Devraj; Bhalla, Vyoma [Amity School of Engineering and Technology, New Delhi (India). Dept. of Applied Physics; Bala, Jyoti [Amity School of Engineering and Technology, New Delhi (India). Dept. of Applied Physics; Guru Gobind Singh Indraprastha Univ., New Delhi (India). USICT; Wadhwa, Shikha [Amity Univ., Noida (India). Amity Inst. of Nanotechnology

    2017-07-01

    The temperature-dependent mechanical and ultrasonic properties of barium, calcium, and lead polonides (BaPo, CaPo, and PbPo) were investigated in the temperature range 100-300 K. The second- and third-order elastic constants (SOECs and TOECs) were computed using Coulomb and Born-Mayer potential and these in turn have been used to estimate other secondary elastic properties such as strength, anisotropy, microhardness, etc. The theoretical approach followed the prediction that BaPo, CaPo, and PbPo are brittle in nature. PbPo is found to be the hardest amongst the chosen compounds. Further the SOECs and TOECs are applied to determine ultrasonic velocities, Debye temperature, and acoustic coupling constants along left angle 100 right angle, left angle 110 right angle, and left angle 111 right angle orientations at room temperature. Additionally thermal conductivity has been computed using Morelli and Slack's approach along different crystallographic directions at room temperature. Finally ultrasonic attenuation due to phonon-phonon interaction and thermoelastic relaxation mechanisms has been computed for BaPo, CaPo, and PbPo. The behaviour of these compounds is similar to that of semi-metals with thermal relaxation time of the order 10{sup -11} s. The present computation study is reasonably in agreement with the available theoretical data for the similar type of materials.

  20. Ultrasonic Investigations on Polonides of Ba, Ca, and Pb

    Science.gov (United States)

    Singh, Devraj; Bhalla, Vyoma; Bala, Jyoti; Wadhwa, Shikha

    2017-10-01

    The temperature-dependent mechanical and ultrasonic properties of barium, calcium, and lead polonides (BaPo, CaPo, and PbPo) were investigated in the temperature range 100-300 K. The second- and third-order elastic constants (SOECs and TOECs) were computed using Coulomb and Born-Mayer potential and these in turn have been used to estimate other secondary elastic properties such as strength, anisotropy, microhardness, etc. The theoretical approach followed the prediction that BaPo, CaPo, and PbPo are brittle in nature. PbPo is found to be the hardest amongst the chosen compounds. Further the SOECs and TOECs are applied to determine ultrasonic velocities, Debye temperature, and acoustic coupling constants along , , and orientations at room temperature. Additionally thermal conductivity has been computed using Morelli and Slack's approach along different crystallographic directions at room temperature. Finally ultrasonic attenuation due to phonon-phonon interaction and thermoelastic relaxation mechanisms has been computed for BaPo, CaPo, and PbPo. The behaviour of these compounds is similar to that of semi-metals with thermal relaxation time of the order 10-11 s. The present computation study is reasonably in agreement with the available theoretical data for the similar type of materials.

  1. Liquid Li-Pb-Bi, a new tritium breeder

    International Nuclear Information System (INIS)

    Rogers, A.G.; Benedict, B.L.; Clemmer, R.G.

    1981-01-01

    In light of their potential utility as tritium breeder-blanket materials, a study was conducted to identify and characterize low-melting phases in the lithium-lead-bismuth system. It is found that a low-melting ternary phase field did in fact exist, e.g., compositions with less than or equal to 20 atom percent lithium and Pb/Bi = 0.773 melted at or below 140 0 C. In addition, the qualitative reactivity of Li-Bi-Pb alloys with water was tested, and although minimal evidence of exothermic chemical reaction was observed, a physical vapor explosion did occur in one of the tests

  2. On the existence of PbBi3PO8

    International Nuclear Information System (INIS)

    Steinfink, H.; Dass, R.I.; Lynch, V.; Harlow, R.L.; Lee, P.L.

    2005-01-01

    The title compound crystallizes in the tetragonal system, a = 11.733(2) A, c = 15.587(3) A, I4 mm, Z = 10. Data were collected at the Argonne National Laboratory synchrotron source at λ = 0.15359 A. Least squares refinement on F 2 converged to R1 = 0.039. The oxygen coordination polyhedra around Bi and Pb display the distortions typical of 6s 2 lone-pair atoms. One Bi is disordered. Bi-O bonds vary from 2.08(2) to 2.96(1) A. One Pb is in cubic coordination to oxygen and the second Pb is bonded to six oxygen atoms that form a rectangular pyramid and a seventh oxygen is off one of the rectangular faces of the pyramid. Pb-O bonds vary from 2.303(6) to 2.804(17) A. Of the two crystallographically independent P one is in a single tetrahedral coordination while the second is at the center of two disordered tetrahedra. Units of OM 4 tetrahedra, M = Bi/Pb, articulate into a three-dimensional framework by corner and edge sharing that is strengthened by corner sharing with PO 4 moieties

  3. Position annihilation study on the (Bi,Pb)-Sr-Ca-Cu-(O,F) superconductor

    International Nuclear Information System (INIS)

    Wang Xiaogang; Gao Xiaohui; Wang Ruidan; Hu Pingya

    1993-01-01

    In this note, we report the results of positron lifetime measurements in heat-treated (Bi, Pb)-Sr-Ca-Cu-(O, F), and discuss the possible location of the doped fluorine in the (Bi, Pb)-system superconductors. (orig.)

  4. [sup 205]Bi/[sup 206]Bi cyclotron production from Pb-isotopes for absorption studies in humans

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, R.; Dresow, B.; Heinrich, H.C. (Universitaetskrankenhaus Eppendorf, Hamburg (Germany). Abt. Medizinische Biochemie); Wendel, J.; Bechtold, V. (Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Kernphysik)

    1993-12-01

    Pb(p,xn) thick target excitation functions were measured in the energy range 10-38 MeV in order to optimize the production of isotopically pure radiobismuth from [sup nat]Pb, [sup 206]Pb, and [sup 207]Pb. Additionally, the decay of Po-isotopes from deuteron irradiation of natural bismuth ([sup 209]Bi) was exploited for radiobismuth production. [sup 205]Bi was produced from [sup 206]Pb at 20 MeV with only 2% of [sup 206]Bi at 4 weeks post irradiation. Bismuth compounds as used in the treatment of peptic ulcer were labeled with [sup 205]Bi for absorption studies in animals and subjects. (Author).

  5. Thermoelectric transport properties of BaBiTe{sub 3}-based materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yiming; Zhao, Li-Dong, E-mail: zhaolidong@buaa.edu.cn

    2017-05-15

    BaBiTe{sub 3}, a material with low thermal conductivity, is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. We choose two types of dopants, K and La, trying to optimize its electrical transport properties. The minority carriers, which harm the Seebeck coefficient in this system, are suppressed by La doping. With the increase of both electrical conductivity and Seebeck coefficient, the power factor of 3% La doped BaBiTe{sub 3} reaches 3.7 μW cm{sup −1} K{sup −2} which increased by 40% from undoped BaBiTe{sub 3}. Besides high power factor, the thermal conductivity is also reduced in it. Eventually, a high ZT value, 0.25 at 473 K, for n-type BaBiTe{sub 3} is achieved in 3% La doped BaBiTe{sub 3}. - Graphical abstract: BaBiTe{sub 3} possesses a low thermal conductivity. However, it is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. A high ZT value of 0.25 at 473 K for n-type BaBiTe{sub 3} can be achieved through optimizing electrical transport properties via La doping. - Highlights: • BaBiTe{sub 3} is an analogue of these promising thermoelectric materials: such as CsBi{sub 4}Te{sub 6} and K{sub 2}Bi{sub 8}Se{sub 13}, etc. • BaBiTe{sub 3} possesses a low thermal conductivity. • La is an effective dopant to enhance electrical transport properties. • A high ZT value of 0.25 at 473 K can be achieved in n-type La-doped BaBiTe{sub 3}.

  6. modified BiFeO3–BaTiO3

    Indian Academy of Sciences (India)

    based perovskite structures lead- free BiFeO3–BaTiO3 solid solutions are popularly studied due to the high Curie temperature (TC). It was reported that the BiFeO3–BaTiO3 system possessed high piezoelectric. ∗. Author for correspondence ...

  7. Theoretical basis of oxygen pressure control in liquid Pb-Bi using YSZ

    International Nuclear Information System (INIS)

    Jung, S. H.; Hwang, I. S.; Park, B. K.

    2002-01-01

    To develop a liquid Pb-Bi cooled reactor, it is necessary to solve the structural material corrosion problem caused by Pb-Bi. This experiment examine the fundamental behaviors to practically test the oxide film formation on the surface of structural material known as solution of corrosion inhibition in liquid Pb-Bi. The corrosion inhibition through oxide film formation is to prevent metals from dissolving into liquid Pb-Bi though not forming coolants slug resulted from oxidation. In this paper, we examined the oxygen pressure controllability using YSZ in cover gas, and theoretically derived the relationship between oxygen cover gas pressure and dissolved oxygen in liquid Pb-Bi

  8. Search for negative U in the Ba1-xKxBi1-yPbyO3 system using constrained density-functional theory

    International Nuclear Information System (INIS)

    Vielsack, G.; Weber, W.

    1996-01-01

    Calculations using constrained density-functional theory have been carried out for the Ba 1-x K x Bi 1-y Pb y O 3 system, using a full-potential linearized-augmented-plane-wave method and employing fcc supercell geometries with two formula units. The results have been mapped onto Hubbard-type models in order to extract values of interaction parameters U at the Bi sites. Two different mapping procedures have been utilized. The first one is the standard method, based on the comparison of total-energy curvatures. The second method, proposed in the present work, relies on the analysis of single particle energies and yields much smaller numerical errors. For BaBiO 3 interaction parameters are obtained for the following models: (i) s and p orbitals at Bi and p orbitals at O sites. Here, U s =3.1±0.4 eV, U sp =1.4±0.2 eV, U p =2.2±0.4 eV are found, (ii) s(Bi) and p(O) orbitals, yielding U s =1.9±0.7 eV, and (iii) an effective one-band model, leading to U s =0.6±0.4 eV. Further studies have been performed for breathing distorted BaBiO 3 and for various Ba 1-x K x Bi 1-y Pb y O 3 alloys using virtual crystal approximations. The resulting U values are somewhat larger than for pure BaBiO 3 . Thus, in all cases, the values of Bi U parameters are found to be positive. There is no indication of a negative U of electronic origin. copyright 1996 The American Physical Society

  9. Sorption of radionuclides from Pb-Bi melt. Report 1

    International Nuclear Information System (INIS)

    Konovalov, Eh.E.; Il'icheva, N.S.; Trifonova, O.E.

    2015-01-01

    Results of laboratory investigations of sorption and interfacial distribution of 54 Mn, 59 Fe, 60 Co, 106 Ru, 125 Sb, 137 Cs, 144 Ce, 154,155 Eu and 235,238 U radionuclides in the system Pb-Bi melt - steel surface are analyzed. It is shown that 106 Ru and 125 Sb are concentrated in Pb-Bi melt and other radionuclides with higher oxygen affinity are sorbed on oxide deposits on structural materials. Temperature dependences of sorption efficiency of radionuclides are studied. It is shown that there is sharp increase of this value for all radionuclides near the temperature range 350-400 deg C. Recommendations are given on the use of 106 Ru and 125 Sb as a reference for fuel element rupture detection system with radiometric monitoring of coolant melt samples and 137 Cs, 134 Cs, 134m Cs with radiometric monitoring of sorbing samples [ru

  10. Doping of (Bi,Pb)-2223 with metal oxides

    International Nuclear Information System (INIS)

    Goehring, D.; Vogt, M.; Wischert, W.; Kemmler-Sack, S.

    1997-01-01

    The effect of doping on formation, superconductivity and pinning forces of (Bi,Pb)-2223 was studied for several dopants. They can be subdivided into promoters (Cu, Mn at low doping level of x=0.1 and Rh) and inhibitors (Mg, Al, Sn, Co, Y, Pd and high substitution levels of Mn and Ni) of the transformation of the precursor material into (Bi,Pb)-2223. According to X-ray diffraction (XRD) studies the incorporation of the dopant into the 2223 lattice is restricted to a very low doping level. Higher dopant concentrations are accompanied by a segregation of secondary phases. These segregations are not effective in the process of creating flux pinning centres. A depression of T c is observed for 2223 materials with the dopants Co, Ni and Pd. (orig.)

  11. Synthesis and electrical properties of BaBiO3 and high resistivity BaTiO3–BaBiO3 ceramics

    Directory of Open Access Journals (Sweden)

    Nitish Kumar

    2016-12-01

    Full Text Available Ceramics of the composition BaBiO3 (BB were sintered in oxygen to obtain a single phase with monoclinic I2/m symmetry as suggested by high-resolution X-ray diffraction. X-ray photoelectron spectroscopy confirmed the presence of bismuth in two valence states — 3+ and 5+. Optical spectroscopy showed presence of a direct bandgap at ∼ 2.2eV and a possible indirect bandgap at ∼ 0.9eV. This combined with determination of the activation energy for conduction of 0.25eV, as obtained from ac impedance spectroscopy, suggested that a polaron-mediated conduction mechanism was prevalent in BB. The BB ceramics were crushed, mixed with BaTiO3 (BT, and sintered to obtain BT–BB solid solutions. All the ceramics had tetragonal symmetry and exhibited a normal ferroelectric-like dielectric response. Using ac impedance and optical spectroscopy, it was shown that resistivity values of BT–BB were orders of magnitude higher than BT or BB alone, indicating a change in the fundamental defect equilibrium conditions. A shift in the site occupancy of Bi to the A-site is proposed to be the mechanism for the increased electrical resistivity.

  12. Bioaccessibility of Ba, Cu, Pb, and Zn in urban garden and orchard soils

    International Nuclear Information System (INIS)

    Cai, Meifang; McBride, Murray B.; Li, Kaiming

    2016-01-01

    Exposure of young children to toxic metals in urban environments is largely due to soil and dust ingestion. Soil particle size distribution and concentrations of toxic metals in different particle sizes are important risk factors in addition to bioaccessibility of these metals in the particles. Analysis of particle size distribution and metals concentrations for 13 soils, 12 sampled from urban gardens and 1 from orchard found that fine particles (<105 μm) comprised from 22 to 66% by weight of the tested soils, with Ba, Cu, Pb and Zn generally at higher concentrations in the finer particles. However, metal bioaccessibility was generally lower in finer particles, a trend most pronounced for Ba and Pb. Gastric was higher than gastrointestinal bioaccessibility for all metals except Cu. The lower bioaccessibility of Pb in urban garden soils compared to orchard soil is attributable to the higher organic matter content of the garden soils. - Highlights: • The bioaccessibility of metals in urban garden and orchard soils was measured. • Ba, Cu, Pb, Zn were concentrated in fine particles of the soils. • Bioaccessibilities of Ba and Pb were generally lower in fine particles of soils. • Pb bioaccessibility was generally lower in soils with higher organic matter content. • Pb bioaccessibility was lower in urban garden soils than in an orchard soil. - Pb and other trace metals (Ba, Cu, Zn) were concentrated in fine particles of urban and orchard soils, but the bioaccessibility of Ba and Pb was generally lower in finer particles.

  13. Fabrication of Ba-K-Bi-O thick film artefacts with improved critical currents

    International Nuclear Information System (INIS)

    Moore, J.C.; Salter, C.J.; Jenkins, R.J.; Grovenor, C.R.M.; Jones, H.

    1993-01-01

    The Ba-K-Bi-O system has a maximum T c of around 30K for a composition of Ba 0.6 K 0.4 BiO 3 . Fabrication of good quality single phase samples is extremely difficult and requires careful control of the fabrication conditions. Successful synthesis procedures for Ba-K-Bi-O powder and melt cast material which allow some control of the potassium content of the product were established by Hinks et al. The process is based on a melt and sinter step in an inert atmosphere which creates oxygen vacancies and allows potassium to enter the lattice. The oxygen vacancies are then filled by a subsequent oxygen anneal to obtain superconductivity. Ba-K-Bi-O is, therefore, metastable and consequently difficult to synthesise. There have been few reports of transport measurements and even fewer reports of transport critical currents for bulk material. It is often accepted that Ba-K-Bi-O has an intrinsically low critical current, and extremely poor critical current densities of 0.05 Acm -2 have been quoted for melt cast material. It has been suggested that the presence of weak links is the cause. However, there has been little research into the relationship between process conditions and superconducting properties for melt processed Ba-K-Bi-O to confirm this. (orig.)

  14. Large linear magnetoresistance in a new Dirac material BaMnBi2

    Science.gov (United States)

    Wang, Yi-Yan; Yu, Qiao-He; Xia, Tian-Long

    2016-10-01

    Dirac semimetal is a class of materials that host Dirac fermions as emergent quasi-particles. Dirac cone-type band structure can bring interesting properties such as quantum linear magnetoresistance and large mobility in the materials. In this paper, we report the synthesis of high quality single crystals of BaMnBi2 and investigate the transport properties of the samples. BaMnBi2 is a metal with an antiferromagnetic transition at T N = 288 K. The temperature dependence of magnetization displays different behavior from CaMnBi2 and SrMnBi2, which suggests the possible different magnetic structure of BaMnBi2. The Hall data reveals electron-type carriers and a mobility μ(5 K) = 1500 cm2/V·s. Angle-dependent magnetoresistance reveals the quasi-two-dimensional (2D) Fermi surface in BaMnBi2. A crossover from semiclassical MR ˜ H 2 dependence in low field to MR ˜ H dependence in high field, which is attributed to the quantum limit of Dirac fermions, has been observed in magnetoresistance. Our results indicate the existence of Dirac fermions in BaMnBi2. Project supported by the National Natural Science Foundation of China (Grant No. 11574391), the Fundamental Research Funds for the Central Universities, and the Research Funds of Renmin University of China (Grant No. 14XNLQ07).

  15. Large linear magnetoresistance in a new Dirac material BaMnBi2

    International Nuclear Information System (INIS)

    Wang Yi-Yan; Yu Qiao-He; Xia Tian-Long

    2016-01-01

    Dirac semimetal is a class of materials that host Dirac fermions as emergent quasi-particles. Dirac cone-type band structure can bring interesting properties such as quantum linear magnetoresistance and large mobility in the materials. In this paper, we report the synthesis of high quality single crystals of BaMnBi 2 and investigate the transport properties of the samples. BaMnBi 2 is a metal with an antiferromagnetic transition at T N = 288 K. The temperature dependence of magnetization displays different behavior from CaMnBi 2 and SrMnBi 2 , which suggests the possible different magnetic structure of BaMnBi 2 . The Hall data reveals electron-type carriers and a mobility μ (5 K) = 1500 cm 2 /V·s. Angle-dependent magnetoresistance reveals the quasi-two-dimensional (2D) Fermi surface in BaMnBi 2 . A crossover from semiclassical MR ∼ H 2 dependence in low field to MR ∼ H dependence in high field, which is attributed to the quantum limit of Dirac fermions, has been observed in magnetoresistance. Our results indicate the existence of Dirac fermions in BaMnBi 2 . (rapid communication)

  16. CFD Simulations of Pb-Bi Two-Phase Flow

    International Nuclear Information System (INIS)

    Dostal, Vaclav; Zelezny, Vaclav; Zacha, Pavel

    2008-01-01

    In a Pb-Bi cooled direct contact steam generation fast reactor water is injected directly above the core, the produced steam is separated at the top and is send to the turbine. Neither the direct contact phenomenon nor the two-phase flow simulations in CFD have been thoroughly described yet. A first attempt in simulating such two-phase flow in 2D using the CFD code Fluent is presented in this paper. The volume of fluid explicit model was used. Other important simulation parameters were: pressure velocity relation PISO, discretization scheme body force weighted for pressure, second order upwind for momentum and CISCAM for void fraction. Boundary conditions were mass flow inlet (Pb-Bi 0 kg/s and steam 0.07 kg/s) and pressure outlet. The effect of mesh size (0.5 mm and 0.2 mm cells) was investigated as well as the effect of the turbulent model. It was found that using a fine mesh is very important in order to achieve larger bubbles and the turbulent model (k-ε realizable) is necessary to properly model the slug flow. The fine mesh and unsteady conditions resulted in computationally intense problem. This may pose difficulties in 3D simulations of the real experiments. (authors)

  17. Structural study, photoluminescence, and photocatalytic activity of semiconducting BaZrO{sub 3}:Bi nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Borja-Urby, R. [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A.C., Leon, Gto 37150 (Mexico); Diaz-Torres, L.A., E-mail: ditlacio@cio.mx [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A.C., Leon, Gto 37150 (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro 76000 (Mexico); Moctezuma, E. [Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, Av. Manuel Nava 6, San Luis Potosi, S.L.P., Mexico 78290 (Mexico); Vega, M. [Centro de Geociencias-UNAM, A.P. 1-1010, Queretaro 76000 (Mexico); Angeles-Chavez, C. [Instituto Mexicano del Petroleo, Ciudad de Mexico, D.F. 07730 (Mexico)

    2011-10-25

    Wide band gap nanocrystalline bismuth doped barium zirconate is synthesized by a facile hydrothermal method at 100 deg. C. The obtained cubic perovskites are characterized by powder X-ray diffraction (XRD), UV-VIS diffuse reflectance spectroscopy, photoluminescence (PL) spectroscopy, and photocatalytic activity. The estimated band gap in the 2.4-4.9 eV range, depending on Bi concentration, suggests nanocrystalline BaZrO{sub 3}:Bi as a useful visible-light activated photocatalyst under excitation wavelengths <800 nm. Displacement of main XRD pattern peaks suggest that bismuth ion mostly substitutes into Zr{sup 4+} sites within the BaZrO{sub 3} host lattice. It is found that BaZrO{sub 3}:Bi decomposes methylene blue (MB) under both UV and visible light irradiation. The photocatalyst efficiency depends strongly on Bi content and induced defects.

  18. Ferroelectric BaPbO3/PbZr0.53Ti0.47/BaPbO3 heterostructures

    International Nuclear Information System (INIS)

    Liang Chunsheng; Wu Jennming; Chang Mingchu

    2002-01-01

    BaPbO 3 (BPO)/PbZr 0.53 Ti 0.47 (PZT)/BPO heterostructures were fabricated by combining the sol-gel and rf-magnetron sputtering techniques. Experimental results indicate that the BPO bottom electrodes effectively prevent the formation of the rosette structure of PZT, producing smooth surfaces. Additionally, ferroelectric, fatigue, and leakage current properties were markedly improved when both the top and the bottom electrodes were changed from Pt to BPO. These improvements are due to a superior electrode/ferroelectric interface. BPO is better than Pt and other oxide electrodes for use in PZT ferroelectric capacitors due to its remarkably improved properties and quite low growth temperature

  19. Perovskite BaBiO3 Transformed Layered BaBiO2.5 Crystals Featuring Unusual Chemical Bonding and Luminescence.

    Science.gov (United States)

    Li, Hong; Zhao, Qing; Liu, Bo-Mei; Zhang, Jun-Ying; Li, Zhi-Yong; Guo, Shao-Qiang; Ma, Ju-Ping; Kuroiwa, Yoshihiro; Moriyoshi, Chikako; Zheng, Li-Rong; Sun, Hong-Tao

    2018-04-14

    Engineering oxygen coordination environments of cations in oxides has received intense interest thanks to the opportunities for the discovery of novel oxides with unusual properties. Here we present the successful synthesis of stoichiometric layered BaBiO2.5 enabled by a non-topotactic phase transformation of perovskite BaBiO3. By analysing the synchrotron X-ray diffraction data using the maximum entropy method/Rietveld technique, we find that Bi forms unusual chemical bondings with four oxygen atoms, featuring one ionic bonding and three covalent bondings that results in an asymmetric coordination geometry. A broad range of photophysical characterizations reveal that this peculiar structure shows near-infrared luminescence differing from conventional Bi-bearing systems. Experimental and theoretical results lead us to propose the excitonic nature of luminescence. Our work highlights that synthesizing materials with uncommon Bi-O bonding and Bi coordination geometry provides a pathway to the discovery of systems with new functionalities. We envisage that this work could inspire interest for the exploration of a range of materials containing heavier p-block elements, offering prospects for the finding of systems with unusual properties. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Characterization of BaBi2Ta2O9 prepared through amorphous precursor

    International Nuclear Information System (INIS)

    Maczka, M.; Kepinski, L.; Hermanowicz, K.; Dacko, S.; Czapla, Z.; Hanuza, J.

    2011-01-01

    Research highlights: → Formation of Bi-layered BaBi 2 Ta 2 O 9 proceeds via an intermediate fluorite phase. → Mechanochemical activation lowers the synthesis temperature by 150-200 deg. C. → The lateral size of the synthesized plate-like crystallites is about 100-200 nm. → Properties of the synthesized crystallites are different from the bulk material. - Abstract: Formation of ferroelectric BaBi 2 Ta 2 O 9 by annealing of an amorphous precursor prepared by high energy milling in ball mill has been studied by X-ray, scanning electron microscopy (SEM), Raman, infrared spectroscopy (IR), diffuse reflectivity and dielectric measurements. Our results show that formation of Bi-layered BaBi 2 Ta 2 O 9 proceeds via an intermediate fluorite phase. Mechanochemical activation allows obtaining BaBi 2 Ta 2 O 9 at short time and much lower temperatures than those required in a conventional solid state reaction. The lateral size of the plate-like crystallites is about 100-200 nm and properties of the synthesized particles are different compared to the bulk material.

  1. The ‘sub’ metallide oxide hydrides Sr{sub 21}Si{sub 2}O{sub 5}H{sub 12+x} and Ba{sub 21}M{sub 2}O{sub 5}H{sub 12+x} (M = Zn, Cd, Hg, In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi)

    Energy Technology Data Exchange (ETDEWEB)

    Jehle, Michael; Hoffmann, Anke [Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, D-79104 Freiburg (Germany); Kohlmann, Holger [Institut für Anorganische Chemie, Universität Leipzig, Johannisallee 29, D-04103 Leipzig (Germany); Scherer, Harald [Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, D-79104 Freiburg (Germany); Röhr, Caroline, E-mail: caroline@ruby.chemie.uni-freiburg.de [Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, D-79104 Freiburg (Germany)

    2015-02-25

    Highlights: • The sub metallide oxide hydrides (Sr/Ba){sub 21}M{sub 2}O{sub 5}H{sub 12+x} were prepared for 14 M elements. • M covers a wide range of elements, from the Zn group to the pentels. • The ionic partial structure contains isolated M anions and suboxide clusters [O{sub 5}A{sub 18}]. • The H-content was determined by neutron diffraction and {sup 1}H/{sup 2}D MAS-NMR spectroscopy. • Band structure calculations support the H/D content and distribution. - Abstract: The title compounds sporting a great variety of anions M of different formal charges have been synthesized from melts of the composition A:M:O:H/D = 21:2:5:24, using BaH{sub 2}/SrH{sub 2} as hydrogen sources. All phases were characterized by means of single crystal X-ray data [cubic, space group Fd3{sup ¯}m; Sr{sub 21}Si{sub 2}O{sub 5}H{sub 12+x}: a = 1911.90(1) pm, R1 = 0.0201; for the barium phases with Zn (a = 2041.7(3) pm, R1 = 0.077), Cd (a = 2063.3(1) pm, R1 = 0.051), Hg (a = 2050.7(1) pm, R1 = 0.059), In (a = 2060.7(1) pm, R1 = 0.101), Tl (a = 2068.1(10) pm, R1 = 0.0485), Si (a = 2033.6(1) pm, R1 = 0.045), Ge (a = 2035.6(1) pm, R1 = 0.037), Sn (a = 2053.2(2) pm, R1 = 0.054), Pb (a = 2059.7(1) pm, R1 = 0.056), As (a = 2023.0(3) pm, R1 = 0.087), Sb (a = 2041.9(1) pm, R1 = 0.067) and Bi (a = 2045.9(1) pm, R1 = 0.075)]. Neutron powder diffraction data collected for the Ba silicide (both H and D compound) were refined by the Rietveld method (a = 2037.0(1), R{sub p} = 0.0173; wR{sub p} = 0.0304, R(F{sup 2}) = 0.086). The statistically occupied (H/D)(1) site 96g, which corresponds to the carbon position inSr{sub 21}Si{sub 2}O{sub 5}C{sub 6}, together with two further sparsely occupied sites (H/D)(2,3), yields the overall composition Ba{sub 21}Si{sub 2}O{sub 5}D{sub 14}. The hydrogen content, its chemical character and the distribution among the three H/D positions was evaluated by {sup 1}H/{sup 2}H MAS NMR spectroscopy for the Si, Ge and Sb compound. The crystal structure exhibits two

  2. Synthesis and Dielectric Properties of Ba3NaBiNb10O30 Ceramics

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new niobate Ba3NaBiNb10O30 was synthesized by the solid state reaction.The reaction mixture was characterized by thermogravimetric and differential thermal analysis (TG-DTA),X-ray diffraction and dielectric constant measurements.The results show that Ba3NaBiNb10O30 has an orthorhombic tungsten bronze structure with space group Cmm2 and the unit cell parameters are a=1.7660(1) nm,a=1.7626(1) nm,c=0.78621(6) nm,Z=4.Ba3NaBiNb10O30 undergoes two phase transitions at 200℃ and 400℃,respectively.

  3. Oxygen permeability of perovskite-type BaBi1-xLaxO3-δ

    International Nuclear Information System (INIS)

    Yaremchenko, A.A.; Kharton, V.V.; Viskup, A.P.; Naumovich, E.N.; Samokhval, V.V.

    1998-01-01

    Oxygen permeability, electrical conductivity, and thermal expansion of BaBi 1-x La x O 3-δ (x = 0, 0.2, and 0.4) perovskite-like solid solutions have been found to decrease with lanthanum content. Thermal expansion coefficients of the ceramics are (11.9--12.8) x 10 -6 K -1 . Oxygen transport through the BaBi(La)O 3-δ dense ceramic membranes within the membrane thickness range of 0.6 < d < 1.2 mm has been shown to be limited by both bulk ionic conductivity and surface exchange rate

  4. Superconducting properties of Pb82Bi18 films controlled by ferromagnetic nanowire arrays

    International Nuclear Information System (INIS)

    Ye Zuxin; Lyuksyutov, Igor F; Wu Wenhao; Naugle, Donald G

    2011-01-01

    The superconducting properties of Pb 82 Bi 18 alloy films deposited on ferromagnetic nanowire arrays have been investigated. Ferromagnetic Co or Ni nanowires are first electroplated into the columnar pores of anodic aluminum oxide (AAO) membranes. Superconducting Pb 82 Bi 18 films are then quench condensed onto the polished surface of the AAO membranes filled with magnetic nanowires. A strong dependence of the Pb 82 Bi 18 superconducting properties on the ratio of the superconducting film thickness to the magnetic nanowire diameter and material variety was observed.

  5. Superconducting properties of Pb82Bi18 films controlled by ferromagnetic nanowire arrays

    Science.gov (United States)

    Ye, Zuxin; Lyuksyutov, Igor F.; Wu, Wenhao; Naugle, Donald G.

    2011-02-01

    The superconducting properties of Pb82Bi18 alloy films deposited on ferromagnetic nanowire arrays have been investigated. Ferromagnetic Co or Ni nanowires are first electroplated into the columnar pores of anodic aluminum oxide (AAO) membranes. Superconducting Pb82Bi18 films are then quench condensed onto the polished surface of the AAO membranes filled with magnetic nanowires. A strong dependence of the Pb82Bi18 superconducting properties on the ratio of the superconducting film thickness to the magnetic nanowire diameter and material variety was observed.

  6. Synthesis and characterization of PbO-CdO nanocomposite and its effect on (Bi,Pb)-2223 superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Yahya, Nabil A.A. [Thamar University, Physics Department, Faculty of Education, Thamar (Yemen); Al-Gaashani, R. [Thamar University, Physics Department, Faculty of Education, Thamar (Yemen); Qatar Environment and Energy Research Institute (QEERI), Hamad Bin Khalifa University (HBKU), Doha (Qatar); Abd-Shukor, R. [Universiti Kebangsaan Malaysia, School of Applied Physics, Bangi, Selangor (Malaysia)

    2017-03-15

    A PbO-CdO nanocomposite-added Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} ((Bi,Pb)-2223) superconductor has been prepared. The effect of the PbO-CdO nanocomposite addition on the transport critical current density (J{sub c}) of (Bi,Pb)-2223 superconductor was investigated. The transition temperature (T{sub c-onset}), zero electrical resistance temperature (T{sub c-R=0}), and J{sub c} of the samples were measured by the four-probe method. Phase formation, structure, and microstructure of samples were investigated. The distribution of nanoparticle size was determined. The results indicated that the PbO-CdO-added samples showed larger grain size and an increased volume fraction of high-T{sub c} phase (Bi-2223) compared to the non-added sample. A slight increase in T{sub c-R=0} of x = 0.15 wt% was observed. J{sub c} of the PbO-CdO nanocomposite-added samples was significantly higher than for the non-added sample. That could be explained by the possibility that the PbO-CdO nanocomposite acts as an effective flux pinning center in (Bi,Pb)-2223. At 77 K, J{sub c} of x = 0.15 wt% added sample was more than 20 times larger than J{sub c} of the non-added sample (x = 0 wt%). A combined effect of enhanced flux pinning, increased fraction of high-T{sub c} phase and improved grain size, which led to increase in the J{sub c} of added samples, is discussed. (orig.)

  7. Relaxor behaviour and dielectric properties of BiFeO3 doped Ba ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Ba1−Bi(Ti0.9Zr0.1)1−FeO3 ( = 0–0.075) ceramics are prepared using a conventional solid state reaction method. X-ray diffraction shows the presence of a single phase. Addition of Bi3+ and Fe3+ strongly influences the crystal structure and dielectric properties of the ceramics. The evolution from a ...

  8. Phase transition in vortex system in Bi2212:Pb monocrystal

    CERN Document Server

    Uspenskaya, L S; Rakhmanov, A L

    2002-01-01

    Penetration of the magnetic flux into the (Bi sub 0 sub . sub 8 sub 4 Pb sub 0 sub . sub 1 sub 6) sub 2 sub . sub 2 Sr sub 2 CaCu sub 2 O sub 8 high-temperature superconductor monocrystal is studied thorough the magnetooptical method in the crossed magnetic fields. It is shown that the magnetic flux penetration in the low-temperature areas is anisotropic: it moves primarily along the magnetic field, applied in the sample plane, and this anisotropy grows with the temperature growth. At the temperature of T sub m = 54 +- 2 K there takes place sharp change in the character of the magnetic field penetration into the superconductor, whereby the direction of the flux motion discontinues to be dependent on the direction and value of the magnetic field applied in the sample plane. This effect is interpreted within the frames of representations on the phase transition in the vortex system connected with a sharp decrease in the correlations of the vortex position in the different CuO-planes

  9. Corrosion behavior of materials in a liquid Pb-Bi spallation target

    International Nuclear Information System (INIS)

    Barbier, F.; Balbaud, F.; Deloffre, P.; Terlain, A.

    2001-01-01

    Corrosion results of austenitic and martensitic steels exposed to Pb-Bi liquid alloy (material candidate for the spallation target of ADS) are presented. They show the large influence of parameters such as the oxygen content in Pb-Bi and the Pb-Bi velocity on the corrosion. At low O 2 content (7 10 -8 wt%) in Pb-Bi the steels can suffer from significant dissolution while at high O 2 (1-2 10 -6 wt%) content they can be covered by an oxide layer which protects them from the dissolution. Moreover it is shown that, in aniso-thermal systems, the deposit chemical composition formed in the cold parts can depend on the temperature. (authors)

  10. Effect of Pb and Cr Substitutions on Phase Formation and Excess Conductivity of Bi-2212 Superconductor

    International Nuclear Information System (INIS)

    Khir, F. L. M.; Mohamed, Z.; Yusuf, A. A.; Yusof, M. I. M.; Yahya, A. K.

    2010-01-01

    The influence of Pb and Cr substitutions on the superconducting properties of Bi 2 Sr 2 CaCu 2 O 8 (Bi-2212) superconductors is reported. The samples were prepared from Bi 2-x Pb x Sr 2 Ca 2-y Cr y Cu 3 O 10-δ (x = 0-0.3, y = 0-0.3) starting composition by the solid-state-reaction method. XRD analysis showed formation of pure Bi-2212 for (x = 0, y = 0), (x = 0.3, y = 0.2,) and (x = 0.3, y = 0.2,) starting compositions. Excess conductivity analysis based on Asmalazov-Larkin theory on single-phased Bi2212 samples showed 2D to 3D transition in superconducting fluctuation behavior (SFB) for all the samples. Highest 2D-3D transition temperature, T 2D-3D was observed at Pb and Cr substitutions of x = 0.3, and x = 0.2, respectively.

  11. Natural Radioisotopes of Pb, Bi and Po in the Atmosphere of Coal Burning Area

    Directory of Open Access Journals (Sweden)

    Asnor Azrin Sabuti

    2011-07-01

    Full Text Available This paper is discussing the changes of natural radionuclides 210Pb, 210Bi and 210Po in atmospheric samples (rainwater and solid fallout caused by Sultan Salahuddin Abdul Aziz coal-fired Power Plant (SSAAPP operation. We also describe the seasonal changes of 210Pb, 210Bi and 210Po to the monsoon seasons in Peninsular Malaysia. Bulk atmospheric trap was used to collect atmospheric samples for five months (7 Feb 2007 to 27 July 2007 and placed within the SSAAPP area. The natural radionuclide activity levels in the atmosphere were affected by local meteorological conditions to impact their variance over time. As a result, the natural radionulides were increased from the ambient value in atmospheric particles (solid fallout, which related to coal combustion by-product releases into atmosphere. In contrast, this was giving relatively lower or in the same magnitude from most places of radionuclides in rainwater samples. Degree of changes between 210Pb, 210Bi and 210Po affected by high temperature combustions were found to be different for each nuclide due to their respective volatility. 210Po in rainwater and solid fallout were considerably low during early inter-monsoon period which mainly controlled by the rainfall pattern. On the other hand, 210Pb and 210Bi in solid fallout were recorded higher concentrations which associated to drier conditions and more particulate content in air column during southwest monsoon. The mean activity ratio of 210BiRW/210PbRW and 210PoRW/210PbRW are 0.47 ± 0.04 and 0.52 ± 0.17, respectively. Whereas for 210BiSF/210PbSF and 210PoSF/210PbSF are 0.52 ± 0.05 and 0.71 ± 0.13, respectively. Some results showed high activity ratios, reaching to 1.87 ± 0.08 for 210Bi/210Pb and 4.58 ± 0.55 for 210Po/210Pb, of which due to additional of 210Bi and 210Po excess. These ratios also indicating that 210Pb and 210Bi could potentially come from the same source, compared to 210Po which varied differently, showing evidence it came

  12. Contactless flowrate sensors for Na, PbBi and Pb flows

    International Nuclear Information System (INIS)

    Buchenau, D.; Gerbeth, G.; Priede, J.

    2011-01-01

    Accurate and reliable flow rate measurements are required for various liquid metal systems such as the Na or Lead-flows in fast reactors, the PbBi-flows in transmutation systems, or the flows in liquid metal targets. For liquid metal flows, a contactless measurement is preferable. In this paper we report on the recent development of two types of such flow meters. The former operates by detecting the flow-induced disturbance in the phase distribution of an externally applied AC magnetic field. Such a phase-shift flow meter was developed with an emitting coil at one side of the duct and two sensing coils at the opposite side. The second approach uses a rotatable single cylindrical permanent magnet, which is placed close to the liquid metal duct. The rotation rate of this magnet is proportional to the flow rate. (author)

  13. Technology for cleaning of Pb-Bi adhering to steel (1). Basic tests

    International Nuclear Information System (INIS)

    Saito, Shigeru; Sasa, Toshinobu; Umeno, Makoto; Kurata, Yuji; Kikuchi, Kenji; Futakawa, Masatoshi

    2004-12-01

    The accelerator driven system (ADS) is proposed to transmute minor actinides (MA) in high-level waste from spent fuels of nuclear power reactors. Liquid Pb-Bi alloy is a candidate material for spallation target and coolant of ADS. Pb-Bi cleaning technology is required to reduce radiation exposure during maintenance service and to decontaminate replaced components. In this study, three cleaning methods were tested; silicon oil cleaning at 170degC, mixture of acetic acid and nitric acid cleaning. Specimens were prepared by immersion in melted Pb-Bi. After silicon oil tests, most of Pb-Bi remained on the surface of the specimens. It was found that blushing was needed to remove Pb-Bi effectively. On the other hands, Pb-Bi was easily dissolved and almost removed in the mixed acid and nitric acid. Silicon oil cleaning did not affect on base metals. The surface of base metals was slightly blacked after mixed acid cleaning. F82H base metals were corroded by nitric acid. (author)

  14. A comparative neutronic analysis of KALIMER breeder core using Na or Pb-Bi coolant

    International Nuclear Information System (INIS)

    Yoo, J. W.; Kim, S. J.; Kim, Y. I.

    2000-01-01

    A comparative neutronic study has been conducted on KALIMER breeder core according to the replacement of sodium coolant by Pb-Bi coolant. Since the atomic weight of Pb and Bi is about 9 times heavier than that of Na, the energy loss by neutron colliding with Pb-Bi nucleus will be very small. Therefore, the reactor with Pb-Bi coolant will have a harder neutron spectrum than that with Na coolant. Consequently, the breeding ratio and burnup reactivity swing is expected to be enhanced. In addition, when Pb-Bi coolant is voided, a negative coolant void coefficient can be obtained by the net effects of smaller spectrum hardening and large neutron leakage. As a result, the breeding ratio was increased from 1.18 to 1.23 and burnup reactivity swing was reduced from 631 pcm to 150 pcm. When the coolant in the whole region of active core is voided, the coolant void coefficient was found to be -539 and -264 pcm at BOEC and EOEC, respectively. In the local voided case, the smaller coolant void coefficient was obtained than that of Na coolant. Accordingly, the use of Pb-Bi coolant in KALIMER gives an advantage of higher breeding ratio, smaller burnup reactivity swing and negative coolant void coefficient without any significant degradation of nuclear performance

  15. Correlation between modulation structure and electronic inhomogeneity on Pb-doped Bi-2212 single crystals

    International Nuclear Information System (INIS)

    Sugimoto, A.; Kashiwaya, S.; Eisaki, H.; Yamaguchi, H.; Oka, K.; Kashiwaya, H.; Tsuchiura, H.; Tanaka, Y.

    2005-01-01

    The correlation between nanometer-size electronic states and surface structure is investigated by scanning tunneling microscopy/spectroscopy (STM/S) on Pb-doped Bi 2-x Pb x Sr 2 CaCu2O 8+y (Pb-Bi-2212) single crystals. The advantage of the Pb-Bi-2212 samples is that the modulation structure can be totally or locally suppressed depending on the Pb contents and annealing conditions. The superconducting gap (Δ) distribution on modulated Pb-Bi-2212 samples showed the lack of correlation with modulation structure except a slight reduction of superconducting island size for the b-axis direction. On the other hand, the optimal doped Pb-Bi-2212 (x = 0.6) samples obtained by reduced-annealing showed totally non-modulated structure in topography, however, the spatial distribution of Δ still showed inhomogeneity of which features were quite similar to those of modulated samples. These results suggest that the modulation structure is not the dominant origin of inhomogeneity although it modifies the streaky Δ structure sub-dominantly. From the gap structure variation around the border of narrow gap and broad gap regions, a trend of the coexistence of two separated phases i.e., superconducting phase and pseudogap like phase, is detected

  16. Determining metal ion distributions using resonant scattering at very high-energy K-edges: Bi/Pb in Pb5Bi6Se14

    International Nuclear Information System (INIS)

    Zhang Yuegang; Lee, P.L.; Shastri, S.D.; Shu Deming; Wilkinson, A.P.; Chung Duck-Young; Kanatzidis, M.G.

    2005-01-01

    Powder diffraction data collected at ∝ 86 keV, and just below both the Pb and the Bi K-edges, on an imaging plate detector using synchrotron radiation from the Advanced Photon Source have been used to examine the Pb/Bi distribution over the 11 crystallographically distinct sites in Pb 5 Bi 6 Se 14 [space group P2 1 /m, a=16.0096(2) Aa, b=4.20148(4) Aa, c=21.5689(3) Aa and β=97.537(1) 0 ]. The scattering factors needed for the analyses were determined both by Kramers- Kronig transformation of absorption spectra and by analyses of diffraction patterns from reference compounds. Even with the relatively low scattering contrast that is available at the K-edges, it was possible to determine the Pb/Bi distribution and probe the presence of cation site vacancies in the material. The current results indicate that resonant scattering measurements at high-energy K-edges are a viable, and perhaps preferable, route to site occupancies when absorption from the sample or sample environment/container is a major barrier to the acquisition of high-quality resonant scattering data at lower-energy edges

  17. The crystal structure of Kirkiite, Pb10Bi3As3S19

    DEFF Research Database (Denmark)

    Makovicky, Emil; Balic Zunic, Tonci; Karanovic, Ljiljana

    2006-01-01

    and chemical analysis resulted in comparable formulae, Pb10Bi2.16As3.84S19 and Pb10.08Bi2.55Sb0.13As2.91S19, respectively, which are close to the ideal formula Pb10Bi3As3S19. The crystal lattice shows a pseudohexagonal symmetry, which is the cause of common twinning in this mineral. The main twin-law has (20...... layers parallel to (083) of kirkiite; the slabs are unit-cell-twinned on (010) refl ection planes. The structure contains one split As position, and two additional sites that could accommodate both As and Bi. The As,Bi distribution over these two sites is determined by the trapezoidal distortion...... of the half-octahedral coordination environment inside the tightly bonded double layers of the PbS-SnS archetype slabs. Owing to the stoichiometry requirements in this structure, Bi must also substitute for 1/11 of the Pb sites. Bond-valence calculations and the volumes of coordination polyhedra show...

  18. Pressure induced phase transition in Pb6Bi2S9

    DEFF Research Database (Denmark)

    Olsen, Lars Arnskov; Friese, Karen; Makovicky, Emil

    2011-01-01

    consists of two types of moduli with SnS/TlI archetype structure in which the Pb and Bi lone pairs are strongly expressed. The mechanism of the phase transition is described in detail and the results are compared to the closely related phase transition in Pb3Bi2S6 (lillianite).......The crystal structure of Pb6Bi2S9 is investigated at pressures between 0 and 5.6 GPa with X-ray diffraction on single-crystals. The pressure is applied using diamond anvil cells. Heyrovskyite (Bbmm, a = 13.719(4) Å, b = 31.393(9) Å, c = 4.1319(10) Å, Z = 4) is the stable phase of Pb6Bi2S9...... at ambient conditions and is built from distorted moduli of PbS-archetype structure with a low stereochemical activity of the Pb2+ and Bi3+ lone electron pairs. Heyrovskyite is stable until at least 3.9 GPa and a first-order phase transition occurs between 3.9 and 4.8 GPa. A single-crystal is retained after...

  19. Growth of (100)-highly textured BaBiO{sub 3} thin films on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ferreyra, C. [GIyA and INN, CNEA, Av. Gral Paz 1499, 1650 San Martín, Buenos Aires (Argentina); Departamento de Física, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 1, Ciudad Universitaria, Buenos Aires (Argentina); Marchini, F. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Departamento de Química Inorgánica, Analítica y Química-Física, INQUIMAE-CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, Buenos Aires (Argentina); Granell, P. [INTI, CMNB, Av. Gral Paz 5445, B1650KNA San Martín, Buenos Aires (Argentina); Golmar, F. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); INTI, CMNB, Av. Gral Paz 5445, B1650KNA San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología, UNSAM, Campus Miguelete, 1650 San Martín, Buenos Aires (Argentina); Albornoz, C. [GIyA and INN, CNEA, Av. Gral Paz 1499, 1650 San Martín, Buenos Aires (Argentina); and others

    2016-08-01

    We report on the growth and characterization of non-epitaxial but (100)-highly textured BaBiO{sub 3} thin films on silicon substrates. We have found the deposition conditions that optimize the texture, and show that the textured growth is favoured by the formation of a BaO layer at the first growth stages. X-ray diffraction Φ-scans, together with the observation that the same textured growth is found on films grown on Pt and SiO{sub 2} buffered Si, demonstrate the absence of epitaxy. Finally, we have shown that our (100)-oriented BaBiO{sub 3} films can be used as suitable buffers for the growth of textured heterostructures on silicon, which could facilitate the integration of potential devices with standard electronics. - Highlights: • BaBiO{sub 3} thin films were grown on Si substrates and characterized. • Films prepared using optimized conditions are highly textured in the (100) direction. • The absence of in-plane texture was demonstrated by X-ray diffraction. • Our films are suitable buffers for the growth of (100)-textured oxide heterostructures.

  20. Prediction of phase equilibria and thermal analysis in the Bi-Cu-Pb ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Manasijevic, Dragan [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia); Mitovski, Aleksandra, E-mail: amitovski@tf.bor.ac.rs [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia); Minic, Dusko [University of Pristina, Faculty of Technical Sciences, 38220 Kosovska Mitrovica (Serbia); Zivkovic, Dragana; Marjanovic, Sasa [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia); Todorovic, Radisa [Institute of Mining and Metallurgy, Zeleni Bulevar 35, 19210 Bor (Serbia); Balanovic, Ljubisa [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia)

    2010-05-20

    The knowledge about phase diagram of the Bi-Cu-Pb ternary system is of importance in development of copper-lead based bearing materials, soldering and in refining of copper and lead. In this work, the phase diagram of the Bi-Cu-Pb ternary system was calculated by the CALPHAD method using binary thermodynamic parameters included in the COST 531 database. The results include liquidus projection, invariant equilibria and three vertical sections with molar ratio Cu:Pb = 1, Cu:Pb = 1:3 and Bi:Cu = 1. Alloys, with compositions along three predicted vertical sections, were measured using differential scanning calorimetry (DSC). The experimentally determined phase transition temperatures were compared with calculated results and good mutual agreement was noticed.

  1. Prediction of phase equilibria and thermal analysis in the Bi-Cu-Pb ternary system

    International Nuclear Information System (INIS)

    Manasijevic, Dragan; Mitovski, Aleksandra; Minic, Dusko; Zivkovic, Dragana; Marjanovic, Sasa; Todorovic, Radisa; Balanovic, Ljubisa

    2010-01-01

    The knowledge about phase diagram of the Bi-Cu-Pb ternary system is of importance in development of copper-lead based bearing materials, soldering and in refining of copper and lead. In this work, the phase diagram of the Bi-Cu-Pb ternary system was calculated by the CALPHAD method using binary thermodynamic parameters included in the COST 531 database. The results include liquidus projection, invariant equilibria and three vertical sections with molar ratio Cu:Pb = 1, Cu:Pb = 1:3 and Bi:Cu = 1. Alloys, with compositions along three predicted vertical sections, were measured using differential scanning calorimetry (DSC). The experimentally determined phase transition temperatures were compared with calculated results and good mutual agreement was noticed.

  2. Conceptual design tool development for a Pb-Bi cooled reactor

    International Nuclear Information System (INIS)

    Lee, K. G.; Chang, S. H.; No, H. C.; Chunm, M. H.

    2000-01-01

    Conceptual design is generally ill-structured and mysterious problem solving. This leads the experienced experts to be still responsible for the most of synthesis and analysis task, which are not amenable to logical formulations in design problems. Especially because a novel reactor such as a Pb-Bi cooled reactor is going on a conceptual design stage, it will be very meaningful to develop the conceptual design tool. This tool consists of system design module with artificial intelligence, scaling module, and validation module. System design decides the optimal structure and the layout of a Pb-Bi cooled reactor, using design synthesis part and design analysis part. The designed system is scaled to be optimal with desired power level, and then the design basis accidents (Dbase) are analyzed in validation module. Design synthesis part contains the specific data for reactor components and the general data for a Pb-Bi cooled reactor. Design analysis part contains several design constraints for formulation and solution of a design problem. In addition, designer's intention may be externalized through emphasis on design requirements. For the purpose of demonstration, the conceptual design tool is applied to a Pb-Bi cooled reactor with 125 M Wth of power level. The Pb-Bi cooled reactor is a novel reactor concept in which the fission-generated heat is transferred from the primary coolant to the secondary coolant through a reactor vessel wall of a novel design. The Pb-Bi cooled reactor is to deliver 125 M Wth per module for 15 effective full power years without any on-site fuel handling. The conceptual design tool investigated the feasibility of a Pb-Bi cooled reactor. Application of the conceptual design tool will be, in detail, presented in the full paper. (author)

  3. Tuning the electronic properties at the surface of BaBiO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ferreyra, C. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Departamento de Física, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Guller, F.; Llois, A. M.; Vildosola, V. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Marchini, F.; Williams, F. J. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Departamento de Química Inorgánica, Analítica y Química-Física, INQUIMAE-CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, Buenos Aires (Argentina); Lüders, U. [CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Boulevard Maréchal Juin, 14050 Caen Cedex 4 (France); Albornoz, C. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Leyva, A. G. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología, UNSAM, Campus Miguelete, (1650), San Martín, Buenos Aires (Argentina); and others

    2016-06-15

    The presence of 2D electron gases at surfaces or interfaces in oxide thin films remains a hot topic in condensed matter physics. In particular, BaBiO{sub 3} appears as a very interesting system as it was theoretically proposed that its (001) surface should become metallic if a Bi-termination is achieved (Vildosola et al., PRL 110, 206805 (2013)). Here we report on the preparation by pulsed laser deposition and characterization of BaBiO{sub 3} thin films on silicon. We show that the texture of the films can be tuned by controlling the growth conditions, being possible to stabilize strongly (100)-textured films. We find significant differences on the spectroscopic and transport properties between (100)-textured and non-textured films. We rationalize these experimental results by performing first principles calculations, which indicate the existence of electron doping at the (100) surface. This stabilizes Bi ions in a 3+ state, shortens Bi-O bonds and reduces the electronic band gap, increasing the surface conductivity. Our results emphasize the importance of surface effects on the electronic properties of perovskites, and provide strategies to design novel oxide heterostructures with potential interface-related 2D electron gases.

  4. Ab initio study of properties of BaBiO3 at high pressure

    Science.gov (United States)

    Martoňák, Roman; Ceresoli, Davide; Kagayama, Tomoko; Tosatti, Erio

    BaBiO3 is a mixed-valence perovskite which escapes metallic state by creating a Bi-O bond disproportionation or CDW pattern, resulting in a Peierls semiconductor with gap of nearly 1 eV at zero pressure. Evolution of structural and electronic properties at high pressure is, however, largely unknown. Pressure, it might be natural to expect, could reduce the bond-disproportionation and bring the system closer to metalicity or even superconductivity. We address this question by ab initio DFT methods based on GGA and hybrid functionals in combination with crystal structure prediction techniques based on genetic algorithms. We analyze the pressure evolution of bond disproportionation as well as other order parameters related to octahedra rotation for various phases in connection with corresponding evolution of the electronic structure. Results indicate that BaBiO3 continues to resist metalization also under pressure, through structural phase transitions which sustain and in fact increase the diversity of length of Bi-O bonds for neighboring Bi ions, in agreement with preliminary high pressure resistivity data. R.M. Slovak Research and Development Agency Contract APVV-15-0496, VEGA project No. 1-0904-15; E.T. ERC MODPHYSFRICT Advanced Grant No. 320796.

  5. Superconductivity in Ba sub 1 sub - sub x K sub x BiO sub 3 : possible scenario of spatially separated Fermi-Bose mixture

    CERN Document Server

    Menushenkov, A P; Kuznetsov, A V; Kagan, M Y

    2001-01-01

    A new scenario for the metal-insulator phase transition and superconductivity in the perovskite-like bismuthates Ba sub 1 sub - sub x K sub x BiO sub 3 (BKBO) is proposed. It is shown that two types of charge carriers, the local pairs (real-space bosons) and the itinerant electrons, exist in the metallic compound BKBO (x >= 0.37). The real-space bosons are responsible for the charge transport in semiconducting BaBiO sub 3 and for superconductivity in the metallic BKBO. The appearance of the Fermi-liquid state as the percolation threshold is overcome (x >= 0.37) explains the observed metal-insulator phase transition. Because bosons and fermions occupy different types of the octahedral BiO sub 6 complexes, they are separated in real space, and therefore, the spatially separated Fermi-Bose mixture of a new type is likely to be realized in the bismuthates. The nature of superconductivity is consistently explained in the framework of this scenario. A new superconducting oxide Ba sub 1 sub - sub x La sub x PbO sub ...

  6. Quantum oscillations and Dirac dispersion in the BaZnBi2 semimetal guaranteed by local Zn vacancy order

    Science.gov (United States)

    Zhao, K.; Golias, E.; Zhang, Q. H.; Krivenkov, M.; Jesche, A.; Gu, L.; Rader, O.; Mazin, I. I.; Gegenwart, P.

    2018-03-01

    We have synthesized single crystals of Dirac semimetal candidates A ZnBi2 with A =Ba and Sr. In contrast to A =Sr , the Ba material displays a local Zn vacancy ordering, which makes the observation of quantum oscillations in out-of-plane magnetic fields possible. As a Dirac semimetal candidate, BaZnBi2 exhibits a small cyclotron electron mass, high quantum mobility, and nontrivial Berry phases. Three Dirac dispersions are observed by angle-resolved photoemission spectroscopy and identified by first-principles band-structure calculations. Compared to A Mn(Bi/Sb) 2 systems which host Mn magnetic moments, BaZnBi2 acts as a nonmagnetic analog to investigate the intrinsic properties of Dirac fermions in this structure family.

  7. Thermoelectric properties and thermal stability of Bi-doped PbTe single crystal

    Science.gov (United States)

    Chen, Zhong; Li, Decong; Deng, Shuping; Tang, Yu; Sun, Luqi; Liu, Wenting; Shen, Lanxian; Yang, Peizhi; Deng, Shukang

    2018-06-01

    In this study, n-type Bi-doped single-crystal PbTe thermoelectric materials were prepared by melting and slow cooling method according to the stoichiometric ratio of Pb:Bi:Te = 1-x:x:1 (x = 0, 0.1, 0.15, 0.2, 0.25). The X-ray diffraction patterns of Pb1-xBixTe samples show that all main diffraction peaks are well matched with the PbTe matrix, which has a face-centered cubic structure with the space group Fm 3 bar m . Electron probe microanalysis reveals that Pb content decreases gradually, and Te content remains invariant basically with the increase of Bi content, indicating that Bi atoms are more likely to replace Pb atoms. Thermal analysis shows that the prepared samples possess relatively high thermal stability. Simultaneously, transmission electron microscopy and selected area electron diffraction pattern indicate that the prepared samples have typical single-crystal structures with good mechanical properties. Moreover, the electrical conductivity of the prepared samples improved significantly compared with that of the pure sample, and the maximum ZT value of 0.84 was obtained at 600 K by the sample with x = 0.2.

  8. Pressure induced superconductivity in the antiferromagnetic Dirac material BaMnBi2

    OpenAIRE

    Huimin Chen; Lin Li; Qinqing Zhu; Jinhu Yang; Bin Chen; Qianhui Mao; Jianhua Du; Hangdong Wang; Minghu Fang

    2017-01-01

    The so-called Dirac materials such as graphene and topological insulators are a new class of matter different from conventional metals and (doped) semiconductors. Superconductivity induced by doing or applying pressure in these systems may be unconventional, or host mysterious Majorana fermions. Here, we report a successfully observation of pressure-induced superconductivity in an antiferromagnetic Dirac material BaMnBi2 with T c of ~4?K at 2.6?GPa. Both the higher upper critical field, ? 0 H...

  9. Syntheses of the Bi(Pb)-2212 high-Tc superconductor through a novel oxide nitrate route

    International Nuclear Information System (INIS)

    Gibson, K; Ziegler, P; Meyer, H-J

    2004-01-01

    A novel route is presented for the syntheses of Bi 2 Sr 2 CaCu 2 O x (Bi-2212) and (Bi,Pb) 2 Sr 2 CaCu 2 O x (Bi,Pb-2212). Mixtures of oxides, nitrates and carbonates with approximate 2:2:1:2 metal ion compositions are dissolved in HNO 3 and dried at 200 deg. C in air. Afterwards they are reacted under their in situ generated NO x atmosphere in a closed reactor (Staurohr). This reaction forces the system to form the nitrate precursors (Bi,Sr,Ca) 2 O 2 NO 3 /CuO and (Bi,Pb,Sr,Ca) 2 O 2 NO 3 /CuO, respectively. In the final reaction stage these mixtures are converted into Bi(Pb)-2212 under NO x discharge in air. All important reaction stages and phase compositions are analysed by means of powder XRD

  10. Simultaneous determination of picogram per gram concentrations of Ba, Pb and Pb isotopes in Greenland ice by thermal ionisation mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Jimi, Salah I.; Rosman, Kevin J.R.; Candelone, Jean-Pierre; Burn, Laurie J. [Curtin University of Technology, Department of Imaging and Applied Physics, Perth (Australia); Hong, Sungmin [Polar Research Centre, Korean Ocean Research and Development Institute, Ansan, P.O. Box 29, Seoul (Korea); Boutron, Claude F. [Domaine Universitaire, Laboratoire de Glaciologie et Geophysique du l' Environnement, 54 rue Moliere, Saint Martin d' Heres (France); UFR de Mecanique, Universite Joseph Fourier de Grenoble (Institut Universitaire de France), Domaine Universitaire, Grenoble (France)

    2008-01-15

    A technique has been developed to simultaneously measure picogram per gram concentrations of Ba and Pb by isotope dilution mass spectrometry, as well as Pb isotopic ratios in polar ice by thermal ionisation mass spectrometry. BaPO{sup +}{sub 2} and Pb{sup +} ions were employed for these determinations. A calibrated mixture of enriched {sup 205}Pb and {sup 137}Ba was added to the samples providing an accuracy of better than approximately 2% for Pb/Ba element ratio determinations. Interference by molecular ions in the Pb mass spectrum occurred only at {sup 204}Pb and {sup 205}Pb, but these contributions were negligible in terms of precisions expected on picogram-sized Pb samples. The technique is illustrated with measurements on Greenland firn, using a drill-core section that includes the Laki volcanic eruption of 1783-1784. The data show deviations from the element concentrations indicating volatile metal enrichments, but the Pb isotopic signature of the Laki lava could not be identified. (orig.)

  11. Size dependent magnetic and electrical properties of Ba-doped nanocrystalline BiFeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Mehedi, E-mail: mhrizvi@gce.buet.ac.bd; Hakim, M. A.; Zubair, M. A.; Hussain, A.; Islam, Md. Fakhrul [Department of Glass and Ceramic Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh); Basith, M. A., E-mail: mabasith@phy.buet.ac.bd [Department of Physics, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Hossain, Md. Sarowar [S. N. Bose National Centre for Basic Sciences, Salt Lake City, Kolkata, West Bengal 700098 (India); Ahmmad, Bashir [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510 (Japan)

    2016-03-15

    Improvement in magnetic and electrical properties of multiferroic BiFeO{sub 3} in conjunction with their dependence on particle size is crucial due to its potential applications in multifunctional miniaturized devices. In this investigation, we report a study on particle size dependent structural, magnetic and electrical properties of sol-gel derived Bi{sub 0.9}Ba{sub 0.1}FeO{sub 3} nanoparticles of different sizes ranging from ∼ 12 to 49 nm. The substitution of Bi by Ba significantly suppresses oxygen vacancies, reduces leakage current density and Fe{sup 2+} state. An improvement in both magnetic and electrical properties is observed for 10 % Ba-doped BiFeO{sub 3} nanoparticles compared to its undoped counterpart. The saturation magnetization of Bi{sub 0.9}Ba{sub 0.1}FeO{sub 3} nanoparticles increase with reducing particle size in contrast with a decreasing trend of ferroelectric polarization. Moreover, a first order metamagnetic transition is noticed for ∼ 49 nm Bi{sub 0.9}Ba{sub 0.1}FeO{sub 3} nanoparticles which disappeared with decreasing particle size. The observed strong size dependent multiferroic properties are attributed to the complex interaction between vacancy induced crystallographic defects, multiple valence states of Fe, uncompensated surface spins, crystallographic distortion and suppression of spiral spin cycloid of BiFeO{sub 3}.

  12. Pb induces superconductivity in Bi2Se3 analyzed by point contact spectroscopy

    OpenAIRE

    Arevalo-López, P.; López-Romero, R. E.; Escudero, R.

    2015-01-01

    Some topological insulators become superconducting when doped with Cu and Pd. Superconductivity in a non-superconductor may be induced by proximity effect: i.e. Contacting a non-superconductor with a superconductor. The superconducting macroscopic wave function will induce electronic pairing into the normal compound. In the simplest topological insulator, Bi$_2$Se$_3$, superconductivity may be induced with Pb. We studied with point contact junctions formed by contacting Bi$_2$Se$_3$ crystals ...

  13. Fabrication and electrical investigations of Pb-doped BaTiO_3 ceramics

    International Nuclear Information System (INIS)

    Sareecha, N.; Shah, W.A.; Maqsood, A.; Anis-ur-Rehman, M.; Latif Mirza, M.

    2017-01-01

    Electrical properties of Pb doped BaTiO_3; PBT are investigated in the wide range of temperatures (40–700 °C) at 1 kHz frequency. PBT ceramics were fabricated through solid state sintering method. Pre fired BaTiO_3 prepared with Ba/Ti molar ratio of 0.98 was doped with PbCO_3 (<1 mole %). XRD patterns indicated perovskite phase with tetragonal structures (P4mm). Morphological studies (SEM) revealed grain development with increasing lead contents. With lead doping and its variation, Curie temperature (T_C) was shifted from 120 to 200 °C with broad dielectric constant peaks and dielectric anomalies with relaxor behavior were observed. Resistivity decreased with increasing temperature, all specimens showed semiconductor behavior with negative temperature coefficient of resistivity (NTCR) characteristics. Mobility of electrons increased with thermal activation due to hopping of charge carriers from one site to another. Ohmic conductivities and associated activation energies were evaluated by impedance spectroscopy. Conductivity followed the Arrhenius law with E_a = 1.187–1.169 eV which can be attributed to the ionic conduction owning to doubly ionized oxygen vacancies. Well-defined hysteresis P-E loops measured at room temperature depicted ferroelectric properties of the materials. - Graphical abstract: Temperature dependence of dielectric constant (Ɛ′) and resistivity (ρ) for pure and Pb-doped BaTiO_3 ceramics at 1 k Hz frequency. - Highlights: • Pb-doped BaTiO_3ceramics were fabricated through solid state sintering. • Electrical properties were studied at the temperatures 40–700 °C at 1 kHz. • Specimens showed negative temperature coefficient of resistivity characteristics. • Conductivity followed the Arrhenius law with E_a = 1.187–1.169 eV. • Ionic conduction was supposed to be responsible for conduction process.

  14. Fabrication and electrical investigations of Pb-doped BaTiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sareecha, N., E-mail: nsareecha@hotmail.com [Laboratory of Physical Chemistry, Department of Chemistry, Islamia University of Bahawalpur (Pakistan); Shah, W.A. [Glass and Ceramics Research Centre, PCSIR Laboratories Complex, Ferozpur Road, Lahore 54600 (Pakistan); Maqsood, A. [Nano Scale Physics Laboratory, Department of Physics, Air University, PAF Complex E-9, Islamabad (Pakistan); Anis-ur-Rehman, M. [Applied Thermal Physics Laboratory, COMSATS Institute of Information and Technology, Park Road, Islamabad 44000 (Pakistan); Latif Mirza, M. [Laboratory of Physical Chemistry, Department of Chemistry, Islamia University of Bahawalpur (Pakistan)

    2017-06-01

    Electrical properties of Pb doped BaTiO{sub 3}; PBT are investigated in the wide range of temperatures (40–700 °C) at 1 kHz frequency. PBT ceramics were fabricated through solid state sintering method. Pre fired BaTiO{sub 3} prepared with Ba/Ti molar ratio of 0.98 was doped with PbCO{sub 3} (<1 mole %). XRD patterns indicated perovskite phase with tetragonal structures (P4mm). Morphological studies (SEM) revealed grain development with increasing lead contents. With lead doping and its variation, Curie temperature (T{sub C}) was shifted from 120 to 200 °C with broad dielectric constant peaks and dielectric anomalies with relaxor behavior were observed. Resistivity decreased with increasing temperature, all specimens showed semiconductor behavior with negative temperature coefficient of resistivity (NTCR) characteristics. Mobility of electrons increased with thermal activation due to hopping of charge carriers from one site to another. Ohmic conductivities and associated activation energies were evaluated by impedance spectroscopy. Conductivity followed the Arrhenius law with E{sub a} = 1.187–1.169 eV which can be attributed to the ionic conduction owning to doubly ionized oxygen vacancies. Well-defined hysteresis P-E loops measured at room temperature depicted ferroelectric properties of the materials. - Graphical abstract: Temperature dependence of dielectric constant (Ɛ′) and resistivity (ρ) for pure and Pb-doped BaTiO{sub 3} ceramics at 1 k Hz frequency. - Highlights: • Pb-doped BaTiO{sub 3}ceramics were fabricated through solid state sintering. • Electrical properties were studied at the temperatures 40–700 °C at 1 kHz. • Specimens showed negative temperature coefficient of resistivity characteristics. • Conductivity followed the Arrhenius law with E{sub a} = 1.187–1.169 eV. • Ionic conduction was supposed to be responsible for conduction process.

  15. Growth of Ba1-zSrzBiO3-y single crystals and the prospects for its application for liquid phase epitaxy of Ba1-xKxBiO3-δ superconductor

    International Nuclear Information System (INIS)

    Soldatov, A.G.; Barilo, S.N.; Shiryaev, S.V.; Finskaya, V.M.

    2002-01-01

    In order to get a substrate for liquid phase epitaxy of the Ba 1-x K x BiO 3-δ (BKBO) superconducting films a possibility to grow single crystals of the Ba 1-z Sr z BiO 3-y (BSBO) solid solution series was investigated. The BSBO crystals with z = 0; 0.2; 0.29; 0.45; 0.49; 0.50; 0.54; 0.58 were obtained by crystallization from melt. The temperature versus composition phase diagram of the BaO · 1/2Bi 2 O 3 -SrO · 1/2Bi 2 O 3 system was constructed. A comparative analysis of the effect of cation composition and oxygen nonstoichiometry on the BSBO lattice parameters was carried out. The growth features of superconducting BKBO films onto BSBO substrates are discussed [ru

  16. A comparative study of the Aurivillius phase ferroelectrics CaBi 4Ti 4O 15 and BaBi 4Ti 4O 15

    Science.gov (United States)

    Tellier, J.; Boullay, Ph.; Manier, M.; Mercurio, D.

    2004-06-01

    The room temperature structures of the four-layer Aurivillius phase ferroelectrics CaBi 4Ti 4O 15 and BaBi 4Ti 4O 15 are determined by means of single crystal X-ray diffraction. Regarding the CaBi 4Ti 4O 15 phase, in agreement with the tolerance factor, a significant deformation of the perovskite blocks is observed. The rotation system of the octahedra is typical from even layer Aurivillius phases and leads to the use of the space group A2 1am. For the BaBi 4Ti 4O 15 phase, only a weak variation with respect to the F2 mm space group can be suggested from single crystal X-ray diffraction. A significant presence of Ba atoms in the [ M2O 2] slabs is confirmed in agreement with the previous works but specific Ba 2+ and Bi 3+ sites have to be considered due to the large difference in bounding requirement of these cations. Possible origins for the ferroelectric relaxor behavior of the Ba-based compound are discussed in view of the presented structural analyses.

  17. Relaxations in Ba{sub 2}BiTaO{sub 6} ceramics investigated by impedance and electric modulus spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Joao Elias Figuereido Soares [Departamento de Fisica - CCET, Universidade Federal do Maranhao, Campus do Bacanga, 65085-580, Sao Luis -MA (Brazil); Paschoal, Carlos William de Araujo, E-mail: paschoal@ufma.br [Departamento de Fisica - CCET, Universidade Federal do Maranhao, Campus do Bacanga, 65085-580, Sao Luis -MA (Brazil); Silva, Eder Nascimento [Departamento de Fisica - CCET, Universidade Federal do Maranhao, Campus do Bacanga, 65085-580, Sao Luis -MA (Brazil); Mince, Kathryn A.; Lufaso, Michael W. [Department of Chemistry, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224 (United States)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer We have confirmed that the relaxation observed in Ba{sub 2}BiTaO{sub 6} is due to the conduction mechanism. Black-Right-Pointing-Pointer The conduction mechanism is the oxygen vacancies hopping. Black-Right-Pointing-Pointer We have explained because the activation energy for the Ba{sub 2}BiTaO{sub 6} is lower than observed for Ba{sub 2}BiSbO{sub 6} with basis in zero-point energy of both materials. Black-Right-Pointing-Pointer We have showed that a minor secondary phase is a minor secondary phase, which is common when the BBTO is obtained by ceramic method under air, does not change significantly the electrical properties of BBTO. -- Abstract: Impedance spectroscopy analysis of the dielectric properties of a Ba{sub 2}BiTaO{sub 6} ceramic was performed in the temperature range from room temperature to 500 K. The sample was prepared using conventional solid state synthesis under air and the X-ray diffraction shows the presence of Ba{sub 5}Ta{sub 4}O{sub 15} as a minor secondary phase (0.09%). The impedance data clearly show contributions of the grain and grain boundary. The results indicate that the conduction in Ba{sub 2}BiTaO{sub 6} is due to hopping of oxygen vacancies and that the impurities not influence the conduction mechanism.

  18. Phase formations in the KOH-BaO2-KI(I2)-Bi2O3 system

    International Nuclear Information System (INIS)

    Klinkova, L.A.; Barkovskij, N.V.; Nikolajchik, V.I.

    2004-01-01

    Phase composition of electrochemical synthesis products in the system KOH-BaO 2 -KI(I 2 )-Bi 2 O 3 and its influence on superconducting properties of bismuth-containing oxides are studied by the methods of X-ray phase and elementary analyses, electron diffraction in transmission electron microscope and by measuring temperature dependence of magnetic susceptibility. It was been ascertained that in the presence of iodine introduced as KI or I 2 oxoiodides KBi 6 O 9 I and Bi 5 O 7 I are formed in the system above, giving rise to a change in the composition of synthesis products in KOH-BaO 2 -Bi 2 O 3 matrix system towards formation of superconducting oxides K n Ba m Bi m+n O y rich in bismuth, which are characterized by low values of superconducting transition point [ru

  19. Study of the structure and ferroelectric behavior of BaBi4-xLaxTi4O15 ceramics

    Science.gov (United States)

    Khokhar, Anita; Goyal, Parveen K.; Thakur, O. P.; Sreenivas, K.

    2015-06-01

    The structure and ferroelectric properties of Lanthanum substituted barium bismuth titanate BaBi4-xLaxTi4O15 (0 ≤ x ≤ 0.5) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material. The distribution of lanthanum into the perovskite layers and (Bi2O2)2+ layers of BaBi4Ti4O15 ceramics have been revealed through Raman spectroscopy. At lower value of x, it is seen that La3+ ions prefer to substitute A-site Bi3+ ions in the perovskite layers while for higher x values, La3+ ions get incorporated into the (Bi2O2)2+ layers. A critical La content of x ˜ 0.2 in BaBi4-xLaxTi4O15 is seen to exhibit a large remnant polarization (Pr) with low coercive field (Ec). The improvement in the ferroelectric properties of La substituted BaBi4Ti4O15 ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of lanthanum ion.

