Magnetic properties of PrMn2-xFexGe2-57Fe Moessbauer spectroscopy

International Nuclear Information System (INIS)

Wang, J L; Campbell, S J; Cadogan, J M; Tegus, O; Studer, A J; Hofmann, M

2006-01-01

We have investigated the magnetic behaviour of PrMn 2-x Fe x Ge 2 compounds with x = 0.4, 0.6 and 0.8 over the temperature range 4.2-350 K using ac magnetic susceptibility, dc magnetization and 57 Fe Moessbauer effect spectroscopy, as well as neutron diffraction for the PrMn 1.2 Fe 0.8 Ge 2 compound. Replacement of Mn with Fe leads to contraction of the unit cell and a shortening of the Mn-Mn spacing, resulting in modification of the magnetic structure. PrMn 1.6 Fe 0.4 Ge 2 is an intralayer antiferromagnet at room temperature and ferromagnetic below T C inter ∼230 K with additional ferromagnetic ordering of the Pr sublattice detected below T C Pr ∼30 K. Re-entrant ferromagnetism has been observed in PrMn 1.4 Fe 0.6 Ge 2 with four magnetic transitions (T N intra ∼333 K, T C inter ∼168 K, T N inter ∼152 K and T C Pr ∼40 K). Moreover, it was found that T C inter and T C Pr increase with applied field while T N inter decreases. PrMn 1.2 Fe 0.8 Ge 2 is antiferromagnetic with T N intra ∼242 K and T N inter ∼154 K. The magnetic transition temperatures for all compounds are also marked by changes in the 57 Fe magnetic hyperfine field and the electric quadrupole interaction parameters. The 57 Fe transferred hyperfine field at 4.5 K in PrMn 1.6 Fe 0.4 Ge 2 and PrMn 1.4 Fe 0.6 Ge 2 is reduced (below the ordering temperature of the Pr sublattice) compared with that at 80 K (above T C Pr ), indicating that the transferred hyperfine field from Pr acts in the opposite direction to that from the Mn atoms. The neutron data for PrMn 1.2 Fe 0.8 Ge 2 demonstrate that an anisotropic thermal expansion occurs within the interplanar antiferromagnetic range

High pressure Moessbauer spectroscopy of perovskite iron oxide

International Nuclear Information System (INIS)

Nasu, Saburo; Suenaga, Tomoya; Morimoto, Shotaro; Kawakami, Takateru; Kuzushita, Kaori; Takano, Mikio

2003-01-01

High-pressure 57 Fe Moessbauer spectroscopy using a diamond anvil cell has been performed for perovskite iron oxides SrFeO 3 , CaFeO 3 and La 1/3 Sr 2/3 O 3 . The charge states and the magnetic dependency to pressure were determined. Pressure magnetic phase diagrams of these perovskite iron oxides are determined up to about 70 GPa. To be clear the magnetic ordered state, they are measured up to 7.8 T external magnetic fields at 4.5K. The phase transition of these perovskite oxides to ferromagnetisms with high magnetic ordered temperature is observed. In higher pressure, high spin-low spin transition of oxides besides CaFeO 3 is generated. The feature of Moessbauer spectroscopy, perovskite iron oxide and Moessbauer spectroscopy under high pressure are explained. (S.Y.)

Fe-57 Moessbauer effect studies of some ancient Chinese pottery from Xudun

Energy Technology Data Exchange (ETDEWEB)

Yuanfu, Hsia; Zheng, Hu; Rongchuan, Liu; Qi, Zeng; Zhengfang, Yu; Yufang, Zheng

1988-02-01

18 Sherds (4500 B.C.-4000 B.C.) unearthed from different archaeological layers at the same place were studied by Moessbauer spectroscopy. The original firing atmosphere can be deduced from the ratio of the Fe/sup 2+/ to Fe/sup 3+/. By comparing the Moessbauer parameters of the original and the refired sherds, we can assess the original firing temperatures.

57Fe Moessbauer studies on Ni-Mo system in the critical region

International Nuclear Information System (INIS)

Das, D.; Chintalapudi, S.N.; Mukhopadhyay, P.K.; Mookerjee, A.; Mukherjee, G.D.

2001-01-01

Disordered magnetic system NiMo is investigated in the critical region (Mo concentration 10 and 11 wt %) using Moessbauer spectroscopy as a local probe. 57 Co activity has been diffused in the alloy and is used at the source while stainless steel is used as standard absorber. Moessbauer spectrum of the alloy showed a sharp singlet at room temperature which indicates that 57 Co atoms have gone to the substitutional site. Below 200 K, Moessbauer spectra indicate complicated hyperfine interactions and more than one magnetic phase in the samples. Moessbauer results are corroborated by ac susceptibility, resistivity and positron annihilation Doppler broadening measurements. (author)

Moessbauer spectroscopy study on the hydrothermal transformation α-FeOOH → α-Fe2O3

International Nuclear Information System (INIS)

Barb, D.; Diamandescu, L.; Mihaila-Tarabsanu, D.; Rusi, A.; Moraria, M.

1990-01-01

The reaction kinetics of the hydrothermal transformation α-FeOOH→α-Fe 2 O 3 was studied by means of Moessbauer spectroscopy. From the reaction isotherms, a monomolecular, first order reaction was found to characterise the hydrothermal transformation of alpha oxihydroxide to the alpha iron oxide. The rate constant as well as the activation energy of this process were determined. No intermediate phases were identified in the hydrothermal samples. The thermodynamic properties of the hydrothermal system α-FeOOH→α-Fe 2 O 3 in correlation with Moessbauer spectroscopy data are discussed. (orig.)

Hydrogenation of FeCoZr-Al2O3 nanocomposites studied by Moessbauer spectroscopy and magnetometry

International Nuclear Information System (INIS)

Saad, A.; Kasiuk, J.; Fedotova, J.; Szilagyi, E.; Przewoznik, J.; Kapusta, Cz.; Marszalek, M.

2009-01-01

Hydrogenation effects on crystalline and magnetic structure of nanocomposites (FeCoZr) x (Al 2 O 3 ) 100-x , 38 ≤ x ≤ 63 at.% are studied by 57 Fe Moessbauer spectroscopy and magnetometry. Variations of local structure, blocking temperature and mean FeCoZr nanoparticles' volume are discussed with respect to (i) composition and (ii) two competing processes-H 2 incorporation and annealing-occurred during treatment in H 2 plasma.

Visible light activated catalytic effect of iron containing soda-lime silicate glass characterized by 57Fe-Moessbauer spectroscopy

International Nuclear Information System (INIS)

Shiro Kubuki; Jun Iwanuma; Yusuke Takahashi; Kazuhiko Akiyama; Ernoe Kuzmann; Hungarian Academy of Sciences, Budapest; Tetsuaki Nishida

2014-01-01

A relationship between local structure and visible light activated catalytic effect of iron containing soda lime silicate glass with the composition of 15Na 2 O·15CaO·xFe 2 O 3 ·(70-x)SiO 2 , x = 5-50 mass %, abbreviated as NCFSx was investigated by means of 57 Fe-Moessbauer spectroscopy, X-ray diffractometry (XRD), small angle X-ray scattering (SAXS), electrospray ionization mass spectrometry (ESI-MS) and ultraviolet-visible light absorption spectroscopy (UV-Vis). Moessbauer spectra of NCFSx glass with 'x' being equal to or larger than 30 after isothermal annealing at 1,000 deg C for 100 min consisted of a paramagnetic doublet and a magnetic sextet. The former had isomer shift (δ) of 0.24 mm s -1 and quadrupole splitting (Δ) of 0.99 mm s -1 due to distorted Fe III O 4 tetrahedra, and the latter had δ of 0.36 mm s -1 and internal magnetic field (H int ) of 51.8 T due to hematite (α-Fe 2 O 3 ). The absorption area (A) of α-Fe 2 O 3 varied from 47.2 to 75.9, 93.1, 64.8 and 47.9 % with 'x' from 30 to 35, 40, 45 and 50, indicating that the amount of precipitated α-Fe 2 O 3 varied with the Fe 2 O 3 content of NCFSx glass. The precipitation of α-Fe 2 O 3 was also confirmed by XRD study of annealed NCFS glass with 'x' larger than 30. A relaxed sexted with δ, H int and Γ of 0.34 mm s -1 and 37.9 T and 1.32 mm s -1 was observed from the Moessbauer spectra of annealed NCFSx glass with 'x' of 45 and 50, implying that the precipitation of non-stoichiometric iron hydroxide oxide with the composition of Fe 1.833 (OH) 0.5 O 2.5 having the similar structure of α-Fe 2 O 3 and α-FeOOH. A remarkable decrease in the concentration of methylene blue (MB) from 10 to 0.0 μmol L -1 with the first-order rate constant (k) of 2.87 × 10 -2 h -1 was observed for 10-day leaching test using annealed NCFS50 glass under visible light irradiation. ESI-MS study indicated that existence of fragments with m/z value of 129, 117 and 207 etc. originating from MB having m/z of 284. This

Characterization of laves phases in the pseudobinary Zr Cr2-Zr Fe2 system by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Kanter, F.L. de; Badler, C.S.; Granovski, M.; Arias, D.

1988-01-01

57 Fe Moessbauer spectroscopy together with XRD and optical metallography were used to verify the two phase boundaries of the ZrCr 2 -ZrFe 2 pseudobinary phase diagram. Samples with adequate ternary and binary composition, treated at 1450 0 C, were studied. Experimental results indicate that in some cases the two phase boundaries should be modified. (author)

Moessbauer spectroscopy characterization of Zr-Nb-Fe phases

Energy Technology Data Exchange (ETDEWEB)

Ramos, C.P. [CONICET, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina)]. E-mail: ciramos@cnea.gov.ar; Granovsky, M.S. [CAC-CNEA, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Saragovi, C. [CAC-CNEA, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina)

2007-02-01

The aim of this work was the characterization of the ternary phases and of those coming from the corresponding binary systems in the Zr-Nb-Fe diagram by means of Moessbauer spectroscopy. This is part of a complete study involving a tentative isothermal section at 900 deg. C of the center of the Zr-Nb-Fe diagram which will be published elsewhere. Zr-Nb-Fe alloys with Nb contents between 5 and 50 at% and Fe contents between 10 and 60 at% were analyzed after a heat treatment at 900 deg. C for 4 month. Moessbauer characterization of the phases was complemented by optical and scanning electron microscopies, X-ray diffraction and electron microprobe analysis. From the obtained results it can be inferred that Fe in both of the Laves phases present in this system (Zr(FeNb){sub 2} and (ZrNb)Fe{sub 2}) sees different environments, producing quadrupole splitting and hyperfine field distributions, respectively. Two types of body centered cubic {beta} phases (Zr-rich and Nb-rich) were found having noticeable differences in their Moessbauer parameters. Furthermore it was shown that the ternary Fe(NbZr){sub 2} compound would show magnetic character at low temperatures. Concentration dependence of the hyperfine parameters and their relations with the lattice parameters contributed to the structural characterization of the phases.

Moessbauer spectroscopy characterization of Zr-Nb-Fe phases

International Nuclear Information System (INIS)

Ramos, C.P.; Granovsky, M.S.; Saragovi, C.

2007-01-01

The aim of this work was the characterization of the ternary phases and of those coming from the corresponding binary systems in the Zr-Nb-Fe diagram by means of Moessbauer spectroscopy. This is part of a complete study involving a tentative isothermal section at 900 deg. C of the center of the Zr-Nb-Fe diagram which will be published elsewhere. Zr-Nb-Fe alloys with Nb contents between 5 and 50 at% and Fe contents between 10 and 60 at% were analyzed after a heat treatment at 900 deg. C for 4 month. Moessbauer characterization of the phases was complemented by optical and scanning electron microscopies, X-ray diffraction and electron microprobe analysis. From the obtained results it can be inferred that Fe in both of the Laves phases present in this system (Zr(FeNb) 2 and (ZrNb)Fe 2 ) sees different environments, producing quadrupole splitting and hyperfine field distributions, respectively. Two types of body centered cubic β phases (Zr-rich and Nb-rich) were found having noticeable differences in their Moessbauer parameters. Furthermore it was shown that the ternary Fe(NbZr) 2 compound would show magnetic character at low temperatures. Concentration dependence of the hyperfine parameters and their relations with the lattice parameters contributed to the structural characterization of the phases

Moessbauer studies of 57Fe substitution of Cu ions in superconducting oxides

International Nuclear Information System (INIS)

Saitovitch, E.B.

1988-01-01

Since the discovery of high-T c superconductivity in YBa 2 Cu 3 O 7 oxides several studies of metal ions substitutions were reported. The observed depression on T c without a systematic correlation with the charge and magnetic moment of Cu substituents claims for more detailed information about its local properties as can be revealed by 57 Fe Moessbauer spectroscopy. The results for different iron concentrations combined with modifications of the superconducting transition are discussed concerning the presence of magnetic moments on the Fe ions and the preferential occupation of Cu(1) sites, recently confirmed by neutron and electron diffraction experiments. The oxygen coordination for the different iron species are proposed on the basis of their dependence on Fe concentration, their behavior at high temperatures as well as the electron diffraction and electron microscopy measurements reported for Fe: YBa 2 Cu 3 O 7 samples. (author) [pt

57Fe Moessbauer Studies in Mo-Fe Supported Catalysts

International Nuclear Information System (INIS)

Castelao-Dias, M.; Costa, B. F. O.; Quinta-Ferreira, R. M.

2001-01-01

Industrially, the Mo-Fe catalysts used in the selective oxidation of methanol to formaldehyde can rapidly deactivate. The use of support materials may reduce the high temperatures in the catalytic bed and/or increase thermal and mechanical resistance. However, during the preparation of these catalysts, or even during reaction conditions, the active species may react with the support material losing their catalytic activity. In this work silica, silicium carbide and titania were studied as supported catalysts by Moessbauer spectroscopy which proved to be a useful technique in the choice of supported materials

Analysis of biological tissues by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Bonkova, I.; Bujdos, M.; Miglierini, M.

2016-01-01

The aim of this work was to analyze of biological tissues by Moessbauer spectroscopy in terms of demonstration of the magnetic properties of iron and its structural positions. Lyophilized samples of the human brain, human and equine spleen were used for the analysis. The samples were measured with 57 Fe Moessbauer spectroscopy in transmission arrangement at room temperature (∼ 300 K) and at a temperature of liquid helium (4.2 K). The resulting Moessbauer spectra measured at room temperature had doublet character, which confirms the presence of non-magnetic particles. On the contrary, low-temperature measurements are a superposition of several sextet and one duplicate. Hyperfine parameters obtained are similar to those reported hematite, ferrihydrite or magnetite. (authors)

Mixed phase in cubic and hexagonal HoMn2111Cd PAC and 119Sn, 57Fe Moessbauer studies

International Nuclear Information System (INIS)

Cottenier, S.; Meersschaut, J.; Demuynck, S.; Swinnen, B.; Rots, M.

1998-01-01

Hyperfine parameters on 57 Fe, 119 Sn and 111 Cd substituted into the Mn sublattice were measured by Moessbauer and PAC spectroscopies. From these results it is tentatively concluded that C15 and C14 HoMn 2 are mixed-phase compounds. In C14 HoMn 2 there is no (or small) moment on the 2a site. (orig.)

Moessbauer study of C18N/Fe Langmuir-Blodgett layers

Energy Technology Data Exchange (ETDEWEB)

Kuzmann, Erno [Institute of Chemistry, Eoetvoes Lorand University (Hungary); Telegdi, Judit [Institute of Nanochemistry and Catalysis, Chemical Research Center, HAS (Hungary); Nemeth, Zoltan, E-mail: hentes@chem.elte.hu; Vertes, Attila [Institute of Chemistry, Eoetvoes Lorand University (Hungary); Nyikos, Lajos [Institute of Nanochemistry and Catalysis, Chemical Research Center, HAS (Hungary)

2012-03-15

Langmuir-Blodgett (LB) films of octadecanoyl hydroxamic acid (C18N) complexed with Fe{sup 3 + } ions have been prepared at various subphase pH values. The LB films consisting of different number of layers were investigated by {sup 57}Fe conversion electron Moessbauer spectroscopy (CEM) at room temperature. The CEM detector contained a piece of {alpha}-iron, enriched with {sup 57}Fe, using as an internal standard. The Moessbauer pattern of the C18N/Fe LB films is a doublet with parameters {delta} = 0.35 mm/s and {Delta} = 0.74 mm/s. A gradual increase of the relative occurrence of the doublet compared to the sextet of the internal standard was observed with the increasing number of layers, indicating the nearly uniform distribution of Fe among the LB layers.

An iron-57 Moessbauer spectroscopic study of titania-supported iron- and iron-iridium catalysts

International Nuclear Information System (INIS)

Berry, F.J.; Jobson, S.

1992-01-01

57 Fe Moessbauer spectroscopy shows that titania-supported iron is reduced by treatment in hydrogen at significantly lower temperatures than corresponding silica- and alumina-supported catalysts. The metallic iron formed under hydrogen at 600deg C is partially converted to carbide by treatment in carbon monoxide and hydrogen. In contrast to its alumina- and silica-supported counterparts, the remainder of the titania-supported iron is unchanged by this gaseous mixture. The 57 Fe Moessbauer spectra of EXAFS show that iron and iridium in the titania-supported iron-iridium catalysts are reduced in hydrogen at even lower temperatures and, after treatment at 600deg C, are predominantly present as the iron-iridium alloy. The treatment of these reduced catalysts in carbon monoxide and hydrogen is shown by Moessbauer spectroscopy and EXAFS to induce the segregation of iron from the iron-iridium alloy and its conversion to iron oxide. (orig.)

Study of iron valence state and position in sub-site by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Uhm, Young Rang; Lim, Jae Cheong; KIm, Chul Sung; Son, Kwang Jae

2014-01-01

The magnetic ordering temperature and the magnitude of the magnetic fields at the iron sites of YIG can be influenced by substituting, either partially or totally, the Fe 3+ ions at the octahedral and/or the tetrahedral sites with magnetic or diamagnetic ions, and/or by substitution the Y 3+ ions at the dodecahedral sites with magnetic rare earth ions. It has been known for some time that Moessbauer spectroscopy is a powerful method by which iron-containing garnets can be studied. We report here on the synthesis of the compounds with garnet-related structures of composition Y 3 Fe 4.5 Cr 0.5 O 12 and its examination by 57 Fe Moessbauer spectroscopy. The chromium in compounds of the Y 3 Fe 4.5 Cr 0.5 O 12 is distributed at an octahedral site. The Moessbauer spectra can be analyzed using 3 or 4 sets of six Lorentzians with increasing amount of Cr 3+ compounds in this system. It results from the distribution ( 4 C n ) of Fe 3+ and Cr 3+ at an octahedral site. A comparative study of ferrous tablets of Dynabi was carried out using Moessbauer spectroscopy. The obtained results revealed the presence of ferrous (Fe 2+ ) gluconate and ferrous fumarate in a sample. This observation is important to better control the iron state in such medicaments because their pharmaceutical effect in the body is related to the form and valence of iron. The Cr-containing yttrium iron garnet (YIG), and the exchange interactions and site distributions were studied using 57 Fe Moessbauer spectroscopy. The obtained results revealed the presence of ferrous (Fe 2+ ) gluconate and ferrous fumarate in the sample. This observation is important better control the iron state in such medicaments because their pharmaceutical effect in the body is related to the form and valence of iron

Hydrogenation of FeCoZr-Al{sub 2}O{sub 3} nanocomposites studied by Moessbauer spectroscopy and magnetometry

Energy Technology Data Exchange (ETDEWEB)

Saad, A. [Al-Balqa Applied University, Appl. Science Department (Jordan); Kasiuk, J.; Fedotova, J., E-mail: Julia@hep.by [NC PHEP BSU (Belarus); Szilagyi, E. [KFKI Research Institute for Particle and Nuclear Physics (Hungary); Przewoznik, J.; Kapusta, Cz. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science (Poland); Marszalek, M. [Niewodniczanski Institute of Nuclear Physics PAN (Poland)

2009-02-15

Hydrogenation effects on crystalline and magnetic structure of nanocomposites (FeCoZr){sub x}(Al{sub 2}O{sub 3}){sub 100-x}, 38 {<=} x {<=} 63 at.% are studied by {sup 57}Fe Moessbauer spectroscopy and magnetometry. Variations of local structure, blocking temperature and mean FeCoZr nanoparticles' volume are discussed with respect to (i) composition and (ii) two competing processes-H{sub 2} incorporation and annealing-occurred during treatment in H{sub 2} plasma.

Lattice dynamic studies from {sup 151}Eu-Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Katada, Motomi [Tokyo Metropolitan Univ., Hachioji (Japan). Faculty of Science

1997-03-01

New complexes {l_brace}(Eu(napy){sub 2}(H{sub 2}O){sub 3})(Fe(CN){sub 6})4H{sub 2}O{r_brace}{sub x}, bpy({l_brace}(Eu(bpy)(H{sub 2}O){sub 4})(Fe(CN){sub 6})1.5bpy4H{sub 2}O{r_brace}{sub x}) and ({l_brace}(Eu(phen){sub 2}(H{sub 2}O){sub 2})(Fe(CN){sub 6})2phen{r_brace}{sub x}) etc were synthesized using phenanthroline and bipyridine. Lattice dynamic behaviors of Eu and Fe atom in the complexes were investigated by Moessbauer spectroscopy. By {sup 151}Eu-Moessbauer spectrum and parameters of new complexes, bpy complex showed the largest quadrupole splitting value, indicating bad symmetry of Eu ligand in the environment. Molecular structure of napy, bpy and phen complex were shown. These complexes are consisted of Eu atom coordinated with ligand and water molecule, of which (Fe(CN){sub 6}){sup 3-} ion formed one dimentional polymer chain and naphthyridines formed stacking structure. New complexes were observed by {sup 57}Fe-Moessbauer spectroscopy, too. The quadrupole splitting values were very different each other, indicating change of symmetry of Fe atom in the environment and three valence low spin state of Fe in the complex. (S.Y.)

Anthracene as a Non-hygroscopic Diluting Agent for Moessbauer Spectroscopy of Silicate Samples in Moisture-Uptake Studies

International Nuclear Information System (INIS)

Hoffman, E. J.; Bickraj, K.; Denalli, C.

2004-01-01

Anthracene gained no mass when held in a humid chamber and showed no gamma absorption and so appears to be suitable as a replacement for sugars for dilution of moisture-sensitive 57 Fe-Moessbauer spectroscopy samples. Applied to studies of moisture effects on a circumstellar silicate dust simulant, anthracene permitted preparation of sample series for experimental determination of optimal 57 Fe-Moessbauer areal density.