  20. Pressure induced superconductivity in the antiferromagnetic Dirac material BaMnBi2.

    Science.gov (United States)

    Chen, Huimin; Li, Lin; Zhu, Qinqing; Yang, Jinhu; Chen, Bin; Mao, Qianhui; Du, Jianhua; Wang, Hangdong; Fang, Minghu

    2017-05-09

    The so-called Dirac materials such as graphene and topological insulators are a new class of matter different from conventional metals and (doped) semiconductors. Superconductivity induced by doing or applying pressure in these systems may be unconventional, or host mysterious Majorana fermions. Here, we report a successfully observation of pressure-induced superconductivity in an antiferromagnetic Dirac material BaMnBi 2 with T c of ~4 K at 2.6 GPa. Both the higher upper critical field, μ 0 H c2 (0) ~ 7 Tesla, and the measured current independent of T c precludes that superconductivity is ascribed to the Bi impurity. The similarity in ρ ab (B) linear behavior at high magnetic fields measured at 2 K both at ambient pressure (non-superconductivity) and 2.6 GPa (superconductivity, but at the normal state), as well as the smooth and similar change of resistivity with pressure measured at 7 K and 300 K in zero field, suggests that there may be no structure transition occurred below 2.6 GPa, and superconductivity observed here may emerge in the same phase with Dirac fermions. Our findings imply that BaMnBi 2 may provide another platform for studying SC mechanism in the system with Dirac fermions.

  1. Phase relations in the pseudobinary BaO-PbO2 system. Part 1: synthesis and characterization of compounds

    International Nuclear Information System (INIS)

    Rama Rao, G.V.; Suganthi, S.; Asokamani, R.; Azad, A.M.; Sreedharan, O.M.

    1993-01-01

    The compounds BaPbO 3 and Ba 2 PbO 4 are among the important basic materials for the copper less ceramic superconductors. Hence it was necessary to identify the best process of synthesis with optimum process temperature. For this purpose preparation of BaPbO 3 and Ba 2 PbO 4 was carried out by solid-state, solid-solution and sol-gel processes. Products so synthesised were characterized by x-ray diffraction, infra red spectroscopy and thermal analyses. Particle size measurements were carried out by He-Ne laser light scattering technique for a possible correlation with sintering behaviour. Merits and limitations of the different processes were compared. The reaction process was studied by thermal analysis (TG and DTA) and infra red spectroscopy. The solid solution process has reduced the formation temperature by a margin of 200-300 deg to a value of 773K compared to other methods. The sol-gel processing approach did not favour the formation of Ba 2 PbO 4 . While solid solution route appears to be the best for synthesis of pure B 2 PbO 4 , sol-gel processes are most appropriate for synthesizing BaPbO 3 with very fine particle size distribution. (author). 24 refs., 3 figs., 4 tabs

  2. Transverse peltier effect in Pb-Bi{sub 2}Te{sub 3} multilayer structures

    Energy Technology Data Exchange (ETDEWEB)

    Reitmaier, Christina; Walther, Franziska; Kyarad, Amir; Lengfellner, Hans [University of Regensburg (Germany)

    2009-07-01

    Metal-semiconductor multilayer structures show, according to model calculations, large anisotropy in their electrical and thermal transport properties. Multilayer stacks consisting of alternating layers of Pb and n-type Bi{sub 2}Te{sub 3} and prepared by a heating procedure displayed large thermoelectric anisotropy up to {delta}S{approx}200 {mu} V/K, depending on the thickness ratio p=d{sub BiTe}/d{sub Pb}, where d{sub BiTe} and d{sub Pb} are the thicknesses of Bi{sub 2}Te{sub 3} and Pb layers, respectively. From multilayer stacks, tilted samples with layers inclined with respect to the sample surface where obtained by cutting stacks obliquely to the stack axis. Non-zero off-diagonal elements in the Seebeck-tensor describing the thermopower of tilted samples allow for the occurance of a transverse Peltier effect. Experimental results demonstrate cooling by the transverse Peltier effect and are compared to model calculations.

  3. Safety design of Pb-Bi-cooled direct contact boiling water fast reactor (PBWFR)

    International Nuclear Information System (INIS)

    Takahashi, Minoru; Uchida, Shoji; Yamada, Yumi; Koyama, Kazuya

    2008-01-01

    In Pb-Bi-cooled direct contact boiling water small fast reactor (PBWFR), steam is generated by direct contact of feedwater with primary Pb-Bi coolant above the core, and Pb-Bi coolant is circulated by steam lift pump in chimneys. Safety design has been developed to show safety features of PBWFR. Negative void reactivity is inserted even if whole of the core and upper plenum are voided hypothetically by steam intrusion from above. The control rod ejection due to coolant pressure is prevented using in-vessel type control rod driving mechanism. At coolant leak from reactor vessel and feedwater pipes, Pb-Bi coolant level in the reactor vessel required for decay heat removal is kept using closed guard vessel. Dual pipes for feedwater are employed to avoid leak of water. Although there is no concern of loss of flow accident due to primary pump trip, feedwater pump trip initiates loss of coolant flow (LOF). Injection of high pressure water slows down the flow coast down of feedwater at the LOF event. The unprotected loss of flow and heat sink (ATWS) has been evaluated, which shows that the fuel temperatures are kept lower than the safety limits. (author)

  4. Calorimetric investigation of (Pb0.45Bi0.55)-U system

    International Nuclear Information System (INIS)

    Agarwal, Renu; Samui, Pradeep; Mukerjee, S.K.; Ramakumar, K.L.

    2016-01-01

    Lead-bismuth eutectic (LBE) is being considered as a coolant of future high temperature reactors. As lead and bismuth are good spallation target material, they are planned to be used in accelerator driven reactor systems (ADS). Under the clad breach conditions these elements may come in direct contact with uranium of metallic fuel. In our labs, we had earlier investigated binary interactions of U-Pb and U-Bi. To assess interaction behaviour of 'U' with the eutectic melt, it was planned to measure enthalpy of mixing of LBE-U and compares it with the binary mixing. SEM-EDS studies of the product formed after mixing of LBE and 'U' were carried out to establish coexisting phases and their compositions. UPb 3 is Pb-rich compound of U-Pb and UBi 2 is Bi-rich compound of U-Bi. So addition of 'U' in (Pb 0.45 Bi 0.55 ) will result in formation of the more stable compound among UPb 3 and UBi 2

  5. Pionic 4f-3d X-rays from 208Pb and 209Bi

    International Nuclear Information System (INIS)

    Olin, A.; Forsman, J.W.; MacDonald, J.A.; Marshall, G.M.; Numao, T.; Poffenberger, P.R.; Van Esbroek, P.; Kunselman, A.R.; Olaniyi, B.H.

    1985-01-01

    The X-ray energies and widths of the pionic 4f-3d and 5g-4f transitions have been measured in 208 Pb and 209 Bi. The 3d widths obtained are in reasonable agreement with theory, and do not support the anomalously small values previously reported. (orig.)

  6. Positron lifetime studies of 100-MeV oxygen irradiated Pb-doped Bi-2223 superconductors

    NARCIS (Netherlands)

    Banerjee, T.; Viswanath, R.N.; Kanjilal, D.; Kumar, R.; Ramasamy, S.

    2000-01-01

    Positron lifetime studies have been carried out for unirradiated and 100-MeV oxygen ion irradiated Pb-doped Bi-2223 superconductors. The analysis of positron lifetime spectra revealed three lifetime components: a short lifetime, τ1 = 153–196 ps; an intermediate lifetime, τ2 = 269–339 ps; and a long

  7. Modulation-free bismuth-lead cuprate superconductors: BiPbSr1+xL1-xCuO6 and BiPbSr2Y1-xCaxCu2O8

    International Nuclear Information System (INIS)

    Manivannan, V.; Gopalakrishnan, J.; Rao, C.N.R.

    1991-01-01

    Modulation-free BiPbSrLCuO 6 (L=La, Pr, Nd) and BiPbSr 2 YCu 2 O 8 , which are isotypic with the n=1 and 2 members of the Bi 2 Sr 2 Ca n-1 Cu n O 2n+4 family, have been prepared and characterized. These parent compounds are nonsuperconducting, but when doped with holes by substitution chemistry give modulation-free superconducting cuprates of the general formulas BiPbSr 1+xL1-x CuO 6 and BiPbSr 2 Y 1-x Ca x Cu 2 O 8 , exhibiting maximum T c 's of 24 and 85 K, respectively. Significantly, the hole concentration at the maximum T c is 0.12 in the cuprate family with a single Cu-O layer and 0.22 in that with two Cu-O layers

  8. Magnetic and structural properties of Bi(2223doped by pb and Sb

    Directory of Open Access Journals (Sweden)

    H. Salamati

    1998-04-01

    Full Text Available   In a systematic approach, we have investigated the effect of the presence of Pb and Sb in the Bi site in a BSCCO (2223 phase superconductor. There are some contradictory reports in substitution of Sb in the Bi site. Some researchers report an increase in the Tc of these materials. So, we have made an accurate stoichiometry of these superconductors and selected extra pure starting materials with appropriate ratios of Pb+Sb.   The susceptility of these samples have been measured and the structures of the systems have been studied by SEM and XRD. The results of this investigation show that, Although the presence of Pb is essential for formation of (2223 phase, but addition of small amount of Sb helps to stabilize and enhance the ratio of higher phase. Our results show that, presence of Sb would raise the critical current density, but would not affect the Tc of these superconductors.

  9. Effect of Sintering Time on Superconducting Wire Bi-Pb-Sr-Ca-Cu-O With Dopant MgO Sheated Ag Using Powder in Tube Method

    Directory of Open Access Journals (Sweden)

    Hariyati Lubis

    2018-01-01

      DAFTAR PUSTAKA Abbas M.M., Abass L.K and Salman U., (2012, Influences of Sintering Time on the Tc of Bi2-xCuxPb0.3Sr2Ca2Cu3010+ High Temperature Superconductors, Energy Procedia 18, 215-224  Abbas, M.M., Abbas, L.K., Bahedh, H.S. 2015. Superconducting Properties of Bi2-SbxPb0,3Sr1,9Ba0,1Ca2Cu3O10+δ Compounds. Journal of Applied Science Research. 11. 22: 164-172 Darsono, N., Imaduddin, A., Raju, K., Yoon, D.H., (2015, Synthesis and Characterization of Bi1.6Pb0.4Sr2Ca2Cu3O7 Superconducting Oxide by High-Energy Milling, J Supercond Nov Magn. E. Chew,. (2010, Superconducting Transformer Design And Construction, University of Canterbury, Christchurch, New Zealand. March Hamadneh, I., Halim, S. A., dan Lee, C. K., (2006,  Characterization of Bi1.6Pb0.4Sr2Ca2Cu3Oy Ceramic Superconductor Prepared Via Coprecipitation Method at Different Sintering Time, J. Mater. Sci, 41: 5526-5530. Hermiz G.Y., Aljurani B.A., Beayaty M.A., (2014, Effect of Mn Substitution on the Superconducting Properties of Bi1.7Pb0,3Sr2Ca2-xMnxCu3O10+, International Journal Of Engineering and Advanced Technology (IJEAT. 3. 4: 213-217 John R Hull, (2003, Applications of high-temperature superconductors in power technology, Reports on Progress in Physics, Volume 66, Number 11 Lu, X.Y., Yi, D., Chen, H., Nagata, A. 2016. Effect of Sn, MgO and Ag2O mix-doping on the formation and superconducting properties of Bi-2223 Ag/tapes. Physics Procedia. 81: 129-132 Meretliev Sh., Sadykov K.B., Berkeliev A., (2000, Doping of High Temperature Superconductors, Turk J Phy.24: 39-48 Mohammed, N. H., Ramadhan A., Ali I. A., Ibrahim, I. H., dan Hassan, M. S, (2012, Optimizing the Preparation Conditions of Bi-2223 Superconducting Phase Using PbO and PbO2, Materials Sciences and Applications, 3: 224-233. Roumie, M., Marhaba, S., Awad R., Kork M., Hassan I., Mawassi R., (2014, Effect of Fe2O3 Nano-Oxide Addition on the Superconducting Properties of the (Bi,Pb-2223 Phase, Journal of Supercond Nov Magn, 27: 143-153 Serkan

  10. Convenient hydrothermal decomposition process for preparation of nanocrystalline mineral Cu3BiS3 and Pb1-xBi2x/3S

    International Nuclear Information System (INIS)

    Hu Junqing; Deng Bin; Wang Chunrui; Tang Kaibin; Qian Yitai

    2003-01-01

    Mineral nanocrystalline Cu 3 BiS 3 and Pb 1-x Bi 2x/3 S (or Bi 0.22 Pb 0.89 S 1.22 ) have been prepared at low synthetic temperature of 100-150 deg. C by convenient hydrothermal decomposition process. X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectra, and element analysis were used to characterize and measure the samples. The as-prepared Cu 3 BiS 3 sample consisted of whisker-like particles with an average size of 50x10 nm 2 and the Pb 1-x Bi 2x/3 S sample displayed aggregative particles with size in the range of 30-50 nm. Preliminary results showed that the prepared precursors, reaction temperature and time played a role in the formation of the final products. A possible reaction mechanism was also discussed briefly

  11. Photon mass attenuation coefficients of a silicon resin loaded with WO3, PbO, and Bi2O3 Micro and Nano-particles for radiation shielding

    Science.gov (United States)

    Verdipoor, Khatibeh; Alemi, Abdolali; Mesbahi, Asghar

    2018-06-01

    Novel shielding materials for photons based on silicon resin and WO3, PbO, and Bi2O3 Micro and Nano-particles were designed and their mass attenuation coefficients were calculated using Monte Carlo (MC) method. Using lattice cards in MCNPX code, micro and nanoparticles with sizes of 100 nm and 1 μm was designed inside a silicon resin matrix. Narrow beam geometry was simulated to calculate the attenuation coefficients of samples against mono-energetic beams of Co60 (1.17 and 1.33 MeV), Cs137 (663.8 KeV), and Ba133 (355.9 KeV). The shielding samples made of nanoparticles had higher mass attenuation coefficients, up to 17% relative to those made of microparticles. The superiority of nano-shields relative to micro-shields was dependent on the filler concentration and the energy of photons. PbO, and Bi2O3 nanoparticles showed higher attenuation compared to WO3 nanoparticles in studied energies. Fabrication of novel shielding materials using PbO, and Bi2O3 nanoparticles is recommended for application in radiation protection against photon beams.

  12. Environmental radioactivity of radon daughter's radionuclides 210Pb-210Bi-210Po

    International Nuclear Information System (INIS)

    Momoshima, N.

    2003-01-01

    Radionuclide, 210 Pb(22.3 y)- 210 Bi(5.013 d)- 210 Po(138.4 d) belongs to the uranium decay chain and widely distributed in the environment. 222 Rn escaped from the earth surface is a major source of atmospheric 210 Pb. These nuclides attach with atmospheric aerosols and are removed to the ground as wet and dry depositions. The residence time of the atmospheric aerosol, thus, was obtained by activity ratios of 210 Bi/ 210 Pb and 210 Po/ 210 Pb, showing different values. The discrepancy on the residence times are explained with inputs of 210 Po to the atmosphere other than 222 Rn emanated from the earth surface. The removal of aerosol as wet deposition occupies a significant fraction, which reaches 72% on 210 Pb and 89% on 7 Be. In the ocean, the radionuclides are used as tracer to examine dynamic processes occurring in the ocean, such as removal of particulate matter from seawater column to bottom. The 210 Pb and 210 Po concentrations in the ocean water collected off continent decreased from surface toward bottom, and the shortage on 210 Po content relative to that of 210 Po was observed at shallow ocean layers, however, the 210 Po/ 210 Pb activity ratio closed to the radioactive equilibrium at deeper layers. The 210 Pb is a very good tracer to evaluate an accumulation rate of bottom sediment in ocean, lake and river. This is called as 210 Pb dating and is successfully applicable to accumulation circumstances that bottom sediment deposits at constant rate. Most of the actual cases, simultaneous 137 Cs dating is carried out, which uses 137 Cs peak in the core as originated from radioactive fallout of nuclear tests, showing the maximum in 1963. Recently new findings on source of atmospheric 210 Po are report by laboratory experiments and environmental measurements, which proves biologically supported emission of volatile Po compounds to the atmosphere. (author)

  13. High temperature ultrasonic transducers for imaging and measurements in a liquid Pb/Bi eutectic alloy.

    Science.gov (United States)

    Kazys, Rymantas; Voleisis, Algirdas; Sliteris, Reimondas; Mazeika, Liudas; Van Nieuwenhove, Rudi; Kupschus, Peter; Abderrahim, Hamid Aït

    2005-04-01

    In some nuclear reactors or accelerator-driven systems (ADS) the core is intended to be cooled by means of a heavy liquid metal, for example, lead-bismuth (Pb/Bi) eutectic alloy. For safety and licensing reasons, an imaging method of the interior of ADS, based on application of ultrasonic waves, has thus to be developed. This paper is devoted to description of developed various ultrasonic transducers suitable for long term imaging and measurements in the liquid Pb/Bi alloy. The results of comparative experimental investigations of the developed transducers of different designs in a liquid Pb/Bi alloy up to 450 degrees C are presented. Prototypes with different high temperature piezoelectric materials were investigated: PZT, bismuth titanate (Bi4Ti3O12), lithium niobate (LiNbO3), gallium orthophosphate (GaPO4) and aluminum nitride (A1N). For acoustic coupling with the metal alloy, it was proposed to coat the active surface of the transducers by diamond like carbon (DLC). The radiation robustness was assessed by exposing the transducers to high gamma dose rates in one of the irradiation facilities at SCK x CEN. The experimental results proved that the developed transducers are suitable for long-term operation in harsh conditions.

  14. Effect of divalent (Sr, Ba) doping on the structural and magnetic properties of BiFeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Rangi, Manisha, E-mail: mrangi100@gmail.com; Sanghi, Sujata; Agarwal, Ashish; Jangra, Sandhaya; Singh, Ompal [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar, Haryana- 125001 (India)

    2015-06-24

    The effect of divalent substitution on the crystal structure and magnetic properties of BiFeO{sub 3} has been investigated using X-ray diffraction and magnetic measurements technique. Single phase Bi{sub 0.8}A{sub 0.2}FeO{sub 3} (A= Sr, Ba) multiferroics have been synthesized by solid state reaction method. Rietveld analysis of the XRD patterns revealed that the prepared ceramics exhibit rhombohedral structure with space group R3c. M–H hysteresis loops were recorded at 5K revealed that Sr and Ba substitution transformed antiferromagnetic BiFeO3 into weak ferromagnetic. The enhanced magnetization with Sr and Ba addition is confirmed by the MT curve recorded at 1T. It is closely related to intrinsic structural distortion and modification of the antiparallel spin structure.

  15. Study of Bi-2212 phase doped Sn(Pb) by means of pat

    International Nuclear Information System (INIS)

    Ma Qingzhu; Huang Xiaoqian; Xiong Xiaotao

    1997-01-01

    Investigation on the effect of Sn/Pb-doped Bi-2212 superconductors has been carried out by the simultaneous measurements of the spectra of positron annihilation lifetime and positron Doppler broadening, together with X-ray diffraction. The results of samples with different doping level show the occupation of Sn atoms on Bi sites. At weak doping level, Sn doping results in a enhancement of cooperation between layers and increment of superconducting transition temperature. At the strong doping level, Sn atoms occupy the sites of Cu-O layers, and at the same time, the other nonsuperconducting phases appear, which results in a decline of the superconducting transition temperature

  16. Measurements of neutron-induced fission cross sections of Pb and Bi at intermediate energies

    International Nuclear Information System (INIS)

    Ryzhov, Igor; Tutin, Gennady; Eismont, Vilen; Mitryukhin, Andrey; Oplavin, Valery; Soloviev, Sergey; Conde, Henri; Olsson, Nils; Renberg, Per-Ulf

    2002-01-01

    Neutron-induced fission cross sections of nat Pb and 209 Bi have been measured relative to the 238 U(n.f) cross section at energies 96 MeV for lead and 133 MeV for bismuth. The measurements were performed at the quasi-mono-energetic neutron beam facility of The Svedberg Laboratory in Uppsala using Frisch-gridded ionization chamber. The results obtained are compared with other experimental data. The present state of the Bi standard recommended by IAEA is discussed. (author)

  17. The inhomogeneities of (Pb,Bi)2223 superconducting tapes and their detection

    International Nuclear Information System (INIS)

    Leeuwen, S. van

    1999-05-01

    This thesis consists of two parts: first, the inhomogeneities that were observed in high temperature superconducting (Pb,Bi)2223 tapes were studied followed by the design of two rigs which were built to detect them. These investigations concentrated on (Pb,Bi)2223 phase high temperature superconducting tapes. Superconductors and their applications were briefly evaluated. It was found that high temperature superconductors have unique properties which cannot be duplicated by their counterparts. However, it was noted that there are significant improvements to be made before they can be commercially viable. An investigation was carried out into the variation of core density within cross sections and along lengths of (Pb,Bi)2223 tapes during fabrication. It was observed that rolling and thermal treatment brought about a non-uniform core density in both these aspects of tile tape. This was followed by an investigation into the effect of core density on the formation of the (Pb,Bi)2223 phase. It was shown that a high core density formed the (Pb,Bi)2223 phase at a slower rate than a lower core density under the thermal treatment. A high core density and a slow heating rate produced smaller 2212 grains at the end of the incubation period. Smaller 2212 grains were thought to be linked to the faster formation of the (Pb,B1)2223 phase. The highest Jc was from a high core density tape which had the smaller 2212 grains at the end of incubation period. Smaller 2212 grains were thought to aid a more homogeneous conversion to the (Pb,Bi)2223 phase. Alloy-sheathed (Pb,Bi)2223 superconducting tapes were produced in order to fabricate a more homogeneous core density. It was found that the alloy sheath (with an addition of 15% wt Ag in the precursor powder) changed the characteristics of the core in several ways: the formation of the (Pb,Bi)2223 phase was homogeneous across the thickness of the core, a smaller 2212 grain size was formed at the end of the incubation period and a higher

  18. The chemical fate of 212Bi-DOTA formed by β- decay of 212Pb(DOTA)2-

    International Nuclear Information System (INIS)

    Mirzadeh, S.; Kumar, K.; Gansow, O.A.

    1993-01-01

    The increasing use of inert metal complexes in radioimmunotherapy prompted us to explore the potential use of 212 Pb chelates. Herein, we report a study of the chemical fate of the 212 Bi-DOTA complex formed by β - decay of 212 Pb(DOTA) 2- (H 4 DOTA = 1,4,7,10-tetraazacyclododecanetetraacetic acid). To assure that both parent and daughter complexes were thermally stable, kinetic studies were performed with 203 Pb(II) and 206 Bi(III) which showed that both lead and bismuth complexes with DOTA undergo chemical exchange only very slowly in aqueous solution at pH 4-10. To investigate whether the complex ion which results from decay of 212 Pb(DOTA) 2- was intact and also stable, solutions initially containing only this ion were analyzed for amounts of DOTA-complexed and uncomplexed 212 Bi after attaining transient equilibrium with 212 Bi. The fraction of 212 Bi radioactivity not complexed to DOTA, vide infra, was found to be 36±2%. This value represents the fraction of breakup of 212 Bi(DOTA) - formed from β - decay of the parent complex. By considering the various extranuclear processes responsible for kinetic and electronic excitation of the 212 Bi daughter, break-up of the 212 Bi-DOTA complex is ascribed to the internal conversion of γ-rays emitted by the excited 212 Bi nuclide. (orig.)

  19. Neutron spectrum effects on TRU recycling in Pb-Bi cooled fast reactor core

    International Nuclear Information System (INIS)

    Kim, Yong Nam; Kim, Jong Kyung; Park, Won Seok

    2003-01-01

    This study is intended to evaluate the dependency of TRU recycling characteristics on the neutron spectrum shift in a Pb-Bi cooled core. Considering two Pb-Bi cooled cores with the soft and the hard spectrum, respectively, various characteristics of the recycled core are carefully examined and compared with each other. Assuming very simplified fuel cycle management with the homogeneous and single region fuel loading, the burnup calculations are performed until the recycled core reached to the (quasi-) equilibrium state. The mechanism of TRU recycling toward the equilibrium is analyzed in terms of burnup reactivity and the isotopic compositions of TRU fuel. In the comparative analyses, the difference in the recycling behavior between the two cores is clarified. In addition, the basic safety characteristics of the recycled core are also discussed in terms of the Doppler coefficient, the coolant loss reactivity coefficient, and the effective delayed neutron fraction

  20. The dispersive optical model for n + [sup 208]Pb and n + [sup 209]Bi

    Energy Technology Data Exchange (ETDEWEB)

    Walter, R.L. (Dept. of Physics, Duke Univ., Durham, NC (United States) Triangle Univ. Nuclear Lab., Durham, NC (United States)); Weisel, G.J. (Dept. of Physics, Duke Univ., Durham, NC (United States) Triangle Univ. Nuclear Lab., Durham, NC (United States)); Das, R.K. (Dept. of Physics, Duke Univ., Durham, NC (United States) Triangle Univ. Nuclear Lab., Durham, NC (United States)); Tornow, W. (Dept. of Physics, Duke Univ., Durham, NC (United States) Triangle Univ. Nuclear Lab., Durham, NC (United States)); Howell, C.R. (Dept. of Physics, Duke Univ., Durham, NC (United States) Triangle Univ. Nuclear Lab., Durham, NC (United States))

    1993-06-01

    The dispersive optical model (DOM) provides a natural connection between the shell model potential for bound states and the optical model for nucleon scattering at positive energies. At TUNL we have developed DOMs for neutron scattering for ten nuclei between [sup 27]Al and [sup 209]Bi. In these studies we rely on TUNL measurements of differential cross-section ([sigma]([theta])) and analyzing power, as well as a wealth of [sigma]([theta]) and total cross section measurements from numerous other laboratories. In this paper we briefly outline the DOM method and the achievements in describing scattering data for n + [sup 208]Pb and n + [sup 209]Bi and single-particle bound-state data for neutrons in [sup 208]Pb. (orig.)

  1. Precise measurement of the densities of liquid Bi, Sn, Pb and Sb

    International Nuclear Information System (INIS)

    Wang Lianwen; Wang Qiang; Xian Aiping; Lu Kunquan

    2003-01-01

    The densities of liquid Bi, Sn, Pb and Sb have been precisely measured from the melting point up to about 1100 K using an improved Archimedean method. The densities at the melting point for liquid Bi, Sn, Pb and Sb are 10.042 x 10 3 , 6.983 x 10 3 , 10.635 x 10 3 and 6.454 x 10 3 kg m -3 , respectively. Comparisons between our data and those from the literature have been made and they show the present results to be more reliable. Rather than a linear fit for the temperature dependence of the density, a slight deviation from linearity in the temperature dependence of the densities has been observed

  2. Half-metallic antiferromagnetism in double perovskite BiPbCrCuO6

    International Nuclear Information System (INIS)

    Weng, Ke-Chuan; Wang, Y. K.

    2015-01-01

    The electronic structure and magnetic properties of BiPbCrCuO 6 double perovskite are investigated based on first-principles density functional calculations with generalized gradient approximation (GGA) and GGA incorporated with Coulomb correlation interaction U (GGA + U). The results suggest the half-metallic (HM) and antiferromagnetic (AFM) properties of BiPbCrCuO 6 double perovskite. The HM-AFM property of the double perovskite is caused by the double-exchange mechanism between neighboring Cr 5+ (t 2g 1 ↓) and Cu 2+ (t 2g 3 ↑t 2g 3 ↓e g 2 ↑e g ↓) via the intermediate O 2− (2s 2 2p 6 ) ion

  3. Ultrasonic studies of aluminium-substituted Bi(Pb)-2223 superconductors

    Science.gov (United States)

    Solunke, M. B.; Sharma, P. U.; Pandya, M. P.; Lakhani, V. K.; Modi, K. B.; Venugopal Reddy, P.; Shah, S. S.

    2005-09-01

    The compositional dependence of elastic properties of Al^{3+}-substitu- ted Bi(Pb)-2223 superconducting system with the general formula Bi_{1.7-x}Al_xPb_{0.3}Sr_2Ca_2- Cu_3O_y (x = 0.0, 0.1, 0.2 and 0.3) have been studied by means of ultrasonic pulse transmission (UPT) technique at 1 MHz (300 K). The elastic moduli of the specimens are computed and corrected to zero porosity. The observed variation of elastic constants with aluminium substitution has been explained on the basis of the strength of interatomic bonding. The applicability of heterogeneous metal mixture rule for estimating elastic constants and transition temperature has been tested.

  4. Frozen magnetoresistance at magnetization reversal of granular Bi(Pb)-HTSC

    International Nuclear Information System (INIS)

    Sukhanov, A.A.; Omelchenko, V.I.

    2004-01-01

    The frozen magnetoresistance dependences of granular Bi(Pb)-HTSC samples on fields initiating a magnetic flux trapping and on magnetic reversal fields Rt(Hi, Hr) are investigated. It is found that the Rt (Hr) dependences are nonmonotonous. The frozen magnetoresistance decreases substantially after the first pulse Hr applied (Hr < Hi) but remains practically unchanged at subsequent remagnetization by magnetic pulses of alternating polarity and of the same amplitude. The effect of magnetic reversal on magnetoresistance anisotropy and the negative magnetoresistance phenomenon are studied. Is shown that the results obtained are inconsistent with the model of critical state for SC grains and the model of SC loops but are well described quantitatively by the proposed Bi(Pb)-HTSC model according to which the magnetic flux trapping occurs in normal grains with HTSC shells and the sample resistance is determined by weak link chains

  5. Synthesis and electrical properties of BaBiO 3 and high resistivity BaTiO 3BaBiO 3 ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Nitish [Oregon State Univ., Corvallis, OR (United States); Univ. of New South Wales, Sydney, NSW (Australia); Golledge, Stephen L. [Univ. of Oregon, Eugene, OR (United States); Cann, David P. [Oregon State Univ., Corvallis, OR (United States)

    2016-12-01

    Ceramics of the composition BaBiO3 (BB) were sintered in oxygen to obtain a single phase with monoclinic II2/mm symmetry as suggested by high-resolution X-ray diffraction. X-ray photoelectron spectroscopy confirmed the presence of bismuth in two valence states - 3+ and 5+. Optical spectroscopy showed presence of a direct bandgap at ~ 2.2eV and a possible indirect bandgap at ~ 0.9eV. This combined with determination of the activation energy for conduction of 0.25eV, as obtained from ac impedance spectroscopy, suggested that a polaron-mediated conduction mechanism was prevalent in BB. The BB ceramics were crushed, mixed with BaTiO3 (BT), and sintered to obtain BT–BB solid solutions. All the ceramics had tetragonal symmetry and exhibited a normal ferroelectric-like dielectric response. Using ac impedance and optical spectroscopy, it was shown that resistivity values of BT–BB were orders of magnitude higher than BT or BB alone, indicating a change in the fundamental defect equilibrium conditions. A shift in the site occupancy of Bi to the A-site is proposed to be the mechanism for the increased electrical resistivity.

  6. Apparent vanishing of ferroelectricity in nanostructured BiScO3PbTiO3

    OpenAIRE

    Amorín , H; Jiménez , R; Ricote , J; Hungría , T; Castro , A; Algueró , M

    2010-01-01

    Abstract Nanostructured ceramics of high-temperature piezoelectric 0.375BiScO 3 -0.625PbTiO 3 were prepared by spark plasma sintering of nanocrystalline powders obtained by mechanosynthesis. The macroscopic electrical properties were characterized on dense ceramics with decreasing average grain size down to 28 nm. Results indicate that the electric field is screened by the electrically insulating grain boundaries at the nanoscale, which needs to be considered when discussing size effects i...

  7. The 208Pb(7Li,6He)209Bi reaction at 52 MeV

    International Nuclear Information System (INIS)

    Zeller, A.F.; Weisser, D.C.; Ophel, T.R.; Hebbard, D.F.

    1979-11-01

    Single proton transfers to low lying levels in 209 Bi from the 208 Pb(7Li, 6 He) reaction at 52 MeV have been measured and spectroscopic factors derived from an EFR-DWBA analysis. Relative spectroscopic factors are in good agreement with light ion results and previous heavy ion work. Absolute spectroscopic factors were generally too large and the peaks of the angular distributions were out of phase with the DWBA calculations by 1 0 - 4 0

  8. Microstructure of laser floating zone (LFZ) textured (Bi,Pb)-Sr-Ca-Cu-O superconductor composites

    International Nuclear Information System (INIS)

    Fuente, G.F. de la; Ruiz, M.T.; Sotelo, A.; Larrea, A.; Navarro, R.

    1993-01-01

    Directionally solidified high temperature superconducting (Bi,Pb)-Sr-Ca-Cu-O pure ceramics and composites were obtained using a laser floating zone (LFZ) apparatus. The presence of secondary non-superconducting and metallic phases as well as their solidification habit have been analysed. The influence of the LFZ growth conditions and the precursor composition on the microstructure of the final products was studied using optical and electron microscopies. (orig.)

  9. Phase-shift analysis of neutron-209Bi scattering and its comparison to neutron-208Pb scattering

    International Nuclear Information System (INIS)

    Chen, Z.P.; Tornow, W.; Walter, R.L.

    1995-01-01

    Published n- 209 Bi elastic differential cross-section, analyzing power, and total cross-section data in the energy range from 1.5 to 14 MeV were analyzed via a phase-shift analysis in order to find out whether these data show similar, unexplained resonance structures as observed recently for n- 208 Pb scattering. Although the n- 209 Bi and n- 208 Pb data are very similar, some of the phase shifts are quite different for the two systems. Only one resonancelike structure was observed for n- 209 Bi scattering in the excitation energy range from 9 to 18 MeV compared to eleven in the n- 208 Pb system, implying that n- 209 Bi data are probably more suitable than the classical n- 208 Pb system for detailed mean-field analyses approached through dispersion-relation optical models

  10. Magnetoresistance and magnetothermopower properties of Bi/Ca/Co/O and Bi(Pb)/Ca/Co/O misfit layer cobaltites

    CERN Document Server

    Maignan, A; Hervieu, M; Michel, C; Pelloquin, D; Khomskii, D

    2003-01-01

    Two new compounds of the Bi/Ca/Co/O and Bi(Pb)/Ca/Co/O systems have been prepared. Their structure is built up from the intergrowth of four rock-salt-type layers and one [CoO sub 2 ] hexagonal layer. Both cobaltites exhibit large thermopower values (S sub 3 sub 0 sub 0 sub K approx 140 mu V K sup - sup 1), low resistivity values (rho sub 3 sub 0 sub 0 sub K = 40-60 m OMEGA cm) and small thermal conductivities (kappa sub 3 sub 0 sub 0 sub K approx 1 W K sup - sup 1 m sup - sup 1). Furthermore, these compounds exhibit a negative magnetoresistance, (MR = rho sub H - rho sub H sub sub 0 /rho sub H sub = sub 0), reaching, at 2.5 K, - 85% in 7 T for the Bi/Ca/Co/O misfit cobaltite. A large negative magnetothermopower is also found for these cobaltites in the same temperature range. A qualitative explanation of the observed behaviour is proposed.

  11. Synthesis and evaluation of tetraphosphonates labelled with 212Bi, 212Pb and 165Er

    International Nuclear Information System (INIS)

    Hassfjell, S.P.

    1997-08-01

    The main goal of this work has been to achieve a synthesis of radiolabelled phosphonates for the improvement of diagnostic and therapy of osteoblastic osteosarcoma and sclerotic bone metastases. 212 Bi-DOTMP is shown to be an in vivo stable bone seeking radiopharmaceutical with a potential for a α-particle therapy of the above mentioned diseases. It has biodistribution characteristics similar to 153 Sm-EDTMP, which is now formally approved in several countries, most recently in the US. 212 Pb-DOTMP is also a promising candidate having the advantage of increasing the effective half life of the α-emitter, although loss of some of the in vivo generated 212 Bi may be a problem. A generator has been developed for the production of the α-emitting radionuclide 212 Bi and its parent nuclide 212 Pb. The generator is based on the emanation of 220 Rn from ( 228 Th)barium stearate. The decay product of 220 Rn, 212 Pb deposits on the walls of a polyethylene bottle, and can be wasted off with distilled water. The generator shows no leakage of any long-lived parent nuclides, is easy to operate and has a high degree of radiation safety

  12. Study of the Neutron Deficient Pb and Bi Isotopes by Simultaneous Atomic- and Nuclear-Spectroscopy

    CERN Multimedia

    Kessler, T

    2002-01-01

    We propose to study systematically nuclear properties of the neutron deficient lead $^{183-189}$Pb, $^{191g}$Pb, $^{193g}$Pb and bismuth isotopes $^{188-200}$Bi by atomic spectroscopy with the ISOLDE resonance ionisation laser ion source (RILIS) combined with simultaneous nuclear spectroscopy at the detection set-up. The main focus is the determination of the mean square charge radii of $^{183-190}$Pb and $^{188-193}$Bi from which the influence of low-lying intruder states should become obvious. Also the nuclear spin and magnetic moments of ground-states and long-lived isomers will be determined unambiguously through evaluation of the hyperfine structure, and new isomers could be discovered. The decay properties of these nuclei can be measured by $\\alpha$-$\\gamma$ and $\\beta$-$\\gamma$ spectroscopy. With this data at hand, possible shape transitions around mid-shell at N$\\sim$104 will be studied. This data is crucial for the direct test of nuclear theory in the context of intruder state influence (e.g. energy ...

  13. Influence of conditions of preparation on quality of superconductors Bi(Pb)SrCaCuO with boron

    International Nuclear Information System (INIS)

    Sykorova, D.; Smrckova, O.; Ptrydes, D.; Vasek, P.

    1999-01-01

    The aim of this work was to verify influence of B 2 O 3 on formation of the phase Bi-2223 of samples with nominal composition Bi 1.8 (Pb 0.26 )Sr 2 Ca 2 Cu 3 O 8+x . Conditions of preparation of superconductors as well as their properties are described

  14. Spectroscopy of 214Bi and systematics of 210,212,214Pb(0+) long->β-210,212,214Bi(0-)

    International Nuclear Information System (INIS)

    Berant, Z.; Schuhmann, R.B.; Alburger, D.E.; Chou, W.T.; Gill, R.L.; Warburton, E.K.; Wesselborg, C.

    1991-01-01

    Experiments designed to provide more information on the spectroscopy of 214 Bi, and on 214 Pb(β - ) 214 Bi in particular, were undertaken because of interest in first-forbidden β decay in the lead region. The experiments consisted of γ-γ coincidences and angular correlations, conversion electron measurements, level lifetime determinations, and precision γ-ray energy measurements. The 352-keV level of 214 Bi was found to be a strong candidate (and the only candidate) for the 0 1 - state. Recent additions to the 214 Pb decay scheme are confirmed by γ-γ coincidence measurements. A careful evaluation of the 214 Bi level scheme is made with emphasis on separating experimentally based conclusions from speculations based on systematics and other ''weak'' arguments. Shell-model calculations of the spectroscopy of 210,212 Bi and 210,212 Pb(β - ) 210,212 Bi were performed using a modification of the Kuo-Herling realistic interaction. These calculations and a generalized seniority model provide a basis for an examination of the systematics of the A=210, 212, 214 spectroscopy and β decay. The generalized seniority model is found to be a quite good approximation which provides a quantitative understanding of the 214 Pb decay rates

  15. Dielectric properties of BaBi4Ti4O15 ceramics produced by cost-effective chemical method

    International Nuclear Information System (INIS)

    Chakrabarti, A.; Bera, J.; Sinha, T.P.

    2009-01-01

    BaBi 4 Ti 4 O 15 , an Aurivillius compound, was synthesized by a cost-effective soft chemical route. The precursor was prepared by precipitating Bi- and Ba-oxalates inside a TiO 2 powder suspension. A phase pure orthorhombic BaBi 4 Ti 4 O 15 was synthesized by heating the precursor powder at 1000 deg. C. The phase formation behavior was investigated using TG-DSC and XRD. Densification behavior of the powder and microstructure development in sintered pellet was examined. Temperature dependent dielectric study of the ceramic has been investigated in the temperature range 300-780 K and frequency range of 1 kHz-1 MHz. The broad dielectric constant peaks at temperature T m was frequency dependent. The dielectric relaxation rate follows the Vogel-Fulcher relation with activation energy=0.2639 eV, relaxation frequency=4.95x10 21 Hz, and freezing temperature=620 K. All these parameters indicate that BaBi 4 Ti 4 O 15 is a relaxor ferroelectric.

  16. Multiferroic properties of BiFeO3/BaTiO3 multilayered thin films

    International Nuclear Information System (INIS)

    Sharma, Savita; Tomar, Monika; Kumar, Ashok; Puri, Nitin K.; Gupta, Vinay

    2014-01-01

    Multilayered structures of multiferroic BiFeO 3 (BFO) and ferroelectric BaTiO 3 (BTO) have been fabricated using pulsed laser deposition (PLD). Ferromagnetic and ferroelectric properties of the multilayered system (BFO/BTO) have been investigated. It could be inferred that the magnetization increases with the incorporation of BTO buffer layer, which indicates a coupling between the ferroelectric and ferromagnetic orders. Vibrating sample magnetometer (VSM) measurements performed on the prepared multiferroic samples show that the magnetization is significantly increased (M s =56.88 emu/cm 3 ) for the multilayer system with more number of layers (four) keeping the total thickness of the multilayered system constant (350 nm) meanwhile maintaining the sufficiently enhanced ferroelectric properties (P r =29.68 µC/cm 2 )

  17. On the problems of Ba, Pb, Zn Ple{e ore deposit (Slovenia

    Directory of Open Access Journals (Sweden)

    Ivan Mlakar

    2003-12-01

    Full Text Available In this paper we present the years ago collected unpublished data on the Ple{e ore deposit which we completed also with some recent ones. They all speak against the offered interpretation of the geologic structure (Dozet, 1999, and especially against the Skythianage of this Ba, Pb and Zn deposit.We showed that the two large concordant barite bodies of syngenegtic origin are associated with an exactly determined horizon within the Carboniferous beds, that they were formed almost certainly in relation with the Asturian orogenic phase, and that theyoccur by chance in the hanging wall contact with the Skythian dolomite along a thrust plane. During Tertiary the epigenetic remobilization brought the ore substance from Paleozoic rocks into the mentioned dolomite. In one of the carefully investigated geochemictraverses the remobilization distance for Pb and Hg is 70 meters, and for Ba greater than 100 meters.For the existence of the PleŠe barite-bearing formation as conceived by Dozet (1999 there are no infallible proofs.

  18. Bi-Abundance Ionisation Structure of the Wolf-Rayet Planetary Nebula PB 8

    Science.gov (United States)

    Danehkar, A.

    2018-01-01

    The planetary nebula PB 8 around a [WN/WC]-hybrid central star is one of planetary nebulae with moderate abundance discrepancy factors (ADFs 2-3), which could be an indication of a tiny fraction of metal-rich inclusions embedded in the nebula (bi-abundance). In this work, we have constructed photoionisation models to reproduce the optical and infrared observations of the planetary nebula PB 8 using a non-LTE stellar model atmosphere ionising source. A chemically homogeneous model initially used cannot predict the optical recombination lines. However, a bi-abundance model provides a better fit to most of the observed optical recombination lines from N and O ions. The metal-rich inclusions in the bi-abundance model occupy 5.6% of the total volume of the nebula, and are roughly 1.7 times cooler and denser than the mean values of the surrounding nebula. The N/H and O/H abundance ratios in the metal-rich inclusions are 1.0 and 1.7 dex larger than the diffuse warm nebula, respectively. To reproduce the Spitzer spectral energy distribution of PB 8, dust grains with a dust-to-gas ratio of 0.01 (by mass) were also included. It is found that the presence of metal-rich inclusions can explain the heavy element optical recombination lines, while a dual-dust chemistry with different grain species and discrete grain sizes likely produces the infrared continuum of this planetary nebula. This study demonstrates that the bi-abundance hypothesis, which was examined in a few planetary nebulae with large abundance discrepancies (ADFs > 10), could also be applied to those typical planetary nebulae with moderate abundance discrepancies.

  19. Specific heat (1-330K), magnetic susceptiblity and Meissner effect Bi-(Pb)-Sr-Ca-Cu-O samples

    International Nuclear Information System (INIS)

    Junod, A.; Eckert, D.; Triscone, G.; Brunner, O.; Muller, J.; Zhao, Z.

    1989-01-01

    Five samples in the Bi 2 - y Pb y Sr 2 CaCu 2 O 8 + x system selected for their sharp diamagnetic transitions are characterized with particular emphasis on the specific heat. The behavior of the magnetic susceptibility upon doping with holes (Pb) is similar to that of the La 1 - y Sr y CuO 4 system

  20. Chemical solution deposited BaPbO3 buffer layers for lead zirconate titanate ferroelectric films

    International Nuclear Information System (INIS)

    Tseng, T.-K.; Wu, J.-M.

    2005-01-01

    Conductive perovskite BaPbO 3 (BPO) films have been prepared successfully by chemical solution deposition method through spin-coating on Pt/Ti/SiO 2 /Si substrates. The choice of baking temperature is a key factor on the development of conducting BPO perovskite phase. When the baking temperature is higher than 350 deg. C, the BPO films contain a high content of BaCO 3 phase after annealing at temperatures higher than 500 deg. C. If the baking temperature is chosen lower than 300 deg. C, such as 200 deg. C, the annealed BPO films consist mostly of perovskite with only traces of BaCO 3 . Choosing 200 deg. C as the baking temperature, the BPO films developed single perovskite phase at temperatures as low as 550 deg. C. The perovskite BPO phase is stable in the range of 550-650 deg. C and the measured sheet resistance of the BPO films is about 2-3 Ω/square. The perovskite BPO film as a buffer layer provides improvement in electric properties of lead zirconate titanate films

  1. 1D chain formation by coadsorption of Pb and Bi on Cu(001): Determination using low energy electron diffraction

    Science.gov (United States)

    Kabiruzzaman, Md; Ahmed, Rezwan; Nakagawa, Takeshi; Mizuno, Seigi

    2017-10-01

    Coadsorption of two heavy metals, Pb and Bi, on Cu(001) at room temperature has been studied using low energy electron diffraction (LEED). c(4 × 4), c(2 × 2), and c(9√{ 2}×√{ 2}) phases are obtained at different coverages; here, we have determined the best-fit structure of c(4 × 4) phase. This structure can be described as a 1D substitutional chain arrangement of Pb and Bi atoms between the Cu rows along the [110] direction. The unit cell in the two-dimensional (2D) surface consists of one Bi atom, two Pb atoms, and four Cu atoms with one vacancy at the center. The optimal structure parameters demonstrate that Bi atoms are located at fourfold-hollow sites and that Pb atoms are laterally displaced by 0.78 Å from the fourfold-hollow site toward the vacancy. The reasons for the formation of the c(4 × 4) structure upon deposition of Pb and Bi on Cu(001) are discussed in comparison with a similar structure formed by the individual adsorption of Pb on the same substrate.

  2. Potential laboratory health hazard of /sup 210/Pb and a simple procedure for separation of /sup 210/Pb from the daughters /sup 210/Bi and /sup 210/Po

    Energy Technology Data Exchange (ETDEWEB)

    Pounds, J G [Arkansas Univ., Little Rock (USA). Medical Center; Blakemore, W M [The National Center for Toxicological Research, Department of Health and Human Services, Food and Drug Administration, Jefferson, AR, USA

    1981-12-01

    Lead 210 (Radium D) is a naturally occurring radionuclide which is frequently used in toxicological studies due to its long half-life. The use of /sup 210/Pb in tracer studies poses two problems. First /sup 210/Pb, along with its daughters /sup 210/Bi and /sup 210/Po, presents a significant health hazard to laboratory personnel. Second, the presence of the daughter products may interfere with the detection of /sup 210/Pb, particularly by techniques which discriminate poorly between different radioactive emissions, e.g. autoradiography. The potential laboratory health hazards of /sup 210/Pb and its daughters are briefly reviewed and a simple dithiozone extraction procedure which allows quantitative separation of /sup 210/Pb from the daughters /sup 210/Po and /sup 210/Bi is described. The purified /sup 210/Pb may then be utilized to reduce the health hazard from the daughter products and to construct calibration curves for the quantitation of /sup 210/Pb in the presence of /sup 210/Bi and /sup 210/Po by liquid scintillation counting.

  3. Soft x-ray photoemission spectroscopy of the Ba atomic layer deposition on the ceramic multiferroic BiFeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Benemanskaya, G.V., E-mail: galina.benemanskaya@mail.ioffe.ru [Ioffe Institute, Politekhnicheskaya str. 26, St. Petersburg, 194021 (Russian Federation); Dementev, P.A.; Lapushkin, M.N. [Ioffe Institute, Politekhnicheskaya str. 26, St. Petersburg, 194021 (Russian Federation); Timoshnev, S.N. [St Petersburg Academic University, Khlopina str.8/3, St. Petersburg, 194021 (Russian Federation); Senkovskiy, B. [Helmholts-Zentrum Berlin, Elektronenspeicherring BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin (Germany)

    2017-04-01

    Highlights: • Ba/BiFeO{sub 3} interface was studied by X-ray synchrotron- photoemission spectroscopy. • Ba adsorption is found to modify the Bi 4f, O 1s and Fe 2p core level spectra. • Ba induced charge transfer causes increasing in Bi-valency and O-ionicity. • Ba adsorption results in increasing the amount of Fe{sup 2+} ions in the surface region. - Abstract: Electronic structure of the ceramic multiferroic BiFeO{sub 3} and the Ba/BiFeO{sub 3} nanointerface is investigated in situ in an ultrahigh vacuum by synchrotron-based photoemission spectroscopy with the excited photon energy from 120 eV to 900 eV. The Bi 4f, O 1s, Fe 2p, and Ba 5p core-levels spectra are studied. The Ba atomic layer deposition is found to induce a significant change in spectra that is originated from the charge transfer between Ba adatoms and Bi, O surface atoms with increasing the Bi-valency and O-ionicity. The Fe 2p{sub 3/2} core level spectrum for the clean BiFeO{sub 3} is shown to contain both the Fe{sup 2+} and Fe{sup 3+} ion components with the atomic ratio of Fe{sup 2+}/Fe{sup 3+} ∼1. The Ba adsorption is found to increase the ratio up to ∼1.5. This new effect is clearly caused by recharge between Fe{sup 3+} ↔ Fe{sup 2+} ions with increasing the amount of Fe{sup 2+} ions.

  4. Formation of layered microstructure in the Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O superconductors

    International Nuclear Information System (INIS)

    Jin, S.; Kammlott, G.W.; Tiefel, T.H.; Chen, S.K.

    1992-01-01

    The layered grain microstructure is essential for overcoming the weak link problem and ensuring high transport critical currents in the cuprate superconductors. In this paper we discuss the processing and the mechanisms for layer information in Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O. In melt-processed Y-Ba-Cu-O, sympathetic nucleation on previously nucleated YBa 2 Cu 3 O 7-δ plates during solidification appears to be dominant mechanism for the formation of parallel plate-shaped grains. In the Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O ribbons, the interface reaction between the superconductor layer and the silvers substrate seems to be the main mechanism for the c-axis texturing of the layered grains. The drastically different critical current behavior in the c-axis textured Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O ribbons is discussed in terms of possible differences in the nature of the twist and tilt grain boundaries. (orig.)

  5. Preparation of (Bi, Pb)-2223/Ag tapes by high temperature sintering and post-annealing process

    DEFF Research Database (Denmark)

    Hua, L.; Grivel, Jean-Claude; Andersen, L.G.

    2002-01-01

    A novel heat treatment process was developed to fabricate (Bi, Pb)-2223/Ag tapes with high critical current density (J(c)). The process can be divided into two parts: reformation and post-annealing. Tapes were first heated to the maximum temperature (830-860 degreesC) followed by slow cooling...... (reformation). Then, tape, were annealed between 760 and 820 degreesC (post-annealing). Reformation is expected to produce a large amount of liquid phase which may heat microcracks, decrease porosity, and improve grain growth. However, since the sintering temperature is beyond the Bi-2223 single-phase region......-energy synchrotron XRD and SEM/EDX. Some process parameters e.g. sintering temperature. cooling rate. and post-annealing time were optimised. (C) 2002 Elsevier Science B.V. All rights reserved....

  6. A novel greenish yellow-orange red Ba3Y4O9:Bi(3+),Eu(3+) phosphor with efficient energy transfer for UV-LEDs.

    Science.gov (United States)

    Li, Kai; Lian, Hongzhou; Shang, Mengmeng; Lin, Jun

    2015-12-21

    A series of novel color-tunable Ba3Y4O9:Bi(3+),Eu(3+) phosphors were prepared for the first time via the high-temperature solid-state reaction route. The effect of Bi(3+) concentration on the emission intensity of Ba3Y4O9:Bi(3+) was investigated. The emission spectra of the Ba3Y4O9:Bi(3+),Eu(3+) phosphors present both a greenish yellow band of Bi(3+) emission centered at 523 nm, and many characteristic emission lines of Eu(3+), derived from the allowed (3)P1-(1)S0 transition of the Bi(3+) ion and the (5)D0-(7)FJ transition of the Eu(3+) ion, respectively. The energy transfer phenomenon from Bi(3+) to Eu(3+) ions is observed under UV excitation in Bi(3+), Eu(3+) co-doped Ba3Y4O9 phosphors, and their transfer mechanism is demonstrated to be a resonant type via dipole-quadrupole interaction. The critical distance between Bi(3+) and Eu(3+) for the energy transfer effect was calculated via the concentration quenching and spectral overlap methods. Results show that color tuning from greenish yellow to orange red can be realized by adjusting the mole ratio of Bi(3+) and Eu(3+) concentrations based on the principle of energy transfer. Moreover, temperature-dependent PL properties, CIE chromaticity coordinates and quantum yields of Ba3Y4O9:Bi(3+),Eu(3+) phosphors were also supplied. It is illustrated that the as-prepared Ba3Y4O9:Bi(3+),Eu(3+) phosphors can be potential candidates for color-tunable phosphors applied in UV-pumped LEDs.

  7. Synthesis and crystal structure of Bi6.4Pb0.6P2O15.2

    International Nuclear Information System (INIS)

    Arumugam, N.; Lynch, V.; Steinfink, H.

    2007-01-01

    Bi 6.4 Pb 0.6 P 2 O 15.2 is a polymorph of structures with the general stoichiometry Bi 6+x M 1-x P 2 O 15+y . However, unlike previously published structures that consist of layers formed by edge sharing OBi 4 tetrahedra bridged by PO 4 and TO 6 (T=transition metal) tetrahedra and octahedra the title compound's structure is more complex. It is monoclinic, C2, a=19.4698(4) A, b=11.3692(3) A, c=16.3809(5) A, β=101.167(1) o , Z=10. Single-crystal X-ray diffraction data were refined by least squares on F 2 converging to R 1 =0.0387, wR 2 =0.0836 for 7023 intensities. The crystal twins by mirror reflection across (001) as the twin plane and twin component 1 equals 0.74(1). Oxygen ions are in tetrahedral coordination to four metal ions and the O(BiPb) 4 units share corners to form layers that are part of the three-dimensional framework. Eight oxygen ions form a cube around the two crystallographically independent Pb ions. Pb-O bond lengths vary from 2.265(14) to 2.869(14) A. Pairs of such cubes share an edge to form a Pb 3 O 20 unit. The two oxygen ions from the unshared edges are part of irregular Bi polyhedra. Other oxygen ions of Bi polyhedra are part only of O(BiPb) 4 units, and some oxygen ions of the polyhedra are also part of PO 4 tetrahedra. One, two, three and or four PO 4 moieties are connected to the Bi polyhedra. Bi-O bond lengths ≤3.1 A vary from 2.090(12) to 3.07(3) A. The articulations of Pb cubes, Bi polyhedra and PO 4 tetrahedra link into the three-dimensional structure. - Graphical abstract: View of the structure of Bi 6.4 Pb 0.6 P 2 O 15.2 parallel to the b-axis

  8. Coordination chemistry of the 212Pb/212Bi nuclear transformation: Alpha-emitting radiopharmaceuticals

    International Nuclear Information System (INIS)

    Parks, N.J.; Harris, W.R.; Keen, C.L.; Cooper, S.R.

    1992-07-01

    Subdivisions of this project are: (a) the synthesis of prototypical thiolate and dithiocarbamate based hexacoordinate complexes, (b) radiochemical engineering for generation of no-carrier-added lead and bismuth radioelements, (c) the first isolation of bismuth-binding proteins from in vivo studies with cyclotron produced 205/206 Bi tracer, and (d) initial development of transport mechanisms for the intracellular radiobiological study of alpha emitting bismuth, and (e) the initiation of chemical equilibrium studies and biochemical pathways with cyclotron-produced, no-carrier-added, 203 Pb (T 1/2 = 51 hr)

  9. Coordination chemistry of the sup 212 Pb/ sup 212 Bi nuclear transformation: Alpha-emitting radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Parks, N.J.; Harris, W.R.; Keen, C.L.; Cooper, S.R.

    1992-07-01

    Subdivisions of this project are: (a) the synthesis of prototypical thiolate and dithiocarbamate based hexacoordinate complexes, (b) radiochemical engineering for generation of no-carrier-added lead and bismuth radioelements, (c) the first isolation of bismuth-binding proteins from in vivo studies with cyclotron produced {sup 205/206}Bi tracer, and (d) initial development of transport mechanisms for the intracellular radiobiological study of alpha emitting bismuth, and (e) the initiation of chemical equilibrium studies and biochemical pathways with cyclotron-produced, no-carrier-added, {sup 203}Pb (T{sub 1/2} = 51 hr).

  10. Structure of the displacement field of substitutionally dissolved Bi in Pb

    International Nuclear Information System (INIS)

    Seitz, E.

    1975-03-01

    In order to describe measurements of the coherent diffuse scattering of neutrons from Pb-Bi within the single defect approximation, Schumacher (1969) introduced a model in which the displacement field of the host lattice caused by a given Bismuth atom has trigonal symmetry. In an attempt to decide which model for the displacement field is correct, new measurements over an extended range were carried out with an improved resolution, using the D7 diffractometer at the High Flux Reactor in Grenoble. Taking the different resolutions into account, agreement between the present and previous data is good, both as to absolute intensity and scattering pattern. (orig./HPoe) [de

  11. AC losses in (Bi,Pb) 2Sr 2Ca 2Cu 3O x tapes

    Science.gov (United States)

    D'Anna, G.; Indenbom, M. V.; André, M.-O.; Benoit, W.; Grivel, J.-C.; Hensel, B.; Flükiger, R.

    1994-05-01

    A double peak structure is observed in the AC losses of (Bi,Pb) 2Sr 2Ca 2Cu 3O x silver-sheathed tapes using a torsion-pendulum oscillator. The low-temperature peak is associated to the intragrain flux expulsion, while the high-temperature peak results from a macroscopic current path around the whole sample due to a well-coupled fraction of the grains. The flux pinning by the dislocations forming small-angle grain boundaries is suggested to control the transport current.

  12. Excellent corrosion resistance of 18Cr-20Ni-5Si steel in liquid Pb-Bi

    International Nuclear Information System (INIS)

    Kurata, Y.; Futakawa, M.

    2004-01-01

    The corrosion properties of three austenitic steels with different Si contents were studied under oxygen-saturated liquid Pb-Bi condition for 3000 h. The three austenitic steels did not exhibit appreciable dissolution of Ni and Cr at 450 deg. C. At 550 deg. C, the thick ferrite layer produced by dissolution of Ni and Cr was found in JPCA and 316SS with low Si contents while the protective oxide film composed of Si and O was formed on 18Cr-20Ni-5Si steel and prevented dissolution of Ni and Cr

  13. Fission threshold determination of 209Bi and sup(204,206,207,208)Pb by electrofission

    International Nuclear Information System (INIS)

    Tuerck, D.

    1975-01-01

    At the Darmstadt electron linear accelerator the cross sections for the electrofission of 209 Bi were measured for electron energies between 24 and 70 MeV, for the separated lead isotopes sup(204,206,207,208)Pb between 38 and 50 MeV. For the determination of the fission thresholds the cross sections were examined by the virtuel photon method using calculations in first Born approximation for the point nucleus with Coulomb wave functions. The analytic functions fitting the fission probability were based on level densities after the Fermi-gas-model. (orig./WL) [de

  14. Influence of PbBi environment on the low-cycle fatigue behavior of SNS target container materials

    International Nuclear Information System (INIS)

    Kalkhof, D.; Grosse, M.

    2003-01-01

    The low-cycle fatigue (LCF) behavior of the stainless steel 316L and the 10.5Cr-steel Manet-II was investigated at 260 deg. C in air and in stagnant lead-bismuth (PbBi). At low-strain levels, the fatigue lives for 316L in PbBi and air were comparable. At total strain amplitudes of 0.50% and higher a weak influence of PbBi was observed. In contrast to 316L, the results of LCF tests for Manet-II in PbBi showed a significant reduction of lifetime for all applied strain amplitudes. In the worst case the cycle number to crack initiation was reduced by a factor of ∼7 compared with the comparable test in air. For the low-strain amplitude of 0.30%, fatigue tests conducted at a frequency of 0.1 Hz had shorter fatigue lives than at a frequency of 1.0 Hz. For Manet-II the crack propagation in PbBi was much faster than in air, and failure immediate followed the formation of the first macroscopic crack

  15. Pb5Bi24Se41: A new member of the homologous series forming topological insulator heterostructures

    International Nuclear Information System (INIS)

    Segawa, Kouji; Taskin, A.A.; Ando, Yoichi

    2015-01-01

    We have synthesized Pb 5 Bi 24 Se 41 , which is a new member of the (PbSe) 5 (Bi 2 Se 3 ) 3m homologous series with m=4. This series of compounds consist of alternating layers of the topological insulator Bi 2 Se 3 and the ordinary insulator PbSe. Such a naturally-formed heterostructure has recently been elucidated to give rise to peculiar quasi-two-dimensional topological states throughout the bulk, and the discovery of Pb 5 Bi 24 Se 41 expands the tunability of the topological states in this interesting homologous series. The trend in the resistivity anisotropy in this homologous series suggests an important role of hybridization of the topological states in the out-of-plane transport. - Graphical abstract: X-ray diffraction profiles taken on cleaved surfaces of single-crystal samples of the (PbSe) 5 (Bi 2 Se 3 ) 3m homologous series with various m values up to 4, which realizes topological insulator heterostructures. Schematic crystal structure of the new phase, m=4, is also shown. - Highlights: • We have synthesized a new member of the homologous series related to topological insulators. • In this compound, a heterostructure of topological and ordinary insulators naturally forms. • Resistivity anisotropy suggests an important role of hybridization of the topological states. • This compound expands the tunability of the topological states via chemical means

  16. Structural, dielectric and magnetic studies of Ba and Nb codoped BiFeO{sub 3} multiferroics

    Energy Technology Data Exchange (ETDEWEB)

    Jangra, Sandhaya, E-mail: sndh17@gmail.com; Sanghi, Sujata; Agarwal, Ashish; Kaswan, Kavita; Rangi, Manisha; Singh, Ompal [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar, Haryana-125001 (India)

    2016-05-23

    Polycrystalline materials with composition Bi{sub 0.8}Ba{sub 0.2}Fe{sub 1-x}Nb{sub x}O{sub 3} (x= 0.07, 0.10) were prepared via solid state reaction method. Preliminary analysis of structure was performed by XRD technique and confirmed formation of single phase crystalline materials. Rietveld refinement reveled that these materials have rhombohedral phase with R3c space group. Dielectric constant increased with temperature and Nb concentration. Ba and Nb co-doping suppress the spiral spin structure and produce net magnetization.

  17. Synthesis, crystal structure, and magnetic properties of quaternary iron selenides: Ba{sub 2}FePnSe{sub 5} (Pn=Sb, Bi)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian; Greenfield, Joshua T.; Kovnir, Kirill

    2016-10-15

    Two new barium iron pnictide–selenides, Ba{sub 2}FeSbSe{sub 5} and Ba{sub 2}FeBiSe{sub 5}, were synthesized by a high-temperature solid-state route and their crystal structures were determined using single crystal X-ray diffraction. Both compounds are isomorphic to the high pressure phase Ba{sub 3}FeS{sub 5} and crystallize in the orthorhombic space group Pnma (No. 62) with cell parameters of a=12.603(2)/12.619(2) Å, b=9.106(1)/9.183(1) Å, c=9.145(1)/9.123(1) Å and Z=4 for Ba{sub 2}FeSbSe{sub 5} and Ba{sub 2}FeBiSe{sub 5}, respectively. According to differential scanning calorimetry, Ba{sub 2}FePnSe{sub 5} compounds exhibit high thermal stability and melt congruently at 1055(5) K (Pn=Sb) and 1105(5) K (Pn=Bi). Magnetic characterizations reveal strong antiferromagnetic nearest-neighbor interactions in both compounds resulting in an antiferromagnetic ordering at 58(1) K for Ba{sub 2}FeSbSe{sub 5} and 79(2) K for Ba{sub 2}FeBiSe{sub 5}. The magnetic interactions between Fe{sup 3+} centers, which are at least 6 Å apart from each other, are mediated by superexchange interactions. - Graphical abstract: In Ba{sub 2}FeSbSe{sub 5} and Ba{sub 2}FeBiSe{sub 5} the magnetic interactions between Fe{sup 3+} centers, which are at least 6 Å apart from each other, are mediated by superexchange interactions. - Highlights: • New compounds Ba{sub 2}FeSbSe{sub 5} and Ba{sub 2}FeBiSe{sub 5} have been synthesized. • The crystal structure was determined by single crystal X-ray diffraction. • Both compounds melt congruently at temperatures above 1000 K. • Ba{sub 2}FeSbSe{sub 5} and Ba{sub 2}FeBiSe{sub 5} exhibit AFM ordering at 58 K (Sb) and 70 K (Bi). • Magnetic exchange between Fe{sup 3+} is mediated by either Se–Sb(Bi)–Se or Se–Ba–Se bridges.

  18. Magnetoelectric properties of Pb free Bi2FeTiO6: A theoretical investigation

    Science.gov (United States)

    Patra, Lokanath; Ravindran, P.

    2018-05-01

    The structural, electronic, magnetic and ferroelectric properties of Pb free double perovskite multiferroic Bi2FeTiO6 are investigated using density functional theory within the general gradient approximation (GGA) method. Our structural optimization using total energy calculations for different potential structures show a minimum energy for a non-centrosymmetric rhombohedral structure with R3c space group. Bi2FeTiO6 is found to be an antiferromagnetic insulator with C-type magnetic ordering with bandgap value of 0.3 eV. The calculated magnetic moment of 3.52 μB at Fe site shows the high spin arrangement of 3d electrons which is also confirmed by our orbital projected density of states analysis. We have analyzed the characteristics of bonding present between the constituents of Bi2FeTiO6 with the help of calculated partial density of states and Born effective charges. The ground state of the nearest centrosymmetric structure is found to be a G-type antiferromagnet with half metallicity showing that by the application of external electric field we can not only get a polarized state but also change the magnetic ordering and electronic structure in the present compound indicating strong magnetoelectric coupling. The cation sites the coexistence of Bi 6s lone pair (bring disproportionate charge distribution) and Ti4+ d0 ions which brings covalency produces off-center displacement and favors a non-centrosymmetric ground state and thus ferroelectricity. Our Berry phase calculation gives a polarization of 48 µCcm-2 for Bi2FeTiO6.

  19. Phase equilibria and homogeneity range of the high temperature superconducting compound (Bi,Pb)2+xSr2Ca2Cu3O10+δ

    International Nuclear Information System (INIS)

    Kaesche, S.

    1995-01-01

    For the superconducting cuprates (Bi,Pb) 2+x Sr 2 Ca 2 Cu 3 O 10+y phase equilibria, the homogeneity region, and the phase formation has been studied in the temperture range 800 to 890 C. Sintered samples were prepared by a solid state reaction starting from Bi 2 O 3 , PbO, CuO and carbonates CaCO 3 and SrCO 3 in a three-stage calcination process. For the phase identification polarization microscopy, X-ray diffraction and susceptibility measurements have been applied. Multi-phase regions were determined in the cross section of the quasi-ternary system (Bi,Pb) 2 O 3 -SrO-CaO-CuO with constant Bi/(Bi+Pb) ratio 0.84 taking into account the 2223-phase. The homogeneity region was determined as function of Sr, Ca, Bi and Pb concentration. Its maximum size was found at 850 C

  20. Magnetization and critical currents of Bi-Sr-Ca-Cu-O and Ba2YCu3O7 superconductors

    International Nuclear Information System (INIS)

    Gyorgy, E.M.; van Dover, R.B.; Jin, S.; Sherwood, R.C.; Schneemeyer, L.F.; Tiefel, T.H.; Waszczak, J.V.

    1988-01-01

    We have measured the critical currrent density J/sub c/ as a function of temperature for a Bi-Sr-Ca-Cu-O sample containing a substantial fraction of a phase with T/sub c/≅110 K and for a Ba 2 YCu 3 O 7 sample (TT/sub c/≅92 K). The behavior of J/sub c/ was deduced from magnetization measurements. For both samples the magnetization at fixed temperature and field decayed logarithmically with time. The values of J/sub c/ so derived, allowing for the decay to occur, went to zero for temperatures above 35 K for the Bi-Sr-Ca-Cu-O ceramic and to zero above 70 K for the Ba 2 YCu 3 O 7 sample. These values are substantially lower than those deduced from dynamic M-H loops

  1. Alkaline earth lead and tin compounds Ae2Pb, Ae2Sn, Ae = Ca, Sr, Ba, as thermoelectric materials

    Directory of Open Access Journals (Sweden)

    David Parker and David J Singh

    2013-01-01

    Full Text Available We present a detailed theoretical study of three alkaline earth compounds Ca2Pb, Sr2Pb and Ba2Pb, which have undergone little previous study, calculating electronic band structures and Boltzmann transport and bulk moduli using density functional theory. We also study the corresponding tin compounds Ca2Sn, Sr2Sn and Ba2Sn. We find that these are all narrow band gap semiconductors with an electronic structure favorable for thermoelectric performance, with substantial thermopowers for the lead compounds at temperature ranges from 300 to 800 K. For the lead compounds, we further find very low calculated bulk moduli—roughly half of the values for the lead chalcogenides, suggestive of soft phonons and hence low lattice thermal conductivity. All these facts indicate that these materials merit experimental investigation as potential high performance thermoelectrics. We find good potential for thermoelectric performance in the environmentally friendly stannide materials, particularly at high temperature.

  2. Alkaline earth lead and tin compounds Ae2Pb, Ae2Sn, Ae = Ca, Sr, Ba, as thermoelectric materials

    Science.gov (United States)

    Parker, David; Singh, David J

    2013-01-01

    We present a detailed theoretical study of three alkaline earth compounds Ca2Pb, Sr2Pb and Ba2Pb, which have undergone little previous study, calculating electronic band structures and Boltzmann transport and bulk moduli using density functional theory. We also study the corresponding tin compounds Ca2Sn, Sr2Sn and Ba2Sn. We find that these are all narrow band gap semiconductors with an electronic structure favorable for thermoelectric performance, with substantial thermopowers for the lead compounds at temperature ranges from 300 to 800 K. For the lead compounds, we further find very low calculated bulk moduli—roughly half of the values for the lead chalcogenides, suggestive of soft phonons and hence low lattice thermal conductivity. All these facts indicate that these materials merit experimental investigation as potential high performance thermoelectrics. We find good potential for thermoelectric performance in the environmentally friendly stannide materials, particularly at high temperature. PMID:27877610

  3. The crystal structure of kudriavite, (Cd,Pb)Bi2S4

    DEFF Research Database (Denmark)

    Balic Zunic, Tonci; Makovicky, Emil

    2007-01-01

    The crystal structure of kudriavite, (Cd,Pb)Bi2S4, a new mineral species, was solved from single-crystal X-ray-diffraction data and refi ned to R = 4.9% (4.3% for a model with split mixed-cation sites). Lattice parameters are a 13.095(1), b 4.0032(3), c 14.711(1) Å, 115.59(1)°, V 695.6(1) Å3....... The structure is equivalent to that of synthetic CdBi2S4, space group C2/m, Z = 4, and represents a pavonite homologue, N = 3. It is built of three-octahedron-thick columns of (311)PbS-like slabs combined by "unitcell twinning" in a quasi-mirror-glide succession. The slabs, which are intrinsically of the same...... topology, differ in the coordination state of bordering cations because of the relative positions of the adjacent layers. In the slabs of type I (the "non-accreting" slab common to all pavonite homologues), the central columns of octahedra are fl anked by half-octahedral (square-pyramidal) coordinations...

  4. Enhancement of critical currents in bulk and Ag-sheathed Bi(Pb)-2223 superconductors

    International Nuclear Information System (INIS)

    Brauer, D.J.; Eujen, R.; Hudepohl, J.

    1991-01-01

    This paper reports on the superconducting properties of the Bi(Pb)-2223 phase that have been optimized. Prolonged annealing of coarse powder raised j c in bulk samples to as high as 1100 Acm -2 at 77 K. the temperature dependence was studied between 96 and 4.2 K whereby j c rose gradually from 120 to 2100 Acm -2 . T c dropped from 107 K to 64 K in magnetic fields up to 4 T but decreased by only 1 K/T in higher fields. A tape prepared by rolling and subsequent annealing of Ag tubes containing Bi(Pb)-2223 powder exhibited a j c of 1700 Acm -2 at 77 K and 11000 Acm -2 at 4.2 K. The latter j c dropped to 3000 Acm -2 in a magnetic field of 0.25 t, but it was still 1200 Acm -2 in a 10 T field. A tape fabricated by pressing a drawn and annealed wire proved to be less sensitive to low magnetic fields

  5. Synthesis, structure and superconductivity in Ba1-xKxBiO3

    International Nuclear Information System (INIS)

    Hinks, D.G.

    1989-01-01

    Ba 1-x K x BiO 3 (with x = 0.4) has the highest T c (30 K) of any copperless compound. The superconducting transition temperature of this material is expected to be at the limit of conventional electron-phonon coupling. Since this material is much simpler than the copper containing high-T c superconductors (it is cubic in its superconducting state and only sp electrons are involved in the transport properties), it should be much easier to unravel the nature of the superconducting pairing mechanism in this system. Understanding this system may help explain superconductivity in the more complex copper-oxide materials. In this paper, the authors report on the development of a synthesis method which allows the preparation of stoichiometric, single-phase materials with x between 0.0 and 0.5. The structural phase diagram was determined using powder neutron diffraction as a function of both composition and temperature. Superconductivity only occurs in the cubic perovskite phase which is stable for x larger than 0.3. At a x = 0.3 composition the material undergoes a semiconductor to metal transition with a maximum value for T c . As the K content is further increased, T c is reduced

  6. Synthesis and refinement of ferroelectric ceramic BaBi4Ti4O15 (BBT) using Rietveld Methods

    International Nuclear Information System (INIS)

    Silva, P.M.O.; Sales, A.J.M.; Carneiro, J.C.S.; Sancho, E.O.; Sales, J.C.; Sombra, A.S.B.

    2012-01-01

    The lead zirconate titanate (PZT) has potential application in nonvolatile ferroelectric memory and capacitors, however this material is linked to environmental pollution. In order to remedy this problem, we propose the synthesis of the compound, BaBi 4 TI 4 O 15 (BBT) because of similarity to PZT. The phase of the BBT has been prepared by the method of solid state. Reagents (BaCO 3 , Bi 2 O 3 and TiO 2 ) were ground for 6 hours at 360 rpm in a planetary ball mill and suffered high energy heat treatment for 2 hours at temperatures of 850, 900, 950 and 1000 ° C. The calcined powder was characterized by X-ray diffraction (XRD) and refined by the program DBWSTools 2.3 Beta based on the Rietveld method. The results obtained confirmed the refinement of the single-phase with tetragonal structure BaBi 4 TI 4 O 15 for all samples. The sample calcined at 950 °C presented the best densification (7.508 g/cm³). (author)

  7. Study of the structure, dielectric and ferroelectric behavior of BaBi4+δTi4O15 ceramics

    Science.gov (United States)

    Khokhar, Anita; Goyal, Parveen K.; Thakur, O. P.; Sreenivas, K.

    2016-05-01

    The structure and ferroelectric properties of excess bismuth doped barium bismuth titanate BaBi4+δTi4O15 (δ = 2 - 10 wt.%)) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material with a change in the orthorhombic distortion with varying excess of bismuth content. There is no change in the phase transition temperature (Tm) while the relaxor behaviour has been modified significantly with excess of bismuth doping. Saturated hysteresis loops with high remnant polarization (Pr ~ 12.5 µC/cm2), low coercive fields (Ec ~ 26 kV/cm) are measured and a high piezoelectric coefficient (d33 ~ 29 pC/N) is achieved in poled BaBi4Ti4O15 ceramics prepared with up to 8 wt.% of excess bismuth oxide. The improvement in the ferroelectric properties with increase in the excess bismuth content in BaBi4Ti4O15 ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of excess bismuth.

  8. Heavy ion coulomb excitation and gamma decay studies of the one and two phonon giant dipole resonances in 208Pb and 209Bi

    International Nuclear Information System (INIS)

    Mueller, P.E.; Beene, J.R.; Bertrand, F.E.; Halbert, M.L.; Olive, D.H.; Varner, R.L.; Sherrill, B.; Thoennessen, M.; Lautridou, P.; Lefevre, F.; Marques, M.; Matulewicz, T.; Mittig, W.; Ostendorf, R.; Roussel-Chomaz, P.; Schutz, Y.; Pol, J. van; Wilschut, H.W.; Diaz, J.; Ferrero, J.L.; Marin, A.

    1994-01-01

    Projectile - phonon coincidences were measured for the scattering of an 80 MeV/nucleon 64 Zn beam from 208 Pb and 209 Bi targets at the GANIL heavy ion accelerator facility. Projectile-like particles between 0.5 and 4.5 relative to the incident beam direction were detected in the SPEG energy loss spectrometer where their momentum, charge, and mass were determined. Photons were detected in the BaF 2 scintillation detector array TAPS. Light charged particles produced in the reaction were detected in the KVI Forward Wall. The analysis of the data acquired in this experiment is focused on three different phenomena: (1) the two phonon giant dipole resonance, (2) time dependence of the decay of the one phonon giant dipole resonance, and (3) giant resonance strength in projectile nuclei. (orig.)

  9. Effect of Pb and Ag additions on electrical properties Bi2Sr2Ca2Cu3Ox superconductive ceramics

    International Nuclear Information System (INIS)

    Reddi, B.V.; Uskov, E.M.

    1990-01-01

    The influence of Pb and Ag additions on the electrical properties of Bi 2 Sr 2 Ca 2 Cu 3 O x superconducting ceramics has been studied by Hall method. It was found that the Pb additions has more influence on the sample characteristics than Ag. It was found, that Hall EMF at 77 K equal to zero in the samples having some residue resistance

  10. Structure and electrical properties of (1 − x) (Na0.5Bi0.5)0.94Ba0.06TiO3–x BiAlO3 lead-free piezoelectric ceramics

    International Nuclear Information System (INIS)

    Fu, Peng; Xu, Zhijun; Chu, Ruiqing; Wu, Xueyan; Li, Wei; Li, Xiaodong

    2013-01-01

    Highlights: ► (1 − x) BNBT6–x BA ceramics were prepared by solid-state reaction method. ► Electrical properties of BNBT6 ceramics are improved by the addition of BA. ► (1 − x) BNBT6 - x BA ceramics at x = 0.0225 have the best electrical properties. - Abstract: (1 − x) (Na 0.5 Bi 0.5 ) 0.94 Ba 0.06 TiO 3 –x BiAlO 3 ((1 − x) BNBT6–x BA) lead-free piezoelectric ceramics were synthesized by conventional solid-state processes. Effects of BiAlO 3 (BA) on the structure and electrical properties of (Na 0.5 Bi 0.5 ) 0.94 Ba 0.06 TiO 3 (BNBT6) ceramics were investigated. X-ray diffraction (XRD) data shows that (1 − x) BNBT6–x BA ceramics form the pure perovskite phases, and the ceramics have the morphotropic phase boundary (MPB) when x r = 42.5 μC/cm 2 ), the highest piezoelectric coefficient (d 33 = 204 pC/N), the highest planar coupling factor (k p = 0.3292), the highest dielectric constant (ε r = 1687) and higher mechanical quality factor (Q m = 112)

  11. Effect of copper valence on the glass structure and crystallization behavior of Bi-Pb-Cu-O glasses

    International Nuclear Information System (INIS)

    Hu, Yi; Lin, U.-L.; Liu, N.-H.

    1997-01-01

    Bi 0.43 Pb 0.35 Cu 0.22 O y glasses with different Cu + contents were prepared by melting at different temperatures. The glass structure consists of [BiO 3 [ and [BiO 6 [ units and the ratio of [BiO 3 [/[BiO 6 [ increases with increasing Cu + content. The glass transition temperature, the first crystallization temperature peak, and the thermal stability of the glasses decreases with increasing Cu + content. The value of the activation energy, E a , varies as a function of the Cu + content. The crystallization mechanism in the glasses is closely related to the glass structure, which is mainly affected by the Cu + content. (orig.)

  12. Determining metal ion distributions using resonant scattering at very high-energy K-edges: Bi/Pb in Pb{sub 5}Bi{sub 6}Se{sub 14}

    Energy Technology Data Exchange (ETDEWEB)

    Yuegang, Zhang; Lee, P L; Shastri, S D; Deming, Shu [Argonne National Lab., IL (United States). XOR, Advanced Photon Source; Wilkinson, A P [Georgia Inst. of Tech., Atlanta (United States). School of Chemistry and Biochemistry; Duck-Young, Chung; Kanatzidis, M G [Michigan State Univ., East Lansing (United States). Dept. of Chemistry

    2005-06-01

    Powder diffraction data collected at {proportional_to} 86 keV, and just below both the Pb and the Bi K-edges, on an imaging plate detector using synchrotron radiation from the Advanced Photon Source have been used to examine the Pb/Bi distribution over the 11 crystallographically distinct sites in Pb{sub 5}Bi{sub 6}Se{sub 14} [space group P2{sub 1}/m, a=16.0096(2) Aa, b=4.20148(4) Aa, c=21.5689(3) Aa and {beta}=97.537(1){sup 0}]. The scattering factors needed for the analyses were determined both by Kramers- Kronig transformation of absorption spectra and by analyses of diffraction patterns from reference compounds. Even with the relatively low scattering contrast that is available at the K-edges, it was possible to determine the Pb/Bi distribution and probe the presence of cation site vacancies in the material. The current results indicate that resonant scattering measurements at high-energy K-edges are a viable, and perhaps preferable, route to site occupancies when absorption from the sample or sample environment/container is a major barrier to the acquisition of high-quality resonant scattering data at lower-energy edges.

  13. Conductivity and superconductivity of (Bi,Pb)-Sr-Ca-Cu-O

    International Nuclear Information System (INIS)

    Gazda, M.; Kusz, B.; Klimczuk, T.; Natali, R.; Stizza, S.

    2007-01-01

    The (Bi,Pb)-Sr-Ca-Cu-O glass-ceramics may be considered as disordered metal and superconductor. Depending on the heat treatment conditions the materials are either composed of the oval grains of the 2212 or 2201 phases embedded in the insulating matrix or they mainly contain the 2212 plate-like crystallites weakly connected one with another. The materials have large resistivity and usually large negative temperature coefficient of resistivity (TCR). The granular and disordered character of the materials is also reflected in their superconducting properties. Both the normal-state and superconducting properties correlate one with another. The glass-ceramic samples were obtained by annealing the amorphous solid at temperatures between 840 and 860 deg. C. The measurements of the temperature dependence of resistivity in annealed samples were carried out with the conventional four-terminal method in a temperature range from 3 to 300 K

  14. Evaluation of Two 300 MWe Fourth Generation Pb-Bi Reactor System Concepts

    International Nuclear Information System (INIS)

    Miller, Laurence F.; Khuram Khan, M.; Williams, Wesley; Mynatt, F.R.

    2002-01-01

    This paper describes the evaluation of two 300 MWe modular Pb-Bi cooled reactor system concepts that can be field assembled from components shipped on standard rail cars or on trucks. Thus, the largest components must be smaller than 12' x 12' x 80' (3.66 m x 3.66 m x 24.4 m) and should weigh no more than 80 tons. One of these systems utilizes a cylindrical two-loop containment vessel for the core and the other is a slab design. The fuel for both designs consists of standard-sized metallic IFR fuel in 17 x 17 square array assemblies with a pitch-to-diameter ratio of 1.15. The coolant outlet temperature is limited by current material technology, which is estimated to be 550 C. The primary coolant inlet temperature is selected to be 350 C. This is well above the melting temperature of Pb-Bi, and it is expected to be sufficiently high to limit transient-induced thermal stresses to acceptable values. Coolant flow rates through the core and external piping are below 1 m/s. The results from neutronics calculations include power distributions, reactivity coefficients, and fuel depletion, and results from heat transfer calculations include temperatures and flow rates at various locations in the primary and secondary systems. The neutronic design calculations are accomplished by using a discrete ordinate transport code and a cross section processing system developed at Oak Ridge National Laboratory. Two-dimensional flux distributions are obtained with the DOORS system, and ORIGEN-S, coupled with KENO, is used for time-dependent depletion calculations. The thermal-hydraulic design of the core consists of heat transfer and fluid flow calculation for an average channel. The inlet and outlet temperatures, along with the fuel centerline temperature, are determined in conjunction with core flow rates, pumping power, and total power output. This is accomplished by using a lumped parameter steady-state model with a spreadsheet and by using a one-dimensional time-dependent model

  15. Multineutron emission cross-sections of Pb-208 and Bi-209 for use in fusion technology

    International Nuclear Information System (INIS)

    Garg, S.

    1995-01-01

    Pb-208 and Bi-209 are considered as promising materials for fusion blankets because of their superior neutron multiplying characteristics. In this paper, emission cross-sections for neutrons, protons, alpha-particles and gamma-rays are investigated for these nuclides in the energy range 8-30 MeV using the framework of the multistep Hauser-Feshbach statistical theory combined with the Kalbach exciton model for the pre-equilibrium decay and the Brink - Axel model of the giant dipole resonance to account for the radiative capture competition. Appropriate optical model potential parameters are selected to evaluate the compound nucleus reaction cross-sections at different neutron incident energies. (n,n'), (n,2n), (n,3n), (n,4n) and the total production cross-sections for neutrons, protons, alpha-particles and gamma-rays are inferred by performing consistent calculations. (author). 22 refs, 3 figs

  16. Evaluation at the medium energy region for Pb-208 and Bi-209

    International Nuclear Information System (INIS)

    Fukahori, Tokio; Pearlstein, S.

    1991-01-01

    Medium energy nuclear data in the 1--1000 MeV range is necessary to accelerator applications which include spallation neutron sources for radioactive waste treatment and accelerator shielding design, medical applications which include isotopes production and radiation therapy, and space applications. For the design of fission and fusion reactors, the nuclear data file for neutrons below 20 MeV is available and well evaluated. Evaluated nuclear data for protons and data in the medium energy region, however, have not been prepared completely. Evaluation in the medium energy region was performed using the theoretical calculation code ALICE-P or experimental data. In this paper, the evaluation of neutron and proton induced nuclear data for Pb-208 and Bi-209 has been performed using ALICE-P, empirical calculations and new systematics for the fission cross section. The evaluated data are compiled for possible inclusion in the ENDF/B-VI High Energy File. 204 refs., 51 figs., 9 tabs

  17. High-pressure anisotropic distortion of Pb3Bi2S6

    DEFF Research Database (Denmark)

    Olsen, Lars Arnskov; Balic Zunic, Tonci; Makovicky, Emil

    2008-01-01

    The compound Pb3Bi2S6 is investigated by X-ray diffraction on single crystals in a diamond-anvil cell between 0.0001 and 10.5 GPa. It undergoes a first-order phase transition at hydrostatic pressure between 3.7 and 4.9 Gpa. The space group symmetry changes from Bbmm to Pbnm, and the unit......-cell volume decreases by 4%. The transition is strongly anisotropic, with a contraction along one of the crystal axes by 16% and expansion along another one by 14%. This is a piezoplastic phase transition, a displacive pressure-induced phase transition with systematic shearing of atomic planes and a migration...

  18. Out-of-pile chemical compatibility of Pb-Bi eutectic alloy with graphite

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, A.K.; Bhagat, R.K.; Jarvis, T.; Majumdar, S. [Radiometallurgy Div., Bhabha Atomic Research Centre, Mumbai (India); Laik, A.; Kale, G.B. [Material Science Div., Bhabha Atomic Research Centre, Mumbai (India); Kamath, H.S. [Nuclear Fuels Group, Bhabha Atomic Research Centre, Mumbai (India)

    2006-06-15

    Lead Bismuth eutectic alloy (Pb: 55.5 wt.%, Bi: 44.5 wt.%) is a potential candidate coolant material for high-temperature reactors because of its low melting point (124 C), high thermal conductivity, heat capacity, and better neutronic properties. Out-of-pile chemical compatibility studies of this coolant with graphite (coolant channel) have been carried out by isothermal annealing of the liquid alloy in a graphite crucible at 800, 900, 1000, and 1100 C for times ranging from 100 h to 1000 h. Formation of a reaction layer is observed. The growth rate of the reaction layer follows a parabolic law. Reaction layer thicknesses of 61.3 {mu}m and 121 {mu}m are estimated from the growth rate vs. time relation after 1 year and 5 years respectively. The growth of the reaction layer is diffusion-controlled and the activation energy of the reaction is estimated to be 100 KJ/mol. (orig.)

  19. Out-of-pile chemical compatibility of Pb-Bi eutectic alloy with graphite

    International Nuclear Information System (INIS)

    Sengupta, A.K.; Bhagat, R.K.; Jarvis, T.; Majumdar, S.; Laik, A.; Kale, G.B.; Kamath, H.S.

    2006-01-01

    Lead Bismuth eutectic alloy (Pb: 55.5 wt.%, Bi: 44.5 wt.%) is a potential candidate coolant material for high-temperature reactors because of its low melting point (124 C), high thermal conductivity, heat capacity, and better neutronic properties. Out-of-pile chemical compatibility studies of this coolant with graphite (coolant channel) have been carried out by isothermal annealing of the liquid alloy in a graphite crucible at 800, 900, 1000, and 1100 C for times ranging from 100 h to 1000 h. Formation of a reaction layer is observed. The growth rate of the reaction layer follows a parabolic law. Reaction layer thicknesses of 61.3 μm and 121 μm are estimated from the growth rate vs. time relation after 1 year and 5 years respectively. The growth of the reaction layer is diffusion-controlled and the activation energy of the reaction is estimated to be 100 KJ/mol. (orig.)

  20. Growth of nucleation sites on Pb-doped Bi2Sr2Ca1Cu2O8+δ

    International Nuclear Information System (INIS)

    Finnemore, D.K.; Xu, M.; Kouzoudis, D.; Bloomer, T.; Kramer, M.J.; McKernan, S.; Balachandran, U.; Haldar, P.

    1996-01-01

    In the growth of Bi 2 Sr 2 Ca 2 Cu 3 O 10+δ from mixed powders of Pb-doped Bi 2 Sr 2 Ca 1 Cu 2 O 8+δ and other oxides, it has been discovered that a dense array of hillocks or mesas grow at the interface between a Ag overlay and Pb-doped Bi 2 Sr 2 Ca 1 Cu 2 O 8+δ grains during the ramp up to the reaction temperature. As viewed in an environmental scanning electron microscope, the Ag coated grains develop a texture that looks like open-quote open-quote chicken pox close-quote close-quote growing on the grains at about 700 degree C. These hillocks are about 100 nm across and are spaced at about 500 to 1000 nm. If there is no Ag, this texture does not develop. Preliminary measurements indicate that the hillocks are a recrystallization of (Bi,Pb) 2 Sr 2 Ca 1 Cu 2 O 8+δ , and are definitely not a Pb rich phase. copyright 1996 American Institute of Physics

  1. Nano-Channels Early Formation Investigation on Stainless Steel 316Ti after Immersion in Molten Pb-Bi

    Directory of Open Access Journals (Sweden)

    Abu Khalid Rivai

    2017-04-01

    Full Text Available Pb-Bi (lead-bismuth eutectic-LBE is a coolant of one of main candidates for the future nuclear reactor in the world (Generation IV reactors i.e. LFR (Lead alloy-cooled Fast Reactor, and also a spallation target material for ADS (Accelerator Driven Transmutation System. However, the development of fuel cladding and structural materials in LBE environment, especially at high temperature, is a critical issue for the deployment of LFR and ADS. This is because of the corrosive characteristic of LBE to metals as constituent materials of fuel cladding and structural of the reactors. In this study, corrosion test of a high-chromium austenitic steel i.e. SS316Ti in liquid Pb-Bi at 550ºC has been carried out for about 300 hours. The characterization using SEM-EDS (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscope showed that an iron oxide as the outer layer and a chromium oxide as the inner layer on the surface of the specimen were formed which protected the steel specimen from corrosion and dissolution attack of Pb-Bi. However, small amount of Pb-Bi could penetrate into the iron oxide layer through ultra-thin channels. Atomic Force Microscopy (AFM was employed to investigate the phenomena of the channels formation. The results of the nano-scale investigation showed clearly the formation of the channels.

  2. Mineralogical data on angelaite, Cu2AgPbBiS4, from the Los Manantiales District, Chubut, Argentina

    DEFF Research Database (Denmark)

    Topa, D.; Paar, W.H.; Putz, H.

    2010-01-01

    Angelaite, ideally Cu2AgPbBiS4, occurs as a hypogene mineral in polymetallic ores at the Ángela groups of veins in the mining district of Los Manantiales, in the province of Chubut, Argentina. The new mineral species is predominantly associated with pyrite, sphalerite, chalcopyrite, hematite...

  3. Fluctuation Induced Conductivity Studies of 100 MeV Oxygen Ion Irradiated Pb Doped Bi-2223 Superconductors

    NARCIS (Netherlands)

    Banerjee, Tamalika; Kumar, Ravi; Kanjilal, D.; Ramasamy, S.

    2000-01-01

    We report on 100 MeV oxygen ion irradiation in Pb doped Bi-2223 superconductors. Resistivity measurements reveal that both grains as well as the grain boundaries are affected by such irradiation. An analysis of the excess conductivity has been made within the framework of Aslamazov-Larkin (AL) and

  4. L-shell ionization studies of Pb and Bi with α particles

    International Nuclear Information System (INIS)

    Dhal, B.B.; Nandi, T.; Padhi, H.C.

    1994-01-01

    Ionization cross sections for the L subshells of Pb and Bi by α-particle bombardment (2.2--8.2 MeV) have been determined from the experimental data and the currently available radiative transition probabilities, fluorescence yields, and Coster-Kronig factors. The measured ionization cross sections and their ratios are compared with the results of ECPSSR calculations [ECPSSR denotes perturbed-stationary-state (PSS) theory with energy-loss (E), Coulomb deflection (C), and relativistic (R) corrections]. The measured individual cross sections for L 1 and L 2 subshells deviated in opposite directions from the theory, whereas their sum shows good agreement. The L 3 and total ionization cross sections obtained from the data also show good agreement with the ECPSSR theory. The ionization cross-section ratios σ L1 /σ L2 and σ L3 /σ L2 show large deviations from the ECPSSR theory. The experimental x-ray production cross-section ratios are found to be in better agreement with the theoretical results obtained from using ECPSSR ionization cross sections and the decay yield data of Xu and Xu [J. Phys. B 25, 695 (1992)] rather than those obtained from using the decay yield data of Krause [J. Phys. Chem. Ref. Data 8, 307 (1979)]. The x-ray production cross sections, however, are in better agreement with the theoretical results obtained from using the decay yield data of Krause. The measured centroid energy of the Lγ lines of Pb shows large deviations at high projectile energy, whereas for Bi large deviations are found at the low-energy region

  5. Study of the structure and ferroelectric behavior of BaBi{sub 4-x}La{sub x}Ti{sub 4}O{sub 15} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Khokhar, Anita, E-mail: mails4anita@gmail.com; Sreenivas, K. [Department of Physics & Astrophysics, University of Delhi, Delhi-110 007 (India); Goyal, Parveen K. [Department of Physics, ARSD College, University of Delhi, Dhaula Kuan, New Delhi-110 021 (India); Thakur, O. P. [Electroceramics Group, Solid State Physics Laboratory, Lucknow Road, Delhi 110 054 (India)

    2015-06-24

    The structure and ferroelectric properties of Lanthanum substituted barium bismuth titanate BaBi{sub 4-x}La{sub x}Ti{sub 4}O{sub 15} (0 ≤ x ≤ 0.5) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material. The distribution of lanthanum into the perovskite layers and (Bi{sub 2}O{sub 2}){sup 2+} layers of BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics have been revealed through Raman spectroscopy. At lower value of x, it is seen that La{sup 3+} ions prefer to substitute A-site Bi{sup 3+} ions in the perovskite layers while for higher x values, La{sup 3+} ions get incorporated into the (Bi{sub 2}O{sub 2}){sup 2+} layers. A critical La content of x ∼ 0.2 in BaBi{sub 4-x}La{sub x}Ti{sub 4}O{sub 15} is seen to exhibit a large remnant polarization (P{sub r}) with low coercive field (E{sub c}). The improvement in the ferroelectric properties of La substituted BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of lanthanum ion.

  6. SINTESIS SUPERKONDUKTOR SISTEM (Bi,PbSr(Y,CaCuO BERFASE 1212 DENGAN METODE PELELEHAN

    Directory of Open Access Journals (Sweden)

    M. Sumadiyasa

    2012-08-01

    Full Text Available Superconductors system BPSCCO 1212 phase have been synthesized by solid state reaction with melting methods. The schedules: calcining at 9000C during 10 h, making of pellet, melting at 10100C for 0.1 h, cooling (cooling rate 350C/h to 9800C, and sintering at 9800C during 5, 10, 20, and 30 h. From measurement of XRD, all of the sample has showed to be formed of  Bi-1212 phase. The highest volume fraction reach 91,23 % given by sample which is sintering at 9800C during 10 h. The spectrum pattern show reflection of its 00l extremely high intensity, showing the existence highly textured which as according to the typical behaviour for materials with the c-axis lying normal to the surface plane. The resistivity as function of temperature, that sample not yet shown the existence of Tc0, not yet had the superconducting properties at temperature above 77 K. The SEM shows morphology of surface, showing the existence of  the stacking of plate-like. Analyse EDX at some spots observation, show elements distribution of Bi, Pb, Sr, Y, Ca and Cu nearly homogenous, and its ratio of the spots on grain have been nearly the composition of 1212 phase.

  7. Theoretical investigation on thermoelectric properties of (Ca,Sr,Ba)Fe2(As/Bi)2 compounds under temperature

    Science.gov (United States)

    Jayalakshmi, D. S.; Sundareswari, M.; Viswanathan, E.; Das, Abhijeet

    2018-04-01

    The electrical conductivity, resistivity and Seebeck coefficient, Pauli magnetic susceptibility and power factor are computed under temperature (100 K - 800 K) in steps of 100 K for the theoretically designed compounds namely (Ca,Sr,Ba)Fe2Bi2 and their parent compounds namely (Ca,Sr,Ba)Fe2As2 by using Boltzmann transport theory interfaced to the Wien2k program. The Bulk modulus, electron phonon coupling constant, thermoelectric figure of merit (ZT) and transition temperature are calculated for the optimized anti ferromagnetic phase of the proposed compounds. The results are discussed for the novel compounds in view of their superconductivity existence and compared with their parent unconventional superconducting compounds.

  8. An X-ray fluorescence method for the determination of Ba, Sr, Mo and Bi in thorium oxide

    International Nuclear Information System (INIS)

    Dixit, R.M.; Deshpande, S.S.

    1988-01-01

    A simple and rapid X-ray fluorescence method for the determination of Ba, Sr, Mo and Bi in thoria is described. Thorium oxide samples are dry-mixed thoroughly with pure boric acid in the ratio of 9:1. One gram of mixture is pressed as a double layer over a primary boric acid pellet. The precision and accuracy of the method have been determined. The power limits of detection are found to be around 20 ppm for most analytes. (author). 5 tables

  9. Anomalous field dependence of the Sommerfeld coefficient in the isotropic (K,Ba)BiO3 superconductor

    International Nuclear Information System (INIS)

    Klein, T.; Marcenat, C.; Bouquet, F.; Junod, A.; Blanchard, S.; Marcus, J.

    2004-01-01

    We report on specific heat measurements in high quality (K,Ba)BiO 3 single crystals (T c ∼31.5 K). A well defined specific heat jump is clearly visible at T C p (H) in the entire investigated field range (up to 13 T). However, the corresponding T C p (H) exhibits an anomalous positive curvature and the amplitude of the jump rapidly decreases with field suggesting a non-linear increase of the Sommerfeld coefficient (γ(H)). This anomalous behaviour is confirmed by low temperature measurements which show that γ(H)∝H α with α∼0.65

  10. Thermal cycling properties of a lead-free positive temperature coefficient thermistor in the Ba0.97(Bi0.5Na0.5)0.03TiO3 system

    Science.gov (United States)

    Choi, Hyoung-Seuk; Choi, Soon-Mok; Choi, Duck-Kyun

    2016-01-01

    A Pb-free PTC (positive temperature coefficient thermistor) heater was developed in the Ba0.97(Bi0.5Na0.5)0.03TiO3 system especially for automotive part applications. The reliability was verified by using a thermal cycling test designed on the basis of the result from a quality function deployment (QFD) analysis. We compared the thermal cycling test results from the newly-developed Pb-free PTC heaters with the results from PTC heaters currently on the market, namely, PTC heaters containing Pb. Life prediction and stress-strength relationships were analyzed together with a thermal diffusivity evaluation. We discuss the potential failure mechanisms during the thermal cycling test, focusing on the fact that electrical degradation in PTC materials is closely related to mechanical degradation due to the internal stress in the materials that comes from repeated phase changes. Different grain size distributions on the sintered bulks were considered to a key factor for explaining the different results of the reliability tests between the new Pb-free PTC heaters developed in this study and the commercial PTC heaters containing Pb.

  11. Development of heat resistant Pb-free joints by TLPS process of Ag and Sn-Bi-Ag alloy powders

    Directory of Open Access Journals (Sweden)

    Ohnuma I.

    2012-01-01

    Full Text Available TLPS (Transient Liquid Phase Sintering process is a candidate method of heat-resistant bonding, which makes use of the reaction between low-melting temperature powder of Sn-Bi base alloys and reactive powder of Ag. During heat treatment above the melting temperature of a Sn-Bi base alloy, the molten Sn-Bi reacts rapidly with solid Ag particles, which results in the formation of heat-resistant intermetallic compound (IMC. In this study, the TLPS properties between Sn-17Bi-1Ag (at.% powder with its liquidus temperature of 200°C and pure Ag powder were investigated. During differential scanning calorimetry (DSC measurement, an exothermic reaction and an endothermic reaction occurred, which correspond to the formation of the e-Ag3Sn IMC phase and the melting of the Sn-17Bi-1Ag alloy, respectively. After the overall measurement, the obtained reactant consists of the Ag3Sn-IMC and Bi-rich phases, both of which start melting above 250°C, with a small amount of the residual Sn-Bi eutectic phase. These results suggest that the TLPS process can be applied for Pb-free heatresistant bonding.

  12. Developments of 207Pb, 208Pb and 209Bi target wheels in the synthesis of 107Ns, 108Hs and 109Mt

    International Nuclear Information System (INIS)

    Folger, H.; Hartmann, W.; Hessberger, F.P.; Hofmann, S.; Klemm, J.; Muenzenberg, G.; Ninov, V.; Schmidt, K.H.; Schoett, H.J.; Thalheimer, W.; Armbruster, P.

    1993-05-01

    The developments of 207 Pb, 208 Pb and 209 Bi target wheels and their applications in heavy-ion fusion reactions are reviewed. In both, fabrication and use, the centers of the evaporator or accelerator beams are focussed at wheel radii of 155 mm to specially shaped frames which generate very homogeneous target layers and very constant reaction and counting rates in the experiment. Target areas of up to ∼98% of a wheel's circumference of 974 mm can be provided. The preparation procedures for necessary C backings and protecting layers of C are described, and details are given for the developments of high-vacuum evaporations of 207 Pb, 208 Pb and 209 Bi with deposition yields of 35-55% from tantalum crucibles. The applications of the target wheels in heavy-ion fusion reactions with beams of 54 Cr and 58 Fe at energies near the Coulomb barrier and intensities of ∼10 12 particles/s are mentioned. The target parameters for the production runs of the new chemical elements 107 Ns, 108 Hs and 109 Mt are included. (orig.)

  13. Ab initio hybrid DFT calculations of BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Eglitis, Roberts I., E-mail: rieglitis@gmail.com

    2015-12-15

    Highlights: • Surface energies for AO{sub 3}-term (111) surfaces are larger than for Ti (Zr)-term surfaces. • A increase of Ti−O (Zr−O) bond covalency near the ABO{sub 3} (111) surface relative to the bulk is observed. • The ABO{sub 3} (111) surface energy is larger than the earlier calculated (001) surface energy. • Band gap for PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surfaces becomes smaller, but for BaTiO{sub 3} (111) larger with respect to the bulk . - Abstract: The results of ab initio calculations for polar BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surfaces using the CRYSTAL code are presented. By means of the hybrid B3LYP approach, the surface relaxation has been calculated for two possible B (B = Ti or Zr) or AO{sub 3} (A = Ba, Pb or Sr) BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surface terminations. According to performed B3LYP calculations, all atoms of the first surface layer, for both terminations, relax inwards. The only exception is a small outward relaxation of the PbO{sub 3}-terminated PbTiO{sub 3} (111) surface upper layer Pb atom. B3LYP calculated surface energies for BaO{sub 3}, PbO{sub 3}, SrO{sub 3} and PbO{sub 3}-terminated BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surfaces are considerably larger than the surface energies for Ti (Zr)-terminated (111) surfaces. Performed B3LYP calculations indicate a considerable increase of Ti−O (Zr−O) chemical bond covalency near the BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surface relative to the BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} bulk. Calculated band gaps at the Γ-point near the PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surfaces are reduced, but near BaTiO{sub 3} (111) surfaces increased, with respect to the BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} bulk band gap at the Γ-point values.

  14. Characterization of highly (110)- and (111)-oriented Pb(Zr,Ti)O3 films on BaPbO3 electrode using Ru conducting barrier

    International Nuclear Information System (INIS)

    Liang, C.-S.; Wu, J.-M.

    2005-01-01

    Highly non-(001)-oriented Pb(Zr,Ti)O 3 (PZT) films have been fabricated by rf-magnetron sputtering. The preferential (110)-oriented BaPbO 3 (BPO) deposited on Ru buffer layer induces the growth of (110)-oriented PZT film. With the aid of self-organized growth of PZT, the orientation of the film deposited on random-oriented BPO/Pt(111)/Ru(002) is (111)-preferred. The insertion of Pt layer between BPO and Ru changes the orientation of PZT from (110) to (111) and prevents the oxygen diffusion. These non-(001)-oriented PZT films possess more superior ferroelectric, fatigue, and retention properties than those of (001)-oriented PZT films

  15. Technologies for hydrogen production based on direct contact of gaseous hydrocarbons and evaporated water with Molten Pb or Pb-Bi

    International Nuclear Information System (INIS)

    Gulevich, A. V.; Martynov, P. N.; Gulevsky, V. A.; Ulyanov, V. V.

    2007-01-01

    Results of studies intended for the substantiation of a new energy-saving and safe technology for low cost hydrogen production have been presented. The technology's basis is direct mixing of water and (or) gaseous hydrocarbons with heavy liquid metal coolants (HLMC) Pb or Pb-Bi. Preliminary research has been done on thermal dynamics and kinetics of the processes taking place in the interaction of HLMC with hydrocarbon-containing gases. It has been shown as a result that water and gaseous hydrocarbons interact with molten Pb and Pb-Bi relatively quietly in chemical aspect (without ignition and explosions). Therefore, (and taking into account the thermal physics, physical and chemical properties of HLMC such as low pressure of saturated vapor of Pb and Pb- Bi in enhanced temperatures, their good heat conductivity and heat capacity, low viscosity, etc.) heat transfer is possible from the molten metal to water and hydrocarbons without heat transferring partitions (that is, by direct contact of the working media). Devices to implement this method of heating liquid and gaseous media provide essential advantages: - A simple design; - None heat-transferring surfaces subject to corrosion, contamination, thermal fatigue, vibration impacts; - A high effectiveness owing to a larger heat exchanging surface per volume unit; - A small hydraulic resistance. The possibility and effectiveness of heating various gaseous and liquid media in their direct contact with molten Pb and Pb-Bi has been substantiated convincingly by experimental results at IPPE. Besides, the following processes of hydrogen-containing media conversion have been proved feasible thereby. 1. Water decomposition into hydrogen and oxygen. The process can develop at temperatures of 400-1000 degree C. It is necessary to provide constant removal of oxygen from the reaction zone and maintain a minimum possible content of chemically active oxygen in the melt. 2. Pyrolytic decomposition of hydrocarbons into carbon and

  16. Band-gap tuning and magnetic properties of heterovalent ions (Ba, Sr and Ca) substituted BiFeO_3 nanoparticles

    International Nuclear Information System (INIS)

    Chauhan, Sunil; Kumar, Manoj; Katyal, S. C.

    2016-01-01

    A Comparative study of heterovalent Ba, Sr and Ca ions substitution on the structural, vibrational, optical and magnetic properties of BiFeO_3 nanoparticles was carried out. The distorted rhombohedral structure was confirmed from both X-ray diffraction and Raman spectroscopy techniques in pure BiFeO_3 and Bi_0_._8_5A_0_._1_5FeO_3 (A= Ba, Sr and Ca) samples. UV-Visible spectroscopy results show that the band-gap of BiFeO_3 nanoparticles can be tuned by heterovalent ions substitution from 2.12 eV for BiFeO_3 to 2.10, 2.06 and 2.03 eV for Ca, Sr and Ba substituted BiFeO_3 nanoparticles respectively. The magnetic measurements indicate enhancement in magnetization for heterovalent A"2"+ substituted BiFeO_3 samples and the magnetization increases with increase of ionic radius of the substituted ions.

  17. Synthesis and Microstructure Properties of (Bi,Pb2Sr2Ca1Cu2Oy Ceramic Superconductor

    Directory of Open Access Journals (Sweden)

    nurmalita .

    2015-11-01

    Full Text Available Properties of (Bi, Pb2Sr2Ca1Cu2Oy ceramic superconductors were prepared by the melt textured growth methods in order to investigate the effects of the slow cooling time on the microstructur.  Phase analyses of the samples by X-ray diffraction (XRD has been carried out to assess the effects of the slow cooling time. From XRD analyses, the addition to the sample of  the slow cooling time degrades formation of the high-Tc Bi-2212 phase. The possible reasons for the observed degradation in the microstructure properties due to the slow cooling time addition were discussed.

  18. Magnetoelectric and electric measurements of the (1-x)BiFeO{sub 3}–(x)Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3} solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bochenek, D., E-mail: dariusz.bochenek@us.edu.pl [University of Silesia, Faculty of Computer Science and Material Science, Institute of Technology and Mechatronics, 12, Żytnia St., 41–200, Sosnowiec (Poland); Niemiec, P. [University of Silesia, Faculty of Computer Science and Material Science, Institute of Technology and Mechatronics, 12, Żytnia St., 41–200, Sosnowiec (Poland); Guzdek, P. [Institute of Electron Technology Cracow Division, 39, Zabłocie St., Cracow, 30-701 (Poland); Wzorek, M. [Institute of Electron Technology, Al. Lotników 32/46, 02-668, Warsaw (Poland)

    2017-07-01

    In the paper ferro–electro–magnetic (1-x)BiFeO{sub 3}-(x)Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3} (BF-PFN) solid solutions were obtained (containing the percentage BF/PFN: 60/40 and 70/30). Individual components of the solid solution were prepared by follows methods: synthesizing a powder BF was performed by calcining the simple oxides (Bi{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}), and synthesizing a powder PFN was carried out by calcining a mixture of complex oxides (FeNbO{sub 4}, PbO). Compaction of synthesized and mixed BiFeO{sub 3}, PbFe{sub 1/2}Nb{sub 1/2}O{sub 3} powders was carried out by free sintering methods. X–ray, microstructure, dielectric, magnetic and magnetoelectric studies, DC electrical conductivity and electrical hysteresis loop were carried out. Magnetoelectric effect measurements performed at room temperature showed coupling between electric and magnetic subsystem of the BF–PFN solid solutions. - Highlights: • BF-PFN samples have a densely packed microstructure, with well crystallized grains. • Bi atoms possibly migrate from BF toward PFN component during sintering. • BF-PFN have a diffuse character of the ferroelectric–paraelectric phase transition. • Magnetoelectric coefficient (α{sub ME}) for BF-PFN is higher, than for pure BF. • The α{sub ME} for BF-PFN is about three times higher than for 0.75BiFeO{sub 3}–0.25BaTiO{sub 3}.

  19. A note on structural and dielectric properties of BiFeO3- PbTiO3 and BiFeO3- PbZrO3 composites

    International Nuclear Information System (INIS)

    Satpathy, S. K.; Mohanty, N. K.; Behera, A. K.; Behera, B.; Nayak, P.

    2015-01-01

    The composites of BiFeO 3 -PbTiO 3 (BF-PT) and BiFeO 3 -PbZrO 3 (BF-PZ) were prepared by mixed oxide method. Room temperature X-ray diffraction data confirms the rhombohedral and tetragonal crystal structure respectively. Dielectric constant of BF-PZ is found to give high value compared to BF-PT and hence, there is an increase value of ac conductivity for the former. Both the composites show negative temperature coefficient of resistance (NTCR) behavior. The activation energies of BF-PT and BF-PZ are found to be 0.35 eV and 0.53 eV respectively. The d 33 coefficients are found to be 2.0 and 2.1 pC/N for BF-PT and BF-PZ respectively

  20. Synthesis of the phase with T sub c =110 K in Bi(Pb)-Sr-Ca-Cu-O superconducting ceramics. Sintez fazy T sub c =110 K sverkhprovodyashchej keramiki sostava Bi(Pb)-Sr-Ca-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    Dubovitskij, A V; Makarov, E F; Makova, M K; Merzhanov, V A; Topnikov, V N [AN SSSR, Moscow (USSR). Inst. Khimicheskoj Fiziki

    1991-05-01

    Synthesis of 110 K single-phase bismuth ceramics (BiPb){sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub x} was conducted in narrow temperature and time range. Diffusion of bismuth ions is proposed to be the decisive factor of synthesis of bismuth ceramics. The diffusion depends on prehistory of basic burden preparation and on its dispersivity and homogeneity in particluar. Optimal time of synthesis for lead doped ceramics of 2223 composition, synthesized from initial nitrate components, is equal to 65 h at 850 deg C. The role of Pb{sup 2+} ions is probably reduced to decrease of diffusion mobility of Bi{sup 3+} ions over the bismuth sublattice. Ceramics doping with CdO and CdCl{sub 2} compounds instead of lead stabilizes superconductivity in bismuth ceramics, but with worth superconducting parameters.

  1. Magnetoelectric effect in (BiFeO3x–(BaTiO31-x solid solutions

    Directory of Open Access Journals (Sweden)

    Kowal Karol

    2015-03-01

    Full Text Available The aim of the present work was to study magnetoelectric effect (ME in (BiFeO3x-(BaTiO31-x solid solutions in terms of technological conditions applied in the samples fabrication process. The rapidly growing interest in these materials is caused by their multiferroic behaviour, i.e. coexistence of both electric and magnetic ordering. It creates possibility for many innovative applications, e.g. in steering the magnetic memory by electric field and vice versa. The investigated samples of various chemical compositions (i.e. x = 0.7, 0.8 and 0.9 were prepared by the solid-state sintering method under three sets of technological conditions differing in the applied temperature and soaking time. Measurements of the magnetoelectric voltage coefficient αME were performed using a dynamic lock-in technique. The highest value of αME was observed for 0.7BiFeO3-0.3BaTiO3 solid solution sintered at the highest temperature (T = 1153 K after initial electrical poling despite that the soaking time was reduced 10 times in this case.

  2. Fatigue and retention in ferroelectric Y-Ba-Cu-O/Pb-Zr-Ti-O/Y-Ba-Cu-O heterostructures

    Science.gov (United States)

    Ramesh, R.; Chan, W. K.; Wilkens, B.; Gilchrist, H.; Sands, T.; Tarascon, J. M.; Keramidas, V. G.; Fork, D. K.; Lee, J.; Safari, A.

    1992-09-01

    Fatigue and retention characteristics of ferroelectric lead zirconate titanate thin films grown with Y-Ba-Cu-O(YBCO) thin-film top and bottom electrodes are found to be far superior to those obtained with conventional Pt top electrodes. The heterostructures reported here have been grown in situ by pulsed laser deposition on yttria-stabilized ZrO2 buffer [100] Si and on [001] LaAlO3. Both the a- and c-axis orientations of the YBCO lattice have been used as electrodes. They were prepared using suitable changes in growth conditions.

  3. Creep Behavior of a Sn-Ag-Bi Pb-Free Solder

    Science.gov (United States)

    Vianco, Paul; Rejent, Jerome; Grazier, Mark; Kilgo, Alice

    2012-01-01

    Compression creep tests were performed on the ternary 91.84Sn-3.33Ag-4.83Bi (wt.%, abbreviated Sn-Ag-Bi) Pb-free alloy. The test temperatures were: −25 °C, 25 °C, 75 °C, 125 °C, and 160 °C (± 0.5 °C). Four loads were used at the two lowest temperatures and five at the higher temperatures. The specimens were tested in the as-fabricated condition or after having been subjected to one of two air aging conditions: 24 hours at either 125 °C or 150 °C. The strain-time curves exhibited frequent occurrences of negative creep and small-scale fluctuations, particularly at the slower strain rates, that were indicative of dynamic recrystallization (DRX) activity. The source of tertiary creep behavior at faster strain rates was likely to also be DRX rather than a damage accumulation mechanism. Overall, the strain-time curves did not display a consistent trend that could be directly attributed to the aging condition. The sinh law equation satisfactorily represented the minimum strain rate as a function of stress and temperature so as to investigate the deformation rate kinetics: dε/dtmin = Asinhn (ασ) exp (−ΔH/RT). The values of α, n, and ΔH were in the following ranges (±95% confidence interval): α, 0.010–0.015 (±0.005 1/MPa); n, 2.2–3.1 (±0.5); and ΔH, 54–66 (±8 kJ/mol). The rate kinetics analysis indicated that short-circuit diffusion was a contributing mechanism to dislocation motion during creep. The rate kinetics analysis also determined that a minimum creep rate trend could not be developed between the as-fabricated versus aged conditions. This study showed that the elevated temperature aging treatments introduced multiple changes to the Sn-Ag-Bi microstructure that did not result in a simple loss (“softening”) of its mechanical strength.

  4. Separation of 210 Pb, 210 Bi and 210 Po by ion exchange and their liquid scintillation standardization

    International Nuclear Information System (INIS)

    Rodriguez, L.; Jimenez, A.; Grau, A.

    1996-01-01

    We applied the CIEMAT/NIST method and alpha/beta discrimination to ''210 Pb samples in equilibrium with its daughters, by preparing homogeneous and gel samples. The stability of samples was tested in different available cocktails, HiSafe''tm II, HiSafe''tmIII, Ultima-Gold''tm, Ultima-Gold''tmXR, Ultima-Gold''tmAB, Insta-Gel and e Insta-Gel II. Also we analyzed the disequilibrium of the radioactive chain ''210Pb+''210Bi+''210Po, achieving and excellent agreement between the results of the spectrum unfolding method and the experimental values. (Author) 13 refs

  5. Separation of 210Pb, 210Bi and 210Po by ion exchange and their Iiquid scintillation standardization

    International Nuclear Information System (INIS)

    Rodriguez, L.; Jimenez, A.; Grau, A.

    1996-01-01

    We applied the CIEMAT/NIST method and alpha/beta discrimination to ''210Pb samples in equilibrium with its daughters, by preparing homogeneous and gel samples. The stability of samples was tested in different available cocktails, HiSafe''TM II, HiSafe''TM III, Ultima-Gold''TM, Ultima-Gold''TM XR, Ultima-Gold''TM AB, Insta-Gel''R and e Insta-Gel''R lI. Also we analyzed the disequilibrium of the radioactive chain 210Pb+210Bi+210Po, achieving an excellent agreement between the results of the spectrum unfolding method and the experimental values. (Author) 13 refs

  6. Enhancment of ferromagnetism in Ba and Er co-doped BiFeO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Naeimi, A.S., E-mail: naeimi.a.s@gmail.com [Department of Physics, Aliabad Katoul Branch, Islamic Azad University, Aliabad Katoul (Iran, Islamic Republic of); Dehghan, E.; Sanavi Khoshnoud, D. [Department of Physics, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of); Gholizadeh, A. [School of Physics, Damghan University (DU), Damghan (Iran, Islamic Republic of)

    2015-11-01

    Bi{sub 1−y−x}Ba{sub y}Er{sub x}FeO{sub 3} [BB{sub y}E{sub x}FO, (0.13≤y≤0.17, 0≤x≤0.2)] nanoparticles were successfully synthesized by a sol–gel method. The structural, microstructural and magnetic properties have been investigated, using X-ray diffraction, Raman scattering, field emission scanning electron microscopy (FE-SEM) and magnetometry measurements at room temperature. The refinement of X-ray diffraction pattern of BB{sub 0.15}E{sub 0}FO indicates a phase transition from rhombohedral (R3c) to tetragonal (P4mm) with increasing Ba content and a transition from the coexistence of rhombohedral–tetragonal phase to orthorhombic (Pbnm) in BB{sub 0.15}E{sub x}FO samples with increasing Er concentration. The Raman analysis confirms crystal phase transition in BB{sub 0.15}E{sub x}FO compounds. The FE-SEM and TEM analysis show that the average nanoparticle size is about 50–100 nm and it decreases with Er concentration. The remnant magnetisation of BB{sub 0.15}E{sub 0.1}FO sample (M{sub r}=0.98 emu/g) is approximately two times greater than compared to BB{sub 0.15}E{sub 0}FO (M{sub r}=0.51 emu/g) that may be attributed to the collapse of spin structure and modifying exchange interactions because of Er{sup +3} doping. This enhancement in magnetic properties at room temperature can play an important role for the practical applications. - Highlights: • Bi{sub 1−y−x}Ba{sub y}Er{sub x}FeO{sub 3} nanoparticles were successfully synthesized by a sol–gel route. • X-ray diffraction and Raman spectroscopy measurements confirmed a phase transition from rhombohedral–orthorhombic. • Considerable enhancement in magnetisation of BiFeO{sub 3} is obtained with Ba and Er co-doping.

  7. Determination of the neutron resonance parameters for 206Pb and of the thermal neutron capture cross section for 206Pb and 209Bi

    International Nuclear Information System (INIS)

    Borella, A.

    2005-01-01

    Chapter 1 describes the motivation of the measurements (accelerator driven systems, stellar nucleosynthesis, neutron induced reactions on 206 Pb), the present status of the neutron capture data for 206 Pb and 209 Bi and the structure of this work. In Chapter 2 the basic reaction theory underlying this work is described. The neutron induced reaction mechanism and formalism are explained. The parameterisation of the cross section in terms of R-matrix theory is discussed and we put particular emphasis on the statistical behaviour of the resonance parameters and the impact of the angular distribution of gamma rays following neutron capture. The relation between experimental observables and the resonance parameters is discussed together with general comments related to resonance shape analysis. Chapter 3 is focused on the determination of resonance parameters for 206 Pb. We performed high-resolution transmission and capture measurements at the Time-Of-Flight (TOF) facility GELINA of the IRMM at Geel (B) and determined the resonance parameters. For nuclei like 206 Pb, where the total width is dominated by Γ n , the capture area allows to determine G . Transmission measurements were carried out to determine Γ n , and the statistical factor g of resonances. Before performing a Resonance Shape Analysis (RSA) on the transmission and capture data, we verified the neutron flux and resolution at GELINA. We also compared the characteristics of GELINA with those of the n-TOF facility at CERN. A special emphasis is placed on the total energy detection technique using C 6 D 6 detectors. This technique was applied for the determination of the capture cross section. To reduce systematic bias effects on the capture cross section, the response of the detectors was determined by Monte Carlo simulations, which has been validated by experiments. Using these response functions the partial capture cross sections for individual resonances of 206 Pb have been deduced, by unfolding the

  8. Adaptive strain prompting a pseudo-morphotropic phase boundary in ferroelectric (1-x ) Na0.5Bi0.5TiO3-x BaTiO3

    Science.gov (United States)

    Datta, K.; Neder, R. B.; Richter, A.; Göbbels, M.; Neuefeind, J. C.; Mihailova, B.

    2018-05-01

    The understanding of the atomistic origin of the morphotropic phase boundary (MPB) occurring in composition-temperature phase diagrams of ferroelectric solid solutions is a key topic in material science because materials often exhibit anomalous properties at the MPB. Here we reveal mesoscopic-scale structural correlations for a leading Pb-free ferroelectric system, (1 -x ) Na0.5Bi0.5TiO3-x BaTiO3 (NBT-x BT ), by examining atomic pair distribution functions and Raman scattering data at ambient conditions. We demonstrate that the amplification of the piezoelectric properties of NBT-x BT at the MPB are predominantly driven by an easy switchability resulting from a progressive decoupling between strain and polarization as the Ba content increases from zero to the critical MPB composition. It was observed that as Ba content increases towards MPB, competing local correlations, such as A-site chemical order, antiferrodistortive correlations of correlated BO6 tilts, and antipolar Bi shifts, are reduced, which in turn renders favorable conditions for easy switching of local dipoles under external fields. In addition, the evolving characteristics of the atomic dynamics as a function of composition suggest that the local potential functions of the cations are not completely flat at the MPB. Altogether, our results reveal atomistic mechanisms responsible for the observed elevated MPB properties in the case of NBT-x BT which imply that the so-called MPB of NBT-x BT should not be categorized as originally introduced for Pb-containing solid solutions.

  9. Electronic structure of Pr doped into superconducting Bi-Pb-Sr-Ca-Cu-O ceramics

    International Nuclear Information System (INIS)

    Egorov, A.I.; Karazhanova, G.I.; Smirnov, Yu.P.; Sovestnov, A.E.; Tyunis, A.V.; Shaburov, V.A.

    1992-07-01

    The shift of K α 1 and K β 1 X-ray lines of Pr in HTS-ceramic Bi 1.7 Pb 0.3 Sr 2-x Pr x Ca 2 Cu 3 O y (0,10≤x≤0,50, refer to PrF 3 ) are measured experimentally. The valence m(x), the charge q(x) and the 4f(x)-, 5d(x)-levels population of Pr are determined from experimental shifts. It is found that the Pr valence is near 3; the small valence increasing m≅3,04 at x=0,1 is observed. The small of Pr 5d-electron localization in ceramics in comparison with PrF 3 is revealed (∼0,1-0,2 5d-electron per Pr-atom). The probable cause of the superconductivity suppression in Y 1-x Pr xB a 2 Cu 3 O 7-δ system is discussed. 26 refs.; 6 figs.; 1 tab

  10. Temperature behavior of the hole density of (Bi,Pb)-2212 single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Ghafari, Aliakbar; Janowitz, Christoph; Dwelk, Helmut; Krapf, Alica; Manzke, Recardo [Institute of Physics, Humboldt University of Berlin, Newtonstr. 15, D-12489 Berlin (Germany); Ariffin, Ahmad Kamal [Dept. of Physics, Universiti Pendidikan Sultan Idris, 35900 Tanjong Malim (Malaysia)

    2012-07-01

    One of the most puzzling anomalies of high-T{sub c} cuprates is the strong temperature dependence of the Hall coefficient (R{sub H}) and the hole density (n{sub H}). Gor'kov and Teitel'baum (GT) showed by using experimental data of La{sub 2-x}Sr{sub x}CuO{sub 4} (LSCO) that the number of holes per Cu atom, n{sub H}, changes with temperature according to n{sub H}(T,x)=n{sub 0}(x)+n{sub 1}(x)exp(-{Delta}(x)/T). To clarify the temperature dependence of n{sub H} we have determined n{sub H} by X-ray absorption spectra (XAS) at the CuL{sub 3} edge for nearly optimum and slightly underdoped (Bi,Pb)-2212 single crystals. Our results point out that the GT formula cannot fit our data and therefore must be extended to the three terms.

  11. Determination of ionic conductivity in the Bi-Si-O and Pb-Si-O glasses

    Directory of Open Access Journals (Sweden)

    Karczewski J.

    2018-03-01

    Full Text Available Impedance spectroscopy measurements in various gas atmospheres were carried out in order to explain the doubts about the type of carriers and the mechanism of electrical conductivity in Bi-Si-O and Pb-Si-O glasses. In bismuth silicate glass, a typical ionic conductivity with oxygen ions as charge carriers was observed. The level of electrical conductivity of the glass at 400 °C was 5 × 10-8 S·cm-1, with the activation energy of 1.3 eV and was independent of measuring atmosphere. In the case of lead silicate glasses, the conductivity changed with measuring atmosphere. Two types of charge carriers: oxygen ions and proton ions were postulated. Proton conductivity measured in wet argon at temperature 400 °C was estimated at the level of 4 × 10-8 S·cm-1 while the oxygen ions conductivity in such conditions was 78 × 10-8 S·cm-1. We suggest that both types of charge carriers are transported along the same conduction paths using oxygen defects in the glass structure.

  12. Inherent Safety Features and Passive Prevention Approaches for Pb/Bi-cooled Accelerator-Driven Systems

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Johan

    2003-03-01

    This thesis is devoted to the investigation of passive safety and inherent features of subcritical nuclear transmutation systems - accelerator-driven systems. The general objective of this research has been to improve the safety performance and avoid elevated coolant temperatures in worst-case scenarios like unprotected loss-of-flow accidents, loss-of-heat-sink accidents, and a combination of both these accident initiators. The specific topics covered are emergency decay heat removal by reactor vessel auxiliary cooling systems, beam shut-off by a melt-rupture disc, safety aspects from locating heat-exchangers in the riser of a pool-type reactor system, and reduction of pressure resistance in the primary circuit by employing bypass routes. The initial part of the research was focused on reactor vessel auxiliary cooling systems. It was shown that an 80 MW{sub th} Pb/Bi-cooled accelerator-driven system of 8 m height and 6 m diameter vessel can be well cooled in the case of loss-of-flow accidents in which the accelerator proton beam is not switched off. After a loss-of-heat-sink accident the proton beam has to be interrupted within 40 minutes in order to avoid fast creep of the vessel. If a melt-rupture disc is included in the wall of the beam pipe, which breaks at 150 K above the normal core outlet temperature, the grace period until the beam has to be shut off is increased to 6 hours. For the same vessel geometry, but an operating power of 250 MW{sub th} the structural materials can still avoid fast creep in case the proton beam is shut off immediately. If beam shut-off is delayed, additional cooling methods are needed to increase the heat removal. Investigations were made on the filling of the gap between the guard and the reactor vessel with liquid metal coolant and using water spray cooling on the guard vessel surface. The second part of the thesis presents examinations regarding an accelerator-driven system also cooled with Pb/Bi but with heat-exchangers located

  13. Inherent Safety Features and Passive Prevention Approaches for Pb/Bi-cooled Accelerator-Driven Systems

    International Nuclear Information System (INIS)

    Carlsson, Johan

    2003-03-01

    This thesis is devoted to the investigation of passive safety and inherent features of subcritical nuclear transmutation systems - accelerator-driven systems. The general objective of this research has been to improve the safety performance and avoid elevated coolant temperatures in worst-case scenarios like unprotected loss-of-flow accidents, loss-of-heat-sink accidents, and a combination of both these accident initiators. The specific topics covered are emergency decay heat removal by reactor vessel auxiliary cooling systems, beam shut-off by a melt-rupture disc, safety aspects from locating heat-exchangers in the riser of a pool-type reactor system, and reduction of pressure resistance in the primary circuit by employing bypass routes. The initial part of the research was focused on reactor vessel auxiliary cooling systems. It was shown that an 80 MW th Pb/Bi-cooled accelerator-driven system of 8 m height and 6 m diameter vessel can be well cooled in the case of loss-of-flow accidents in which the accelerator proton beam is not switched off. After a loss-of-heat-sink accident the proton beam has to be interrupted within 40 minutes in order to avoid fast creep of the vessel. If a melt-rupture disc is included in the wall of the beam pipe, which breaks at 150 K above the normal core outlet temperature, the grace period until the beam has to be shut off is increased to 6 hours. For the same vessel geometry, but an operating power of 250 MW th the structural materials can still avoid fast creep in case the proton beam is shut off immediately. If beam shut-off is delayed, additional cooling methods are needed to increase the heat removal. Investigations were made on the filling of the gap between the guard and the reactor vessel with liquid metal coolant and using water spray cooling on the guard vessel surface. The second part of the thesis presents examinations regarding an accelerator-driven system also cooled with Pb/Bi but with heat-exchangers located in the

  14. Mean residence times of atmospheric aerosols in the boundary layer as determined from 210Bi/210Pb activity ratios

    International Nuclear Information System (INIS)

    Papastefanou, C.; Bondietti, E.A.

    1991-01-01

    Concentrations of radioactive 210 Pb and 210 Bi were measured in surface air after chemical separation and radiochemical analysis in an annual cycle and were used to determine aerosol residence times in the lower atmosphere. It was concluded that residence times of 8 days would apply to aerosols of 0.3 μm activity median aerodynamic diameter (AMAD). Cascade impactor data are also presented in relating the residence times and the AMAD of atmospheric aerosols. (author)

  15. High-density Bi-Pb-Sr-Ca-Cu-O superconductor prepared by rapid thermal melt processing

    Science.gov (United States)

    Moon, B. M.; Lalevic, B.; Kear, B. H.; McCandlish, L. E.; Safari, A.; Meskoob, M.

    1989-10-01

    A high quality, dense Bi-Pb-Sr-Ca-Cu-O superconductor has been successfully synthesized by rapid thermal melt processing. Conventionally sintered pellets were melted at 1200 °C, cooled rapidly, and then annealed. As-melted samples exhibited semiconductor behavior, which upon annealing became superconducting at 115 K [Tc(zero)=105 K]. A detailed study of various processing techniques has been carried out.

  16. Martensitic transformation behavior in Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jai-young; Chun, Su-jin; Kim, Nam-suk; Cho, Jeung-won; Kim, Jae-hyun [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Yeom, Jong-taek [Light Metal Division, Korea Institute of Materials Science (KIMS), Changwon 642-831 (Korea, Republic of); Kim, Jae-il [Materials Science and Engineering, University of Dong-A, Hadan-dong, Saha-gu, Busan 604-714 (Korea, Republic of); Nam, Tae-hyun, E-mail: tahynam@gnu.ac.kr [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of)

    2013-12-15

    Graphical abstract: - Highlights: • Ag, In and Sn were soluble in TiNi matrix, while Sb, Te, Tl, Pb and Bi were not. • The B2-R-B19′transformation occurred in Ti-Ni-(Ag, In, Sn) alloys. • Solid solution hardening was essential for inducing the B2-R transformation. - Abstract: The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (

  17. Martensitic transformation behavior in Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

    International Nuclear Information System (INIS)

    Jang, Jai-young; Chun, Su-jin; Kim, Nam-suk; Cho, Jeung-won; Kim, Jae-hyun; Yeom, Jong-taek; Kim, Jae-il; Nam, Tae-hyun

    2013-01-01

    Graphical abstract: - Highlights: • Ag, In and Sn were soluble in TiNi matrix, while Sb, Te, Tl, Pb and Bi were not. • The B2-R-B19′transformation occurred in Ti-Ni-(Ag, In, Sn) alloys. • Solid solution hardening was essential for inducing the B2-R transformation. - Abstract: The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (< Hv 200) of the alloys displaying the B2-B19′ transformation. Solid solution hardening was an important factor for inducing the B2-R transformation in Ti–Ni–X (X = non-transition elements) alloys

  18. Gamma ray shielding characteristic of BiZnBo-SLS and PbZnBo-SLS glass

    Science.gov (United States)

    Syuhada Ahmad, Nor; Shahrim Mustafa, Iskandar; Mansor, Ishak; Malik, Muhammad Fadhirul Izwan bin Abdul; Ain Nabilah Razali, Nur; Nordin, Sufiniza

    2018-05-01

    The radiation shielding and optical properties of x [RmOn] (0.5‑x) [ZnO] 0.2 [B2O3] 0.3 [SLS], where RmOn are Bi2O3 and PbO with x = 0.05, 0.10, 0.20, 0.30, 0.40, and 0.45 have been prepared by using the melt-quenching method at 1200 °C and was investigated on their physical, structural and gamma ray shielding properties. Field-emission scanning electron microscope (FESEM) data revealed that the particle morphologies is aggregated and irregular in shapes and size. Energy dispersive x-ray spectroscopy (EDS) elemental mapping data confirmed that all mentioned element all present on the prepared glass. Soda Lime Silica (SLS) that is mainly composed of SiO2 has been utilized in this study as the source of SiO2 for fabrication of glass system. From the result, the density and molar volume of both glass samples increased as Bi2O3 and PbO content increased. The gamma ray shielding properties, such as linear attenuation and mass attenuation coefficient, were increased while half value layer (HVL) and mean free path (MFP) were decreased as the increased in Bi2O3 and PbO concentrations. It is recognized that the mass attenuation coefficient value of Bi2O3 and PbO glass are slightly different. From this study, it can be concluded that from the non-toxicity and shielding point of view, the bismuth glass is a good shield to gamma radiation as compared to lead glass.

  19. Search for 1/sup +/ states in /sup 208/Pb by /sup 208/Pb(p, p') and the /sup 209/Bi(d, /sup 3/He) reactions

    Energy Technology Data Exchange (ETDEWEB)

    Ikegami, H.; Yamazaki, T.; Morinobu, S.; Katayama, I.; Fujiwara, M. [Osaka Univ., Suita (Japan). Research Center for Nuclear Physics; Ikegami, Hidetsugu; Muraoka, Mitsuo [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

    1980-01-01

    Proton inelastic scattering experiment on Pb-208 was carried out by using 65 MeV protons from a 230 cm AVF cyclotron, to study the 1/sup +/ states in Pb-208. The momentum of outgoing protons was analyzed by the magnetic spectrograph RAIDEN. The 7.06 MeV state was very weakly excited. In order to identify 1/sup +/ states from the angular distributions of the inelastic scattering, the proton spectra scattered from the well known 1/sup +/ state in Pb-206 were measured. because of masking by a strong neighbouring peak, the differential cross section of the 1/sup +/ state was measured only at two points. The comparison between the experiment and distorted wave calculation for the 1/sup +/ state (1.703 MeV) in Pb-206 was made, and the results implied that the 1/sup +/ states in Pb-208 would also be weakly excited even if these states are good particle-hole states, Next, Bi-209 (d, He-3) reaction experiment was performed. The comparison between the preliminary results and the calculated results based on the shell model is shown in a figure. The overall agreement between the experimental and theoretical results seems to be good. However, the existence of the 1/sup +/ state has not been confirmed, and will be confirmed in the next step to be done.

  20. Effect of composition on the fabrication and properties of Ag-Cu alloy sheathed (Bi,Pb)2223 tapes

    International Nuclear Information System (INIS)

    Nakamura, Yuichi; Nakashima, Sohei; Inada, Ryoji; Oota, Akio

    2004-01-01

    To achieve high J c values as well as high mechanical strength, the effects of Ag-Cu alloy sheath and initial composition of precursor on the microstructure and J c properties of Ag-Cu alloy sheathed tapes were investigated. The alkaline-earth cuprate particles were found to form preferentially near the interface between superconducting core and sheath. Although the worse (Bi,Pb)2223 purity and microstructure of alloy sheathed tapes, the reduction of J c values of the tapes was small especially in 7-filaments tapes. This might be explained by the well grain alignment of (Bi,Pb)2223 into the middle region of the filament due to the high strength of alloy sheath. The usage of the Cu deficient composition was effective to reduce the total amount of 14:24 particle while the filament thickness should be thin to maintain J c values for Ag-Cu alloy sheathed tapes due to the lack of Cu diffusion from the sheath to convert 2212 into (Bi,Pb) in the middle region of the filament

  1. Synthesis and evaluation of tetraphosphonates labelled with {sup 212}Bi, {sup 212}Pb and {sup 165}Er

    Energy Technology Data Exchange (ETDEWEB)

    Hassfjell, S.P

    1997-08-01

    The main goal of this work has been to achieve a synthesis of radiolabelled phosphonates for the improvement of diagnostic and therapy of osteoblastic osteosarcoma and sclerotic bone metastases. {sup 212}Bi-DOTMP is shown to be an in vivo stable bone seeking radiopharmaceutical with a potential for a {alpha}-particle therapy of the above mentioned diseases. It has biodistribution characteristics similar to {sup 153}Sm-EDTMP, which is now formally approved in several countries, most recently in the US. {sup 212}Pb-DOTMP is also a promising candidate having the advantage of increasing the effective half life of the {alpha}-emitter, although loss of some of the in vivo generated {sup 212}Bi may be a problem. A generator has been developed for the production of the {alpha}-emitting radionuclide {sup 212}Bi and its parent nuclide {sup 212}Pb. The generator is based on the emanation of {sup 220}Rn from ({sup 228}Th)barium stearate. The decay product of {sup 220}Rn, {sup 212}Pb deposits on the walls of a polyethylene bottle, and can be wasted off with distilled water. The generator shows no leakage of any long-lived parent nuclides, is easy to operate and has a high degree of radiation safety.

  2. Investigation on gamma and neutron radiation shielding parameters for BaO/SrO‒Bi2O3‒B2O3 glasses

    Science.gov (United States)

    Sayyed, M. I.; Lakshminarayana, G.; Dong, M. G.; Ersundu, M. Çelikbilek; Ersundu, A. E.; Kityk, I. V.

    2018-04-01

    In this work, mass attenuation coefficients (μ/ρ), effective atomic number (Zeff), electron density (Ne), mean free path (MFP), and half-value layer (HVL) of 20 BaO/SrO‒(x) Bi2O3‒(80‒x) B2O3 glasses (where x=10, 20, 30, 40, 50 and 60 mol%) were calculated using WinXCom program and MCNP5 code. The obtained (μ/ρ) results using both MCNP5 code and WinXCom program were in good agreement. It is found that the addition of Bi2O3 leads to increase the Zeff values in both BaO/SrO‒Bi2O3‒B2O3 glass systems. However, the Zeff values of the BaO‒Bi2O3‒B2O3 glass system are higher than those of the SrO‒Bi2O3‒B2O3 glasses. The fast neutrons effective removal cross sections (ΣR) for 20 SrO‒40 Bi2O3‒40 B2O3 glass is the highest among all studied glasses. The calculated half-value layer values were compared with different glass systems and it was found that the shielding properties of the selected glasses are comparable or even better than other glass systems such as phosphate glasses.

  3. Gamma-ray attenuation studies of PbO-BaO-B2O3 glass system

    International Nuclear Information System (INIS)

    Singh, Narveer; Singh, Kanwar Jit; Singh, Kulwant; Singh, Harvinder

    2006-01-01

    PbO-BaO-B 2 O 3 glass system has been investigated in terms of molar mass, mass attenuation coefficient and half value layer parameters by using gamma-ray at 511,662 and 1274keV photon energies. Gamma-ray attenuation coefficients of the prepared glass samples have been compared with tabulations based upon the results of XCOM. Good agreement has been observed between experimental and theoretical tabulations. Our results have uncertainty less than 3%. Radiation shielding properties of the glass system have been compared with some standard radiation shielding concretes

  4. First Pb-Pb dating results from carbonado diamonds from Chapada Diamantina (BA) and Jequitinhonha River (MG), Espinhaco Range

    International Nuclear Information System (INIS)

    Chaves, Mario Luiz de Sa Carneiro; Sano, Yuji; Chambel, Luis

    2005-01-01

    Most carbonados found in Brazil occur along the Espinhaco Range, associated to conglomeratic rocks of the Espinhaco Supergroup. This paper presents Pb-Pb radiometric ages on mineral inclusions (quartz, rutile and clay) and matrix of carbonados from the Andarai and Jequitinhonha River areas. Even with a large experimental error, the results obtained of 3,8±1,8Ga and 3,3±0,7 Ga respectively, are of regional geologic interest. The minimum carbonado formation age (ca.2,5 Ga) is older than the Espinhaco Supergroup deposition age (≅ 1,7 Ga). Other evidences suggest that this minimum age corresponds to the seed aggregation phase; the crustal inclusions being aggregated in an environment rich in high-energy radioactive particles. (author)

  5. Ba2+ Doped CH3NH3PbI3 to Tune the Energy State and Improve the Performance of Perovskite Solar Cells

    International Nuclear Information System (INIS)

    Zhang, Hanbing; Shang, Ming-hui; Zheng, Xiaoying; Zeng, Zhaobing; Chen, Renjie; Zhang, Ying; Zhang, Jing; Zhu, Yuejin

    2017-01-01

    Highlights: •Ba doping enlarges the energy band gap of MAPb 1-x Ba x I 3 . •Voc and Jsc are enhanced in perovskite solar cells. •DFT calculation proves the experiment results. -- Abstract: Elements substitution and doping in perovskite CH 3 NH 3 PbI 3 exhibit versatile tunability of energy band structure and opto-electric properties. Ba 2+ is chosen to substitute Pb 2+ for its similar valence state and ionic radius with Pb 2+ . Ba 2+ doping in perovskite (mol% <5) slightly enlarges the optic energy gap by conduction band minimum(CBM) upshifting to vacuum energy level, which is due to the smaller electronegativity of Ba than Pb. The enlarged band gap is also verified by density function theory calculations. In n-i-p structure perovskite solar cells (PSCs), because of the higher CBM of doped perovskite, the Fermi energy difference between n and p side is enlarged and the electron injection from the perovskite to TiO 2 is improved. Thus, both the photovoltage and photocurrent are improved by small amount Ba 2+ doping, resulting optimized 17.4% efficiency under AM1.5. This work reveals the relationship between the doping element property and the energy band structure of the perovskite, and highlights the doping method to improve the performance of PSCs.

  6. Combinatorial processing libraries for bulk BiFeO3-PbTiO3 piezoelectric ceramics

    International Nuclear Information System (INIS)

    Hu, W.; Tan, X.; Rajan, K.

    2010-01-01

    A high throughput approach for generating combinatorial libraries with varying processing conditions for bulk ceramics has been developed. This approach utilized the linear temperature gradient in a tube furnace to screen a whole temperature range for optimized preparation. With this approach, the processing of 0.98[0.6BiFeO 3 -0.4PbTiO 3 ]-0.02Pb(Mg 1/3 Nb 2/3 )O 3 ceramic powders and pellets for high-temperature piezoelectric applications was demonstrated to identify the best synthesis conditions for phase purity. The dielectric property measurement on the as-processed solid solution ceramics confirmed the high Curie temperature and the improved loss tangent with the Pb(Mg 1/3 Nb 2/3 )O 3 doping. (orig.)

  7. Anomalous atomic displacement parameters and local dynamics in the Curie range of a Pb-free relaxor ferroelectric system (Bi1-xBax)(Fe1-xTix)O3(0.36 ≤ x ≤ 0.50)

    Science.gov (United States)

    Singh, Anar; Moriyoshi, Chikako; Kuroiwa, Yoshihiro; Pandey, Dhananjai

    2018-04-01

    We report here the relaxor ferroelectric (RFE) behaviour in a multiferroic solid solution system, (Bi1-xBax)(Fe1-xTix)O3, at a critical disorder level of xC ˜ 0.35 in BiFeO3 and 0.65 (i.e., 1-xC = 0.35) in BaTiO3 similar to the 1:2 ratio of Mg2+ and Nb5+ in the canonical RFE Pb(Mg1/3Nb2/3)O3. This Pb-free system, like canonical Pb-based RFEs, does not exhibit macroscopic symmetry breaking and shows only the signatures of ergodicity breaking at Vogel-Fulcher freezing temperature (TVF). The atomic displacement parameters (ADPs) of Fe3+/Ti4+ and O2-, obtained using high wave vector (Q) and high-resolution synchrotron x-ray diffraction data as a function of temperature, show anomalous diffuse peaks in the Curie range. It is shown that the diffuse peak in ADPs is due to softening of the vibrational frequencies of the B-O chain (B = Fe3+/Ti4+ and O = O2-) below the Burns temperature (TB) followed by hardening below the characteristic temperature (T'm), which corresponds to a peak in the dielectric permittivity (ɛ').

  8. Magnetic and dielectric properties of alkaline earth Ca2+ and Ba2+ ions co-doped BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Yang, C.; Liu, C.Z.; Wang, C.M.; Zhang, W.G.; Jiang, J.S.

    2012-01-01

    Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles, Bi 0.8 Ca 0.2−x Ba x FeO 3 (x=0–0.20), were prepared by a sol–gel method. The phase structure, grain size, dielectric and magnetic properties of the prepared samples were investigated. The results showed that the lattice structure of the nanoparticles transformed from rhombohedral (x=0) to orthorhombic (x=0.07–0.19) and then to tetragonal (x=0.20) with x increased. The dielectric properties of the nanoparticles were affected by the properties of the substitutional ions as well as the crystalline structure of the samples. The magnetic properties of the nanoparticles were greatly improved and the T N of the nanoparticles was obviously increased. All the Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles presented the high ratio of M r /M from 0.527 to 0.571 and large coercivity from 4.335 to 5.163 KOe. - Highlights: ► Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles were prepared using a sol–gel method. ► The magnetic properties of the nanoparticles are greatly improved. ► The Neel temperature (T N ) of the nanoparticles is greatly increased. ► Doped ions and crystal structure affect the dielectric properties of the nanoparticles.