Distribution of iron cations in natural chromites at different stages of oxidation: a {sup 57}Fe Moessbauer investigation

Energy Technology Data Exchange (ETDEWEB)

Pal, Tapan; Mitra, Sachinath [Jadavpur Univ., Calcutta (India). Dept. of Geological Sciences; Moon, Hi-Soo [Yonsei Univ., Seoul (Korea, Republic of). Dept. of Geology

1994-07-01

{sup 57}Fe Moessbauer spectroscopic investigation of natural chromites from two chromite deposits of India (Sukinda and Byrapur) documents partly inverse spinel structure arising out of oxidation. The spectral fitting was based on allowing a disordering distribution of Fe{sup 2+} and Fe{sup 3+} ions at tetrahedral (A) and octahedral (B) sites. Moessbauer investigation of the samples taken from the physico-chemically distinct two horizons of Sukinda viz. brown ore and grey ores, and Byrapur area revealed three types of iron ion distribution as: Fe{sup 2+}(A), Fe{sup 3+}(A) and Fe{sup 2+}(B) (GC-group); (b)Fe{sup 3+}(A{sub 1}), Fe{sup 3+}(A{sub 2}) and Fe{sup 2+}(B) (BC-2 group), and (c) Fe{sup 3+}(A{sub 1}), Fe{sup 3+}(B) (BC-1 group). The distribution pattern of iron cations at A and B sites was linked to the degree of oxidation. These stages of oxidation could be modelled from normal to inverse form. A model suggesting `electron localisation` at the B-sites makes the intermediate stage. Iron site occupancy determined by Moessbauer spectroscopy of the presently studied samples indicates that these fall under three groups of oxidation stages. An early stage of oxidation is shown by samples of group GC, intermediate stage by group BC-2 and final stage by BC-1 group of chromite samples. The imprint of progressive oxidation manifested by Fe cation site occupancy has been correlated with the Fe{sup 2+}/{Sigma}Fe ratios, obtained for each group of samples. (author). 39 refs., 2 figs., 3 tabs.

Moessbauer studies of SnO2 powders doped with dilute 57Fe, prepared by a sol-gel method

International Nuclear Information System (INIS)

Nomur, K.; Sakuma, J.; Takeda, M.

2006-01-01

Diluted magnetic semiconductor (DMS) is prospected as new materials with both semiconductor and magnetic properties. In order to confirm these phenomena, we prepared the powders of SnO 2 doped with various amount of 57 Fe by a sol-gel method. Various compositions of Sn 1-x 57 Fe x O 2 were obtained by mixing some ratio of Fe 3+ nitrate solution and acetylacetonate Sn 4+ complex in the ethylene glycol and citric acid solution. The solutions were evaporated, ashed at around 200 grad C, and finally annealed at 500 grad C, 600 grad C, and 650 grad C, respectively. These Sn 1-x 57 Fe x O 2 (x=0.005, 0.01, 0.03 and 0.05) were measured by XRD, VSM, and Moessbauer spectrometry. The prepared powder samples were confirmed to be a rutile structure, but iron compounds were not detected by XRD. Moessbauer spectra of Sn 1-x 57 Fe x O 2 prepared at 500 grad C were shown in Fig. 1. A small amount of broad sextets were observed in MS spectra of Sn 1-x 57 Fe x O 2 in addition to paramagnetic components. The relative intensity seems to be strong with the decrease of the amount of doped Fe. Moessbauer spectrum at 10 K shows clearly the magnetic components. The magnetic sextet was observed in MS spectra of samples prepared at 650 grad C, but the magnetic behavior weakened because of antiferromagnetic α-Fe 2 O 3 , produced due to the phase separation at high temperatures. (authors)

Study of iron valence state and position in sub-site by Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Uhm, Young Rang; Lim, Jae Cheong; KIm, Chul Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Son, Kwang Jae [Kookmin Univ., Seoul (Korea, Republic of)

2014-05-15

The magnetic ordering temperature and the magnitude of the magnetic fields at the iron sites of YIG can be influenced by substituting, either partially or totally, the Fe{sup 3+} ions at the octahedral and/or the tetrahedral sites with magnetic or diamagnetic ions, and/or by substitution the Y{sup 3+} ions at the dodecahedral sites with magnetic rare earth ions. It has been known for some time that Moessbauer spectroscopy is a powerful method by which iron-containing garnets can be studied. We report here on the synthesis of the compounds with garnet-related structures of composition Y{sub 3}Fe{sub 4.5}Cr{sub 0.5}O{sub 12} and its examination by {sup 57}Fe Moessbauer spectroscopy. The chromium in compounds of the Y{sub 3}Fe{sub 4.5}Cr{sub 0.5}O{sub 12} is distributed at an octahedral site. The Moessbauer spectra can be analyzed using 3 or 4 sets of six Lorentzians with increasing amount of Cr{sup 3+} compounds in this system. It results from the distribution ({sub 4}C{sub n}) of Fe{sup 3+} and Cr{sup 3+} at an octahedral site. A comparative study of ferrous tablets of Dynabi was carried out using Moessbauer spectroscopy. The obtained results revealed the presence of ferrous (Fe{sup 2+}) gluconate and ferrous fumarate in a sample. This observation is important to better control the iron state in such medicaments because their pharmaceutical effect in the body is related to the form and valence of iron. The Cr-containing yttrium iron garnet (YIG), and the exchange interactions and site distributions were studied using {sup 57}Fe Moessbauer spectroscopy. The obtained results revealed the presence of ferrous (Fe{sup 2+}) gluconate and ferrous fumarate in the sample. This observation is important better control the iron state in such medicaments because their pharmaceutical effect in the body is related to the form and valence of iron.

57Fe Moessbauer study of amorphous and nanocrystalline Fe73.5Nb3Cu1Si13.5B9 after neutron irradiation

International Nuclear Information System (INIS)

Miglierini, M.; Sitek, J.; Szasz, Z.; Vitazek, K.

1994-01-01

57 Fe Moessbauer spectroscopy is used to study neutron irradiation induced changes in the short-range order of Fe 73.5 Nb 3 Cu 1 Si 13.5 B 9 alloy. The samples are investigated in both amorphous and nanocrystalline states. Neutron irradiation leads to an increase of the standard deviation of a hyperfine field distribution (HFD), implying rearrangement of the atoms towards disordering. Simultaneously, changes in the average value of the hyperfine field and a net magnetic moment position occur as a consequence of a spin reorientation, atom mixing and microscopic stress centres which are introduced by neutron irradiation. (orig.)

In situ57Fe Moessbauer Investigation of Solid-State Redox Reactions of Lithium Insertion Electrodes for Advanced Batteries

International Nuclear Information System (INIS)

Sakai, Yoichi; Ariyoshi, Kingo; Ohzuku, Tsutomu

2002-01-01

A novel in situ electrochemical cell for 57 Fe Moessbauer measurements was developed in order to clarify the mechanisms of solid-state redox reactions in lithium insertion materials containing iron. Our in situ Moessbauer technique was successfully applied to the determination as to which transition metal ion was a redox center in the insertion electrodes, such as LiFe 0.5 Mn 1.5 O 4 , LiFeTiO 4 , or LiFe 0.25 Ni 0.75 O 2 , for the lithium-ion batteries.

A proportional counter for efficient backscatter Moessbauer effect spectroscopy

International Nuclear Information System (INIS)

Pawlowski, Z.; Marzec, J.; Cudny, W.; Holnicka, J.; Walentek, J.

1979-01-01

The authors present a novel gas-tight proportional counter with flat beryllium windows for backscatter Moessbauer spectroscopy. The krypton-filled counter has a geometry that approaches 2π and a resolution of 12% fwhm for the 14.4 keV line of 57 Fe, and is easy to manufacture. (Auth.)

Multiwire proportional chamber for Moessbauer spectroscopy: development and results

International Nuclear Information System (INIS)

Costa, M.S. da.

1985-12-01

A new Multiwere proportional Chamber designed for Moessbauer Spectroscopy is presented. This detector allows transmission backscattering experiments using either photons or electrons. The Moessbauer data acquisition system, partially developed for this work is described. A simple method for determining the frontier between true proportional and semi-proportional regions of operation in gaseous detectors is proposed. The study of the tertiary gas mixture He-Ar-CH 4 leads to a straight forward way of energy calibration of the electron spectra. Moessbauer spectra using Fe-57 source are presented. In particular those obtained with backsattered electrons show the feasibility of depth selective analysis with gaseous proportional counters. (author) [pt

Moessbauer study of 57Fe isolated in NH3 and NH3/Xe matrices

International Nuclear Information System (INIS)

Saitovitch, E.M.B.; Litterst, F.J.; Micklitz, H.

1981-01-01

Moessbauer studies on 57 Fe isolated in solid ammonia and ammonia/xenon mixtures were perfomed at 4.2 K and 77 K. They show clearly that atomic iron reacts only with one ammonia molecule forming FeNH 3 which is stable in an ammonia matrix up to 77 K. In addition a compound is formed which is attributed to an iron (II) hexammine. (Author) [pt

Characterization of clays found in soils of the indian territories in Rio Grande do Sul State by using the 57 Fe Moessbauer spectroscopy

International Nuclear Information System (INIS)

Perez, C.A.S.; Gobbi, D.; Marcos, J.L.N.

2004-01-01

Clay samples collected from soils of indian territories of the middle plateau in Rio Grande do Sul were analyzed with the aim to obtain characterization data and technical parameters for their potential use as raw material for ceramic products. The mineralogical study in samples by using the X-ray diffraction technique demonstrated that the predominant clay mineral is kaolinite. Others minerals as quartz and rutile also are present in small amounts. Chemical analysis shows low percentages for oxides of Mg, Mn, K, Na, Ca, Cu and Zn (overall percentages smaller than 0.97%). The samples also were analyzed with the 57 Fe Moessbauer spectroscopy. The Moessbauer spectra at room temperature confirm the presence of the mineral kaolinite. At 77 K they reveal the existence of the minerals goethite and hematite as ultrafine magnetic particles in a superparamagnetic state. The physical tests performed in the samples show that these soils are very fine material and present appropriate granulometric characteristics and plasticity, which can be taken in advantage for the production of materials for construction or production of ornamental artifacts. (author)

Moessbauer spectroscopy of 57Fe and the evolution of the solar system

International Nuclear Information System (INIS)

Knudsen, J.M.

1990-01-01

The article starts with a brief review of ideas on the origin of the solar system, with emphasis on the cosmic history of the element iron. Some examples of the application of Moessbauer spectroscopy to the study of iron compounds from various types of meteorites, which represent different stages of the evolution of the planetary system, then follow. (orig.)

Gas flow counter conversion electron Moessbauer spectroscopy (GFC-CEMS)

International Nuclear Information System (INIS)

Williamson, A.; Vijay, Y.K.; Jain, I.P.

1999-01-01

Conversion Electron Moessbauer Spectroscopy (CEMS) is well established technique to study surface properties of materials. However non availability of commercial experimental set up and complexity of operational parameters have been restricting the working experimental groups with in the country and abroad. In this paper we have presented the development work for the design of Gas Flow Counter (GFC), e.g. convenient sample mount, grounding, steady flow rate adjustment and minimum He-losses so that the detector operation and installation becomes convenient and dependable. The basic design is modified e.g. large volume to maintain steady gas flow, sample mount close to central wire and O-ring fitted flange. The CEMS spectra are recorded using conventional Moessbauer drive and 57 Co source. The calibrated spectrum shows a detection efficiency of about 20% for natural iron and steel foil. The CEMS spectrum for FeTi bulk and transmission Moessbauer Spectroscopy (TMS) spectrum of FeTi thin film deposited by vacuum evaporation on thin glass substrate were recorded to test the performance of GFC-CEMS. (author)

Contribution to 57Fe ion implanted garnet study by Moessbauer effect

International Nuclear Information System (INIS)

Kornilios, N.

1986-11-01

Due to because of their numerous physical properties, garnets are often used in new technologies. In order to improve their properties, ion implantation of inert gases has been proved to be a powerful technique to elaborate bubble memories. Recently it has been shown that high doses implanted ions, chemically reacting with the matrix could give interesting results. If the bulk is completely amorphized after implantation, further annealings can recrystallize it. In this study Y 3 F 5 O 12 , Y 3 Al 5 O 12 and Gd 3 Ga 5 O 12 single crystals were 100 keV implanted with 57 Fe ions at doses ranging between 10 16 and 10 17 ions cm -2 . The iron chemical states were determined thanks to Conversion Electron Moessbauer Spectroscopy (CEMS) and it was shown that the alloying elements of the matrix could influence the nature of the created phases. After thermal treatments the sample superficial layers were characterized using CEMS, grazing angle X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Rutherford Backscattering Spectroscopy (RBS). Different annealing stages were put forward: the oxidation of the implanted iron below 650 0 C and the garnet recrystallization around 850 0 C with some iron substitution in the garnet octahedral and tetraedral sites. The overstoechiometric iron forms particles of mixed oxides (FeAl) 2 O 3 , (FeGa) 2 O 3 or particles of pure Fe 2 O 3 oxide depending on the garnet. For the first time it is proved that after annealing around 1200-1300 0 C a complete rebuilding of the garnet matrix can induce for these oxide particles at room temperature a Morin transition [fr

Moessbauer spectroscopic studies of the chemical effects associated with 57Co(electron capture)57Fe decay in tris-β-diketonatocobalt(III) compounds

International Nuclear Information System (INIS)

Sakai, Yoichi; Endo, Kazutoyo; Sano, Hirotoshi

1980-01-01

Magnetic hyperfine structures (hfs) were found in the absorption Moessbauer spectra at 78 K of a paramagnetic iron(III) complex diluted in a diamagnetic cobalt(III) or aluminium(III) complex such as 57 Fe(acac) 3 in Co(acac) 3 , 57 Fe(oxin) 3 in Al(oxin) 3 , and 57 Fe(dbm) 3 in Co(dbm) 3 (acac=acetylacetonato, oxin=8-quinolinolato, and dbm=dibenzoylmethanato), showing that the magnetic hfs is caused by the spin-spin relaxation through the surrounding diamagnetic species. In the emission Moessbauer experiments, magnetic hfs was observed at 78 K in 57 Co-labelled Co(dbm) 3 , Co(oxin) 3 , and polystyrene-diluted Co(acac) 3 , while it was not observed in 57 Co-labelled Co(acac) 3 and Co(dpm) 3 (dpm=dipivaloylmethanato). The former possess pi -conjugated systems to a greater extent than the latter, either in the ligands or in the vicinity of the 57 Co-labelled Co(III) species. These results were explained in terms of the radiolytic stabilities of the matrices as well as those of 57 Co-labelled compounds by showing that the paramagnetic radicals produced in a diamagnetic matrix quench the magnetic hfs because of the increased spin-spin interaction, as a consequence of the local radiolysis by EC-decay. (author)

Mixed phase in cubic and hexagonal HoMn{sub 2} {sup 111}Cd PAC and {sup 119}Sn, {sup 57}Fe Moessbauer studies

Energy Technology Data Exchange (ETDEWEB)

Cottenier, S.; Meersschaut, J.; Demuynck, S.; Swinnen, B.; Rots, M. [Leuven Univ. (Belgium). Inst. voor Kern- en Stralingsfysika; Krop, K.; Marzec, J.; Zukrowski, J.; Przewoznik, J.; Japa, E. [Dept. of Solid State Physics, Univ. of Mining and Metallurgy, Krakow (Poland)

1998-01-01

Hyperfine parameters on {sup 57}Fe, {sup 119}Sn and {sup 111}Cd substituted into the Mn sublattice were measured by Moessbauer and PAC spectroscopies. From these results it is tentatively concluded that C15 and C14 HoMn{sub 2} are mixed-phase compounds. In C14 HoMn{sub 2} there is no (or small) moment on the 2a site. (orig.) 6 refs.

Backscattering Moessbauer spectroscopy of Martian dust

International Nuclear Information System (INIS)

Bertelsen, P.; Madsen, M. B.; Binau, C. S.; Goetz, W.; Gunnlaugsson, H. P.; Hviid, S. F.; Kinch, K. M.; Klingelhoefer, G.; Leer, K.; Madsen, D. E.; Merrison, J.; Olsen, M.; Squyres, S. W.

2005-01-01

We report on the determination of the mineralogy of the atmospherically suspended Martian dust particles using backscattering 57 Fe Moessbauer spectroscopy on dust accumulated onto the magnets onboard the Mars Exploration Rovers. The spectra can be interpreted in terms of minerals of igneous origin, and shows only limited, if any, amounts of secondary minerals that may have formed in the presence of liquid water. These findings suggest that the dust has formed in a dry environment over long time in the history of the planet.

Research by Moessbauer and infrared spectroscopy of films of polyacrylonitrile doped with FeCl2 and FeCl3

International Nuclear Information System (INIS)

Santos, Vadilson M. dos; Silva Filho, Eloi A. da; Nunes Filho, Evaristo

2009-01-01

The heating effect on films of polyacrylonitrile and doping of the ions Fe(II) and Fe (III) may reveal important aspects of the use of this polymer in the search for new materials. This paper was done the doping of the films of PAN with ions Fe(II) and Fe (III), with thermo heating is range of 60 a 90 deg C e de 90 a 170 deg C through the alkaline and acid hydrolysis of the CN groups used spectroscopy of FTIR and Moessbauer techniques to evaluate the structural changes results of doping process this polymer. The results showed that the FTIR spectral have a strong interaction of the ions Fe(II) and Fe (III) with PAN and confirmed by Moessbauer data. (author)

High pressure Moessbauer spectroscopy of perovskite iron oxide

CERN Document Server

Nasu, S; Morimoto, S; Kawakami, T; Kuzushita, K; Takano, M

2003-01-01

High-pressure sup 5 sup 7 Fe Moessbauer spectroscopy using a diamond anvil cell has been performed for perovskite iron oxides SrFeO sub 3 , CaFeO sub 3 and La sub 1 sub / sub 3 Sr sub 2 sub / sub 3 O sub 3. The charge states and the magnetic dependency to pressure were determined. Pressure magnetic phase diagrams of these perovskite iron oxides are determined up to about 70 GPa. To be clear the magnetic ordered state, they are measured up to 7.8 T external magnetic fields at 4.5K. The phase transition of these perovskite oxides to ferromagnetisms with high magnetic ordered temperature is observed. In higher pressure, high spin-low spin transition of oxides besides CaFeO sub 3 is generated. The feature of Moessbauer spectroscopy, perovskite iron oxide and Moessbauer spectroscopy under high pressure are explained. (S.Y.)

Low temperature Moessbauer study of amorphous Fe83B17

International Nuclear Information System (INIS)

Miglierini, M.; Sitek, J.

1987-01-01

Information about changes in magnetic structures of metallic glass Fe 83 B 17 at low temperatures has been obtained by 57 Fe Moessbauer spectroscopy in the temperature range from 295 to 77 K. The mean values of the magnetic hyperfine field have been calculated from magnetic splitting of Moessbauer spectra. The angle between the direction of magnetization and the γ-ray direction θ obtained from line intensity ratios is given as a function of temperature. The curve shows a minimum at 120 K. The influence of decreasing temperature on the magnetic structure may be caused by a change in magnetic anisotropy and a reorientation of surface spins. The main contribution to the changes in θ comes from the reorientation of surface domains

Moessbauer spectroscopy of Fe-Mn-Cu alloys

International Nuclear Information System (INIS)

Paduani, Clederson; Krause, Joao Carlos; Yoschida, M.I. Soares

2004-01-01

Full text: Although a continuous series of solid solutions exists between Cu and Mn, Fe and Cu are miscible only a few percent at higher temperatures. In moderately concentrated Cu-Mn alloys the Mn moments are bound to the long ranged antiferromagnetic order and the perpendicular components form an X-Y spin glass. Copper alloys are largely employed in various industrial applications. In this work we study the magnetic properties of iron-rich disordered Fe-Mn-Cu alloys with the bcc structure with the experimental techniques of X-ray diffraction (XRD), Moessbauer spectroscopy (MS) and thermogravimetry (TGA). We investigate the formation of a solid solution with the bcc structure as well as the effect of the composition on the structural and magnetic properties of these alloys. A Rietveld analysis of the XRD diffractograms indicate that all prepared samples are single phase and are well crystallized with a bcc structure. (author)

Moessbauer study of Fe(III)-reducing sugar complexes

International Nuclear Information System (INIS)

Wolowiec, S.; Drabent, K.

1985-01-01

Iron(III) complexes with glucose, galactose, mannose and lactose were prepared. The Moessbauer and magnetic susceptibility data demonstrate the polymeric structure of the complexes. The thermal behaviour of the Fe(III)-glucose complex was monitored by Moessbauer spectroscopy. (author)

Moessbauer spectroscopy on amorphous Fe/sub x/Ni/sub 80-x/B20 after neutron irradiation

International Nuclear Information System (INIS)

Sitek, J.; Miglierini, M.

1985-01-01

Amorphous Fe/sub x/Ni/sub 80-x/B 20 glassy alloys (x = 40, 50, 60, and 70) irradiated with fast neutrons in a fluence range of 10 14 to 10 19 cm -2 were investigated by Moessbauer spectroscopy. There were some significant changes in the Moessbauer spectrum parameters of the 10 19 cm -2 irradiated samples except Fe 40 Ni 40 B 20 . This corresponds to a change in the direction of the easy axis of magnetization. The measurements show that the resistance of the Fe-Ni-B system against neutron irradiation improves with increasing Ni content up to a certain point

Development of a highly efficient conversion electron Moessbauer spectroscopy (CEMS) detector for low temperature (xPb1-x)Te bilayers

International Nuclear Information System (INIS)

Pombo, Carlos Jose da Silva Matos

2006-01-01

The 57 Fe Moessbauer spectroscopy is a nuclear, non-destructive technique used for the investigation of structural, magnetic and hyperfine properties of several materials. It is a powerful tool in characterizing materials in physics, metallurgy, geology and biology field areas, especially magnetic materials, alloys and minerals containing Fe. Lately, the Conversion Electron Moessbauer Spectroscopy (CEMS) is widely used in making studies on ultra-thin magnetic films, as well as other nanostructured materials. In case of magnetic nanostructures, low temperature (LT) studies are especially important due to the possibility of dealing with superparamagnetic effects. In this work it was developed a CEMS measurement system for low temperatures ( R ) and an optical cryostat (Model SVT-400, Janis Research Co, USA), from which the project was originally conceived at the Applied Physics / Moessbauer spectroscopy Department from University of Duisburg-Essen, Germany. The LT-CEMS system was fully built, tested and successfully applied in a preliminary characterization of Fe/(Eu x Pb 1-x )Te(111) bilayers with use of a 15 angstrom, 57 Fe probe layer, with reasonable results at sample temperatures as low as 8 K. (author)

Development of a highly efficient conversion electron Moessbauer spectroscopy (CEMS) detector for low temperature (<20 K) measurements and tests on Fe / (Eu{sub x}Pb{sub 1-x})Te bilayers; Desenvolvimento de um detector de alta eficiencia para espectroscopia Moessbauer de eletrons de conversao (CEMS) a baixas temperaturas (<20K) e testes em bicamadas Fe / (Eu{sub x}Pb{sub 1-x})Te

Energy Technology Data Exchange (ETDEWEB)

Pombo, Carlos Jose da Silva Matos

2006-07-01

The {sup 57}Fe Moessbauer spectroscopy is a nuclear, non-destructive technique used for the investigation of structural, magnetic and hyperfine properties of several materials. It is a powerful tool in characterizing materials in physics, metallurgy, geology and biology field areas, especially magnetic materials, alloys and minerals containing Fe. Lately, the Conversion Electron Moessbauer Spectroscopy (CEMS) is widely used in making studies on ultra-thin magnetic films, as well as other nanostructured materials. In case of magnetic nanostructures, low temperature (LT) studies are especially important due to the possibility of dealing with superparamagnetic effects. In this work it was developed a CEMS measurement system for low temperatures (<20 K) based on a solid-state electron multiplier (Channeltron{sup R}) and an optical cryostat (Model SVT-400, Janis Research Co, USA), from which the project was originally conceived at the Applied Physics / Moessbauer spectroscopy Department from University of Duisburg-Essen, Germany. The LT-CEMS system was fully built, tested and successfully applied in a preliminary characterization of Fe/(Eu{sub x}Pb{sub 1-x})Te(111) bilayers with use of a 15 angstrom, {sup 57} Fe probe layer, with reasonable results at sample temperatures as low as 8 K. (author)

Moessbauer characteristics of glauconitisation

International Nuclear Information System (INIS)

Kuzmann, E.; Weiszburg, T. G.; Toth, E.; Garg, V. K.