  9. Dielectric and Energy Storage Properties of Ba0.65Sr0.35TiO3 Ceramics Modified by BiNbO4

    Science.gov (United States)

    Zheng, Yi; Zhang, Jihua; Wei, Meng; Dong, Xiangxiang; Huang, Jiapeng; Wu, Kaituo; Chen, Hongwei

    2018-02-01

    (1 - x) (Ba0.65Sr0.35TiO3)-xBiNbO4 (x = 0.0-0.15) ceramic were prepared by solid-state reaction method. The phase composition, microstructure, dielectric properties, polarization-electric field, breakdown strength and energy storage behaviors for the BiNbO4-modified Ba0.65Sr0.35TiO3 ceramics were investigated. With the addition of BiNbO4, the remnant polarization and saturation polarization decreased and the nonlinearity was suppressed. When x = 0.07, the maximum recoverable energy storage achieved was 0.5 J/cm3, 1.5 times that of un-doped Ba0.65Sr0.35TiO3 ceramics, with an efficiency of 96.89% and a breakdown electric field reaching 15.3 kV/mm. Therefore, BiNbO4 doping could improve the energy storage properties of Ba0.65Sr0.35TiO3 for high-energy pulse capacitor application.

  10. Evidence for collective {delta}T{sub c} pinning in superconducting (K, Ba)BiO{sub 3} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Harneit, W [Centre National de la Recherche Scientifique (CNRS), 38 -Grenoble (France). Lab. d` Etudes des Proprietes Electroniques des Solides; Klein, T [Centre National de la Recherche Scientifique (CNRS), 38 - Grenoble (France). Lab. d` Etudes des Proprietes Electroniques des Solides; Baril, L [Centre National de la Recherche Scientifique (CNRS), 38 - Grenoble (France). Lab. d` Etudes des Proprietes Electroniques des Solides; Escribe-Filippini, C [Centre National de la Recherche Scientifique (CNRS), 38 - Grenoble (France). Lab. d` Etudes des Proprietes Electroniques des Solides

    1996-10-10

    The nature of pinning has been investigated in the three-dimensional high-T{sub c} superconductor (K, Ba)BiO{sub 3}. We show that the magnetic-field dependence of the critical current deduced from pulsed-field magnetization measurements can be well described by the collective-pinning theory on a large temperature range 0.06

  11. Lattice dynamics of Ba1-xKxBiO3 as studied by neutron scattering and computer simulation

    International Nuclear Information System (INIS)

    Belushkin, A.V.; Vagov, A.V.; Zemlyanov, M.G.; Parshin, P.P.

    1991-01-01

    A time-of-flight neutron inelastic scattering study of the lattice dynamics of Ba 1-x K x BiO 3 for x=0.0 and x=0.4 has been performed for the temperatures 10 K, 80 K and 290 K. No temperature effects were found for the generalized phonon density of states. The phonon spectrum of a superconducting sample reveals less in number van Hove singularities and softens in comparison with that of the nonsuperconducting one. On the basis of the simple model for interatomic potential the lattice dynamics of this system was calculated. Some features of the structural phase diagram and the optical spectroscopy data were explained using this model. The calculated phonon density of states was found to be in good agreement with experiment. 36 refs.; 3 figs

  12. Multiferroic properties of BiFeO{sub 3}/BaTiO{sub 3} multilayered thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Savita [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Department of Applied Physics, Delhi Technological University, Delhi 110042 (India); Tomar, Monika [Physics Department, Miranda House, University of Delhi, Delhi 110007 (India); Kumar, Ashok [CSIR—National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Puri, Nitin K. [Department of Applied Physics, Delhi Technological University, Delhi 110042 (India); Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2014-09-01

    Multilayered structures of multiferroic BiFeO{sub 3} (BFO) and ferroelectric BaTiO{sub 3} (BTO) have been fabricated using pulsed laser deposition (PLD). Ferromagnetic and ferroelectric properties of the multilayered system (BFO/BTO) have been investigated. It could be inferred that the magnetization increases with the incorporation of BTO buffer layer, which indicates a coupling between the ferroelectric and ferromagnetic orders. Vibrating sample magnetometer (VSM) measurements performed on the prepared multiferroic samples show that the magnetization is significantly increased (M{sub s}=56.88 emu/cm{sup 3}) for the multilayer system with more number of layers (four) keeping the total thickness of the multilayered system constant (350 nm) meanwhile maintaining the sufficiently enhanced ferroelectric properties (P{sub r}=29.68 µC/cm{sup 2})

  13. Evidence for phonon-mediated coupling in superconducting Ba0.6K0.4BiO3

    International Nuclear Information System (INIS)

    Hinks, D.G.; Dabrowski, B.; Richards, D.R.; Jorgensen, J.D.; Pei, S.; Zasadzinski, J.F.

    1989-01-01

    Superconducting Ba 0.6 K 0.4 BiO 3 , with a T c of 30 K, shows a large 18 O isotope effect which indicates that phonons are involved in the pairing mechanism. Infrared reflectivity measurements indicate a value for the superconducting gap consistent with moderate coupling (2Δ/k T c = 3.5 ± 0.5). A mediating energy for pairing of about 40 meV would be required to obtain a T c of 30 K. Strong coupling of electrons by optical phonons (which are present in this material with energies up to 80 meV) could account for the observed transition temperature. Recent tunneling spectroscopy shows the presence of strongly coupled optical phonons in the 40 to 70 meV region, indicating that superconductivity in this material may be phonon mediated

  14. Pressure-induced phase transition and octahedral tilt system change of Ba2BiSbO6

    International Nuclear Information System (INIS)

    Lufaso, Michael W.; Macquart, Rene B.; Lee, Yongjae; Vogt, Thomas; Loye, Hans-Conrad zur

    2006-01-01

    High-resolution X-ray synchrotron powder diffraction studies under high-pressure conditions are reported for the ordered double perovskite Ba 2 BiSbO 6 . Near 4GPa, the oxide undergoes a pressure-induced phase transition. The symmetry of the material changes during the phase transition from space group R3-bar to space group I2/m, which is consistent with a change in the octahedral tilting distortion from an a - a - a - type to a 0 b - b - type using the Glazer notation. A fit of the volume-pressure data using the Birch-Murnagaham equation of state yielded a bulk modulus of 144(8)GPa for the rhombohedral phase

  15. Anomalous field dependence of the Sommerfeld coefficient in the isotropic (K,Ba)BiO{sub 3} superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Klein, T.; Marcenat, C.; Bouquet, F.; Junod, A.; Blanchard, S.; Marcus, J

    2004-08-01

    We report on specific heat measurements in high quality (K,Ba)BiO{sub 3} single crystals (T{sub c}{approx}31.5 K). A well defined specific heat jump is clearly visible at T{sub C{sub p(H)}} in the entire investigated field range (up to 13 T). However, the corresponding T{sub C{sub p(H)}} exhibits an anomalous positive curvature and the amplitude of the jump rapidly decreases with field suggesting a non-linear increase of the Sommerfeld coefficient ({gamma}(H)). This anomalous behaviour is confirmed by low temperature measurements which show that {gamma}(H){proportional_to}H{sup {alpha}} with {alpha}{approx}0.65.

  16. Direct submillimeter absorptivity measurements on epitaxial Ba1-xKxBiO3films at 2K

    International Nuclear Information System (INIS)

    Miller, D.; Richards, P.L.; Nicol, E.J.; Hellman, E.S.; Hartford, E.H. Jr.; Platt, C.E.; Schweinfurth, R.A.; VanHarlingen, D.J.; Amano, J.

    1993-04-01

    We have used a bolometric technique to obtain accurate low temperature loss data for epitaxial thin films of Ba 0.6 K 0.4 BiO 3 from 30 to 700 cm -1 . These films were grown on MgO and SrTiO 3 substrates by MBE, off-axis sputtering and laser deposition techniques. All films show a strong absorption onset near the BCS tunneling gap of 3.5k B T c . We have analyzed these data using a Kramers-Kronig transformation and have corrected for finite film thickness effects. Results indicate that the absorption onset is consistent with a superconducting energy gap. Comparison is made with predictions based on strong coupling Eliashberg theory using α 2 F(ω) spectra obtained from the literature. While we are able to fit the overall measured absorptivity, we are unable to fit the structure observed in our data

  17. Thermal hydraulic analysis of Pb-Bi cooled HYPER fuel assemblies using SLTHEN code

    International Nuclear Information System (INIS)

    Tak, Nam Il; Song, Tae Y.; Park, Won S.; Kim, Chang Hyun

    2002-12-01

    In the present work, the existing SLTHEN code, which had been originally developed for subchannel analysis of sodium cooled fast reactors, was modified and applied to the Pb-Bi cooled HYPER core which consists of 237 fuel assemblies (TRU assemblies). In the analysis of single fuel assembly having chopped cosine power profile, the validation and the assessment of usefulness of the modified SLTHEN were focused. In the quantitative comparison, the results of the modified SLTHEN agreed well with those of analytical calculations and of MATRA. For the qualitative approaches, the sensitivity calculations for intra-assembly gap flow and turbulent mixing parameter were used. The sensitivity analysis results showed that the modified SLTHEN can provide reasonable simulations of subchannel thermal hydraulics. In particular, turbulent mixing parameter which is known as the most uncertain parameter in subchannel analyses did not affect largely the maximum cladding temperature. Therefore, it can be said that the results of single assembly show the usefulness of the modified SLTHEN code for thermal hydraulic analysis and design of HYPER under the conceptual design stage. In order to assess intra-assembly heat transfer, subchannel analyses were implemented for two types of 7 assemblies; 1) artificial 7 fuel assemblies to maximize intra-assembly heat transfer, 2) central 7 fuel assemblies in the HYPER reference core. The results showed that the modified SLTHEN can reasonably simulate intra-heat transfer and the amount of intra-assembly heat transfer is not so large in HYPER conditions. Particularly, intra-heat transfer did not affect the maximum coolant and the maximum cladding temperatures which are major parameters in conceptual core designs. The capability of full core thermal hydraulic analysis was confirmed by the analysis of 45 fuel assemblies in 1/6 HYPER core at the first cycle. The SLTHEN predicted that the reference design parameters are acceptable in terms of thermal

  18. Experimental Cross Sections for Reactions of Heavy Ions and 208Pb, 209Bi, 238U, and 248Cm Targets

    International Nuclear Information System (INIS)

    Patin, Joshua B.

    2002-01-01

    The study of the reactions between heavy ions and 208 Pb, 209 Bi, 238 U, and 248 Cm targets was performed to look at the differences between the cross sections of hot and cold fusion reactions. Experimental cross sections were compared with predictions from statistical computer codes to evaluate the effectiveness of the computer code in predicting production cross sections. Hot fusion reactions were studied with the MG system, catcher foil techniques and the Berkeley Gas-filled Separator (BGS). 3n- and 4n-exit channel production cross sections were obtained for the 238 U( 18 O,xn) 256-x Fm, 238 U( 22 Ne,xn) 260-x No, and 248 Cm( 15 N,xn) 263-x Lr reactions and are similar to previous experimental results. The experimental cross sections were accurately modeled by the predictions of the HIVAP code using the Reisdorf and Schaedel parameters and are consistent with the existing systematics of 4n exit channel reaction products. Cold fusion reactions were examined using the BGS. The 208 Pb( 48 Ca,xn) 256-x No, 208 Pb( 50 Ti,xn) 258-x Rf, 208 Pb( 51 V,xn) 259-x Db, 209 Bi( 50 Ti,xn) 259-x Db, and 209 Bi( 51 V,xn) 260-x Sg reactions were studied. The experimental production cross sections are in agreement with the results observed in previous experiments. It was necessary to slightly alter the Reisdorf and Schaedel parameters for use in the HIVAP code in order to more accurately model the experimental data. The cold fusion experimental results are in agreement with current 1n- and 2n-exit channel systematics

  19. Facile synthesis, structure elucidation, and magnetic properties of perovskite BaTb{sub 1-x}Bi{sub x}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Farid, Muhammad Asim; Zhang, Hao; Li, Guobao; Liao, Fuhui; Lin, Jianhua [Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing (China); Yang, Aimei [College of Materials Science and Engineering, Guilin University of Technology, 541004, Guilin (China); Tian, Gengfang; Wu, Meimei [Neutron Scattering Laboratory, Department of Nuclear Physics, China Institute of Atomic Energy, 102413, Beijing (China)

    2017-03-17

    A series of perovskite BaTb{sub 1-x}Bi{sub x}O{sub 3} (0.0 ≤ x ≤ 0.25) solid solutions were synthesized by a typical solid-state method. Their structures were analyzed by a combination of X-ray diffraction, neutron diffraction, and selected-area electron diffraction. All of the materials crystalize in the P1 space group [a = 6.0582(1) Aa, b = 6.0473(1) Aa, c = 6.0693(1) Aa, α = 60.00(1) , β = 59.84(1) , γ = 60.06(1) for x = 0.0 at room temperature]. Magnetic measurements revealed that the magnetic-ordering temperature decreases with increasing Bi content in BaTb{sub 1-x}Bi{sub x}O{sub 3}; therefore, the presence of Bi decreases the magnetic interactions of Tb. Furthermore, the magnetic structure for BaTb{sub 1-x}Bi{sub x}O{sub 3} has been fully described in space group P1. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. An improved method for the separation of 210Bi and 210Po from 210Pb by using solid-phase extraction disk membranes: environmental applications

    International Nuclear Information System (INIS)

    Marley, N.A.; Gaffney, J.S.; Orlandini, K.A.; Cunningham, M.M.; Drayton, P.J.

    1999-01-01

    An improved method is described for the rapid separation of 210 Bi and 210 Po from the parent radionuclide, 210 Pb, in environmental samples. After the metals were leached from a variety of matrices, they were converted to their anionic chloride complexes by addition of 1 M HCl. These complexes can be separated by solid-phase extraction with disk extraction membranes impregnated with anionic chelating particles. This separation technique takes advantage of the differences in sorption behavior of the chloride complexes to strongly basic anion exchange groups. The extraction membranes can then be counted directly for 210 Bi and 210 Po. If sufficient time is allowed for ingrowth of the daughter, the concentration of the parent 210 Pb in the original sample can be determined from the concentration of 210 Bi. In addition, the ratios of 210 Bi/ 210 Pb and 210 Po/ 210 Pb can be obtained by immediate extraction of 210 Bi followed by ingrowth of 210 Bi for a second determination to establish 210 Pb concentration levels. This can be accomplished easily in order to estimate the residence times of atmospheric aerosols or aqueous colloidal materials. This new technique avoids the time consuming extraction, precipitation, and electroplating procedures used previously and eliminates the experimental errors associated with multiple sample manipulations. (orig.)

  1. Synthesis and photoelectrical performance of nanoscale PbS and Bi2S3 co-sensitized on Ti02 nanotube arrays

    Institute of Scientific and Technical Information of China (English)

    Fanggong Cai; Min Pan; Yong Feng; Guo Yan; Yong Zhang; Yong Zhao

    2017-01-01

    TiO2 films have been widely applied in photovoltaic conversion techniques.TiO2 nanotube arrays (TiO2 NAs) can be grown directly on the surface of metal Ti by the anodic oxidation method.Bi2S3 and PbS nanoparticles (NPs) were firstly co-sensitized on TiO2 NAs (denoted as PbS/Bi2S3(n)/TiO2 NAs) by a two-step process containing hydrothermal and sonication-assisted SILAR method.When the concentration of Bi3+ is 5 mmol/L,the best photoelectrical performance was obtained under simulated solar irradiation.The short-circuit photocurrent (Jsc) and photoconversion efficiency (η) of PbS/Bi2S3(5)/TiO2 NAs electrode were 4.70 mA/cm and 1.13 %,respectively.

  2. Structural, dielectric and magnetic properties of Mn modified xBiFeO{sub 3}-(1−x)BaTiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Zhonghua, E-mail: zhdai@mail.xjtu.edu.cn [College of Mechanics and Materials, Hohai University, Nanjing 210098 (China); Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan); Liu, Lu; Ying, Guobing; Yuan, Ming [College of Mechanics and Materials, Hohai University, Nanjing 210098 (China); Ren, Xiaobing [Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan)

    2017-07-15

    Manganese doped xBiFeO{sub 3}-(1−x)BaTiO{sub 3}(x=0.67–0.82) ceramics were prepared by solid-state method. The structural, dielectric and magnetic properties were investigated after annealing in vacuum at 773 K. X-ray diffraction analysis indicated that all samples crystallized in pure perovskite structure. The ceramics displays a typical ferroelectric loop, with a max remnant polarization P{sub r} of 25.6 µC/cm{sup 2}. The piezoelectric coefficient d{sub 33} of Manganese doped 0.67BiFeO{sub 3}0.33BaTiO{sub 3} is 139 pC/N and its temperature dependence of dielectric constant exhibits a broad anomaly. The Manganese doped 0.75BiFeO{sub 3}0.25BaTiO{sub 3} ceramic shows ferrimagnetism at room temperature, with remnant magnetization M{sub r} of 0.31 emu/g and ferrimagnetic transition temperature T{sub N} of ~420 °C. - Highlights: • In this manuscript, a technique combined Mn doping which is able to fabricate point defects and annealing in vacuum which can stabilize the unstable ion was investigated. We studied the electrical properties of Mn doped BiFeO{sub 3}-BaTiO{sub 3} ceramics after vacuum annealing treatment at appropriate temperature. • Our result is that Mn modification and heat treatment are effective methods to solve the problem of high leakage of BiFeO{sub 3}-BaTiO{sub 3} system ceramic prepared by solid-state method. It exhibited a enhanced field-induced ferromagnetic ordering with promising potential in spintronics and recording media applications.

  3. Cross-sections of (p, xn) nuclear reactions on Pb and Bi by 100 MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Oranj, Leila Mokhtari; Jung, Nam Suk; Oh, Joo Hee; Lee, Arim; Kim, Dong Hyun; Bae, Oryun; Lee, Hee Seock [POSTECH, Pohang (Korea, Republic of)

    2016-04-15

    The development of high-intensity and high-energy accelerator is gaining interest in Korea, in recent years. Rare Isotope Science Project (RISP), Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL), Korea Heavy Ion Medical Accelerator (KHIMA) facilities are being designed. In the frame of above projects, for the safety issue and shielding analysis of the accelerator facility, extensive studies including experimental and simulation on the production yields of residual nuclei induced in the accelerator materials such as Pb, Cu and Bi by protons and heavy ions are in progress. In this work, we measured cross-sections of {sup na}'tPb(p,xn){sup 206,205,204,20{sup ,202}}Bi and {sup 209}Bi(p, xn){sup 207,206,205,204},{sup 203}Po nuclear reactions by the 100-MeV protons. The present experimental data are in good agreement with the results of Titarenkoet al. and Gloris et al.. Experimental data were higher than theoretical data. In other words, results of TALYS code and data in TENDL library underestimated the measured crosss sections and library of TALYS code and TENDL need to be improved.

  4. High frequency permeability and permittivity spectra of BiFeO{sub 3}/(CoTi)-BaM ferrite composites

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Yun; Wu, Xiaohan; Li, Qifan; Yu, Ting; Feng, Zekun, E-mail: fengzekun@hust.edu.cn [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, Zhongyan [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Jiangmen Magsource New Material CO., LTD., 529000 Guangdong (China); Su, Zhijuan; Chen, Yajie; Harris, Vincent G. [Center for Microwave Magnetic Materials and Integrated Circuits, and Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

    2015-05-07

    Low magnetic loss ferrite composites consisting of Ba(CoTi){sub 1.2}Fe{sub 9.6}O{sub 19} and BiFeO{sub 3} (BFO) ferrite were investigated for permeability, permittivity, and high frequency losses at 10 MHz–1 GHz. The phase fraction of BiFeO{sub 3} was quantitatively analyzed by X-ray diffraction measurements. An effective medium approach was employed to predict the effective permeability and permittivity for the ferrite composites, which was found to be in good agreement with experimental data. The experiment demonstrated low magnetic losses (<0.128), modified by BFO phase fraction, while retaining high permeability (∼10.86) at 300 MHz. More importantly, the BFO phase resulted in a reduction of magnetic loss by 32%, as BFO phase increased from 2.7 vol. % to 12.6 vol. %. The effect of BFO phase on magnetic and dielectric properties revealed great potential for use in the miniaturization of high efficiency antennas.

  5. Corrosion behavior of Al-Fe-sputtering-coated steel, high chromium steels, refractory metals and ceramics in high temperature Pb-Bi

    International Nuclear Information System (INIS)

    Abu Khalid, Rivai; Minoru, Takahashi

    2007-01-01

    Corrosion tests of Al-Fe-coated steel, high chromium steels, refractory metals and ceramics were carried out in high temperature Pb-Bi at 700 C degrees. Oxygen concentrations in this experiment were 6.8*10 -7 wt.% for Al-Fe-coated steels and 5*10 -6 wt.% for high chromium steels, refractory metals and ceramics. All specimens were immersed in molten Pb-Bi in a corrosion test pot for 1.000 hours. Coating was done with using the unbalanced magnetron sputtering (UBMS) technique to protect the steel from corrosion. Sputtering targets were Al and SUS-304. Al-Fe alloy was coated on STBA26 samples. The Al-Fe alloy-coated layer could be a good protection layer on the surface of steel. The whole of the Al-Fe-coated layer still remained on the base surface of specimen. No penetration of Pb-Bi into this layer and the matrix of the specimen. For high chromium steels i.e. SUS430 and Recloy10, the oxide layer formed in the early time could not prevent the penetration of Pb-Bi into the base of the steels. Refractory metals of tungsten (W) and molybdenum (Mo) had high corrosion resistance with no penetration of Pb-Bi into their matrix. Penetration of Pb-Bi into the matrix of niobium (Nb) was observed. Ceramic materials were SiC and Ti 3 SiC 2 . The ceramic materials of SiC and Ti 3 SiC 2 had high corrosion resistance with no penetration of Pb-Bi into their matrix. (authors)

  6. Pb solubility of the high-temperature superconducting phase Bi2Sr2Ca2Cu3O10+d

    International Nuclear Information System (INIS)

    Kaesche, S.; Majewski, P.; Aldinger, F.

    1994-01-01

    For the nominal composition of Bi 2.27x Pb x Sr 2 Ca 2 Cu 3 O 10+d the lead content was varied from x=0.05 to 0.45. The compositions were examined between 830 degrees C and 890 degrees C which is supposed to be the temperature range over which the so-called 2223 phase (Bi 2 Sr 2 Ca 2 Cu 3 O 10+d ) is stable. Only compositions between x=0.18 to 0.36 could be synthesized in a single phase state. For x>0.36 a lead containing phase with a stoichiometry of Pb 4 (Sr,Ca) 5 CuO d is formed, for x 2 Sr 2 CaCu 2 O 8+d and cuprates are the equilibrium phases. The temperature range for the 2223 phase was found to be 830 degrees C to 890 degrees C but the 2223 phase has extremely varying cation ratios over this temperature range. Former single phase 2223 samples turn to multi phase samples when annealed at slightly higher or lower temperatures. A decrease in the Pb solubility with increasing temperature was found for the 2223 phase

  7. Enhanced piezoelectricity in plastically deformed nearly amorphous Bi{sub 12}TiO{sub 20}-BaTiO{sub 3} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Dan; Zhao, Minglei, E-mail: zhaoml@sdu.edu.cn; Wang, Chunlei; Wang, Lihai; Su, Wenbin; Gai, Zhigang; Wang, Chunming; Li, Jichao; Zhang, Jialiang [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China)

    2016-07-18

    Bulk Bi{sub 12}TiO{sub 20}-BaTiO{sub 3} (BTO-BT) nanocomposites are fabricated through the high-temperature interfacial reaction between nanometer-sized BaTiO{sub 3} particles and melting Bi{sub 12}TiO{sub 20}. Although the obtained BTO-BT nanocomposites are nearly amorphous and display very weak ferroelectricity, they exhibit relatively strong piezoelectricity without undergoing the electrical poling process. The volume fraction of crystalline Bi{sub 12}TiO{sub 20} is reduced to less than 10%, and the piezoelectric constant d{sub 33} is enhanced to 13 pC/N. Only the presence of the macroscopic polar amorphous phases can explain this unusual thermal stable piezoelectricity. Combining the results from X-ray diffraction, Raman spectroscopy, and thermal annealing, it can be confirmed that the formation of macroscopic polar amorphous phases is closely related to the inhomogeneous plastic deformation of the amorphous Bi{sub 12}TiO{sub 20} during the sintering process. These results highlight the key role of plastically deformed amorphous Bi{sub 12}TiO{sub 20} in the Bi{sub 12}TiO{sub 20}-based polar composites, and the temperature gradient driven coupling between the plastic strain gradient and polarization in amorphous phases is the main poling mechanism for this special type of bulk polar material.

  8. Separation of 210Pb, 210Bi and 210Po by ion exchange and their Iiquid scintillation standardization; Separacion del 210Pb, 210Bi y 2I0Po mediante columna de cambio ionico y su calibracion por centelleo liquido

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, L.; Jimenez, A.; Grau, A.

    1996-07-01

    We applied the CIEMAT/NIST method and alpha/beta discrimination to ''210Pb samples in equilibrium with its daughters, by preparing homogeneous and gel samples. The stability of samples was tested in different available cocktails, HiSafe''TM II, HiSafe''TM III, Ultima-Gold''TM, Ultima-Gold''TM XR, Ultima-Gold''TM AB, Insta-Gel''R and e Insta-Gel''R lI. Also we analyzed the disequilibrium of the radioactive chain 210Pb+210Bi+210Po, achieving an excellent agreement between the results of the spectrum unfolding method and the experimental values. (Author) 13 refs.

  9. Coordination chemistry of the {sup 212}Pb/{sup 212}Bi nuclear transformation: Alpha-emitting radiopharmaceuticals. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Parks, N.J.; Harris, W.R.; Keen, C.L.; Cooper, S.R.

    1992-07-01

    Subdivisions of this project are: (a) the synthesis of prototypical thiolate and dithiocarbamate based hexacoordinate complexes, (b) radiochemical engineering for generation of no-carrier-added lead and bismuth radioelements, (c) the first isolation of bismuth-binding proteins from in vivo studies with cyclotron produced {sup 205/206}Bi tracer, and (d) initial development of transport mechanisms for the intracellular radiobiological study of alpha emitting bismuth, and (e) the initiation of chemical equilibrium studies and biochemical pathways with cyclotron-produced, no-carrier-added, {sup 203}Pb (T{sub 1/2} = 51 hr).

  10. Thermochemical properties of oxides in Y-Ba-Cu-O, Sr-Bi-O, Cu-Nb-O, Sr-Cu-O, Ca-Cu-O, Cu-O and Hg-Ba-Ca-Cu-O systems

    International Nuclear Information System (INIS)

    Moiseev, G.K.; Vatolin, N.A.; Il'inykh, N.I.

    2000-01-01

    Thermochemical properties (ΔH 0 298 , S 0 298 , H 0 298 -H 0 0 , C p (T), C p at T>T melt ) of complex oxides in Y-Ba-Cu-O, Sr-Bi-O, Cu-Nb-O, Sr-Cu-O, Ca-Cu-O, Cu-O and Hg-Ba-Ca-Cu-O systems obtained with application of calculation methods are presented. Nonexperimental methods of estimation, revision and correction of standard formation enthalpies of inorganic compounds are described [ru

  11. Structural, dielectric and ferroelectric properties of (Bi,Na)TiO{sub 3}–BaTiO{sub 3} system studied by high throughput screening

    Energy Technology Data Exchange (ETDEWEB)

    Hayden, Brian E. [Ilika Technologies Plc., Kenneth Dibben House, Enterprise Road, University of Southampton Science Park, Chilworth, Southampton SO16 7NS (United Kingdom); Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Yakovlev, Sergey, E-mail: sergey.yakovlev@ilika.com [Ilika Technologies Plc., Kenneth Dibben House, Enterprise Road, University of Southampton Science Park, Chilworth, Southampton SO16 7NS (United Kingdom)

    2016-03-31

    Thin-film materials libraries of the Bi{sub 2}O{sub 3}–Na{sub 2}O–TiO{sub 2}–BaO system in a broad composition range have been deposited in ultra-high vacuum from elemental evaporation sources and an oxygen plasma source. A high throughput approach was used for systematic compositional and structural characterization and the screening of the dielectric and ferroelectric properties. The perovskite (Bi,Na)TiO{sub 3}–BaTiO{sub 3} phase with a Ba concentration near the morphotropic phase boundary (ca. 6 at.%) exhibited a relative dielectric permittivity of 180, a loss tangent of 0.04 and remnant polarization of 19 μC/cm{sup 2}. Compared to published data, observed remnant polarization is close to that known for epitaxially grown films but higher than the values reported for polycrystalline films. The high throughput methodology and systematic nature of the study allowed us to establish the composition boundaries of the phase with optimal dielectric and ferroelectric characteristics. - Highlights: • Bi{sub 2}O{sub 3}–Na{sub 2}O–TiO{sub 2}–BaO high throughput materials library was deposited using PVD method. • Materials were processed from individual molecular beam epitaxy sources of elements. • High throughput approach was used for structural, dielectric and ferroelectric study. • Composition boundaries of perovskite compounds with optimum properties are reported.

  12. Structural, dielectric and ferroelectric properties of (Bi,Na)TiO3–BaTiO3 system studied by high throughput screening

    International Nuclear Information System (INIS)

    Hayden, Brian E.; Yakovlev, Sergey

    2016-01-01

    Thin-film materials libraries of the Bi 2 O 3 –Na 2 O–TiO 2 –BaO system in a broad composition range have been deposited in ultra-high vacuum from elemental evaporation sources and an oxygen plasma source. A high throughput approach was used for systematic compositional and structural characterization and the screening of the dielectric and ferroelectric properties. The perovskite (Bi,Na)TiO 3 –BaTiO 3 phase with a Ba concentration near the morphotropic phase boundary (ca. 6 at.%) exhibited a relative dielectric permittivity of 180, a loss tangent of 0.04 and remnant polarization of 19 μC/cm 2 . Compared to published data, observed remnant polarization is close to that known for epitaxially grown films but higher than the values reported for polycrystalline films. The high throughput methodology and systematic nature of the study allowed us to establish the composition boundaries of the phase with optimal dielectric and ferroelectric characteristics. - Highlights: • Bi 2 O 3 –Na 2 O–TiO 2 –BaO high throughput materials library was deposited using PVD method. • Materials were processed from individual molecular beam epitaxy sources of elements. • High throughput approach was used for structural, dielectric and ferroelectric study. • Composition boundaries of perovskite compounds with optimum properties are reported.

  13. A study on non-crystalline BiPbSbSrCaCuO and its heat treatment effect

    International Nuclear Information System (INIS)

    Zhang Hong; Wu Hong; Hu Suhui

    1993-01-01

    In this work positron annihilation spectroscopy, X ray diffraction, differential thermal analysis, scanning electron microscopy and ac susceptibility measurement have been used to study non-crystalline Bi-Pb-Sb-Sr-Ca-Cu-O and the effect of heat treatment. The crystallization temperature T c is around 450-470 degree C for investigated materials. There are low temperature and high temperature structure relaxation as in metallic glasses from room temperature to glass temperature. For T>T c in the crystallized multiphase the low n phase can transform to high n phase by reaction diffusion and T c can reach near 110 K by 850 degree C annealing. The positron annihilation characteristics are sensitive to phase transformation and the electron density sampled by positrons in the non-crystal is lower than that in crystallized one. The doping of Pb and Sb together is of benefit to forming of non-crystal but narrows the temperature range of the viscous state

  14. Effect of double layer thickness on magnetoelectric coupling in multiferroic BaTiO3-Bi0.95Gd0.05FeO3 multilayers

    Science.gov (United States)

    Hohenberger, S.; Lazenka, V.; Temst, K.; Selle, S.; Patzig, C.; Höche, T.; Grundmann, M.; Lorenz, M.

    2018-05-01

    The effect of double-layer thickness and partial substitution of Bi3+ by Gd3+ is demonstrated for multiferroic BaTiO3–BiFeO3 2–2 heterostructures. Multilayers of 15 double layers of BaTiO3 and Bi0.95Gd0.05FeO3 were deposited onto (0 0 1) oriented SrTiO3 substrates by pulsed laser deposition with various double layer thicknesses. X-ray diffraction and high resolution transmission electron microscopy investigations revealed a systematic strain tuning with layer thickness via coherently strained interfaces. The multilayers show increasingly enhanced magnetoelectric coupling with reduced double layer thickness. The maximum magnetoelectric coupling coefficient was measured to be as high as 50.8 V cm‑1 Oe‑1 in 0 T DC bias magnetic field at room temperature, and 54.9 V cm‑1 Oe‑1 above 3 T for the sample with the thinnest double layer thickness of 22.5 nm. This enhancement is accompanied by progressively increasing perpendicular magnetic anisotropy and compressive out-of-plane strain. To understand the origin of the enhanced magnetoelectric coupling in such multilayers, the temperature and magnetic field dependency of is discussed. The magnetoelectric performance of the Gd3+ substituted samples is found to be slightly enhanced when compared to unsubstituted BaTiO3–BiFeO3 multilayers of comparable double-layer thickness.

  15. Tunnelling spectroscopy of BaFe{sub 2}As{sub 2}/Au/PbIn thin film junctions

    Energy Technology Data Exchange (ETDEWEB)

    Doering, Sebastian; Schmidt, Stefan; Schmidl, Frank; Tympel, Volker; Grosse, Veit; Seidel, Paul [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena (Germany); Haindl, Silvia; Iida, Kazumasa; Kurth, Fritz; Holzapfel, Bernhard [IFW Dresden, Institut fuer Metallische Werkstoffe, Dresden (Germany)

    2011-07-01

    Tunnelling spectroscopy is an important tool to investigate the properties of iron-based superconductors. In contrast to commonly used point contact Andreev reflection (PCAR) technique, we fabricated hybrid superconductor / normal metal / superconductor (SNS) thin film structures, with tunable barrier thickness and area. For the base electrode we use Ba(Fe{sub 0.9}Co{sub 0.1}){sub 2}As{sub 2} thin films, produced via pulsed laser deposition (PLD). A gold layer was sputtered to form the barrier, while the counter electrode material is the conventional superconductor PbIn with a T{sub c} of 7.2 K. For temperatures below 7.2 K the spectrum shows a subharmonic gap structure (SGS), described by an extended model of Octavio, Tinkham, Blonder and Klapwijk (OTBK), while at higher temperatures the SGS vanishes and an SN-like behaviour can be observed.

  16. Large electrical manipulation of permittivity in BaTiO3 and Pb(Zr,Ti)O3 bimorph heterostructure

    International Nuclear Information System (INIS)

    Ci, Penghong; Liu, Guoxi; Dong, Shuxiang; Zhang, Li

    2014-01-01

    We report a strain-mediated electric field manipulation of permittivity in BaTiO 3 (barium titanate, BT) ceramic by a Pb(Zr,Ti)O 3 (PZT) bimorph. This BT/PZT heterostructure exhibited a relatively large permittivity tunability of BT up to ±10% in a wide frequency range under an electric field of ±4 kV/cm applied to the PZT bimorph. The permittivity tunability is attributed to the strain in BT produced by the PZT bimorph. Calculations of the relationship between permittivity and applied electric field were developed, and corresponded well with measurements. The BT/PZT heterostructure has potential for applications in broadband field tunable smart electronic devices.

  17. Formation pathways in the synthesis and properties of (Tl0.5Pb0.5)(Sr0.9Ba0.1)2Ca2Cu3Oz and (Tl0.5Pb0.5)(Sr0.8Ba0.2)2Ca2Cu3Oz-1223 superconductors

    International Nuclear Information System (INIS)

    Auinger, M; Gritzner, G; Bertrand, Ch; Galez, Ph; Soubeyroux, J-L

    2007-01-01

    The formation pathway of (Tl 0.5 Pb 0.5 )(Sr 0.9 Ba 0.1 ) 2 Ca 2 Cu 3 O z and (Tl 0.5 Pb 0.5 )(Sr 0.8 Ba 0.2 ) 2 Ca 2 Cu 3 O z was studied by neutron and x-ray diffraction. The following reaction pathway was proposed: thallium oxide and lead oxide react with Sr-rich (Sr 1-x Ca x )CuO 2 and Ca-rich (Ca x Sr 1-x )O to form Sr 4 Tl 2 O 7 and (Ca x Sr 1-x )PbO 3 , respectively. The thallate and the plumbate compounds then form the (Tl 0.5 Pb 0.5 )-1212 phase starting at a temperature of 600 deg. C. Finally, between 850 and 900 deg. C, the 1223 phase is formed from (Tl 0.5 Pb 0.5 )-1212 (Ca x Sr 1-x ) 2 CuO 3 and CuO. Parallel experiments to fabricate the (Tl, Pb)-1223 superconductor resulted in specimens with critical temperatures of 117.5 K and 116 K, respectively, and transition widths of 2 K. Differences between the pathways for the formation of Pb-doped, Sr-rich and Pb-free, Ba-rich Tl-1223 superconductors are discussed

  18. Reactor core design optimization of the 200 MWt Pb-Bi cooled fast reactor for hydrogen production

    International Nuclear Information System (INIS)

    Bahrum, Epung Saepul; Su'ud, Zaki; Waris, Abdul; Fitriyani, Dian; Wahjoedi, Bambang Ari

    2008-01-01

    In this study reactor core geometrical optimization of 200 MWt Pb-Bi cooled long life fast reactor for hydrogen production has been conducted. The reactor life time is 20 years and the fuel type is UN-PuN. Geometrical core configurations considered in this study are balance, pancake and tall cylindrical cores. For the hydrogen production unit we adopt steam membrane reforming hydrogen gas production. The optimum operating temperature for the catalytic reaction is 540degC. Fast reactor design optimization calculation was run by using FI-ITB-CHI software package. The design criteria were restricted by the multiplication factor that should be less than 1.002, the average outlet coolant temperature 550degC and the maximum coolant outlet temperature less than 700degC. By taking into account of the hydrogen production as well as corrosion resulting from Pb-Bi, the balance cylindrical geometrical core design with diameter and height of the active core of 157 cm each, the inlet coolant temperature of 350degC and the coolant flow rate of 7000 kg/s were preferred as the best design parameters. (author)

  19. Effect of cooling rate on the transition temperature in Bi-Pb-Sr-Ca-Cu-O system

    International Nuclear Information System (INIS)

    Wang Yugui; Wang Jinsong; Wang Nanlin; Jiao Xinping; Han Guchang; Chen Zhaojia; Wang Keqin; Wu Xiaoguang

    1989-12-01

    The resistance and a.c. susceptibility measurement show that cooling rate of the cast-annealing samples in heat treatment process has some effect on the 110K superconducting phase in Bi-Pb-Sr-Ca-Cu-O system. Rapid quenching of the sample in air from 845 deg C causes oxygen deficiency in lattice and brings about a trifling change of unit cell size along c-axis direction. The d.c. magnetization and specific heat anomaly Δc measurements demostrate that fast cooling rate can reduce the transition temperature of high-T c phase and the lower critical field, and weaken the pinning forces for vertex lines. The peak value of specific heat anomaly of the sample with nominal composition of Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 4.5 O v is still small in comparison with YBa 2 Cu 3 O 7 . From the magnetization curve the authors estimate that the superconducting volume fraction is about 20%

  20. Study of in vivo generators Pb-212/Bi--212 and U-230/Th-226 for alpha radioimmunotherapy

    International Nuclear Information System (INIS)

    Le Du, A.

    2011-01-01

    Alpha-radioimmunotherapy is a promising cancer therapy that uses a-particles vectorized by monoclonal antibody to break down cancerous tumors. The notion of in vivo generator was introduced in 1989 by Leonard Mausner. The concept involves labeling of various molecular carriers (antibodies, peptides, etc) with intermediate half-life generator parents, which after accumulation in the desired tissue generate much shorter half-life daughter radionuclide. This thesis focuses on the study of two in vivo generators potentially interesting for alpha-radioimmunotherapy: Pb-212 / Bi-212 generator and U-230 / Th-226 generator. The first part of this work presents the Pb-212 / Bi-212 generator, two approaches allowing the vectorization. Chelation approach on a protein and an approach by encapsulation in liposomes have been proposed. This last approach appears to be the most interesting. In vitro stability studies have been performed on these labeling. The second part of this work presents the U-230 / Th-226 generator. Studies have first been made to achieve a theoretical model to describe the speciation of Th(IV) in human serum. The efficacy of DTPA as chelating agent for complexation of Th(IV) in human serum could thus be estimated. (author)

  1. Crystal structure and magnetic properties of the Ba3TeCo3P2O14, Pb3TeCo3P2O14, and Pb3TeCo3V2O14 langasites

    DEFF Research Database (Denmark)

    Krizan, J.W.; de la Cruz, C.; Andersen, Niels Hessel

    2013-01-01

    We report the structural and magnetic characterizations of Ba3TeCo3P2O14, Pb3TeCo3P2O14, and Pb3TeCo3V2O14, compounds that are based on the mineral dugganite, which is isostructural to langasites. The magnetic part of the structure consists of layers of Co2+ triangles. Nuclear and magnetic...... structures were determined through a co-refinement of synchrotron and neutron powder diffraction data. In contrast to the undistorted P321 langasite structure of Ba3TeCo3P2O14, a complex structural distortion yielding a large supercell is found for both Pb3TeCo3P2O14 and Pb3TeCo3V2O14. Comparison...... of the three compounds studied along with the zinc analog Pb3TeZn3P2O14, also characterized here, suggests that the distortion is driven by Pb2+ lone pairs; as such, the Pb compounds crystallize in a pyroelectric space group, P2. Magnetic susceptibility, magnetization, and heat capacity measurements were...

  2. Structures and magnetic properties of rare earth double perovskites containing antimony or bismuth Ba{sub 2}LnMO{sub 6} (Ln=rare earths; M=Sb, Bi)

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Shumpei, E-mail: m-nis-s-o@ec.hokudai.ac.jp; Hinatsu, Yukio

    2015-07-15

    A series of double perovskite-type oxides Ba{sub 2}LnMO{sub 6} (Ln=lanthanides; M=Sb, Bi) were synthesized and their structures were studied. The Ln and M are structurally ordered in the rock-salt type at the B-site of the perovskite ABO{sub 3}. For Ba{sub 2}PrBiO{sub 6} and Ba{sub 2}TbBiO{sub 6}, it has been found that the disordering between Ln ion and Bi ion occurs at the B-site of the double perovskite and both the Pr (Tb) and Bi exist in two oxidation state in the same compound from the analysis of the X-ray diffraction and magnetic susceptibility data. Magnetic susceptibility measurements show that all these compounds are paramagnetic and have no magnetic ordering down to 1.8 K. - Graphical abstract: Tolerance factor for Ba{sub 2}LnMO{sub 6} (M=Sb, Bi) plotted against the ionic radius of Ln{sup 3+}. We have found that there is a clear relation between crystal structures and tolerance factors. - Highlights: • The Ln and M ions are structurally ordered in the rock-salt type at the B-site. • The disordering between Pr (Tb) ion and Bi ion occurs at the B-site. • Ba{sub 2}LnMO{sub 6} (M=Sb, Bi) have no magnetic ordering down to 1.8 K.

  3. Electron density distribution in BaPb1−xSbxO3 superconducting oxides studied by double nuclear magnetic resonance methods

    International Nuclear Information System (INIS)

    Piskunov, Yu. V.; Ogloblichev, V. V.; Arapova, I. Yu.; Sadykov, A. V.; Gerashchenko, A. P.; Verkhovskii, S. V.

    2011-01-01

    The effect of charge disorder on the formation of an inhomogeneous state of the electron system in the conduction band in BaPb 1−x Sb x O 3 superconducting oxides is investigated experimentally by NMR methods. The NMR spectra of 17 O are measured systematically, and the contributions from 17 O atoms with different cation nearest surroundings are identified. It is found that microscopic regions with an elevated spin density of charge carriers are formed within two coordination spheres near antimony ions. Nuclei of the superconducting phase of the oxide (regions with an elevated antimony concentration) microscopically distributed over the sample are detected in compounds with x = 0.25 and 0.33. Experiments in which a double resonance signal of the spin echo of 17 O- 207 Pb and 17 O- 121 Sb are measured in the metal phase of BaPb 1−x Sb x O 3 oxides are carried out for the first time. The constants of indirect heteronuclear spin-spin 17 O- 207 Pb interaction are determined as functions of the local Knight shift 207 Ks. The estimates of the constants of the indirect interaction between the nuclei of the nearest neighbors (O-Pb and Pb-Pb atoms) and analysis of evolution of the NMR spectra of 17 O upon a change in the antimony concentration are convincing evidence in favor of the development of a microscopically inhomogeneous state of the electron system in the metal phase of BaPb 1−x Sb x O 3 oxides.

  4. Synthesis and characterization of Sr{sub 1-x}Ba{sub x}Bi{sub 4}Ti{sub 4}O{sub 15} ferroelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Xie Dan; Pan Wei; Shi Hui

    2003-05-25

    Sr{sub 1-x}Ba{sub x}Bi{sub 4}Ti{sub 4}O{sub 15} (SBBT, x=0, 0.2, 0.5, 0.8, 1.0) was prepared by sol-gel method using the salts of strontium (Sr), barium (Ba), bismuth (Bi) and titanium butoxide as sources. The mechanism of hydrolysis and polymetric reaction of precursor solution and the influence of annealing condition on crystal structure and microstructure of SBBT ferroelectric materials were studied by infrared (IR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results of the analysis indicated the formation of stable sol-gel system for SBBT when pH value of the solution was about 3.5. The crystallization temperature of SBBT powder was about 700 deg. C and the particle size was about 100 nm.

  5. Effect of La-substitution on the structure and dielectric properties of BaBi4Ti4O15 ceramics

    International Nuclear Information System (INIS)

    Chakrabarti, A.; Bera, J.

    2010-01-01

    Four-layer Aurivillius compound BaBi 4-x La x Ti 4 O 15 (x = 0.1-1.0) is synthesized by a modified chemical route. X-ray diffraction analysis confirms the formation of single-phase Aurivillius compound. The crystal structure of compound changes from orthorhombic to pseudo-tetragonal at x = 0.5. BaBi 4-x La x Ti 4 O 15 shows typical relaxor behaviour. With increasing La 3+ substitution, shift of T m towards lower temperature and increased relaxor behaviour is observed. The substitution also results in a marked improvement in the remnant polarization and coercive field. The Cole-Cole plots show the presence of two semicircular arcs, suggesting the existence of grain and grain-boundary effects. The dc-conductivity and activation energies for both grain and grain boundary are evaluated. The ceramics with x = 0.3 presents the lowest conductivity among all compositions.

  6. Electronic structure of (La,Sr)2CuO4 and Ba0.6K0.4BiO3

    International Nuclear Information System (INIS)

    Howell, R.H.; Sterne, P.A.; Fluss, M.J.; Kaiser, J.H.; Kitazawa, K.; Kojima, H.; Mosley, W.D.; Dykes, J.W.; Shelton, R.N.

    1995-01-01

    We have measured and calculated the electron-positron momentum distribution of La 2-x Sr x CuO 4 samples for Sr concentrations of 0, 0.1,0.13, and 0.2 and Ba 0.6 K 0.4 BiO 3 . The momentum distribution of all samples contained features derived from the overlap of the positron distribution with the valence electrons. In addition, discontinuities typical of a Fermi surface are seen in the superconducting samples. The form and position of these features are in general agreement with band theory for both La 2-x Sr x CuO 4 and Ba 0.6 K 0.4 BiO 3 . However the evolution of the Fermi surface with doping in La 2-x Sr x CuO 4 differed significantly from expectations based on single electron band theories. (orig.)

  7. The effect of heat treatment on the properties of (Bi,Pb)2Sr2Ca2Cu3Oδ

    International Nuclear Information System (INIS)

    Fetisov, A.V.; Yasnikov, A.G.; Fotiev, A.A.

    1994-01-01

    In synthesis of (Bi,Pb) 2 Sr 2 Ca 2 Cu 2 O δ (2-2-2-3 phase), which is known to belong to a homologous series of bismuth-based superconductors, several routes have been reported to date to yield materials with a high content, around 95% of the main phase. This phase is characterized by the highest superconducting-transition temperature T c among all known high-T c materials. Based on literature data, heat-treatment conditions are expected to affect strongly the T c of the 2-2-2-3 phase, as they do for other high-T c materials. An optimal oxygen content in 2-2-2-3 was presumed to be the deciding factor for attainment of high T c 's. However, heating below ∼ 870 K in air causes no change in oxygen content in the 2-2-2-3 phase. At the same time, it is oxidizing annealing at T c up to 105-110 K. The conclusions found that changes in oxygen content for (Bi,Pb) 2 Sr 2 Ca 2 Cu 2 O δ (2-2-2-3 phase) do not affect T c , which remains unchanged after shor anneals at 370-1020 Kelvin in different atmospheres. In order to obtain high T c 's, it will suffice to exclude long anneals at 1020-1090 Kelvin from the technology. For the 2-2-2-3 phase, a degradation process, which does not change the composition of the phase, is like that for YBa 2 Cu 3 O 6+delta . Proposed is that different structural planes participate in mass exhanage with an atmosphere: (BiO) planes which do not participate to superconductivity, participate in oxygen exchange; and H 2 O and CO 2 penetrate into the CuO 2 planes, which are responsible for superconductivity in the 2-2-2-3 phase

  8. Quantification of the 214 Pb and 214 Bi decay products before and after to reach the secular equilibria with the 226 Ra

    International Nuclear Information System (INIS)

    Quintero P, E.; Rojas M, V.P.; Cervantes N, M.L.; Gaso P, M.I.

    2002-01-01

    In this work a comparison between the 226 Ra concentration and its decay products ( 214 Pb and 214 Bi) in soil samples is presented before and after that the decay mentioned products reach the equilibria with the radium. Moreover, the obtained daughter/father ratio is presented; and the correction factor for the calculus of the 214 Pb and 214 Bi quantification without being necessary to wait until that the secular equilibria has been established. For the quantification of the concentration of the three radionuclides the gamma spectrometry technique was used. (Author)

  9. Tailoring the piezoelectric and relaxor properties of (Bi1/2 Na1/2) TiO3- BaTiO3 via zirconium doping

    DEFF Research Database (Denmark)

    Glaum, Julia; Simons, Hugh; Acosta, Matias

    2013-01-01

    This article details the influence of zirconium doping on the piezoelectric properties and relaxor characteristics of 94(Bi1/2Na1/2)TiO3-6Ba(ZrxTi1-x)O3 (BNT-6BZT) bulk ceramics. Neutron diffraction measurements of BNT-6BZT doped with 0%-15% Zr revealed an electric-field-induced transition...

  10. Electrical conduction in (Na0⋅ 125Bi0⋅ 125 Ba0⋅ 65Ca0⋅)(Nd0 ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 29; Issue 1. Electrical conduction in (Na0.125Bi0.125Ba0.65Ca0.1)(Nd0.065Ti0.87Nb0.065)O3 ceramic. Syed Mahboob G Prasad G S Kumar. Ceramics and Glasses Volume 29 Issue 1 February 2006 pp 35-41 ...

  11. Synthesis and structural characterization of a novel Sillén - Aurivillius bismuth oxyhalide, PbBi3VO7.5Cl, and its derivatives

    Science.gov (United States)

    Charkin, Dmitri O.; Plokhikh, Igor V.; Kazakov, Sergey M.; Kalmykov, Stepan N.; Akinfiev, Victor S.; Gorbachev, Anatoly V.; Batuk, Maria; Abakumov, Artem M.; Teterin, Yury A.; Maslakov, Konstantin I.; Teterin, Anton Yu; Ivanov, Kirill E.

    2018-01-01

    A new Sillén - Aurivillius family of layered bismuth oxyhalides has been designed and successfully constructed on the basis of PbBiO2X (X = halogen) synthetic perites and γ-form of Bi2VO5.5 solid electrolyte. This demonstrates, for the first time, the ability of the latter to serve as a building block in construction of mixed-layer structures. The parent compound PbBi3VO7.5-δCl (δ ≤ 0.05) has been investigated by powder XRD, TEM, XPS methods and magnetic susceptibility measurements. An unexpected but important condition for the formation of the mixed-layer structure is partial (ca. 5%) reduction of VV into VIV which probably suppresses competitive formation of apatite-like Pb - Bi vanadates. This reduction also stabilizes the γ polymorphic form of Bi2VO5.5 not only in the intergrowth structure, but in Bi2V1-xMxO5.5-y (M = Nb, Sb) solid solutions.

  12. Fabrication and characterization of nanostructured Ba-doped BiFeO3 porous ceramics

    Directory of Open Access Journals (Sweden)

    Mostafavi E.

    2016-03-01

    Full Text Available Nanostructured barium doped bismuth ferrite, Bi₀.₈Ba₀.₂FeO₃ porous ceramics with a relatively high magnetic coercivity was fabricated via sacrificial pore former method. X-ray diffraction results showed that 20 wt.% Ba doping induces a structural phase transition from rhombohedral to distorted pseudo-cubic structure in the final porous samples. Moreover, utilizing Bi₀.₈Ba₀.₂FeO₃ as the starting powder reduces the destructive interactions between the matrix phase and pore former, leading to an increase in stability of bismuth ferrite phase in the final porous ceramics. Urea-derived Bi₀.₈Ba₀.₂FeO₃ porous ceramic exhibits density of 4.74 g/cm³ and porosity of 45 % owing the uniform distribution of interconnected pores with a mean pore size of 7.5 μm. Well defined nanostructured cell walls with a mean grain size of 90 nm were observed in the above sample, which is in a good accordance with the grain size obtained from BET measurements. Saturation magnetization decreased from 2.31 in the Bi₀.₈Ba₀.₂FeO₃ compact sample to 1.85 A m²/kg in urea-derived Bi₀.₈Ba₀.₂FeO₃ porous sample; moreover, coercivity increased from 284 to 380 kA/m.

  13. Experimental studies of effect of high current pulse electron and carbon ion beams on high temperature Y-Ba-Cu-O, Bi-Ca-Sr-Cu-O superconductors

    International Nuclear Information System (INIS)

    Korenev, S.A.; Sikolenko, V.V.; Chernakova, A.

    1989-01-01

    This work shows the results of the experiment on the effect of high current electron and carbon ion pulse beams irradiation on High-T c superconductors Y-Ba-Cu-O and Bi-Ca-Cu-O in vacuum (P∼5x10 -5 torr). The parameters of electron beam used in the experiment were: E∼100-300 keV, j e ∼10-1000 A/cm 2 , τ) p ∼300ns. The parameters of carbon ions used in the experiment were: E∼100-300keV j i ∼1-60A/cm, τ p ∼300ns. Experiments had shown the threshold electron beam power density for surface melting in adiabatic heat condition for Y-Ba-Cu-O ceramics up to P 0 >or approx. 10 7 W/cm 2 , and for Bi-Ca-Sr-Cu-O ceramics up to P 0 ∼4x10 6 W/cm 2 . Increasing of critical current in ∼2 times was observed in samples with a melting surface layer. The integral resistance of Y-Ba-Cu-O and Bi-Ca-Sr-Cu-O decreased in ∼2-2.5 times for electron beam irradiated samples and in ∼1.25-1.8 times for ion irradiated samples. Amorphization did not take place and stoichiometry remained after such irradiation. 6 refs.; 2 figs.; 1 tab

  14. Study of the structure, dielectric and ferroelectric behavior of BaBi{sub 4+δ}Ti{sub 4}O{sub 15} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Khokhar, Anita, E-mail: mails4anita@gmail.com, E-mail: goyalphy@gmail.com; Goyal, Parveen K., E-mail: mails4anita@gmail.com, E-mail: goyalphy@gmail.com; Sreenivas, K. [Department of Physics & Astrophysics, University of Delhi, Delhi-110 007 (India); Thakur, O. P. [Electroceramics Group, Solid State Physics Laboratory, Lucknow Road, Delhi 110 054 (India)

    2016-05-23

    The structure and ferroelectric properties of excess bismuth doped barium bismuth titanate BaBi{sub 4+δ}Ti{sub 4}O{sub 15} (δ = 2 - 10 wt.%)) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material with a change in the orthorhombic distortion with varying excess of bismuth content. There is no change in the phase transition temperature (T{sub m}) while the relaxor behaviour has been modified significantly with excess of bismuth doping. Saturated hysteresis loops with high remnant polarization (P{sub r} ~ 12.5  µC/cm{sup 2}), low coercive fields (E{sub c} ~ 26 kV/cm) are measured and a high piezoelectric coefficient (d{sub 33} ~ 29 pC/N) is achieved in poled BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics prepared with up to 8 wt.% of excess bismuth oxide. The improvement in the ferroelectric properties with increase in the excess bismuth content in BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of excess bismuth.

  15. Study of the structure, dielectric and ferroelectric behavior of BaBi_4_+_δTi_4O_1_5 ceramics

    International Nuclear Information System (INIS)

    Khokhar, Anita; Goyal, Parveen K.; Sreenivas, K.; Thakur, O. P.

    2016-01-01

    The structure and ferroelectric properties of excess bismuth doped barium bismuth titanate BaBi_4_+_δTi_4O_1_5 (δ = 2 - 10 wt.%)) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material with a change in the orthorhombic distortion with varying excess of bismuth content. There is no change in the phase transition temperature (T_m) while the relaxor behaviour has been modified significantly with excess of bismuth doping. Saturated hysteresis loops with high remnant polarization (P_r ~ 12.5  µC/cm"2), low coercive fields (E_c ~ 26 kV/cm) are measured and a high piezoelectric coefficient (d_3_3 ~ 29 pC/N) is achieved in poled BaBi_4Ti_4O_1_5 ceramics prepared with up to 8 wt.% of excess bismuth oxide. The improvement in the ferroelectric properties with increase in the excess bismuth content in BaBi_4Ti_4O_1_5 ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of excess bismuth.

  16. FABRICATION AND MECHANICAL PROPERTIES OF Na0.5Bi0.5TiO3–BaTiO3 LEAD-FREE PIEZOELECTRIC CERAMICS

    Directory of Open Access Journals (Sweden)

    PAN YUSONG

    2014-03-01

    Full Text Available Piezoelectric ceramics with 0.94Na0.5Bi0.5TO3–0.06BaTiO3 compositions were fabricated by solid state mixed oxide method and sintered at different temperatures varying from 1050°C to 1150°C to obtain dense ceramics. Phase analysis using X-ray diffraction showed tetragonal perovskite structure of Na0.5Bi0.5TO3 with no BaTiO3 peak detected. The SEM observation revealed that the crystal grain size of the piezoelectric ceramics is on the nano-size dimensions under all the sintering temperature. The study on the compressive mechanical characteristics showed that the compressive strength of the 0.94Na0.5Bi0.5TO3–0.06BaTiO3 piezoelectric ceramics increases with the rise of sintering temperature and sintering time. The change behavior of the compressive strength with the rise of cold pressure presents increasing firstly and then decreases.

  17. Study of SrBi4Ti4O15 (SBTi) dielectric properties of doped PbO

    International Nuclear Information System (INIS)

    Rodrigues Junior, C.A.; Silva Filho, J.M.; Freitas, D.B.; Oliveira, R.G.M.; Sombra, B.; Sales, J.C.

    2012-01-01

    The ceramic SrBi 4 Ti 4 O 15 (SBTI), cation-deficient perovskite A 5 B 4 O 15 , was prepared by the method of solid state reaction and then doped with PbO (in the range 2-10% by weight). The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance spectroscopy at room temperature. The X-ray analysis was performed by the Rietveld refinement. The micrographs of the samples show globular-shaped grains (doped PbO). The dielectric properties: dielectric constant (Κ' or έ) and dielectric loss tangent (tan δ), were measured at room temperature in the frequency range 100 Hz - 1 MHz dielectric properties of these 1 MHz sample doped with 10 % PbO showed the dielectric constant Κ'= 168.34 and dielectric loss tangent tanδ, = 7,1.10 -2 . These results show a good possibility of miniaturization of electronic devices such as capacitors. (author)

  18. Improved ferroelectric and pyroelectric properties of Pb-doped SrBi4Ti4O15 ceramics for high temperature applications

    International Nuclear Information System (INIS)

    Venkata Ramana, E.; Graça, M.P.F.; Valente, M.A.; Bhima Sankaram, T.

    2014-01-01

    Highlights: • Sr 1−x Pb x Bi 4 Ti 4 O 15 (SPBT, x = 0 − 0.4) ceramics were synthesized by soft chemical method. • X-ray diffraction analysis confirmed the formation of bismuth layered structure. • SEM images showed plate like grain morphology with random orientation of plate faces. • Pb-doping resulted in improved ferroelectricity of SrBi 4 Ti 4 O 15 ceramics. • Pb-doped SrBi 4 Ti 4 O 15 exhibited improved pyroelectric properties with high T C . -- Abstract: Ferroelectric properties of Pb-modified strontium bismuth titanate ceramics with chemical formula Sr 1−x Pb x Bi 4 Ti 4 O 15 (x = 0–0.4) were investigated. Polycrystalline ceramics were synthesized by soft chemical method to study the effect of Pb-doping on its physical properties. X-ray diffraction analysis revealed a bismuth layered structure for all the compounds. The doping resulted in an increased tetragonal strain and improved ferroelectric properties. Scanning electron microscope images showed plate like grain morphology with random orientation of platelets. The ferroelectric transition temperature of the ceramics increased systematically from 525 °C to 560 °C with the increase of doping concentration. The piezoelectric coefficient (d 33 ) of the ceramics was enhanced significantly with Pb doping, exhibiting a maximum value of 21.8 pC/N for 40 mol.% Pb-doped SBT. Pyroelectric studies carried out using the Byer–Roundy method indicated that the modified SBT ceramics are promising candidates for high temperature pyroelectric applications

  19. Photovoltaic applications of Cu(Sb,Bi)SM (M = Ag, Pb, Pt)

    Science.gov (United States)

    Tablero, C.

    2017-04-01

    Ternary Cu-(Sb,Bi)-S compounds are great absorbents of the solar radiation with a variety of applications including optoelectronic and photovoltaic applications. The analyses of several quaternary semiconductors derived from Cu-(Sb,Bi)-S materials is carried out using first-principles density-functional theory with orbital-dependent one-electron potentials. These analyses focus on the optoelectronic properties and the potential for solar cells. The optical properties are obtained from first-principles calculations, and split into inter- and intra-shell-species contributions in order to quantify the optical transitions responsible for the absorption. The absorption coefficients are then used as criteria to evaluate the efficiencies of these materials under several sunlight concentrations. The results indicate high energy photovoltaic conversion efficiency because of the large intra shell s-p absorption of the S and Sb or Bi atomic species.

  20. Preparation and characterization of Ag-added Bi1⋅84Pb0 ...

    Indian Academy of Sciences (India)

    Unknown

    microscopy (SEM), electrical transport and a.c. susceptibility techniques. The tube ... high current conductor is high Jc. However, non-textured, porous structure with ... contact resistance studies on Ag added (0–25 wt%) Bi-. 2223 bulk tubes ...

  1. Influence of lanthanum distribution on dielectric and ferroelectric properties of BaBi4-xLaxTi4O15 ceramics

    International Nuclear Information System (INIS)

    Khokhar, Anita; Goyal, Parveen K.; Thakur, O.P.; Shukla, A.K.; Sreenivas, K.

    2015-01-01

    Structural and electrical properties of Lanthanum substituted barium bismuth titanate BaBi 4-x La x Ti 4 O 15 (0 ≤ x ≤ 0.50) ceramics prepared by conventional solid-state reaction method have been investigated. Raman spectra reveals the distribution of lanthanum into the perovskite layers and (Bi 2 O 2 ) 2+ layers of BaBi 4 Ti 4 O 15 ceramics. Room temperature dielectric constant (ε′) increases and considerable reduction in the low frequency (10 −2 to 10 Hz) dielectric losses and in dc conductivity (σ dc ) are seen with lanthanum substitution. A critical La content of x ∼0.20 in BaBi 4-x La x Ti 4 O 15 exhibits a well-defined relaxor behavior as seen from the temperature and frequency dependence of the dielectric parameters ε′(T) and ε″(T). The dielectric data fit well to the modified Curie–Weiss law and the Lorentz-type relation and show increasing diffuseness in the phase transition with increasing La content. The temperature dependence of the characteristic relaxation time obtained from the Cole–Cole model shows a good fit to the non-linear Vogel–Fulcher relation. Improvements in the remnant polarization and a stable piezoelectric charge coefficient are seen up to a La content of x ∼0.20. The observed increase in dielectric loss and σ dc in addition to the diminished ferroelectric/piezoelectric properties for higher La content are explained in terms of changing oxygen vacancy concentration and structural relaxation due to the preferential incorporation of La into the (Bi 2 O 2 ) 2+ layers as evidenced through the Raman spectroscopy. - Highlights: • La distribution in BaBi 4-x La x Ti 4 O 15 ceramics is analyzed through Raman spectroscopy. • Low and a nearly constant loss over wide frequency range (10 −2 –10 7  Hz) obtained. • Critical La content x = 0.2 identified for high resistivity and ideal relaxor characteristics. • Improved P-E hysteresis loops and large remnant polarization measured. • Changes in the

  2. Phases and structural characteristics of high Tc superconducting oxide in (Bi, Pb)-Sr-Ca-Cu-O system

    International Nuclear Information System (INIS)

    Chen, Zuyano; Li, Zhengrong; Qian, Yitai; Zhou, Quien; Cheng, Tingzhu

    1989-01-01

    The various phases, which are responsible for variant maximum d-value including 18.5 angstrom, 15.4 angstrom, 12.2 angstrom, 6.2 angstrom, 3.2 angstrom and possible 9.1 angstrom respectively, observed in high Tc superconducting complex oxide of (Bi,Pb)-Sr-Ca-Cu-O system are reported in this paper according to the result of X-ray diffraction on platelike crystals or crystallites synthesized under different preparation conditions. The phase of tetragonal system with c=3.21 angstrom, a=3.86 angstrom is possible parent structural unit and it is of great significance to the structure constitution of various phases with large lattice parameter c and structural characteristics of superconducting oxide. In view of the above a model of two-dimension stack-up which causes a stack in variant styles along c-axis and constitute various phases with different lattice parameter c is proposed and discussed

  3. Investigation of evaporation characteristics of polonium and its lighter homologues selenium and tellurium from liquid Pb-Bi-eutecticum

    CERN Document Server

    Neuhausen, J; Eichler, B

    2004-01-01

    The evaporation behaviour of polonium and its lighter homologues selenium and tellurium dissolved in liquid Pb-Bi-eutecticum (LBE) has been studied at various temperatures in the range from 482 K up to 1330 K under Ar/H2 and Ar/H2O-atmospheres using γ-ray spectroscopy. Polonium release in the temperature range of interest for technical applications is slow. Within short term (1h) experiments measurable amounts of polonium are evaporated only at temperatures above 973 K. Long term experiments reveal that a slow evaporation of polonium occurs at temperatures around 873 K resulting in a fractional polonium loss of the melt around 1% per day. Evaporation rates of selenium and tellurium are smaller than those of polonium. The presence of H2O does not enhance the evaporation within the error limits of our experiments. The thermodynamics and possible reaction pathways involved in polonium release from LBE are discussed.

  4. A comparative design study of PB-BI cooled reactor cores with forced and natural convection cooling

    International Nuclear Information System (INIS)

    Mizuno, Tomoyasu; Enuma, Yasuhiro; Tanji, Mikio

    2003-01-01

    A comparative core design study is performed on Pb-Bi cooled reactors with forced and natural convection (FC and NC) cooling. Major interests of the study are core performance and core safety features. The designed core concepts with nitride fuel achieve reasonable breeding capability. The results of unprotected event analyses such as UTOP and ULOF show that both of concepts have possible features to withstand unprotected events due to negative reactivity feedback by Doppler effect, control rod drive line expansion, etc. These results lead to a conclusion that both of concepts have possible capability as one of future promising core concepts. A FC cooling core concept has more advantage if fuel recycle viewpoint is emphasized. (author)

  5. Cold texturing of prereacted high-Tc phase Bi(Pb)SrCaCuO under triaxial stresses

    International Nuclear Information System (INIS)

    Langlois, P.; Massat, H.; Suryanarayanan, R.

    1994-01-01

    The alignment of grains in isostatically precompacted samples of prereacted Bi 1.8 Pb 0.4 Sr 2.0 Ca 2.2 Cu 3.0 O 10.3+x powder has been achieved by compressive plastic deformation under isostatic pressure at room temperature. Isostatic pressures were in the range 0.1 to 1. GPa and deformation rates were led up to 57%. Prior to sintering, X-ray diffraction measurements corroborate an expected high-Tc phase purity of nearly 85% and indicate that the as-deformed samples have been textured with the c-axes parallel to the pressing direction whilst a.c. susceptibility measurements ascertain a high transition temperature around 107 K. Intergranular connection does not occur until sintering at 850 C for 80 h and measurements indicate then that the texture has been retained. Superconducting properties themselves show sensitivity to texture through anisotropy-related distinctive irreversibility lines. (orig.)

  6. Peltier-effect in the mixed state of (Bi, Pb)2Sr2Ca2Cu3Oδ

    International Nuclear Information System (INIS)

    Galffy, M.; Hohn, C.; Freimuth, A.

    1994-01-01

    We present measurements of the Peltier-effect in the mixed state of Bi 1.76 Pb 0.24 Sr 2 Ca 2 Cu 3 O δ . The Peltier-coefficient broadens in a magnetic field quite similar to the resistivity and the thermopower. Comparison with the thermopower shows that Onsagers relation holds well. The occurrence of the Peltier-heat in the mixed state well below T c implies that the electric current is accompanied by a large heat current. We show that the vortex contribution to the Peltier-heat is negligibly small. Therefore the heat current has to be attributed to normal quasiparticle excitations. Our results indicate that this quasiparticle contribution to the heat current remains large even at temperatures far below T c . (orig.)

  7. The effect of long annealing on Pb-doped high-Tc Bi-Sr-Ca-Cu-O systems

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, S.; Agnihotry, S.A.; Asthana, P.; Nagpal, K.C.; Saini, K.K.; Chanderkant; Sharma, C.P.; Ekbote, S.N. (National Physical Lab., New Delhi (India))

    1991-01-16

    The lead doped Bi based copper oxide high-Tc superconductors with different nominal compositions and with different annealing time periods are studied. The highest Tc (zero) achieved is 112 K in bulk phase 2223. The varying intensity of the low angle line at 2{theta}{approx equal}4.7deg suggests the gradual formation of the high-Tc phase due to the long annealing of nearly 200 to 250 h. It is also found that the high-Tc phase starts degrading after 250 h of annealing and Tc reduces. The distortion of the 2223 phase is suggested by the broadening of different XRD peaks, also the SEM studies support the above contention. The EDAX studies show no presence of Pb in the crystallites. (orig.).

  8. Development of Bi-base high-temperature Pb-free solders with second-phase dispersion: Thermodynamic calculation, microstructure, and interfacial reaction

    Science.gov (United States)

    Takaku, Yoshikazu; Ohnuma, Ikuo; Kainuma, Ryosuke; Yamada, Yasushi; Yagi, Yuji; Nishibe, Yuji; Ishida, Kiyohito

    2006-11-01

    Bismuth and its alloys are candidates for Pb-free high-temperature solders that can be substituted for conventional Pb-rich Pb-Sn solders (melting point (mp) = 573 583 K). However, inferior properties such as brittleness and weak bonding strength should be improved for practical use. To that end, BiCu-X (X=Sb, Sn, and Zn) Pb-free high-temperature solders are proposed. Miscibility gaps in liquid BiCu-X alloys were surveyed using the thermodynamic database ADAMIS (alloy database for micro-solders), and compositions of the BiCu-X solders were designed on the basis of calculation. In-situ composite solders that consist of a Bi-base matrix with fine intermetallic compound (IMC) particles were produced by gas-atomizing and melt-spinning methods. The interfacial reaction between in-situ composite solders and Cu or Ni substrates was investigated. The IMCs at the interface formed a thin, uniform layer, which is an appropriate morphology for a reliable solder joint.

  9. Preparation of (Bi,Pb)2Sr2Ca2Cu3Ox precursor powders by a modified polyethylene glycol based sol-gel process

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Andersen, N.H.

    2002-01-01

    A modified sol-gel process based on polyethylene glycol has been developed for preparing (Bi,Pb)(2)Sr2Ca2Cu3Ox precursor powders in view of Ag-sheeted tape manufacture. A careful control of the pH and concentration temperature yields an amorphous gel, which can be converted to a fine and extremely...

  10. Ag doped (Bi1.6Pb0.4Sr2CaCu2O8+δ textured rods

    Directory of Open Access Journals (Sweden)

    Díez, J. C.

    2008-06-01

    Full Text Available In this work, superconducting samples of (Bi1.6Pb0.4Sr2CaCu2O8+δ with Ag additions have been studied. (Bi1.6Pb0.4Sr2CaCu2O8+δ + x wt.% Ag (with x = 0, 1 and 3 powders were synthesized using a sol-gel method. The obtained powders were used as precursors to fabricate long textured cylindrical bars through a floating zone melting method. A drastic change on the microstructure has been found when comparing with undoped Bi2Sr2CaCu2O8+δ samples. The results showed that electrical resistivity at room temperature, critical current as well as flexural strength are improved when Ag is added to these Pb doped samples, while critical temperature does not change. On the other hand, it has been found that samples with composition (Bi1.6Pb0.4Sr2CaCu2O8+δ + Ag shown E-I curves with very high sharpness values on the zone of the superconducting to normal transition, reaching n-values (E∼In as high as 45 at 65K.Se han preparado polvos cerámicos de composición (Bi1.6Pb0.4Sr2CaCu2O8+δ + x % Ag en peso (con x = 0, 1 y 3 mediante un proceso sol-gel. Estos polvos se han utilizado para fabricar precursores que se texturaron por medio del método de fusión zonal flotante. Se ha encontrado un gran cambio en la microestructura cuando se compara con muestras de composición pura Bi2Sr2CaCu2O8+δ. Tanto la resistividad eléctrica a temperatura ambiente, como la corriente crítica, así como la resistencia a flexión se mejoran cuando la Ag se adiciona a estas muestras dopadas con Pb, mientras que no se observa cambio en la temperatura crítica. Por otra parte, se ha encontrado que las muestras de composición (Bi1.6Pb0.4Sr2CaCu2O8+δ + Ag presentan una gran pendiente de la curva E-I en la zona de transición entre el estado superconductor y el estado normal. Con estas composiciones, se han encontrado valores de n (E∼In de hasta 45 a 65K.

  11. On the superconducting state in Ba0.6K0.4BiO3 perovskite oxide

    Science.gov (United States)

    Szcześniak, D.; Kaczmarek, A. Z.; Drzazga, E. A.; Szewczyk, K. A.; Szcześniak, R.

    2018-05-01

    We report study on the superconducting state in Ba0.6K0.4BiO3 (BKBO) perovskite oxide, motivated by the inconclusive results on the pairing mechanism in this compound. Our investigations are conducted within the Migdal-Eliashberg formalism, to account for the phonon-mediated superconducting phase. The considered doping level of the discussed material corresponds to the highest critical temperature in this compound, and allows simultaneous analysis of the oxygen isotope effect, for the O16 and O18 isotopes, respectively. We found that such effect is particularly visible for the critical values of the Coulomb pseudopotential (μC⋆) , which equals to 0.18 for the O16 and 0.16 for the O18 isotope in BKBO. Moreover, we determine the size of the superconducting energy band gap (Δg) and note that obtained values (9.68 meV and 9.55 meV for the O16 and O18, respectively) are in good agreement with the experimental predictions which give Δg ∼ 8.68 meV . Finally, we calculate the characteristic dimensionless parameters, such as the zero-temperature energy gap to the critical temperature, the ratio for the specific heat, as well as the ratio associated with the zero-temperature thermodynamic critical field, which suggest occurrence of the strong-coupling and retardation effects within the phonon-mediated scenario in the analyzed material. Where possible the dimensionless ratios are compared to the experimental estimates, and agrees with these which account for the strong-coupling character of the BKBO superconductor.

  12. Sem-EDAX'S Application For Characterization Of Superconductor Material Of (Bi,Pb)-Sr-Ca-Cu-O

    International Nuclear Information System (INIS)

    Handayani, Ari; Wuryanto; Prambudi, Bambang

    1996-01-01

    The microstructure and composition analysis of superconductor material of (Bi,Pb)-Sr-Ca-Cu-O which were synthesized by two different processes (CA and CD Process) by varying the sintering time, i.e. 20,60 and 100 hours were done by using SEM-EDAX method. The standard sample of superconductor material of Bi-Sr-Ca-Cu-O with 1112, 2212 and 2223 phase from Stream has been used for comparison, At 25 kV, the composition analysis showed that, at 20 and 60 hours of sintering, a mixture of phases existed while 100 hours of sintering resulted in a phase close to phase 2223. The result of microstructure observation showed significant differences. At synthesized CA process, 100 hours of sintering gives bigger and clearer platelet microstructure shape than that given by 20 and 60 hours of sintering. Also from the synthesized CD process, the 60 and 100 hours of sintering gives bigger and clearer platelet microstructure shape than that given by the 20 hours of sintering

  13. Current and potential distributions on positive plates with conductive Pb{sub 3}O{sub 4} and BaPbO{sub 3} in their formation and discharge

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yonglang; Liu, Huan [College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350108 (China)

    2008-08-15

    The positive plates with conductive materials, Pb{sub 3}O{sub 4} and BaPbO{sub 3}, in automotive lead-acid batteries were investigated by measuring their current and potential distributions in the course of formation and discharge. It is found that these two conductive materials, especially Pb{sub 3}O{sub 4}, enhance the formation in the initial stage greatly and that they make the current and potential distributions more uniform. In the discharge, the addition of Pb{sub 3}O{sub 4} increases the capacity of the positive plate, but it is unfavorable to the paste curing and causes poor contact between active mass (AM) particles so that the polarization increases greatly at 3 C discharge rate. The BaPbO{sub 3} additive improves not only the formation but also the discharge performance because of its stability in acidic media and at high polarization. The violent charge at high polarization around the plates in the initial formation can lead to poor AM contact and high polarization resistance. (author)

  14. Electronic structure of bismuth in high-temperature superconductor Bi1.6Pb0.4Sr2Ca2.5Cu3.5Oσ

    International Nuclear Information System (INIS)

    Band, I.M.; Egorovm, A.I.; Karazhanova, G.I.

    1990-01-01

    The shifts of K α1 X-ray of bismuth in the HTS-ceramic Bi 1.6 Pb 0.4 Sr 2 Ca 2.5 Cu 5 O σ and Bi 2 O 3 are measured experimentally. It is shown that bismuth is threevalent in the HTS-ceramic. From comparison of the experimental values of shifts with theoretical values calculated within the framework of different modifications of Hartree-Fock method the effective charge at the bismuth atoms in these compounds is determined: q(Bi 2 O 3 )=1.5+2.0, q(Bi 1.6 Pb 0.4 Sr 2 Ca 2.5 Cu 3.5 O σ )= 1.6+2.1. It was suggested, That the Bi significant covalence degree in HTS-ceramic may be a cause of noticeable contribution of the Bi 6p-states in the density of states at Fermi-level. 13 refs.; 1 fig.; 2 tabs

  15. The importance of passive smoking in the accumulation of Pb, Be, Ba, Mg, Ca, Sr in the children adenoid

    Directory of Open Access Journals (Sweden)

    Maria Gerycka

    2014-09-01

    Full Text Available Introduction. The quality of our life is determined by the quality of the air that we breathe. Hence the influence of cigarette smoking and secondary exposure of persons within the smoking environment is significant. Previous studies have confirmed the influence of passive smoking to on the accumulation of given elements in the tonsils. The subject of the study is to determine the importance of ETS exposure for the accumulation of Pb, Be, Ba, Ca, Mg and Sr in the pharyngeal tonsils. Material and methods. The study involved 162 adenoids from boys and girls living in Tychy and Chorzów. exposed and not exposed to passive smoking. All biological samples were subjected to mineralization with nitric acid (V from Merck. The chemical composition of the samples was determined by the ICP – AES method. Results. The statistical analysis of the elements in the tonsils of children exposed and not exposed to ETS is performed taking into account as an additional criterion of distribution the place of residence and gender of the children. Conclusions. There was no significant effect of passive smoking on the increase of the examined metals in the adenoid. However the role of gender and place of residence to the process of accumulation of elements in this organ remains significant.

  16. Preliminary studies of laser-induced breakdown spectrometry for the determination of Ba, Cd, Cr and Pb in toys

    International Nuclear Information System (INIS)

    Godoi, Quienly; Santos, Dario; Nunes, Lidiane C.; Leme, Flavio O.; Rufini, Iolanda A.; Agnelli, Jose A.M.; Trevizan, Lilian C.; Krug, Francisco J.

    2009-01-01

    The performance of laser-induced breakdown spectrometry (LIBS) for the determination of Ba, Cd, Cr and Pb in toys has been evaluated by using a Nd:YAG laser operating at 1064 nm and an Echelle spectrometer with intensified charge-coupled device detector. Samples were purchased in different cities of Sao Paulo State market and analyzed directly without sample preparation. Laser-induced breakdown spectrometry experimental conditions (number of pulses, delay time, integration time gate and pulse energy) were optimized by using a Doehlert design. Laser-induced breakdown spectrometry signals correlated reasonably well with inductively coupled plasma optical emission spectrometry (ICP OES) concentrations after microwave-assisted acid digestion of selected samples. Thermal analysis was used for polymer identification and scanning electron microscopy to visualize differences in crater geometry of different polymers employed for toy fabrication. Results indicate that laser-induced breakdown spectrometry can be proposed as a rapid screening method for investigation of potentially toxic elements in toys. The unique application of laser-induced breakdown spectrometry for identification of contaminants in successive layers of ink and polymer is also demonstrated.

  17. Investigation of corrosion resistance of 18Cr-14NNi-1.5Si austenitic steel in molten PbBi eutectic

    International Nuclear Information System (INIS)

    Rivai, A.K.; Heinzel, H.; Effendi, N.

    2013-01-01

    Full-text: The development of high corrosion resistant materials for the fuel cladding and structural materials in liquid lead-bismuth (Pb-Bi) eutectic environment especially at high temperature is a critical issue for the deployment of LFR (Lead alloy-cooled fast reactor) and ADS (Accelerator driven Transmutation System). Pb-Bi eutectic is a coolant for LFR which is one of the future nuclear reactors in the world (Generation IV reactors), and also a spallation target material and a coolant for ADS. In this study, corrosion test of an austenitic steel was done in COSTA Pb-Bi eutectic corrosion test facility at Pulsed Power and Microwave Technology, Karlsruhe Institute of Technology, Germany. The sample was an 18Cr-14Ni-1.5Si austenitic steel which has been developed in Center For Technology of Nuclear Industry Materials, Indonesian National Nuclear Energy Agency. The test was done in stagnant molten Pb-Bi eutectic at 550 degree Celsius of temperature for about 300 hours with an oxygen concentration of 1 x 10 -6 wt %. The characterization was carried out using OM (Optical Microscope), SEM-EDS (Scanning Electron Microscope and Energy Dispersive X-ray Spectroscope) and AFM (Atomic Force Microscope). The corrosion test result showed the formation of a duplex oxide layer for example an outer iron oxide layer with about 3-3.4 μm in thickness. Furthermore, there was no penetration of Pb-Bi into the bulk of the specimen because of the protection from the protective oxide layer. (author)

  18. Modifications in the rhombohedral degree of distortion and magnetic properties of Ba-doped BiFeO3 as a function of synthesis methodology

    International Nuclear Information System (INIS)

    Rojas-George, G.; Silva, J.; Castañeda, R.; Lardizábal, D.; Graeve, O.A.; Fuentes, L.; Reyes-Rojas, A.

    2014-01-01

    We present an analysis of crystallographic symmetry and the origin of the pseudo-cubic character of doped BiFeO 3 . Specifically, barium-doped bismuth ferrite, Bi 1−x Ba x FeO 3 (x = 0.05, 0.075, 0.1, 0.125), perovskite-type nanoparticles have been synthesized by implementing five modifications to the sol–gel technique (citric acid-assisted sol–gel method, ethylene glycol method, tartaric acid-assisted sol–gel method, polyvinyl alcohol–ethylene glycol method, and EDTA complexing sol–gel method) and their final pseudo-cubic character is discussed. The effect of the carboxylic groups and hydroxyl groups during synthesis is critical to obtain single phase BBFO. Fourier transform infrared spectroscopy and thermogravimetric analysis is used to study the decomposition and thermal behavior of the precursors and their relation to the final nanoparticle characteristics. X-ray diffraction analysis shows a single phase with symmetry changes for four of the five synthesis methodologies employed. Only the EDTA complexing sol–gel method, where EDTA is used as dissolver and chelating agent, is not satisfactory in all concentration ranges. Rietveld results suggest that the degree of distortion of the rhombohedral symmetry in the crystallized BiFeO 3 powders decreases 12% as a result of progressive substitution of Bi 3+ by Ba 2+ and that there is no shift from rhombohedral to tetragonal symmetry. Magnetization properties of samples with a low-distortion rhombohedral structure show higher magnetic saturation and remanent magnetization than samples with high-distortion rhombohedral structure. - Highlights: • Ba–BiFeO 3 : rhombohedral distortion degree is highly affected by the chemical method. • Rietveld results show no shift in BBFO from rhombohedral to tetragonal symmetry. • The low-distortion rhombohedral structure show higher magnetic saturation. • To stabilize a metal complex is necessary a balance between COOH − and OH − groups

  19. Domain walls of BaTiO.sub.3./sub. and PbTiO.sub.3./sub. within Ginzburg-Landau-Devonshire model

    Czech Academy of Sciences Publication Activity Database

    Hlinka, Jiří

    2008-01-01

    Roč. 375, č. 1 (2008), 132-137 ISSN 0015-0193 R&D Projects: GA ČR GA202/06/0411 Institutional research plan: CEZ:AV0Z10100520 Keywords : domain walls * Landau- Ginsburg theory * ferroelectricity * BaTiO 3 * PbTiO 3 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.562, year: 2008

  20. Study of the structural and electrical behavior of Bi(Mg,TiO3 modified (Ba,CaTiO3 ceramics

    Directory of Open Access Journals (Sweden)

    Md. Kashif Shamim

    2016-12-01

    Full Text Available The ability of BaTiO3 to form solid solutions with different dopants (both iso- and aliovalent makes it versatile for various applications. In the present study, (Ba,CaTiO3 (BCT is modified with Bi(MgTiO3 (BMT in search for new lead-free ferroelectric material and improve their properties. For this purpose, BCT acts as a main base material and BMT acts as a modifier to fabricate a multifunctional material. In this study, we report the structural and electrical properties of lead free piezo-ceramics (1−x(Ba0.8Ca0.2TiO3–xBi(Mg0.5Ti0.5O3 with x=0.2, 0.4, 0.5 prepared by solid-state sintering technique. Single perovskite phase with tetragonal structure is obtained for all the compositions, which is reconfirmed by the Raman Spectroscopic study. Dielectric study confirm the temperature stable behavior of the dielectric permittivity values above 300∘C. The dielectric constant value decreases with increase in BMT doping content. Impedance Spectroscopic study confirms non-Debye type dielectric relaxation in the specimen. The Nyquist plot and conductivity studies show the negative temperature coefficient of resistance behavior (NTCR of the samples.

  1. Optical characterization of Tm3+ doped Bi2O3-GeO2-Ga2O3 glasses in absence and presence of BaF2

    Science.gov (United States)

    Han, Kexuan; Zhang, Peng; Wang, Shunbin; Guo, Yanyan; Zhou, Dechun; Yu, Fengxia

    2016-01-01

    In this paper, Two new Bi2O3-GeO2-Ga2O3 glasses (one presence of BaF2) doped with 1mol% Tm2O3 were prepared by melt-quenching technique. Differential thermal analysis (DTA), the absorption, Raman, IR spectra and fluorescence spectra were measured. The Judd–Ofelt intensity parameters, emission cross section, absorption cross section, and gain coefficient of Tm3+ ions were comparatively investigated. After the BaF2 introduced, the glass showed a better thermal stability, lower phonon energy and weaker OH− absorption coefficient, meanwhile, a larger ~1.8 μm emission cross section σem (7.56 × 10−21 cm2) and a longer fluorescence lifetime τmea (2.25 ms) corresponding to the Tm3+: 4F3 → 3H6 transition were obtained, which is due to the addition of fluoride in glass could reduce the quenching rate of hydroxyls and raise the cross-relaxation (3H6 + 3H4 → 3F4 + 3F4) rate. Our results suggest that the Tm3+ doped Bi2O3-GeO2-Ga2O3 glass with BaF2 might be potential to the application in efficient ~1.8 μm lasers system. PMID:27506152

  2. Optical characterization of Tm(3+) doped Bi2O3-GeO2-Ga2O3 glasses in absence and presence of BaF2.

    Science.gov (United States)

    Han, Kexuan; Zhang, Peng; Wang, Shunbin; Guo, Yanyan; Zhou, Dechun; Yu, Fengxia

    2016-08-10

    In this paper, Two new Bi2O3-GeO2-Ga2O3 glasses (one presence of BaF2) doped with 1mol% Tm2O3 were prepared by melt-quenching technique. Differential thermal analysis (DTA), the absorption, Raman, IR spectra and fluorescence spectra were measured. The Judd-Ofelt intensity parameters, emission cross section, absorption cross section, and gain coefficient of Tm(3+) ions were comparatively investigated. After the BaF2 introduced, the glass showed a better thermal stability, lower phonon energy and weaker OH(-) absorption coefficient, meanwhile, a larger ~1.8 μm emission cross section σem (7.56 × 10(-21) cm(2)) and a longer fluorescence lifetime τmea (2.25 ms) corresponding to the Tm(3+): (4)F3 → (3)H6 transition were obtained, which is due to the addition of fluoride in glass could reduce the quenching rate of hydroxyls and raise the cross-relaxation ((3)H6 + (3)H4 → (3)F4 + (3)F4) rate. Our results suggest that the Tm(3+) doped Bi2O3-GeO2-Ga2O3 glass with BaF2 might be potential to the application in efficient ~1.8 μm lasers system.

  3. Characterization of oxygen vacancies and their migration in Ba-doped Pb(Zr0.52Ti0.48)O3 ferroelectrics

    Science.gov (United States)

    Zhang, M. F.; Wang, Y.; Wang, K. F.; Zhu, J. S.; Liu, J.-M.

    2009-03-01

    We investigate in detail the migration kinetics of oxygen vacancies (OVs) in Ba-doped Pb(Zr0.52Ti0.48)O3 (PZT) ferroelectrics by complex impedance spectroscopy. The temperature dependent dc-electrical conductivity σdc suggests that Ba doping into PZT can lower significantly the density of OVs, leading to the distinctly decreased σdc and slightly enhanced activation energy U for the migration of OVs, thus benefiting the polarization fatigue resistance. Furthermore, the polarization fluctuation induced by the relaxation of OVs is reduced by the Ba doping. The Cole-Cole fitting to the dielectric loss manifests strong correlation among OVs, and the migration of OVs appears to be a collective behavior.

  4. HRTEM analysis on nanocrystalline BaTiO3 and PbTiO3: size effects on ferroelectric phase transition temperature

    International Nuclear Information System (INIS)

    Bursill, L.A.; Jiang, B.; Peng, J.L.; Zhong, W.L.; Zhang, P.L.

    1997-01-01

    High-Resolution Transmission Electron Microscopic studies of nanocrystaline particles of BaTiO 3 and PbTiO 3 are reported. There are characteristic differences observed for BaTiO 3 prepared using sol gel (SG) and steric acid gel (SAG) methods. The former exhibit a critical size below which there is no paraelectric/ferroelectric phase transition, whereas BaTiO 3 prepared via the SAG route remained cubic for all conditions. The SAG preparations always showed chemical intergrowth defects whereas the SG preparations were single phase. Atomic resolution images of both varieties showed interesting surface steps and surface relaxations/reconstructions of some facets. Nanocrystalline PbTiO 3 prepared by the SG route remains tetragonal, albeit with decreasing c/a ratio, down to 25nm diameter. HRTEM observations of nanocrystalline PbTiO 3 are also presented. X-ray diffraction, dielectric and Raman scattering measurements also demonstrate pronounced size effects. The relationship between the observed nanostructures and size effects on the physical properties is discussed. 6 refs., 1 tab., 6 figs

  5. Correlation of gamma ray shielding and structural properties of PbO–BaO–P{sub 2}O{sub 5} glass system

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Kulwinder; Singh, K.J., E-mail: kanwarjitsingh@yahoo.com; Anand, Vikas

    2015-04-15

    Highlights: • Transparent glass samples of the system 55PbO{sub x}BaO(45 − x)P{sub 2}O{sub 5} (x = 1 up to 5) have been prepared in the laboratory. • Gamma ray shielding properties improve with the addition of BaO. • Number of non-bridging oxygens decrease with the increase in the content of BaO. • Investigated glass system can be potential candidate as an alternate to conventional radiation shielding ‘concrete’. - Abstract: The presented work has been undertaken to evaluate the applicability of BaO doped PbO-P{sub 2}O{sub 5} glass system as gamma ray shielding material in terms of mass attenuation coefficient and half value layer at photon energies 662, 1173 and1332 keV. A meaningful comparison of their radiation shielding properties has been made in terms of their mass attenuation coefficient and HVL parameters with standard radiation shielding concrete ‘barite’. The density, molar volume, XRD, FTIR, Raman and UV–visible techniques and mechanical properties (by Yamane and Mackenzie's procedure) have been used to study the structural properties of the prepared glass system in order to check the possibility of their commercial utility as alternate to conventional concrete for gamma ray shielding applications.

  6. Photoemission study of absorption mechanisms in Bi2.0Sr1.8Ca0.8La0.3Cu2.1O8+δ, BaBiO3, and Nd1.85Ce0.15CuO4

    International Nuclear Information System (INIS)

    Lindberg, P.A.P.; Shen, Z.; Wells, B.O.; Dessau, D.S.; Ellis, W.P.; Borg, A.; Kang, J.; Mitzi, D.B.; Lindau, I.

    1989-01-01

    Photoemission measurements in the constant-final-state (absorption) mode were performed on three different classes of high-temperature superconductors Bi 2.0 Sr 1.8 Ca 0.8 La 0.3 Cu 2.1 O 8+δ , BaBiO 3 , and Nd 1.85 Ce 0.15 CuO 4 using synchrotron radiation from 20 to 200 eV. Absorption signals from all elements but Ce are identified. The results firmly show that the Bi 6s electrons are more delocalized in BaBiO 3 than in Bi 2.0 Sr 1.8 Ca 0.8 La 0.3 Cu 2.1 O 8+δ , in agreement with the results of band-structure calculations. Differences in the absorption signals due to O and Bi excitations between BaBiO 3 and Bi 2.0 Sr 1.8 Ca 0.8 La 0.3 Cu 2.1 O 8+δ are discussed. Delayed absorption onsets attributed to giant resonances (Ba 4d→4f, La 4d→4f, and Nd 4d→4f transitions) are also reported

  7. Measurement of the mass attenuation coefficients and electron densities for BiPbSrCaCuO superconductor at different energies

    Science.gov (United States)

    Çevik, U.; Baltaş, H.

    2007-03-01

    The mass attenuation coefficients for Bi, Pb, Sr, Ca, Cu metals, Bi2O3, PbO, SrCO3, CaO, CuO compounds and solid-state forms of Bi1.7Pb0.3Sr2Ca2Cu3O10 superconductor were determined at 57.5, 65.2, 77.1, 87.3, 94.6, 122 and 136 keV energies. The samples were irradiated using a 57Co point source emitted 122 and 136 keV γ-ray energies. The X-ray energies were obtained using secondary targets such as Ta, Bi2O3 and (CH3COO)2UO22H2O. The γ- and X-rays were counted by a Si(Li) detector with a resolution of 0.16 keV at 5.9 keV. The effect of absorption edges on electron density, effective atomic numbers and their variation with photon energy in composite superconductor samples was discussed. Obtained values were compared with theoretical values.

  8. Effect of Ba addition on the structural, dielectric and ferroelectric properties of Na0.5Bi0.5TiO3 ceramics

    Directory of Open Access Journals (Sweden)

    Suchanicz J.

    2015-06-01

    Full Text Available Lead-free (Na0.5Bi0.51-xBaxTiO3 (x = 0, 0.04 and 0.06 ceramics were fabricated by conventional solid phase sintering process. X-ray diffraction analysis shows that obtained specimens possess the perovskite structure. The microstructure study shows a dense structure, in good agreement with the relative density determined by the Archimedes method (above 95 %. Electric permittivity anomaly is shifted to low temperature after Ba doping of NBT. The pyroelectric and hysteresis loops measurements show that polarization and coercive field increases and decreases, respectively, after Ba doping of NBT. The obtained results are discussed in terms of ions/lattice imperfections, which create local electromechanical fields. The investigated ceramics are considered to be promising candidates for lead-free electronic materials.

  9. A comparative study on the magnetic and electrical properties of MFe12O19 (M=Ba and Sr)/BiFeO3 nanocomposites

    Science.gov (United States)

    Ahmed, M. A.; Mansour, S. F.; Ismael, H.

    2015-03-01

    M-type hexaferrite (MFe12O19), M=Ba or Sr nanoparticles with hexagonal crystal structure have been successfully synthesized by a citrate auto-combustion method. BiFeO3 (BFO) was prepared by the flash auto-combustion technique. Different nanocomposites were prepared according to the formula [(1-X) MFe12O19+XBiFeO3; M=Ba or Sr, X=0.3, 0.4, 0.5 and 0.6]. The structure and morphology of the obtained nanocomposites have been determined by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). From the results, it is observed that the value of saturation magnetization decreases with increasing BFO content, which was mainly due to the contribution of the volume of the weak-magnetic BFO to the total sample volume.

  10. Quantification of the {sup 214} Pb and {sup 214} Bi decay products before and after to reach the secular equilibria with the {sup 226} Ra; Cuantificacion de los productos de decaimiento {sup 214} Pb y {sup 214} Bi antes y despues de alcanzar el equilibrio secular con el {sup 226} Ra

    Energy Technology Data Exchange (ETDEWEB)

    Quintero P, E.; Rojas M, V.P.; Cervantes N, M.L.; Gaso P, M.I. [Gerencia de Seguridad Radiologica, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    In this work a comparison between the {sup 226} Ra concentration and its decay products ({sup 214} Pb and {sup 214} Bi) in soil samples is presented before and after that the decay mentioned products reach the equilibria with the radium. Moreover, the obtained daughter/father ratio is presented; and the correction factor for the calculus of the {sup 214} Pb and {sup 214} Bi quantification without being necessary to wait until that the secular equilibria has been established. For the quantification of the concentration of the three radionuclides the gamma spectrometry technique was used. (Author)

  11. Improvement of critical current density in thallium-based (Tl, Bi)Sr1.6Ba0.4Ca2Cu3O9-δ superconductors

    International Nuclear Information System (INIS)

    Ren, Z.F.; Wang, C.A.; Wang, J.H.

    1994-07-01

    Epitaxial (Tl,Bi)Sr 1.6 Ba 0.4 Ca 2 Cu 3 O x ((Tl, Bi)-1223) thin films on (100) single crystal LaAlO 3 substrates were synthesized by a two-step procedure. Phase development, microstructure, and relationships between film and substrate were studied by x-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Resistance versus temperature, zero-field-cooled and field-cooled magnetization, and transport critical current density (J c ) were measured. The zero-resistance temperature was 105--111 K. J c at 77 K and zero field was >2 x 10 6 A/cm 2 . The films exhibited good flux pinning properties

  12. Improvement of critical current density in thallium-based (Tl,Bi)Sr1.6Ba0.4Ca2Cu3Ox superconductors

    International Nuclear Information System (INIS)

    Ren, Z.F.; Wang, C.A.; Wang, J.H.

    1994-01-01

    Epitaxial (Tl,Bi)Sr 1.6 Ba 0.4 Ca 2 Cu 3 O x (Tl,Bi)-1223 thin films on (100) single crystal LaAlO 3 substrates were synthesized by a two-step procedure. Phase development, microstructure, and relationships between film and substrate were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Resistance versus temperature, zero-field-cooled and field-cooled magnetization, and transport critical current density (J c ) were measured. The zero-resistance temperature was 105-111 K. J c at 77 K and zero field was > 2 x 10 6 A/cm 2 . The films exhibited good flux pinning properties

  13. Relationship between tolerance factor and temperature coefficient of permittivity of temperature-stable high permittivity BaTiO3–Bi(MeO3 compounds

    Directory of Open Access Journals (Sweden)

    Natthaphon Raengthon

    2016-03-01

    Full Text Available The temperature coefficient of permittivity (TCε of BaTiO3–Bi(MeO3 solid solutions were investigated. It was determined that as the tolerance factor was decreased with the addition of Bi(MeO3, the TCε shifted from large negative values to TCε values approaching zero. It is proposed that the different bonding nature of the dopant cation affects the magnitude and temperature stability of the permittivity. This study suggests that the relationship between tolerance factor and TCε can be used as a guide to design new dielectric compounds exhibiting temperature-stable high permittivity characteristics, which is similar to past research on perovskite and pyrochlore-based microwave dielectrics.

  14. Electric field induced lattice strain in pseudocubic Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-modified BaTiO{sub 3}-BiFeO{sub 3} piezoelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Ichiro, E-mail: ifujii@rins.ryukoku.ac.jp [Department of Materials Chemistry, Ryukoku University, Otsu, Shiga 520-2194 (Japan); Iizuka, Ryo; Ueno, Shintaro; Nakashima, Kouichi; Wada, Satoshi [Interdisciplinary Graduate School of Medical and Engineering, University of Yamanashi, Kofu, Yamanashi 400-8510 (Japan); Nakahira, Yuki; Sunada, Yuya; Magome, Eisuke; Moriyoshi, Chikako; Kuroiwa, Yoshihiro [Department of Physical Science, Hiroshima University, Higashihiroshima, Hiroshima 739-8526 (Japan)

    2016-04-25

    Contributions to the piezoelectric response in pseudocubic 0.3BaTiO{sub 3}-0.1Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-0.6BiFeO{sub 3} ceramics were investigated by synchrotron X-ray diffraction under electric fields. All of the lattice strain determined from the 110, 111, and 200 pseudocubic diffraction peaks showed similar lattice strain hysteresis that was comparable to the bulk butterfly-like strain curve. It was suggested that the hysteresis of the lattice strain and the lack of anisotropy were related to the complex domain structure and the phase boundary composition.

  15. The off-stoichiometric Bi1.8Pb0.3Sr2Ca2Cu3.3Ox target for thin films

    International Nuclear Information System (INIS)

    Harabor, A.; Deletter, M.

    1996-01-01

    X-ray diffraction (XRD), EDAX, AC susceptibility and resistivity measurements has been used as characterization methods for the Bi-2223 monophase target with the starting stoichiometry Bi 1.8 Pb 0.3 Sr 2 Ca 2 Cu 3.3 O x . Pressure parameter is playing an important role in obtaining good superconducting properties for this compound. Critical currents and activation energy has been calculated from susceptibility and magnetoresistivity curves, respectively. The results could be interpreted in terms of TAPS and TAFF models. (orig.)

  16. Effect of Substitutional Pb Doping on Bipolar and Lattice Thermal Conductivity in p-Type Bi0.48Sb1.52Te₃.

    Science.gov (United States)

    Kim, Hyun-Sik; Lee, Kyu Hyoung; Yoo, Joonyeon; Youn, Jehun; Roh, Jong Wook; Kim, Sang-Il; Kim, Sung Wng

    2017-07-06

    Cation substitutional doping is an effective approach to modifying the electronic and thermal transports in Bi₂Te₃-based thermoelectric alloys. Here we present a comprehensive analysis of the electrical and thermal conductivities of polycrystalline Pb-doped p-type bulk Bi 0.48 Sb 1.52 Te₃. Pb doping significantly increased the electrical conductivity up to ~2700 S/cm at x = 0.02 in Bi 0.48-x Pb x Sb 1.52 Te₃ due to the increase in hole carrier concentration. Even though the total thermal conductivity increased as Pb was added, due to the increased hole carrier concentration, the thermal conductivity was reduced by 14-22% if the contribution of the increased hole carrier concentration was excluded. To further understand the origin of reduction in the thermal conductivity, we first estimated the contribution of bipolar conduction to thermal conductivity from a two-parabolic band model, which is an extension of the single parabolic band model. Thereafter, the contribution of additional point defect scattering caused by Pb substitution (Pb in the cation site) was analyzed using the Debye-Callaway model. We found that Pb doping significantly suppressed both the bipolar thermal conduction and lattice thermal conductivity simultaneously, while the bipolar contribution to the total thermal conductivity reduction increased at high temperatures. At Pb doping of x = 0.02, the bipolar thermal conductivity decreased by ~30% from 0.47 W/mK to 0.33 W/mK at 480 K, which accounts for 70% of the total reduction.

  17. Analyzing power measurements for 209Bi(n,n) at 6 and 9 MeV and consistent dispersive optical-model analyses for n+209Bi and n+208Pb from -20 to +80 MeV

    International Nuclear Information System (INIS)

    Weisel, G.J.; Tornow, W.; Howell, C.R.; Felsher, P.D.; AlOhali, M.; Roberts, M.L.; Das, R.K.; Walter, R.L.; Mertens, G.

    1996-01-01

    High-accuracy measurements of A y (θ) data for elastic scattering for n+ 209 Bi have been performed at 6 and 9 MeV. The data are incorporated into a large database of σ(θ), A y (θ), and σ T for n+ 209 Bi covering the energy range 1.0 endash 80 MeV. A complementary database is constructed for n+ 208 Pb and a dispersive optical-model analysis is performed for both scattering systems while constraining many of the parameters to be identical for both systems. A good representation of both databases is obtained with conventional geometry and spin-orbit parameters. The 208 Pb model predicts quite well the measured energies of valence single-particle and single-hole bound states. Occupation probabilities and spectroscopic factors for the same bound states are also calculated. Finally, a fully constrained model is presented in which the only differences between the n+ 208 Pb and the n+ 209 Bi systems are the Fermi energy and the isospin dependence in the real volume potential. copyright 1996 The American Physical Society

  18. Study of fission reactions induced by 4,6He and 7Li beams on 209Bi and 208Pb targets

    Directory of Open Access Journals (Sweden)

    Lukyanov S.M.

    2013-12-01

    Full Text Available Study of fission reactions induced by 4,6He and 7Li beams on 209Bi and 208Pb targets, leading to the production of 210,212A compound nuclei, was performed. It was shown that the fission excitation functions for the three reactions 4,6He + 209Bi and 7Li + 208Pb had similar behavior within the experimental error for a broad range of energy. More likely, halo structure of 6He is not reflected on the fission reaction mechanism. Otherwise, a large value of the fusion cross section was observed so far, as it could be expected in the case of weakly bound character of 6He projectile.

  19. Influence of B4C-doping and high-energy ball milling on phase formation and critical current density of (Bi,Pb)-2223 HTS

    Science.gov (United States)

    Margiani, N. G.; Mumladze, G. A.; Adamia, Z. A.; Kuzanyan, A. S.; Zhghamadze, V. V.

    2018-05-01

    In this paper, the combined effects of B4C-doping and planetary ball milling on the phase evolution, microstructure and transport properties of Bi1.7Pb0.3Sr2Ca2Cu3Oy(B4C)x HTS with x = 0 ÷ 0.125 were studied through X-ray diffraction (XRD), scanning electron microscopy (SEM), resistivity and critical current density measurements. Obtained results have shown that B4C additive leads to the strong acceleration of high-Tc phase formation and substantial enhancement in Jc. High-energy ball milling seems to produce a more homogeneous distribution of refined doped particles in the (Bi,Pb)-2223 HTS which results in an improved intergranular flux pinning and better self-field Jc performance.

  20. Band structure of metallic pyrochlore ruthenates Bi2Ru2O7 and Pb2Ru2O/sub 6.5/

    International Nuclear Information System (INIS)

    Hsu, W.Y.; Kasowski, R.V.; Miller, T.; Chiang, T.

    1988-01-01

    The band structure of Bi 2 Ru 2 O 7 and Pb 2 Ru 2 O/sub 6.5/ has been computed self-consistently from first principles for the first time by the pseudofunction method. We discover that the 6s bands of Bi and Pb are very deep and unlikely to contribute to the metallic behavior as previously believed. The unoccupied 6p bands, however, are only several eV above the Fermi energy and are mixed with the Ru 4d band at the Fermi surface via the framework O atoms, leading to band conduction and delocalized magnetic moments. The predicted location of the 6s bands and the location and width of the O 2p band are confirmed by synchrotron radiation and ultraviolet electron spectroscopy of single crystals

  1. Rapid formation of the 110 K phase in Bi-Pb-Sr-Ca-Cu-O through freeze-drying powder processing

    International Nuclear Information System (INIS)

    Song, K.H.; Liu, H.K.; Dou, S.X.; Sorrell, C.C.

    1990-01-01

    This paper reports three techniques for processing Bi-Pb-Sr-Ca-Cu-O (BPSCCO) powders investigated: dry-mixing, sol-gel formation, and freeze-drying. It was found that sintering for 120 h at 850 degrees C is required to form nearly single-phase (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10-y by dry-mixing, whereas sintering for 30 h at 840 degrees C was sufficient to form the 110 K (2223) phase when freeze-drying was used. The sol-gel route was found to be intermediate in efficiency between these two techniques. Freeze-drying provided highly reactive, intimately mixed, and carbon-free precursors. The presence of carbonates in the uncalcined powders was the major cause of phase segregation and sluggishness of the 110 K phase formation

  2. Relaxation dynamics of lead-free (Na{sub 1/2}Bi{sub 1/2})TiO{sub 3}–BaTiO{sub 3} single crystals studied by Brillouin scattering

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byoung Wan [Department of Physics, Hallym University, Chuncheon, Gangwondo 24252 (Korea, Republic of); Ko, Jae-Hyeon, E-mail: hwangko@hallym.ac.kr [Department of Physics, Hallym University, Chuncheon, Gangwondo 24252 (Korea, Republic of); Li, Xiaobing; Luo, Haosu [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2016-10-01

    The acoustic properties of 0.95(Na{sub 1/2}Bi{sub 1/2})TiO{sub 3}–0.05BaTiO{sub 3} (NBT–0.05BT) single crystals were investigated in a hypersonic frequency range and compared to those of archetypal relaxor Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} (PMN). Temperature dependences of the Brillouin frequency shift of the longitudinal acoustic (LA) mode, as well as its half width, of NBT–5%BT and PMN exhibited diffuse and broad anomalies over a wide temperature range, which were related to the softening of the sound velocity and substantial increase in the hypersonic damping toward the dielectric maximum temperature. These broad acoustic anomalies of unpoled NBT–0.05BT suggest the existence of noncentrosymmetric polar nanoregions in the paraelectric phase which do not evolve into a long-range ferroelectric order. The calculated relaxation times of NBT–0.05BT exhibited much longer values compared to those of PMN, which suggests that the size of polar nanoregions of NBT–0.05BT is larger than that of PMN.

  3. Structural, electrical and multiferroic characteristics of thermo-mechanically fabricated BiFeO3-(BaSr)TiO3 solid solutions

    Science.gov (United States)

    Behera, C.; Choudhary, R. N. P.; Das, Piyush R.

    2018-05-01

    A solid solution consisting of two perovskite compounds (BiFeO3 and (BaSr)TiO3) of chemical composition (Bi1/2Ba1/4Sr1/4)(Fe1/2Ti1/2)O3 has been fabricated in the low dimensional regime by thermo-mechanical (ball milling and heating) approach. The effect of particle size on the structural, micro-structural, relative permittivity, switching (ferroelectric and magnetic) and conduction phenomena of the material has been studied using various experimental techniques such as x-rays diffraction, transmission and scanning electron microscopy, ferroelectric and magnetic hysteresis, dynamic magneto-electric coupling measurement and impedance spectroscopy techniques. All the above extracted properties are found to be particle size dependent. The first order magneto-electric coupling constant is found to be 2.56, 6.6 and 8.7 mV cm‑1.Oe for 30, 60 and 90 h milled calcined (hmc) sample respectively. As the above micro/nano-material with different particle size, has a high relative dielectric constant and low tangent loss, it can be used for some multifunctional devices including capacity energy storage device in nano-electronics.

  4. Study and characterization of the BBT (BaBi4Ti4O15) ceramic added with 1 wt. % Nb2O5

    International Nuclear Information System (INIS)

    Silva, P.M.O.; Sales, A.J.M.; Freitas, D.B.; Oliveira, R.G.M.; Sombra, A.S.B.; Sales, J.C.

    2012-01-01

    This study aims to synthesize and characterize the ceramic BBT (BaBi 4 TI 4 O 15 ) doped with 1% by mass of the densification Nb2O5 to improve the products. The phase of the BBT has been found by solid state reaction. The mixed oxides starting processed by high-energy milling in planetary mill reactor polymer and spheres of zirconia and calcined at 850°C/3h. Later, 'bulks' prepared with the calcined powder were sintered at 950°C/3h. The calcined powder was characterized by X-ray diffraction data and refined by the beta 3.2 DBWSTools program using the Rietveld method. The grain morphology and distribution of pores on the surface of the 'bulks' were analyzed by Scanning Electron Microscopy. The result confirmed the refined to obtain the single phase with tetragonal structure BaBi 4 TI 4 O 15 density of 5.088 g/cm3 calculated in the unit cell. SEM analysis by SEM showed improved densification of the doped. (author)

  5. Using barium alkoxide for sol-gel-preparation of BaTiO sub 3

    Energy Technology Data Exchange (ETDEWEB)

    Limmer, G.; Buerke, H.; Kohl, R.; Tomandl, G. (Erlangen-Nuernberg Univ., Erlangen (Germany, F.R.). Inst. fuer Werkstoffwissenschaften)

    1989-01-01

    For producing multilayer ceramics there exists a demand for low firing temperatures. This would allow the use of cheaper electrode materials. Pure BaTiO{sub 3} usually sinters in the range of 1350deg C to 1400deg C and shows a coarse-grained microstructure. Therefore the use of sintering aids, like Pb, Bi-compounds, is necessary. Our aim is to synthesize highly sinteractive BaTiO{sub 3} powders to avoid the usage of sintering aids. (orig.).

  6. Characteristic of the flux pinning at intergrain boundaries in bulk Bi-Pb-Sr-Ca-Cu-O superconductors

    International Nuclear Information System (INIS)

    Wang Yugui; Yang Yu; Xiong Xiaozhong; Yuan Songliu; Wang Shunxi

    1991-02-01

    The magnetization measurement shows that there are two kinds of different intergrain boundaries in the sintered Bi 1.8 Pb 0.34 Sr 1.86 Ca 2 Cu 3 O y superconductors. One has nearly no pinning force for flux line, the other can trap some flux line in the low field range where a pinning current may be sustained. When the applied field is removed, most of the remanent magnetization comes from the intergrain boundaries. The area of hysteresis loop at low field and the remanent magnetization for the cold-pressed bulk samples are significantly increased. Cold pressing results in aligning the grain orientation and raising the packing density, both of which enhanced intergrain coupling. The J c value of 1040 A/cm 2 at H = 0 and 150 A/cm 2 at H = 1 k Oe are obtained. The flux creep along the intergrain boundaries and the pinning potential energy U 0 for the coldpressed samples are also discussed

  7. Mechanical properties of Bi,Pb(2223) single filaments and Ic(ε) behaviour in longitudinally strained tapes

    International Nuclear Information System (INIS)

    Passerini, Reynald; Dhalle, Marc; Seeber, Bernd; Fluekiger, Rene

    2002-01-01

    The Young's modulus and fracture stress of isolated Bi,Pb(2223) filaments were deduced from three-point bending tests performed at different stages of the tapes preparation. These results were introduced in the model describing the evolution of critical current of tapes submitted to a longitudinal strain in view to predict their irreversible strain limit ε irr . These calculated irreversible strain limits were compared to measured values, taken from a set of tapes made with different filling factors and composite matrices. This experiment shows that the predicted irreversible strain limits correspond to the measured ones. Presenting the I c behaviour of highly stressed tapes in a magnetic field, we discuss the evolution of the ratio I strong c0 /I c0 versus strain. This value, representative of the fraction of the critical current attributed to strongly connected grains, increases significantly during the crack formation regime at ε > ε irr . This indicates that mechanically weak links correspond to electromagnetically weak ones. This result is further confirmed by comparing the modulus of rupture obtained in single filaments extracted from tapes with different I c values

  8. Radon and progeny (214Pb and 214Bi) in urban water-supply systems of Sao Paulo State, Brazil

    International Nuclear Information System (INIS)

    Bonotto, Daniel Marcos; Padron-Armada, Priscilla Cardoso

    2008-01-01

    Many water-supply systems in South America utilize the waters of the Guarani aquifer at least as part of their networks. However, there is little present knowledge in Brazil of the factors affecting Rn presence in the water supplied for end-users, despite the economic importance of Guarani aquifer. 222 Rn analyzes of 162 water samples were performed at 8 municipalities in Sao Paulo State, Brazil, with the aim of investigating the major factors affecting its presence in solution. The 222 Rn activity concentration ranged from 0.04 up to 204.9 Bq/L, with three samples exceeding the World Health Organization maximum limit of 100 Bq/L. Aeration was confirmed as the most important factor for Rn release, as expected due to its gaseous nature. Accumulation in pipes and stratification in the water column were other significant factors explaining the data obtained in some circumstances. The Rn daughters 214 Pb and 214 Bi were also determined in a set of selected samples and their presence was directly related to the occurrence of Rn dissolved in water

  9. Mechanical properties of Bi,Pb(2223) single filaments and I sub c (epsilon) behaviour in longitudinally strained tapes

    CERN Document Server

    Passerini, R; Seeber, B; Flükiger, R

    2002-01-01

    The Young's modulus and fracture stress of isolated Bi,Pb(2223) filaments were deduced from three-point bending tests performed at different stages of the tapes preparation. These results were introduced in the model describing the evolution of critical current of tapes submitted to a longitudinal strain in view to predict their irreversible strain limit epsilon sub i sub r sub r. These calculated irreversible strain limits were compared to measured values, taken from a set of tapes made with different filling factors and composite matrices. This experiment shows that the predicted irreversible strain limits correspond to the measured ones. Presenting the I sub c behaviour of highly stressed tapes in a magnetic field, we discuss the evolution of the ratio I sup s sup t sup r sup o sup n sup g sub c sub 0 /I sub c sub 0 versus strain. This value, representative of the fraction of the critical current attributed to strongly connected grains, increases significantly during the crack formation regime at epsilon >...

  10. Spectroscopic features of Ni(2+) ion in PbO-Bi2O3-SiO2 glass system.

    Science.gov (United States)

    Suresh, B; Srinivasa Reddy, M; Siva Sesha Reddy, A; Gandhi, Y; Ravi Kumar, V; Veeraiah, N

    2015-04-15

    Glasses of the composition (30-x)PbO-5Bi2O3-65SiO2: xNiO (with x ranging from 0 to 1.0 mol%) were synthesized. A variety of spectroscopic studies, viz., IR, Raman optical absorption and luminescence properties of these glasses have been carried out as a function of NiO concentration. The analysis of results of all these studies has indicated that the nickel ions occupy both octahedral and tetrahedral positions. However, with the increase of NiO concentration the octahedral occupancy of Ni(2+) ions prevailed over the tetrahedral ions. The luminescence spectra of these glasses have exhibited a broad NIR emission band in region 1100-1500 nm. This band is identified as being due to (3)T2(3F)→(3)A2(3F) octahedral transition of Ni(2+) ions. The luminescence efficiency and cross section have been found to be the highest for the glass containing the highest concentration of NiO. The reasons for such high luminescence efficiency have been discussed in the light of structural variations taking place in the host glass network. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Study on core radius minimization for long life Pb-Bi cooled CANDLE burnup scheme based fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Afifah, Maryam, E-mail: maryam.afifah210692@gmail.com; Su’ud, Zaki [Nuclear Research Group, FMIPA, Bandung Institute of Technology Jl. Ganesha 10, Bandung 40132 (Indonesia); Miura, Ryosuke; Takaki, Naoyuki [Department of Nuclear Safety Engineering, Tokyo City University 1-28-1 Tamazutsumi, Setagaya, Tokyo 158-8557 (Japan); Sekimoto, H. [Emerritus Prof. of Research Laboratory for Nuclear Reactors, Tokyo Inst. of Technology (Japan)

    2015-09-30

    Fast Breeder Reactor had been interested to be developed over the world because it inexhaustible source energy, one of those is CANDLE reactor which is have strategy in burn-up scheme, need not control roads for control burn-up, have a constant core characteristics during energy production and don’t need fuel shuffling. The calculation was made by basic reactor analysis which use Sodium coolant geometry core parameter as a reference core to study on minimum core reactor radius of CANDLE for long life Pb-Bi cooled, also want to perform pure coolant effect comparison between LBE and sodium in a same geometry design. The result show that the minimum core radius of Lead Bismuth cooled CANDLE is 100 cm and 500 MWth thermal output. Lead-Bismuth coolant for CANDLE reactor enable to reduce much reactor size and have a better void coefficient than Sodium cooled as the most coolant for FBR, then we will have a good point in safety analysis.

  12. Specific features of acoustic properties of ceramic Bi1.4Pb0.6Ca2Sr2Cu3Oy

    International Nuclear Information System (INIS)

    Gajduk, A.L.; Fil', V.D.; Burma, N.G.

    1991-01-01

    Anomalies of sound velocity and attenuation, as well as of heat capacity are revealed in the Pb-stabilized Bi ceramics of the composition 2-2-2-3 atare 60 K, which are interpreted as the second-order phase transition. The sensitivity of the anomalies to the quenched magnetic flux is indicative of the magnetic nature of the transition. Similar features also observed at the same temperature in the 1-2-3* type superconducting systems

  13. Structural relaxation in the magnetically treated glass ceramic Bi1.8Pb0.2Sr2CaCu2Ox

    International Nuclear Information System (INIS)

    Alekseenko, V.I.; Volkova, G.K.; Konstanminova, T.E.; Nosolev, I.K.; Popova, I.B.

    1994-01-01

    Structure relaxation in Bi 1.8 Pb 0.2 Sr 2 CaCu 2 O x amorphous glass ceramics after the treatment using weak pulse magnetic field is studied using microindentation, X-ray structure analysis and inner friction techniques. Structure relaxation after substance treatment using pulse magnetic field is detected to occur at room temperature and to result in its strengthening (increase of microhardness-H v ) and in reduction of inner microstress level.9 refs., 4 figs

  14. Effect of Low-Melting Metals (Pb, Bi, Cd, In) on the Structure, Phase Composition, and Properties of Casting Al-5% Si-4% Cu Alloy

    Science.gov (United States)

    Yakovleva, A. O.; Belov, N. A.; Bazlova, T. A.; Shkalei, I. V.

    2018-01-01

    The effect of low-melting metals (Pb, Bi, Cd, In) on the structure, phase composition, and properties of the Al-5% Si-4% Cu alloy was studied using calculations. Polythermal sections have been reported, which show that the considered systems are characterized by the presence of liquid regions and monotectic reactions. The effect of low-melting metals on the microstructure and hardening of base alloy in the cast and heat-treated states has been studied.

  15. Computational study of electronic, optical and thermoelectric properties of X3PbO (X = Ca, Sr, Ba) anti-perovskites

    Science.gov (United States)

    Hassan, M.; Arshad, I.; Mahmood, Q.

    2017-11-01

    We report the structural, electronic, optical and thermoelectric (TE) properties of X3PbO (X = Ca, Sr, Ba) anti-perovskites as a function of X cations belonging to the group IIA. The computations are done by using the most recently introduced modified Becke-Johnson potential. It has been observed that the cubic lattice constant increases as the cations change from Ca to Ba, consequently, the bulk modulus reduces. The bottom of conduction band shows strong hybridization between Pb-6p, O-2p and X-s states, in contrast, valence band maxima are mainly manufactured by Pb-6p states. The anti-perovskites exhibit narrow direct band gap that show an inverse relation to the static real dielectric constants that verifies Penn’s model. In addition, the X cations induced tuning of the absorption edge in the visible and the ultraviolet energy suggest optical device applications. The computed TE parameters have been found sensitive to the X cations and have been demonstrated to be best suited for the TE devices operating at high temperatures.

  16. Bi-doped PbO2 anodes: Electrodeposition and physico-chemical properties

    International Nuclear Information System (INIS)

    Shmychkova, O.; Luk’yanenko, T.; Velichenko, A.; Meda, L.; Amadelli, R.

    2013-01-01

    The influence of bismuth ions on kinetics of lead dioxide electrodeposition from methanesulfonate electrolytes and physico-chemical properties of obtained coatings were studied. Experimental results are consistent with a mechanism previously proposed in the literature for lead dioxide electrodeposition. The presence of bismuth ions in the electrodeposition solution causes a decrease of rate constants of lead dioxide formation due to co-adsorption phenomena. Deposits from solutions containing bismuth ions appear shiny dark grey, and show good adhesion to metal support. SEM images reveal a compact structure with spindle-shaped submicron and nanosized crystals and X-ray diffractograms demonstrated that incorporation of bismuth diminishes the size of crystal particles. Oxygen evolution was investigated to test electrocatalytic activity. It is shown, that oxygen overpotential on modified electrodes is significantly higher than on non-modified PbO 2 -electrode, which depends on bismuth content in deposit and segregation of bismuth that induces surface heterogeneity due to sites with different electroactivity for water oxidation

  17. Radio frequency response of Ag-sheathed (Bi, Pb)2Sr2Ca2Cu3O10+x superconducting tapes

    International Nuclear Information System (INIS)

    Grasso, G.

    2000-01-01

    The response of long (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10 conductors fabricated by the oxide-powder-in-tube method to a radio frequency excitation was investigated while employed as the inductive part of large L-C resonating circuits. After removal of the outer silver sheath, superconducting devices cooled down to 77 K showed superior properties compared to equivalent non-superconducting circuits: Bi-based resonators, conceived for a working frequency in the range between 5 and 17 MHz, presented an improvement of the quality factor by a factor of 20. This result opens new perspectives for the application of Bi-based superconducting materials in the detection of a weak radio frequency signal, as in magnetic resonance imaging. (author)

  18. Safety performance comparation of MOX, nitride and metallic fuel based 25-100 MWe Pb-Bi cooled long life fast reactors without on-site refuelling

    International Nuclear Information System (INIS)

    Su'ud, Zaki

    2008-01-01

    In this paper the safety performance of 25-100 MWe Pb-Bi cooled long life fast reactors based on three types of fuels: MOX, nitride and metal is compared and discussed. In the fourth generation NPP paradigm, especially for Pb-Bi cooled fast reactors, inherent safety capability is necessary against some standard accidents such as unprotected loss of flow (ULOF), unprotected rod run-out transient over power (UTOP), unprotected loss of heat sink (ULOHS). Selection of fuel type will have important impact on the overall system safety performance. The results of safety analysis of long life Pb-Bi cooled fast reactors without on-site fuelling using nitride, MOX and metal fuel have been performed. The reactors show the inherent safety pattern with enough safety margins during ULOF and UTOP accidents. For MOX fuelled reactors, ULOF accident is more severe than UTOP accident while for nitride fuelled cores UTOP accident may push power much higher than that comparable MOX fuelled cores. (author)

  19. Structure, spectra and thermal, mechanical, Faraday rotation properties of novel diamagnetic SeO2-PbO-Bi2O3-B2O3 glasses

    Science.gov (United States)

    Chen, Qiuling; Su, Kai; Li, Yantao; Zhao, Zhiwei

    2018-06-01

    Faraday rotation diamagnetic glass has attracted research attentions in photonics, sensing and magneto optical devices due to their high refractive index, wide transmittance in UV and Fourier transform infrared (FT-IR) range and temperature independent Faraday rotation. Selenite modified heavy metal oxides glasses with composition of xSeO2-(10-x) B2O3-45PbO-45Bi2O3 (x = 0, 1, 5 and 10mol%) and 15%SeO2-40%PbO-45%Bi2O3 have been fabricated by melt-quenching method in present study. The influence of SeO2 on glass forming ability, thermal, mechanical properties and Faraday rotation were evaluated through X-ray Diffraction (XRD), Fourier transforms infrared spectra (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), Vicker's hardness and Verdet constant measurements. XRD spectra reveal that the good vitrification was achieved for glass with SeO2 amounts ≤10% even without B2O3. FT-IR, Raman and XPS spectra ascertain the existence of characteristic vibration of SeO4, SeO3, PbO4, BiO3 and BO3 units. The incorporation of SeO2 increases the connectivity of glassy network by increasing the Tg, thermal stability and mechanical hardness. The small band gap, high polarizable Se4+ ions and isolated SeO3 units contribute to Faraday rotation improvement.

  20. The sorption of 210Pb, 210Bi and 210Po on montmorillonite: a study with emphasis on reversibility aspects and on the effect of the radioactive decay of adsorbed nuclides

    International Nuclear Information System (INIS)

    Ulrich, H.J.; Degueldre, C.

    1993-01-01

    The influence of the ionic strength and of pH on the adsorption/desorption processes of Pb, Bi and Po on montmorillonite has been investigated. For Pb, a strong dependence of the adsorption and desorption processes on the ionic strength was observed at pH d ) are measured. They range from 10 3 to 10 5 ml . g -1 for Pb and from 10 4 to 10 7 ml . g -1 for 210 Bi and 210 Po. When adsorption and desorption coefficients are compared, an agreement is found for both adsorption/desorption R d 's of Pb, whereas, for Bi and Po adsorption R d 's were several orders of magnitude lower than those obtained for desorption. The chemical activities of free Bi and Po in the liquid phase are limited by the formation of Bi and Po-colloids prior to the sorption step. This fact could explain the differences in the R d values. While the adsorption of Pb was reversible, only very small amounts of BI and Po could be desorbed from the montmorillonite (quasi-irreversible adsorption). The radioactive decay of adsorbed 210 Pb to 210 Bi, which in turn decays to 210 Po, can lead to significant changes in the desorption behaviour of the daughter nuclides. Whereas the sorption is nearly irreversible if Bi and Po adsorb on montmorillonite from the aqueous phase, they desorb more easily if they are generated by the radioactive decay of adsorbed 210 Pb. The difference in the distribution coefficients R d is approximately one order of magnitude in the case of Po, and more than 2 orders of magnitude in the case of Bi. (orig.)

  1. Phase transformation and impedance spectroscopic study of Ba substituted Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Rekha [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar, 125001, Haryana (India); Ahlawat, Neetu, E-mail: neetugju@yahoo.co.in [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar, 125001, Haryana (India); Agarwal, Ashish; Sanghi, Sujata [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar, 125001, Haryana (India); Sindhu, Monica [Department of Physics, MKJK College, Rohtak, 124001, Haryana (India); Ahlawat, Navneet [Matu Ram Institute of Engineering and Management, Rohtak, 124001, Haryana (India)

    2016-08-15

    (Na{sub 0.5}Bi{sub 0.5}){sub 1−x}Ba{sub x}TiO{sub 3} (x = 0.05, 0.1 and 0.15) ceramics abbreviated as (NBBT1, NBBT2 and NBBT3) are fabricated by conventional ceramic fabrication technique. The analysis of X-ray diffraction pattern of the prepared ceramic performed by Rietveld refinement indicate that crystal structure is rhombohedral for NBBT1, tetragonal for NBBT3 and a phase boundary occurs for NBBT2. Impedance spectroscopy has been employed to study the electrical properties of these ceramics in the frequency range of 10 Hz to 5 MHz and in a temperature range of 303 K–723 K. Frequency and temperature dependent electrical data is analyzed in the framework of conductivity, impedance and electric modulus formalisms. Conductivity spectrum obeys double power law for NBBT1, which is evidenced from two different dispersion regions. While for NBBT2 and NBBT3 only single power law is observed. Relaxation frequency for impedance is found to increase with temperature and obeys Arrhenius relationship with activation energy ≈0.764, 0.527 and 0.471 eV for NBBT1, NBBT2 and NBBT3 respectively. Variation of dielectric constant and tanδ with frequency at different temperatures was analyzed with the help of Maxwell–Wagner and Koop's phenomenogical theory. The presence of peaks in plots showing frequency dependence of tanδ for NBBT2 and NBBT3 indicates relaxor behavior of these compositions. - Highlights: • (Na{sub 0.5}Bi{sub 0.5}){sub 1−x}Ba{sub x}TiO{sub 3} (x = 0.05, 0.1, 0.15) ceramics have been synthesized. • There is change in crystal structure with Ba doping. • NBBT2 and NBBT3 show relaxor behavior.

  2. Diffuse scattering from the liquid-vapor interfaces of dilute Bi:Ga, Tl:Ga, and Pb:Ga alloys

    International Nuclear Information System (INIS)

    Li Dongxu; Jiang Xu; Rice, Stuart A.; Lin Binhua; Meron, Mati

    2005-01-01

    As part of a study of the in-plane wave-vector (q xy ) dependence of the effective Hamiltonian for the liquid-vapor interface, H(q), the wave-vector dependences of diffuse x-ray scattering from the liquid-vapor interfaces of dilute alloys of Bi in Ga, Tl in Ga, and Pb in Ga have been measured. In these dilute alloys the solute component segregates as a monolayer that forms the outermost stratum of the liquid-vapor interfaces, and the density distribution along the normal to the interface is stratified. Over the temperature ranges that the alloy interfaces were studied, the Tl and Pb monolayers exhibit both crystalline and liquid phases while the Bi monolayer is always liquid. The diffuse scattering from the liquid-vapor interfaces of these alloys displays interesting differences with that from the liquid-vapor interface of pure Ga. The presence of a segregated monolayer of solute in the liquid-vapor interface of the alloy appears to slightly suppress the fluctuations in an intermediate wave-vector range in a fashion that preserves the validity of the macroscopic capillary wave model to smaller wavelengths than in pure liquid Ga, and there is an increase in diffuse scattering when the Tl and Pb monolayers melt. The surface intrinsic roughness from fitting the wave-vector dependence of surface tension is 5.0 pm for the Tl:Ga alloy and 1.4 pm for the Bi:Ga alloy. Also, a mode of excitation that contributes to diffuse scattering from the liquid-vapor interface of Pb in Ga, but does not contribute to diffuse scattering from the liquid-vapor interface of Ga, has been identified. It is proposed that this mode corresponds to the separation of the Pb and Ga layers in the regime 1 nm -1 ≤q xy ≤10 nm -1

  3. Development of Pb-rich (Bi, Pb) sub 3 Sr sub 2 Ca sub 2 Cu sub 1 O sub x phase during reformation of lead doped 2223 superconducting phase from melt quenched glass. [BiPbSrCaCuO

    Energy Technology Data Exchange (ETDEWEB)

    Oezkan, N; Glowacki, B A [IRC in Superconductivity, Univ. of Cambridge (United Kingdom)

    1992-05-01

    The reformation process of the lead doped superconducting 2223 phase from the melt quenched glass was investigated. It was shown that during the crystallisation of the glass a new lead rich phase, Bi{sub 0.5}Pb{sub 3}Sr{sub 2}Ca{sub 2}Cu{sub 1}O{sub x}, was formed and severe copper segregation was observed. The volume fraction of the high Tc 2223 phase increased with annealing time for an annealing temperature of 840degC. A glass sample annealed at 840degC for 150 h showed two superconducting transitions Tc = 107 K and Tc = 70 K. (orig.).

  4. Modifications in the rhombohedral degree of distortion and magnetic properties of Ba-doped BiFeO{sub 3} as a function of synthesis methodology

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-George, G. [Centro de Investigación en Materiales Avanzados S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, Chih. 31109 (Mexico); Silva, J. [Universidad Autónoma de Ciudad Juárez, Ave. del Charro 450 Norte, Cd. Juárez, Chih. 32310 (Mexico); Castañeda, R.; Lardizábal, D. [Centro de Investigación en Materiales Avanzados S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, Chih. 31109 (Mexico); Graeve, O.A. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Dr. – MC 0411, La Jolla, CA 92093-0411 (United States); Fuentes, L. [Centro de Investigación en Materiales Avanzados S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, Chih. 31109 (Mexico); Reyes-Rojas, A., E-mail: armando.reyes@cimav.edu.mx [Centro de Investigación en Materiales Avanzados S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, Chih. 31109 (Mexico)

    2014-07-01

    We present an analysis of crystallographic symmetry and the origin of the pseudo-cubic character of doped BiFeO{sub 3}. Specifically, barium-doped bismuth ferrite, Bi{sub 1−x}Ba{sub x}FeO{sub 3} (x = 0.05, 0.075, 0.1, 0.125), perovskite-type nanoparticles have been synthesized by implementing five modifications to the sol–gel technique (citric acid-assisted sol–gel method, ethylene glycol method, tartaric acid-assisted sol–gel method, polyvinyl alcohol–ethylene glycol method, and EDTA complexing sol–gel method) and their final pseudo-cubic character is discussed. The effect of the carboxylic groups and hydroxyl groups during synthesis is critical to obtain single phase BBFO. Fourier transform infrared spectroscopy and thermogravimetric analysis is used to study the decomposition and thermal behavior of the precursors and their relation to the final nanoparticle characteristics. X-ray diffraction analysis shows a single phase with symmetry changes for four of the five synthesis methodologies employed. Only the EDTA complexing sol–gel method, where EDTA is used as dissolver and chelating agent, is not satisfactory in all concentration ranges. Rietveld results suggest that the degree of distortion of the rhombohedral symmetry in the crystallized BiFeO{sub 3} powders decreases 12% as a result of progressive substitution of Bi{sup 3+} by Ba{sup 2+} and that there is no shift from rhombohedral to tetragonal symmetry. Magnetization properties of samples with a low-distortion rhombohedral structure show higher magnetic saturation and remanent magnetization than samples with high-distortion rhombohedral structure. - Highlights: • Ba–BiFeO{sub 3}: rhombohedral distortion degree is highly affected by the chemical method. • Rietveld results show no shift in BBFO from rhombohedral to tetragonal symmetry. • The low-distortion rhombohedral structure show higher magnetic saturation. • To stabilize a metal complex is necessary a balance between COOH{sup

  5. The double-well oscillating potential of oxygen atoms in perovskite system Ba(K)BiO sub 3 : EXAFS - analysis results

    CERN Document Server

    Menushenkov, A P; Konarev, P V; Meshkov, A A; Benazeth, S; Purans, J

    2000-01-01

    Temperature-dependent X-ray absorption investigations were made on the Bi L sub 3 -edge in Ba sub 1 sub - sub x K sub x BiO sub 3 with x=0.0, 0.4 and 0.5. For the superconducting samples (x=0.4 and 0.5) it has been found that the local structure differs from the ideal cubic in contrast to the neutron and X-ray diffraction data. The provided analysis of the EXAFS spectra indicates that the oxygen atoms move in double-well potential produced by the existence of two non-equivalent octahedral types of the oxygen environment of bismuth. The vibrations in such a potential lead to modulations of the Bi-O lengths with low frequency which is determined by the soft oxygen octahedron rotation mode frequency. This induces strong electron-phonon interaction and may be the reason for relatively high-temperature transition (T sub c approx 30 K) to the superconducting state.

  6. Effects of Bi(Zn2/3Nb1/3)O3 Modification on the Relaxor Behavior and Piezoelectricity of Pb(Mg1/3Nb2/3)O3-PbTiO3 Ceramics.

    Science.gov (United States)

    Liu, Zenghui; Wu, Hua; Paterson, Alisa; Ren, Wei; Ye, Zuo-Guang

    2017-10-01

    Relaxor lead magnesium niobate (PMN)-based materials exhibit complex structures and unusual properties that have been puzzling researchers for decades. In this paper, a new ternary solid solution of Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 -Bi(Zn 2/3 Nb 1/3 )O 3 (PMN-PT-BZN) is prepared in the form of ceramics, and the effects of the incorporation of BZN into the PMN-PT binary system are investigated. The crystal structure favors a pseudocubic symmetry and the relaxor properties are enhanced as the concentration of BZN increases. The relaxor behavior and the related phase transformations are studied by dielectric spectroscopy. A phase diagram mapping out the characteristic temperatures and various states is established. Interestingly, the piezoelectricity of the PMN-PT ceramics is significantly enhanced by the BZN substitution, with an optimal value of d 33 reaching 826 pC/N for 0.96[0.7Pb(Mg 1/3 Nb 2/3 )O 3 -0.3PbTiO 3 ]-0.04Bi(Zn 2/3 Nb 1/3 )O 3 . This paper provides a better understanding of the relaxor ferroelectric behavior, and unveils a new relaxor-based ternary system as piezoelectric materials potentially useful for electromechanical transducer applications.

  7. Study of heavy metal concentration (As, Ba, Cd, Hg, Pb, Crin water resources and river of Borujerd city in 2008-2009

    Directory of Open Access Journals (Sweden)

    bahram kamarehei

    2010-02-01

    Full Text Available with industrial and economic growth and different material production that humans gained from natural resources for their comfort and walfare, inwardly introduced toxic material and heavy metal entered environment that there created serious problems for themselves and environment. This study accomplished to determine heavy metal concentration (As, Ba, Cd, Hg, Pb, Crin water resources and river of Borujerd city in 2008-2009. Materials and Methods: This descriptive cross-sectional study was conducted to determine heavy metal concentration (As, Ba, Cd, Hg, Pb, Cr in water resources and river of Borujerd city. 54 samples of water were taken from 18 drinking water wells, and also in two times 8 samples of Borujerd river were taken from before and after the city. Then samples carried into the lab and were concentrated ten times using expressed methods and standard methods. Then heavy metal concentration determined by AAP (WFX 130 and results analyzed by SPSS and EXCEL software. Results: Heavy metal concentration average (As, Ba, Cd, Hg, Pb, Cr in drinking water wells were 0. 0, 0. 3222, 0. 0014, 0. 0002, 0. 0077 mg/l respectively. and heavy metal concentration in river water after the city has been increased than before the city. Conclusion: Results indicated that heavy metal concentration average in Borujerd drinking water wells were lower than standard amounts and drinking water wells didn’t pollute with heavy metal. But heavy metal concentration in river water after the city has been increased than the before of it because city waste water enters the city river.

  8. Depth profiles of production yields of natPb(p, xn206,205,204,203,202 Bi reactions using 100-MeV proton beam

    Directory of Open Access Journals (Sweden)

    Oranj Leila Mokhtari

    2017-01-01

    Full Text Available In this study, results of the experimental study on the depth profiles of production yields of 206,205,204,203,202Bi radio-nuclei in the natural Pb target irradiated by a 100-MeV proton beam are presented. Irradiation was performed at proton linac facility (KOMAC in Korea. The target, irradiated by 100-MeV protons, was arranged in a stack consisting of natural Pb, Al, Au foils and Pb plates. The proton beam intensity was determined by activation analysis method using 27Al(p, 3p1n24Na, 197Au(p, p1n196Au, and 197Au(p, p3n194Au monitor reactions and also using dosimetry method by a Gafchromic film. The production yields of produced Bi radio-nuclei in the natural Pb foils and monitor reactions were measured by gamma-ray spectroscopy. Monte Carlo simulations were performed by FLUKA, PHITS, and MCNPX codes and compared with the measurements in order to verify validity of physical models and nuclear data libraries in the Monte Carlo codes. A fairly good agreement was observed between the present experimental data and the simulations by FLUKA, PHITS, and MCNPX. However, physical models and the nuclear data relevant to the end of range of protons in the codes need to be improved.

  9. Investigation on low room-temperature resistivity Cr/(Ba0.85Pb0.15)TiO3 positive temperature coefficient composites

    DEFF Research Database (Denmark)

    He, Zeming; Ma, J.; Qu, Yuanfang

    2009-01-01

    discussed. Using these special processes, the prepared composite with 20 wt% Cr possessed low room-temperature resistivity (2.96 Ω cm at 25 °C) and exhibited PTC effect (resistivity jump of 10), which is considered as a promising candidate for over-current protector when working at low voltage. The grain......Low room-temperature resistivity positive temperature coefficient (PTC) Cr/(Ba0.85Pb0.15)TiO3 composites were produced via a reducing sintering and a subsequent oxidation treatment. The effects of metallic content and processing conditions on materials resistivity–temperature properties were...

  10. Effects of Pb concentration on phase, microstructure and electrical properties of Bi3.25La0.75Ti3O12 ceramics

    International Nuclear Information System (INIS)

    Lawita, P.; Siriprapa, P.; Watcharapasorn, A.; Jiansirisomboon, S.

    2012-01-01

    In this work, effects of Pb-doping concentration on phase, microstructure and electrical properties of bismuth lead lanthanum titanate (Bi 1−x Pb x ) 3.25 La 0.75 Ti 3 O 12 or BPLT ceramics when x = 0, 0.01, 0.03, 0.05, 0.07, 0.09 and 0.1 were investigated. Phase analysis by X-ray diffraction indicated the existence of orthorhombic phase for all BPLT powders and ceramics. Microstructural investigation using scanning electron microscope showed that all ceramics composed mainly of plate-like grains. An increase in PbO doping content reduced not only diameter and thickness of the grains but also density of the ceramics. Electrical conductivity was found to decrease while dielectric constant increased with Pb-doping concentration. Small reduction of remanent polarization and coercive field was observed in Pb-doped samples. - Highlights: ► We prepared bismuth lead lanthanum titanate ceramics by a solid state mixed-oxide method. ► The optimum sintering temperature was found to be 1150 °C. ► BPLT ceramic was identified by X-ray diffraction method to possess an orthorhombic structure. ► All samples shows plate-like morphology with varying grain size and orientation. ► Increasing Pb-doping content tended to decrease electrical conductivity values.

  11. Compatibility of different stainless steels in molten Pb-Bi eutectic at high temperatures

    International Nuclear Information System (INIS)

    Chandra, K.; Kain, Vivekanand; Laik, A.; Sharma, B.P.; Bhattacharya, S.; Debnath, A.K.