2008-01-01

57 Fe Moessbauer spectroscopy, X-ray diffraction and local (WDX, EDX) and bulk chemical methods (ICP-AES complemented with Fe 2+ titration) were used to study glauconites originating from three sandstone samples (NY1, NY3 and EWT) of the Upper Oligocene Eger Formation (Northern Hungary). The, during glauconitisation, increasing aggregate density and magnetic susceptibility offered a unique possibility to separate grains of different evolutionary stage from the same glauconite population. 57 Fe Moessbauer spectra of both structurally and chemically well characterised glauconite fractions were decomposed into four doublets. Two-two of the doublets were assigned to octahedral Fe 2+ and octahedral Fe 3+ . Fe 2+ /Fe values determined by Moessbauer measurements were used for the calculation of the chemical formula of glauconite samples [including octahedral occupancy (B O ) and octahedral charge (X O ) as well]. The gradual increase of Fe 2+ /Fe was documented with the increase of aggregate density in correlation with the foregoing of glauconitisation. Our results give a quantitative demonstration that octahedral occupancy (B O ) decrease and the substitution of octahedral Al by Fe 2+ are the major processes allowing the interlayer K incorporation during glauconitisation. The systematic crystalchemical evolution as reflected in the systematic changes of the Moessbauer data are discussed in terms of the subsequent steps of glauconitisation.

FeRu/TiO2 and Fe/TiO2 catalysts after reduction and Fischer-Tropsch synthesis studied by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Kraan, A.M. van der; Nonnekens, R.C.H.; Niemantsverdriet, J.W.

1986-01-01

A series of TiO 2 -supported bimetallic FeRu catalysts with different Fe:Ru ratios (infinity; 10:1; 3:1; 1:1; 1:3) has been studied by means of in situ Moessbauer spectroscopy. The influence of reduction and Fischer-Tropsch synthesis on the state of iron in the FeRu/TiO 2 catalysts is derived. (Auth.)

Irradiation effects detected by Moessbauer spectroscopy in iron complexes

International Nuclear Information System (INIS)

Ladriere, J.

1998-01-01

The nature and the extent of the 60 Co gamma radiolysis of several iron coordination compounds have been analysed by Moessbauer absorption spectroscopy. The comparison of the radiolytic yields with the after effects observed by Moessbauer emission spectroscopy in similar 57 Co-doped compounds, supports the self-radiolysis model

Application of [sup 57]Fe emission Moessbauer spectroscopy to the investigation of the physico-chemical consequences of the double radioactive decay [sup 57]Ni[yields][sup 57]Co[yields][sup 57]Fe in the solid state

Energy Technology Data Exchange (ETDEWEB)

Devillers, M.; Ladriere, J. (Univ. Catholique de Louvain, Louvain-la-Neuve (Belgium). Lab. de Chimie Inorganique et Nucleaire)

1994-04-01

[sup 57]Fe emission Mossbauer spectroscopy is shown to be a useful technique for investigating the cumulative recoil and Auger after-effects associated with the double electron capture decay, [sup 57]Ni[yields][sup 57]Co''->[sup 57]Fe, in the solid state. Experimental results collected in several types of nickel-containing matrices are surveyed: conducting materials (Ni metal), ionic compounds with monoatomic ligands [potassium trifluoronickelate (II)] and coordination compounds with polyatomic ligands (carboxylates). (Author).

Moessbauer spectroscopy-nuclear hyperfine technique for studying dynamic chemical states of iron complexes

International Nuclear Information System (INIS)

Maeda, Y.

2005-01-01

A brief introduction of Moessbauer spectroscopy will be presented, followed by a discussion of the Moessbauer parameters, isomer shifts, quadrupole splittings, and spectral shapes of complexes in the presence of relaxation of the electronic states of the iron atoms. The usefulness of Moessbauer spectroscopy to demonstrate the dynamic phenomena of electronic states will be discussed in this lecture. (1) The Moessbauer spectra of mixed valence dinuclear and trinuclear iron complexes will be discussed in connection with the chemical structure of the complexes: The values of the quadrupole splittings and isomer shifts of [Fe II Fe III (bpmp) (ppa) 2 ](BF 4 ) 2 increase on raising the temperature, where Hbpmp represents 2,6-bis[bis(2- pyridylmethyl)aminoethyl]-4-methylphenol and ppa is 3-n-phenylpropionic acid. The spectra can be accounted for by postulating intramolecular electron exchange between two energetically inequivalent vibronic states Fe A 2+ Fe B 3+ and Fe A 3+ Fe B 2+ : The apparent time averaged valence states of the iron atoms are 2.2 and 2.8 on the Moessbauer time scale at 293 K. (2) The Moessbauer spectra of iron(III) spin-crossover complexes will be discussed in connection with the spin-transition rate and chemical structure of the complexes. The Moessbauer spectra of spin-crossover iron(III) complexes with LIESST (Light Induced Electronic Spin-State Transition) and of metallomesogens will be discussed to illustrate the extension of this research area by the use of Moessbauer spectroscopy.

[sup 57]Fe Moessbauer study of amorphous and nanocrystalline Fe[sub 73. 5]Nb[sub 3]Cu[sub 1]Si[sub 13. 5]B[sub 9] after neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Miglierini, M. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia)); Sitek, J. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia)); Szasz, Z. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia)); Vitazek, K. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia))

1994-05-01

[sup 57]Fe Moessbauer spectroscopy is used to study neutron irradiation induced changes in the short-range order of Fe[sub 73.5]Nb[sub 3]Cu[sub 1]Si[sub 13.5]B[sub 9] alloy. The samples are investigated in both amorphous and nanocrystalline states. Neutron irradiation leads to an increase of the standard deviation of a hyperfine field distribution (HFD), implying rearrangement of the atoms towards disordering. Simultaneously, changes in the average value of the hyperfine field and a net magnetic moment position occur as a consequence of a spin reorientation, atom mixing and microscopic stress centres which are introduced by neutron irradiation. (orig.)

Moessbauer investigations of itmid

International Nuclear Information System (INIS)

Mrayed, Y.S.; Ellid, M.S.; Fallagh, F.A.

1996-01-01

A sample of itmid available commercially was obtained and investigated using 57 Fe Moessbauer spectroscopy, atomic absorption, X-ray fluorescence. The Moessbauer spectra showed the presence hematite (alpha-Fe 2 O 3 ), goethite (alpha-FeOOH), and a third phase which has a six-line spectrum with the following parameters : Isomer shift (gamma= 0.52 mm/s), magnetic field (H=290 kOe). After conducting a series of reduction and calcination to the itmid sample and with the aid of atomic absorption and X-ray fluorescence results the third phase was identified as the iron sulfide compound FeS. 3 figs., 3 tabs

Moessbauer spectroscopy

International Nuclear Information System (INIS)

Gonser, U.

1975-01-01

This book is addressed to persons interested in learning about what has been done and what can be done with Moessbauer spectroscopy. In an introductory chapter the basic principle is explained and the general parameters governing Moessbauer spectroscopy are tabulated. For the following chapters various disciplines are chosen and the wide applicability of this measuring technique is demonstrated. The second chapter discusses a few representative examples of chemical interesting information being reflected by isomer shifts and quadrupole splittings, particularly with respect to bonding and structural properties. The third chapter deals with some applications of Moessbauer spectroscopy for characterizing magnetic compounds and its use for magnetic structure investigations, particularly by making use of polarized radiation. The fourth chapter describes the use of the Moessbauer spectroscopy for studying iron in biological molecules. As an example of recent applications to mineralogy and geology the results of the studies of lunar samples are reviewed in the fifth chapter. Finally, in the last chapter, work is described on the use of Moessbauer spectroscopy in physical metallurgy, particularly quantitative analyses which have enabled metallurgists to solve many old problems. (orig./FW) [de

57Fe Moessbauer effect in borosilicate glasses

International Nuclear Information System (INIS)

Music, S.

1989-01-01

The present study was carried out to elucidate the valence state of iron and its co-ordination in borosilicate glasses, which are being investigated as possible solidification matrices for the immobilization of a simulated nuclear waste. 57 Fe Mossbauer spectroscopy was used as the experimental technique. The chemical compositions of glass samples and the experimental conditions for the preparation of these samples are given. Iron in the form of haematite (α-Fe 2 O 3 ) was used as doping material. Details of the experimental procedure have previously been described. Isomer shifts are calculated relative to α-iron. The results indicate a strong dependence of the valency of the iron and its coordination on the chemical composition of the glass and the Fe 2 O 3 content. The method of preparing the glasses also influences the state of the iron in oxide glasses. (Author)

Moessbauer spectroscopy studies of spin reorientations in amorphous and crystalline (Co0.2Fe0.8)72.5Si12.5B15 glass coated micro-wires

International Nuclear Information System (INIS)

Nowik, I.; Felner, I.; Garcia-Miquel, H.

2007-01-01

Thermo-gravimetric, differential scanning calorimetry and comprehensive 57 Fe Moessbauer spectroscopy studies of amorphous and crystalline ferromagnetic glass coated (Co 0.2 Fe 0.8 ) 72.5 Si 12.5 B 15 micro-wires have been recorded. The Curie temperature of the amorphous phase is T C (amorp) ∼730 K. The analysis of the Moessbauer spectra reveals that below 623 K the easy axis of the magnetization is axial-along the wires, and that a tangential or/and radial orientation occurs at higher temperatures. At 770 K, in the first 4 hours the Moessbauer spectrum exhibits a pure paramagnetic doublet. Crystallization and decomposition to predominantly α-Fe(Si) and Fe 2 B occurs either by raising the temperature above 835 K or isothermally in time at lower temperatures. Annealing for a day at 770 K, leads to crystallization. In the crystalline material the magnetic moments have a complete random orientation. After cooling back to ambient temperature, both α-Fe(Si) and Fe 2 B in the glass coated wire show pure axial magnetic orientation like in the original amorphous state. The observed spin reorientations are associated with changes in the stress induced by the glass coating

Moessbauer spectroscopy on amorphous Fe/sub x/Ni/sub 80-x/B/sub 20/ after neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Sitek, J.; Miglierini, M. (Slovenska Vysoka Skola Technicka, Bratislava (Czechoslovakia))

1985-05-16

Amorphous Fe/sub x/Ni/sub 80-x/B/sub 20/ glassy alloys (x = 40, 50, 60, and 70) irradiated with fast neutrons in a fluence range of 10/sup 14/ to 10/sup 19/ cm/sup -2/ were investigated by Moessbauer spectroscopy. There were some significant changes in the Moessbauer spectrum parameters of the 10/sup 19/ cm/sup -2/ irradiated samples except Fe/sub 40/Ni/sub 40/B/sub 20/. This corresponds to a change in the direction of the easy axis of magnetization. The measurements show that the resistance of the Fe-Ni-B system against neutron irradiation improves with increasing Ni content up to a certain point.

Moessbauer spectroscopy. Tutorial book

International Nuclear Information System (INIS)

Yoshida, Yutaka; Langouche, Guido

2013-01-01

First textbook on Moessbauer Spectroscopy covering the complete field. Offers a concise introduction to all aspects of Moessbauer spectroscopy by the leading experts in the field. Tutorials on Moessbauer Spectroscopy. Since the discovery of the Moessbauer Effect many excellent books have been published for researchers and for doctoral and master level students. However, there appears to be no textbook available for final year bachelor students, nor for people working in industry who have received only basic courses in classical mechanics, electromagnetism, quantum mechanics, chemistry and materials science. The challenge of this book is to give an introduction to Moessbauer Spectroscopy for this level. The ultimate goal of this book is to give this audience not only a scientific introduction to the technique, but also to demonstrate in an attractive way the power of Moessbauer Spectroscopy in many fields of science, in order to create interest among the readers in joining the community of Moessbauer spectroscopists. This is particularly important at times where in many Moessbauer laboratories succession is at stake.

Moessbauer investigations of itmid

Energy Technology Data Exchange (ETDEWEB)

Mrayed, Y S; Ellid, M S; Fallagh, F A [Physics and material Science Department, Tajoura Nuclear Research Center, Tripoli, (Libyan Arab Jamahiriya)

1997-12-31

A sample of itmid available commercially was obtained and investigated using{sup 57} Fe Moessbauer spectroscopy, atomic absorption, X-ray fluorescence. The Moessbauer spectra showed the presence hematite (alpha-Fe{sub 2} O{sub 3}), goethite (alpha-FeOOH), and a third phase which has a six-line spectrum with the following parameters : Isomer shift (gamma= 0.52 mm/s), magnetic field (H=290 kOe). After conducting a series of reduction and calcination to the itmid sample and with the aid of atomic absorption and X-ray fluorescence results the third phase was identified as the iron sulfide compound FeS. 3 figs., 3 tabs.

Moessbauer and XRD study of pulse plated Fe-P and Fe-Ni thin layers

International Nuclear Information System (INIS)

Miko, Annamaria; Kuzmann, Erno; Lakatos-Varsanyi, Magda; Kakay, Attila; Nagy, Ferenc; Varga, Lajos Karoly

2005-01-01

57 Fe conversion electron Moessbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe-P and Ni-Fe coatings. XRD and 57 Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe-P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe-P deposits pulse plated at medium long deposition time (t on = 2 ms), with short relaxation time (t off = 9 ms) and low current density (I p = 0.05 Acm -2 ) or at short deposition time (t on = 1 ms) with long relaxation time (t off = 250 ms) and high current density (I p = 1.0 Acm -2 ). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni-Fe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni-Fe and Fe-P pulse plated thin layers.

Moessbauer spectroscopy and X-ray diffraction studies of Fe-Ni order-disorder processes in a 35% Ni meteorite (Santa Catharina)

International Nuclear Information System (INIS)

Scorzelli, R.B.; Danon, J.

1985-01-01

The composition and structure of iron-nickel alloys in the Santa Catharina iron meteorite were investigated by metallographic techniques, electron microprobe analysis, Moessbauer spectroscopy and X-ray diffraction. The occurence of an ordered Fe-Ni phase with non-cubic symmetry is demonstrated. This phase is present in large proportions in the Santa Catharina meteorite, and has been identified by its asymmetric Moessbauer spectrum, arising from the presence of a quadrupolar splitting superposed on the magnetic hyperfine splitting. The other major Fe-Ni phase in Santa Catharina gives rise to a single line Moessbauer spectrum with no hyperfine components. X-ray diffraction confirms the presence of the Fe-Ni Llo superstructure in this meteorite. Lattice parameter variations with temperature were found to be identical for the meteorite and for electron irradiated Fe-Ni alloys of the sample composition. Detailed Moessbauer spectroscopy studies from room temperature to liquid helium, and in the presence of external magnetic field show the presence of a smaller amount of another ferromagnetic Fe-Ni phase, probably with disordered structure. The destruction of the superstructure in the Santa Catharina meteorite was investigated after heating the samples. Partial ordering seems to coexist with the disordered phase at intermediate annealing temperatures. At higher temperatures the samples are homogeneous and similar to laboratory produced Fe-Ni alloys with 35% Ni. Order-disorder transformations produced by shock waves and by mechanical treatment are also described. (orig.)

Assessment of the optimum degree of Sr{sub 3}Fe{sub 2}MoO{sub 9} electron-doping through oxygen removal: An X-ray powder diffraction and {sup 57}Fe Moessbauer spectroscopy study

Energy Technology Data Exchange (ETDEWEB)

Lopez, Carlos A.; Viola, Maria del C. [Area de Quimica General e Inorganica, Departamento de Quimica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina); Pedregosa, Jose C., E-mail: jpedreg@unsl.edu.ar [Area de Quimica General e Inorganica, Departamento de Quimica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina); Mercader, Roberto C., E-mail: mercader@fisica.unlp.edu.ar [Departamento de Fisica, IFLP-CONICET, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina)

2010-10-15

We describe the preparation and structural characterization by X-ray powder diffraction (XRPD) and Moessbauer spectroscopy of three electron-doped perovskites Sr{sub 3}Fe{sub 2}MoO{sub 9-{delta}} with Fe/Mo = 2 obtained from Sr{sub 3}Fe{sub 2}MoO{sub 9}. The compounds were synthesized by topotactic reduction with H{sub 2}/N{sub 2} (5/95) at 600, 700 and 800 {sup o}C. Above 800 {sup o}C the Fe/Mo ratio changes from Fe/Mo = 2-1 < Fe/Mo < 2. The structural refinements of the XRPD data for the reduced perovskites were carried out by the Rietveld profile analysis method. The crystal structure of these phases is cubic, space group Fm3-bar m, with cationic disorder at the two different B sites that can be populated in variable proportions by the Fe atoms. The Moessbauer spectra allowed determining the evolution of the different species formed after the treatments at different temperatures and confirm that Fe ions in the samples reduced at 600, 700 and 800 {sup o}C are only in the high-spin Fe{sup 3+} electronic state.

Moessbauer Spectroscopy Studies of Some Intermetallics in the Zr-Nb-Fe System

International Nuclear Information System (INIS)

Ramos, C.; Saragovi, C.; Granovsky, M.; Arias, D.

2002-01-01

Samples with the following compositions: Zr 62 Nb 14 Fe 24 , Zr 65 Nb 10 Fe 25 and Zr 52 Nb 10 Fe 38 were studied by Moessbauer spectroscopy. All of them showed a ternary cubic Ti 2 Ni-type phase (QS: 0.30±0.02, IS: -0.14±0.01) and traces of Zr 2 Fe phase (QS: 0.86±0.03, IS: -0.29±0.01). Zrβ phase (QS: 0.22±0.01, IS: -0.11±0.01) was also detected except in the case of the richer Fe sample. In addition to these expected phases, a hexagonal MgZn 2 -type phase was determined. The assigned parameters for this phase are: QS: 0.38±0.04, IS: -0.28±0.02. These results suggest a revision of the diagram.

Moessbauer study of iron uptake in cucumber root

Energy Technology Data Exchange (ETDEWEB)

Kovacs, K.; Kuzmann, E., E-mail: kuzmann@para.chem.elte.hu [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Fodor, F. [Eoetvoes Lorand University, Department of Plant Physiology and Molecular Plant Biology (Hungary); Vertes, A. [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Kamnev, A. A. [Russian Academy of Sciences, Institute of Biochemistry and Physiology of Plants and Microorganisms (Russian Federation)

2005-09-15

{sup 57}Fe Moessbauer spectroscopy was used to study the uptake and distribution of iron in the root of cucumber plants grown in iron-deficient modified Hoagland nutrient solution and put into iron-containing solution with 10 {mu}M Fe citrate enriched with {sup 57}Fe (90%) only before harvesting. The Moessbauer spectra of the frozen roots exhibited two Fe{sup 3+} components with typical average Moessbauer parameters of {delta} = 0.5 mm s{sup -1}, {Delta} = 0.46 mm s{sup -1} and {delta} = 0.5 mm s{sup -1}, {Delta} = 1.2 mm s{sup -1} at 78 K and the presence of an Fe{sup 2+} doublet, assigned to the ferrous hexaaqua complex. This finding gives a direct evidence for the existence of Fe{sup 2+} ions produced via root-associated reduction according to the mechanism proposed for iron uptake for dicotyledonous plants. Monotonous changes in the relative content of the components were found with the time period of iron supply. The Moessbauer results are interpreted in terms of iron uptake and transport through the cell wall and membranes.

The magnetic moment of NiO nanoparticles determined by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Bahl, C R H; Hansen, M F; Pedersen, T; Saadi, S; Nielsen, K H; Lebech, B; Moerup, S

2006-01-01

We have studied the magnetic properties of 57 Fe-doped NiO nanoparticles using Moessbauer spectroscopy and magnetization measurements. Two samples with different degrees of interparticle interaction were studied. In both samples the particles were characterized by high-resolution transmission electron microscopy and x-ray diffraction and found to be plate-shaped. Computer simulations showed that high-field Moessbauer data are very sensitive to the size of the uncompensated magnetic moment. From analyses of the Moessbauer spectra we have estimated that the size of the uncompensated magnetic moment is in accordance with a model based on random occupation of surface sites. The analyses of the magnetization data gave larger magnetic moments, but the difference can be explained by the different sensitivity of the two methods to a particle size distribution and by interactions between the particles, which may have a strong influence on the moments estimated from magnetization data

Study of reversible binding of molecular oxygen to cobalt(II) octaethylporphyrin by /sup 57/Co Moessbauer emission spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Sakai, H; Maeda, Y [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Ogoshi, H; Sugimoto, H; Yoshida, Z

1978-04-01

/sup 57/Co Moessbauer emission spectra of Co(II) octaethylporphyrin, Co(II) OEP, and its pyridine and oxygen adduct, Co(II) OEP.Py.O/sub 2/, have been measured in the dimethylformamide frozen solution at 20/sup 0/K. The former consists of two chemical species of Fe(II) OEP. The latter exhibits Fe(II) OEP.Py.O/sub 2/ and Fe(II) OEP.Py/sub 2/. The oxygenated complex is changed to the bis-pyridine adduct by evacuation at about -30/sup 0/C.

Moessbauer spectroscopy of the Zr-rich region in Zr-Nb-Fe alloys with low Nb content

International Nuclear Information System (INIS)

Ramos, C.; Saragovi, C.; Granovsky, M.; Arias, D.

1999-01-01

Intermetallic phases and solid solutions in the Zr-rich region of the Zr-Nb-Fe system with low Nb content are studied by Moessbauer spectroscopy complemented with X-ray diffraction, optical and scanning electron microscopy and electron microprobe analysis. The phases found in each sample were those expected from the corresponding binary Zr-Fe system. Furthermore, one of the samples showed a ternary cubic Ti 2 Ni type phase with a similar stoichiometry to the tetragonal Zr 2 Fe compound. Moessbauer parameters were suggested to this phase (IS: - 0.12 mm/s, QS: 0.30 mm/s), to the bcc Zr(β) phase (IS: (-0.11 α 0.01) mm/s, QS: (0.23 α 0.02) mm/s), and to the hcp Zr(β T ) phase (IS: (-0.24 α 0.02) mm/s, QS: (0.45 α 0.02) mm/s)

Moessbauer high pressure and magnetic field studies of the superconductor FeSe

Energy Technology Data Exchange (ETDEWEB)

Ksenofontov, Vadim; Felser, Claudia [Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, Mainz (Germany); Wortmann, Gerhard [Department of Physics, University of Paderborn, Paderborn (Germany); Trojan, Ivan; Palasyuk, Taras; Medvedev, Sergey; Eremets, Michail [Max-Planck-Institute for Chemistry, Mainz (Germany); McQueen, Tyrel M.; Cava, Richard J. [Department of Chemistry, Princeton University, Princeton (United States)

2010-07-01

Superconducting FeSe has been investigated by Moessbauer spectroscopy applying high pressure and strong external magnetic fields. It was found that pressure-induced structural phase transition between tetragonal and hexagonal modifications is accompanied by increased distortion of local surrounding of Fe atoms. Appearance of the hexagonal phase above 7.2 GPa is accompanied by degradation of superconducting properties of FeSe. Low-temperature measurements demonstrated that the ground states in both orthorhombic and hexagonal phases of FeSe are nonmagnetic. Moessbauer measurements in the external magnetic field below transition to the superconducting state revealed zero electron spin density on Fe atoms. Interpretation of Moessbauer spectra of FeSe in the Shubnikov phase is discussed.

Magnetism of DyMn2 and HoMn2 - 57Fe and 119Sn Moessbauer studies

International Nuclear Information System (INIS)

Krop, K.; Haeufler, T.; Hilscher, G.; Steiner, W.

1995-01-01

Moessbauer spectra were measured for two Laves phase compounds DyMn 2 and HoMn 2 in which manganese was substituted to 0.5% with 57 Fe and to 0.2% with 119 Sn. At 4.2 K the 57 Fe and 119 Sn spectra of the Dy compound were unambiguously fitted each with two Zeeman patterns (with relative contributions to the spectra 3:1) corresponding to two different Mn sites - magnetic and nonmagnetic. Transferred hyperfine fields at 119 Sn were found to be proportional to the magnetic moment of Dy and its ferromagnetic component, corroborating the magnetic structure found in neutron diffraction (ND) experiment. The same procedure was carried on with the spectra measured for the Ho compound, but the above mentioned proportionality was not found. ((orig.))

Formation of the 1:2:3 structure in Y-Ba-Cu(Fe)-O system studied by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Valko, P.; Miglierini, M.; Sitek, J.; Hucl, M.; Gruskova, A.

1990-01-01

Annealing time and temperature dependence of Y, Ba, Cu, Fe nitrade mixture towards new phases creation was revealed by Moessbauer spectroscopy. The observed changes can be assigned to chemical decomposition of corresponding nitrades and creation of intermedial and final Y 1 Ba 2 (Cu 0.95 Fe 0.05 ) 3 O x phase. (orig.)

Moessbauer Spectroscopy Studies of Some Intermetallics in the Zr-Nb-Fe System

Energy Technology Data Exchange (ETDEWEB)

Ramos, C. [CNEA-UNSAM, Comision Nacional de Energia Atomica, Instituto de Tecnologia J. Sabato (Argentina); Saragovi, C. [Comision Nacional de Energia Atomica, Departamento de Fisica (Argentina); Granovsky, M.; Arias, D. [Comision Nacional de Energia Atomica, Departamento de Materiales (Argentina)

2002-03-15

Samples with the following compositions: Zr{sub 62}Nb{sub 14}Fe{sub 24}, Zr{sub 65}Nb{sub 10}Fe{sub 25} and Zr{sub 52}Nb{sub 10}Fe{sub 38} were studied by Moessbauer spectroscopy. All of them showed a ternary cubic Ti{sub 2}Ni-type phase (QS: 0.30{+-}0.02, IS: -0.14{+-}0.01) and traces of Zr{sub 2}Fe phase (QS: 0.86{+-}0.03, IS: -0.29{+-}0.01). Zr{beta} phase (QS: 0.22{+-}0.01, IS: -0.11{+-}0.01) was also detected except in the case of the richer Fe sample. In addition to these expected phases, a hexagonal MgZn{sub 2}-type phase was determined. The assigned parameters for this phase are: QS: 0.38{+-}0.04, IS: -0.28{+-}0.02. These results suggest a revision of the diagram.

Selective Dissolution Techniques, X-Ray Diffraction and Moessbauer Spectroscopy Studies of Forms of Fe in Particle-Size Fractions of an Entic Haplustoll

International Nuclear Information System (INIS)

Acebal, S. G.; Aguirre, M. E.; Santamaria, R. M.; Mijovilovich, A.; Petrick, S.; Saragovi, C.

2003-01-01

Particle-size fractions (o = mean diameter, 5-2 μm, 2-1 μm, and 57 Fe Moessbauer spectroscopy (MS). Quartz, feldspar, smectite, illite and interstratified illite-smectite are the dominant minerals whereas Fe oxides and oxy-hydroxides are present in low concentration but increase as particle size decreases. Poorly crystallized oxides (highly Al-substituted hematite and goethite) amounts are lower, comparable to or slightly higher than the hematite amounts in the o 5-2 μm, 2-1 μm and 3+ and Fe 2+ are associated to the clay minerals and/or hydroxyl-interlayered 2:1 type material present; part of this Fe 3+ is located in the hydroxy-interlayers its amount being higher in the smallest fraction. Any possible changes after the PY and NaOH treatments were not detected by MS.

Moessbauer and XRD study of pulse plated Fe-P and Fe-Ni thin layers

Energy Technology Data Exchange (ETDEWEB)

Miko, Annamaria [Bay Zoltan Institute for Material Science (Hungary); Kuzmann, Erno, E-mail: kuzmann@para.chem.elte.hu [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Lakatos-Varsanyi, Magda [Bay Zoltan Institute for Material Science (Hungary); Kakay, Attila [Research Institute for Solid State Physics and Optics (Hungary); Nagy, Ferenc [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Varga, Lajos Karoly [Research Institute for Solid State Physics and Optics (Hungary)

2005-09-15

{sup 57}Fe conversion electron Moessbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe-P and Ni-Fe coatings. XRD and {sup 57}Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe-P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe-P deposits pulse plated at medium long deposition time (t{sub on} = 2 ms), with short relaxation time (t{sub off} = 9 ms) and low current density (I{sub p} = 0.05 Acm{sup -2}) or at short deposition time (t{sub on} = 1 ms) with long relaxation time (t{sub off} = 250 ms) and high current density (I{sub p} = 1.0 Acm{sup -2}). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni-Fe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni-Fe and Fe-P pulse plated thin layers.

Moessbauer spectroscopy of the Zr-rich region in Zr-Nb-Fe alloys with low Nb content

Energy Technology Data Exchange (ETDEWEB)

Ramos, C. [Universidad de Buenos, Facultad de Ciencias Exactas y Naturales (Argentina); Saragovi, C. [Departamento de Fisica, Comision Nacional de Energia Atomica (Argentina); Granovsky, M.; Arias, D. [Departamento de Materiales, Comision Nacional de Energia Atomica (Argentina)

1999-11-15

Intermetallic phases and solid solutions in the Zr-rich region of the Zr-Nb-Fe system with low Nb content are studied by Moessbauer spectroscopy complemented with X-ray diffraction, optical and scanning electron microscopy and electron microprobe analysis. The phases found in each sample were those expected from the corresponding binary Zr-Fe system. Furthermore, one of the samples showed a ternary cubic Ti{sub 2}Ni type phase with a similar stoichiometry to the tetragonal Zr{sub 2}Fe compound. Moessbauer parameters were suggested to this phase (IS: - 0.12 mm/s, QS: 0.30 mm/s), to the bcc Zr({beta}) phase (IS: (-0.11 {alpha} 0.01) mm/s, QS: (0.23 {alpha} 0.02) mm/s), and to the hcp Zr({beta}{sup T}) phase (IS: (-0.24 {alpha} 0.02) mm/s, QS: (0.45 {alpha} 0.02) mm/s)

A versatile gas-flow proportional counter for Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Bibicu, I., E-mail: bibicu@infim.ro [National Institute for Materials Physics (Romania); Nicolescu, G. [IFIN-HH, National Institute of Physics and Nuclear Engineering (Romania); Cretu, C. [Transylvania University, Physics Department (Romania)

2009-07-15

This article presents a versatile gas-flow proportional counter for surface and transmission Moessbauer spectroscopy, suitable for studies with {sup 57}Fe, {sup 119}Sn and {sup 151}Eu isotopes. The main advantages obtained by new design are: (1) the height of the detection volume can be changed in large limits from 0 to 38 mm, (2) the detection volume can be choose symmetrical or not in respect with anode plan, (3) the anode replacement is easily (4) and different anode configuration can be used. The characteristics of the detector, operating at room temperature, are reported.

Study of irradiated F82H steel and its model Fe-Cr alloy by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Huang, S.S.; Kitao, S.; Xu, Q.; Sato, K.; Yoshiie, T.

2013-01-01

In this work, Moessbauer spectroscopy which is a super-precision tool was conducted on F82H and its model Fe-Cr alloys before and after irradiation to take a further look on the interaction between carbides and point defects and Cr effect on microstructural evolution during irradiation in void incubation period. (J.P.N.)

Magnetic and thermal Moessbauer effect scans: a new approach

International Nuclear Information System (INIS)

Pasquevich, G. A.; Zelis, P. Mendoza; Sanchez, F. H.; Fernandez van Raap, M. B.; Veiga, A.; Martinez, N.

2006-01-01

Moessbauer transmission recorded at fixed photon energies as a function of a given physical parameter such as temperature, external field, etc. (Moessbauer scan), is being developed as a useful quantitative tool, complementary of Moessbauer spectroscopy. Scans are performed at selected energies, suitable for the observation of a given physical property or process. It is shown that one of main advantages of this approach is the higher speed at which the external physical parameter can be swept, which allows the recording of quasi-continuous experimental response functions as well as the study of processes which occur too fast to be followed by Moessbauer spectroscopy. The applications presented here are the determination of the temperature dependence of the 57 Fe hyperfine field in FeSn 2 , the thermal evolution and nanocrystallization kinetics of amorphous Fe 73.5 Si 13.5 Cu 1 Nb 3 B 9 and the measurement of the dynamic response of Fe magnetic moments in nanocrystalline Fe 90 Zr 7 B 3 to an external ac field.

Spin ordering in LaFeAsO and its suppression in superconductor LaFeAsO0.89F0.11 probed by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Kitao, Shinji; Kobayashi, Yasuhiro; Higashitaniguchi, Satoshi; Saito, Makina; Seto, Makoto; Kamihara, Yoichi; Hirano, Masahiro; Hosono, Hideo; Mitsui, Takaya

2008-01-01

57 Fe Moessbauer spectroscopy was applied to an iron-based layered superconductor LaFeAsO 0.89 F 0.11 with a transition temperature of 26 K and to its parent material LaFeAsO. Throughout the temperature range from 4.2 to 298 K, a singlet pattern with no magnetic splitting was observed in the Moessbauer spectrum of the F-doped superconductor. Furthermore, no additional internal magnetic field was observed for the spectrum measured at 4.2 K under a magnetic field of 7 T. On the other hand, magnetically split spectra were observed in the parent LaFeAsO below 140 K, and this temperature is slightly lower than that of a structural phase transition from tetragonal to orthorhombic phase, which accompanies the electrical resistivity anomaly at around 150 K. The magnetic moment is estimated to be ∼0.35 μ B /Fe from the internal magnetic field of 5.3 T at 4.2 K in the orthorhombic phase, and the spin disorder appears to remain in the magnetically ordered state even at 4.2 K. The lack of a magnetic transition in LaFeAsO 0.89 F 0.11 down to 4.2 K suggests that this system exhibits a paramagnetic state or that the magnetic moment is small. The present results show that F doping effectively suppresses the magnetic and structural transitions in the parent material, leading to the emergence of superconductivity in the F-doped system. (author)

DyNi{sub 2}Mn-magnetisation and Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Wang Jianli; Campbell, Stewart James, E-mail: stewart.campbell@adfa.edu.au [University of New South Wales, School of Physical, Environmental and Mathematical Sciences (Australia); Kennedy, Shane Joseph [ANSTO, Bragg Institute (Australia); Dou Shixue [University of Wollongong, Institute for Superconductivity and Electronic Materials (Australia); Wu Guangheng [Chinese Academy of Science, Institute of Physics (China)

2012-03-15

The physical properties of DyNi{sub 2}Mn doped with {sup 57}Fe have been investigated by X-ray diffraction, magnetisation (10-300 K) and {sup 57}Fe Moessbauer spectroscopy measurements (5-300 K). DyNi{sub 2}Mn({sup 57}Fe) crystallizes in the MgCu{sub 2}-type cubic structure (Fd{sup }-3m space group). The ordering temperature is found to be T{sub C} = 99(2) K, much higher than those of DyNi{sub 2} ({approx}22 K) and DyMn{sub 2} ({approx}35 K). Analyses of isothermal M-H curves and the related Arrott plots confirm that the magnetic phase transition at T{sub C} is second order. The magnetic entropy change around T{sub C} is 4.0 J/kg K for a magnetic field change of 0 T to 5 T. The spectra above T{sub C} exhibit features consistent with quadrupolar effects while below T{sub C} the spectra exhibit magnetic hyperfine splitting. The Debye temperature for DyNi{sub 2}Mn has been determined as {theta}{sub D} = 200(20) K from a fit to the variable temperature isomer shift IS(T).

Corrosion of steam generator pipelines analysed using Moessbauer spectroscopy

International Nuclear Information System (INIS)

Slugen, V.; Lipka, J.; Toth, I.; Hascik, J.; Hinca, R.; Lehota, M.

2003-01-01

The variability of the properties and the composition of the corrosion products of the stainless CrNi and mild steels in dependence on the conditions (temperature, acidity, etc.) is of such range that, in practice, it is impossible to determine the properties of the corrosion products for an actual case from the theoretical data only. Since the decontamination processes for the materials of the water-cooled reactor (VVER-440) secondary circuits are in the progress of development, it is necessary to draw the needed information by the measurement and analysis of the real specimens. The corrosion layers was separated by scraping the rust off the surface and the powder samples were studied by transmission Moessbauer spectroscopy. It should be noted that the gamma spectroscopic measurements give no evidence of the presence of low-energy gamma radiation emitted from the samples. The scraped specimen powder was homogenised (using a 50 μm sieve) and fixed into a special holder. The 57 Co in Rh matrix was used as the radioactive Moessbauer source. Measured spectra were fitted using program NORMOS SITE. According to the results obtained from Moessbauer spectra, it is possible to establish that the main component of secondary circuit's corrosion products is magnetite Fe 3 O 4 . Next components are hematite α-Fe 2 O 3 and hydroxide akagenite β-FeOOH, which is characterised by significant paramagnetic doublet in the middle of spectra. The sextets corresponding to base materials (martensite and austenite steels) were identified in all measured spectra. (author)

Moessbauer study of hydrated iron sulfates

International Nuclear Information System (INIS)

Araujo, S.I.; Danon, J.; Iannarella, L.

1991-01-01

The hydrated iron sulfates amarantite Fe(SO sub(4))(OH).3H sub(2)O, copiapite (Mg,Al)Fe sup(3+) sub(4)(SO sub(4)) sub(6)(OH) sub(2).20H sub(2)O and ungemachite K sub(3)Na sub(9)Fe(SO sub(4)) sub(6)(OH) sub(3).9H sub(2)O were studied by Moessbauer Spectroscopy (MS) in connection with Differential Scanning Calorimetry (DSC). The effect of the dehydration on the hyperfine parameters at the Fe sites was investigated. For amarantite, the Moessbauer spectrum remained practically unchanged, while the Fe sup(3+) quadrupole splittings for copiapite and ungemachite increased. The Fe sup(2+) quadrupole splitting of ungemachite was also unchanged. We have found out the anisotropy of the recoiless absorption probability for the sup(57)Fe Moessbauer gamma ray in amarantite. The three minerals were found to be highly hygroscopic after the dehydration consequent of the DSC measurements. (author)

Moessbauer Investigation of Spin Arrangements in Er2-xCexFe14B

International Nuclear Information System (INIS)

Bogacz, B.F.; Pedziwiatr, A.T.

2008-01-01

It was theoretically postulated earlier that in compounds Er 2-x Ce x Fe 14 B it may be possible to observe not only axial and planar spin arrangements but also a conical one. In order to experimentally verify this hypothesis, 57 Fe Moessbauer spectroscopy analysis was used to study the polycrystalline compounds Er 2-x Ce x Fe 14 B in the postulated composition region (x = 1.0, 1.1, 1.2, 1.3) in the wide range of temperatures. The obtained experimental data do not clearly support the suggestion of conical arrangement occurrence in the postulated compositions. They indicate that such phenomenon may be shifted towards higher Ce content. (authors)

Trace cobalt speciation in bacteria and at enzymic active sites using emission Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Kamnev, A.A.; Antonyuk, L.P.; Smirnova, V.E.; Serebrennikova, O.B. [Laboratory of Biochemistry, Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Saratov (Russian Federation); Kulikov, L.A.; Perfiliev, Yu.D. [Laboratory of Nuclear Chemistry Techniques, Department of Radiochemistry, Faculty of Chemistry, Moscow State University (Russian Federation)

2002-02-01

{sup 57}Co emission Moessbauer spectroscopy (EMS) allows the chemical state of cobalt, as influenced by its coordination environment, to be monitored in biological samples at its physiological (trace) concentrations. To draw attention to EMS as a valuable tool for speciation of cobalt in biocomplexes, the process of cobalt(II) metabolism in cells of the plant growth-promoting rhizobacterium Azospirillum brasilense Sp245 was investigated using EMS of {sup 57}Co{sup II}-doped bacterial cells. EMS measurements also showed {sup 57}Co{sup II}-activated glutamine synthetase (GS, a key enzyme of nitrogen metabolism, isolated from this bacterium) to have two different cobalt(II) forms at its active sites, in agreement with data available on other bacterial GSs. Chemical after-effects following electron capture by the nucleus of the parent {sup 57}Co{sup II} during the {sup 57}Co{yields}{sup 57}Fe transition, which contribute to the formation of a stabilised daughter {sup 57}Fe{sup III} component along with the nucleogenic {sup 57}Fe{sup II} forms, are also briefly considered. (orig.)

Diffusion of iron in β-iron telluride (Fe1.12Te) by Moessbauer spectroscopy and tracer method

International Nuclear Information System (INIS)

Magara, Masaaki; Tsuji, Toshihide; Naito, Keiji

1993-01-01

The diffusion coefficient of iron in a β-iron telluride (Fe 1.12 Te) polycrystalline sample was measured by Moessbauer diffusional line broadening method which relates to the collapse of coherence in gamma-ray photon by the atomic jump at local sites. The diffusion coefficient of iron along the c-axis in nearly single crystal of β-iron telluride was also measured by tracer technique which shows the results of an atom transport in long distance. The activation energies for the diffusion of iron in Fe 1.12 Te obtained by the Moessbauer spectroscopy and the tracer method were 91.5±5.4 and 106±23 kJ/mol, respectively. The diffusion coefficients of iron in β-iron telluride obtained by Moessbauer line broadening are in fair agreement with the values averaged from that along c-axis obtained by tracer method and that along a- and b-axes obtained from reaction rate constant between iron and tellurium by the previous study of the present authors. (orig.)

Moessbauer spectroscopy in nanocrystalline Fe88Zr7B4Cu1

International Nuclear Information System (INIS)

Navarro, I.

1995-01-01

Local structural changes during the crystallization process of initially amorphous Fe 88 Zr 7 B 4 Cu 1 (at %) have been investigated by means of Moessbauer spectroscopy at room temperature. In the as-cast state, no ferromagnetic phase has been detected. The crystallization process has been found to consist of two steps. In the first step (after annealing up to 500-650 C), precipitation of α-Fe (47-59%) takes place. The remaining amorphous matrix evolves to a ferromagnetic phase, although a small fraction of non-ferromagnetic phase (5-8%) is also detected during the crystallization process. Annealing at more elevated temperatures completely crystallizes the amorphous phase and three new crystalline subspectra are found. Correlations between the soft magnetic properties and these local structural changes are also discussed. ((orig.))

Sorption-induced reversible oxidation of Fe(2) at the smectite/water interface under strictly anoxic conditions. A Moessbauer spectroscopy study

Energy Technology Data Exchange (ETDEWEB)

Gehin, A.; Charlet, L. [Laboratoire de Geophysique Interne et Tectonophysique (LGIT), Universite de Grenoble, 38 - Grenoble (France); Gehin, A. [Agence Nationale pour la Gestion des Dechets Radioactifs, ANDRA, 92 - Chatenay Malabry (France); Greneche, J.M. [Laboratoire de Physique de l' Etat Condense, UMR-CNRS 6087, 72 - Le Mans (France); Brendle, J. [Universite de Haute Alsace, Lab. des Materiaux Mineraux (LMM), 68 - Mulhouse (France); Rancourt, D.G. [Ottawa Univ., Dept. of Physics, Ontario (Canada)

2005-07-01

Previous studies of Fe(II) sorption onto montmorillonite have been performed with the mineral extracted from the MX80 bentonite. These studies have shown that Fe(II) can be sorbed onto clay minerals in cation exchange position. The affinity of montmorillonite for Fe(II) and Ca(II) is identical. Fe(II) may also be specifically adsorbed onto montmorillonite clay edges. Moessbauer spectroscopy confirmed the high affinity of clay surfaces for Fe(II) sorption and showed that this sorption is mainly due to a two step mechanism: Fe(II) specific adsorption, followed by oxidation of the Fe(II) sorbed. The identification of the oxidizing agent was prohibited due to the complex chemistry of the natural MX80 montmorillonite. Thus, synthetic iron-free montmorillonite was used (chemical formula: Ca{sub 0.3} (A{sub 1.4}Mg{sub 0.6}) (Si{sub 4}) O{sub 10}(OH){sub 2} ). {sup 57}Fe(II) sorption experiments were conducted in a N{sub 2} atmosphere gloves-box, in strictly anoxic conditions. Solid samples were synthesized in order to confirm the clay high affinity for Fe(II), in absence of structural oxidant, and to have a better comprehension of the sorption mechanism. Moessbauer spectra were recorded for each sample. Whereas no Fe(III) is detected in solution as pH was increased and then, a significant amount of surface sorbed Fe(III) was found to be reversibly produced, which amounts for 0-3% of total Fe in the pre-sorption edge acid region, up to 7% of total Fe when all Fe is sorbed in the neutral to alkaline pH range. From pH {approx_equal} 2 to pH {approx_equal} 7, a sorption edge plateau is observed. In this plateau, the sorbed-Fe(III)/sorbed-Fe ratio increases with pH, up to 45% at pH 7. Moessbauer spectra comparison with ferrous hydroxide, synthesized in the same redox conditions at higher pH, show that this oxidation can not be due to the trace amounts Oz in the suspension. The Moessbauer spectra components of both Fe(II) and Fe(III) appears as paramagnetic doublets: iron has

Structural Relaxation in Fe78Nb2B20 Amorphous Alloy Studied by Moessbauer Spectroscopy

International Nuclear Information System (INIS)

Kansy, J.; Hanc, A.; Rasek, J.; Haneczok, G.; Pajak, L.; Stoklosa, Z.; Kwapulinski, P.

2011-01-01

It was shown that soft magnetic properties of Fe 78 Nb 2 B 20 amorphous alloy can be significantly improved by applying 1-h annealing at temperature 623 K (permeability increases even about 8 times). The Moessbauer Spectroscopy technique indicated that the optimized microstructure (corresponding to the maximum magnetic permeability) is free of iron nanograins and should be attributed to annealing out of free volume and a reduction of internal stresses i.e. to the relaxed amorphous phase. (authors)

A methodological proposal for ancient kiln simulation analyzed by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Flores, E.; Fernandes, B.; Flores, E.; Fernandez, B.