    2005-10-01

    Advanced nuclear reactors and the accelerator driven subcritical (ADS) system require the structural materials to be in contact with the molten metals/lead-bismuth eutectic at 400 degC and higher temperatures. One of the primary concerns in using the molten lead-bismuth eutectic (LBE) as a coolant in the primary circuit of these systems is the degradation of structural materials in contact with LBE. An experimental setup has been fabricated to expose the materials in the molten LBE at high temperatures in stagnant condition under inert atmosphere. Samples from five different stainless steels (types 304L, 316L, 403, duplex SS SAF 2205 and super austenitic SS 2RK65) were exposed in this setup at 450 degC for 200h and at 500 degC for 600 and 2100 h under argon atmosphere. A different setup was prepared in which type 316L SS tube in the as-welded condition was exposed in molten LBE at 500 degC for 1200 h in rotating condition. All the samples showed formation of oxide on their surfaces. The thickness and compositional profiles of these oxides analyzed by EPMA confirmed formation of a double layer oxide on type 316L SS. The oxide thickness was highest on SS 403, while it was lowest on 304L and 316L SS. SEM results showed dissolution of materials at the surface in Sandvik 2RK65 and preferential dissolution of austenite phase in duplex SS. None of the stainless steels, except the duplex and the super austenitic stainless steels, showed any localized or selective corrosion. The composition of LBE before and after the exposure tests was analyzed by XRF technique. The result showed presence of Fe, Cr and Ni in the used LBE but these elements were not present in the virgin Pb-Ei alloy. This showed that the corrosion of stainless steels in LBE at temperatures upto 500 degC is due to oxidation and dissolution of alloying elements through the oxide on stainless steels. (author)

  12. Shielded high-T{sub c} (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} (Bi-2223) superconducting tapes

    Energy Technology Data Exchange (ETDEWEB)

    Lelovic, M.; Eror, N.G. [Department of Materials Science, University of Pittsburgh, Pittsburgh, PA (United States); Balachandran, U.; Prorok, B. [Energy Technology Division, Argonne National Laboratory, Argonne, IL (United States); Selvamanickam, V.; Haldar, P. [Intermagnetics General Corporations, Latham, NY (United States); Talvacchio, J.; Young, R. [Science and Technology Center, Northrop Grumman, Pittsburgh, PA (United States)

    1998-11-01

    A new composite tape was fabricated in which the primary function of the central Ag-sheathed (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} (Bi-2223) filaments was to conduct transport current. A YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (Y-123) thin film was deposited on the top of the Ag-sheathed Bi-2223 tape to shield the applied magnetic field and to protect the central Bi-2223 filaments. The critical current densities of the Y-123-coated, Ag-sheathed Bi-2223 tapes were better than those of an uncoated tape. However, the Y-123 thin film exhibited T{sub c} approx.= 72 K and a broad transition region that shifted the effect to lower temperatures. Furthermore, pole figure measurements showed widely spread a,b planes along the rolling direction, indicating high-angle grain boundaries that diminished the magnitude of the effect. Microstructural observations showed platelike grains of Y-123 with fine growth ledges in the thin film that was heat treated, in contrast with the microstructure of an as-coated thin film that showed large twinned grains. From the processing point of view, the results showed that heat treating Y-123 thin film according to the Bi-2223 tape schedule was compatible with and beneficial for Y-123. These preliminary results may provide a basis for further improvements in processing of long-length Bi-2223 tapes for high-field applications. (author)

  13. Synthesis and Characterization of BaFeO3, (Ba,Bi)FeO3, and Related Epitaxial Thin Films and Nanostructures

    Science.gov (United States)

    2009-01-01

    targets were synthesized from BaCO3 (99.997%) and Fe2O3 (99.998%) powders that are crushed and dry-mixed in a high density alumina mortar and pestle set...30 minutes, or dry-mixed a second time with alumina mortar and pestle set. Then the mixed powders were cold pressed into a 1” diameter pellet with...Society of Japan 28, 44 (1970). 19 F. Iga, Y. Nishihara, T. Katayama, K. Murata, and Y. Takeda, Journal of Magnetism and Magnetic Materials 104-07, 1973

  14. Magneto-optical properties BaBi{sub x}La{sub x}Fe{sub 12−2x}O{sub 19} (0.0≤x≤0.5) hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Auwal, I.A. [Department of Chemistry, Fatih University, 34500 B.Çekmece, İstanbul (Turkey); Baykal, A., E-mail: hbaykal@fatih.edu.tr [Department of Chemistry, Fatih University, 34500 B.Çekmece, İstanbul (Turkey); Güner, S. [Department of Physics, Fatih University, 34500 B.Çekmece, İstanbul (Turkey); Sertkol, M. [Department of Physics Engineering, Istanbul Technical University, 34469 Maslak, Istanbul (Turkey); Sözeri, H. [TUBITAK-UME, National Metrology Institute, P.O. Box 54, 41470 Gebze, Kocaeli (Turkey)

    2016-07-01

    BaBi{sub x}La{sub x}Fe{sub (12−2x)}O{sub 19} (0.0≤x≤0.5) hexaferrites were synthesized by solid state synthesis route and the effects of Bi, La substitutions on structural, magnetic and optical properties were investigated. X-ray powder diffraction, Scanning electron microscopy, Vibrating sample magnetometer, and Percent diffuse reflectance spectroscopy were used to study the physical properties. Room temperature specific magnetization (M–H) curves revealed the ferromagnetic nature of all products. The increasing Bi, La compositions increased the magnetic properties at different magnitudes with respect to undoped BaFe{sub 12}O{sub 19} sample. The maximum values of remnant specific magnetization (M{sub r}=30.3 emu/g), extrapolated specific saturation magnetization (M{sub s}=62.12 emu/g), and magneton number (n{sub B}=16.27) were recorded from BaBi{sub 0.2}La{sub 0.2}Fe{sub 11.4}O{sub 19} hexaferrite. The average crystallite size varies in a range of (37.35–51.36) nm. The coercive field (H{sub c}) of undoped hexaferrites is 1180 Oe and increased to maximum 2320 Oe belonging to BaBi{sub 0.4}La{sub 0.4}Fe{sub 11.2}O{sub 19}. Magnetic anisotropy was confirmed as uniaxial and calculated effective anisotropy constants (K{sub eff}) are between 4.27×10{sup 5} Ergs/g and 5.05×10{sup 5} Ergs/g. The high magnitudes of magnetocrystalline anisotropy (H{sub a}) above than 16,200 Oe revealed that all samples are magnetically hard materials. The Tauc plots were drawn to extrapolate the direct optical energy band gap (E{sub g}) of hexaferrites. The E{sub g} values decreased from 1.76 eV to 1.47 eV with increasing Bi, La compositions. - Highlights: • BaBi{sub x}La{sub x}Fe{sub (12−2x)}O{sub 19} (0.0≤x≤0.5) hexaferrites were synthesized by solid state synthesis route. • The E{sub g} values decreased from 1.76 eV to 1.47 eV with increasing Bi, La compositions. • BaBi{sub xx}La{sub xx}Fe{sub 12-2x}O{sub 19} hexaferrites good candidate for potential applications

  15. Novel and facile synthesis of Ba-doped BiFeO{sub 3} nanoparticles and enhancement of their magnetic and photocatalytic activities for complete degradation of benzene in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, Tayyebeh; Lee, Byeong-Kyu, E-mail: bklee@ulsan.ac.kr

    2016-10-05

    Highlights: • An efficient novel visible light photocatalyst was synthesized. • Ba doped BFO showed enhanced surface area, oxygen vacancies, magnetic and photocatalytic activities. • Ba doped BFO can be an economic photocatalyst for benzene degradation. • Complete degradation and high mineralization of benzene were achieved with 60 min irradiation. - Abstract: In this work, Bi{sub 1-x} Ba{sub x} FeO{sub 3} (x = 0.05, 0.1 and 0.2 mol%) multiferroic materials as visible-light photocatalysts were successfully synthesized via a simple and rapid sol-gel method, at a low temperature and with rapid calcination. Ba loading brought about a distorted structure of BiFeO{sub 3} magnetic nanoparticles (BFO MNPs) consisting of small, randomly oriented and non-uniform grains, leading to increased surface area and improved magnetic and photocatalytic activities. Doping of Ba{sup 2+} into pure BFO (Bi{sub 1-x} Ba{sub x} FeO{sub 3}, x = 0.2 mol%) greatly increased magnetic saturation to 3.0 emu/g and significantly decreased the band-gap energy to 1.79 eV, as compared to 2.1 emu/g and 2.1 eV, respectively, for pure BFO. Bi{sub 1-x}Ba {sub x}FeO{sub 3} of x = 0.2 mol% exhibited the greatest photocatalytic degradation effect after 60 min of visible light irradiation, and reached 97% benzene removal efficiency, leading to production of a high concentration of carbon dioxide (CO{sub 2}), with 93% and 82% reductions in chemical oxygen demand (COD) and total organic carbon (TOC), respectively. The identified major intermediate products of photodegradation enabled prediction of the proposed benzene degradation pathway. The enhanced photocatalytic activity of benzene removal is due to both mechanisms, photocatalytic and photo-Fenton catalytic degradation.

  16. High dielectric permittivity in the microwave region of SrBi2Nb2O9 (SBN) added La2O3, PbO and Bi2O3, obtained by mechanical alloying

    Science.gov (United States)

    Rocha, M. J. S.; Silva, P. M. O.; Theophilo, K. R. B.; Sancho, E. O.; Paula, P. V. L.; Silva, M. A. S.; Honorato, S. B.; Sombra, A. S. B.

    2012-08-01

    This paper presents the microwave dielectric properties and a structural study of SrBi2Nb2O9 (SBN) added La2O3, PbO or Bi2O3 obtained by a solid state procedure. High-energy mechanical milling was used to reduce the particle size, which allows for a better shaping of the green body and an increased reactivity. The mechanical milling activation process produced a reduced sintering temperature in the material, decreasing the loss of the volatile elements and controlling the growth of the grain that is produced when a high temperature is required to obtain dense ceramics. The incorporation of La3+, or Pb2+, or Bi3+ of different amounts (0, 3, 5, 10 and 15 wt%) was used to improve the densification without changing the crystal structure, since with a low doping content these ions can occupy the A site of the perovskite blocks; they can also occupy the Bi3+ sites in Bi2O3 layers. A single orthorhombic phase was formed after calcination at 800 °C for 2 h. X-ray diffraction, Fourier transformation, infrared and Raman spectroscopy have been carried out in order to investigate the effects of doping on SBN. The dielectric permittivity (ɛ‧r) and loss in the microwave region (2-4 GHz) of SBN ceramics with additions of Bi2O3, La2O3 and PbO were studied. Higher values of permittivity (ɛr‧ = 154.6) have been obtained for the SBN added La (15 wt%) a lower loss (tg δ = 0.01531) was also achieved in the SBN added La (15 wt%) sample with PVA and TEOS, respectively. The samples that showed the highest dielectric permittivities were all lanthanum doped, all with values of permittivity above 90. A comparative study associated with different types of binders was completed (with glycerin, PVA and TEOS). This procedure allowed us to obtain phases at lower temperatures than usually appear in the literature. The microwave dielectric properties (permittivity and loss) in the region 2-4 GHz, were studied for all samples. The structural and microwave dielectric properties of SBN show a

  17. Ferroelectric properties of sandwich structured (Bi, La)4T3O12/Pb(Zr, Ti)O3/ (Bi, La)4Ti3O12 thin films on Pt/Ti/SiO2/Si substrates

    International Nuclear Information System (INIS)

    Bao Dinghua; Wakiya, Naoki; Shinozaki, Kazuo; Mizutani, Nobuyasu

    2002-01-01

    Sandwich structured (Bi, La) 4 Ti 3 O 12 /Pb(Zr, Ti)O 3 /(Bi, La) 4 Ti 3 O 12 thin films were fabricated on Pt/Ti/SiO 2 /Si substrates, with the intention of simultaneously utilizing the advantages of both (Bi, La) 4 Ti 3 O 12 (BLT) and Pb(Zr, Ti)O 3 (PZT) thin films such as non-fatigue behaviours of BLT and good ferroelectric properties of PZT. Both BLT and PZT layers were prepared by a chemical solution deposition technique. The experiments demonstrated that the sandwich structure showed fatigue-free characteristics at least up to 10 10 switching bipolar pulse cycles under 8 V and excellent retention properties. The sandwich structured thin films also exhibited well-defined hysteresis loops with a remanent polarization (2P r ) of 8.8 μC cm -2 and a coercive field (E c ) of 47 kV cm -1 . The room-temperature dielectric constant and dissipation factor were 210 and 0.031, respectively, at a frequency of 100 kHz. These results suggest that this sandwich structure is a promising material combination for ferroelectric memory applications. (author)

  18. Investigating the effect of multiple grain-grain interfaces on electric transport behavior of [50 wt% BaFe12O19-50 wt% Na0.5Bi0.5TiO3] magnetoelectric nanocomposite system

    Science.gov (United States)

    Pattanayak, Ranjit; Raut, Subhajit; Dash, Tapan; Mohapatra, Soumyaranjan; Muduli, Rakesh; Panigrahi, Simanchala

    2017-05-01

    Polycrystalline [50 wt% BaFe12O19 (BaM)-50 wt% Na0.5Bi0.5TiO3 (NBT)] particulate novel magnetoelectric nanocomposite system was successfully fabricated by solid state reaction technique. The Rietveld refinement of X-ray diffraction pattern was provided the evidence about the pure phase formation of desired nanocomposite system as well as the presence of both ferrimagnetic (FM) BaM & ferroelectric (FE) NBT phases separately. The Field Scanning Electron Micrograph (FESEM) and Scanning Tunneling Electron Micrograph (STEM) explored the information about grain size and connectivity of the composite system. The XPS study was helped to examine the presence of oxygen vacancy (Ov) as well as multi oxidation states of transition metal ions for nanocomposite system. In this report we have systematically examined the conduction mechanism of different interfaces (BaM-BaM, BaM-NBT and NBT-NBT) by the help of complex impedance spectroscopy technique. From our investigation it was observed that, different interfaces activates at different temperature ranges. Due to absence of OV, BaM-NBT interfaces conduction dominants over BaM-BaM interfaces conduction even at room temperature (RT). The mechanism behind the appeared high dielectric loss (tanδ) at RT which was reduced when NBT-NBT interfaces were activates at higher temperature was explained by Maxwell-Wagner type interfacial polarization concept.

  19. The part of soluble and insoluble forms of Pb, Be, Ba, Ca, Mg, Sr in particulate matter and in the pharyngeal tonsils

    Directory of Open Access Journals (Sweden)

    Maria Gerycka

    2014-09-01

    Full Text Available Introduction. Previous studies have confirmed that the pharyngeal tonsil is a good biomarker of exposure due to its position relative to inhaled air so that multiple elements can be accumulated in this organ. The aim of the study is to determine the share of soluble and insoluble compounds of individual elements in suspended particles in the accumulation of Pb, Be, Ba, Sr, Ca,Mg by the pharyngeal tonsils. Material and methods. The content of the analyzed elements is defined in 86 samples of pharyngeal tonsils from children living in Tychy and in 76 samples of pharyngeal tonsils from children living in Chorzów, as well as in the suspended particles in the air occurring in soluble and insoluble form. The specified coefficients k1, k2 present in the equation division allow the indication the greater importance of soluble and insoluble fraction of an element present in the inhaled air. Results. The value of the coefficients in the equation division based on gender confirmed its importance. Conclusions. The values detect area variation in relation to passive smoking in the extent of accumulation of Pb, Be, Ba, Sr, Mg, Ca in pharyngeal tonsils.

  20. Shell model for BaTiO3-Bi(Zn1/2Ti1/2)O3 perovskite solid solutions

    Science.gov (United States)

    Vielma, J.; Jackson, D.; Roundy, D.; Schneider, G.

    2010-03-01

    Even though the composition of BaTiO3-Bi(Zn1/2Ti1/2)O3 perovskite solid solutions is similar to other ferroelectric compounds, the dielectric response is unusual. Results of permittivity measurements as a function of temperature show a diffuse phase transition indicative of a weakly coupled relaxor behavior.footnotetextC. C. Huang and D. P. Cann, J. Appl. Phys. 104, 024117 (2008) To investigate the weakly coupled relaxor behavior in these materials at intermediate length scales we are developing a newly calibrated shell model based on first-principles supercell calculations of both the solid solution and its compositional endpoints. Initial results for its phase diagram will presented.

  1. Microstructures and superconducting properties of Y-Ba-Cu and Bi-Sr-Ca-Cu oxide wires and coils prepared by the explosive compaction technique

    International Nuclear Information System (INIS)

    Hagino, S.; Suzuki, M.; Takeshita, T.; Takashima, K.; Tonda, H.

    1989-01-01

    It has been shown that explosive compaction technique can be used to densify metal, and ceramics powders and their mixtures. The authors discuss how they applied this technique to produce silver sheathed superconducting oxide wires and coils (Y-B-Cu-O and Bi-Sr-Ca-Cu-O). The wires and coils to be compacted were placed into metal tube and the tube was filled with SiC powder as a pressure propagating medium and the tube was compacted by a cylindrically axisymmetric method. The wires and coils compacted were then heat-treated in order to improve grain boundary connections of superconducting oxide crystalline grains. The oxide cores heat-treated were seen to be very dense, and a part of a Y-Ba-Cu oxide coil which was heat-treated optimally was found to have a critical current density higher than 13,000A/cm 2 at 77K

  2. Single crystal growth of 67%BiFeO3-33%BaTiO3 solution by the floating zone method

    Science.gov (United States)

    Rong, Y.; Zheng, H.; Krogstad, M. J.; Mitchell, J. F.; Phelan, D.

    2018-01-01

    The growth conditions and the resultant grain morphologies and phase purities from floating-zone growth of 67%BiFeO3-33%BaTiO3 (BF-33BT) single crystals are reported. We find two formidable challenges for the growth. First, a low-melting point constituent leads to a pre-melt zone in the feed-rod that adversely affects growth stability. Second, constitutional super-cooling (CSC), which was found to lead to dendritic and columnar features in the grain morphology, necessitates slow traveling rates during growth. Both challenges were addressed by modifications to the floating-zone furnace that steepened the temperature gradient at the melt-solid interfaces. Slow growth was also required to counter the effects of CSC. Single crystals with typical dimensions of hundreds of microns have been obtained which possess high quality and are suitable for detailed structural studies.

  3. Single crystal growth of 67%BiFeO 3 -33%BaTiO 3 solution by the floating zone method

    Energy Technology Data Exchange (ETDEWEB)

    Rong, Y.; Zheng, H.; Krogstad, M. J.; Mitchell, J. F.; Phelan, D.

    2018-01-01

    The growth conditions and the resultant grain morphologies and phase purities from floating-zone growth of 67%BiFeO3-33%BaTiO3 (BF-33BT) single crystals are reported. We find two formidable challenges for the growth. First, a low-melting point constituent leads to a pre-melt zone in the feed-rod that adversely affects growth stability. Second, constitutional super-cooling (CSC), which was found to lead to dendritic and columnar features in the grain morphology, necessitates slow traveling rates during growth. Both challenges were addressed by modifications to the floating-zone furnace that steepened the temperature gradient at the melt-solid interfaces. Slow growth was also required to counter the effects of CSC. Single crystals with typical dimensions of hundreds of microns have been obtained which possess high quality and are suitable for detailed structural studies.

  4. Rietveld refinement and dielectric studies of Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3} ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Kaswan, Kavita, E-mail: kaswan.kavita@gmail.com; Agarwal, Ashish; Sanghi, Sujata; Rangi, Manisha; Jangra, Sandhaya; Singh, Ompal [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana (India)

    2016-05-23

    Polycrystalline Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3} ceramic has been synthesized via conventional solid state reaction technique. The Rietveld refinement of x-ray powder diffraction revealed that the sample has a rhombohedral crystal structure (space group R3c). With increase in temperature, the values of dielectric constant (ϵ′) and dielectric loss (tan δ) are found to be increase at different frequencies which may be the result of increase in the number of charge carriers and their mobilities due to the thermal activation. Further the ac conductivity data is analyzed by using Jonscher’s universal power law. The values of frequency exponent ‘s’ lies in the range 0.2 ≤ s ≤ 0.7 and decreases with increase in temperature which can be explained on the basis of CBH (Correlated Barrier Height) model.

  5. Structural and dielectric properties of four - layer Aurivillius - type Ba0.25Sr0.75Bi4Ti4O15 ceramics

    International Nuclear Information System (INIS)

    Goyal, Parveen K.; Khokhar, Anita; Sreenivas, K.

    2013-01-01

    In the present study, a barium strontium bismuth titanate (Ba 0.25 Sr 0.75 Bi 4 Ti 4 O 15 , BSBT) ceramic composition has been prepared by conventional solid-state reaction. In order to study the structure of as synthesized BSBT ceramics, the X-ray powder diffraction (XRD), Raman and FTIR studies have been carried out on the powdered sample. X-ray diffraction analysis confirms the formation of a single phase four-layer Aurivillius-type ceramics that crystallizes in an orthorhombic structure with A2 1 am space group. The dielectric properties of the ceramics have been studied in the temperature range 30 - 600℃ temperature range at various frequencies (100 Hz to 1 MHz). A sharp dielectric anomaly was observed at ∼ 485℃ at all the frequencies corresponding to the ferroelectric to paraelectric phase transition. The ferroelectric behavior is confirmed from the Curie-Weiss law fitting of the dielectric data. (author)

  6. Debye’s temperature and heat capacity for Sr0.15Ba0.85Bi2Nb2O9 relaxor ferroelectric ceramic

    Directory of Open Access Journals (Sweden)

    A. Peláiz-Barranco

    2016-03-01

    Full Text Available A lead-free relaxor ferroelectric, Sr0.15Ba0.85Bi2Nb2O9, was synthesized via solid-state reaction and the temperature-dependence of the heat capacity was measured in a wide temperature range. The dielectric permittivity was also measured between 500Hz and 5MHz in the same temperature range. No anomaly has been detected in the heat capacity curve for the whole temperature range covered in the present experiments, while broad peaks have been observed in the dielectric permittivity with high frequency dispersion. A typical relaxor behavior has been observed from the dielectric analysis. The Debye’s temperature has showed a minimum value near the freezing temperature. The results are discussed considering the spin-glass model and the high frequency dispersion, which has been observed for the studied relaxor system.

  7. Correlation of the superconducting transition to oxygen stoichiometry in single-crystal Ba1-xKxBiO3-y

    Science.gov (United States)

    Mosley, W. D.; Dykes, J. W.; Klavins, P.; Shelton, R. N.; Sterne, P. A.; Howell, R. H.

    1993-07-01

    Temperature-dependent positron-lifetime experiments have been performed from room temperature to 15 K on single crystals of the oxide superconductor Ba1-xKxBiO3-y. Results indicate that the filling of oxygen vacancies has a marked impact on the superconducting properties of this system. Cation defect concentrations were below the detectable limit of positron-annihilation-analysis techniques in this material, which is in sharp contrast to identical studies on polycrystalline samples. We find that the positron lifetime in these electrochemically deposited single crystals is determined by the oxygen stoichiometry of the lattice, but there is no experimental signature of strong positron localization. By performing a subsequent oxygen anneal on the crystals, the superconducting transition is sharpened and the onset is raised. The observed change in positron lifetime associated with this annealing procedure is in quantitative agreement with theory.

  8. Investigation of gamma ray shielding, structural and dissolution rate properties of Bi2O3-BaO-B2O3-Na2O glass system

    Science.gov (United States)

    Dogra, Mridula; Singh, K. J.; Kaur, Kulwinder; Anand, Vikas; Kaur, Parminder; Singh, Prabhjot; Bajwa, B. S.

    2018-03-01

    In the present study, quaternary system of the composition (0.45 + x) Bi2O3-(0.25 - x) BaO-0.15 B2O3-0.15 Na2O (where 0 ≤ x ≤ 0.2 mol fraction) has been prepared by using melt-quenching technique for investigation of gamma ray shielding properties. Mass attenuation coefficients and half value layer parameters have been determined experimentally at 662 keV by using 137Cs source. It has been found that experimental results of these parameters hold good agreement with theoretical values. The density, molar volume, XRD, FTIR, Raman and UV-visible studies have been used to determine structural properties of the prepared glass samples. Dissolution rate of the samples has also been measured to check their utility as long term durable glasses.

  9. Rietveld refinement, dielectric and magnetic properties of Nb modified Bi0.80Ba0.20FeO3 ceramic

    Science.gov (United States)

    Jangra, Sandhaya; Sanghi, Sujata; Agarwal, Ashish; Rangi, Manisha

    2018-05-01

    Bi0.80Ba0.20Fe0.95Nb0.05O3 ceramic has been prepared via conventional solid state reaction method. Structure analysis was carried out by X-ray diffraction (XRD) technique at room temperature. XRD pattern confirmed the crystalline nature of prepared sample. Rietveld analysis used for further structural investigations and confirmed the existence of rhombohedral symmetry (R3c space group). The dielectric response shows dispersion at lower frequency range and becomes frequency independent at high frequency. The approximation of conduction mechanism is determined by the temperature dependent behavior of frequency exponent `s'. Fitting results suggests the applicability of small polaron conduction mechanism at lower temperatures and CBH model at higher temperature. Room temperature magnetic measurements give the evidence of significant enhancement in magnetic properties with remanent magnetization (Mr = 0.1218 emu/g) and coercive field (Hc = 3.5342 kOe).

  10. Decay of mass-separated 3.0min 195gBi to levels in 195Pb and shape coexistence in the neutron-deficient odd-mass Pb isotopes

    International Nuclear Information System (INIS)

    Griffin, J.C.; Braga, R.A.; Fink, R.W.; Bingham, C.R.; Coenen, E.; Huyse, M.; Duppen, P. van

    1991-01-01

    The radioactive decay of mass-separated 3.0 m 195g Bi to 195 Pb has been studied with the UNISOR and LISOL facilities. Time-sequenced spectra of γ-rays, X-rays, and conversion electrons have been obtained, together with γγt, γXt, eγt, and eXt coincidence data. From this information, a decay scheme has been constructed consisting of 23 excited states and 34 transitions in 195 Pb. Transitions with E0 multipole admixtures, indicative of shape coexistence, have been found to de-excite positive-parity levels at 1093, 1329, and 1380 keV. The beta-decay energy of the 195 Bi ground state is deduced to be Q EC =4800 +600 -550 keV based on the measurement of γ-ray-gated K/β + ratios. The excitation energy of the i 13/2 isomer in 195 Pb has been determined to be 203±4 keV from the α-decays of 199m,g Po. (orig.)

  11. Thick films of Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O by solution processes

    International Nuclear Information System (INIS)

    Barboux, P.; Tarascon, J.M.; Shokoohi, F.; Wilkens, B.J.; Schwartz, C.L.

    1988-01-01

    We have prepared superconducting thick films of the Bi-based and the Tl-based cuprates via the decomposition of aqueous-glycerol solutions containing the salts of the elements. Preliminary results are presented in this work. The substrates are coated prior to heat treating, either by dipping or by spraying on various substrates heated at 200 0 C. Short firing times are required in order to minimize the loss of the constituent Bi (Tl). We find that nitrates of the constituents dissolved in a water-glycerol solution increase the reaction rate in comparison to pure nitrate aqueous solutions. They also help to produce the correct superconducting phase before some reaction with the substrate occurs or too much of the constituent Bi (Tl) is lost during heating to form the superconducting phase. However, the thallium phases cannot be obtained if the films are not fired in the presence of a high pressure of thallium in a sealed capsule. The films are composed of platelets, a few microns large, that are on average oriented parallel to the substrate with their c axis normal. The Bi films show an onset temperature at 85 K and zero resistance at 75 K while the Tl films show an onset temperature of 105 K and zero resistance at 95 K. The critical currents obtained to date are quite low (∼50 A/cm 2 at 77 K for the thallium phase)

  12. Effect of cationic size in Hg (Tl/Bi) Ba2Ca2Cu3O8+δ on ...

    Indian Academy of Sciences (India)

    In this paper we have reported investigations on the effect of simultaneous substitution of Bi and Tl at the H site in the oxygen deficient HO layer of HBa2Ca2Cu3O8+ cuprate superconductor. Bulk polycrystalline samples have been prepared by the two-step solid state reaction process (precursor route). It has been ...

  13. Structure and some magnetic properties of (BiFeO3x-(BaTiO31−x solid solutions prepared by solid-state sintering

    Directory of Open Access Journals (Sweden)

    Kowal Karol

    2015-03-01

    Full Text Available This paper presents the results of the study on structure and magnetic properties of the perovskite-type (BiFeO3x-(BaTiO31−x solid solutions. The samples differing in the chemical composition (x = 0.9, 0.8, and 0.7 were produced according to the conventional solid-state sintering method from the mixture of powders. Moreover, three different variants of the fabrication process differing in the temperatures and soaking time were applied. The results of X-ray diffraction (XRD, Mössbauer spectroscopy (MS, and vibrating sample magnetometry (VSM were collected and compared for the set of the investigated materials. The structural transformation from rhombohedral to cubic symmetry was observed for the samples with x = 0.7. With increasing of BaTiO3 concentration Mössbauer spectra become broadened reflecting various configurations of atoms around 57Fe probes. Moreover, gradual decreasing of the average hyperfine magnetic field and macroscopic magnetization were observed with x decreasing.

  14. Novel optically active lead-free relaxor ferroelectric (Ba0.6Bi0.2Li0.2)TiO3

    International Nuclear Information System (INIS)

    Borkar, Hitesh; Rao, Vaibhav; Barvat, Arun; Pal, Prabir; Kumar, Ashok; Dutta, Soma; Tomar, M; Gupta, Vinay; Scott, J F

    2016-01-01

    We discovered a near-room-temperature lead-free relaxor-ferroelectric (Ba 0.6 Bi 0.2 Li 0.2 )TiO 3 (BBLT) having A-site compositionally disordered ABO 3 perovskite structure. Microstructure-property relations revealed that the chemical inhomogeneities and development of local polar nano-regions (PNRs) are responsible for dielectric dispersion as a function of probe frequencies and temperatures. Rietveld analysis indicates mixed crystal structure with 80% tetragonal structure (space group P4mm) and 20% orthorhombic structure (space group Amm2), which is confirmed by the high resolution transmission electron diffraction (HRTEM). Dielectric constant and tangent loss dispersion with and without illumination of light obey nonlinear Vogel–Fulcher (VF) relations. The material shows slim polarization–hysteresis (P – E) loops and excellent displacement coefficients (d 33 ∼ 233 pm V −1 ) near room temperature, which gradually diminish near the maximum dielectric dispersion temperature (T m ) . The underlying physics for light-sensitive dielectric dispersion was probed by x-ray photon spectroscopy (XPS), which strongly suggests that mixed valence of bismuth ions, especially Bi 5+ ions, comprise most of the optically active centers. Ultraviolet photoemission measurements showed most of the Ti ions are in 4 +  states and sit at the centers of the TiO 6 octahedra; along with asymmetric hybridization between O 2 p and Bi 6 s orbitals, this appears to be the main driving force for net polarization. This BBLT material may open a new path for environmental friendly lead-free relaxor-ferroelectric research. (paper)

  15. The crystal structure of (001) twinned xilingolite, Pb3Bi2S6, from Mittal-Hohtenn, Valais, Switzerland

    DEFF Research Database (Denmark)

    Berlepsch, Peter; Armbruster, Thomas; Makovicky, Emil

    2002-01-01

    geology, xilingolite, crystal structure, twinning, lillianite homologue, electron-microprobe analyses, cannizzarite, Bi-containing galena, Mittal-Hohtenn, Valais, Switzerland......geology, xilingolite, crystal structure, twinning, lillianite homologue, electron-microprobe analyses, cannizzarite, Bi-containing galena, Mittal-Hohtenn, Valais, Switzerland...

  16. Analysis of the neutron energy spectra from the sup(208)Pb (p,n) sup(208)Bi reaction at Esub(p)=200 MeV

    International Nuclear Information System (INIS)

    Ershov, S.N.; Fayans, S.A.; Gareev, F.A.; Pyatov, N.I.

    1986-01-01

    Microscopic calculation of the small-angle neutron energy spectra from the 208 Pb (p, n) 208 Bi reaction at Esub(p)=200 MeV are presented. It is shown that the distorted-wave impulse approximation and the microscopic theory of finite Fermi systems can be employed for describing the low-energy excitation region 0 <= Q <= 30 MeV with small momentum transfers. A quantitative estimate is obtained for the local charge of quasiparticles esub(q)[σtau]=0.8 that characterizes the quenching of the integral strength of spin-flip low-energy transitions and the relevant effects are discussed

  17. Corrosion behavior of austenitic and ferritic/martensitic steels in oxygen-saturated liquid Pb-Bi eutectic at 450circC and 550circC

    OpenAIRE

    倉田 有司; 二川 正敏; 斎藤 滋

    2005-01-01

    Static corrosion tests of various austenitic and ferritic/martensitic steels were conducted in oxygen-saturated liquid Pb-Bi at 450circC and 550circC for 3000h to study the effects of temperature and alloying elements on corrosion behavior. Oxidation, grain boundary corrosion, dissolution and penetration were observed. The corrosion depth decreases at 450circC with increasing Cr content in steels regardless of ferritic/martensitic or austenitic steels. Appreciable dissolution of Ni and Cr doe...

  18. First principles study of (Cd, Hg, In, Tl, Sn, Pb, As, Sb, Bi, Se) modified Pt(111), Pt(100) and Pt(211) electrodes as CO oxidation catalysts

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir

    2015-01-01

    . The coverage dependence as a function of potential for ten different adatom species (Cd, Hg, In, Tl, Sn, Pb, As, Sb, Bi, Se) on bare and CO saturated Pt(111), Pt(100) and Pt(211) surfaces has been established by means of Density Functional Theory calculations. Most of the adatoms are very stable under standard......, given by the OH formation potentials from water, is dependent on the oxophilicity of the adatoms, and is found to scale almost inversely with the adatom stability. In electrolyte solutions saturated with CO, the stability reduces to roughly half of that on bare Pt surfaces. Irrespective of the CO...

  19. The charge-distribution differences of 209Bi, 208207206204Pb and 205203Tl investigated by elastic electron scattering and muonic X-ray data

    International Nuclear Information System (INIS)

    Euteneuer, H.; Friedrich, J.; Voegler, N.

    1978-01-01

    Elastic electron scattering cross sections and cross-section ratios have been measured for the stable Bi, Pb and Ti isotopes. The data are analysed with the Fourier-Bessel method and the charge-distribution differences of the isotonic and isotopic pairs are presented as well as the Fourier-Bessel coefficients of the seven single nuclei. To improve the accuracy of the results, muonic X-ray data are incorporated into the analysis. The measured Δrho(r) are compared with the simple shell model, where the stretching due to the additional nucleons is taken into account, and with more sophisticated HF calculations. (Auth.)

  20. Consistent dispersive optical-model analyses for n+209Bi and n+208Pb from -20 to +80 MeV

    International Nuclear Information System (INIS)

    Weisel, G.J.; Tornow, W.; Howell, C.R.

    1993-01-01

    Complementary databases were constructed from published and some new measurements of σ(θ), Ay(θ) and σ T for n+ 208 Pb and n+ 209 Bi covering the energy range 1.0 to 80 MeV. A dispersive optical-model analysis was performed for both scattering systems while constraining many of the parameters to be identical. A good representation of the data is obtained with conventional geometry and spin-orbit parameters. The 208 Pb model predicts quite well measured energies of single-particle and single-hole bound states. Occupation probabilities are calculated. A fully constrained model is presented in which the only differences between the two systems are the Fermi energy and the usual isospin term. This latter model represents all the data well

  1. Study and characterization of the BBT (BaBi{sub 4}Ti{sub 4}O{sub 15}) ceramic added with 1 wt. % Nb{sub 2}O{sub 5}; Estudo e caracterizacao da ceramica BBT (BaBi{sub 4}Ti{sub 4}O{sub 15}) dopada com 1% de Nb{sub 2}O{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Silva, P.M.O.; Sales, A.J.M.; Freitas, D.B.; Oliveira, R.G.M.; Sombra, A.S.B., E-mail: paulo2003@gmail.com [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil); Sales, J.C. [Universidade Estadual Vale do Acarau (UVA), Fortaleza, CE (Brazil)

    2012-07-01

    This study aims to synthesize and characterize the ceramic BBT (BaBi{sub 4}TI{sub 4}O{sub 15}) doped with 1% by mass of the densification Nb2O5 to improve the products. The phase of the BBT has been found by solid state reaction. The mixed oxides starting processed by high-energy milling in planetary mill reactor polymer and spheres of zirconia and calcined at 850°C/3h. Later, 'bulks' prepared with the calcined powder were sintered at 950°C/3h. The calcined powder was characterized by X-ray diffraction data and refined by the beta 3.2 DBWSTools program using the Rietveld method. The grain morphology and distribution of pores on the surface of the 'bulks' were analyzed by Scanning Electron Microscopy. The result confirmed the refined to obtain the single phase with tetragonal structure BaBi{sub 4}TI{sub 4}O{sub 15} density of 5.088 g/cm3 calculated in the unit cell. SEM analysis by SEM showed improved densification of the doped. (author)

  2. Study of the variation of the E-I curves in the superconducting to normal transition of Bi-2212 textured ceramics by Pb addition

    Directory of Open Access Journals (Sweden)

    Sotelo, A.

    2006-06-01

    Full Text Available Vitreous cylinders with compositions Bi2-xPbxSr2CaCu2Oy, (x = 0, 0.2, 0.4 and 0.6 were prepared and used as precursors to fabricate textured bars through a laser floating zone melting method (LFZ. The resulting textured cylindrical bars were annealed, followed by their electrical characterization. The microstructure was determined and correlated with the electrical measured properties. The influence of Pb doping on the sharpness of the superconducting to normal transition on the E-I curves has been determined. The sharpest transitions have been obtained for samples doped with 0.4Pb.

    Se han preparado precursores de tipo vítreo en forma de cilindro con composiciones nominales Bi2-xPbxSr2CaCu2Oy, con x = 0, 0.2, 0.4 y 0.6. Estos cilindros se han utilizado como precursores para fabricar barras texturadas por medio de una técnica de fusión zonal inducida por láser (LFZ. Estas barras texturadas se recocieron a diferentes temperaturas y se caracterizaron eléctricamente. Además, se examinó su microestructura para correlacionarla con las propiedades eléctricas medidas. La variación de la transición del estado superconductor al normal se ha relacionado con el dopaje con Pb a través de las curvas E-I. Las mejores transiciones se han obtenido para muestras dopadas con 0.4 Pb.

  3. Nanocomposite dielectrics in PbO-BaO-Na2O-Nb2O5-SiO2 system with high breakdown strength for high voltage capacitor applications.

    Science.gov (United States)

    Zhang, Qingmeng; Luo, Jun; Tang, Qun; Han, Dongfang; Zhou, Yi; Du, Jun

    2012-11-01

    Nanocomposite dielectrics in 6PbO-4BaO-20Na2O-40Nb2O5-30SiO2 system were prepared via melt-quenching followed by controlled crystallization. X-ray diffraction studies reveal that Pb2Nb2O7, Ba,NaNb5O15, NaNbO3 and PbNb2O6 phases are formed from the as-quenched glass annealed in temperature range from 700 degrees C to 850 degrees C. Ba2NaNb5O15, Pb2Nb2O7 crystallizes at 700 degrees C and then Pb2Nb2O7 disappears at 850 degrees C, while PbNb2O6 and NaNbO3 are formed at 850 degrees C. Microstructural observation shows that the crystallized particles are nanometer-sized and randomly distributed with glass matrix being often found at grain boundaries. The dielectric constant of the nanocomposites formed at different crystallization temperatures shows good frequency and electric field stability. The breakdown strength is slightly decreased when the glass-ceramics thickness is varied from 1 mm to 4 mm. The corresponding energy density could reach 2.96 J/cm3 with a breakdown strength of 58 kV/mm for thickness of 1 mm.

  4. Comparison of reactions for the production of 258,257Db: 208Pb(51V,xn) and 209Bi(50Ti,xn)

    Energy Technology Data Exchange (ETDEWEB)

    Gates, Jacklyn M.; Nelson, Sarah L.; Gregorich, Kenneth E.; Dragojevic, Irena; Dullmann, Christoph E.; Ellison, Paul A.; Folden III, Charles M.; Garcia, Mitch A.; Stavsetra, Liv; Sudowe, Ralf; Hoffman, Darleane C.; Nitsche, Heino

    2008-09-29

    Excitation functions for the 1n and 2n exit channels of the 208Pb(51V,xn)259-xDb reaction were measured. A maximum cross section of the 1n exit channel of 2070+1100/-760 pb was measured at an excitation energy of 16.0 +- 1.8 MeV. For the 2n exit channel, a maximum cross section of 1660+450/-370 pb was measured at 22.0 +- 1.8 MeV excitation energy. The 1n excitation function for the 209Bi(50Ti,n)258Db reaction was remeasured, resulting in a cross section of 5480+1750/-1370 pb at an excitation energy of 16.0 +- 1.6 MeV, in agreement with previous values [F. P. Hebberger, et al., Eur. Phys. J. A 12, 57 (2001)]. Differences in cross section maxima are discussed in terms of the fusion probability below the barrier.

  5. Depth profile of production yields of {sup nat}Pb(p, xn) {sup 206,205,204,203,202,201}Bi nuclear reactions

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari Oranj, Leila [Division of Advanced Nuclear Engineering, POSTECH, Pohang 37673 (Korea, Republic of); Jung, Nam-Suk; Kim, Dong-Hyun; Lee, Arim; Bae, Oryun [Pohang Accelerator Laboratory, POSTECH, Pohang 37673 (Korea, Republic of); Lee, Hee-Seock, E-mail: lee@postech.ac.kr [Pohang Accelerator Laboratory, POSTECH, Pohang 37673 (Korea, Republic of)

    2016-11-01

    Experimental and simulation studies on the depth profiles of production yields of {sup nat}Pb(p, xn) {sup 206,205,204,203,202,201}Bi nuclear reactions were carried out. Irradiation experiments were performed at the high-intensity proton linac facility (KOMAC) in Korea. The targets, irradiated by 100-MeV protons, were arranged in a stack consisting of natural Pb, Al, Au foils and Pb plates. The proton beam intensity was determined by activation analysis method using {sup 27}Al(p, 3p1n){sup 24}Na, {sup 197}Au(p, p1n){sup 196}Au, and {sup 197}Au(p, p3n){sup 194}Au monitor reactions and also by Gafchromic film dosimetry method. The yields of produced radio-nuclei in the {sup nat}Pb activation foils and monitor foils were measured by HPGe spectroscopy system. Monte Carlo simulations were performed by FLUKA, PHITS/DCHAIN-SP, and MCNPX/FISPACT codes and the calculated data were compared with the experimental results. A satisfactory agreement was observed between the present experimental data and the simulations.

  6. Improvement of the phase diagram for the pseudobinary PbNb2O6-BaNb2O6 system

    International Nuclear Information System (INIS)

    Venet, M.; Zabotto, F. L.; Eiras, J. A.; Garcia, D.

    2009-01-01

    Characteristics of phase transitions of lead barium niobate compositions around the morphotropic phase boundary were investigated. Using structural characterizations, it was found that the morphotropic phase boundary extends toward a wide composition range, in which both tetragonal (4mm) and orthorhombic (m2m) tungsten bronze phases coexist. In addition, on heating, two phase transitions were observed for all the studied compositions. First, the fraction with m2m symmetry phase transforms into the 4mm symmetry one and, second, the 4mm symmetry phase, which represents the whole material, transforms into the paraelectric phase (4/mmm symmetry). The phase transition temperatures were determined from dielectric characterizations. These results helped to improve the phase diagram of the pseudobinary PbNb 2 O 6 -BaNb 2 O 6 system around the morphotropic phase boundary region.

  7. Synthesis and characterization of Ba_0_._5Pb_0_._5TiO_3 perovskite - type thin films deposited by spin coating at low temperatures

    International Nuclear Information System (INIS)

    Wermuth, T.B.; Wiederkehr, N.A.; Alves, A.K.; Bergmann, C.P.

    2014-01-01

    In this paper we present a non-aqueous sol-gel route for the obtention of solid compounds and thin films of oxide type- perovskite ABO_3, such as Ba_0_._5 Pb_0_._5 TiO_3, synthesized by sol - gel route with subsequent heat treatment. The solid compounds were characterized by X-ray diffraction (XRD) techniques and thermal analysis (TGA / DTA). The thin film was obtained by using spin-coating techniques at low temperatures onto commercial substrates of polymethylmethacrylate (PMMA) and characterized by contact angle, atomic force microscopy (AFM) and scanning electron microscopy (SEM). The results show that the films present microstructures and roughness directly related to annealing temperatures, characterized by the formation of crystalline nanostructures with surface regularity and transparency. (author)

  8. Identifying open-volume defects in doped and undoped perovskite-type LaCoO3, PbTiO3, and BaTiO3

    International Nuclear Information System (INIS)

    Ghosh, Vinita J.; Nielsen, Bent; Friessnegg, Thomas

    2000-01-01

    Dopants, vacancies, and impurity-vacancy clusters have a substantial impact on the properties of perovskite-type metal oxides (general formula ABO 3 ). In order to determine synthesis and processing conditions that optimize the desirable properties of these materials a careful study of these defects is required. It is essential to identify the defects and to map the defect densities. Positron annihilation spectroscopy has often been used to identify vacancy-type defects. Calculations of the positron lifetime and Doppler-broadened profiles of the positron-electron annihilation radiation in undoped and doped LaCoO 3 , PbTiO 3 , and BaTiO 3 are reported, and compared with available experimental data. The results show that these positron techniques are excellent for studying open-volume defects, vacancy-impurity complexes, and for identifying the sublattice occupied by the dopants. (c) 2000 The American Physical Society

  9. Preparation of Bi-Pb-Sr-Ca-Cu-O high Tc thick films on Ag or MgO substrate with superconductor paste; Bi kei ko Tc chodendo paste ni yoru Ag, MgO kibanjo eno atsumaku sakusei

    Energy Technology Data Exchange (ETDEWEB)

    Takabatake, N. [Ishikawa Technical High School, Ishikawa (Japan); Tsubota, T.; Ishikawa, T.; Ohashi, K. [Kanazawa Institute of Technology, Ishikawa (Japan)

    1995-07-15

    The following were reported on making Bi series superconducting thick films by a wet method. A paste was made by adding PSO (or ethanol solution of ethylenegrycol) of Yushiro Chemical Industry Co., Ltd. as a binder to a Bi series 2223 single-phase powder sample (blending composition Bi:Pb:Sr:Ca:Cu=1.8:0.4:2:2:3.2); the sample was then coated on an Ag (or MgO) substrate with a brush; after being dried at 105{degree}C for one hour, it was thermally decomposed at 700{degree}C for one hour; then, the process of prissurized forming (at pressure 2 to 5 ton f/cm{sup 2}) and of sintering at 845{degree}C for 20 hours or more were performed on the sample to form a thick film sample. A critical temperature Tc, critical current density Jc, etc., were measured on such thick film sample. As a result, nearly same values were obtained as Tc (93K) and Jc (84A/cm{sup 2}) which were those of a bulk sample made by using the same powder sample, pressurizing at 2 ton f/cm{sup 2} for pelletizing, and sintering at 845{degree}C for 20 hours. 6 refs., 7 figs., 1 tab.

  10. Electrical transport in low-lead (1-x)BaTiO3–xPbMg1/3Nb2/3O3 ceramics

    Institute of Scientific and Technical Information of China (English)

    J. SUCHANICZ; K. KONIECZNY; K. ŚWIERCZEK; M. LIPIŃSKI; M. KARPIERZ; D. SITKO; H. CZTERNASTEK; K. KLUCZEWSKA

    2017-01-01

    Low-lead (1-x)BaTiO3–xPbMg1/3Nb2/3O3 ceramics (x = 0, 0.025, 0.05, 0.075, 0.1, and 0.15) were prepared by the conventional oxide mixed sintering process, and their optical band gap, Seebeck coefficient, ac ( σac ) and dc ( σdc ) conductivities as a function of temperature were investigated for the first time. It was found that all samples have p-type conductivity. The low-frequency (20 Hz–2 MHz) ac conductivity obeys a power law σac ~ ωs , which is characteristic for disordered materials. The frequency exponent s is a decreasing function of temperature and tends to zero at high temperature. σac is proportional to ω0.07 – ω0.31 in the low-frequency region and to ω0.51 – ω0.98 in the high-temperature region. The temperature dependence of the dc conductivity showed a change in slope around the temperature at which the phase transition appeared. Both ac and dc conductivities showed a thermally activated character and possessed linear parts with different activation energies and some irregular changes. It was found that the hopping charge carriers dominate at low temperature and small polarons and oxygen vacancies dominate at higher temperature. (1-x)BaTiO3–xPbMg1/3Nb2/3O3 ceramics are expected to be promising new candidate for low-lead electronic materials.

  11. Simultaneous determination of V, As, Se, Cd, Ba and Pb in coal by ICP-MS after high pressure oxygen combustion

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, K.; Arikawa, Y. [Japan Womens University, Tokyo (Japan). Graduate School of Science

    2007-04-15

    A simple decomposition procedure by a high pressure oxygen combustion method was employed for the determination of six elements (V, As, Se, Cd, Ba and Pb) in coal by inductively coupled plasma mass spectrometry (ICP-MS). Combustion under 3 MPa pressure of oxygen in a sealed bomb is a simple and effective method for the decomposition of carbonaceous materials. Organic components are burnt to form CO{sub 2} and H{sub 2}O. Other components also form oxides, which are absorbed in the absorbing solution of a 5 mL of 5% HNO{sub 3} - 1% H{sub 2}O1 Mixed solution put in a bomb. To completely decompose the sample, 600 mg of starch is added to 300 mg of a ground coal sample. Though ignition normally takes about s, 30 min is required before opening the bomb to keep to the oxides absorbed into the absorbing solution. The accuracy of the procedure was evaluated by comparing the determination value of each element with a certified value of a standard reference material. In this study, NIST SRM 1632c and 1632b, given by the National Institute for Standards and Technology in Washington DC, USA were used as standard reference materials. The results obtained by ICP-MS after high pressure oxygen combustion showed good agreements with the certified values of NIST 1632c for 6 elements (V, As, Se, Cd, Ba, Pb). This method was applied to the determination of 6 elements in coal real samples supplied by CCUJ (Center of Coal Utilization Japan).

  12. Comparison of the corrosion behavior of austenitic and ferritic/martensitic steels exposed to static liquid Pb Bi at 450 and 550 °C

    Science.gov (United States)

    Kurata, Y.; Futakawa, M.; Saito, S.

    2005-08-01

    Static corrosion tests of various steels were conducted in oxygen-saturated liquid Pb-Bi eutectic at 450 °C and 550 °C for 3000 h to study the effects of temperature and alloying elements on corrosion behavior in liquid Pb-Bi. Corrosion depth decreases at 450 °C with increasing Cr content in steels regardless of ferritic/martensitic steels or austenitic steels. Appreciable dissolution of Ni and Cr does not occur in the three austenitic steels at 450 °C. Corrosion depth of ferritic/martensitic steels also decreases at 550 °C with increasing Cr content in steels whereas corrosion depth of austenitic steels, JPCA and 316SS becomes larger due to ferritization caused by dissolution of Ni at 550 °C than that of ferritic/martensitic steels. An austenitic stainless steel containing about 5%Si exhibits fine corrosion resistance at 550 °C because the protective Si oxide film is formed and prevents dissolution of Ni and Cr.

  13. Comparison of the corrosion behavior of austenitic and ferritic/martensitic steels exposed to static liquid Pb-Bi at 450 and 550 deg. C

    International Nuclear Information System (INIS)

    Kurata, Y.; Futakawa, M.; Saito, S.

    2005-01-01

    Static corrosion tests of various steels were conducted in oxygen-saturated liquid Pb-Bi eutectic at 450 deg. C and 550 deg. C for 3000 h to study the effects of temperature and alloying elements on corrosion behavior in liquid Pb-Bi. Corrosion depth decreases at 450 deg. C with increasing Cr content in steels regardless of ferritic/martensitic steels or austenitic steels. Appreciable dissolution of Ni and Cr does not occur in the three austenitic steels at 450 deg. C. Corrosion depth of ferritic/martensitic steels also decreases at 550 deg. C with increasing Cr content in steels whereas corrosion depth of austenitic steels, JPCA and 316SS becomes larger due to ferritization caused by dissolution of Ni at 550 deg. C than that of ferritic/martensitic steels. An austenitic stainless steel containing about 5%Si exhibits fine corrosion resistance at 550 deg. C because the protective Si oxide film is formed and prevents dissolution of Ni and Cr

  14. Structural, Dielectric, and Electrical Properties of Bi1- x Pb x Fe1- x (Zr0.5Ti0.5) x O3

    Science.gov (United States)

    Panda, Niranjan; Pattanayak, Samita; Choudhary, R. N. P.

    2015-12-01

    Polycrystalline samples of Bi1- x Pb x Fe1- x (Zr0.5Ti0.5) x O3 (BPFZTO) with x = 0.0, 0.2, 0.3, and 0.4 were prepared by high-temperature solid-state reaction. Preliminary structural analysis of calcined powders of the materials by use of x-ray powder diffraction confirmed formation of single-phase systems with the tetragonal structure. Room-temperature scanning electron micrographs of the samples revealed uniform distribution of grains of low porosity and different dimensions on the surface of the samples. The frequency-temperature dependence of dielectric and electric properties was studied by use of dielectric and complex impedance spectroscopy over a wide range of frequency (1 kHz to 1 MHz) at different temperatures (25-500°C). The dielectric constant of BiFeO3 (BFO) was enhanced by substitution with Pb(Zr0.5Ti0.5)O3 (PZT) whereas the dielectric loss of the BPFZTO compounds decreased with increasing PZT content. A significant contribution of both grains and grain boundaries to the electrical response of the materials was observed. The frequency-dependence of the ac conductivity of BPFZTO followed Jonscher's power law. Negative temperature coefficient of resistance behavior was observed for all the BPFZTO samples. Conductivity by thermally excited charge carriers and oxygen vacancies in the materials was believed to be of the Arrhenius-type.

  15. Production of BiPbSrCaCuO thin films on MgO and Ag/MgO substrates by electron beam deposition techniques

    CERN Document Server

    Varilci, A; Gorur, O; Celebi, S; Karaca, I

    2002-01-01

    Superconducting BiPbSrCaCuO thin films were prepared on MgO(001) and Ag/MgO substrates using an electron beam (e-beam) evaporation technique. The effects of annealing temperature and Ag diffusion on the crystalline structure and some superconducting properties, respectively, were investigated by X-ray diffraction, atomic force microscopy, and by measurements of the critical temperature and the critical current density. It was shown that an annealing of both types of films at 845 or 860 C resulted in the formation of mixed Bi-2223 and Bi-2212 phases with a high degree of preferential orientation with the c-axis perpendicular to the substrates. The slight increase of the critical temperature from 103 K to 105 K, the enhancement of the critical current density from 2 x 10 sup 3 to 6 x 10 sup 4 A/cm sup 2 , and the improved surface smoothness are due to a possible silver doping from the substrate. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  16. Synthesis, structural and semiconducting properties of Ba(Cu1/3 Sb2/3)O3-PbTiO3 solid solutions

    Science.gov (United States)

    Singh, Chandra Bhal; Kumar, Dinesh; Prashant, Verma, Narendra Kumar; Singh, Akhilesh Kumar

    2018-05-01

    We report the synthesis and properties of a new solid solution 0.05Ba(Cu1/3Sb2/3)O3-0.95PbTiO3 (BCS-PT) which shows the semiconducting properties. In this study, we have designed new perovskite-type (ABO3) solid solution of BCS-PT that have tunable optical band gap. BCS-PT compounds were prepared by conventional solid-state reaction method and their structural, micro-structural and optical properties were analyzed. The calcination temperature for BCS-PT solid solutions has been optimized to obtain a phase pure system. The Reitveld analysis of X-ray data show that all samples crystallize in tetragonal crystal structure with space group P4mm. X-ray investigation revealed that increase in calcination temperature led to increase of lattice parameter `a' while `c' parameter value lowered. The band gap of PbTiO3 is reduced from 3.2 eV to 2.8 eV with BCS doping and with increasing calcination temperature it further reduces to 2.56 eV. The reduced band gap indicated that the compounds are semiconducting and can be used for photovoltaic device applications.

  17. Density functional theory computational study of ferroelectricity and piezoelectricity in BaTiO3/PbTiO3 (0 1 1) superlattices

    Science.gov (United States)

    Lou, Yaoding; Deng, Junkai; Zhe Liu, Jefferson

    2018-04-01

    The structure, ferroelectricity (FE), and piezoelectricity of epitaxial BaTiO3/PbTiO3 (BTO/PTO) (0 1 1) superlattices are studied using density functional theory calculations. Our results show that compressive strain arising from the SrTiO3 (0 1 1) substrate stabilizes the (BTO) m /(PTO) n (0 1 1) superlattices in orthorhombic phase with the FE polarization along [0 1 1] direction. Tuning the BTO contents significantly changes the structural, ferroelectric and piezoelectric properties. The FE polarization of superlattices significantly drops with increasing BTO contents, which can be attributed to depolarization of the PTO layers. The averaged c/a ratio of the whole superlattices exhibits anomalous non-monotonic relation with respect to BTO contents. Interestingly, our results predict the (0 1 1) superlattices can enhance the piezoelectric coefficient e 33 with a maximum value at ~67% BTO concentration. This result suggests a potential avenue to design high performance piezoelectric materials with less Pb contents. In-depth analysis reveals the B-site Ti cation as the origin for the enhanced e 33 value, which implies the potential of B-site cation engineering in perovskite heterostructure designs.

  18. Structural and Moessbauer Effect Studies of 0.7Bi0.95Dy0.05FeO3-0.3Pb(Fe0.5Nb0.5)O3 Multiferroic

    International Nuclear Information System (INIS)

    Stoch, A.; Kulawik, J.; Stoch, P.; Maurin, J.; Zachariasz, P.

    2011-01-01

    0.7Bi 0.95 Dy 0.05 FeO 3 -0.3Pb(Fe 0.5 Nb 0.5 )O 3 is a multiferroic material which exhibits ferroelectric and antiferromagnetic ordering. In this paper the way of the synthesis of 0.7Bi 0.95 Dy 0.05 FeO 3 -0.3Pb(Fe 0.5 Nb 0.5 )O 3 is presented. The detailed X-ray and Moessbauer effect studies were done and crystal and hyperfine interaction parameters were obtained. (authors)

  19. Competition from the ν/sub e/ 208Pb → 208Bi e- reaction in a search for ν/sub μ/-bar → ν/sub e/-bar oscillation

    International Nuclear Information System (INIS)

    Toevs, J.W.; Kruse, H.W.

    1981-01-01

    Inverse beta-decay reactions produced by electron neutrinos may compete with muon neutrino reactions in experiments utilizing the neutrino flux from a beam stop. The cross section and angular distribution for one such reaction, ν/sub e/ 208 Pb → 208 Bi e - , have been calculated with the aid of the results of an investigation of 208 Pb (p,n) 208 Bi at low momentum transfer. The implications of this reaction on an experiment to study neutrino oscillation are discussed. 2 figures

  20. Effects of A-site nonstoichiometry on oxide ion conduction in 0.94Bi0.5Na0.5TiO3–0.06BaTiO3 ceramics

    Directory of Open Access Journals (Sweden)

    Sasiporn Prasertpalichat

    2016-06-01

    Full Text Available Lead free 0.94(Bi0.5Na0.5TiO3–0.06BaTiO3 ceramics were prepared by conventional solid-state mixed oxide route with the A-site stoichiometry modified to incorporate donor-doping (through Bi-excess and acceptor-doping (through Na-excess. Both stoichiometric and nonstoichiometric ceramics exhibited a single perovskite phase with pseudo-cubic symmetry. A significant improvement in the dielectric properties was observed in Bi-excess compositions and a deterioration in the dielectric properties was observed in Na-excess compositions. Impedance spectroscopy was utilized to analyze the effects of A-site nonstoichiometry on conduction mechanisms. Compositions with Bi-excess resulted in an electrically homogeneous microstructure with an increase in resistivity by ∼3–4 orders of magnitude and an associated activation energy of 1.57eV which was close to half of the optical bandgap. In contrast, an electrically heterogeneous microstructure was observed in both the stoichiometric and Na-excess compositions. In addition, the Na-excess compositions exhibited low resistivities (ρ∼103Ω-cm with characteristic peaks in the impedance data comparable to the recent observations of oxide ion conduction in (Bi0.5Na0.5TiO3. Long term annealing studies were also conducted at 800∘C to identify changes in crystal structure and electrical properties. The results of this study demonstrates that the dielectric and electrical properties of 0.94(Bi0.5Na0.5TiO3–0.06BaTiO3 ceramics are very sensitive to Bi/Na stoichiometry.

  1. Electronic structure of the gold/Bi2Sr2CaCu2O8 and gold/EuBa2Cu3O7-δ interfaces as studied by photoemission spectroscopy

    International Nuclear Information System (INIS)

    Dessau, D.S.; Shen, Z.; Wells, B.O.; Spicer, W.E.; List, R.S.; Arko, A.J.; Bartlett, R.J.; Fisk, Z.; Cheong, S.; Mitzi, D.B.; Kapitulnik, A.; Schirber, J.E.

    1990-01-01

    High-resolution photoemission has been used to probe the electronic structure of the gold/Bi 2 Sr 2 CaCu 2 O 8 and gold/EuBa 2 Cu 3 O 7-δ interface formed by a low-temperature (20 K) gold evaporation on cleaved high quality single crystals. We find that the metallicity of the EuBa 2 Cu 3 O 7-δ substrate in the near surface region (∼5 A) is essentially destroyed by the gold deposition, while the near surface region of Bi 2 Sr 2 CaCu 2 O 8 remains metallic. This has potentially wide ranging consequences for the applicability of the different types of superconductors in real devices

  2. Electrode contacts on ferroelectric Pb(Zr x Ti1−x )O3 and SrBi2Ta2O9 thin films and their influence on fatigue properties

    OpenAIRE

    Lee, J. J.; Thio, C. L.; Desu, Seshu B.

    1995-01-01

    The degradation (fatigue) of dielectric properties of ferroelectric Pb(ZrxTi1-x)O-3 (PZT) and SrBi2Ta2O9 thin films during cycling was investigated. PZT and SrBi2Ta2O9 thin films were fabricated by metalorganic decomposition and pulsed laser deposition, respectively. Samples with electrodes of platinum (Pt) and ruthenium oxide (RuO2) were studied. The interfacial capacitance (if any) at the Pt/PZT, RuO2/PZT, and Pt/SrBi2Ta2O9 interfaces was determined from the thickness dependence of low-fiel...

  3. Effect of Sintering Time and Diameter on Bi-Pb-Sr-Ca-Cu-O Superconducting Wire Formation with TiO2 Dopant by Silver (Ag Tube

    Directory of Open Access Journals (Sweden)

    Cindy Al Kindi

    2018-01-01

    Full Text Available Pengaruh waktu sintering dan diameter terhadap pembentukan kawat superkonduktor Bi-Pb-Sr-Ca-Cu-O dengan dopan TiO2 menggunakan tabung perak (Ag menjadi penting untuk dibahas karena hal ini berpengaruh terhadap adanya suhu kritis yang merupakan syarat penting superkonduktor. Pada penelitian ini ada beberapa tahap yang dilakukan yaitu preparasi bahan, proses permesinan, penarikan kawat dan proses perlakuan panas. Serbuk BPSCCO dengan dopan TiO2 dimasukkan ke dalam tabung perak (Ag dan dikalsinasi pada temperatur 820oC selama 20 jam, lalu proses penarikan (Rolling sampai diameter 6 mm dan 2,6 mm serta sintering dilakukan pada temperatur 850oC selama 9 jam dan 30 jam untuk masing-masing ukuran diameter dengan dua kali proses sintering. Hasil penelitian menunjukkan bahwa kawat superkonduktor memiliki suhu kritis yaitu Tc onset = 99 K dan Tc zero = 70 K. Waktu yang sangat berpengaruh pada pembentukan fasa superkonduktor yaitu sintering selama 9 jam sedangkan untuk ukuran diameter kawat yang memiliki suhu kritis yaitu 6 mm, sedangkan waktu sintering selama 30 jam dapat merubah fasa BPSCCO sehingga tidak terbentuk superkonduktor melainkan konduktor dan semikonduktor. Pada diameter 2,6 mm belum menjadi ukuran yang tepat pada pembentukan kawat superkonduktor.   The influence of sintering time and diameter on the formation of Bi-Pb-Sr-Ca-Cu-O superconducting wire with doped TiO2 by silver (Ag tube becomes important to be discussed because of the presence of critical temperature which is an essential condition in superconductors. In this research there are several steps must be done that is: material preparation, machine process, wire drawing and heat process. BPSCCO powder with dopant TiO2 filled into silver (Ag tube with calcination temperature at 820oC for 20 h, then rolling process to diameter 6 mm and 2,6 mm with sintering temperature at 850oC for 9 h and 30 h for each size of diameter by twice sintering process. The results showed that

  4. The crystal structure of emilite, Cu10.7Pb10.7Bi21.3S48, the second 45 Å derivative of the bismuthinite-aikinite solid-solution series

    DEFF Research Database (Denmark)

    Balic-Zunic, Tonci; Topa, Dan; Makovicky, Emil

    2002-01-01

    geology, emilite, Cu10.7Pb10.7Bi21.3S48, aikinite-bismuthinite derivative, crystal structure, Felbertal, scheelite deposit, Austria......geology, emilite, Cu10.7Pb10.7Bi21.3S48, aikinite-bismuthinite derivative, crystal structure, Felbertal, scheelite deposit, Austria...

  5. The crystal structure of Cu1.6Pb1.6Bi6.4S12, a new 44.8 Å derivative of the bismuthinite-aikinite solid-solution series

    DEFF Research Database (Denmark)

    Topa, Dan; Balic-Zunic, Tonci; Makovicky, Emil

    2000-01-01

    Cu1.6Pb1.6Bi6.4S12, aikinite-bismuthinite derivative, crystal structure, Felbertal, scheelite deposit, Austria......Cu1.6Pb1.6Bi6.4S12, aikinite-bismuthinite derivative, crystal structure, Felbertal, scheelite deposit, Austria...

  6. Evolving morphotropic phase boundary in lead-free (Bi1/2Na1/2)TiO3-BaTiO3 piezoceramics

    Science.gov (United States)

    Jo, Wook; Daniels, John E.; Jones, Jacob L.; Tan, Xiaoli; Thomas, Pamela A.; Damjanovic, Dragan; Rödel, Jürgen

    2011-01-01

    The correlation between structure and electrical properties of lead-free (1-x)(Bi1/2Na1/2)TiO3-xBaTiO3 (BNT-100xBT) polycrystalline piezoceramics was investigated systematically by in situ synchrotron diffraction technique, combined with electrical property characterization. It was found that the morphotropic phase boundary (MPB) between a rhombohedral and a tetragonal phase evolved into a morphotropic phase region with electric field. In the unpoled material, the MPB was positioned at the transition from space group R3m to P4mm (BNT-11BT) with optimized permittivity throughout a broad single-phase R3m composition regime. Upon poling, a range of compositions from BNT-6BT to BNT-11BT became two-phase mixture, and maximum piezoelectric coefficient was observed in BNT-7BT. It was shown that optimized electrical properties are related primarily to the capacity for domain texturing and not to phase coexistence.

  7. Evolving morphotropic phase boundary in lead-free (Bi1/2Na1/2)TiO3-BaTiO3 piezoceramics

    International Nuclear Information System (INIS)

    Jo, Wook; Roedel, Juergen; Daniels, John E.; Jones, Jacob L.; Tan Xiaoli; Thomas, Pamela A.; Damjanovic, Dragan

    2011-01-01

    The correlation between structure and electrical properties of lead-free (1-x)(Bi 1/2 Na 1/2 )TiO 3 -xBaTiO 3 (BNT-100xBT) polycrystalline piezoceramics was investigated systematically by in situ synchrotron diffraction technique, combined with electrical property characterization. It was found that the morphotropic phase boundary (MPB) between a rhombohedral and a tetragonal phase evolved into a morphotropic phase region with electric field. In the unpoled material, the MPB was positioned at the transition from space group R3m to P4mm (BNT-11BT) with optimized permittivity throughout a broad single-phase R3m composition regime. Upon poling, a range of compositions from BNT-6BT to BNT-11BT became two-phase mixture, and maximum piezoelectric coefficient was observed in BNT-7BT. It was shown that optimized electrical properties are related primarily to the capacity for domain texturing and not to phase coexistence.

  8. Dielectric and magnetic characterization of the electroceramic Ba2Co2Fe12O22 doped with Bi2O3 for applications in electronics components

    International Nuclear Information System (INIS)

    Pires Junior, G.F.M.; Sales, A.J.M.; Rodrigues, H.O.; Sombra, A.S.B.

    2012-01-01

    The objective of this work is to study the dielectric and magnetic properties of electroceramics (Ba 2 Co 2 Fe 12 O 22 - Co 2 Y) doped with (3; 5 and 10 wt%) of Bi 2 O 3 in order to promote better dielectric and magnetic properties for applications in electronics. Phase Co 2 Y was obtained through the method of solid-state reaction. The structural characterization was performed by X-ray Diffraction using the Rietveld refinement. Magnetic hysteresis curves of the samples were obtained at room temperature. The Impedance Spectroscopy was used in the study of the dielectric function of frequency in the range 100-100 MHz, at room temperature. It follows that the Rietveld refinement confirmed the structure to the hexagonal crystalline phase obtained. The curve analysis confirmed the magnetic hysteresis behavior of the ferrimagnetic samples. Furthermore, the samples showed large values of dielectric permittivity (30.8) and small dielectric loss (3,66 x10 -1 ) at 100 MHz for the sample B1, making them passive miniaturization. (author)

  9. Stress induced enhanced polarization in multilayer BiFeO{sub 3}/BaTiO{sub 3} structure with improved energy storage properties

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Savita [Department of Physics and Astrophysics, University of Delhi, Delhi (India); Department of Applied Physics, Delhi Technological University, Delhi (India); Tomar, Monika [Physics Department, Miranda House, University of Delhi, Delhi (India); Kumar, Ashok [CSIR-National Physical Laboratory, Dr. K.S .Krishnan Marg, Delhi (India); Puri, Nitin K. [Department of Applied Physics, Delhi Technological University, Delhi (India); Gupta, Vinay, E-mail: vgupta@physics.du.ac.in, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi (India)

    2015-10-15

    Present work reports the fabrication of a multilayer (5-layer) structure of BiFeO{sub 3}(BFO)/BaTiO{sub 3}(BTO) using spin-coating technique. The crystallographic structure, surface morphology and ferroelectric behavior of multilayer structure in metal-ferroelectric-metal capacitor have been studied. Le-Bail refinement of X-ray diffraction data revealed the formation of polycrystalline pure perovskite phase with induced stress. The values of remnant (P{sub r}) and saturation polarization (P{sub s}) for BFO/BTO multilayer structure are found to be 38.14 μC/cm{sup 2} and 71.54 μC/cm{sup 2} respectively, which are much higher than the corresponding values reported for bare BFO thin film. A large value of dielectric constant of 187 has been obtained for multilayer structure with a low leakage current density of 1.09 × 10{sup −7} A/cm{sup 2} at applied bias of 10 V. The BFO/BTO multilayer structure favors the enhanced energy storage capacity as compared to bare BFO thin film with improved values of energy-density and charge-discharge efficiency as 121 mJ/cm{sup 3} and 59% respectively, suggesting futuristic energy storage applications.

  10. Stress induced enhanced polarization in multilayer BiFeO3/BaTiO3 structure with improved energy storage properties

    Directory of Open Access Journals (Sweden)

    Savita Sharma

    2015-10-01

    Full Text Available Present work reports the fabrication of a multilayer (5-layer structure of BiFeO3(BFO/BaTiO3(BTO using spin-coating technique. The crystallographic structure, surface morphology and ferroelectric behavior of multilayer structure in metal-ferroelectric-metal capacitor have been studied. Le-Bail refinement of X-ray diffraction data revealed the formation of polycrystalline pure perovskite phase with induced stress. The values of remnant (Pr and saturation polarization (Ps for BFO/BTO multilayer structure are found to be 38.14 μC/cm2 and 71.54 μC/cm2 respectively, which are much higher than the corresponding values reported for bare BFO thin film. A large value of dielectric constant of 187 has been obtained for multilayer structure with a low leakage current density of 1.09 × 10−7 A/cm2 at applied bias of 10 V. The BFO/BTO multilayer structure favors the enhanced energy storage capacity as compared to bare BFO thin film with improved values of energy-density and charge-discharge efficiency as 121 mJ/cm3 and 59% respectively, suggesting futuristic energy storage applications.

  11. Raman and X-ray diffraction study of (Ba,Sr)TiO3/(Bi,Nd)FeO3 multilayer heterostructures

    International Nuclear Information System (INIS)

    Anokhin, A.S.; Bunina, O.A.; Golovko, Yu I.; Mukhortov, V.M.; Yuzyuk, Yu I.; Simon, P.

    2013-01-01

    We report synthesis, X-ray diffraction (XRD) and Raman scattering characterisation of epitaxial heterostructures containing alternating (Bi 0.98 Nd 0.02 )FeO 3 (BNFO) and (Ba 0.8 Sr 0.2 TiO 3 ) (BST) layers deposited on (100) MgO substrates. A significant shift of the BST soft mode and partial depolarisation in the Raman spectra of multilayer heterostructures caused by epitaxial strains were observed. Satellite peaks typical for superlattices were observed in the XRD patterns of multilayer heterostructures with layer thicknesses below 30 nm. Raman spectra of the BNFO/BST superlattice with a modulation period of 10 nm revealed hardening of the soft mode and a dominating symmetric-stretching mode at 705 cm −1 due to distortion in FeO 6 octahedra enforced by the epitaxial strain in the superlattice. - Highlights: • BNFO and BST multilayers and superlattices on (100) MgO. • Raman spectra of superlattices exhibit features not observed in bulk BFO. • Satellites in XRD patterns when layer thickness below 30 nm

  12. Frequency and temperature dependence behaviour of impedance, modulus and conductivity of BaBi4Ti4O15 Aurivillius ceramic

    Directory of Open Access Journals (Sweden)

    Tanmaya Badapanda

    2014-09-01

    Full Text Available In this work, we report the dielectric, impedance, modulus and conductivity study of BaBi4Ti4O15 ceramic synthesized by solid state reaction. X-ray diffraction (XRD pattern showed orthorhombic structure with space group A21am confirming it to be an m = 4 member of the Aurivillius oxide. The frequency dependence dielectric study shows that the value of dielectric constant is high at lower frequencies and decreases with increase in frequency. Impedance spectroscopy analyses reveal a non-Debye relaxation phenomenon since relaxation frequency moves towards the positive side with increase in temperature. The shift in impedance peaks towards higher frequency side indicates conduction in material and favouring of the long rangemotion of mobile charge carriers. The Nyquist plot from complex impedance spectrum shows only one semicircular arc representing the grain effect in the electrical conduction. The modulus mechanism indicates the non-Debye type of conductivity relaxation in the material, which is supported by impedance data. Relaxation times extracted using imaginary part of complex impedance (Z′′ and modulus (M′′ were also found to follow Arrhenius law. The frequency dependent AC conductivity at different temperatures indicates that the conduction process is thermally activated. The variation of DC conductivity exhibits a negative temperature coefficient of resistance behaviour.

  13. (Bi, Pb).sub.2, Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x superconductor and method of making same utilizing sinter-forging

    Science.gov (United States)

    Chen, Nan; Goretta, Kenneth C.; Lanagan, Michael T.

    1998-01-01

    A (BiPb).sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x (Bi223) superconductor with high J.sub.c, phase purity, density and mechanical strength is formed from Bi2223 powder which is synthesized from a mixture of Bi.sub.2 O.sub.3, PbO, SrCO.sub.3, CaCo.sub.3 and CuO. The mixture is milled, then dried and calcined to synthesize the Bi2223 powder with the desired phase purity. The calcination is performed by heating the dried mixture for 50 hours at 840.degree. C. The partially synthesized powder is then milled for 1-4 hours before calcining further for another 50 hours at 855.degree. C. to complete the synthesis. After calcination, the Bi2223 powder is cold pressed to a predetermined density and sinter forged under controlled temperature and time to form a Bi2223 superconductor with the desired superconducting properties.

  14. (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconductor and method of making same utilizing sinter-forging

    Science.gov (United States)

    Chen, N.; Goretta, K.C.; Lanagan, M.T.

    1998-10-13

    A (BiPb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}(Bi223) superconductor with high J{sub c}, phase purity, density and mechanical strength is formed from Bi2223 powder which is synthesized from a mixture of Bi{sub 2}O{sub 3}, PbO, SrCO{sub 3}, CaCo{sub 3} and CuO. The mixture is milled, then dried and calcined to synthesize the Bi2223 powder with the desired phase purity. The calcination is performed by heating the dried mixture for 50 hours at 840 C. The partially synthesized powder is then milled for 1--4 hours before calcining further for another 50 hours at 855 C to complete the synthesis. After calcination, the Bi2223 powder is cold pressed to a predetermined density and sinter forged under controlled temperature and time to form a Bi2223 superconductor with the desired superconducting properties. 5 figs.

  15. The synthesis of Ba2+ doped multiferroic BiFeO3 nanoparticles by using a hydrothermal approach in the presence of different surface activators and the investigation of structural and magnetic features

    Science.gov (United States)

    Mardani, Reza

    2017-05-01

    In this work, Bi1-x Ba x FeO3 nanoparticles were synthesized by a hydrothermal method in the presence of various surface activators, and different amounts of barium were inserted in a bismuth ferrite (x  =  0.1, 0.15, 0.2) structure instead of bismuth. The structural and magnetic properties, morphology, and size of the synthesized nanoparticles were investigated by XRD, FT-IR, FE-SEM, TEM, DLS and VSM. The XRD analysis results reveal that the synthetic nanoparticles have a single phase. A phase shift from a rhombohedral structure to a tetragonal structure occurs due to the enhanced barium amount in the bismuth ferrite structure. The SEM analysis exhibits a uniform shape of the Bi0.85Ba0.15FeO3 particles and the image observed by TEM clarifies the size of the particles as 11 nm. Furthermore, the effect of the diverse surfaces of activators in the synthesis of Bi0.85Ba0.15FeO3 nanoparticles was studied, revealing that when sugar was used as a surfactant, the particle size reduced and the magnetic properties increased notably.

  16. Structural and electronic investigations of PbTa4O11 and BiTa7O19 constructed from α-U3O8 types of layers

    Science.gov (United States)

    Boltersdorf, Jonathan; Maggard, Paul A.