1988-01-01

In previous papers scientistis from different countries have reported simulating incomplete methodologies for ancient kiln firing conditions. Results from clays fired in a first working hypothesis are presented to end as a methodological proposal for simulation. This study was done through Moessbauer spectroscopy. The fired clay used presented a Fe 2+ and Fe 3+ spectrum in octahedric sites. Moessbauer parameters complemented by other studies indicate illite is the predominant clay mineral. A trait of the parameters behaviour in presence of temperature is reported. (author)

Moessbauer spectroscopy as a tool in astrobiology

Energy Technology Data Exchange (ETDEWEB)

Schroeder, Christian, E-mail: schroedc@uni-mainz.de; Klingelhoefer, Goestar, E-mail: klingel@mail.uni-mainz.de [Johannes Gutenberg-Universitaet, Institut fuer Anorganische Chemie und Analytische Chemie (Germany); Bailey, Brad E., E-mail: bebailey@ucsd.edu; Staudigel, Hubert, E-mail: hstaudigel@ucsd.edu [University of California San Diego, Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography (United States)

2005-11-15

Two miniaturized Moessbauer spectrometers are part of the Athena instrument package of the NASA Mars Exploration Rovers, Spirit and Opportunity. The primary objectives of their science investigation are to explore two sites on the surface of Mars where water may once have been present, and to assess past environmental conditions at those sites and their suitability for life. Aqueous minerals - jarosite at Meridiani Planum, Opportunity's landing site, and goethite in the Columbia Hills in Gusev Crater, Spirit's landing site - were identified by Moessbauer spectroscopy, thus providing in situ proof of water being present at those sites in the past. The formation of jarosite in particular puts strong constraints on environmental conditions during the time of formation and hence on the evaluation of potential habitability. On Earth Moessbauer spectroscopy was used to investigate microbially induced changes in Fe oxidation states and mineralogy at the Loihi deep sea mount, a hydrothermal vent system, which might serve as an analogue for potential habitats in the Martian subsurface and the sub-ice ocean of Jupiter's icy moon Europa.

Moessbauer spectroscopy as a tool in astrobiology

International Nuclear Information System (INIS)

Schroeder, Christian; Klingelhoefer, Goestar; Bailey, Brad E.; Staudigel, Hubert

2005-01-01

Two miniaturized Moessbauer spectrometers are part of the Athena instrument package of the NASA Mars Exploration Rovers, Spirit and Opportunity. The primary objectives of their science investigation are to explore two sites on the surface of Mars where water may once have been present, and to assess past environmental conditions at those sites and their suitability for life. Aqueous minerals - jarosite at Meridiani Planum, Opportunity's landing site, and goethite in the Columbia Hills in Gusev Crater, Spirit's landing site - were identified by Moessbauer spectroscopy, thus providing in situ proof of water being present at those sites in the past. The formation of jarosite in particular puts strong constraints on environmental conditions during the time of formation and hence on the evaluation of potential habitability. On Earth Moessbauer spectroscopy was used to investigate microbially induced changes in Fe oxidation states and mineralogy at the Loihi deep sea mount, a hydrothermal vent system, which might serve as an analogue for potential habitats in the Martian subsurface and the sub-ice ocean of Jupiter's icy moon Europa.

Local structure of 57Mn/57Fe implanted into lithium hydride

International Nuclear Information System (INIS)

Miyazaki, Jun; Nagatomo, Takashi; Kobayashi, Yoshio

2013-01-01

We report the in-beam Moessbauer Spectra of 57 Mn implanted into polycrystalline LiH at under room temperature. As compared with the result of DFT calculations, 57 Fe atoms were implanted into Li or H substitutional site in LiH crystal. With an increase the sample temperature, we could observe the decrease of lattice defects. (author)

Moessbauer study of Fe-Co nanowires

Energy Technology Data Exchange (ETDEWEB)

Chen Ziyu [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou (China)]. E-mail: chenzy@lzu.edu.cn; Zhan Qingfeng; Xue Desheng; Li Fashen [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou (China); Zhou Xuezhi; Kunkel, Henry; Williams, Gwyn [Department of Physics and Astronomy, the University of Manitoba (Canada)

2002-01-28

Arrays of Fe{sub 1-x}Co{sub x} (0.0{<=}x{<=}0.92) nanowires have been prepared by an electrochemical process, co-depositing Fe and Co atoms into the pores of anodic aluminium; their compositions were determined by atomic absorption spectroscopy. Transmission electron microscope results show that the nanowires are regularly spaced and uniform in shape with lengths of about 7.5 {mu}m and diameters of 20 nm. The x-ray diffraction indicates a texture in the deposited nanowires. For the composition below 82 at.% cobalt, the nanowires had a body-centred-cubic structure with a [110] preferred orientation. For the 92 at.% cobalt sample, the alloy exhibited a mixture of bcc and face-centred-cubic structure. The room temperature {sup 57}Fe Moessbauer spectra of the arrays of Fe{sub 1-x}Co{sub x} nanowires have second and fifth absorption lines of the six-line pattern with almost zero intensity, indicating that the internal magnetic field in the nanowires lies along the long axis of the nanowire. The maximum values of the hyperfine field (B{sub hf} 36.6{+-}0.1 T) and isomer shift (IS=0.06{+-}0.01 mm s-1) occur for 44 at.% cobalt. The variations of the isomer shift and the linewidths with composition indicate that the Fe{sub 1-x}Co{sub x} alloy nanowires around the equiatomic composition are in an atomistic disordered state. (author)

Iron oxides characterization by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Basurto Sanchez, R.

1993-01-01

In this work rust development on low carbon wire surface after the conformation process at different temperatures was studied by Moessbauer spectroscopy. The characterization was made by determining the following spectral parameters; 1) Quadrupole splitting, 2) Isomer shift, and 3) Magnetic splitting. The area quantification determined the percentage amount of three different iron oxides. These iron oxides were: a) Wustite (Fe O), b) Hematite (Fe 2 O 3 ), and c) Magnetite (Fe 3 O 4 ) which were present in the rust studied. With the results it was possible to establish the best temperature to favor the development of each of these iron oxides. (Author)

Study of electron transmission through thin metallic films by the electron moessbauer spectroscopy

International Nuclear Information System (INIS)

Babikova, Yu.F.; Vakar, O.M.; Gruzin, O.M.; Petrikin, Yu.V.

1983-01-01

Results of the experimental study of the transmission of conversion electrons through aluminium, iron, tin and gold films are presented. Absorption of resonance electrons of the Moessbauer nuclide 57 Fe, formed during target irradiation with γ-quanta of 57 Co source in chromium matrix has been studied. It is asserted that absorption of conversion electrons in films of different elements is similar; at that, like in the case of β-particles, the law of absorption of resonance electrons, emitted from the flat layer, is exponential For conversion electrons of the Moessbauer nuclide 57 Fe the absorption coefficient is (0.025+-0.002) cm 2 /μg, which in the case of iron absorbing film corresponds to (20.0+-1.0)x10 4 cm -1

Evaluation the homogenisation behaviour of Sm-Fe-Nb materials by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Sinan, S. A.; Muryaed, Y.; Alhweg, F. A.

2004-01-01

The microstructure of cast and annealed Sm-Fe-Nb materials were investigated by Moessbauer spectroscopy. The aim of the present work is to study the effect of Nb additions upon the microstructure of Sm 2 Fe 17 material and evaluation the homogenisation behaviour of different Sm-Fe-Nb materials. The niobium free cast material consisting of the Sm 2 Fe 17 phase and significant amounts of the free iron (α -Fe). Therefore, the homogenisation process is necessary to eliminate the free iron and produce a single Sm 2 Fe 17 phase material. This process takes long annealing time, up to seven days. The Sm 9 .5 Fe 8 7.5 Nb 3 alloy contains the lowest amount of α-Fe among, the Sm-Fe-Nb materials. Thus the homogenisation step was carried out with treatment time (12 hours) smaller than the reported annealing time of Nb-free material (Sm 2 Fe 17 ). Therefore, the addition of at 3% Nb reduces the manufacturing cost of the Sm 2 Fe 17 and makes this based material for permanent magnets, more industrially desirable, due to elimination the free iron with lowest treatment time. Also it was found that the existence of the paramagnetic NbFe 2 phase becomes higher after the homogenisation process, which can be explained due to the diffusion of Nb from Sm 2 Fe 17 phase to paramagnetic NbFe 2 phase, during the annealing process. (authors)

Moessbauer studies of magnetic Fe2O3/SiO2 nanocomposite

International Nuclear Information System (INIS)

Lancok, A.; Zaveta, K.; Savii, C.; Barcova, K.

2006-01-01

Fe 2 O 3 /SiO 2 magnetic nanocomposites rich in Fe 2 O 3 have been obtained by annealing at 1000 grad C the xerogel samples, prepared under various conditions. The target concentrations of iron oxide in inert matrix were 20% and 30%. As mesoporous matrices both silica and polyvinyl alcohol - silica hybrid ones were used. The xerogel nanocomposite samples were obtained in situ and by impregnation under ultrasonic activation. All obtained samples were annealed under moderate oxidation conditions (air) and inert atmosphere such as vacuum or nitrogen. Moessbauer spectra were obtained using a conventional Moessbauer spectrometer with a 57 Co/Rh source and constant acceleration. Velocity calibration was done using α-iron, and the Moessbauer parameters are given relative to this standard at room temperature. The Moessbauer spectra contained the sextets of ε-Fe 2 O 3 , hematite, and superparamagnetic component. The content of various phases in the samples depends on the conditions of preparation. In one of the samples also magnetite was present. The ranges of the ε-Fe 2 O 3 area of the samples are 39-76%. The hematite phase is only residual, after transformation due to heat treatment. (authors)

Moessbauer Spectroscopic Study of a Mural Painting from Morgadal Grande, Mexico

International Nuclear Information System (INIS)

Kuno, A.; Matsuo, M.; Soto, A. Pascual; Tsukamoto, K.

2004-01-01

In this study, 57 Fe Moessbauer spectroscopy has been applied to fragments of a mural painting excavated at Morgadal Grande, Mexico, to characterize the pigments used. A sextet attributable to hematite (α-Fe 2 O 3 ) was clearly detected in the red fragments. The spectra of orange fragments showed a doublet attributable to paramagnetic high-spin Fe 3+ , which presumably originates from goethite (α-FeOOH) exhibiting superparamagnetic relaxation due to its small particle size. The blue fragments contained little iron. The scattered X-ray Moessbauer spectra revealed that the thickness of the pigments was larger than 20 μm.

Moessbauer spectroscopy

International Nuclear Information System (INIS)

Zemcik, T.

1984-01-01

The emission and absorption of photons taking place without changes in the frequency spectrum of the crystal lattice are known as the Moessbauer effect. It takes place in the low energy levels of heavy nuclei in solid lattices at low temperatures. On the basis of the hyperfine structure of Moessbauer spectra the notions are explained of isomer shift, quadrupole splitting and magnetic splitting. The principle and function are explained of Moessbauer spectrometers and the methods of graphical processing of spectra, also the use of the least square fit. Moessbauer spectroscopy is nondestructive, highly sensitive and selective and makes structural resolution possible. It is used for quantitative and qualitative analysis of compounds. Examples are given of the use of this method for mineralogical and crystallo-chemical analysis of lunar minerals and rocks, for analysis of corrosion products of iron and for phase analysis of alloys. (M.D.)

Spin density wave in (Fe{sub x}V{sub 3-x})S{sub 4} and the coexistence of normal and condensate states: A Moessbauer study

Energy Technology Data Exchange (ETDEWEB)

Embaid, B.P., E-mail: pembaid@fisica.ciens.ucv.ve [Laboratorio de Magnetismo, Escuela de Fisica, Universidad Central de Venezuela, Apartado 47586, Los Chaguaramos, Caracas 1041-A (Venezuela, Bolivarian Republic of); Gonzalez-Jimenez, F. [Laboratorio de Magnetismo, Escuela de Fisica, Universidad Central de Venezuela, Apartado 47586, Los Chaguaramos, Caracas 1041-A (Venezuela, Bolivarian Republic of)

2013-03-15

Iron-vanadium sulfides of the monoclinic system Fe{sub x}V{sub 3-x}S{sub 4} (1.0{<=}x{<=}2.0) have been investigated by {sup 57}Fe Moessbauer Spectroscopy in the temperature range 30-300 K. Incommensurate spin density waves (SDW) have been found in this system. An alternative treatment of the spectra allows a direct measurement of the temperature evolution of condensate density of the SDW state which follows the Maki-Virosztek formula. For composition (x=1.0) the SDW condensate is unpinned while for compositions (x>1.0) the SDW condensate is pinned. Possible causes of the pinning-unpinning SDW will be discussed. - Highlights: Black-Right-Pointing-Pointer Fe{sub x}V{sub 3-x}S{sub 4}(1.0{<=}x{<=}2.0) system was investigated by {sup 57}Fe Moessbauer Spectroscopy. Black-Right-Pointing-Pointer Incommensurate spin density wave (SDW) has been found in this system. Black-Right-Pointing-Pointer We report the temperature evolution of the condensate density of SDW state. Black-Right-Pointing-Pointer For composition (x=1.0) the SDW is unpinned while for (x>1.0) is pinned.

Variations of {sup 57}Fe hyperfine parameters in medicaments containing ferrous fumarate and ferrous sulfate

Energy Technology Data Exchange (ETDEWEB)

Oshtrakh, M. I., E-mail: oshtrakh@mail.utnet.ru; Novikov, E. G. [Ural Federal University (The former Ural State Technical University-UPI), Faculty of Physical Techniques and Devices for Quality Control (Russian Federation); Dubiel, S. M. [AGH University of Science and Technology, Faculty of Physics and Computer Science (Poland); Semionkin, V. A. [Ural Federal University (The former Ural State Technical University-UPI), Faculty of Physical Techniques and Devices for Quality Control (Russian Federation)

2010-04-15

Several commercially available medicaments containing ferrous fumarate (FeC{sub 4}H{sub 2}O{sub 4}) and ferrous sulfate (FeSO{sub 4}), as a source of ferrous iron, were studied using a high velocity resolution Moessbauer spectroscopy. A comparison of the {sup 57}Fe hyperfine parameters revealed small variations for the main components in both medicaments indicating some differences in the ferrous fumarates and ferrous sulfates. It was also found that all spectra contained additional minor components probably related to ferrous and ferric impurities or to partially modified main components.

The Moessbauer effect in Fe(III) HEDTA, Fe(III) EDTA, and Fe(III) CDTA compounds

International Nuclear Information System (INIS)

Prado, F.R.

1989-01-01

The dependence of Moessbauer spectra with pH value of Fe(III)HEDTA and Fe(III)CDTA compounds is studied. Informations on formation processes of LFe-O-FeL (L=ligand) type dimers by the relation of titration curves of Fe(III)EDTA, Fe(III)HEDTA and Fe(III)CDTA compounds with the series of Moessbauer spectra, are obtained. Some informations on Fe-O-Fe bond structure are also obtained. Comparing the titration curves with the series of Moessbauer spectra, it is concluded that the dimerization process begins when a specie of the form FeXOH α (X = EDTA, HEDTA, CDTA; α = -1, -2) arises. (M.C.K.) [pt

57Fe Moessbauer Spectroscopy Studies of Meteorites: Implications for Weathering Rates, Meteorite Flux, and Early Solar System Processes

International Nuclear Information System (INIS)

Bland, P. A.; Berry, F. J.; Jull, A. J. T.; Smith, T. B.; Bevan, A. W. R.; Cadogan, J. M.; Sexton, A. S.; Franchi, L. A.; Pillinger, C. T.

2002-01-01

Ordinary chondrite finds, terrestrial age dated using 14 C analyses, from different meteorite accumulation sites, have been examined by Moessbauer spectroscopy to quantitatively determine terrestrial oxidation. We observe differences in weathering rates between sites, and also between different chondrite groups. A comparison of weathering over time, and its effect in 'eroding' meteorites, together with the number and mass distribution of meteorites in each region, enables us to derive estimates of the number of meteorite falls over a given mass per year. Studies of how the oxygen isotopic composition of samples varies with weathering indicate that incipient alteration may occur without a pronounced isotopic effect, possibly due to weathering of silicates to topotactically oriented smectite confined spaces where the water volume is limited. This finding has profound implications for the use of oxygen isotopes as a tool in understanding water-rock interaction. It also may reconcile previously contradictory data regarding the nebular or asteroidal location of pre-terrestrial aqueous alteration. Finally, Moessbauer spectroscopy is also found to be a useful tool in determining mineral abundance in carbonaceous chondrites, where a fine-grained matrix makes traditional approaches inapplicable. Again, the results have implications for the modification of chondritic materials in the early solar system.

Moessbauer study of proton-exchanged LiNbO3:Fe

International Nuclear Information System (INIS)

Engelmann, H.; Andler, G.; Dezsi, I.

1990-01-01

Topotactic proton exchange (Li against H) can be achieved by treating LiBnO 3 with appropriate acids. In order to investigate the effect of proton exchange on Fe-impurities we studied LiNbO 3 :Fe powder material treated in sulphuric acid and LiNbO 3 :Fe single crystals treated in benzoic acid by Moessbauer spectroscopy. During the topotactic ion exchange only the Li-ions are exchanged for protons, whereas the Fe-impurities are retained in the material. (orig.)

Magnetism of DyMn{sub 2} and HoMn{sub 2} - {sup 57}Fe and {sup 119}Sn Moessbauer studies

Energy Technology Data Exchange (ETDEWEB)

Krop, K. [University of Min. and Metall., Krakow (Poland). Dept. of Solid State Phys.; Zukrowski, J. [University of Min. and Metall., Krakow (Poland). Dept. of Solid State Phys.; Przewoznik, J. [University of Min. and Metall., Krakow (Poland). Dept. of Solid State Phys.; Marzec, J. [University of Min. and Metall., Krakow (Poland). Dept. of Solid State Phys.; Wiesinger, G. [Institute for Experimental Physics, Technical University, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Haeufler, T. [Institute for Experimental Physics, Technical University, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Hilscher, G. [Institute for Experimental Physics, Technical University, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Steiner, W. [Institute for Applied and Technical Physics, Technical University, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria)

1995-05-01

Moessbauer spectra were measured for two Laves phase compounds DyMn{sub 2} and HoMn{sub 2} in which manganese was substituted to 0.5% with {sup 57}Fe and to 0.2% with {sup 119}Sn. At 4.2 K the {sup 57}Fe and {sup 119}Sn spectra of the Dy compound were unambiguously fitted each with two Zeeman patterns (with relative contributions to the spectra 3:1) corresponding to two different Mn sites - magnetic and nonmagnetic. Transferred hyperfine fields at {sup 119}Sn were found to be proportional to the magnetic moment of Dy and its ferromagnetic component, corroborating the magnetic structure found in neutron diffraction (ND) experiment. The same procedure was carried on with the spectra measured for the Ho compound, but the above mentioned proportionality was not found. ((orig.)).

Study of a low alloy steel rust using Moessbauer spectroscopy

International Nuclear Information System (INIS)

Maier, I.A.; Saragovi-Badler, C.; Labenski, F.

1978-01-01

Moessbauer spectroscopy has been used to analyze the internal and external rust layers of a weathering steel exposed for ten months to an urban-industrial atmosphere. Superparamagnetic α-FeOOH and γ-FeOOH were found in both layers. The external one also contained small sized delta-FeOOH and/or amorphous iron oxyhydroxide. These compounds were not present in the internal layer at this stage of the patina formation. (author)

Moessbauer spectroscopy study of the synthesis of SnFe2O4 by high energy ball milling (HEBM) of SnO and α-Fe2O3

International Nuclear Information System (INIS)

Uwakweh, Oswald N C; Perez Moyet, Richard; Mas, Rita; Morales, Carolyn; Vargas, Pedro; Silva, Josue; Rossa, Angel; Lopez, Neshma

2010-01-01

The formation of single phase nanoparticles of spinel structured ferrite, SnFe 2 O 4 , by mechanochemical syntheses using HEBM of stoichiometric amounts of solid SnO and α-Fe 2 O 3 with acetone as surfactant was achieved progressively as function of ball milling time. Single phase SnFe 2 O 4 formation commenced from five hours of continuous ball milling, and reached completion after 22 hours, thereby yielding a material with a lattice parameter of 8.543 A, and particle size of 10.91 nm. The coercivity was 4.44 mT, magnetic saturation value of 17.75 Am 2 /kg, and remanent magnetizations of 1.50 Am 2 /kg, correspondingly. The nanosized particles exhibited superparamagnetic behavior phenomenon based on Moessbauer spectroscopy measurements. The kinetic analyses based on the modified Kissinger method yielded four characteristic stages during the thermal evolution of the 22 hours milled state with activation energies of 0.23 kJ/mol, 2.52 kJ/mol, 0.024 kJ/mol, and 1.57 kJ/mol respectively.

57Fe Moessbauer spectroscopic study of Japanese cedar bark - the variation in chemical states of iron due to influence of human activities

International Nuclear Information System (INIS)

Matsuo, Motoyuki; Kobayashi, Takaaki; Singh, T.B.; Tsurumi, Makoto; Ichikuni, Masami

1992-01-01

Chemical states of iron have been investigated by 57 Fe Moessbauer technique for the barks of Japanese cedar collected from urban and mountainous area of Japan. The Moessbauer spectra of all outer bark samples show two overlapping doublets and one sextet ascribable to paramagnetic ferrous, paramagnetic ferric and magnetic iron, respectively, whereas an inner bark sample consists only of the two doublets. The bark sample from urban area shows the higher relative amount of magnetic component and the smaller ferrous to ferric ratio. These features of iron species in the bark sample indicate that the bark sample can supply a more effective indicator of human activities than airborne particles collected directly by evaluation with an air sampler. (orig.)

Moessbauer Study of Electrodeposited Fe/Fe-Oxide Multilayers

International Nuclear Information System (INIS)

Kuzmann, E.; Homonnay, Z.; Klencsar, Z.; Vertes, A.; Lakatos-Varsanyi, M.; Miko, A.; Varga, L.K.; Kalman, E.; Nagy, F.

2005-01-01

Iron has been deposited electrochemically by short current pulses in Na-saccharin containing FeII-chloride and sulphate solution electrolytes. Combined electrochemical techniques with initial pulse plating of iron nanolayer and its subsequent anodic oxidation under potential control have been used for production of Fe/Fe-oxide multilayers. 57Fe CEM spectra of pulse plated iron revealed the presence of a minor doublet attributed mainly to γ-FeOOH in addition to the dominant sextet of α-iron. In the case of anodically oxidized pulse plated iron and of samples after repeated deposition of anodically oxidized pulse plated iron an additional minor doublet, assigned to ferrous chloride, also appears in the Moessbauer spectra. A significant change in the magnetic anisotropy of α-iron was observed with the anodic oxidation. The thickness of the layers were estimated from the CEM spectrum data by a modified computer program of the Liljequist method. The coercive field and the power loss versus frequency data showed that the pulse plated iron cores are good inductive elements up to several kHz frequencies

Magneto-structural coupling and harmonic lattice dynamics in CaFe2As2 probed by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Li Zhiwei; Ma Xiaoming; Pang Hua; Li Fashen

2011-01-01

In this paper we present a detailed Moessbauer spectroscopy study of the structural and magnetic properties of the undoped parent compound CaFe 2 As 2 single crystal. By fitting the temperature dependence of the hyperfine magnetic field we show that the magneto-structural phase transition is clearly first order in nature and we also deduce the compressibility of our sample to be 1.67 x 10 -2 GPa -1 . Within Landau's theory of phase transition, we further argue that the observed phase transition may stem from the strong magneto-structural coupling effect. The temperature dependence of the Lamb-Moessbauer factor shows that the paramagnetic phase and the antiferromagnetic phase exhibit similar lattice dynamics in high-frequency modes with very close Debye temperatures, Θ D ∼ 270 K.