    2015-09-01

    The PbTa4O11 and BiTa7O19 phases were prepared by ion-exchange and solid-state methods, respectively, and their structures were characterized by neutron time-of-flight diffraction and Rietveld refinement methods (PbTa4O11, R 3 (No. 146), a=6.23700(2) Å, c=36.8613(1) Å; BiTa7O19, P 6 bar c 2 (No. 188), a=6.2197(2) Å, c=20.02981(9) Å). Their structures are comprised of layers of TaO6 octahedra surrounded by three 7-coordinate Pb(II) cations or two 8-coordinate Bi(III) cations. These layers alternate down the c-axis with α-U3O8 types of single and double TaO7 pentagonal bipyramid layers. In contrast to earlier studies, both phases are found to crystallize in noncentrosymmetric structures. Symmetry-lowering structural distortions within PbTa4O11, i.e. R 3 bar c →R3, are found to be a result of the displacement of the Ta atoms within the TaO7 and TaO6 polyhedra, towards the apical and facial oxygen atoms, respectively. In BiTa7O19, relatively lower reaction temperatures leads to an ordering of the Bi/Ta cations within a lower-symmetry structure, i.e., P63/mcm→ P 6 bar c 2 . In the absence of Bi/Ta site disorder, the Ta-O-Ta bond angles decrease and the Ta-O bond distances increase within the TaO7 double layers. Scanning electron microscopy images reveal two particle morphologies for PbTa4O11, hexagonal rods and finer irregularly-shaped particles, while BiTa7O19 forms as aggregates of irregularly-shaped particles. Electronic-structure calculations confirm the highest-energy valence band states are comprised of O 2p-orbitals and the respective Pb 6s-orbital and Bi 6s-orbital contributions. The lowest-energy conduction band states are composed of Ta 5d-orbital contributions that are delocalized over the TaO6 octahedra and layers of TaO7 pentagonal bipyramids. The symmetry-lowering distortions in the PbTa4O11 structure, and the resulting effects on its electronic structure, lead to its relatively higher photocatalytic activity compared to similar structures without

  17. Experimental and theoretical studies of the yields of residual product nuclei produced in thin Pb and Bi targets irradiated by 40 - 2600 MeV protons

    International Nuclear Information System (INIS)

    Titarenko, Yu. E.; Batyaev, V.F.; Karpikhin, E.I.; Zhivun, V.M.; Ignatyuk, A.V.; Lunev, V.P.; Titarenko, N.N.; Shubin, Yu.N.; Barashenkov, V.S.

    2009-10-01

    The Project is aimed at experimental determining and computer-aided theoretical simulating the independent and cumulative yields of residual radioactive product nuclei in high-energy protonirradiated thin targets made of high-isotopic and natural lead ( 206 Pb, 207 Pb, 208 PB, natPb) and bismuth ( 209 Bi) that are the most probable choice to be the target materials in the acceleratordriven (hybrid) systems (ADS) coupled to a high-current proton accelerator. The yields of residual product nuclei are of great importance when estimating such basic radiation-technology characteristics of the hybrid facility targets as the total target activity, the target 'poisoning', the buildup of long-lived nuclides, the α-activity, the content of low-pressure evaporated nuclides (Hg), the content of the chemically-active nuclides that drastically spoil the corrosion resistance of the facility structure materials, etc. In view of the above, the radioactive product nuclide yields from targets materials were experimentally determined using the ITEP U-10 proton accelerator in 55 measurement runs using the monoisotopic and natural lead ( 206 Pb, 207 Pb, 208 PB, natPb) and bismuth ( 209 Bi) targets within the proton energy range fractionated minutely, namely at 0.04, 0.07, 0.10, 0.8, 1.2, 1.4, 1.6, and 2.6 GeV to cover the entire range of the internuclear hadron cascading. As a result, 5972 cumulative and independent yields of residual radioactive product nuclei, whose lifetimes range from 8 minutes to 32 years, have been measured. Besides, the cross sections for the 27 Al(p,x) 24 Na and 27 Al(p,x)7Be monitor reactions have been measured at the same proton energies together with the 27 Al(n,p) 27 Mg reaction rate that characterizes the neutron background contributions in each experiment. The experimental nuclide yields are determined by the direct γ-spectrometry method. The γ-spectrometer resolution is 1.8 keV in the 1332 keV 60 Co γ-line. The experimental γ-spectra are processed by

  18. Comparative study of pinning and creep in Tl2Ba2CaCu2O8 and Bi2Sr2CaCu2O8 single crystals

    International Nuclear Information System (INIS)

    Oussena, M.; Porter, S.; Volkozub, A.V.; de Groot, P.A.J.; Lanchester, P.C.; Ogborne, D.; Weller, M.T.; Balakrishnan, G.; Paul, D.M.

    1993-01-01

    We have compared the pinning and creep in two identically shaped single crystals, Tl 2 Ba 2 CaCu 2 O 8 (Tl 2:2:1:2) and Bi 2 Sr 2 CaCu 2 O 8 (Bi 2:2:1:2) using magnetometry. The critical current density, J c , deduced from the M-H hysteresis loops is found to be the highest in Bi 2:2:1:2 at low temperatures (T c , in this temperature range, is similar for both crystals. At higher temperatures, J c is found to decrease more rapidly with magnetic field in Bi 2:2:1:2 than in Tl 2:2:1:2. The critical current also decreases more quickly with temperature in Bi 2:2:1:2 leading to a vanishing J c at temperatures lower than in the case of Tl 2:2:1:2. I-V characteristic curves have been obtained from measurements of magnetic-sweep-rate dependencies of the hysteresis loops. We have found that the characteristic temperature at which flux motion becomes important is significantly higher in Tl 2:2:1:2 than in Bi 2:2:1:2

  19. Measurement of conversion electrons with the $^{208}Pb(p,n)^{208}Bi$ reaction and derivation of the shell model proton neutron hole interaction from the properties of $^{208}Bi$

    CERN Document Server

    Maier, K H; Dracoulis, G D; Boutachkov, P; Aprahamian, A; Byrne, A P; Davidson, P M; Lane, G L; Marie-Jeanne, Mélanie; Nieminen, P; Watanabe, H

    2007-01-01

    Conversion electrons from 208Bi have been measured using singles and coincidence techniques with the 208Pb(p,n)208Bi reaction at 9 MeV. The new information on multipolarities and spins complements that available from recent gamma-gamma-coincidence studies with the same reaction [Boutachkov et al., Nucl. Phys. A768, 22 (2006)]. The results on electromagnetic decays taken together with information on spectroscopic factors from earlier single-particle transfer reaction measurements represent an extensive data set on the properties of the one-proton one-neutron-hole states below 3 MeV, a spectrum which is virtually complete. Comparison of the experimental observables, namely, energies, spectroscopic factors, and gamma-branching ratios, with those calculated within the shell model allows extraction of the matrix elements of the shell model residual interaction. More than 100 diagonal and nondiagonal elements can be determined in this way, through a least squares fit to the experimental data. This adjustment of the...

  20. Phase stability, oxygen nonstoichiometry, and superconductivity properties of Bi2Sr2CaCu2O8+δ and Bi1.8Pb0.4Sr2Ca2Cu3O10+δ

    International Nuclear Information System (INIS)

    Mozhaev, A.P.; Chernyaev, S.V.; Badun, Y.V.

    1995-01-01

    Phase stability of Bi 2 Sr 2 CaCu 2 O 8+δ (2212) and Bi 1.8 Pb 0.4 Sr 2 Ca 2 Cu 3 O 10+δ (2223) was studied by means of thermogravimetry, dilatometry, high-temperature resistivity, and the powder X-ray methods in the temperature range 700-1000 degrees and at P O2 = 1-10 -4.3 atm. The existence of a high-temperature (peritectic melting) boundary of phase stability was found. The temperatures of low-temperature phase decomposition were determined in air and under an oxygen atmosphere. The change in oxygen content was determined for the 2212 phase in the temperature range 700-860 degrees C and at P O2 = 0.21-10 -3.7 atm by iodometric analysis of quenched samples. It was found that in the single-phase region, the change in oxygen nonstoichiometry had an insignificant influence on T c . It was also shown that the slow cooling of samples led to a significant decrease in T c and transport j c due to partial phase decomposition

  1. Residual tensile stresses and piezoelectric properties in BiFeO3-Bi(Zn1/2Ti1/2O3-PbTiO3 ternary solid solution perovskite ceramics

    Directory of Open Access Journals (Sweden)

    Weilin Zheng

    2016-08-01

    Full Text Available For low dielectric loss perovskite-structured (1-x-yBiFeO3-xBi(Zn1/2Ti1/2O3-yPbTiO3 (BF-BZT-PT (x = 0.04-0.15 and y = 0.15-0.26 ceramics in rhombohedral/tetragonal coexistent phase, structural phase transitions were studied using differential thermal analyzer combined with temperature-dependent dielectric measurement. Two lattice structural phase transitions are disclosed in various BF-BZT-PT perovskites, which is different from its membership of BiFeO3 exhibiting just one lattice structural phase transition at Curie temperature TC= 830oC. Consequently, residual internal tensile stresses were revealed experimentally through XRD measurements on ceramic pellets and counterpart powders, which are reasonably attributed to special structural phase transition sequence of BF-BZT-PT solid solution perovskites. Low piezoresponse was observed and argued extrinsically resulting from residual tensile stresses pinning ferroelectric polarization switching. Post-annealing and subsequent quenching was found effective for eliminating residual internal stresses in those BZT-less ceramics, and good piezoelectric property of d33 ≥ 28 pC/N obtained for 0.70BF-0.08BZT-0.22PT and 0.05 wt% MnO2-doped 0.70BF-0.04BZT-0.26PT ceramics with TC ≥ 640oC, while it seemed no effective for those BZT-rich BF-BZT-PT ceramics with x = 0.14 and 0.15 studied here.

  2. Direct observation of interlayer Josephson vortices in heavily Pb-doped Bi2Sr2CaCu2Oy by scanning superconducting quantum interference device microscopy

    International Nuclear Information System (INIS)

    Kasai, Junpei; Hasegawa, Tetsuya; Okazaki, Noriaki; Koinuma, Hideomi; Nakayama, Yuri; Shimoyama, Jun-ichi; Kishio, Kohji; Motohashi, Teruki; Matsumoto, Yuji

    2006-01-01

    Josephson vortices trapped in cross-sectional edge surfaces of Pb 0.6 Bi 1.4 Sr 2 CaCu 2 O y has been directly observed by using a scanning superconducting quantum interference device (SQUID) microscope. The magnetic field distribution B z around each vortex is substantially anisotropic, compared with the usual vortex in the ab-plane, and is extended over 100 μm toward the in-plane direction. By fitting a theoretical B z function to experimental ones, c-axis penetration depth λ c was estimated to be 11.2 ±0.7 μm, which is in good agreement with the literature value, 12.6 μm, obtained from the Josephson plasma edge frequency. (author)

  3. Critical current density and flux pinning in superconducting wires and coils of silver-clad Bi-Pb-Sr-Ca-Cu-O

    International Nuclear Information System (INIS)

    Dou, S.X.; Liu, H.K.; Apperley, M.H.; Song, K.H.; Sorrell, C.C.; Guo, S.J.; Loberg, B.; Easterling, K.E.

    1991-01-01

    The critical current density (J c ) of Ag-clad of Bi-Pb-Sr-Ca-Cu-O has been measured to be about 12,000 A/cm 2 at 77 K in zero field. This wire was rolled into a tape of thickness 0.1 mm and width of 2 to 3 mm, and a coil of 35 mm diameter was formed. The J c of this coil was measured to be about 2,000 A/cm 2 at 77 K over the full length (1.00 meter) of the coil. In this paper compositions, heat treatment parameters, and cold-deformation for enhancement of J c are presented. The microstructure is characterized and pinning interactions as well as possible weak links are emphasised. (orig.)

  4. Progress report on neutron beam experiments in Thailand: effects of antimony substitutions on the critical temperature of Bi-Pb-Sr-Ca-Cu-O compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sangariyavanich, A; Ampornrat, P [Office of Atomic Energy for Peace, Bangkok (Thailand)

    1998-10-01

    Effects of systematic substitutions of antimony for bismuth in Bi{sub 1.8-x}Pb{sub 0.2}Sb{sub x}Sr{sub 2}Ca{sub 3}Cu{sub 4}O{sub 10} have been investigated. Fabrication of the specimens has been performed by solid state reaction in air. The samples were sintered between 820degC - 843degC for 65 hours and subsequently quenched in liquid nitrogen. The critical temperatures of most specimens as determined by standard four-probe technique was higher than 100 K. Phase identification by X-ray diffraction technique indicated that `2223` and `2234` were the predominant phases in these samples. (author)

  5. Quijarroite, Cu6HgPb2Bi4Se12, a New Selenide from the El Dragόn Mine, Bolivia

    Directory of Open Access Journals (Sweden)

    Hans-Jürgen Förster

    2016-11-01

    Full Text Available Quijarroite, ideally Cu6HgPb2Bi4Se12, is a new selenide species from the El Dragόn mine, Department of Potosí, Bolivia. It most frequently occurs as lath-shaped thin plates (up to 150 µm in length and 20 µm in width intimately (subparallel intergrown with hansblockite, forming an angular network-like intersertal texture. Quijarroite is occasionally also present as sub- to anhedral grains up to 200 µm in length and 50 µm in width. It is non-fluorescent, black and opaque with a metallic luster and black streak. It is brittle, with an irregular fracture and no obvious cleavage and parting. In plane-polarized incident light, quijarroite is weakly pleochroic from cream to very slightly more brownish-cream, displaying no internal reflections. Between crossed polars, quijarroite is moderately anisotropic with pale orange-brown to blue rotation tints. Lamellar twinning on {110} is common; parquet twinning occurs rarely. The reflectance values in the air for the COM (Commission on Ore Mineralogy standard wavelengths (R1 and R2 are: 46.7, 46.8 (470 nm, 47.4, 48.2 (546 nm, 47.1, 48.5 (589 nm, and 46.6, 48.7 (650 nm. Electron-microprobe analyses yielded a mean composition of Cu 13.34, Ag 1.02, Hg 7.67, Pb 16.87, Co 0.03, Ni 0.15, Bi 27.65, Se 33.52, total 100.24 wt %. The mean empirical formula, normalized to 25 apfu (atoms per formula unit, is (Cu5.84Ag0.26Σ = 6.10(Hg1.06Ni0.07Co0.01Σ = 1.14Pb2.27Bi3.68Se11.81 (n = 24. The simplified formula is Cu6HgPb2Bi4Se12. Quijarroite is orthorhombic, space group Pmn21, with a = 9.2413(8, b = 9.0206(7, c = 9.6219(8 Å, V = 802.1(1 Å3, Z = 1. The calculated density is 5.771 g·cm−3. The five strongest X-ray powder-diffraction lines (d in Å (I/I0 (hkl are: 5.36 (55 (111, 3.785 (60 (211, 3.291 (90 (022, 3.125 (100 (212, and 2.312 (50 (400. The crystal structure of quijarroite can be considered a galena derivative and could be derived from that of bournonite. It is a primary mineral, deposited from an

  6. Physiological studies of environmental pollutants. Progress report, September 1, 1975--May 31, 1976. [/sup 210/Po, /sup 203/Pb, /sup 201/Tl, /sup 207/Bi, /sup 65/Zn

    Energy Technology Data Exchange (ETDEWEB)

    Lengemann, F W; Wentworth, R A

    1976-01-01

    In the past year we have looked at the transfer of some members of the actinide decay series into milk of goats. These were /sup 210/Po, /sup 203/Pb, /sup 201/Tl and /sup 207/Bi. All of these appeared in milk after oral ingestion but at levels less than 1 percent per liter. In addition we have looked at the transfer of /sup 65/Zn into milk of goats after oral and I.V. doses; the experiments are incomplete at this time. In controlled temperature studies it was found that 6.6 times as much radioiodine was secreted into milk when goats were at 33/sup 0/ as opposed to 5/sup 0/C. When radioiodine is put into the mammary gland the transfer from milk to body is rapid; more rapid than is the case for /sup 65/Zn. The analysis of these data indicate the need for a model capable of handling expansion of a compartment.

  7. Composite metallic sheathes: the key to low-cost, high strength (Bi,Pb)2Sr2Ca2Cu3O10-based tapes?

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude

    2007-01-01

    (Bi, Pb)(2)Sr2Ca2Cu3O10-based superconducting tapes were prepared by the powder- in- tube process, using a bimetallic sheath consisting of Ag and Ni. Ag was in contact with the superconducting ceramic core and acted as a protective layer against reaction between the external Ni sheath and the cor...

  8. Preparation, characterization and thermoelectric properties of a polyaniline matrix Ge{sub 0.94}Pb{sub 0.01}Bi{sub 0.05}Te composite

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Sude; Zeng, Hao; Zhang, Changxing; Liu, Chun; Xu, Qian [Xihua Univ., Chengdu (China). Center for Advanced Materials and Energy; Zhang, Jianjun [Xihua Univ., Chengdu (China). School of Materials Science and Engineering

    2017-11-01

    In times of industrialization, much low temperature waste heat is released and no viable technology exists which can produce electricity from this low energy density heat. So the long sought-after class thermoelectric (TE) material which directly achieves conversion between thermal and electrical energy obtains much attention. However, the traditional TE materials are alloys of inorganic materials and expensive, and most of them have some level of toxicity, so the research on organic TE materials is very important. The polyaniline (PANI, i. e., a conducting polymer) and PANI matrix Ge{sub 0.94}Pb{sub 0.01}Bi{sub 0.05}Te composite material were prepared. The chemical structure, microstructure and thermoelectric properties were investigated by FTIR, XRD, SEM and ZEM. Results showed that the molecule chains in the PANI were not ranged very neatly, and Ge{sub 0.94}Pb{sub 0.01}Bi{sub 0.05}Te in the composite material formed interconnected network as 20 wt.-% Ge{sub 0.94}Pb{sub 0.01}Bi{sub 0.05}Te was added. Power factor of the composite material increased greatly while its ZT was almost two times of PANI. The addition of Ge{sub 0.94}Pb{sub 0.01}Bi{sub 0.05}Te was an effective method to increase the thermoelectric properties of PANI.

  9. Influence of lanthanum distribution on dielectric and ferroelectric properties of BaBi{sub 4-x}La{sub x}Ti{sub 4}O{sub 15} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Khokhar, Anita [Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India); Goyal, Parveen K., E-mail: goyalphy@gmail.com [Department of Physics, ARSD College, University of Delhi, Dhaula Kuan, New Delhi 110 021 (India); Thakur, O.P. [Electroceramics Group, Solid State Physics Laboratory, Lucknow Road, Delhi 110 054 (India); Shukla, A.K. [Department of Physics, Amity Institute of Applied Sciences, Amity University, Noida 201301 (India); Sreenivas, K., E-mail: kondepudysreenivas@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India)

    2015-02-15

    Structural and electrical properties of Lanthanum substituted barium bismuth titanate BaBi{sub 4-x}La{sub x}Ti{sub 4}O{sub 15} (0 ≤ x ≤ 0.50) ceramics prepared by conventional solid-state reaction method have been investigated. Raman spectra reveals the distribution of lanthanum into the perovskite layers and (Bi{sub 2}O{sub 2}){sup 2+} layers of BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics. Room temperature dielectric constant (ε′) increases and considerable reduction in the low frequency (10{sup −2} to 10 Hz) dielectric losses and in dc conductivity (σ{sub dc}) are seen with lanthanum substitution. A critical La content of x ∼0.20 in BaBi{sub 4-x}La{sub x}Ti{sub 4}O{sub 15} exhibits a well-defined relaxor behavior as seen from the temperature and frequency dependence of the dielectric parameters ε′(T) and ε″(T). The dielectric data fit well to the modified Curie–Weiss law and the Lorentz-type relation and show increasing diffuseness in the phase transition with increasing La content. The temperature dependence of the characteristic relaxation time obtained from the Cole–Cole model shows a good fit to the non-linear Vogel–Fulcher relation. Improvements in the remnant polarization and a stable piezoelectric charge coefficient are seen up to a La content of x ∼0.20. The observed increase in dielectric loss and σ{sub dc} in addition to the diminished ferroelectric/piezoelectric properties for higher La content are explained in terms of changing oxygen vacancy concentration and structural relaxation due to the preferential incorporation of La into the (Bi{sub 2}O{sub 2}){sup 2+} layers as evidenced through the Raman spectroscopy. - Highlights: • La distribution in BaBi{sub 4-x}La{sub x}Ti{sub 4}O{sub 15} ceramics is analyzed through Raman spectroscopy. • Low and a nearly constant loss over wide frequency range (10{sup −2}–10{sup 7} Hz) obtained. • Critical La content x = 0.2 identified for high resistivity and ideal relaxor

  10. Diffusion coefficients for Tl, Pb, Cd, In, Zn, Bi, As, Mo and Sb in hydrous rhyolite at 100-200 MPa

    Science.gov (United States)

    Berlo, Kim; Brooker, Richard; Wilke, Max

    2014-05-01

    A series of experiments have been conducted to determine the diffusivities of Tl, Pb, Cd, In, Zn, Bi, As, Mo and Sb in hydrous rhyolitic melt. Diffusion experiments used two adjoining glass cylinder of the same hydrous composition, one doped with the elements of interest at ~ 100 ppm. These couples were rapidly heated to 850, 1000 and 1150°C at 100-200 MPa for a few hours. After quenching the sectioned charges were analyzed by both synchrotron XRF (The Diamond Light Source) and LA-ICP-MS (University of Oxford). The data shows excellent correlation between these two techniques. The diffusion profiles were fitted to a 1-D diffusion couple equation to determine the diffusivities and fitting to the different temperature runs defined the Arrhenius parameters. We find that for 850°C the diffusion coefficients follow the trend Tl>Pb>Cd>Zn>In>Bi>As>Sb>Mo. Additional experiments were performed with either S or Cl added (to both sides of the diffusion couple). In general S increases the diffusion rate of all metals except Mo and Sb, which diffuse slower in the presence of S. Chlorine also speeds up the diffusion of metals with the exception of In, Mo and Sb. The systematic change in diffusivities of these metals and their different behaviour in the presence of the ligands that are also observed to be significant in volcanic gases, are important in determining the distribution of these metals during degassing (e.g. MacKenzie and Canil, 2008). This is particularly important in a dynamic environment such as a volcanic conduit. There are also implications for economic exploration and well as hazard mitigation.

  11. Comparative study for axial and radial shuffling scheme effect on the performance of Pb-Bi cooled fast reactors with natural uranium as fuel cycle input

    International Nuclear Information System (INIS)

    Zaki Suud; Indah Rosidah; Maryam Afifah; Ferhat Aziz; Sekimoto, H.

    2013-01-01

    Full text:Comparative study for the Design of Pb-Bi cooled fast reactors with natural uranium as fuel cycle input using special radial shuffling strategy and axial direction modified CANDLE burn-up scheme has been performed. The reactors utilizes UN-PuN as fuel, Eutectic Pb-Bi as coolant, and can be operated without refueling for 10 years in each batch. Reactor design optimization is performed to utilize natural uranium as fuel cycle input. This reactor subdivided into 6-10 regions with equal volume in radial directions. The natural uranium is initially put in region 1, and after one cycle of 10 years of burn-up it is shifted to region 2 and the region 1 is filled by fresh natural uranium fuel. This concept is basically applied to all regions. The calculation has been done by using SRAC-Citation system code and JENDL-3.2 library. The effective multiplication factor change increases monotonously during 10 years reactor operation time. There is significant power distribution change in the central part of the core during the BOC and the EOC in the radial shuffling system. It is larger than that in the case of modified CANDLE case which use axial direction burning region move. The burn-up level of fuel is slowly grows during the first 15 years but then grow faster in the rest of burn-up history. This pattern is a little bit different from the case of modified CANDLE burn-up scheme in Axial direction in which the slow growing burn-up period is relatively longer almost half of the burn-up history. (author)

  12. Educational experiment for university students using natural radioactivity. Development of an additional experiment to measure the increase in 214Pb and 214Bi produced from 222Rn

    International Nuclear Information System (INIS)

    Nakamura, Mariko; Esaka, Takao; Kamata, Masahiro

    2005-01-01

    Although several works have been published to date regarding radiochemistry, most of them have been designed for those who major in subjects related to chemistry or physics and use rather sophisticated methods and apparatus. Education about radiation and radioactivity is also very important for other students because a basic knowledge of radiation and radioactivity is indispensable for understanding environmental problems or energy problems in the future. However, it is not easy to conduct practical work using radioactivity in students' experiments at school or at university because the use of radioactivity is strictly regulated by the law, and equipment such as radiation counters is too expensive for school budgets. From such a viewpoint, we developed several kinds of safe and inexpensive experiments for education using natural radioactivity so that university (or senior high school) students can learn through their practical work without being regulated by the law. For this purpose, radioactive species belonging to the uranium decay series are suitable because these species can be easily obtained from mineral spring water or soil samples. In addition, some of the species such as 214 Pb and 214 Bi emit beta rays, which are easy to detect, and the half-lives of these which are easy to detect, and the half-lives of these elements can be measured in one or two-hour school activities. This kind of experiment was employed as an ''Educational experiment for radiochemistry'' at Tottori University for nearly fifty students every year. Although the experiment itself was essentially complete, the students did not have the chance to observe how radioactive equilibrium was established. Therefore, we have developed an additional work plan to enable students to observe how 214 Pb and 214 Bi are produced from 222 Rn, and have made this experiment more complete. The educational usefulness of this additional experiment was evaluated and will be presented in section 5. (author)

  13. The effect of Bi substitution on the microstructure and magnetic properties of the Sr0.4Ba0.3La0.3Fe12−xBixO19 hexagonal ferrites

    International Nuclear Information System (INIS)

    Yang, Yujie; Wang, Fanhou; Liu, Xiansong; Shao, Juxiang; Feng, Shuangjiu; Huang, Duohui; Li, Mingling

    2017-01-01

    Bi 3+ ions doped M-type hexaferrites, Sr 0.4 Ba 0.3 La 0.3 Fe 12−x Bi x O 19 (0≤x≤0.7), were prepared by the ceramic process. The phase components of the magnetic powders were investigated by X-ray diffraction. The results show that a single magnetoplumbite phase is obtained for the magnetic powders with x from 0 to 0.2, and BiFeO 3 as a second phase appears when Bi content (x)≥0.3. The micrographs of the sintered magnets were observed by a field emission scanning electron microscopy. The sintered magnets are formed of hexagonal-shaped crystals. The magnetic properties of the sintered magnets were measured at room temperature by a permanent magnetic measuring system. The remanence (B r ) first increases with x from 0 to 0.2, and then decreases when Bi content (x)≥0.2. The intrinsic coercivity (H cj ) and magnetic induction coercivity (H cb ) firstly decrease quickly with x from 0 to 0.1, and then increase linearly when Bi content (x)≥0.1. The maximum energy product [(BH) max ] increases with x from 0 to 0.3, and then decreases when Bi content (x)≥0.3. The ratio H k /H cj ratio first increases with Bi content (x) from 0 to 0.4. And the H k /H cj ratio decreases when x≥0.4. - Highlights: • Sr 0.4 Ba 0.3 La 0.3 Fe 12−x Bi x O 19 (0≤x≤0.7) hexaferrites were prepared by the ceramic process. • A single magnetoplumbite phase is obtained for the magnetic powders with x from 0 to 0.2. • B r first increases with x from 0 to 0.2, and then decreases when x≥0.2. • H cj and H cb firstly decrease quickly with x from 0 to 0.1, and then increase linearly when x≥0.1.

  14. Structural and electronic properties of Pb-doped Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}: Comparison of LDA and GGA calculations

    Energy Technology Data Exchange (ETDEWEB)

    Camargo-Martínez, J.A., E-mail: jcamargo@unitropico.edu.co [Grupo de Investigación en Ciencias Básicas, Aplicación e Innovación - CIBAIN, Fundación Universitaria Internacional del Trópico Americano– Unitrópico, Yopal, Casanare (Colombia); Martínez-Pieschacón, D.J. [Departamento de Ciencias Básicas, Universidad Santo Tomás, Tunja, Boyaca (Colombia); Baquero, R. [Departamento de Física, CINVESTAV-IPN, Av. IPN 2508, 07360, México (Mexico)

    2017-04-15

    Highlights: • We present for the first time the effects of Pb doping on structural and electronic properties of Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} (Bi2223) using GGA, compared with LDA results. • We found the Pb concentration for which the Bi–O pockets disappear from the Fermi Surface in the Bi2223 compound using GGA and LDA, respectively. - Abstract: We use Density Functional Theory to study the effects on the crystal structure and the electronic band structure of substituting Pb for Bi in Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}. We further use the Local Density Approximation (LDA) and the Generalized Gradient Approximation (GGA). The Virtual Crystal Approximation (VCA) was used to account for the substitution. We found that GGA reproduces better the lattice parameters although in both cases the internal coordinates were reproduced with some uncertainties. We further looked at the behavior of the so called Bi–O pockets, some electronic states that originate on the Bi–O planes and that appear on the Fermi surface (FS) in contradiction to the experimental evidence. We found that LDA and GGA differ on that subject. With 26% Pb and using LDA, the Bi–O pockets run away from the FS. But when GGA is used, it is needed up to 35% Pb to make the Bi–O pockets disappear from the FS. In the last case, once the Bi–O pockets are removed from the FS, we get a very good agreement with angular resolved photo-emission (ARPES) and nuclear magnetic resonance (NMR) experiments.

  15. Ceramic synthesis of 0.08BiGaO3-0.90BaTiO3-0.02LiNbO3 under high pressure and high temperature

    Science.gov (United States)

    Hui, Jin; Yong, Li; Mou-Sheng, Song; Lin, Chen; Xiao-Peng, Jia; Hong-An, Ma

    2016-07-01

    In this paper, the preparation of 0.08BiGaO3-0.90BaTiO3-0.02LiNbO3 is investigated at pressure 3.8 GPa and temperature 1100-1200 °C. Experimental results indicate that not only is the sintered rate more effective, but also the sintered temperature is lower under high pressure and high temperature than those of under normal pressure. It is thought that the adscititious pressure plays the key role in this process, which is discussed in detail. The composition and the structure of the as-prepared samples are recorded by XRD patterns. The result shows that the phases of BaTiO3, BaBiO2.77, and Ba2Bi4Ti5O18 with piezoelectric ceramic performance generate in the sintered samples. Furthermore, the surface morphology characteristics of the typical samples are also investigated using a scanning electron microscope. It indicates that the grain size and surface structure of the samples are closely related to the sintering temperature and sintering time. It is hoped that this study can provide a new train of thought for the preparation of lead-free piezoelectric ceramics with excellent performance. Project supported by the National Natural Science Foundation of China (Grant No. 51172089), the Natural Science Foundation of Education Department of Guizhou Province, China (Grant Nos. KY [2013]183 and LH [2015]7232), and the Research Fund for the Doctoral Program of Tongren University, China (Grant No. DS1302).

  16. A salt diapir-related Mississippi Valley-type deposit: the Bou Jaber Pb-Zn-Ba-F deposit, Tunisia: fluid inclusion and isotope study

    Science.gov (United States)

    Bouhlel, Salah; Leach, David L.; Johnson, Craig A.; Marsh, Erin; Salmi-Laouar, Sihem; Banks, David A.

    2016-08-01

    The Bou Jaber Ba-F-Pb-Zn deposit is located at the edge of the Bou Jaber Triassic salt diapir in the Tunisia Salt Diapir Province. The ores are unconformity and fault-controlled and occur as subvertical column-shaped bodies developed in dissolution-collapse breccias and in cavities within the Late Aptian platform carbonate rocks, which are covered unconformably by impermeable shales and marls of the Fahdene Formation (Late Albian-Cenomanian age). The host rock is hydrothermally altered to ankerite proximal to and within the ore bodies. Quartz, as fine-grained bipyramidal crystals, formed during hydrothermal alteration of the host rocks. The ore mineral assemblage is composed of barite, fluorite, sphalerite, and galena in decreasing abundance. The ore zones outline distinct depositional events: sphalerite-galena, barite-ankerite, and fluorite. Fluid inclusions, commonly oil-rich, have distinct fluid salinities and homogenization temperatures for each of these events: sphalerite-galena (17 to 24 wt% NaCl eq., and Th from 112 to 136 °C); ankerite-barite (11 to 17 wt% NaCl eq., and Th from 100 to 130 °C); fluorite (19 to 21 wt% NaCl eq., Th from 140 to 165 °C). The mean temperature of the ore fluids decreased from sphalerite (125 °C) to barite (115 °C) and increased during fluorite deposition (152 °C); then decreased to ˜110 °C during late calcite precipitation. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of fluid inclusions in fluorite are metal rich (hundreds to thousands ppm Pb, Zn, Cu, Fe) but the inclusions in barite are deficient in Pb, Zn, Cu, Fe. Inclusions in fluorite have Cl/Br and Na/Br ratios of several thousand, consistent with dissolution of halite while the inclusions analysed in barite have values lower than seawater which are indicative of a Br-enriched brine derived from evaporation plus a component of halite dissolution. The salinity of the barite-hosted fluid inclusions is less than obtained simply by the

  17. Effects of Sr2+ doping on the electrical properties of (Bi0.5Na0.50.94Ba0.06TiO3 ceramics

    Directory of Open Access Journals (Sweden)

    Amrita Singh

    2015-03-01

    Full Text Available The influence of SrTiO3 addition on the microstructure and various electrical properties of (Bi0.5Na0.50.94Ba0.06TiO3 (BNTBT6 ceramics, fabricated by a conventional high temperature solid state reaction, was investigated. Analysis of X-ray diffraction patterns revealed the formation of phase pure materials with tetragonal unit cell structure, tetragonality parameter c/a in the interval from 0.9940 to 1.0063 and crystallite sizes ranging from 33–76 nm for addition of 0.2 to 1 wt.% of SrTiO3. SEM studies indicated that Sr2+ doping led to decrease in grain size and non-homogeneity of grain distribution for higher SrTiO3 amount (>0.6 wt.%. Complex impedance, modulus, and conductivity studies indicated the presence of grains and grain boundary contribution, non-Debye type of relaxation and NTCR behaviour of the test ceramic samples. Temperature dependent real part of complex permittivity showed peaks at 475 °C and the dielectric loss tangent showed peaks corresponding to 125 °C and 475 °C for almost all compositions. AC activation energies, computed using Arrhenius relation in the temperature range of 325–500 °C for the BNTBT6 ceramic compositions having SrTiO3 concentration from 0.2 to 1.0 wt.%, were seen to have maximal values at the lowest measurement frequency. Amongst the different chosen doped BNTBT6 ceramic compositions, the composition having 0.6 wt.% of SrTiO3 showed the best ferroelectric and piezoelectric response with maximum value of Pr (8.24 µC/cm2, minimum value of Ec (5.73 kV/mm and maximum d33 value (∼46 pC/N.

  18. Structural, spectroscopic, and dielectric characterizations of Mn-doped 0.67BiFeO3-0.33BaTiO3 multiferroic ceramics

    KAUST Repository

    Hang, Qiming

    2013-09-07

    0.67BiFeO3-0.33BaTiO3 multiferroic ceramics doped with x mol% MnO2 (x = 2–10) were synthesized by solid-state reaction. The formation of a perovskite phase with rhombohedral symmetry was confirmed by X-ray diffraction (XRD). The average grain sizes were reduced from 0.80 μm to 0.50 μm as increasing the Mn-doped levels. Single crystalline nature of the grains was revealed by high-resolution transmission electron microscopy (HRTEM) images and electron diffraction patterns. Polar nano-sized ferroelectric domains with an average size of 9 nm randomly distributed in the ceramic samples were revealed by TEM images. Ferroelectric domain lamellae (71° ferroelectric domains) with an average width of 5 nm were also observed. Vibrational modes were examined by Raman spectra, where only four Raman peaks at 272 cm−1 (E-4 mode), 496 cm−1 (A 1-4 mode), 639 cm−1, and 1338 cm−1 were observed. The blue shifts in the E-4 and A 1-4 Raman mode frequencies were interpreted by a spring oscillator model. The dieletric constants of the present ceramics as a function of the Mn-doped levels exhibited a V-typed curve. They were in the range of 350–700 measured at 103 Hz, and the corresponding dielectric losses were in range of 0.43–0.96, approaching to 0.09 at 106 Hz.

  19. Structural, spectroscopic, and dielectric characterizations of Mn-doped 0.67BiFeO3-0.33BaTiO3 multiferroic ceramics

    KAUST Repository

    Hang, Qiming; Zhou, Wenke; Zhu, Xinhua; Zhu, Jianmin; Liu, Zhiguo; Al-Kassab, Talaat

    2013-01-01

    0.67BiFeO3-0.33BaTiO3 multiferroic ceramics doped with x mol% MnO2 (x = 2–10) were synthesized by solid-state reaction. The formation of a perovskite phase with rhombohedral symmetry was confirmed by X-ray diffraction (XRD). The average grain sizes were reduced from 0.80 μm to 0.50 μm as increasing the Mn-doped levels. Single crystalline nature of the grains was revealed by high-resolution transmission electron microscopy (HRTEM) images and electron diffraction patterns. Polar nano-sized ferroelectric domains with an average size of 9 nm randomly distributed in the ceramic samples were revealed by TEM images. Ferroelectric domain lamellae (71° ferroelectric domains) with an average width of 5 nm were also observed. Vibrational modes were examined by Raman spectra, where only four Raman peaks at 272 cm−1 (E-4 mode), 496 cm−1 (A 1-4 mode), 639 cm−1, and 1338 cm−1 were observed. The blue shifts in the E-4 and A 1-4 Raman mode frequencies were interpreted by a spring oscillator model. The dieletric constants of the present ceramics as a function of the Mn-doped levels exhibited a V-typed curve. They were in the range of 350–700 measured at 103 Hz, and the corresponding dielectric losses were in range of 0.43–0.96, approaching to 0.09 at 106 Hz.

  20. Giant electrical conductivity enhancement in BaO-V{sub 2}O{sub 5}-Bi{sub 2}O{sub 3} glass by nanocrystallization

    Energy Technology Data Exchange (ETDEWEB)

    El-Desoky, M.M., E-mail: mmdesoky@gmail.com [Department of Physics, Faculty of Education, Suez Canal University, Al-Arish (Egypt)

    2010-02-15

    The effects of the annealing of 20BaO-30V{sub 2}O{sub 5}-50Bi{sub 2}O{sub 3} glass on the structural and electrical properties were studied by scanning electron micrographs (SEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC) density (d) and dc conductivity ({sigma}). The XRD and SEM observations have shown that the sample under study undergoes structural changes: from amorphous at the beginning, to partly crystalline after nanocrystallization at crystallization temperature (T{sub c}) for 1 h and to colossal crystallization after the annealing at the same temperature for 24 h. The average size of these grains after nanocrystallization at T{sub c} for 1 h was estimated to be about 25-35 nm. However, the glass heat treated at T{sub c} = 580 deg. C for 24 h the microstructure changes considerably. The nanomaterials obtained by nanocrystallization at T{sub c} for 1 h exhibit giant improvement of electrical conductivity up to four order of magnitude and better thermal stability than the as-received glass. The major role in the conductivity enhancement of this nanomaterial is played by the developed interfacial regions 'conduction tissue' between crystalline and amorphous phases, in which the concentration of V{sup 4+}-V{sup 5+} pairs responsible for electron hopping is higher than inside the glassy matrix. The annealing at T{sub c} for 24 h leads to decrease of the electronic conductivity. This phenomena lead to disappearance of the abovementioned 'conduction tissue' for electrons and substantial reduction of electronic conductivity. The high temperature (above {theta}/2) dependence of conductivity could be qualitatively explained by the small polaron hopping (SPH) model. The physical parameters obtained from the best fits of this model are found reasonable and consistent with the glass compositions.

  1. Heat Treatment Effect on Eu3+ Doped TeO2-BaO-Bi2O3 Glass Systems with Ag Nanoparticles

    Directory of Open Access Journals (Sweden)

    Tomasz Lewandowski

    2017-01-01

    Full Text Available Glass systems of 73TeO2-4BaO-3Bi2O3-2Eu2O3-xAg (in molar ratio where x = 0, 1, 2, and 3 compositions have been successfully synthesized. Silver nanoparticles were obtained with the employment of heat treatment (HT procedure executed at 350°C. Glass transition temperatures of different compositions have been determined through DSC measurements. XRD results presented characteristic amorphous halo indicating lack of long range order in the samples. FTIR structural studies revealed that glass matrix is mainly composed of TeO3 and TeO4 species and is stable after different applied heat treatment times. X-ray photoelectron spectroscopy (XPS measurements confirmed that in selected samples part of Ag ions changed oxidation state to form Ag0 species. TEM measurements revealed nanoparticles of size in the range of 20–40 nm. UV-vis absorption results demonstrated characteristic transitions of Eu3+ ions. Additionally, UV-vis spectra of samples heat-treated for 6, 12, 24, and 48 hours presented bands related to silver nanoparticles. Photoluminescence (PL studies have been performed with excitation wavelength of λexc=395 nm. Obtained spectra exhibited peaks due to 5D0-7FJ (where J=2,3,4 and 5D1-7FJ (where J=1,2,3 transitions of Eu3+. Moreover, luminescence measurement indicated enhancement of rare earth ions emissions in several of the annealed samples. Increase of emission intensity of about 35% has been observed.

  2. Raman scattering intensities in BaTiO3 and PbTiO3 prototypical ferroelectrics from density functional theory

    International Nuclear Information System (INIS)

    Hermet, P; Veithen, M; Ghosez, Ph

    2009-01-01

    Nonlinear optical susceptibilities and Raman scattering spectra of the ferroelectric phases of BaTiO 3 and PbTiO 3 are computed using a first-principles approach based on density functional theory and taking advantage of a recent implementation based on the nonlinear response formalism and the 2n+1 theorem. These two prototypical ferroelectric compounds were chosen to demonstrate the accuracy of the Raman calculation based both on their complexity and their technological importance. The computation of the Raman scattering intensities has been performed not only for the transverse optical modes, but also for the longitudinal optical ones. The agreement between the measured and computed Raman spectra of these prototypical ferroelectrics is remarkable for both the frequency position and the intensity of Raman lines. This agreement presently demonstrates the state-of-the-art in the computation of Raman responses on one of the most complex systems, ferroelectrics, and constitutes a step forward in the reliable prediction of their electro-optical responses.

  3. Ferroelectric properties of BaTiO3/PbZr0.2Ti.08O3 bilayer thin film

    Science.gov (United States)

    Salev, Pavel; Yang, Chun; Grigoriev, Alexei

    2014-03-01

    The thin film ferroelectric BaTiO3/PbZr0.2Ti0.8O3 bilayer was epitaxially grown on SrRuO3/SrTiO3 substrate by RF sputtering. Electrical measurements of polarization switching revealed two different switching regimes - a small ferroelectric hysteresis loop at low applied voltage and a larger loop at a high voltage. The measured dielectric permittivity corresponds to weak electrostatic coupling between two layers according to Landau-Ginsburg-Devonshire theory. This weak coupling may allow for independent polarization states to exist in individual layers. This can lead to stable head-to-head and tail-to-tail polarization domain configurations, which would explain the two switching regimes observed in electrical measurements. The compensation of polarization gradient across the interface can be explained by the enhancement of interface charge carrier density due to strong bending of electron energy bands. This work was supported by NSF award DMR-1057159.

  4. Phase development and dielectric properties of (1-x)Pb(Zr0.52Ti0.48)O3-xBaTiO3 ceramics

    International Nuclear Information System (INIS)

    Chaisan, Wanwilai; Yimnirun, Rattikorn; Ananta, Supon; Cann, David P.

    2006-01-01

    (1-x)Pb(Zr 0.52 Ti 0.48 )O 3 -xBaTiO 3 ceramics were prepared by a modified mixed-oxide method. The phase formation was studied by XRD analysis. All compositions exhibit complete solid solutions of perovskite-like phase in the (1-x)PZT-xBT system. The (2 0 0)/(0 0 2) peak was found to split at the composition x = 0.6 and the co-existence of tetragonal-rhombohedral phases occurs with x ≤ 0.6. The possible range of compositions which correspond to a phase transition is 0.6 < x < 0.7. While pure BT ceramics exhibited a sharp phase transformation expected for normal ferroelectrics, phase transformation behavior of the (1-x)PZT-xBT solid solutions became more diffuse with increasing BT contents. This was primarily evidenced by an increased broadness in the dielectric peak, with a maximum peak width occurring at x = 0.5

  5. U-Pb zircon geochronology of intrusive and basement rocks in the Jacurici Valley region, Sao Francisco Craton, BA, Brazil

    International Nuclear Information System (INIS)

    Silveira, Carlos Jose Sobrinho da; Frantz, Jose Carlos; Marques, Juliana Charao; Roos, Siegbert; Peixoto, Vinicius Medina

    2015-01-01

    The Jacurici Complex, located in the NE of the Sao Francisco Craton, is constituted by several Cr-mineralized mafic-ultramafic N-S bodies, possible fragments of a single sill disrupted during deformation. Some works suggest it is intruded on the Serrinha Block while others consider it in the Salvador-Curaca Belt. The basement on this region is informally divided into paragneisses and orthogneisses; the latter is supposed to be younger considering it is less deformed. Petrography revealed that some of the paragneisses are alkali-feldspar granite strongly milonitized. The orthogneisses occur at the north and consist, at least in part, of monzogranites with heterogeneous deformation, locally of low temperature. U-Pb zircon dating were performed for five representative samples. Just three provided good concordia ages. A mafic rock produced a 2102 ± 5 Ma age and it is petrographically similar to the metanorites described in the Jacurici Complex, being interpreted as the record of the first pulses of the mafic magmatism. A monzogranite yielded a 2995 ± 15 Ma age, older than expected, related to the Serrinha Block. The alkali-feldspar granite yielded a 2081 ± 3 Ma age. The Itiuba Syenite and the pegmatites that crosscut the Jacurici Complex have similar ages. Considering the lack of information about the supracrustal sequence that hosts the intrusive alkaline and mafic-ultramafic rocks at the Ipueira and the Medrado areas, it is possible that part of the terrain belongs to the Salvador-Curaca Belt. We suggest that the Jacurici Complex could be intruded after the tectonic amalgamation between the Serrinha Block and the older part of the Salvador-Curaca Belt and, therefore, could be hosted by both terrains. (author)

  6. Solubility of uranovanadates of the series A2+(VUO6)2 · nH2O (A2+ = Mg, Ca, Sr, Ba, Co, Ni, Cu, Pb) in water or aqueous solutions

    International Nuclear Information System (INIS)

    Chernorukov, N.G.; Sulejmanov, E.V.; Nipruk, O.V.; Lizunova, G.M.

    2001-01-01

    Solubility of uranovanadates of the series A 2+ (VUO 6 ) 2 · nH 2 O (A 2+ - Mg, Ca, Sr, Ba, Co, Ni, Cu, Pb) in water and aqueous solutions of inorganic acids at 25 deg C and different pH values was determined experimentally. The data obtained permitted calculation the Gibbs standard functions of formation and consideration of their state under conditions that were not studied experimentally, in the presence of carbon dioxide, in particular [ru

  7. Chemical and structural effects on the high-temperature mechanical behavior of (1−x)(Na{sub 1/2}Bi{sub 1/2})TiO{sub 3}-xBaTiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Deluca, Marco [Materials Center Leoben Forschung GmbH, Roseggerstraße 12, 8700 Leoben (Austria); Institut für Struktur- und Funktionskeramik, Montanuniversitaet Leoben, Peter Tunner Straße 5, 8700 Leoben (Austria); Picht, Gunnar [Institute of Applied Materials, Ceramics in Mechanical Engineering, Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Robert Bosch GmbH, Corporate Sector Research and Advance Engineering Applied Research 1, Robert Bosch Platz 1, 70839 Gerlingen (Germany); Hoffmann, Michael J. [Institute of Applied Materials, Ceramics in Mechanical Engineering, Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Rechtenbach, Annett; Töpfer, Jörg [Department of SciTec, University of Applied Sciences Jena, Carl-Zeiß-Promenade 2, 07745 Jena (Germany); Schader, Florian H.; Webber, Kyle G., E-mail: webber@ceramics.tu-darmstadt.de [Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany)

    2015-04-07

    Bismuth sodium titanate–barium titanate [(1−x)(Na{sub 1/2}Bi{sub 1/2})TiO{sub 3}-xBaTiO{sub 3}, NBT-100xBT] is one of the most well studied lead-free piezoelectric materials due in large part to the high field-induced strain attainable in compositions near the morphotropic phase boundary (x = 0.06). The BaTiO{sub 3}-rich side of the phase diagram, however, has not yet been as comprehensively studied, although it might be important for piezoelectric and positive temperature coefficient ceramic applications. In this work, we present a thorough study of BaTiO{sub 3}-rich NBT-100xBT by ferroelastic measurements, dielectric permittivity, X-ray diffraction, and Raman spectroscopy. We show that the high-temperature mechanical behavior, i.e., above the Curie temperature, T{sub C}, is influenced by local disorder, which appears also in pure BT. On the other hand, in NBT-100xBT (x < 1.0), lattice distortion, i.e., tetragonality, increases, and this impacts both the mechanical and dielectric properties. This increase in lattice distortion upon chemical substitution is counterintuitive by merely reasoning on the ionic size, and is due to the change in the A-O bond character induced by the Bi{sup 3+} electron lone pair, as indicated by Raman spectroscopy.

  8. Positron annihilation study of the high-Tc (Bi, Pb)2Sr2Ca2Cu3Ox superconductor

    International Nuclear Information System (INIS)

    Lim, H.J.; Byrne, J.G.

    1997-01-01

    Positron lifetime spectroscopy (PLS) and positron Doppler-broadening spectroscopy (PDBS) were applied to the high-T c lead-doped Bi 2 Sr 2 Ca 2 Cu 3 O x (BPSCCO 2223) superconductor as a function of temperature. Neither positron lifetimes nor Doppler parameters (S, W, and S/W) showed significant change through T c . This may result from having the highest positron density in the open BiO 2 double layers and no significant positron density in the superconducting CuO 2 layers where positrons, if mainly present, are known to be sensitive to the transition in other high-T c superconductors. Doppler parameters showed that the probability of positron annihilations with core electrons in the lattice slightly increased and that the probability of positron annihilations with conduction electrons slightly decreased as temperature decreased from ambient temperature to 20 K. The lifetime associated with positron annihilations in the perfect lattice of the sample (τ 1 ) was 209 ps and, due to the annihilations at internal surfaces or voids in the sample (τ 2 ) was about 540 ps, independent of temperature. Finally, the mean lifetime for BSCCO 2223 was about 307 ps. (orig.)

  9. Ore horizons, ore facies, mineralogy and geochemistry of volconogenic massive sulfide (VMS deposits of the Varandan Ba-Pb-Cu deposit, southwest of Qamsar - Iran

    Directory of Open Access Journals (Sweden)

    Fayeq Hashemi

    2017-11-01

    Full Text Available Introduction The Varandan Ba-Pb-Cu deposits are located15 km southwest of the town of Qamsar and approximately 7 km south west of the Qazaan village, in the Urumieh- Dokhtar magmatic arc. The Kashan region that is situated in west-central Iran hosts several barite-base metal deposits and occurrences, the biggest ones are the Varandan Ba-Pb-Cu (case considered in this study and the Tapeh-Sorkh (Khalajmaasomi et al., 2010 and Dorreh Ba (Nazari, 1994 deposits. Previous researchers (Izadi, 1996; Farokhpey et al., 2010 have proposed an epithermal model for formation of the Varandan deposit. However, based on some feature of the deposit, it seems that this genetic model may not be correct. Therefore, it is necessary to do more precise research studies on the deposit. The main purpose of this paper is to discuss the genesis of the Varandan deposit based on geological, ore facies, mineralogy, wall rock alterations, and geochemical studies. Materials and methods A field study and sampling was performed during the summer of 2013. To assess the geochemical characteristics of the deposit, about 17 systematic samples from different ore facies of the first, second and third sub-horizon were collected for petrography and mineralogy, and for inductively coupled plasma-atomic emission spectroscopy(ICP-AES, X-ray diffraction (XRD and X-ray fluorescence (XRF geochemical analysis methods. The microscopic studies were done in the optics laboratory of the Shahrood University, and the geochemical analyzes were conducted in laboratories of the Center of Research and Mineral Processing Ore Minerals of Iran, Karaj, Iran. Results The host sequence in the Varandan deposit involves three units, from bottom to top: Unit1: grey, green siliceous tuff, brecciated tuff, crystal tuff and andesite; Unit2: white grey nummulitic limestone, limy tuff and marl: and Unit3: tuff breccia and crystal lithic tuff. Mineralization in the Varandan deposit has occurred as four ore sub

  10. Adsorption-controlled growth of ferroelectric PbTiO{sub 3} and Bi{sub 4}Ti{sub 3}O{sub 12} films for nonvolatile memory applications by MBE

    Energy Technology Data Exchange (ETDEWEB)

    Theis, C.D.; Yeh, J.; Schlom, D.G. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering; Hawley, M.E.; Brown, G.W. [Los Alamos National Lab., NM (United States). Center for Materials Science

    1997-09-01

    Epitaxial PbTiO{sub 3} and Bi{sub 4}Ti{sub 3}O{sub 12} thin films have been grown on (100) SrTiO{sub 3} and (100) LaAlO{sub 3} substrates by reactive molecular beam epitaxy (MBE). Titanium is supplied to the film in the form of shuttered bursts each containing a one monolayer dose of titanium atoms for the growth of PbTiO{sub 3} and three monolayers for the growth of Bi{sub 4}Ti{sub 3}O{sub 12}. Lead, bismuth, and ozone are continuously supplied to the surface of the depositing film. Growth of phase pure, c-axis oriented epitaxial films with bulk lattice constants is achieved using an overpressure of these volatile species. With the proper choice of substrate temperature (600--650 C) and ozone background pressure (P{sub O{sub 3}} = 2 {times} 10{sup {minus}5} Torr), the excess of the volatile metals and ozone desorb from the surface of the depositing film leaving a phase-pure stoichiometric crystal. The smooth PbTiO{sub 3} surface morphology revealed by atomic force microscopy (AFM) suggests that the PbTiO{sub 3} films grow in a layer-by-layer fashion. In contrast the Bi{sub 4}Ti{sub 3}O{sub 12} films contain islands which evolve either continuously or around screw dislocations via a spiral-type growth mechanism.

  11. Monitoramento da qualidade físico-química da água do estuário do Rio Paraíba – Cabedelo, PB

    Directory of Open Access Journals (Sweden)

    Liz Jully Hiluey Correia

    2015-12-01

    Full Text Available Este trabalho teve como objetivo realizar o monitoramento da qualidade da água do estuário do Rio Paraíba, a fim de subsidiar ações de proteção e/ou recuperação do ambiente aquático, além de sinalizar o potencial risco de contaminação dos mariscos. O estudo foi desenvolvido em área de extração de mariscos, localizada no Rio Paraíba, em Cabedelo-PB. As amostras foram coletadas em triplicata, em seis pontos, entre os meses de maio e agosto de 2014. Os parâmetros (temperatura, turbidez, pH, condutividade elétrica, oxigênio dissolvido (OD, amônia, nitrito e fosfato foram avaliados seguindo a metodologia do APHA (1998. Os resultados ratificam a existência de atividades causadoras da elevada concentração do teor de amônia e do baixo nível de OD no ambiente aquático. A dinâmica da maré e as condições físicas do ambiente aceleraram a reação de nitrificação. As concentrações de fosfato e nitrito estiveram dentro do limite máximo estabelecido na resolução n° 357/05 do CONAMA. Tendo em vista a potencialização dos riscos de contaminação dos mariscos devido à poluição hídrica, faz-se necessária uma intervenção dos órgãos fiscalizadores quanto ao lançamento direto de resíduos sólidos e líquidos no estuário, de forma a garantir a integridade do ambiente aquático e a saúde dos consumidores.

  12. Transição de Fase Difusa e Propriedades Dielétricas de Cerâmicas Ferroelétricas de (Pb, BaNb2O6

    Directory of Open Access Journals (Sweden)

    I.A. Santos

    2002-03-01

    Full Text Available Tungsten bonze structured lead barium niobate (Pb1-xBa xNb2O6 ferroelectric ceramics were prepared by the conventional mixed oxide method and their dielectric properties were carefully investigated. All studied samples presented elevated values of maximum dielectric constant (epsilon'm and its corresponding temperature of maximum (Tm in comparison with perovskite structured ones. The phase transition features indicate that the PBN samples do not present a complete diffuse phase transition. Indeed, the diffuseness degree of the ferroelectric phase transition is highly dependent of the ions Pb2+ content in the sample compositions. The diffuseness of the ferroelectric phase transition is enhanced while the temperature of maximum dielectric constant is decreased with the Pb2+ content decreasing. In addition, the maximum dielectric constant shows an opposite behavior.

  13. Texturing of superconducting Bi-Pb-Sr-Ca-Cu-O ceramics by combining the effect of a magnetic field and hot pressing in one direction; Texturation des ceramiques supraconductrices Bi-Pb-Sr-Ca-Cu-O par combinaison des effets du champ magnetique et de la contrainte uniaxiale a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Noudem, J G

    1995-10-27

    Superconducting Bi-(Pb)-Sr-Ca-Cu-O (Bi:2223) ceramics have a weak 77 K transport critical current density (Jc) due to porosity and the presence of misaligned platelets. In order to obtain higher critical current densities in these materials, it is necessary to increase their density and induce a preferential crystallographic orientation. We have developed a texturing process using solidification in a magnetic field combined with hot pressing. The experimental set-up provides a uniaxial pressure of 60 MPa and temperature up to 1100 deg C in a magnetic field of 8 T. Magnetic melt texturing (MMT) proved to be very effective in producing bulk oriented samples of polycrystalline Bi:2223 (crystallite c-axis oriented parallel to the field direction). These samples have Jc values of up to 1450 A/cm{sup 2} and a density of 5.1 g/cm{sup 3}. The texturing by hot pressing (HP) gives homogeneous, dense ({approx} 6 g/cm{sup 3}; 95 % of the theoretical limit) ceramics with a Jc of 2500 A/cm{sup 2}. Tapes of Ag/Bi:2223 provided by Alcatel Alsthom were also successful textured using HP. Finally we have demonstrated that the combination of solidification in a magnetic field with hot pressing (MMHPT) improves both the texture and density of the samples. Moreover the samples are very homogeneous and mechanically resistant. The 77 K transport critical current densities have values up to 3800 A/cm{sup 2} and 1100 A/cm{sup 2} along the (ab) and c-axis respectively. We have demonstrated that these samples are of potential use a current limiters. (author) 146 refs.

  14. Low-temperature specific heat of single-crystal Bi2CaSr2Cu2O8 and Tl2Ca2Ba2Cu3O10

    Science.gov (United States)

    Urbach, J. S.; Mitzi, D. B.; Kapitulnik, A.; Wei, J. Y. T.; Morris, D. E.

    1989-06-01

    We report specific-heat measurements from 2 to 15 K on single crystals of Bi2CaSr2Cu2O8 and Tl2Ca2Ba2Cu3O10 We find low-temperature deviations from the Debye law that can be attributed to spin-glass behavior of a small concentration of isolated impurity copper moments. At higher temperatures, we observe contributions to the specific heat that can be attributed to a soft-phonon mode, possibly associated with the superstructure in the Bi-O and Tl-O layers. From our single-crystal data, we conclude that the thallium- and bismuth-based copper oxide superconductors show no measurable linear term in the specific heat [γ(0)<=1 mJ/mole K2].

  15. Low-temperature specific heat of single-crystal Bi2CaSr2Cu2O8 and Tl2Ca2Ba2Cu3O10

    International Nuclear Information System (INIS)

    Urbach, J.S.; Mitzi, D.B.; Kapitulnik, A.; Wei, J.Y.T.; Morris, D.E.; Physics Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720)

    1989-01-01

    We report specific-heat measurements from 2 to 15 K on single crystals of Bi 2 CaSr 2 Cu 2 O 8 and Tl 2 Ca 2 Ba 2 Cu 3 O 10 We find low-temperature deviations from the Debye law that can be attributed to spin-glass behavior of a small concentration of isolated impurity copper moments. At higher temperatures, we observe contributions to the specific heat that can be attributed to a soft-phonon mode, possibly associated with the superstructure in the Bi-O and Tl-O layers. From our single-crystal data, we conclude that the thallium- and bismuth-based copper oxide superconductors show no measurable linear term in the specific heat [γ(0) less than or equal to 1 mJ/mole K 2

  16. Improvement of critical current density in thallium-based (Tl,Bi)Sr{sub 1.6}Ba{sub 0.4}Ca{sub 2}Cu{sub 3}O{sub x} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Z.F.; Wang, C.A.; Wang, J.H. [State Univ. of New York at Buffalo, Amherst, NY (United States)] [and others

    1994-12-31

    Epitaxial (Tl,Bi)Sr{sub 1.6}Ba{sub 0.4}Ca{sub 2}Cu{sub 3}O{sub x} (Tl,Bi)-1223 thin films on (100) single crystal LaAlO{sub 3} substrates were synthesized by a two-step procedure. Phase development, microstructure, and relationships between film and substrate were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Resistance versus temperature, zero-field-cooled and field-cooled magnetization, and transport critical current density (J{sub c}) were measured. The zero-resistance temperature was 105-111 K. J{sub c} at 77 K and zero field was > 2 x 10{sup 6} A/cm{sup 2}. The films exhibited good flux pinning properties.

  17. A salt diapir-related Mississippi Valley-type deposit: The Bou Jaber Pb-Zn-Ba-F deposit, Tunisia: Fluid inclusion and isotope study

    Science.gov (United States)

    Bouhlel, Salah; Leach, David; Johnson, Craig A.; Marsh, Erin; Salmi-Laouar, Sihem; Banks, David A.

    2016-01-01

    The Bou Jaber Ba-F-Pb-Zn deposit is located at the edge of the Bou Jaber Triassic salt diapir in the Tunisia Salt Diapir Province. The ores are unconformity and fault-controlled and occur as subvertical column-shaped bodies developed in dissolution-collapse breccias and in cavities within the Late Aptian platform carbonate rocks, which are covered unconformably by impermeable shales and marls of the Fahdene Formation (Late Albian–Cenomanian age). The host rock is hydrothermally altered to ankerite proximal to and within the ore bodies. Quartz, as fine-grained bipyramidal crystals, formed during hydrothermal alteration of the host rocks. The ore mineral assemblage is composed of barite, fluorite, sphalerite, and galena in decreasing abundance. The ore zones outline distinct depositional events: sphalerite-galena, barite-ankerite, and fluorite. Fluid inclusions, commonly oil-rich, have distinct fluid salinities and homogenization temperatures for each of these events: sphalerite-galena (17 to 24 wt% NaCl eq., and Th from 112 to 136 °C); ankerite-barite (11 to 17 wt% NaCl eq., and Th from 100 to 130 °C); fluorite (19 to 21 wt% NaCl eq., Th from 140 to 165 °C). The mean temperature of the ore fluids decreased from sphalerite (125 °C) to barite (115 °C) and increased during fluorite deposition (152 °C); then decreased to ∼110 °C during late calcite precipitation. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of fluid inclusions in fluorite are metal rich (hundreds to thousands ppm Pb, Zn, Cu, Fe) but the inclusions in barite are deficient in Pb, Zn, Cu, Fe. Inclusions in fluorite have Cl/Br and Na/Br ratios of several thousand, consistent with dissolution of halite while the inclusions analysed in barite have values lower than seawater which are indicative of a Br-enriched brine derived from evaporation plus a component of halite dissolution. The salinity of the barite-hosted fluid inclusions is less than obtained

  18. Preparation and electrical properties of Bi0.5Na0.5TiO3-BaTiO3-KNbO3 lead-free piezoelectric ceramics

    International Nuclear Information System (INIS)

    Ni Haimin; Luo Laihui; Li Weiping; Zhu Yuejin; Luo Haosu

    2011-01-01

    Research highlights: → Bi 0.47 Na 0.47 Ba 0.06 TiO 3 -KNbO 3 ceramics exhibit excellent piezoelectric properties. → The optimized properties of the ceramics: d 33 = 195 pC/N; k t = 58.9; Q m = 113; E c = 19.5 kV/cm. → KNbO 3 has diffused into the Bi 0.47 Na 0.47 Ba 0.06 TiO 3 lattices to form a new solid solution. → Macro-micro domain switching occurs at depolarization temperature T d . - Abstract: Lead-free (1 - x)Bi 0.47 Na 0.47 Ba 0.06 TiO 3 -xKNbO 3 (BNBT-xKN, x = 0-0.08) ceramics were prepared by ordinary ceramic sintering technique. The piezoelectric, dielectric and ferroelectric properties of the ceramics are investigated and discussed. The results of X-ray diffraction (XRD) indicate that KNbO 3 (KN) has diffused into Bi 0.47 Na 0.47 Ba 0.06 TiO 3 (BNBT) lattices to form a solid solution with a pure perovskite structure. Moderate additive of KN (x ≤ 0.02) in BNBT-xKN ceramics enhance their piezoelectric and ferroelectric properties. Three dielectric anomaly peaks are observed in BNBT-0.00KN, BNBT-0.01KN and BNBT-0.02KN ceramics. With the increment of KN in BNBT-xKN ceramics, the dielectric anomaly peaks shift to lower temperature. BNBT-0.01KN ceramic exhibits excellent piezoelectric properties and strong ferroelectricity: piezoelectric coefficient, d 33 = 195 pC/N; electromechanical coupling factor, k t = 58.9 and k p = 29.3%; mechanical quality factor, Q m = 113; remnant polarization, P r = 41.8 μC/cm 2 ; coercive field, E c = 19.5 kV/cm.

  19. Texturation à froid sous contraintes triaxiales de phase à haute T_c de Bi(Pb)SrCaCuO préréagie

    Science.gov (United States)

    Langlois, P.; Massat, H.; Suryanarayanan, R.

    1994-11-01

    The alignment of grains in isostatically precompacted samples of prereacted Bi{1,8}Pb{0,4}Sr{2,0}Ca{2,2}Cu{3,0}O{10,3 + x} powder has been achieved by compressive plastic deformation under isostatic pressure at room temperature. Isostatic pressures were in the range 0.1 to 1 GPa and deformation rates were led up to 57 %. Prior to sintering, X-ray diffraction measurements corroborate an expected high- T_c phase purity of nearly 85 % and indicate that the as-deformed samples have been textured with the (c-axes parallel to the pressing direction whilst a.c. susceptibility measurements ascertain a high transition temperature around 107 K. Intergranular connection does not occur until sintering at 850 ^{circ}C for 80 h and measurements indicate then that the texture has been retained. Superconducting properties themselves show sensitivity to texture through anisotropy-related distinctive irreversibility lines. L'alignement de grains de poudre Bi{1,8}Pb{0,4}Sr{2,0}Ca{2,2}Cu{3,0}O{10,3 + x} préréagie a été réalisé par déformation plastique à température ambiante d'échantillons précompactés isostatiquement et comprimés sous pression isostatique, la gamme des pressions isostatiques allant de 0,1 à 1 GPa et les taux de déformation atteignant 57 %. Les mesures de diffraction de rayons X corroborent la pureté de phase à haute T_c proche de 85 % attendue et indiquent que les échantillons ainsi déformés ont été texturés avec les plans ab perpendiculaires à la direction de compression. Les mesures de susceptibilité alternative avèrent une température élevée de transition à environ 107 K mais la connexion intergranulaire n'est assurée qu'après un frittage à 850 ^{circ}C pendant 80 h dont on vérifie qu'il conserve la texture. Enfin, la sensibilité des propriétés supraconductrices à la texturation est évaluée par le biais de lignes d'irréversibilité distinctes en fonction de l'anisotropie.

  20. Pathways for the release of polonium from a lead-bismuth spallation target (thermochemical calculation); Verfluechtigungspfade des Poloniums aus einem Pb-Bi-Spallationstarget (Thermochemische Kalkulation)

    Energy Technology Data Exchange (ETDEWEB)

    Eichler, B.; Neuhausen, J

    2004-06-01

    An analysis of literature data for the thermochemical constants of polonium reveals considerable discrepancies in the relations of these data among each other as well as in their expected trends within the chalcogen group. This fact hinders a reliable assessment of possible reaction paths for the release of polonium from a liquid lead-bismuth spallation target. In this work an attempt is made to construct a coherent data set for the thermochemical properties of polonium and some of its compounds that are of particular importance with respect to the behaviour of polonium in a liquid Pb-Bi target. This data set is based on extrapolations using general trends throughout the periodic table and, in particular, within the chalcogen group. Consequently, no high accuracy should be attributed to the derived data set. However, the data set derived in this work is consistent with definitely known experimental data. Furthermore, it complies with the general trends of physicochemical properties within the chalcogen group. Finally, well known relations between thermochemical quantities are fulfilled by the data derived in this work. Thus, given the lack of accurate experimental data it can be regarded as best available data. Thermochemical constants of polonium hydride, lead polonide and polonium dioxide are derived based on extrapolative procedures. Furthermore, the possibility of formation of the gaseous intermetallic molecule BiPo, which has been omitted from discussion up to now, is investigated. From the derived thermochemical data the equilibrium constants of formation, release and dissociation reactions are calculated for different polonium containing species. Furthermore equilibrium constants are determined for the reaction of lead polonide and polonium dioxide with hydrogen, water vapour and the target components lead and bismuth. The most probable release pathways are discussed. From thermochemical evaluations polonium is expected to be released from liquid lead

  1. Structural and Moessbauer Effect Studies of 0.5Bi0.95Dy0.05FeO3-0.5Pb(Fe2/3W1/3)O3 Multiferroic

    International Nuclear Information System (INIS)

    Stoch, A.; Zachariasz, P.; Stoch, P.; Kulawik, J.; Maurin, J.

    2011-01-01

    A polycrystalline ceramic of 0.5Bi 0.95 Dy 0.05 FeO 3 -0.5Pb(Fe 2/3 W 1/3 )O 3 was synthesized from a solid-state reaction method. At room temperature material exhibits both magnetic and electric dipolar properties simultaneously. Detailed X-ray diffraction analysis and Moessbauer effect studies have been done to determine the crystallographic structure and magnetic properties of 0.5Bi 0.95 Dy 0.05 FeO 3 -0.5Pb(Fe 2/3 W 1/3 )O 3 . T N temperature was estimated at around 600 K. (authors)

  2. Determination of the mean aerosol residence times in the atmosphere and additional 210Po input on the base of simultaneous determination of 7Be, 22Na, 210Pb, 210Bi and 210Po in urban air

    International Nuclear Information System (INIS)

    Magdalena Dlugosz-Lisiecka; Henryk Bem

    2012-01-01

    The significant differences in the activities of 210 Pb, 210 Bi, 210 Po and cosmogenic 7 Be and 22 Na radionuclides in the urban aerosol samples collected in the summers 2010 and 2011 in the Lodz city of Poland were observed. Simultaneous measurement of these radionuclides, after a simple modification of the one compartment model, allows us to calculate both: the corrected aerosol residence times in the troposphere (1 / 25 days) and in the lower stratosphere (103 / 205 days). The relative input of the additional sources (beside of the 222 Rn decay in the air) to the total activity concentrations of 210 Pb, 210 Bi and 210 Po radionuclides in the urban air, plays a substantial role (up to 97% of the total activity) only in the case of 210 Po. (author)

  3. Application of extended-crystal diffraction techniques to the symmetry and structure analysis of 221-PbBiSrCaCuO

    International Nuclear Information System (INIS)

    Goodman, P.; Miller, P.

    1993-01-01

    The discovery of a series of layer-perovskite superconducting compounds by Maeda et al. (1988) presented a challenge for present day electron diffraction techniques, due to their common occurrence as mixed phases, and the existence of complex structural modulations of more than one type. Cowley's (1976) theory developed specifically for describing diffraction effects from layered crystals having a micro-domainal sub-structure seems particularly well suited to the task of solving these structures, while the technique of extended-crystal diffraction is shown here to be capable of providing data of sufficient precision for this analysis. The present study is made on the 221 compound of PbBiSrCaCuO. Using the above diffraction techniques it is shown that the true symmetry of the whole structure is orthorhombic, Amaa, and not monoclinic as previously assumed, and that the superlattice reflections arise as a result of a basic microdomainal constitution, rather than from a uniform and incommensurate modulation. 8 figs

  4. The effect of Ag doping on superconducting properties of the Bi-Pb-Sr-Ca-Cu-O tape fabricated by an Ag sheath

    International Nuclear Information System (INIS)

    Oota, A.; Horio, T.; Ohba, K.; Iwasaki, K.

    1992-01-01

    The powder-in-tube method using an Ag sheath is applied to achieve high current capacity in the tapes of Bi-Pb-Sr-Ca-Cu-O (BPSCCO) with the high-T c phase (T c =110 K), by a combination process of cold working and sintering. Two kinds of the BPSCCO powder with and without Ag doping are used as the materials for tape fabrication. The morphology, structure, and critical current density J c are investigated on the tapes by x-ray diffraction, differential thermal analysis, scanning electron microscope, magnetic susceptibility, and I-V curves. The optimum sintering conditions to obtain a maximum in the value of J c at 77 K and 0 T are presented in the Ag-doped tapes and the nondoped ones. An improvement in the J c vs B properties up to 1 T at 77 K is presented in the BPSCCO tape by Ag doping. The Ag doping causes neither change in the value of T c (=110 K) nor decomposition of the high-T c phase

  5. A nonlinear analysis of the transport Barkhausen-like noise measured in (Bi,Pb)2Sr2Ca2Cu3O10+δ superconductors

    Science.gov (United States)

    García-Fornaris, I.; Millán, H.; Jardim, R. F.; Govea-Alcaide, E.

    2013-06-01

    We investigated the transport Barkhausen-like noise (TBN) by using nonlinear time series analysis. TBN signals were measured in (Bi,Pb)2Sr2Ca2Cu3O10+δ ceramic samples subjected to different uniaxial compacting pressures (UCP). These samples display similar intragranular properties but different intergranular features. We found positive Lyapunov exponents in all samples, λm≥0.062, indicating the nonlinear dynamics of the experimental TBN signals. It was also observed higher values of the embedding dimension, m >9, and the Kaplan-Yorke dimension, DKY>2.9. Between samples, the behavior of λm and DKY with increasing excitation current is quite different. Such a behavior is explained in terms of changes in the microstructure associated with the UCP. In addition, determinism tests indicated that the TBN masked determinist components, as inferred by |k →| values larger than 0.70 in most of the cases. Evidence on the existence of empirical attractors by reconstructing the phase spaces has been also found. All obtained results are useful indicators of the interplay between the uniaxial compacting pressure, differences in the microstructure of the samples, and the TBN signal dynamics.

  6. Absence of morphotropic phase boundary effects in BiFeO3-PbTiO3 thin films grown via a chemical multilayer deposition method

    Science.gov (United States)

    Gupta, Shashaank; Bhattacharjee, Shuvrajyoti; Pandey, Dhananjai; Bansal, Vipul; Bhargava, Suresh K.; Peng, Ju Lin; Garg, Ashish

    2011-07-01

    We report an unusual behavior observed in (BiFeO3)1- x -(PbTiO3) x (BF- xPT) thin films prepared using a multilayer chemical solution deposition method. Films of different compositions were grown by depositing several bilayers of BF and PT precursors of varying BF and PT layer thicknesses followed by heat treatment in air. X-ray diffraction showed that samples of all compositions show mixing of two compounds resulting in a single-phase mixture, also confirmed by transmission electron microscopy. In contrast to bulk compositions, samples show a monoclinic (MA-type) structure suggesting disappearance of the morphotropic phase boundary (MPB) at x=0.30 as observed in the bulk. This is accompanied by the lack of any enhancement of the remanent polarization at the MPB, as shown by the ferroelectric measurements. Magnetic measurements showed an increase in the magnetization of the samples with increasing BF content. Significant magnetization in the samples indicates melting of spin spirals in the BF- xPT films, arising from a random distribution of iron atoms. Absence of Fe2+ ions was corroborated by X-ray photoelectron spectroscopy measurements. The results illustrate that thin film processing methodology significantly changes the structural evolution, in contrast to predictions from the equilibrium phase diagram, besides modifying the functional characteristics of the BP- xPT system dramatically.

  7. Behavior of steels in flowing liquid PbBi eutectic alloy at 420-600 deg. C after 4000-7200 h

    International Nuclear Information System (INIS)

    Mueller, G.; Heinzel, A.; Konys, J.; Schumacher, G.; Weisenburger, A.; Zimmermann, F.; Engelko, V.; Rusanov, A.; Markov, V.

    2004-01-01

    This paper presents the results of steel exposure up to 7200 h in flowing LBE at elevated temperatures and is a follow-up paper of that with results of an exposure of up to 2000 h. The examined AISI 316 L, 1.4970 austenitic and MANET 10Cr martensitic steels are suitable as a structural material in LBE (liquid eutectic Pb 45 Bi 55 ) up to 550 deg. C, if 10 -6 wt% of oxygen is dissolved in the LBE. The martensitic steel develops a thick magnetite and spinel layer while the austenites have thin spinel surface layers at 420 deg. C and thick oxide scales like the martensitic steel at 550 deg. C. The oxide scales protect the steels from dissolution attack by LBE during the whole test period of 7200 h. Oxide scales that spall off are replaced by new protective ones. At 600 deg. C severe attack occurs already after 2000 and 4000 h of exposure. Steels with 8-15 wt% Al alloyed into the surface suffer no corrosion attack at all experimental temperatures and exposure times

  8. Charge retention characteristics of (Bi,La)4Ti3O12 capacitors : comparison with Pb(Zr,Ti)O3 capacitors

    International Nuclear Information System (INIS)

    Yoon, J. G.; Kim, D. J.; So, Y. W.

    2005-01-01

    We investigated the retention characteristics of (Bi,La) 4 Ti 3 O 12 (BLT) capacitors with Pt electrodes and compared them with Pb(Zr,Ti)O 3 (PZT) capacitors in the same- and opposite-state retentions. Polarization relaxations in short-time regime (t < 100 s) were well described by a power-law decay function, but the polarization relaxation of BLT was more significant than that of PZT. We discuss the difference in the relaxation process of polarization in conjunction with film microstructures and magnitudes of polarization for BLT and PZT. In long-time opposite-state retention, BLT capacitors showed much better characteristics than PZT. For both BLT and PZT, the opposite-state retention loss was governed by the development of an internal field during retention. For BLT capacitors, internal field development was much weaker than for PZT after retention, resulting in a good opposite-state retention. Structural and electrical properties are discussed in conjunction with the retention characteristics of the materials.

  9. Photoinduced changes in the fatigue behavior of SrBi2Ta2O9 and Pb(Zr,Ti)O3 thin films

    International Nuclear Information System (INIS)

    Dimos, D.; Al-Shareef, H.N.; Warren, W.L.; Tuttle, B.A.

    1996-01-01

    It is shown that SrBi 2 Ta 2 O 9 (SBT) thin films can be made to exhibit significant polarization fatigue by electric-field cycling under broad-band, optical illumination. Photoinduced fatigue is also observed for Pb(Zr,Ti)O 3 (PZT) thin-film capacitors with (La,Sr)CoO 3 (LSCO) electrodes. These results demonstrate that both the Pt/SBT/Pt and the LSCO/PZT/LSCO systems are susceptible to fatigue effects, which are attributed primarily to pinning of domain walls due to charge trapping. Capacitors that have been fatigued under illumination can be fully rejuvinated by applying a dc saturating bias with light or by electric-field cycling without light, which indicates an intrinsic, field-assisted recovery mechanism. We suggest that fatigue is essentially a competition between domain wall pinning and unpinning and that domain pinning is not necessarily absent in these nominally fatigue-free systems, but rather these systems are ones in which unpinning occurs at least as rapidly as any pinning. In both cases, the extent of photoinduced fatigue decreases with increased cycling voltage, indicating the relative importance of field-assisted unpinning. Finally, the observation of photoinduced fatigue implies that increased injection rates, potentially due to oxygen vacancy accumulation, may account for the electrode dependence on fatigue in PZT thin films

  10. Electromechanical properties of Na0.5Bi0.5TiO3-SrTiO3-PbTiO3 solid solutions

    Science.gov (United States)

    Svirskas, Šarūnas; Dunce, Marija; Birks, Eriks; Sternberg, Andris; Banys, Jūras

    2018-03-01

    Thorough studies of electric field-induced strain are presented in 0.4Na1/2Bi1/2TiO3-(0.6-x)SrTiO3-xPbTiO3 (NBT-ST-PT) ternary solid solutions. The increase of concentration of lead x induces crossover from relaxor to ferroelectric. Strain in a relaxor state can be described by electrostrictive behavior. The electrostrictive coefficients correspond to other well-known relaxor ferroelectrics. The concentration region with a stable ferroelectric phase revealed that the polarization dependence of strain does not exhibit nonlinearity, although they are inherent to the electric field dependence of strain. In this case, electric field dependence of strain is described in terms of the Rayleigh law and the role of domain wall contribution is extracted. Finally, the character of strain at the electric field-induced phase transition between the nonpolar and the ferroelectric states is studied. The data shows that in the vicinity of the electric field induced phase transition the strain vs. electric field displays electrostrictive character.

  11. Mn-Doped CaBi4Ti4O15/Pb(Zr,TiO3 Ultrasonic Transducers for Continuous Monitoring at Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Makiko Kobayashi

    2017-11-01

    Full Text Available Continuous ultrasonic in-situ monitoring for industrial applications is difficult owing to the high operating temperatures in industrial fields. It is expected that ultrasonic transducers consisting of a CaBi4Ti4O15(CBT/Pb(Zr,TiO3(PZT sol-gel composite could be one solution for ultrasonic nondestructive testing (NDT above 500 °C because no couplant is required and CBT has a high Curie temperature. To verify the high temperature durability, CBT/PZT sol-gel composite films were fabricated on titanium substrates by spray coating, and the CBT/PZT samples were tested in a furnace at various temperatures. Reflected echoes with a high signal-to-noise ratio were observed up to 600 °C. A thermal cycle test was conducted from room temperature to 600 °C, and no significant deterioration was found after the second thermal cycle. To investigate the long-term high-temperature durability, a CBT/PZT ultrasonic transducer was tested in the furnace at 600 °C for 36 h. Ultrasonic responses were recorded every 3 h, and the sensitivity and signal-to-noise ratio were stable throughout the experiment.

  12. Orbital angular momentum transfer and spin desalignment mechanisms in the deep inelastic collisions Ar+Bi and Ni+Pb using the sequential fission method

    International Nuclear Information System (INIS)

    Steckmeyer, J.C.

    1984-10-01

    Angular momentum transfer and spin dealignment mechanisms have been studied in the deep inelastic collisions Ar+Bi and Ni+Pb using the sequential fission method. This experimental technique consists to measure the angular distribution of the fission fragments of a heavy nucleus in coincidence with the reaction partner, and leads to a complete determination of the heavy nucleus spin distribution. High spin values are transferred to the heavy nucleus in the interaction and indicate that the dinuclear system has reached the rigid rotation limit. A theoretical model, taking into account the excitation of surface vibrations of the nuclei and the nucleon transfer between the two partners, is able to reproduce the high spin values measured in our experiments. The spin fluctuations are important, with values of the order of 15 to 20 h units. These fluctuations increase with the charge transfer from the projectile to the target and the total kinetic energy loss. The spin dealignment mechanisms act mainly in a plane approximately perpendicular to the heavy recoil direction in the laboratory system. These results are well described by a dynamical transport model based on the stochastic exchange of individual nucleons between the two nuclei during the interaction. The origin of the dealignment mechanisms in the spin transfer processes is then related to the statistical nature of the nucleon exchange. However other mechanisms can contribute to the spin dealignment as the surface vibrations, the nuclear deformations as well their relative orientations [fr

  13. Thermally activated dissipation and critical field Hc2 in c-oriented high-Tc Bi-Pb-Sr-Ca-Cu-O thin film

    International Nuclear Information System (INIS)

    Wang, Y.H.; Cui, C.G.; Zhang, Y.Z.; Li, S.L.; Li, J.; Li, L.

    1991-01-01

    A set of resistivity-temperature (R-T) curves measured under various applied fields in a high-T c Bi-Pb-Sr-Ca-Cu-O thin film which has a zero-resistance temperature T c0 of 110 K is reported. The remarkable broadening of the transition width is discussed under the flux-creep model, considering the very short coherence length of this oxide superconductor. The resistivity is thermally activated, which is consistent with the Arrhenius law with a magnetic field and orientation-dependent activation energy U 0 (H,Θ). The U 0 (H,Θ) has a very high value of 381.6 meV under a field of 0.1 T parallel to the c axis. The upper critical field H c2 determined from these R-T curves shows high values and the effect of flux creep to the H c2 (0) is examined by the irreversible behavior with the ''giant'' flux-creep model

  14. Ion mobility and conductivity in the M{sub 0.5–x}Pb{sub x}Bi{sub 0.5}F{sub 2+x} (M=K, Rb) solid solutions with fluorite structure

    Energy Technology Data Exchange (ETDEWEB)

    Kavun, V. Ya., E-mail: kavun@ich.dvo.ru [Institute of Chemistry FEBRAS, 159, Pr. 100-letya Vladivostoka, Vladivostok 690022 (Russian Federation); Uvarov, N.F. [Institute of Solid State Chemistry and Mechanochemistry, SB RAS, 18, Kutateladze Str., Novosibirsk 630128 (Russian Federation); Slobodyuk, A.B.; Polyantsev, M.M.; Merkulov, E.B. [Institute of Chemistry FEBRAS, 159, Pr. 100-letya Vladivostoka, Vladivostok 690022 (Russian Federation); Ulihin, A.S. [Institute of Solid State Chemistry and Mechanochemistry, SB RAS, 18, Kutateladze Str., Novosibirsk 630128 (Russian Federation); Goncharuk, V.K. [Institute of Chemistry FEBRAS, 159, Pr. 100-letya Vladivostoka, Vladivostok 690022 (Russian Federation)

    2017-05-15

    Ionic mobility and conductivity in the K{sub 0.5–x}Pb{sub x}Bi{sub 0.5}F{sub 2+x} and Rb{sub 0.5–x}Pb{sub x}Bi{sub 0.5}F{sub 2+x} (x=0.05, 0.09) solid solutions with the fluorite structure have been investigated using the methods of {sup 19}F NMR, X-ray diffraction and impedance spectroscopy. Types of ionic motions in the fluoride sublattice of solid solutions have been established and temperature ranges of their realization have been determined (150–450 K). Diffusion of fluoride ions is a dominating type of ionic motions in the fluoride sublattice of solid solutions under study above 350 K. Due to high ionic conductivity, above 10{sup –3} S/cm at 450 K, these solid solutions can be used as solid electrolytes in various electrochemical devices and systems. - Graphical abstract: Temperature dependence of the concentration of mobile (2, 4) and immobile (1, 3) F ions in the K{sub 0.5–x}Pb{sub x}Bi{sub 0.5}F{sub 2+x} solid solutions. - Highlights: • Studied the ion mobility, conductivity in M{sub 0.5–x}Pb{sub x}Bi{sub 0.5}F{sub 2+x} solid solutions (M=K, Rb). • An analysis of {sup 19}F NMR spectra made it possible to identify types of ion mobility. • The main type of ion motion above 300 K in solid solutions is a diffusion of ions F{sup –}. • The ionic conductivity of the solid solutions studied more than 10{sup –3} S/cm at 450 K.

  15. Thermal behavior of GeO{sub 2} doped PbO-B{sub 2}O{sub 3}-ZnO-Bi{sub 2}O{sub 3} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Yin [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Xiao Hanning [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)]. E-mail: hnxiao@hnu.cn; Guo Weiming [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Guo Wenming [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

    2006-05-15

    PbO-B{sub 2}O{sub 3}-ZnO-Bi{sub 2}O{sub 3} glass is a representative system for vacuum and electronic sealing. Effects of GeO{sub 2} on thermal properties of the glass have been investigated in this paper. Activation energy for crystallization, glass structure, the type of crystals were characterized by differential scanning calorimetry, infrared spectroscopy, X-ray diffraction and optical microscopy. Results indicate that the addition of GeO{sub 2} (0.4-2 wt.%) to PbO-B{sub 2}O{sub 3}-ZnO-Bi{sub 2}O{sub 3} glass can suppress crystallization of the glass and decrease the sealing temperature. With the increase of GeO{sub 2} content, germanate crystals were revealed, resulting in a slight increase of sealing temperature. When the content of GeO{sub 2} is 0.7 wt.%, the glass possesses the highest stability and lowest sealing temperature (400 deg. C), which is desirable for low-temperature sealing. The coefficient of thermal expansion of PbO-B{sub 2}O{sub 3}-ZnO-Bi{sub 2}O{sub 3} glass was measured by dilatometry. The result shows that the coefficient of thermal expansion of the glass increases with the content of GeO{sub 2}. The adjustability of the coefficient of thermal expansion would expand the applications of PbO-B{sub 2}O{sub 3}-ZnO-Bi{sub 2}O{sub 3} glass. A flexural strength of 28.3 MPa was obtained at the GeO{sub 2} content of 0.7 wt.%, showing good mechanical property for sealing process.

  16. Specific Effects of Oxygen Molecule and Plasma on Thin-Film Growth of Y-Ba-Cu-O and Bi-Sr-(Ca)-Cu-O Systems

    Science.gov (United States)

    Endo, Tamio; Horie, Munehiro; Hirate, Naoki; Itoh, Katsutoshi; Yamada, Satoshi; Tada, Masaki; Itoh, Ken-ichi; Sugiyama, Morihiro; Sano, Shinji; Watabe, Kinji

    1998-07-01

    Thin films of a-oriented YBa2Cu3Ox (YBCO), Ca-doped c-oriented Bi2(Sr,Ca)2CuOx and nondoped c-oriented Bi2Sr2CuOx (Bi2201) were prepared at low temperatures by ion beam sputtering with supply of oxygen molecules or plasma. The plasma enhances crystal growth of the a-YBCO and Ca-doped Bi2201 phases. This can be interpreted in terms of their higher surface energies. The growth and quality of nondoped Bi2201 are improved with the supply of oxygen molecules. This particular result could be interpreted by the collision process between the oxygen molecules and the sputtered particles.

  17. Z-contrast imaging of ordered structures in Pb(Mg1/3Nb2/3)O3 and Ba(Mg1/3Nb2/3)O3

    International Nuclear Information System (INIS)

    Yan, Y.; Pennycook, S.J.; Xu, Z.; Viehland, D.

    1998-02-01

    Lead-based cubic perovskites such as Pb(B 1/3 2+ B 2/3 5+ )O 3 (B 2+ Mg, Co, Ni, Zn; B 5+ = Nb, Ta) are relaxor ferroelectrics. Localized order and disorder often occur in materials of this type. In the Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) family, previous studies have proposed two models, space-charge and charge-balance models. In the first model, the ordered regions carry a net negative charge [Pb(Mg 1/2 Nb 1/2 )O 3 ], while in the second model it does not carry a net charge [Pb((Mg 2/3 Nb 1/3 ) 1/2 Nb 1/2 )O 3 ]. However, no direct evidence for these two models has appeared in the literature yet. In this paper the authors report the first direct observations of local ordering in undoped and La-doped Pb(Mg 1/3 Nb 2/3 )O 3 , using high-resolution Z-contrast imaging. Because the ordered structure in Ba(Mg 1/3 Nb 2/3 )O 3 is well known, the Z-contrast image from an ordered domain is used as a reference for this study

  18. Pb solubility of the high-temperature superconducting phase Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+d}

    Energy Technology Data Exchange (ETDEWEB)

    Kaesche, S.; Majewski, P.; Aldinger, F. [Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany)] [and others

    1994-12-31

    For the nominal composition of Bi{sub 2.27x}Pb{sub x}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+d} the lead content was varied from x=0.05 to 0.45. The compositions were examined between 830{degrees}C and 890{degrees}C which is supposed to be the temperature range over which the so-called 2223 phase (Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+d}) is stable. Only compositions between x=0.18 to 0.36 could be synthesized in a single phase state. For x>0.36 a lead containing phase with a stoichiometry of Pb{sub 4}(Sr,Ca){sub 5}CuO{sub d} is formed, for x<0.18 mainly Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+d} and cuprates are the equilibrium phases. The temperature range for the 2223 phase was found to be 830{degrees}C to 890{degrees}C but the 2223 phase has extremely varying cation ratios over this temperature range. Former single phase 2223 samples turn to multi phase samples when annealed at slightly higher or lower temperatures. A decrease in the Pb solubility with increasing temperature was found for the 2223 phase.

  19. Comparative study of gamma ray shielding and some properties of PbO–SiO2–Al2O3 and Bi2O3–SiO2–Al2O3 glass systems

    International Nuclear Information System (INIS)

    Singh, K.J.; Kaur, Sandeep; Kaundal, R.S.

    2014-01-01

    Gamma-ray shielding properties have been estimated in terms of mass attenuation coefficient, half value layer and mean free path values, whereas, structural studies have been performed in terms of density, optical band gap, glass transition temperature and longitudinal ultrasonic velocity parameters. X-ray diffraction, UV–visible, DSC and ultrasonic techniques have been used to explore the structural properties of PbO–SiO 2 –Al 2 O 3 and Bi 2 O 3 –SiO 2 –Al 2 O 3 glass systems. - Highlights: • Bi 2 O 3 –SiO 2 –Al 2 O 3 and PbO–SiO 2 –Al 2 O 3 glasses can replace conventional concretes as gamma-ray shielding materials. • Gamma-ray shielding properties improve with the addition of heavy metals. • Rigidity deteriorates with the increase in the content of heavy metals. • Bi 2 O 3 –SiO 2 –Al 2 O 3 glass system is better than PbO–SiO 2 –Al 2 O 3 glass system in terms of gamma-ray shielding as well as structural properties

  20. Enhanced piezoelectricity in (1 -x)Bi1.05Fe1-yAyO3-xBaTiO3 lead-free ceramics: site engineering and wide phase boundary region.

    Science.gov (United States)

    Zheng, Ting; Jiang, Zhenggen; Wu, Jiagang

    2016-07-28

    Site engineering has been employed to modulate the piezoelectric activity of high temperature (1 -x)Bi1.05Fe1-yScyO3-xBaTiO3 lead-free ceramics fabricated by a conventional solid-state method together with a quenching technique. The effects of x and y content on the phase structure, microstructure, and electrical properties have been investigated in detail. A wide rhombohedral (R) to pseudo-cubic (C) phase boundary was formed in the ceramics with x = 0.30 and 0 ≤y≤ 0.07, thus leading to enhanced piezoelectricity (d33 = 120-180 pC N(-1)), ferroelectricity (Pr = 19-22 μC cm(-2)) and a high Curie temperature (TC = 478-520 °C). In addition, the influence of different element substitutions for Fe(3+) on phase structure and electrical behavior was also investigated. Improved piezoelectricity (d33 = 160-180 pC N(-1)) and saturated P-E loops can be simultaneously achieved in the ceramics with A = Sc, Ga, and Al due to the R-C phase boundary. As a result, site engineering may be an efficient way to modulate the piezoelectricity of BiFeO3-BaTiO3 lead-free ceramics.

  1. Effect of doping of vanadium ions on crystal structure, dielectric and magnetic properties of Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3} multiferroic

    Energy Technology Data Exchange (ETDEWEB)

    Godara, Priyanka; Agarwal, Ashish; Ahlawat, Neetu; Sanghi, Sujata, E-mail: sutkash@yahoo.com; Kaswan, Kavita

    2016-05-15

    Synthesis of Bi{sub 0.8}Ba{sub 0.2}Fe{sub 1−x}V{sub x}O{sub 3} multiferroics (with x=0.0, 0.02 and 0.04 having code V0, V2 and V4, respectively) have been done by solid-state reaction technique. The structural, magnetic and electrical characterization of the prepared ceramics have been carried out using X-ray diffraction, Vibrating sample magnetometry and impedance spectroscopy, respectively. Rietveld refinement studies show that all samples have rhombohedral structure (R3c). The observed lattice distortion is due to the difference in the ionic radii of parent ions and doped ions. Sizeable M–H hysteresis loops revealed the transformation of antiferromagnetic BiFeO{sub 3} (BFO) into ferromagnetic with Ba and V addition. The highest values of coercive field ~4.5 kOe and saturation magnetization ~1.14 emu/g are observed for V0 and V2 samples, respectively. The dielectric properties were improved with the co-doping as compared with the pure BFO compound due to structural distortion and decrease of oxygen vacancies by addition of higher valence V{sup 5+} cation. - Highlights: • Refinement has been done by hexagonal representation of R3c space group. • Magnetic properties are affected by the distortion in Fe–O octahedral. • Dielectric properties have improved on co-doping.

  2. Sol–gel preparation of well-adhered films and long range ordered inverse opal films of BaTiO{sub 3} and Bi{sub 2}Ti{sub 2}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Al-Arjan, Wafa S. [Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); King Faisal University, PO Box 380, Al Hofuf (Saudi Arabia); Algaradah, Mohammed M.F. [Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); King Khalid College, Riyadh (Saudi Arabia); Brewer, Jack [Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Hector, Andrew L., E-mail: a.l.hector@soton.ac.uk [Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom)

    2016-02-15

    Highlights: • Highly adaptable sols are presented for processing of the electroceramic materials BaTiO{sub 3} and Bi{sub 2}Ti{sub 2}O{sub 7}. • High quality thin films are produced by dip coating with good phase control. • Infiltration of cross-linked polystyrene templates led to high quality inverse opals. - Abstract: Barium and bismuth titanate thin films and well-ordered inverse opal films are produced by dip coating from sols containing titanium alkoxides with acetic acid, acetylacetone, methoxyethanol and water. The inverse opal preparations used crosslinked polystyrene opal templates. Heat treatment in air produced tetragonal BaTiO{sub 3} or mixtures of the hexagonal and tetragonal phases, or phase pure Bi{sub 2}Ti{sub 2}O{sub 7}. Good quality films were obtained with a thickness of 5 μm from a single dipping, and the thickness could be increased by dipping multiple times. Inverse opals were well ordered and exhibited opalescence and photonic stop band effects.

  3. Raman scattering, microstructural and dielectric studies on Ba{sub 1-x}Ca{sub x}Bi{sub 4}Ti{sub 4}O{sub 15} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sunil; Kundu, Swarup [Materials Research Centre, Indian Institute of Science, Bangalore 560012 (India); Ochoa, D.A.; Garcia, J.E. [Department of Applied Physics, Universitat Politecnica de Catalunya, 08034 Barcelona (Spain); Varma, K.B.R., E-mail: kbrvarma@mrc.iisc.ernet.in [Materials Research Centre, Indian Institute of Science, Bangalore 560012 (India)

    2012-10-15

    Polycrystalline powders of Ba{sub 1-x}Ca{sub x}Bi{sub 4}Ti{sub 4}O{sub 15} (where x = 0, 0.25, 0.50, 0.75 and 1) were prepared via the conventional solid-state reaction route. X-ray diffraction (XRD) and Raman scattering techniques have been employed to probe into the structural changes on changing x. XRD analyses confirmed the formation of monophasic bismuth layered structure of all the above compositions with an increase in orthorhombic distortion with increase in x. Raman spectra revealed a redshift in A{sub 1g} peak and an increase in the B{sub 2g}/B{sub 3g} splitting with increasing Ca content. The average grain size was found to increase with increasing x. The temperature of the maximum dielectric constant (T{sub m}) increased linearly with increasing Ca-content whereas the diffuseness of the phase transition was found to decrease with the end member CaBi{sub 4}Ti{sub 4}O{sub 15} showing a frequency independent sharp phase transition around 1048 K. Ca doping resulted in a decrease in the remnant polarization and an increase in the coercive field. Ba{sub 0.75}Ca{sub 0.25}Bi{sub 4}Ti{sub 4}O{sub 15} ceramics showed an enhanced piezoelectric coefficient d{sub 33} of 15 pC N{sup -1} at room temperature. Low values of dielectric losses and tunability of temperature coefficient of dielectric constant ({tau}{sub {epsilon}}) in the present solid-solution suggest that these compounds can be of potential use in microwave dielectrics at high temperatures. Highlights: Black-Right-Pointing-Pointer Ba{sub 1-x}Ca{sub x}Bi{sub 4}Ti{sub 4}O{sub 15} (0 {<=} x {<=} 1) ceramics with four-layer Aurivillius structure were fabricated. Black-Right-Pointing-Pointer X-ray diffraction and Raman scattering techniques have been employed to probe into the structural changes on changing x. Black-Right-Pointing-Pointer Curie temperature (T{sub C}) was found to increase with increase in Ca-doping whereas the diffuseness of phase transition decreased. Black-Right-Pointing-Pointer Temperature

  4. Zoneamento agroecológico do município de Lagoa Seca, PB Agroecological zoning of the municipal district of Lagoa Seca, Paraíba State

    Directory of Open Access Journals (Sweden)

    Íris do S. Barbosa

    2009-10-01

    Full Text Available Visa-se, cinzelar, neste estudo um zoneamento em que se considerem os aspectos agrícolas, ecológicos e sociais inerentes ao município de Lagoa Seca, PB, elaborado através da análise dos vários cenários apresentados na área. O uso de um conjunto de recursos, como fotointerpretação, processamento de imagens georreferenciadas, posicionamento por satélites, associados à teoria sistêmica de Bertrand, possibilitou a identificação, delimitação e análise das áreas de uso antrópico, agrícola e das áreas com remanescentes vegetais significativos, que caracterizam o município. Foram elaborados para a área em estudo, arquivos digitais georreferenciados, relativos aos temas: limite municipal, áreas urbanizadas, infra-estrutura viária, rede de drenagem, altimetria, cobertura vegetal natural, uso agrícola do solo e zoneamento. Os resultados obtidos evidenciaram que o município apresenta quatro regiões com aspectos distintos, as quais foram identificadas como regiões agroecológicas, de acordo com o fator que mais se destacou em cada área.This work sought to perfect zoning which concerns the agricultural, ecological and social aspects in the municipality of Lagoa Seca in the State of Paraíba through the study of several scenarios in that area. It consisted of a set of approaches such as photo interpretation, geo-referenced image processing, and satellite positioning associated with Bertrand's Systemic Theory that allowed the identification, delimitation and analysis of areas of anthropic and agricultural usage as well as of those with remaining significant vegetation, which characterize the municipality. Digital geo-referenced files were elaborated for the studied area comprising basic data about the municipal limit, urbanized areas, road systems, drainage system, altimetry, cover of natural vegetation, soil farming usage and zoning of agroecological regions. The study showed that the municipality of Lagoa Seca has four regions

  5. Structural and luminescence studies of Eu3+: TeO2sbnd B2O3sbnd AOsbnd AF2 (A = Pb, Ba, Zn, Cd, Sr) glasses

    Science.gov (United States)

    Selvi, S.; Marimuthu, K.; Muralidharan, G.

    2017-09-01

    Eu3+ doped oxyfluoro boro-tellurite (TBXFE) with molar composition 29 TeO2sbnd 30B2O3sbnd 20AOsbnd 20AF2sbnd 1Eu2O3 (where A = Pb, Ba, Zn, Cd, Sr) glasses were prepared and investigated by XRD, FTIR, UV-Vis-NIR, luminescence and decay measurements. XRD patterns confirm the glassy nature of the prepared glasses. The influence of metal ions on the structure of boro-tellurite glasses were investigated through FTIR spectra. The intra band (4f-4f) transitions of Eu3+ ions are discussed through UV-Vis-NIR absorption spectra. The covalent nature around the Eu3+ ions with ligands are discussed using the bonding parameter (δ) and nephelauxetic ratio (β). The fundamental absorption edge, direct, indirect band gap, Urbach energy and band tailing parameters are reported. A bright red emission at 616 nm corresponding to the 5D0 → 7F2 transition of Eu3+ ions could be observed in the title glasses. Judd-Ofelt parameters were estimated from the emission spectra of Eu3+ ions. The dependence of these parameters on the composition of the glass is discussed. Judd-Ofelt parameters were used to derive the radiative parameters such as transition probabilities (A, s-1), branching ratios (βR), radiative lifetime (τrad) and stimulated emission cross-section (σPE) for the 5D0 → 7FJ (J = 0, 1, 2, 3 and 4) transitions. The luminescence intensity ratio (LIR) of 5D0 → 7F2/5D0 → 7F1 transitions was estimated to analyze the local site symmetry around the Eu3+ ions in the present glasses. The chromaticity coordinates and colour purity were calculated from the emission spectra and analyzed with Commission International de I'Eclairage (CIE) 1931 diagram. The experimental lifetime of 5D0 level could be fitted to a single exponential indicating the absence of energy transfer between the Eu3+ ions in the present glasses.

  6. Phase stability study of Bi0.15Sr0.85-xAexCoO3-δ (x = 0 and Ae = Ba0.28; Ca0.17) perovskites by in-situ neutron diffraction

    International Nuclear Information System (INIS)

    Eriksson, A.K.; Eriksson, S.G.; Chapon, L.C.; Knee, C.S.

    2010-01-01

    The oxygen deficient perovskites, Bi 0.15 Sr 0.85-x Ae x CoO 3-δ , x = 0 and Ae x = Ba 0.28 , Ca 0.17 , were studied with in-situ neutron powder diffraction and combined TGA/DSC in order to investigate their behaviour at elevated temperatures in oxidising conditions. The phase stability of the I4/mmm supercell structure adopted by Bi 0.15 Sr 0.85 CoO 3-δ is shown to be dependent on temperature and the oxygen content of the phase, with three structural events, at T ∼ 250, 590 and 880 o C, detected. The first transition occurs as the perovskite supercell vanishes due to oxygen absorption; the second transition is also associated with oxidation and involves the decomposition of the perovskite phase via an exothermic process to yield a dominant hexagonal phase. Finally, at T ∼ 900 o C the perovskite phase re-forms. For the Ba and Ca containing materials the decomposition to the hexagonal phase occurs at T ∼ 600 o C and ∼ 650 o C respectively. The presence of Ca at the A-site is found to stabilise the I4/mmm supercell structure in the range RT - 650 o C. The antiferromagnetic to paramagnetic transitions occur at T N ∼ 250 o C, T N ∼ 175 o C and T N ∼ 145 o C for the samples with Ae x = Ba 0.28 , x = 0 and Ae x = Ca 0.17 , respectively.

  7. Determination of 210Pb by direct gamma-ray spectrometry, beta counting via 210Bi and alpha-particle spectrometry via 210Po in coal, slag and ash samples from thermal power plant

    International Nuclear Information System (INIS)

    Seslak, Bojan; Vukanac, Ivana; Kandic, Aleksandar; Durasevic, Mirjana; Eric, Milic; Jevremovic, Aleksandar

    2017-01-01

    In order to compare three different techniques and estimate radiological impact, activity concentration of 210 Pb in coal, slag and ash samples from thermal power plant 'Nikola Tesla', Serbia, were measured, and results are presented in this study. Determination of 210 Pb was carried out in three ways: using HPGe gamma spectrometer and via in-growth of 210 Po and 210 Bi by alpha-particle spectrometry and proportional counting, respectively. The results obtained for three different techniques were compared. Statistical analysis and comparison of methods were carried out by combination of Z score and χ 2 statistical tests. Tests results, as well as values of measured activities concentrations obtained by alpha and gamma spectrometry, showed that gamma spectrometry is a valid alternative to time-consuming alpha spectrometry for low level activity measurements of 210 Pb. This remark is also valid even for gamma spectrometers with poor efficiency in low energy region. (author)

  8. Crystal structure and magnetic properties of Bi0.8A0.2FeO3 (A = La, Ca, Sr, Ba multiferroics using neutron diffraction and Mossbauer spectroscopy

    Directory of Open Access Journals (Sweden)

    Manisha Rangi

    2014-08-01

    Full Text Available Bi0.8A0.2FeO3 (A = La, Ca, Sr, Ba multiferroics were studied using x-ray, neutron diffraction and magnetization techniques. All the samples crystallized in rhombohedral structure with space group R3c. The compounds exhibit antiferromagnetic (AFM ordering at 300 K and no evidence of further structural or magnetic transition was observed on lowering of temperature below it. The magnetic structure of these substituted compounds are found to be collinear G-type AFM structure as against the non collinear incommensurate magnetic structure reported in the case of parent compound. The moments on Fe at 6 K are aligned along the a-axis in the case of Ca-doped sample. With increase in the ionic radii of dopant, the moments are found to be aligned in the ac plane and the angle of tilt away from the a-axis increases. The observed change in the magnetic structure with substitution is attributed to the intrinsic structural distortion as evidenced by the change in the bond angle (Fe-O-Fe and bond distances (Bi-O, Fe-O. It has been found that heterovalent substitution A2+ results in the formation of oxygen vacancies in the parent lattices as the possibility of Fe4+ ruled out by Mössbauer spectra recorded at room temperature. Higher value of remnant magnetization (0.4187 emu/g and coercivity (4.7554kOe is observed in Bi0.8Ba0.2FeO3 sample in comparison to other substituted samples revealing a strong correlation between ionic radii and magnetization.

  9. A comparative study on the magnetic and electrical properties of MFe{sub 12}O{sub 19} (M=Ba and Sr)/BiFeO{sub 3} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, M.A., E-mail: moala47@hotmail.com [Materials Science Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt); Mansour, S.F. [Physics Department, Faculty of Science, Zagazig University (Egypt); Ismael, H. [Materials Science Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt)

    2015-03-15

    M-type hexaferrite (MFe{sub 12}O{sub 19}), M=Ba or Sr nanoparticles with hexagonal crystal structure have been successfully synthesized by a citrate auto-combustion method. BiFeO{sub 3} (BFO) was prepared by the flash auto-combustion technique. Different nanocomposites were prepared according to the formula [(1−X) MFe{sub 12}O{sub 19}+XBiFeO{sub 3}; M=Ba or Sr, X=0.3, 0.4, 0.5 and 0.6]. The structure and morphology of the obtained nanocomposites have been determined by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). From the results, it is observed that the value of saturation magnetization decreases with increasing BFO content, which was mainly due to the contribution of the volume of the weak-magnetic BFO to the total sample volume. - Highlights: • M-type nanohexaferrite (MFe{sub 12}O{sub 19}) as M=Ba and Sr powders were synthesized by the citrate autocombustion method. • The lattice parameters of composite were negligibly smaller than those of M-type. • FESEM showed that the samples were hexagonal plate-like shape. • M{sub s}, M{sub r}, μ{sub eff.} and H{sub C} were improved to be suitable for perpendicular high density recording media. • ε′ increased with BFO ratio which is useful in microwave devices.

  10. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K0.5Bi0.5TiO3-BaTiO3-Na0.5Bi0.5TiO3 piezoelectric materials.

    Science.gov (United States)

    Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

    2015-02-26

    We synthesized grain-oriented lead-free piezoelectric materials in (K0.5Bi0.5TiO3-BaTiO3-xNa0.5Bi0.5TiO3 (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d33 ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials.

  11. First results on T91 claddings with and without modified FeCrAlY coatings exposed in PbBi under varying conditions

    International Nuclear Information System (INIS)

    Weisenburger, A.; Heinzel, A.; Miller, G.; Rousanov, A.

    2008-01-01

    It is well known that at temperatures above 500 deg C low activation austenitic steels suffer from severe corrosion in lead or lead-bismuth. Low activation martensitic steels instead form under similar conditions concerning temperature and oxygen content thick oxide scales that periodically may span off. Both groups of materials are therefore restricted to areas having lower temperature load. For parts that are intended to be used in high-temperature regions, like claddings, surface protection has to be applied. From gas turbines the role of elements forming thin stable oxide scales is well understood. The concept chosen here for thermally high loaded parts, the claddings, is the deposition of a FeCrAlY coating of about 30 vt,m thickness that is afterwards re-melted applying a pulsed electron beam (GESA). The beam energy is adjusted in a way to melt the entire coating together with a few thin region of the bulk to create a perfect intermixing at the boundary. This results in a new surface area of the cladding with an aluminium content of the order of 5 wt.% that will be sufficiently high to grow thin stable oxide scales. This concept is proven for austenitic cladding materials like 1.4970 as well as for martensitic ones like T91. In long-term corrosion tests the compatibility to Pb or PbBi, the resistance against corrosion and severe oxidation, was clearly demonstrated. No negative response of such a modified coating on the mechanical properties and the stability under irradiation has been observed as of yet. This paper will focus on the surface modification process, the corrosion results thus far obtained and on the evaluation of some mechanical properties. For example, the swelling of the fuel by irradiation will lead during operation to an increase of the internal pressure. This is simulated in experiments where an internal pressure of defined value was applied on T91 cladding tubes. The influence of flow velocity between to 3 m/s on the oxidation behaviour of T

  12. Simultaneous achievement of high dielectric constant and low temperature dependence of capacitance in (111-oriented BaTiO3-Bi(Mg0.5Ti0.5O3-BiFeO3 solid solution thin films

    Directory of Open Access Journals (Sweden)

    Junichi Kimura

    2016-01-01

    Full Text Available The temperature dependence of the capacitance of (111c-oriented (0.90–xBaTiO3-0.10Bi(Mg0.5Ti0.5O3-xBiFeO3 solid solution films is investigated. These films are prepared on (111cSrRuO3/(111Pt/TiO2/SiO2/(100Si substrates by the chemical solution deposition technique. All the films have perovskite structures and the crystal symmetry at room temperature varies with increasing x ratio, from pseudocubic when x = 0–0.30 to rhombohedral when x = 0.50–0.90. The pseudocubic phase shows a high relative dielectric constant (εr (ranging between 400 and 560 at room temperature and an operating frequency of 100 kHz and a low temperature dependence of capacitance up to 400°C, while maintaining a dielectric loss (tan δ value of less than 0.2 at 100 kHz. In contrast, εr for the rhombohedral phase increases monotonically with increasing temperature up to 250°C, and increasingly high tan δ values are recorded at higher temperatures. These results indicate that pseudocubic (0.90–xBaTiO3-0.10Bi(Mg0.5Ti0.5O3-xBiFeO3 solid solution films with (111 orientation are suitable candidates for high-temperature capacitor applications.

  13. Transport properties of Pb-doped Bi4Sr3Ca3Cu4Ox semiconducting glasses and glass-ceramic superconductors

    International Nuclear Information System (INIS)

    Chatterjee, S.; Banerjee, S.; Mollah, S.; Chaudhuri, B.K.

    1996-01-01

    Electrical conductivity and thermoelectric power (TEP) of the as-quenched and annealed (at 500 degree C for 10 h and 840 degree C for 24 h) Bi 4-n Pb n Sr 3 Ca 3 Cu 4 O x (x = 0 endash 1.0) glasses have been measured. The dc conductivity data of the as-quenched and the partially annealed (at 500 degree C) glasses can be explained by considering the small-polaron hopping conduction mechanism which is found to change from the nonadiabatic to the adiabatic regime with annealing the glasses at 500 degree C. This change over is due to the presence of microcrystals in the partially annealed glasses as observed from x-ray-diffraction and scanning electron microscopic studies. This adiabatic behavior is also visualized even for some as-quenched glasses having a very small amount of the more conducting microcrystalline phase. All the 840 degree C annealed glasses are superconductors with T c between 110 and 115 K. The Seebeck coefficient (S) of the partially annealed glass system is found to be positive and increases linearly with temperature. The S values of the corresponding glass-ceramic superconductors showing broad peaks around T c . A change over in the values of S from positive (below ∼290 K) to negative (above ∼290 K) indicates the coexistence of both electrons and holes in these superconductors. The TEP data can be fitted with both the two-band model of Forro et al. [Solid State Commun. 73, 501 (1990)] and the Nagaosa-Lee model [Phys. Rev. Lett. 64, 2450 (1990)]. Therefore, the bosonic contribution in the transport properties of these superconductors, as suggested by the Nagaosa-Lee model, is supported. copyright 1996 The American Physical Society

  14. Investigating the effect of multiple grain–grain interfaces on electric and magnetic properties of [50 wt% BaFe{sub 12}O{sub 19}–50 wt% Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}] composite system

    Energy Technology Data Exchange (ETDEWEB)

    Pattanayak, Ranjit, E-mail: ranjit.p20@gmail.com [Department of Physics and Astronomy, National Institute of Technology, Rourkela 769008 (India); Muduli, Rakesh; Panda, Ranjit Kumar [Department of Physics and Astronomy, National Institute of Technology, Rourkela 769008 (India); Dash, Tapan [CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, Odisha (India); Sahu, Priyanka; Raut, Subhajit; Panigrahi, Simanchala [Department of Physics and Astronomy, National Institute of Technology, Rourkela 769008 (India)

    2016-03-15

    This report presents the fabrication, electrical properties along with the magnetic parameters of a composite system considering a strong ferrimagnetic (BaFe{sub 12}O{sub 19}) and a ferroelectric (Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}) material. Polycrystalline 50 wt% BaFe{sub 12}O{sub 19} (BaM)–50 wt% Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} (NBT) composite system was prepared by the solid state reaction method. Rietveld refinement of XRD pattern confirms the presence of BaM and NBT phases without any impurity phase. From scanning electron micrograph both the phases are also clearly identified. In this report, the electric relaxation and conductivity properties were systematically investigated and analyzed in the frequency range of 100 Hz to 1 MHz and temperature range of 30–200 °C. The presence of different type of grains and significant reduction in the resistance of the composite system were found to be responsible for the nature of electric relaxation behavior. A peculiar and interesting evolution of grain boundary conduction was detected which was argued due to the existence of three possible grain boundaries such as: (i) BaM–BaM interface, (ii) NBT–NBT interface and (iii) BaM–NBT interface. The magnetization study (M–H loop) paves that, the saturation magnetization and coercive field reduces for composite system.

  15. Investigation of radiation shielding properties for MeO-PbCl2-TeO2 (MeO = Bi2O3, MoO3, Sb2O3, WO3, ZnO) glasses

    Science.gov (United States)

    Sayyed, M. I.; Çelikbilek Ersundu, M.; Ersundu, A. E.; Lakshminarayana, G.; Kostka, P.

    2018-03-01

    In this work, glasses in the MeO-PbCl2-TeO2 (MeO = Bi2O3, MoO3, Sb2O3, WO3, ZnO) system, which show a great potential for optoelectronic applications, were used to evaluate their resistance under high energy ionizing radiations. The basic shielding quantities for determining the penetration of radiation in glass, such as mass attenuation coefficient (μ/ρ), half value layer (HVL), mean free path (MFP) and exposure buildup factor (EBF) values were investigated within the energy range 0.015 MeV ‒ 15 MeV using XCOM program and variation of shielding parameters were compared with different glass systems and ordinary concrete. From the derived results, it was determined that MeO-PbCl2-TeO2 (MeO = Bi2O3, MoO3, Sb2O3, WO3, ZnO) glasses show great potentiality to be used under high energy radiations. Among the studied glass compositions, Bi2O3 and WO3 containing glasses were found to possess superior gamma-ray shielding effectiveness.

  16. Evaluation of matrix effect on the determination of rare earth elements and As, Bi, Cd, Pb, Se and In in honey and pollen of native Brazilian bees (Tetragonisca angustula - Jataí) by Q-ICP-MS.

    Science.gov (United States)

    de Oliveira, Fernanda Ataide; de Abreu, Adriana Trópia; de Oliveira Nascimento, Nathália; Froes-Silva, Roberta Eliane Santos; Antonini, Yasmine; Nalini, Hermínio Arias; de Lena, Jorge Carvalho

    2017-01-01

    Bees are considered the main pollinators in natural and agricultural environments. Chemical elements from honey and pollen have been used for monitoring the environment, the health of bees and the quality of their products. Nevertheless, there are not many studies on honey and pollen of native Brazilian bees. The goal of this work was to determine important chemical elements (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Lu and Yb) along with As, Bi, Cd, Pb, Se and In, in honey and pollen of native Brazilian bees, assessing analytical interferences from the matrix. A proposed analytical method was developed for these elements by quadrupole ICP-MS. Matrix effect was verified in honey matrix in the quantification of As, Bi and Dy; and in pollen matrix for Bi, Cd, Ce, Gd, La, Pb and Sc. The quality of the method was considered satisfactory taking into consideration the recovery rate of each element in the spiked solutions: honey matrix (91.6-103.9%) and pollen matrix (94.1-115.6%). The quantification limits of the method ranged between 0.00041 and 10.3μgL -1 for honey and 0.00041-0.095μgL -1 for pollen. The results demonstrate that the method is accurate, precise and suitable. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Multilevel Resistance Switching Memory in La2/3Ba1/3MnO3/0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (011) Heterostructure by Combined Straintronics-Spintronics.

    Science.gov (United States)

    Zhou, Weiping; Xiong, Yuanqiang; Zhang, Zhengming; Wang, Dunhui; Tan, Weishi; Cao, Qingqi; Qian, Zhenghong; Du, Youwei

    2016-03-02

    We demonstrate a memory device with multifield switchable multilevel states at room temperature based on the integration of straintronics and spintronics in a La2/3Ba1/3MnO3/0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) (011) heterostructure. By precisely controlling the electric field applied on the PMN-PT substrate, multiple nonvolatile resistance states can be generated in La2/3Ba1/3MnO3 films, which can be ascribed to the strain-modulated metal-insulator transition and phase separation of Manganite. Furthermore, because of the strong coupling between spin and charge degrees of freedom, the resistance of the La2/3Ba1/3MnO3 film can be readily modulated by magnetic field over a broad temperature range. Therefore, by combining electroresistance and magnetoresistance effects, multilevel resistance states with excellent retention and endurance properties can be achieved at room temperature with the coactions of electric and magnetic fields. The incorporation of ferroelastic strain and magnetic and resistive properties in memory cells suggests a promising approach for multistate, high-density, and low-power consumption electronic memory devices.

  18. Structural, dielectric and magnetic properties of Bi{sub 0.8}Ba{sub 0.2}Fe{sub 0.6}Mn{sub 0.4}O{sub 3} ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Rangi, Manisha, E-mail: mrangi100@gmail.com; Sanghi, S.; Agarwal, A.; Kaswan, K.; Jangra, S.; Singh, O. [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana (India)

    2016-05-23

    Polycrystalline Bi{sub 0.8}Ba{sub 0.2}Fe{sub 0.6}Mn{sub 0.4}O{sub 3} ceramic was synthesized via conventional two stage solid state reaction method. The crystal structure is examined via powder x-ray diffraction and Rietveld refinement revealed that the sample has a rhombohedral crystal structure (space group R3c). The dielectric response of the sample was analyzed in the frequency range 10 Hz to 5 MHz at different temperature. The values of dielectric constant (ε′) and dielectric loss factor (tan δ) increases with increasing temperature at different frequencies which may be the result of increase in the number of charge carriers and their mobilities due to the thermal activation. M-H hysteresis loop was recorded at room temperature up to a field of 15 kOe which shows that there is slightly enhancement in magnetization with co-doping.

  19. Optical, ferroelectric and magnetic properties of multiferroelectric BiFeO3-(K0.5Na0.5)0.4(Sr 0.6Ba0.4)0.8Nb2O6 thin films

    KAUST Repository

    Yao, Yingbang

    2014-02-01

    Multiferroic BiFeO3-(K0.5Na0.5) 0.4(Sr0.6Ba0.4)0.8Nb 2O6 (BFO-KNSBN) trilayer thin films, were epitaxially grown on MgO(0 0 1) and SrTiO3(0 0 1) by using pulsed laser deposition (PLD). Their ferroelectric, magnetic, dielectric and optical properties were investigated. It was found that both ferroelectric polarization and dielectric constant of the films were enhanced by introducing KNSBN as a barrier layer. Meanwhile, ferromagnetism of BFO was maintained. More interestingly, a double hysteresis magnetic loop was observed in the KNSBN-BFO-KNSBN trilayer films, where exchange bias and secondary phase in the BFO layer played crucial roles. Interactions between adjacent layers were revealed by temperature-dependent Raman spectroscopic measurements. © 2013 Elsevier B.V. All rights reserved.

  20. Effects of thermal and electrical histories on structure and dielectric behaviors of (Li0.5Nd0.52+-modified (Bi0.5Na0.5TiO3-BaTiO3 ceramics

    Directory of Open Access Journals (Sweden)

    Jiwen Xu

    2017-06-01

    Full Text Available The effect of thermal and electrical histories on structure and dielectric behaviors is studied using 0.95(Bi0.5Na0.50.97(Li0.5Nd0.50.03TiO3-0.05BaTiO3 (abbreviated as BNTLN0.03-BT5 ceramic as a selected system. Subtle structure change caused by annealing treatment, and pronounced phase transition and domain switching by electrical poling, are observed to occur, respectively. The dielectric constant and its strong frequency dispersion in unpoled samples decrease evidently by electrical poling due to electric field-induced ordered domain. The high temperature Maxwell-Wagner relaxor behavior vanishes by annealing treatment due to the loss of electrical inhomogeneity with interface charging effects. Piezoelectric properties are improved evidently by annealing treatment at 900 °C, implying a new appropriate method to improve piezoelectric properties.

  1. Crystal Growth and Characterization of (Bi0.5Na0.5)TiO3-BaTiO3 Single Crystals Obtained by a Top-Seeded Solution Growth Method under High-Pressure Oxygen Atmosphere

    Science.gov (United States)

    Onozuka, Hiroaki; Kitanaka, Yuuki; Noguchi, Yuji; Miyayama, Masaru

    2011-09-01

    A single crystal of ferroelectric 0.88(Bi,Na)TiO3-0.12BaTiO3 (BNT-BT) solid solution with tetragonal P4mm structure was grown by a top-seeded solution growth (TSSG) method at a high oxygen pressure (PO2 ) of 0.9 MPa. The crystals exhibited a large remanent polarization (Pr) of 54 µC/cm2, which leads to a spontaneous polarization estimated to be 54 µC/cm2. The large Pr compared with that of crystals grown at PO2 = 0.1 MPa is suggested to originate from a low oxygen vacancy concentration. The high-PO2 TSSG method is demonstrated to be effective for obtaining large-sized, high-quality BNT-BT crystals.

  2. Type-I pseudo-first-order phase transition induced electrocaloric effect in lead-free Bi0.5Na0.5TiO3-0.06BaTiO3 ceramics

    Science.gov (United States)

    Li, Feng; Chen, Guorui; Liu, Xing; Zhai, Jiwei; Shen, Bo; Li, Shandong; Li, Peng; Yang, Ke; Zeng, Huarong; Yan, Haixue

    2017-05-01

    In this study, the electrocaloric effect (ECE) of Bi0.5Na0.5TiO3-0.06BaTiO3 (BNT-0.06BT) ceramic has been directly measured using a home-made adiabatic calorimeter. The maximum adiabatic temperature change (ΔT) approaches 0.86 K under an electric field of 5 kV/mm at 110 °C, which provides experimental evidence for optimizing the ECE near the type-I pseudo-first-order phase transition (PFOPT). Most importantly, a considerable ΔT value can be maintained over a wide temperature range well above the temperature of the PFOPT under a high electric field. In addition, ΔT is closely related to the structural transition and electric field strength. This work provides a guideline to investigate the high ECE in BNT-based ferroelectric ceramics for applications in cooling technologies.

  3. Temperature dependent polarization reversal mechanism in 0.94(Bi1/2Na1/2) TiO3-0.06Ba(Zr0.02Ti0.98)O3 relaxor ceramics

    DEFF Research Database (Denmark)

    Glaum, Julia; Simons, Hugh; Hudspeth, Jessica

    2015-01-01

    and structural investigation of the polarization reversal process in the prototypical lead-free relaxor 0.94(Bi1/2Na1/2)TiO3-0.06Ba(Zr0.02Ti0.98)O3 reveals that an applied electric field can trigger depolarization and onset of relaxor-like behavior well below TF-R. The polarization reversal process can...... as such be described as a combination of (1) ferroelectric domain switching and (2) a reversible phase transition between two polar ferroelectric states mediated by a non-polar relaxor state. Furthermore, the threshold fields of the second, mediated polarization reversal mechanism depend strongly on temperature....... These results are concomitant with a continuous ferroelectric to relaxortransition occurring over a broad temperature range, during which mixed behavior is observed. The nature of polarization reversal can be illustrated in electric-field-temperature (E-T) diagrams showing the electric field amplitudes...

  4. Dielectric and impedance studies of Ba0.50(Na0.25Bi0.25)(Fe0.25Nb0.25)Ti0.50O3 ceramic

    Science.gov (United States)

    Yadav, Anjana; Chandra, K. P.; Kulkarni, A. R.; Prasad, K.

    2018-05-01

    Lead-free perovskite Ba0.50(Na0.25Bi0.25)(Fe0.25Nb0.25)Ti0.50O3 was prepared using conventional ceramic technique at 1130°C/4h in air atmosphere and characterized by X-ray diffraction, scanning electron microscopy, dielectric and impedance studies. XRD analysis of the compound indicated the formation of a single-phase cubic structure. SEM study was carried out to study the quality and purity of the compound. Compound showed very high dielectric constant (33700). Impedance analysis indicated the negative temperature coefficient of resistance character of the compound. Ac conductivity data followed Jonscher's law and correlated barrier hopping successfully explained the charge carrier transport mechanism in the system.

  5. Qualitative analysis of As, Ba, Cd, Cr, Zn, Fe, Mn, K, Hg, Pb y Cu, as constituents of Amatitlan Lake sediment by XRF

    International Nuclear Information System (INIS)

    Beltran, P.A.E.; Morales, E.A.

    1987-10-01

    Samples of fifteen sampling points were analyzed. Molybdenum X-ray tube with secondary excitation assembly, SiLi detector and deconvolution software AXIL were employed; self-standardization method based upon incoherent ratio was used for quantitative analysis of some elements. Ca, P, S, Ti, Mn, Fe, Cr, Zn, Cu, Ni, Ga, As, Pb, Ge, Sr and Pb, were found. As, Pb and Cu concentrations lower than 109 mg/lt, 119 mg/lt, and 500mg/lt, respectively, were measured. Hg was not detected. (author)

  6. Synthesis of BaBi0.2Co0.35Fe0.45O3−δ by a novel aqueous soft chemical method and its characterizations

    International Nuclear Information System (INIS)

    Islam, Quazi Arif; Raja, Mir Wasim; Basu, Rajendra Nath

    2014-01-01

    Highlights: • Novel combustion process developed first time to synthesize BaBi 0.2 Co 0.35 Fe 0.45 O 3−δ . • The synthesis method is techno-economically viable. • During synthesis, thermal behavior of different complexes studied in detail. • Almost full densification (∼98%) is obtained in sintered samples. • Highest electrical conductivity of 10.38 S cm −1 is obtained at 800 °C. -- Abstract: BaBi 0.2 Co 0.35 Fe 0.45 O 3−δ (BBCF) single phase perovskite has been successfully synthesized by a novel alanine assisted soft chemical combustion method. Thermal behavior of metal alanine complexes during combustion to form BBCF perovskite structure has been studied in detail. X-ray diffraction patterns reveal that the formation of single phase BBCF perovskite proceeds by formation of several intermediate phases. A single phase BBCF powder is obtained at a temperature of 950 °C. Homogeneous distribution of multiple dopants in BBCF matrix is confirmed by elemental mapping using FESEM. The electrical conductivity reveals that with the increase in sintering temperature, conductivity of BBCF increases, reaches to a maximum value of 10.38 S cm −1 at 800 °C when measured in air for samples sintered at 950 °C and upon further increase in sintering temperature, the conductivity decreases gradually. Up to 800 °C, BBCF shows a semiconducting behavior and subsequently follows metallic conduction above 800 °C while performing electrical conductivity measurement in air

  7. Evolution of phase transformation behavior and dielectric temperature stability of BaTiO3–Bi(Zn0.5Zr0.5)O3 ceramics system

    International Nuclear Information System (INIS)

    Wang, Yiliang; Chen, Xiuli; Zhou, Huanfu; Fang, Liang; Liu, Laijun; Zhang, Hui

    2013-01-01

    Highlights: ► (1 − x)BaTiO 3 –xBi(Zn 0.5 Zr 0.5 )O 3 ceramics were synthesized. ► A systematic structural change was observed near x = 0.07 and x = 0.4. ► A change from a normal ferroelectric behavior to diffusive and dispersive relaxor-like characteristic was also observed. ► (1 − x)BT–xBZZ ceramics show good dielectric temperature stability over a wide temperature range. - Abstract: (1 − x)BaTiO 3 –xBi(Zn 0.5 Zr 0.5 )O 3 [(1 − x)BT–xBZZ, 0.01 ⩽ x ⩽ 0.6] ceramics were synthesized by solid-state reaction technique. Based on the X-ray diffraction data analysis, a systematic structure change from the ferroelectric tetragonal phase to pseudocubic phase and the pseudocubic phase to orthorhombic phase was observed near x = 0.07 and x = 0.4 at room temperature, respectively. Dielectric measurements show a dielectric anomaly, over the temperature range from 50 to 200 °C for the compositions with 0.03 ⩽ x ⩽ 0.09. A change from a normal ferroelectric behavior to diffusive and dispersive relaxor-like characteristic was also observed. Moreover, (1 − x)BT–xBZZ ceramics show good dielectric temperature stability over a wide temperature range, which indicates that these ceramics can be applied in the temperature stability devices.

  8. Effect of pelletization pressure on structural properties and critical current hysteresis of ceramic superconducting Bi sub 1 sub . sub 7 Pb sub 0 sub . sub 3 Sr sub 2 Ca sub 2 Cu sub 3 O sub y

    CERN Document Server

    Tepe, M; Abukay, D

    2003-01-01

    The effect of pelletization pressures on structural properties and critical current hysteresis of Bi sub 1 sub . sub 7 Pb sub 0 sub . sub 3 Sr sub 2 Ca sub 2 Cu sub 3 O sub y samples was investigated. The samples used in this study were prepared by classical solid-state reaction at the pressures from 100 up to 500 MPa. The obtained samples were characterized by resistance vs. temperature, (R-T), critical current density vs. applied magnetic field, (J sub c -H), material density vs. pressure, (rho-P), XRD, SEM, and EDAX. The results of this study showed that the quality of electrical and structural properties of Bi-2223 bulk superconductors strongly depends on the pelletization pressure. Pressing of bulk samples at 400 MPa produces textured grain alignment and associates microstructural modifications in order to enhance flux pinning and thus increases current carrying capacities. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  9. Observation of a three-dimensional vortex-line liquid in a highly c-axis-oriented (Bi,Pb)2Sr2Ca2Cu3Ox silver-sheathed tape

    International Nuclear Information System (INIS)

    Sun, Y.; Xu, G.; Du, J.; Zhou, Y.; Zeng, R.; Fu, X.; Hua, P.; Zhang, Y.

    1996-01-01

    We have measured the temperature dependence of resistance of a highly c-axis-oriented (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O x silver-sheathed tape in the mixed state using the dc flux transformer geometry. In the vortex fluid regime, we have observed the onset of a nonlocal conductivity which corresponds to the peak (T peak ) in R bot (T) curves. This can be explained qualitatively in terms of the vortex decoupling which arises from an increased thermal fluctuation. At T peak , the vortices are three dimensional (3D) in character. This behavior is quite different from the results obtained recently by Safar et al. [Phys. Rev. Lett. 69, 824 (1992)] and Busch et al. [Phys. Rev. Lett. 69, 522 (1992)] in Bi 2 Sr 2 CaCu 2 O y single crystals using the same measuring method. Their results show that the vortices are two dimensional in character. The difference of the vortex dimensionality between (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O x and Bi 2 Sr 2 CaCu 2 O y superconductors in the vortex liquid regime may be attributed to different anisotropies due to their different crystal structures and pinning disorders. In a 3D vortex line liquid, the results reveal that dissipation seems to originate from the thermally activated plastic motion of a pinned vortex line liquid. The field and temperature dependence of the activation energy is as follows: U(H,T)=U 0 (1-T/T c )H -0.45 . copyright 1996 The American Physical Society

  10. Inhomogeneous electronic structures in heavily Pb-doped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} single crystals probed by low temperature STM/STS

    Energy Technology Data Exchange (ETDEWEB)

    Kinoda, Go; Nakao, Shoichiro; Motohashi, Teruki; Nakayama, Yuri; Shimizu, Keisuke; Shimoyama, Junichi; Kishio, Koji; Hanaguri, Tetsuo; Kitazawa, Koichi; Hasegawa, Tetsuya

    2003-05-15

    We have performed cryogenic scanning tunneling microscopy/spectroscopy (STM/STS) of heavily Pb-doped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} single crystals to investigate local electronic structures in the overdoped regime. The obtained STM/STS results at 4.3 K clearly showed local inhomogeneity of gap structure {delta} ({delta}=20-60 meV) in a scale of several nm, suggesting the coexistence of superconducting and pseudogap-like regions, even in the overdoped regime.

  11. Electric-field-induced strain contributions in morphotropic phase boundary composition of (Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-BaTiO{sub 3} during poling

    Energy Technology Data Exchange (ETDEWEB)

    Khansur, Neamul H.; Daniels, John E. [School of Materials Science and Engineering, UNSW Australia, New South Wales 2052 (Australia); Hinterstein, Manuel [School of Materials Science and Engineering, UNSW Australia, New South Wales 2052 (Australia); Institute for Applied Materials, Karlsruhe Institute for Technology, P.O. Box 3640, 76021 Karlsruhe (Germany); Wang, Zhiyang [School of Materials Science and Engineering, UNSW Australia, New South Wales 2052 (Australia); The Australian Synchrotron, Clayton, Victoria 3168 (Australia); Groh, Claudia [Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Jo, Wook [School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919 (Korea, Republic of)

    2015-12-14

    The microscopic contributions to the electric-field-induced macroscopic strain in a morphotropic 0.93(Bi{sub 1/2}Na{sub 1/2}TiO{sub 3})−0.07(BaTiO{sub 3}) with a mixed rhombohedral and tetragonal structure have been quantified using full pattern Rietveld refinement of in situ high-energy x-ray diffraction data. The analysis methodology allows a quantification of all strain mechanisms for each phase in a morphotropic composition and is applicable to use in a wide variety of piezoelectric compositions. It is shown that during the poling of this material 24%, 44%, and 32% of the total macroscopic strain is generated from lattice strain, domain switching, and phase transformation strains, respectively. The results also suggest that the tetragonal phase contributes the most to extrinsic domain switching strain, whereas the lattice strain primarily stems from the rhombohedral phase. The analysis also suggests that almost 32% of the total strain is lost or is a one-time effect due to the irreversible nature of the electric-field-induced phase transformation in the current composition. This information is relevant to on-going compositional development strategies to harness the electric-field-induced phase transformation strain of (Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-based lead-free piezoelectric materials for actuator applications.

  12. Microstructure, Piezoelectric, and Ferroelectric Properties of BZT-Modified BiFeO3-BaTiO3 Multiferroic Ceramics with MnO2 and CuO Addition

    Science.gov (United States)

    Guan, Shibo; Yang, Huabin; Chen, Guangcong; Zhang, Rui

    2018-02-01

    A new lead-free piezoelectric ceramic, 0.67BiFeO3-0.33BaTiO3-xBi(Zn0.5Ti0.5) O3 + 0.0035MnO2 + 0.004CuO, was prepared through the solid-state reaction route. The ceramic was sintered in the 950-990°C range. In this paper, the crystal structure of the sample is pure perovskite structure with a pseudo-cubic structure in the range of x = 0-0.05, and does not change greatly with the increase of x. The grain size increases first and then decreases with the increase of x. The addition of Bi(Zn0.5Ti0.5) O3(BZT) promoted the grain growth of the sample. The piezoelectric constant reached the maximum value of d 33 = 188 pC/N, electromechanical coupling coefficient k p = 0.301 and the remanent polarization P r = 61.20 μC/cm2 at x = 0.03. It has a high Curie temperature of T c = 420°C. On the other hand, the depolarization temperature reaches the maximum value, T d = 426°C, at x = 0. A small amount of BZT doping can improve the piezoelectric, dielectric, and ferroelectric properties of the samples. Therefore, this material can be considered as a promising lead-free piezoelectric ceramic material in the application field of high-temperature materials.

  13. Piezoelectric properties of lead-free submicron-structured (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics from nanopowders

    International Nuclear Information System (INIS)

    Pardo, Lorena; García, Alvaro; Brebøl, Klaus; Mercadelli, Elisa; Galassi, Carmen

    2010-01-01

    Submicron-structured (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 (BNBT6) ceramics were obtained from nanometric powder synthesized by sol–gel auto-combustion at 500 °C. Hot-pressing at low temperatures and a combination of this with recrystallization, still moderate in order to reduce the loss of volatile elements, have been tested. Material properties, including all losses, were determined at the resonances of thin discs using Alemany et al software. Ceramics hot-pressed at 700–800 °C for 2 h have a pseudo-cubic structure, a grain size of a few hundred nanometers and are homogeneous. Both their crystal structure and the lack of sintering prevent their poling. For ceramics hot-pressed at 950 °C for 3 h, Bi or Bi 0.5 Na 0.5 loss, together with low piezoelectric properties (d 33 = 60 pC N −1 , k p = 8.3% and k t = 9.5%), was observed. Recrystallization at 1000 °C-1 h of ceramics hot-pressed at 700 and 800 °C for 2 h keeps the submicron structure, reduces porosity and prevents off-stoichiometry. Mechanical and piezoelectric losses are also reduced and coupling factors increased (k p = 24.6%, k t = 36.4%). The best piezoelectric coefficient obtained in these ceramics (d 33 = 143 pC N −1 ) is comparable with those reported for coarse-grained ceramics

  14. Microscopic fracture of filaments and its relation to the critical current under bending deformation in (Bi,Pb)2Sr2Ca2Cu3O10 composite superconducting tapes

    International Nuclear Information System (INIS)

    Hojo, Masaki; Nakamura, Mitsuhiro; Matsuoka, Tomoe; Tanaka, Mototsugu; Ochiai, Shojiro; Sugano, Michinaka; Osamura, Kozo

    2003-01-01

    The strain dependence of the critical current, I c , of (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10 (Bi2223)/Ag/Ag-Mg composite superconducting tapes has been studied both experimentally and analytically under bending deformation. Tests have been carried out for one type of tape used in the VAMAS bending round-robin programme. The complex stress-strain behaviour of each component was first analysed in tension. This was done by comparing the stress-strain curves of composite tapes with those of Ag and Ag-Mg alloy tapes. Here, the plastic deformation (work hardening) of Ag and Ag-Mg alloy, and the thermal residual strain due to the manufacturing process were taken into account. The fracture strain of Bi2223 filaments was inversely determined as 0.08% to meet the global tensile stress-strain curve of the composite tape. The calculated stress-strain curves finally agreed well with the experimental results when the as-supplied bending strain was taken into account. Then, the analysis was modified to fit the bending deformation. Here, the movement of the neutral axis due to the non-symmetric and elastic-plastic stress-strain curves of the components and their Bauschinger effect were taken into account. The relative decrease of I c with the increase in the Bi2223 tape curvature was calculated from the volume fraction of the broken filaments. The calculated I c agreed well with the experimental results when the movement of the neutral axis and the Bauschinger effect were taken into account. Microscopic observation of the spatial distribution of the filament fracture indicated that the damage occurred at the outermost layer on the tensile side when the curvature was small, and then the damage front shifted to the inside layers. The observed fracture behaviour of the Bi2223 filament agreed well with the estimated location based on the above analysis

  15. Sensitive stripping voltammetric determination of Cd(II) and Pb(II) by a Bi/multi-walled carbon nanotube-emeraldine base polyaniline-Nafion composite modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Zhao, Guo; Yin, Yuan; Wang, Hui; Liu, Gang; Wang, Zhiqiang

    2016-01-01

    Highlights: • A MWCNT-EBP-NA composite film modified GCE was fabricated and characterized. • The GCE modified with the MWCNT-EBP-NA composite film exhibited excellent performance in the analysis of Cd(II) and Pb(II) by SWASV. • The Cd(II) and Pb(II) detection limits of the developed electrode were approximately 0.06 μg/L and 0.08 μg/L, respectively. • Bi/MWCNT-EBP-NA/GCE was successfully used to determine metal ions in soil samples. - Abstract: In this study, a multi-walled carbon nanotube (MWCNT)-emeraldine base polyaniline (EBP)-Nafion (NA) composite modified glassy carbon electrode (MWCNT-EBP-NA/GCE) was prepared and used for the sensitive detection of trace Pb(II) and Cd(II), with a detection limit of 0.06 μg/L for Cd(II) and 0.08 μg/L for Pb(II) (S/N = 3), by square wave anodic stripping voltammetry (SWASV). A bismuth film was prepared through the in situ plating of bismuth on the MWCNT-EBP-NA/GCE. The morphologies and electrochemical properties of the modified electrode were characterized by SWASV, scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The parameters affecting the stripping current response were investigated and optimized. The formed MWCNTs in the composite film enlarged the specific surface area of the electrode and significantly promoted electron transferring, and the formed polyaniline (PANI) enhanced the ion-exchange capacity and prevented the macromolecules in real samples from absorbing onto the surface of the electrode. The presence of NA effectively increased the stability and adhesion of the composite film, enhanced the cation-exchange capacity and improved the ability to preconcentrate metal ions. Under the optimized conditions, a linear range of 1.0 to 50.0 μg/L was achieved for both metal ions, with a detection limit of 0.06 μg/L for Cd(II) and 0.08 μg/L for Pb(II) (S/N = 3), offering good repeatability. Finally, the Bi/MWCNT-EBP-NA/GCE was used for the

  16. Specific heat and thermodynamic functions of uranovanadates of the M2+(VUO6)2 · nH2O series (M2+ = Mg, Ca, Sr, Ba, Pb)

    International Nuclear Information System (INIS)

    Karyakin, N.V.; Chernorukov, N.G.; Sulejmanov, E.V.; Trostin, V.L.; Alimzhanov, M.I.; Razuvaeva, E.A.

    1999-01-01

    Isobaric specific heat of crystal uranovanadates Ca(VUO 6 ) 2 · 8H 2 O, Ba(VUO 6 ) 2 · 4H 2 O in the temperature range of 10 - 300 K and of M 1 (VUO 6 ) 2 · 5H 2 O, (M 1 = Mg, Ca, Sr, Pb) at 80 -300 K are measured by the method of adiabatic vacuum calorimetry. The functions H 0 (T) - H 0 (0), S 0 (T), G 0 (T) - H 0 (T) for all the above-mentioned compounds in the range of 0 - 300 K have been calculated, the standard entropies and Gibbs functions of uranovanadates formation at 298.15 K being calculated as well [ru

  17. Spectroscopic, Elemental and Thermal Analysis, and Positron Annihilation Studies on Ca(II), Sr(II), Ba(II), Pb(II), and Fe(III) Penicillin G Potassium Complexes

    Science.gov (United States)

    Refat, M. S.; Sharshara, T.

    2015-11-01

    The [Pb(Pin)2] · 3H2O, [M(Pin)(H2O)2(Cl)] · nH2O (M = SrII, CaII or BaII; n = 0-1), and [Fe(Pin)2(Cl)(H2O)] · H2O penicillin G potassium (Pin) complexes were synthesized and characterized using elemental analyses, molar conductivity, thermal analysis and electronic spectroscopy techniques. The positron annihilation lifetime (PAL) and Doppler broadening (DB) techniques have been employed to probe the defects and structural changes of Pin ligand and its complexes. The PAL and DB line-shape parameters were discussed in terms of the structure, molecular weight, ligand-metal molar ratio, and other properties of the Pin complexes.

  18. Heavily doped M1−xUxF2+2x fluorites studied by quasielastic neutron scattering(M=Ba) and specific heat measurements (M=Pb)

    DEFF Research Database (Denmark)

    Andersen, Niels Hessel; Clausen, Kurt Nørgaard; Kjems, Jørgen

    1983-01-01

    of doping is an increase of the thermally generated defect concentration; at high temperatures the effect is reversed. The microscopic defect structure of Ba0.9U0.1F2.2 has been studied by diffuse quasielastic neutron scattering experiments at room temperature. The experimental observations are in good......The thermal generation of defects in pure and doped Pb1−xUxF2+2x (x=0, 0.05and0.10) has been studied by specific heat measurements between 475 k and 875 k. A simple phenomenological mean field thermodynamic model has been developed and used to interpret the data. At low temperatures the result...

  19. Electrocaloric effect and freezing temperature in (Pb0.8Ba0.2[(Zn1∕3Nb2∕30.7Ti0.3]O3 relaxor ferroelectric ceramic

    Directory of Open Access Journals (Sweden)

    A. Peláiz-Barranco

    2016-09-01

    Full Text Available The electrocaloric effect (ECE is studied in (Pb0.8Ba0.2[(Zn1∕3Nb2∕30.7Ti0.3]O3 relaxor ferroelectric ceramic by using an “indirect method”. The electric dependence for the polarization (hysteresis loops has been obtained for several temperatures showing typical relaxor characteristics. The temperature change ΔT, which is associated with the ECE, is calculated by using the temperature dependence for the polarization. A maximum value for ΔT is observed for temperatures close above the freezing temperature, showing an indirect evidence of that critical temperature. The results are discussed considering the contribution of the polar nanoregions to the polarization.

  20. Experimental Cross Sections for Reactions of Heavy Ions and 208Pb, 209Bi, 238U, and 248Cm Targets

    Energy Technology Data Exchange (ETDEWEB)

    Patin, Joshua Barnes [Univ. of California, Berkeley, CA (United States)

    2002-01-01

    The study of the reactions between heavy ions and 208Pb, 209Bi, 238U, and 248Cm Cm targets was performed to look at the differences between the cross sections of hot and cold fusion reactions. Experimental cross sections were compared with predictions from statistical computer codes to evaluate the effectiveness of the computer code in predicting production cross sections. Hot fusion reactions were studied with the MG system, catcher foil techniques and the Berkeley Gas-filled Separator (BGS). 3n- and 4n-exit channel production cross sections were obtained for the 238U(18O,xn)256-xFm, 238U(22Ne,xn)260-xNo, and 248Cm(15N,xn)263-xLr reactions and are similar to previous experimental results. The experimental cross sections were accurately modeled by the predictions of the HIVAP code using the Reisdorf and Schaedel parameters and are consistent with the existing systematics of 4n exit channel reaction products. Cold fusion reactions were examined using the BGS. The 48Pb(238Ca,xn)256-xNo, 208Pb(50Ti,xn)258-xRf, 208Pb(51V,xn)259-xDb, 50Bi(238Ti,xn)259-xDb, and 209Bi(51V,xn)260-xSg reactions were studied. The experimental production cross sections are in agreement with the results observed in previous experiments. It was necessary to slightly alter the Reisdorf and Schaedel parameters for use in the HIVAP code in order to more accurately model the experimental data. The cold fusion experimental results are in agreement with current 1n- and 2n-exit channel systematics.