Moessbauer study of Slovak meteorites

Energy Technology Data Exchange (ETDEWEB)

Lipka, J.; Sitek, J.; Dekan, J., E-mail: julius.dekan@stuba.sk; Degmova, J. [Slovak University of Technology, Institute of Nuclear and Physical Engineering, Faculty of Electrical Engineering and Information Technology (Slovakia); Porubcan, V. [Comenius University, Faculty of Mathematics and Physics (Slovakia)

2013-04-15

{sup 57}Fe Moessbauer spectroscopy was used as an analytical tool in the investigation of iron containing compounds of two meteorites (Rumanova and Kosice) out of total of six which had fallen on Slovak territory. In the magnetic fraction of the iron bearing compounds in the Rumanova meteorite, maghemite, troilite and Fe-Ni alloy were identified. In the non-magnetic fraction silicate phases were found, such as olivine and pyroxene. The paramagnetic component containing Fe{sup 3 + } ions corresponds probably to small superparamagnetic particles. The Kosice meteorite was found near the town of Kosice in February 2010. Its magnetic fraction consists of a Fe-Ni alloy with the Moessbauer parameters of the magnetic field corresponding to kamacite {alpha}-Fe(Ni, Co) and troilite. The non-magnetic part consists of Fe{sup 2 + } phases such as olivine and pyroxene and traces of a Fe{sup 3 + } phase. The main difference between these meteorites is their iron oxide content. These kinds of analyses can bring important knowledge about phases and compounds formed in extraterrestrial conditions, which have other features than their terrestrial analogues.

Behaviour of Ca2Fe2O5 with Nb substitution and sintering temperatures seen by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Duhalde, S.; Saragovi, C.; Moraes, I.J.; Terrile, M.C.; Francisco, R.H.P.

1991-01-01

Moessbauer spectroscopy of samples of Ca 2 Fe 2-x Nb x O 5+x with x values ranging from 0 to 0.8 and sintering temperatures of 1200degC and 1300degC shows the presence of two magnetic fields and a paramagnetic signal. The behaviour of the parameters as a function of x and of the sintering temperatures are discussed and compared with XRD results. (orig.)

Moessbauer spectroscopic characterization of macromolecule-metallochlorophyll complexes

International Nuclear Information System (INIS)

Inoue, H.; Fukuda, K.; Nonomura, Y.; Fluck, E.

1993-01-01

The bis-adducts of iron chlorophylls with poly(4-vinylpyridine-costyrene) (PVP) have been prepared and characterized by 57 Fe Moessbauer spectroscopy. The Moessbauer parameters of the PVP-adducts of iron chlorophylls are typical of low-spin iron(II) complexes. The central iron(III) ion is spontaneously reduced upon the axial coordination of PVP to iron(III) chlorophylls. The general tendency in the spontaneous reduction of the iron(III) chlorophylls has been interpreted in terms of the σ-donor and π-acceptor power of the axial macromolecular ligand. (orig.)

Study of iron exchanged zeolites by Moessbauer effect and electron spin resonance spectroscopy

International Nuclear Information System (INIS)

Aguirre Campuzano, C.E.

1993-01-01

Crystalline iron exchanged NaY zeolites, prepared from aqueous solutions and calcined at atmospheric conditions, have been studied and characterized by XRD, Moessbauer and EPR spectroscopies and TGA analysis. Three iron sites are clearly distinguished from Moessbauer and EPR measurements. Firstly, characteristic Moessbauer and EPR spectra may arise from framework sites, suggesting that Fe has substituted Al. It is also found that their spectroscopic signals are not intensity affected by thermal treatments. Secondly, a Moessbauer doublet which may arise from octahedral sites in the large cavity of the zeolite, shows however, that this doublet and its EPR signal are intensity temperature affected. An additional line broadening is observed on the low velocity line of this doublet, Thirdly, characteristic Moessbauer and EPR signals, which are also intensity temperature dependent have been associated to accluded material, where the Moessbauer doublet presents the line broadening effect before mentioned. Such line broadening effect may be due to perturbing signals from iron ions in tetrahedral sites. Finally, it has been observed that during calcination of the FeY zeolites, the three characteristic EPR signals for the three iron sites, do not increase at the expenses of the other. A result that may suggest a strong bonding between Fe-site of the Y zeolite, irrespective of the iron source. (Author)

Iron-57 and iridium-193 Moessbauer spectroscopic studies of supported iron-iridium catalysts

International Nuclear Information System (INIS)

Berry, F.J.; Jobson, S.

1988-01-01

57 Fe and 193 Ir Moessbauer spectroscopy shows that silica- and alumina-supported iron-iridium catalysts formed by calcination in air contain mixtures of small particle iron(III) oxide and iridium(IV) oxide. The iridium dioxide in both supported catalysts is reduced in hydrogen to metallic iridium. The α-Fe 2 O 3 in the silica supported materials is predominantly reduced in hydrogen to an iron-iridium alloy whilst in the alumina-supported catalyst the iron is stabilised by treatment in hydrogen as iron(II). Treatment of a hydrogen-reduced silica-supported iron catalyst in hydrogen and carbon monoxide is accompanied by the formation of iron carbides. Carbide formation is not observed when the iron-iridium catalysts are treated in similar atmospheres. The results from the bimetallic catalysts are discussed in terms of the hydrogenation of associatively adsorbed carbon monoxide and the selectivity of supported iron-iridium catalysts to methanol formation. (orig.)

Aspartic acid interaction with cobalt(II) in dilute aqueous solution: A {sup 57}Co emission Moessbauer spectroscopic study

Energy Technology Data Exchange (ETDEWEB)

Kamnev, Alexander A.; Tugarova, Anna V. [Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences (Russian Federation); Kovacs, Krisztina; Homonnay, Zoltan, E-mail: homonnay@ludens.elte.hu; Kuzmann, Erno; Vertes, Attila [Eoetvoes Lorand University, Institute of Chemistry (Hungary)

2012-03-15

Emission ({sup 57}Co) Moessbauer spectra of the aspartic acid-{sup 57}CoCl{sub 2} system were measured at T = 80 K in frozen aqueous solution and in the form of a dried residue of this solution. The Moessbauer spectra, besides a weak contribution from after-effects, showed two Fe{sup 2 + }/Co{sup 2 + } components which were ascribed to octahedrally and tetrahedrally coordinated {sup 57}Co{sup II} microenvironments in the Asp-cobalt(II) complex. This dual coordination mode may be due to the involvement of the second terminal carboxylic group of aspartic acid in the coordination sphere of Co.

Moessbauer Study of Discoloration of Synthetic Resin Covered Electric Switches

International Nuclear Information System (INIS)

Kuzmann, E.; Muzsay, I.; Homonnay, Z.; Vertes, A.

2002-01-01

57 Fe Moessbauer spectroscopy and X-ray diffractometry were used to investigate brown discoloration and sediments formed on the surface of synthetic resin product covered electronic switches. The Moessbauer measurement revealed that alloyed steels and iron-containing corrosion products are associated with the discolored layers. Iron, and iron corrosion products were shown by both MS and XRD in the sediments formed eventually during the finishing of the synthetic resin products after machining and washing with water solution.

Characterization of Maghsail meteorite from Oman by Moessbauer spectroscopy, X-ray diffraction and petrographic microscopy

International Nuclear Information System (INIS)

Al-Rawas, A. D.; Gismelseed, A. M.; Al-Kathiri, A. F.; Elzain, M. E.; Yousif, A. A.; Al-Kathiri, S. B.; Widatallah, H. M.; Abdalla, S. B.

2008-01-01

The meteorite found at Maghsail (16 55 70 N-53 46 69 E) west of Salalah Oman, has been studied by 57 Fe Moessbauer spectroscopy, X-diffractometry and petrographic microscopy. In the polished section the meteorite exhibits a porphyritic texture consisting of pyroxene and olivine phenocrysts in a fine to medium grained ground mass in addition to minor phases possibly skeletal chromite, troilite and minute amount of iron oxides. X-ray diffraction supports the existence of these compounds. The Moessbauer spectra of powdered material from the core of the rock at 298 K and 78 K exhibit a mixture of magnetic and paramagnetic components. The paramagnetic components are assigned to the silicate minerals olivine and pyroxene. On the other hand, the magnetic spectra reveal the presence of troilite and iron oxides. The petrographic analyses indicate that the iron oxides are terrestrial alteration products.

Moessbauer spectroscopy study of iron corrosion underneath painting system

International Nuclear Information System (INIS)

Nigam, R.K.; Hajela, B.P.; Sengupta, S.; Srivastava, B.C.; Gupta, K.N.

1986-01-01

The effect of pigments on the development of corrosion products between the painting system and metal surface when exposed to marine environments has been discussed. The pigments studied were: red mud zinc chromate, zinc chromate, red oxide zinc phosphate, manganese phosphate barium chromate and basic lead silico chromate. Moessbauer spectroscopy revealed that the upper rust layer in all the cases consisted of γ-Fe 2 O 3 , γ-FeOOH and α-FeOOH. The lower rust layer immediately in contact with the metal surface consisted of an asymmetrical doublet due to γ-FeOOH. (Auth.)

Paramagnetic hyperfine interactions of iron in solid ammonia from Moessbauer spectroscopy

International Nuclear Information System (INIS)

Litterst, F.J.; Saitovitch, E.M.B.; Terra, J.

1988-01-01

Moessbauer studies on highly dilute 57 Fe in solid ammonia are reported. The hyperfine parameters of the paramagnetic reaction product FeNH 3 point to a nearly atomic configuration of iron [Ar]3d 7 4s. The electronic spin relaxation slows down rapidly under application of an external magnetic field. The field dependence of the magnetic hyperfine patterns indicates a strong axial magnetic anisotropy. (author) [pt

Study of Phase Transformations on Nano-Crystalline (La,Sr)(Mn,Fe)O3 Systems by High-Pressure Moessbauer Spectroscopy

International Nuclear Information System (INIS)

Chandra, Usha; Mudgal, Prerana; Kumar, Manoj

2006-01-01

We report pressure-dependent 57Fe Moessbauer studies on a nano-crystalline perovskite La0.8Sr0.2(Mn0.8Fe0.2) O3 system up to 10 GPa using diamond anvil cell. At ambient pressure, iron is present as Fe3+ and Fe4+ in two different environments. Pressure seems to affect the higher symmetry site of Fe4+, while the octahedral site containing Fe3+ remains almost unaffected. Phase transformations are observed at pressures 0.52 GPa and 3.7 GPa respectively. A sudden increase in the isomer shift at 0.52 GPa is related to the reduction of Fe4+ ions while at 3.7 GPa, a structural transition is observed with sudden drop in isomer shift indicating Fe3+ ions in identical environment. Quadrupole splittings increase continuously with pressures up to 10 GPa

Moessbauer diffraction study of the Neel phase transition in Fe3BO6 crystal

International Nuclear Information System (INIS)

Kovalenko, P.P.; Labushkin, V.G.; Sarkisov, Eh.R.; Tolpekin, I.G.

1987-01-01

Phase transitions in a 57 Fe 3 BO 6 monocrystal in the vicinity of the Neel point, T N =507.5 K were investigated by means of the Moessbauergraphy. For the first time the relaxation type of Moessbauer spectra was observed near the phase transition point. First in the Moessbauer diffraction spectrum of the crystal the simultaneous presence of a component resulted from magnetic ordering and a paramagnetic component was observed

Moessbauer spectroscopy of the transformation of epsilon carbide during the tempering of Fe-C martensite - the existence of highly faulted cementite

International Nuclear Information System (INIS)

Genin, J.M.; Le Cear, G.; Simon, A.

1975-01-01

The results are reported of experimental verification of literature data on the transformation of epsilon carbide resulting from tempering Fe-C martensite at room temperature. Moessbauer spectroscopy was used in the experiments. The existence was ascertained of the considerable amount of faults previously found by electron diffraction. The possible cause of the faults are discussed. (L.O.)

High field Moessbauer study of dilute Ir-(Fe) alloys

International Nuclear Information System (INIS)

Takabatake, Toshiro; Mazaki, Hiromasa; Shinjo, Teruya.

1981-01-01

The magnetic behavior of very dilute Fe impurities in Ir has been studied by means of Moessbauer measurement in external fields up to 80 kOe at 4.2 K. The saturation hyperfine field increases in proportion to the external field up to the maximum magnetic field available. This means that for a localized spin fluctuation system IrFe, the effective magnetic moment associated with Fe impurities is induced in proportion to the external field. No anomalous spectrum was observed with a very dilute sample (--10 ppm 57 Co), indicating that the interaction between impurities is responsible for the anomalous spectrum previously observed with a less homogeneous sample. (author)

Moessbauer spectroscopic investigations of Fe/Mn-Fischer-Tropsch-catalysts

International Nuclear Information System (INIS)

Deppe, P.; Papp, H.; Rosenberg, M.

1986-01-01

The phase composition of Fe/Mn oxide catalysts of different compositions after 200 h of Fischer-Tropsch synthesis have been investigated by Moessbauer spectroscopy at room temperature, 77 K and 5 K. The final composition of the bulk catalysts depends strongly on the Mn content and the temperature of reduction before the synthesis. Catalytic activity and selectivity are partly correlated to this phase composition. (Auth.)

Moessbauer of phase separation in FeNi multilayers under ion bombardment

Energy Technology Data Exchange (ETDEWEB)

Amaral, L.; Paesano, A.; Brueckman, M.E. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Scorzelli, R.B.; Dominguez, A.B. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Shinjo, T.; Ono, T.; Hosoito, N. [Kyoto Univ. (Japan). Inst. for Chemical Research

1997-01-01

We investigated the effect of noble gas irradiation (He, Ne, Ar and Xe) on the Fe-Ni multilayers with a very thin modulation and nominal composition in the invar region Fe{sub 0.63} Ni{sub 0.37}. The evaluation of the formation/stability of the Fe-Ni phases formed under irradiation with different ions and doses was followed by conversion electron Moessbauer spectroscopy (CEMS). (author). 21 refs., 4 figs., 2 tabs.; e-mail: scorza at novell.cat.cbpf.br.

Thermal treatment of the Fe78Si9B13 alloy in it amorphous phase studied by means of Moessbauer spectroscopy

International Nuclear Information System (INIS)

Cabral P, A.; Lopez, A.; Garcia S, F.

2003-01-01

The magnetic and microhardness changes, dependents of the temperature that occur in the Fe 78 Si 9 B 13 alloy in it amorphous state were studied by means of the Moessbauer spectroscopy and Vickers microhardness. According to the Moessbauer parameters and in particular that of the hyperfine magnetic field, this it changes according to the changes of the microhardness; i.e. if the microhardness increases, the hyperfine magnetic field increases. The registered increment of hardness in the amorphous state of this alloy should be considered as anomalous, according to the prediction of the Hall-Petch equation, the one that relates negative slopes with grain sizes every time but small. (Author)

TEM and Moessbauer Study of Nano Sized Fe2MnAl Flakes

International Nuclear Information System (INIS)

Vinesh, A.; Sudheesh, V. D.; Lakshmi, N.; Venugopalan, K.

2011-01-01

Magnetic and structural properties of L21 ordered Fe 2 MnAl Heusler alloy have been studied by X-ray diffraction, Transmission electron microscopy (TEM), Moessbauer spectroscopy and DC magnetization. Structural texturing induced by ball milling is destroyed on heating while Moessbauer and DC magnetization studies show magnetic texturing persists after thermal treatment. TEM shows large distribution in particle size with an average size of 27 nm. Thermal annealing of ball milled sample results L2 1 ordering and the needle shaped particle contributes spin texturing.

Some antarctic lacustrine sediments from northern Victoria Land investigation by Moessbauer spectroscopy, INNA and XRD

International Nuclear Information System (INIS)

Stievano, L.; Bertelle, M.; Leotta, G.; Calogero, S.; Constantinescu, S.; Oddone, M.

1999-01-01

Fifteen lacustrine sediments, sampled during the 1994-1995 Austral summer in Northern Victoria Land (Antarctica), were characterised by 57 Fe Moessbauer spectroscopy, instrumental neutron activation analysis and X-ray diffraction. These sediments are related to the intrusive rocks from Granite Harbour, to the metamorphic rocks of the Complex of Wilson Terrane and the volcanic rocks from Mc Murdo. The samples contain quartz, alkaline feldspars, plagioclases, amphiboles, biotite, chlorite and muscovite except for the sediments of volcanic origin that contain alkaline feldspars, plagioclases and pyroxenes. The paramagnetic components of the Moessbauer spectra were assigned mainly to the iron sides in biotites except for those displayed from the sediments of volcanic origin assigned mainly to pyroxenes. Moessbauer spectra at room temperature do not display magnetic ordering except for those of the sediments of volcanic origin containing bulk magnetite, hematite and goethite. Moessbauer spectra collected at the liquid helium temperature always exhibit magnetic ordering. This spectral difference has been attributed to the different dimensions of the iron oxide particles in the sediments. The scarce weathering involves a partial transformation of magnetite in hematite and goethite in the sediment of volcanic origin. In the remaining sediments a partial hydrolysis of biotite together with a partial oxidation of iron (II) retained in silicates is present. (authors)

Microstructure, magnetic and Moessbauer studies on spark-plasma sintered Sm-Co-Fe/Fe(Co) nanocomposite magnets

Energy Technology Data Exchange (ETDEWEB)

Rao, N V Rama; Saravanan, P; Gopalan, R; Raja, M Manivel; Rao, D V Sreedhara; Chandrasekaran, V [Defence Metallurgical Research Laboratory, Hyderabad-500 058 (India); Sivaprahasam, D [International Advanced Research Centre for Powder Metallurgy and New Materials Hyderabad-500 005 (India); Ranganathan, R [Saha Institute of Nuclear Physics, Kolkata-700 064 (India)], E-mail: rg_gopy@yahoo.com

2008-03-21

Nanocomposite powders comprising Sm-Co-Fe intermetallic phases and Fe(Co) were synthesized by high-energy ball milling and were consolidated into bulk magnets by the spark-plasma sintering (SPS) technique. While the microstructure of the SPS samples was characterized by transmission electron microscopy (TEM), the solubility of Fe in different phases was investigated using Moessbauer spectroscopy. TEM studies revealed that the spark-plasma sintered sample has Sm(Co,Fe){sub 5} as a major phase with Sm{sub 2}(Co,Fe){sub 17}, Sm(Co,Fe){sub 2} and Fe(Co) as secondary phases. The size of the nanocrystalline grains of all these phases was found to be in the range 50-100 nm. The Moessbauer spectra of the as-milled powders exhibited two different subspectra: a sextet corresponding to the Fe phase and a broad sextet associated with the Fe(Co) phase; while that of the SPS sample showed four different subspectra: a sextet corresponding to Fe and other three sextets corresponding to the Fe(Co), Sm(Co,Fe){sub 5} and Sm{sub 2}(Co,Fe){sub 17} phases; these results are in accordance with the TEM observation. Recoil magnetization and reversible susceptibility measurements revealed magnetically single phase behaviour of the SPS magnets.

Influence of Heat Treatment on Ordering Process in Fe72Al28 Alloy Studied by Moessbauer Spectroscopy

International Nuclear Information System (INIS)

Kansy, J.; Hanc, A.; Giebel, D.

2011-01-01

The paper discusses a theoretical model that associates the shape of Moessbauer spectrum with the configuration of atoms in local surroundings of the Moessbauer nuclide. The model has been implemented to a computer program which was used to analyse the Moessbauer spectra of Fe 72 Al 28 alloys after various heat treatments. Basing on the determined configuration of atoms, the long range ordering parameter was estimated. (authors)

High field Moessbauer and magnetic investigations of Pr0.73Fe4Sb12

International Nuclear Information System (INIS)

Reissner, Michael; Bauer, Ernst; Steiner, Walter; Rogl, Peter

2004-01-01

In accordance with the filling factor determined by X-ray investigations two Fe sites were identified in the in-field 57 Fe Moessbauer spectra. The derived internal fields at 4.2 K were small (0.35 and 1.45 T at external fields of 13.5 T), whereas from magnetic measurements μ eff ∼2.7 μ B was estimated for the Fe 4 Sb 12 -sublattice

Moessbauer spectroscopy evidence of intrinsic non-stoichiometry in iron telluride single crystals

Energy Technology Data Exchange (ETDEWEB)

Kiiamov, Airat G.; Tayurskii, Dmitrii A. [Institute of Physics, Kazan Federal University (Russian Federation); Centre for Quantum Technologies, Kazan Federal University (Russian Federation); Lysogorskiy, Yury V.; Vagizov, Farit G. [Institute of Physics, Kazan Federal University (Russian Federation); Tagirov, Lenar R. [Institute of Physics, Kazan Federal University (Russian Federation); E.K. Zavoisky Physical-Technical Institute, Russian Academy of Sciences, Kazan (Russian Federation); Croitori, Dorina [Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau (Moldova, Republic of); Tsurkan, Vladimir [Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau (Moldova, Republic of); Experimental Physics V, University of Augsburg (Germany); Loidl, Alois [Experimental Physics V, University of Augsburg (Germany)

2017-04-15

The FeTe parent compound for iron-superconductor chalcogenides was studied applying Moessbauer spectroscopy accompanied by ab initio calculations of electric field gradients at the iron nuclei. Room-temperature (RT) Moessbauer spectra of single crystals have shown asymmetric doublet structure commonly ascribed to contributions of over-stoichiometric iron or impurity phases. Low-temperature Moessbauer spectra of the magnetically ordered compound could be well described by four hyperfine-split sextets, although no other foreign phases different from Fe{sub 1.05}Te were detected by XRD and microanalysis within the sensitivity limits of the equipment. Density functional ab initio calculations have shown that over-stoichiometric iron atoms significantly affect electron charge and spin density up to the second coordination sphere of the iron sub-lattice, and, as a result, four non-equivalent groups of iron atoms are formed by their local environment. The resulting four-group model consistently describes the angular dependence of the single crystals Moessbauer spectra as well as intensity asymmetry of the doublet absorption lines in powdered samples at RT. We suppose that our approach could be extended to the entire class of Fe{sub 1+y}Se{sub 1-x}Te{sub x} compounds, which contain excess iron atoms. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Seasonal variation of iron speciation in a pearl-raising bay sediment by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Kuno, Akihito; Matsuo, Motoyuki; Chiba, Satoshi; Yamagata, Yoichi

2008-01-01

Ago Bay in Mie Prefecture, central Japan, is world-famous for the site of Mikimoto pearl culture, but recently the production of pearls has considerably declined. Environmental deterioration of the bay is suspected of having caused the decline. The periodic investigation into iron speciation of the bay sediment by 57 Fe Moessbauer spectroscopy revealed its high pyrite (FeS 2 ) content from the surface to the 20-cm depth. The pyrite in the surface sediment decreased only in spring, three months after the dissolved oxygen in the bottom water was at maximum. Such oxygen-consuming material as pyrite accumulated through long-term biotic activity is a most-likely explanation for the prolonged environmental deterioration of the bay, which appears in the high chemical oxygen demand (COD) of the sediment. (author)

Moessbauer studies of superexchange interactions in NiFe sub 2 O sub 4

CERN Document Server

Kim, S J; Kim, C S; Lee, S W

2000-01-01

NiFe sub 2 O sub 4 has been studied using Moessbauer spectroscopy and X-ray diffraction. The crystal was found to have a inverse cubic spinel structure with the lattice constant a sub 0 =8.326+-0.003 A. Moessbauer spectra of NiFe sub 2 O sub 4 was obtained at various absorber temperatures from 13 K to the Neel temperature. The Moessbauer spectra consisted of two sets of six lines corresponding to Fe sup + sup 3 at the tetrahedral (A) and the octahedral (B) sites. The temperature dependence of the magnetic hyperfine fields at sup 5 sup 7 Fe nuclei at the tetrahedral (A) and the octahedral (B) sites was analyzed by the Neel theory of ferrimagnetism. The intersublattice A-O-B and intrasublattice A-O-A superexchange interactions were found to be antiferromagnetic with strengths of J sub A sub - sub B =-25.0 k sub B and J sub A sub - sub A =-4.0 K sub B , respectively, while the intrasublattice B-O-B superexchange interaction is ferromagnetic with a strength J sub B sub - sub B =4.2 k sub B.

Oxygen vacancy and Moessbauer parameters of Fe doped tin oxides

International Nuclear Information System (INIS)

Nomura, K.; Mudarra Navarro, A.M.; Errico, L.; Rodriguez Torres, C.E.

2013-01-01

It is not clear what the local environment of Fe ions included in rutile structure is. In order to clarify this point, Moessbauer parameters of 57 Fe doped SnO 2 are compared with the results of ab initio calculation taking into account different configurations of iron and oxygen vacancy in the rutile structure of SnO 2 . Calculations were performed using the LAPW+lo method (Wien2k); RMT x Kmax = 7, A mesh of 50 k-points at IBZ, 2x2x2 super cell of SnO 2 . (J.P.N.)

Moessbauer characterization of calcium-ferrite oxides prepared by calcining Fe2O3 and CaO

International Nuclear Information System (INIS)

Hirabayashi, Daisuke; Sakai, Yoichi; Yoshikawa, Takeshi; Mochizuki, Kazuhiro; Kojima, Yoshihiro; Suzuki, Kenzi; Ohshita, Kazumasa; Watanabe, Yasuo

2006-01-01

Calcium ferrite oxides were prepared by calcining a mixture powder of iron- and calcium oxide. The 57 Fe-Moessbauer spectra of the calcium ferrites oxides were measured, revealing that the products should be Ca 2 Fe 2 O 5 and CaFe 2 O 4 , the ratio of which was dependent of the Fe/Ca atomic ratio of the mixture powder.

Moessbauer spectroscopy system with increased performance and flexibility - utilization in material research

International Nuclear Information System (INIS)

Pechousek, J.; Novak, P.; Navarik, J.; Machala, L.

2013-01-01

Transmission Moessbauer Spectroscopy (TMS) is used for structural, phase, and magnetic characterization of mostly iron containing samples (commonly Fe, Sn, Ni, Zn, Eu etc.). Moessbauer Spectroscopy (MS) is a highly element selective method and in details it provides determination and quantification of phase composition of samples including amorphous and nanocrystalline; determination of valence and spin states of iron atoms, differentiation of structure positions of iron atoms, stoichiometry examination of cation substitution; magnetic state determination and local configuration of magnetic moments of the atoms; measurement of temperature dependences, measurement in external magnetic field; determination of magnetic properties including temperatures of magnetic transitions; and study of mechanism and kinetics of reactions in solid phase, phase transformations. (authors)

Moessbauer spectroscopy of metals from birth to death

International Nuclear Information System (INIS)

Fujita, Francisco Eiichi

1998-01-01

In today's metallurgy, precision techniques, such as X-ray and electron diffraction, electron microscopy, infrared spectroscopy and electron probe micro-analyzer, are being indispensably used, and, comparing to them, Moessbauer spectroscopy is not inferior at all in usefulness, convenience and cost benefit. Actually, however, it is not yet popular among the metallurgists probably because people believe that the Moessbauer effect is a difficult physics, radioactive sources are difficult to handle, and spectral analyses are complicated. These beliefs are in fact groundless and must be dissolved for further diffusion of this useful Moessbauer technique in metals and other industries.The present introductory talk intends to help people's better understanding and no anxiety for using the Moessbauer spectroscopy by showing how it can be applied to various problems of metals and alloys from their birth to the end, that is, from the study of minerals and ores before smelting to that of corrosion and other failures.Firstly, the principle of Moessbauer spectroscopy will be explained with simplest illustrations together with simple pictures of apparatuses including the high temperature furnace and the high pressure cell.In the second will be shown typical examples of Moessbauer patterns of magnetite, carbon steel and other alloys, with indications of how to analyze the seemingly complicated spectra. Some other examples will be shown with special apparatuses easy to measure. The usefulness and convenience of Moessbauer spectroscopy will be understood again from these examples. More examples will be on amorphous alloys and other advanced materials

Moessbauer study of the magnetic filler for suppositories

International Nuclear Information System (INIS)

Bykov, A.V.; Nikolaev, V.I.; Shulgin, V.I.; Diaz, C.; Kharitonov, Yu.Ya.; Cherkasova, O.G.

1991-01-01

Moessbauer spectroscopy methods are discussed when applied to test the properties of magnetic suppositories used in medicine. The experiments were carried out on magnetic rectal suppositories containing paramadine and fine-dispersed ferrite powder (BaO.nFe 2 O 3 ) as a magnetic filler. According to the data on the value of effective magnetic field on 57 Fe nuclei in ferrite magnetic sublattices, the stoichiometric n-number equals approximately 5.5; this value corresponds to the composition range of optimal magnetic properties. (orig.)

Moessbauer Spectroscopy at the University of Dar Es Salaam

International Nuclear Information System (INIS)

Kiwanga, C.A.

1989-01-01

A recently acquired facility for Moessbauer spectroscopy is described. Test results on samples of an iron ore and a steel corrosion product are given. It is deduced that the iron ore contained hematite (alpha-Fe203) constituting 41.5%, magnetite (Fe 304) constituting of 39.5% and two doublet phases: a paramagnetic Fe 3+ phase constituting 4.8% and a paramagnetic Fe 2+ phase constituting 14.2%. The steel corrosion product seems to be entirely composed of lepidocrocite (gamma-FeOOH). The results obtained are in excellent agreement with the literature data with regard to the identified iron compounds. It is concluded that the facility including the data processing computer programs which are essentially home-made is capable of producing very high quality research findings. (author)

Moessbauer spectroscopy of metals from birth to death

Energy Technology Data Exchange (ETDEWEB)

Fujita, Francisco Eiichi [Osaka University (Japan)

1998-12-15

In today's metallurgy, precision techniques, such as X-ray and electron diffraction, electron microscopy, infrared spectroscopy and electron probe micro-analyzer, are being indispensably used, and, comparing to them, Moessbauer spectroscopy is not inferior at all in usefulness, convenience and cost benefit. Actually, however, it is not yet popular among the metallurgists probably because people believe that the Moessbauer effect is a difficult physics, radioactive sources are difficult to handle, and spectral analyses are complicated. These beliefs are in fact groundless and must be dissolved for further diffusion of this useful Moessbauer technique in metals and other industries.The present introductory talk intends to help people's better understanding and no anxiety for using the Moessbauer spectroscopy by showing how it can be applied to various problems of metals and alloys from their birth to the end, that is, from the study of minerals and ores before smelting to that of corrosion and other failures.Firstly, the principle of Moessbauer spectroscopy will be explained with simplest illustrations together with simple pictures of apparatuses including the high temperature furnace and the high pressure cell.In the second will be shown typical examples of Moessbauer patterns of magnetite, carbon steel and other alloys, with indications of how to analyze the seemingly complicated spectra. Some other examples will be shown with special apparatuses easy to measure. The usefulness and convenience of Moessbauer spectroscopy will be understood again from these examples. More examples will be on amorphous alloys and other advanced materials.

Moessbauer spectroscopy: Methodology and some applications to magnetic materials

International Nuclear Information System (INIS)

Sundqvist, T.

1986-01-01

The development of a new computer program for analysis of Moessbauer spectra that allows the user to make a detailed simulation of a measured spectrum is described. The program includes several novel computational algorithms as well as extensive treatment of experimental side effects. Data collection instrumentation has been improved by the development of computer based data acquisition units. Replacing traditional multichannel analyzers, these computer controlled units provide increased flexibility, improved capacity and ease of data handling. The systems designed range from a simple Apple II interface, to a high performance self contained computer controlled unit. The computerized spectrometers feature two independent channels, allowing for acquisition of the spectrum of interest and of a simultaneous calibration spectra, as well as software controlled frequency of operation. Moessbauer spectroscopy is applied to amorphous Fe based alloys to study the correlations among hyperfine interactions, and to study the crystallization behaviour of these alloys. Special attention has been payed to the quadrupole interaction in the amorphous phases. Careful data analysis, making use of the above mentioned program, is used in an attempt to determine the complex magnetic structures found in various iron phosphides. The usefulness of the Ni-61 isotope for Moessbauer spectroscopy has been investigated. (author)

Moessbauer spectroscopic characterization of ferrite ceramics

International Nuclear Information System (INIS)

Music, S.; Ristic, M.

1999-01-01

The principle of Moessbauer effect and the nature of hyperfine interactions were presented. The discovery of the Moessbauer effect was the basis of a new spectroscopic technique, called Moessbauer spectroscopy, which has already made important contribution to research in physics, chemistry, metallurgy, mineralogy and biochemistry. In the present work the selected ferrites such as spinel ferrite, NiFe 2 O 4 , and some rare earth orthoferrites and garnets were investigated using Moessbauer spectroscopy. X-ray powder diffraction and Fourier transform infrared spectroscopy were used as complementary techniques. The formation of NiFe 2 O 4 was monitored during the thermal decomposition of mixed salt (Ni(NO 3 ) 2 +2Fe(NO 3 ) 3 )nH 2 O. The ferritization of Ni 2+ ions was observed at 500 deg. C and after heating at 1300 deg. C the stoichiometric NiFe 2 O 4 was produced. The Moessbauer parameters obtained for NiFe 2 O 4 , d Fe = 0.36 mm s -1 and HMF = 528 kOe, can be ascribed to Fe 3+ ions in the octahedral sublattice, while parameters d Fe = 0.28 mm s -1 and HMF = 494 kOe can be ascribed to Fe 3+ ions in the tetrahedral lattice. The effect of ball-milling of NiFe 2 O 4 was monitored. The formation of oxide phases and their properties in the systems Nd 2 O 3 -Fe 2 O 3 , Sm 2 O 3 -Fe 2 O 3 , Gd 2 O 3 -Fe 2 O 3 , Eu 2 O 3 -Fe 2 O 3 and Er 2 O 3 -Fe 2 O 3 were also investigated. Quantitative distributions of oxide phases, a-Fe 2 O 3 , R 2 O 3 , R 3 Fe 5 O 12 and RFeO 3 , R = Gd or Eu, were determined for the systems xGd 2 O 3 +(1-x)Fe 2 O 3 and xEu 2 O 3 +(1-x)Fe 2 O 3 . The samples, prepared by chemical coprecipitation in the system xEu 2 O 3 +(1-x)Fe 2 O 3 , 0≤x≤1, were completely amorphous as observed by XRD, even at the relatively high temperature of the sample preparation (600 deg. C). Similar behavior was observed during the formation of Er 3 Fe 5 O 12 . Moessbauer spectroscopy indicated that this 'amorphous' phase is actually composed of very small and/or poor

Studies on corrosion of mild steel by water using Moessbauer spectroscopy

International Nuclear Information System (INIS)

Nigam, A.N.; Tripathi, R.P.; Jangid, M.L.

1987-01-01

The corrosion of mild steel as a result of interaction with various types of local natural water samples and distilled water is studied with the help of Moessbauer spectroscopy. The data are supplemented with the studies on IR and magnetic properties as and when required. Distilled water and potable water behave in almost similar fashion wherein ferrihydrite and FeOOH are observed to be the precursors of magnetite, the end corrosion product. In case of brakish water, the additional species, viz., FeCl 2 , βFeOOH and an intermediate possibly FeOCl are accounted, and possible mechanisms are suggested. (author)

Freeze-quench (57)Fe-Mössbauer spectroscopy: trapping reactive intermediates.

Science.gov (United States)

Krebs, Carsten; Bollinger, J Martin

2009-01-01

(57)Fe-Mössbauer spectroscopy is a method that probes transitions between the nuclear ground state (I=1/2) and the first nuclear excited state (I=3/2). This technique provides detailed information about the chemical environment and electronic structure of iron. Therefore, it has played an important role in studies of the numerous iron-containing proteins and enzymes. In conjunction with the freeze-quench method, (57)Fe-Mössbauer spectroscopy allows for monitoring changes of the iron site(s) during a biochemical reaction. This approach is particularly powerful for detection and characterization of reactive intermediates. Comparison of experimentally determined Mössbauer parameters to those predicted by density functional theory for hypothetical model structures can then provide detailed insight into the structures of reactive intermediates. We have recently used this methodology to study the reactions of various mononuclear non-heme-iron enzymes by trapping and characterizing several Fe(IV)-oxo reaction intermediates. In this article, we summarize these findings and demonstrate the potential of the method. © Springer Science+Business Media B.V. 2009

Moessbauer study of the magnetic filler for suppositories

Energy Technology Data Exchange (ETDEWEB)

Bykov, A.V.; Nikolaev, V.I.; Shulgin, V.I. (M.V. Lomonosov Moscow State Univ. (USSR)); Diaz, C. (Cuba National Center of Scientific Research, Havana (Cuba)); Kharitonov, Yu.Ya.; Cherkasova, O.G. (I.M. Sechenov First Moscow Medical Inst. (USSR))

1991-11-01

Moessbauer spectroscopy methods are discussed when applied to test the properties of magnetic suppositories used in medicine. The experiments were carried out on magnetic rectal suppositories containing paramadine and fine-dispersed ferrite powder (BaO.nFe[sub 2]O[sub 3]) as a magnetic filler. According to the data on the value of effective magnetic field on [sup 57]Fe nuclei in ferrite magnetic sublattices, the stoichiometric n-number equals approximately 5.5; this value corresponds to the composition range of optimal magnetic properties. (orig.).

Electronic phase diagrams and competing ground states of complex iron pnictides and chalcogenides. A Moessbauer spectroscopy and muon spin rotation/relaxation study

Energy Technology Data Exchange (ETDEWEB)

Kamusella, Sirko

2017-03-01

In this thesis the superconducting and magnetic phases of LiOH(Fe,Co)(Se,S), CuFeAs/CuFeSb, and LaFeP{sub 1-x}As{sub x}O - belonging to the 11, 111 and 1111 structural classes of iron-based arsenides and chalcogenides - are investigated by means of {sup 57}Fe Moessbauer spectroscopy and muon spin rotation/relaxation (μSR). Of major importance in this study is the application of high magnetic fields in Moessbauer spectroscopy to distinguish and characterize ferro- (FM) and antiferromagnetic (AFM) order. A user-friendly Moessbauer data analysis program was developed to provide suitable model functions not only for high field spectra, but relaxation spectra or parameter distributions in general. In LaFeP{sub 1-x}As{sub x}O the reconstruction of the Fermi surface is described by the vanishing of the Γ hole pocket with decreasing x. The continuous change of the orbital character and the covalency of the d-electrons is shown by Moessbauer spectroscopy. A novel antiferromagnetic phase with small magnetic moments of ∼ 0.1 μ{sub B} state is characterized. The superconducting order parameter is proven to continuously change from a nodal to a fully gapped s-wave like Fermi surface in the superconducting regime as a function of x, partially investigated on (O,F) substituted samples. LiOHFeSe is one of the novel intercalated FeSe compounds, showing strongly increased T{sub C} = 43 K mainly due to increased interlayer spacing and resulting two-dimensionality of the Fermi surface. The primary interest of the samples of this thesis is the simultaneously observed ferromagnetism and superconductivity. The local probe techniques prove that superconducting sample volume gets replaced by ferromagnetic volume. Ferromagnetism arises from magnetic order with T{sub C} = 10 K of secondary iron in the interlayer. The tendency of this system to show (Li,Fe) disorder is preserved upon (Se,S) substitution. However, superconductivity gets suppressed. The results of Moessbauer spectroscopy

The Moessbauer spectroscopy in the characterization of atmospheric corrosion products

International Nuclear Information System (INIS)

Hernandez Torres, D.; Leiva Ronda, P.; Gomez, J.; Ronda, M.

1996-01-01

A study of corrosion products on mild steel formed after 1 and 5 years exposure in two industrial coastal weathering stations in the Bay from Matanzas City, Cuba, has been carried out. Structural analysis was conducted using mainly transmission Moessbauer Spectroscopy and the X-ray diffraction as complementary technique. The main phases found in the specimen exposed to high chloride containing environment were: lepidocrocite (γ- FeOOH), goethite (α- FeOOH) and magnetite concentration was the lowest, the phases found were γ- FeOOH and α- FeOOH, and the phase transformation proposed was γ- FeOOh -> α- Fe-OOH. In this station were found also amorphous corrosion products. There amorphous phases could be responsible for the lowest levels of corrosion on steel in this station

Characterization of catalysts by Moessbauer spectroscopy: An application to the study of Fischer-Tropsch, hydrotreating and super Claus catalysts

International Nuclear Information System (INIS)

Kraan, A.M. van der; Boellaard, E.; Craje, M.W.J.

1993-01-01

Moessbauer spectroscopy is an excellent in-situ technique for the identification of phases present in catalysts. Applied to metallic iron catalysts used in the Fischer-Tropsch reaction it reveals a detailed picture of the carburization process and provides insight into the relation between the properties of the catalytic material and its activity. The influence of a support and the effect of alloying iron with an (in)active metal on the catalytic performance is discussed for Fe, Cu-Fe and Ni-Fe systems. In addition, Moessbauer spectroscopy is used for the identification of 'Co-sulfide' species present in sulfided Co and CoMo catalysts applied in one of the largest chemical processes in the world, the hydrotreatment of crude oil. A structural model is proposed. Finally, the contribution of Moessbauer spectroscopic studies to the development of a new catalyst for cleaning of Claus tail gas via selective oxidation of hydrogen sulfide to elemental sulfur is discussed. (orig.)

Moessbauer Study of Iron-Containing Carbon Nanotubes

Energy Technology Data Exchange (ETDEWEB)

Marco, J. F.; Gancedo, J. R. [CSIC, Instituto de Quimica-Fisica ' Rocasolano' (Spain); Hernando, A.; Crespo, P.; Prados, C.; Gonzalez, J. M. [Instituto de Magnetismo Aplicado (Spain); Grobert, N.; Terrones, M.; Walton, D. R. M.; Kroto, H. W. [University of Sussex, Fullerene Science Centre, School of Chemistry, Physics and Environmental Science (United Kingdom)

2002-03-15

{sup 57}Fe transmission Moessbauer at temperatures between 18 and 298 K and magnetic measurements have been used to characterize Fe-filled carbon nanotubes which were prepared by pyrolisis of Ferrocene + C{sub 60} at atmospheric pressure under an Ar atmosphere at 1050{sup o}C. The Moessbauer data have shown that the Fe phases encapsulated within the carbon nanotubes are {alpha}-Fe, Fe{sub 3}C and {gamma}-Fe. The magnetic results are compatible with the Moessbauer data. Taken together the results allow us to propose a simple picture of the distribution of iron phases within the carbon nanotubes which would consist of an {alpha}-Fe core surrounded by an {gamma}-Fe shell, finally covered by an Fe{sub 3}C layer.

Theoretical study of Moessbauer hyperfine parameters of Fe bound to ammonia

International Nuclear Information System (INIS)

Terra, J.; Guenzburger, D.

1995-01-01

The first-principles Discrete Variational method was employed to study the species formed by the interaction of an Fe atom and ammonia. Total energy calculations were performed for several configurations. The hyperfine parameters isomer shift, quadrupole splitting and magnetic hyperfine were calculated for the ground state found, and compared to reported experimental values obtained by Moessbauer spectroscopy in frozen ammonia. (author). 14 refs, 1 tab

Efficiency analysis of clearance of two types of exogenous iron from the rat brain by Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Polikarpov, D. M., E-mail: polikarpov.imp@gmail.com; Cherepanov, V. M.; Gabbasov, R. R. [National Research Centre, ' Kurchatov Institute' (Russian Federation); Chuev, M. A.; Mischenko, I. N. [Russian Academy of Sciences, Russian Institute of Physics and Technology (Russian Federation); Korshunov, V. A. [Russian Academy of Sciences, Institute of Higher Nervous Activity and Neurophysiology (Russian Federation); Panchenko, V. Y. [National Research Centre, ' Kurchatov Institute' (Russian Federation)

2013-04-15

Fe{sub 3}O{sub 4} based ferrofluid was injected transcranially in the ventricle of the rat brain. At 3 months after the injection the rat was sacrificed and the brain was investigated by Moessbauer spectroscopy and histological Perls Prussian blue method. Joint analysis of histological and Moessbauer data confirms that superparamagnetic nanoparticles Fe{sub 3}O{sub 4}, which constituted about 91 % of the iron of the ferrofluid, were cleared from the brain, while the concomitant chemical compound containing ferric ion in the high-spin state, remains intact.

Local atomic order in nanocrystalline Fe-based alloys obtained by mechanical alloying

International Nuclear Information System (INIS)

Jartych, E.

2003-01-01

Using the 57 Fe Moessbauer spectroscopy, a local atomic order in nanocrystalline alloys of iron with Al, Ni, W and Mo has been determined. Alloys were prepared by mechanical alloying method. Analysis of Moessbauer spectra was performed on the basis of the local environment model in terms of Warren-Cowley parameters. It was shown that impurity atoms are not randomly distributed in the volume of the first and the second co-ordination spheres of 57 Fe nuclei and they form clusters

Moessbauer investigation of iron uptake in wheat

Energy Technology Data Exchange (ETDEWEB)

Kovacs, K., E-mail: kkriszti@bolyai.elte.hu [Eoetvoes Lorand University, Laboratory of Nuclear Chemistry, Institute of Chemistry (Hungary); Kuzmann, E. [Hungarian Academy of Sciences, Laboratory of Nuclear Chemistry, Chemical Research Center (Hungary); Fodor, F.; Cseh, E. [Eoetvoes Lorand University, Department of Plant Physiology (Hungary); Homonnay, Z.; Vertes, A. [Eoetvoes Lorand University, Laboratory of Nuclear Chemistry, Institute of Chemistry (Hungary)

2008-07-15

Iron uptake and distribution in wheat roots were studied with {sup 57}Fe Moessbauer spectroscopy. Plants were grown both in iron sufficient and in iron deficient nutrient solutions. Moessbauer spectra of the frozen iron sufficient roots exhibited three iron(III) components with the typical average Moessbauer parameters of {delta} = 0.50 mm s{sup -1}, {Delta} = 0.43 mm s{sup -1}, {delta} = 0.50 mm s{sup -1}, {Delta} = 0.75 mm s{sup -1} and {delta} = 0.50 mm s{sup -1}, {Delta} = 1.20 mm s{sup -1} at 80 K. These doublets are very similar to those obtained earlier for cucumber [0], which allows us to suppose that iron is stored in a very similar way in different plants. No ferrous iron could be identified in any case, not even in the iron deficient roots, which confirms the mechanism proposed for iron uptake in the graminaceous plants.

Moessbauer spectroscopic studies of the magnetic and structural properties of novel nanophase magnetic materials

International Nuclear Information System (INIS)

Milford, G.H.

2000-08-01

57 Fe Moessbauer Spectroscopy and complementary techniques have been used to characterise the physical and magnetic properties of a variety of novel nanophase iron containing magnetic particles, over a range of temperatures, and applied magnetic fields. Two series of commercially produced advanced metal particle pigments and tapes intended for use as magnetic recording media have been characterised using Transmission and Conversion Electron Moessbauer Spectroscopy at 4.2K, 77K and 293K. Moessbauer Spectra at 4.2K and 293K have identified two different forms of iron within the samples, an iron alloy core and an Fe 3+ oxide passivation layer. The first series of metal particle pigments studied is split into two separate groups, the core of the first group consists of a disordered Fe/Co alloy. Whereas the second group of metal particle pigments studied within the series have shown different characteristics than the previous samples, as the core is no longer a simple Fe/Co alloy. In addition to this the particle size is significantly reduced in the final sample within the series. This may be due to the presence of an Fe 2+ component, which appears to reduce the amount of Fe 3+ component necessary to passivate the particles by approximately half. The second series of samples have been used in part to investigate the out of plane angle of the metal particle pigments and its relationship with the squareness of the metal particle tapes. It is vital to minimise the out of plane angle of the metal particle tapes to obtain the optimum magnetic properties of the metal particle pigment. It has been shown that a decreasing out of plane angle leads to an increase in the squareness of the tapes. As a consequence of this the switching field distribution can be narrowed on metal particle tapes by reducing the out of plane angle. A further investigation has been carried out on the metal particle pigments coated onto tapes using Conversion Electron Moessbauer Spectroscopy, in order to

Observation of changing of the internal conversion coefficient under Moessbauer effect at magnetic transition in Rh-Fe system

International Nuclear Information System (INIS)

Ruskov, T.

1998-01-01

The magnetic disorder-order transition in the Rh-Fe alloy is studied by conversion electron Moessbauer spectroscopy. The drastic increase of the area under the Moessbauer spectrum at the transition from the paramagnetic to the magnetic state could be explained by diminishing the internal conversion coefficient. Thus our experimental results directly confirm the theory of the collective effect in the system of radiating developed by Yukalov

Moessbauer study of FePO4 cathode for lithium- and sodium-ion batteries

International Nuclear Information System (INIS)

Tetsuaki Nishida; Masahiro Tokunaga; Toshiharu Nishizumi; Takafumi Yamamoto; Tomoyuki Shiratsuchi; Shigeto Okada; Jun-ichi Yamaki

2005-01-01

LiFePO 4 of olivine type has attracted much interest as a rare-metal free cathode for lithium-ion battery. The present authors' group has found a low-cost preparation method for new cathode material FePO 4 (P 321 ) from an aqueous solution of metallic iron and P 2 O 5 . A cathode pellet was prepared by mixing FePO 4 , acetylene black (AB) and polytetrafluoroethylene (PTFE) binder at a mass ratio of 70:25:5. Electrochemical cathode performance was investigated under a constant current density of 0.1 mA/cm 2 with a coin-type cell with an anode of metallic Li and Na for Li- and Na-ion batteries, respectively. Moessbauer spectra were measured by a constant accele- ration method with a Moessbauer source of 57 Co(Pd) and an α-Fe foil as a reference of the isomer shift. Moessbauer spectra of the original cathode pellet top left and right) composed of amorphous FePO 4 indicate that all the Fe III atoms have a tetrahedral symmetry. After discharging the Li-(second left) and Na-batteries (second right), all the Fe III were reduced to octahedral Fe II . The reduction of Fe III to Fe II indicates penetration of Li + and Na + into the FePO 4 cathode which accompanies an electron capture; Li + (or Na + ) + Fe III PO 4 + e - = LiFe II PO 4 (or NaFe II PO 4 ) After charging the Li-cell (bottom left), all the Fen atoms were oxidized to tetrahedral Fe III , while 69 % of Fe II was oxidized to Fe III in the Na-ion cell (bottom right) due to a lower cell voltage: 4.0 V. Oxidation of Fe II to Fe III reflects a release of Li + or Na + ions from the FePO 4 cathode to the electrolyte, i.e., an inverse reaction of eq.

Moessbauer spectroscopy with synchrotron radiation

International Nuclear Information System (INIS)

Bergmann, U.

1994-01-01

The short pulse nature of synchrotron radiation makes it possible to perform Moessbauer spectroscopy in the time domain, i.e. instead of measuring the transmitted intensity time integrated as a function of source/absorber velocity, the intensity of the scattered radiation is measured time differential. The resulting time spectrum is essentially source independent and complications in the data analysis which are related to the radioactive source are completely removed. Furthermore, the large brightness and well defined polarization of the synchrotron radiation can, e.g., speed up the data collection and facilitate studies of polarization phenomena. To illustrate these new spectroscopic possibilities, measurements of the temperature dependence and polarization dependence of forward scattering from alpha - sup 5 sup 7 Fe nuclei are presented and discussed 26 refs., 5 figs. (author)

Moessbauer spectroscopy in space

Energy Technology Data Exchange (ETDEWEB)

Klingelhoefer, G [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Held, P [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Teucher, R [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Schlichting, F [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Foh, J [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Kankeleit, E [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik

1995-03-01

Nearly 40 years after the discovery of the Moessbauer effect for the first time a Moessbauer spectrometer will leave our planet to explore in situ the surface of another solar system body: the red planet Mars [1]. We are currently developing a miniaturized Moessbauer spectrometer (MIMOS) which is part of the scientific payload of the Russian Mars96 mission, to be launched within the next 2-4 years [2,3]. To fulfill the requirements for a space mission to the planet Mars, all parts of the spectrometer had to be extremely miniaturized and ruggedized to withstand the space flight and Mars environmental conditions. The relevant parts (e.g. drive, detector system, electronics etc.) will be described in more detail and its characteristics compared to standard systems. Because of this new development there now is a growing interest to include a Moessbauer (MB) instrument in future space missions to other solar system bodies as for instance Venus, the terrestrial Moon, and a comet nucleus. Because of extremely different environmental conditions (e.g. nearly zero gravity on the surface of a comet nucleus, high pressure and temperature on the surface of Venus, etc.) different instrument designs and concepts are required for different missions. We will present some ideas for various types of missions, as well as the motivation for using Moessbauer spectroscopy in these cases. (orig.)

Analysis of iron state in some Argentinian soils by dissolution methods and Moessbauer spectroscopy

International Nuclear Information System (INIS)

Venegas, R.; Labenski de Kanter, F.; Acebal, S.; Grassi, R.; Rueda, E.H.; Aguirre, M.E.; Saragovi, C.

1994-01-01

Bahia Blanca (Argentina) soils, in particular entisols, are studied by Moessbauer spectroscopy. X-ray diffraction and scanning electron microscopy are used to characterize the samples. Samples were treated with different chemical iron extraction methods, in order to determine relative Fe o and Fe d fractions. The Fe o /Fe d ratios are obtained and the relative effect of iron extraction treatment on spectra components are determined. In addition, the effect of extraction procedures, dithionite-citrate-bicarbonate and oxalate, in the residual soil fraction are analyzed. (orig.)

Moessbauer spectroscopy on the reaction center of Rhodopseudomonas viridis

International Nuclear Information System (INIS)

Frolov, E.; Goldanskii, V.I.; Birk, A.; Parak, F.; Fritzsch, G.; Sinning, I.; Michel, H.

1992-01-01

Proteins called 'reaction centers' (RC) can be isolated from many photosynthetic bacteria. They have one non-heme iron in a quinone acceptor region. The RC of Rhodopseudomonas viridis contains an additional tightly bound tetra-heme cytochrome c subunit. The electronic configuration of both cytochrome and the non-heme iron has been studied in the crystallized protein by Moessbauer spectroscopy at different redox potentials, pH-values, and with an addition of o-phenanthroline. At high potentials (E h =+500 mV) all heme irons are in the low spin Fe 3+ -state, and at low potential (E h = 1 50 mV) they are low spin Fe 2+ with the same Moessbauer parameters for all hemes independent of pH. Redox titrations change the relative area of the reduced and oxidized states in agreement with other methods. The non-heme iron shows a high spin Fe 2+ configuration independent of E h and pH with parameters comparable to those of Rhodopseudomonas sphaeroides. Surprisingly, there is strong evidence for another non-heme iron species in part of the molecules with a Fe 2+ low spin configuration. Incubation with o-phenanthroline decreases the relative Fe 2+ hs-area and increases the contribution of Fe 2+ ls-area. Above 210 K the mean square displacement, 2 >, of the RC-crystals increases more than linearly with temperature. This may be correlated with the increase of the electron transfer rate and indicates that intramolecular mobility influences the functional activity of a protein. (orig.)

Nuclear gamma resonance absorption (Moessbauer) spectroscopy as an archaeometric technique to assess chemical states of iron in a Tupiguarani ceramic artifact from Corinto, Minas Gerais, Brazil

International Nuclear Information System (INIS)

Floresta, D.L.; Ardisson, J.D.; Fagundes, M.; Fabris, J.D.

2013-01-01

Archaeological ceramics of Tupiguarani Tradition are found in many parts throughout the Brazilian territory and have many similarities. Fragments of Tupiguarani pottery found in the archaeological site known as Beltrao, in the municipality of Corinto, state of Minas Gerais, were identified and collected by researchers of the LAEP/UFVJM, in Diamantina, also in Minas Gerais. A selected fragment of about 15 mm-thick, with a color gradation across the ceramic wall ranging from red, on one side, grayish in the middle and orange on the opposite side, was transversely cut and a series of subsamples of powdered materials were collected from different depths across the wall, in layer segments of ∼3 mm, from the orange side. These powdered subsamples were analyzed with X-ray fluorescence and diffraction spectroscopy and 57 Fe Moessbauer spectroscopy at room temperature (298 K) and at 80 K. According to the XRF results, the elementary composition does not clearly vary with the depth in the sample. The powder XRD analysis revealed the occurrence mainly of quartz and muscovite. Results of 57 Fe Moessbauer spectroscopy reveal that hematite is the magnetically ordered phase. An Fe 2+ component appears for the grayish subsample. According to these results, the red subsample seems to be the external part of the pottery, representing the side that had direct contact with fire used to burn the precursor clay in air for this primitive ceramics preparation. The grayish middle layer is probably due to burning clay mixed with some ashes containing residual carbon, under milder temperature than on the external . (author)

Moessbauer studies of the structural phase transitions in RbFeF4

International Nuclear Information System (INIS)

Baumeler, Hp.; Keller, H.; Kuendig, W.; Savic, I.M.; Wanklyn, B.M.

1984-01-01

RbFeF 4 exhibits two structural phase transitions (SPT), namely a first-order transition at 381 K and a second-order transition at 417 K. A detailed 57 Fe Moessbauer investigation of these SPT is presented. At pronounced discontinuities in the quadrupole splitting and the recoil-free fraction are observed, whereas at 417 K both quantities vary continuously with temperature. Both SPT are also seen in the area ratio of the single crystal quadrupole lines which reflects the tilting of the FeF 6 octahedra with respect to the c-axis. However, no noticeable indication of the SPT is found in the center shift. (Auth.)

Evaluation of accidental coincidences for time-differential Moessbauer-spectroscopy

International Nuclear Information System (INIS)

Alflen, M.; Meyer, W.

1995-01-01

The accidental coincidences of a measuring system based on time-to-amplitude conversion are considered in some detail for the case of low starting and high stopping rates. Two types of accidental coincidences are distinguished, those carrying time information and those without time information. Neglecting any deadtime effects of the detectors, analytical expressions for the calculation of the time distribution of the random coincidences are evaluated. The analytical expressions have been confirmed by Monte Carlo simulations. The procedure is applied to time-differential Moessbauer spectroscopy in order to extract the time spectra of true coincidences. The measured spectrum in a time channel turns out to be a superposition of the true spectrum (true coincidences), a time integral spectrum (random coincidences), and a weighted superposition of true spectra of other time channels (random but time carrying information). A measurement with a single line 57 Co/Rh-source and single line K[Fe(CN) 6 ].3H 2 O-absorber with stopping rates of 1 MBq shows agreement between the theoretical time-filtered spectra and the corrected measured spectra of true coincidences. ((orig.))

Moessbauer spectroscopy and additional study of neutron irradiated Cr-doped metallic glasses

International Nuclear Information System (INIS)

Miglierini, M.; Sitek, J.; Mihalik, M.; Zentko, A.

1990-01-01

Concentration and fluence dependent tendency of FeNiCrMoSiB metallic glass towards disordering as well as a decrease of the Curie temperature were revealed by Moessbauer and electron-positron annihilation spectroscopies and initial permeability measurements, respectively. The observed changes can be assigned to irradiation-induced defects resulting in fluctuations in chemical and/or topological short-range order. (orig.)

Site populations analysis of the Sm2(Co,Fe)17 alloys using Moessbauer spectroscopy

International Nuclear Information System (INIS)

Nagamine, L.C.C.M.

1990-01-01

Moessbauer measurements were carried out at room temperature for Sm 2 (Co 1-x Fe x ) 17 alloys with x=0,1 to 0,6 and Sm 2 (Co 0.9-v Fe v Cu 0.08 Zr 0.02 ) 8.35 , with v=0.23 to 0.27. All samples were characterized by x-ray diffraction. They showed rhombohedral structure of Th 2 Zn 17 type (R 3-bar m), where Fe atoms occupy four crystallographic sites. All spectra showed magnetic splitting and a high complexity resulting from the superposition of four Fe sites. Hyperfine parameters and site populations were obtained by least-squares fitting of the spectra. (author)

Moessbauer spectroscopy of locally inhomogeneous systems

International Nuclear Information System (INIS)

Rusakov, V. S.; Kadyrzhanov, K. K.

2004-01-01

Substances with characteristic local inhomogeneities - with different from position to position neighborhood and properties of like atoms - gain recently increased scientific attention and wide practical application. We would call a system locally inhomogeneous if atoms in the system are in non-equivalent atomic locations and reveal different properties. Such systems are, first of all, variable composition phases, amorphous, multi-phase, admixture, defect and other systems. LIS are most convenient model objects for studies of structure, charge, and spin atomic states, interatomic interactions, relations between matter properties and its local characteristics as well as for studies of diffusion kinetics, phase formation, crystallization and atomic ordering; all that explains considerable scientific interest in such LIS. Such systems find their practical application due to wide spectrum of useful, and sometimes unique, properties that can be controlled varying character and degree of local inhomogeneity. Moessbauer spectroscopy is one of the most effective methods for investigation of LIS. Local character of obtained information combined with information on cooperative phenomena makes it possible to run investigations impossible for other methods. Moessbauer spectroscopy may provide with abundant information on peculiarities of macro- and microscopic state of matter including that for materials without regular structure. At the same time, analysis, processing and interpretation of Moessbauer spectra for LIS (that are sets of a large amount of partial spectra) face considerable difficulties. Development of computer technique is accompanied with development of mathematical methods used for obtaining physical information from experimental data. The methods make it possible to improve considerably, with some available a priori information, effectiveness of the research. Utilization of up-to-date mathematical methods in Moessbauer spectroscopy requires not only adaptation

Moessbauer spectroscopy of some volcanic glasses from the Pampa Region, Cordoba, Argentina

International Nuclear Information System (INIS)

Saragovi-Badler, C.; Labenski, F.

1987-01-01

Moessbauer spectroscopy was applied to the study of volcanic glasses and closely associated clay minerals which were carefully separated from the sediments of the Pampa Region. The parameters of volcanic glass samples show the presence of a high content of Fe 2+ in octahedral coordination and some Fe 3+ in tetrahedral and octahedral coordination. No remarcable difference was found comparing with a 'pure' volcanic glass sample taken as a reference. In the clay samples the only clay mineral found was illite. (author) 7 refs

Moessbauer Spectroscopy in Materials Science

International Nuclear Information System (INIS)

2006-01-01

The publication in electronic form has been set up as proceedings of the conference dealing with applications of the Moessbauer spectroscopy in material science. Twenty-three abstracts and twenty-two presentations are included.

The Moessbauer spectroscopy in the characterization of atmospheric corrosion products; La espectroscopia Moessbauer en la caracterizacion de productos de corrosion atmosferica

Energy Technology Data Exchange (ETDEWEB)

Hernandez Torres, D; Leiva Ronda, P [Centro de Estudios Aplicados al Desarrollo Nuclear (CEADEN), La Habana (Cuba); Gomez, J; Ronda, M [Centro de Investigaciones del Petroleo, La Habana (Cuba)

1996-07-01

A study of corrosion products on mild steel formed after 1 and 5 years exposure in two industrial coastal weathering stations in the Bay from Matanzas City, Cuba, has been carried out. Structural analysis was conducted using mainly transmission Moessbauer Spectroscopy and the X-ray diffraction as complementary technique. The main phases found in the specimen exposed to high chloride containing environment were: lepidocrocite ({gamma}- FeOOH), goethite ({alpha}- FeOOH) and magnetite concentration was the lowest, the phases found were {gamma}- FeOOH and {alpha}- FeOOH, and the phase transformation proposed was {gamma}- FeOOh -> {alpha}- Fe-OOH. In this station were found also amorphous corrosion products. There amorphous phases could be responsible for the lowest levels of corrosion on steel in this station.

Moessbauer study on the formation process of Fe-K composition in iron-based catalyst for dehydrogenation of ethylbenzene

International Nuclear Information System (INIS)

Jiang Keyu; Zhao Zhenjie; Yang Xielong

2001-01-01

Fe-K spinel structure is the predecessor of active phase of potassium promoted iron-based catalyst for dehydrogenation of ethylbenzene. Moessbauer spectroscopy has been used to study the formation process of Fe-K spinel structure which depends on the catalyst composition and preparing condition. The results may prove useful for production of industrial catalyst

Gamma-X-ray coincidence Moessbauer spectroscopic study of the aftereffects in sulfate hydrates

International Nuclear Information System (INIS)

Kobayashi, T.; Makita, T.; Fukumura, K.

1990-01-01

The anomalous charge states formed after the electron capture decay of 57 Co in FeSO 4 .H 2 O and FeSO 4 .7H 2 O are investigated using the conventional Moessbauer emission spectroscopy and a gamma-X ray coincidence method. This method is based on the idea that a Moessbauer spectrum observed with the coincidence technique only when K-X rays are emitted is reflected by isolated events with a reduced influence of the Auger-electron self-irradiation. The formation of the anomalous electronic and structural configuration is attributed to the self-radiolysis of the H 2 O and SO 4 2- ligands in the nearest and the second nearest coordination shells around the decaying atom. (orig.)

Spin crossover studies in cationic complexes of iron by using Moessbauer spectroscopy

International Nuclear Information System (INIS)

Vadera, S.R.; Kumar, N.

1990-01-01

The spin transition in two new cationic complexes of iron, i.e. iron bipyridine formate, [Fe(bipy) 3 ](HCOO) 2 .5(HCOOH) and iron bipyridine tetrafluoro borate, [Fe(bipy) 3 ](BF 4 ) 2 .2H 2 O were studied by Moessbauer spectroscopy. From quadrupole splitting values, it was established that at different temperatures both complexes show the coexistence of both high spin state and low spin state at 300 K, while complete transformation to low spin state occurs at 77 K. Both compounds were prepared by electrochemical technique. (author) 12 refs.; 1 fig.; 1 tab

Moessbauer spectroscopy with a high velocity resolution: advances in biomedical, pharmaceutical, cosmochemical and nano technological research

International Nuclear Information System (INIS)

Oshtrakha, M.I.; Semionkina, V.A.

2011-01-01

. Characteristics of this system demonstrated a high stability, precision and accuracy in the measurement of Moessbauer spectra in 4096 channels. In spite of substantial increase in the measurement time, spectra measured with a high velocity resolution permitted to obtain Moessbauer hyperfine parameters with systematic errors at least 8 times less than in the case of spectra measurement in 512 channels as well as to fit complicated Moessbauer spectra with better quality. Various applications of Moessbauer spectroscopy with a high velocity resolution demonstrated new possibilities of technique. Biomedical applications. New results were obtained in the study of human liver ferritin, its pharmaceutically important models as well as liver and spleen tissues from normal and leukemia chicken; in comparative study of various human and animals' normal oxyhemoglobins and oxyhemoglobins from patients; in the study of iron containing pharmaceutical products. Cosmochemical applications. In the study of various meteorites new results were obtained in analysis of Fe-Ni alloys with variations in Ni concentration, in the study of silicate phases and Fe-Ni phosphides with crystallographically non-equivalent sites for Fe. Nanotechnological applications. New results were obtained in the study of cupric ferrite nanoparticles with tin oxide adding as well as in the study of ferric oxide nanoparticles developed for magnetic fluids for biomedical purposes. (author)

Moessbauer spectroscopic study of Fe{sup II}-doped sulphonated poly(ether-urethane)-styrene-acrylate copolymer

Energy Technology Data Exchange (ETDEWEB)

Kamnev, A. A. [Russian Academy of Sciences, Institute of Biochemistry and Physiology of Plants and Microorganisms (Russian Federation); Grigoryeva, O. P.; Fainleib, A. M. [National Academy of Sciences of Ukraine, Institute of Macromolecular Chemistry (Ukraine); Kuzmann, E., E-mail: kuzmann@ludens.elte.hu [Eoetvoes Lorand University, Institute of Chemistry (Hungary)

2013-04-15

Thermoplastic linear ionomer based on sulphonated poly(ether-urethane)-styrene-acrylate copolymer, doped with natural Fe{sup 2 + }, was studied by Moessbauer spectroscopy at T = 78 and 290 K to monitor the chemical state of Fe species. The Fe{sup 2 + } added to aqueous suspension of the system was only partly oxidised in the course of polymer film preparation and drying in air. The oxidised part comprised a magnetic phase ({approx}19 % of total Fe both at T = 78 and 298 K) and a quadrupole doublet ({approx}40 %), while Fe{sup II} (over 40 %) stabilised in two types of microenvironments.

/sup 57/Co Moessbauer study of the recovery process of electron-irradiated gold

Energy Technology Data Exchange (ETDEWEB)

Tanaka, I.; Nasu, S.; Fujita, F.E.

1988-03-15

The recovery process of Au--10-at. ppm-Co alloy after electron irradiation at 78 K was investigated by means of /sup 57/Co emission Moessbauer spectroscopy. Three satellite lines were observed and assigned to the small interstitial(I)--Co complexes, the micro-I-loops containing Co atoms and the divacancy-Co complexes, respectively. A fairly strong binding energy between the interstitial and Co atoms in small I-Co complexes, most probably larger than 0.2 eV, was deduced

Moessbauer studies of the structural phase transitions in RbFeF/sub 4/

Energy Technology Data Exchange (ETDEWEB)

Baumeler, Hp.; Keller, H.; Kuendig, W.; Savic, I.M.; Wanklyn, B.M.

1984-03-20

RbFeF/sub 4/ exhibits two structural phase transitions (SPT), namely a first-order transition at 381 K and a second-order transition at 417 K. A detailed /sup 57/Fe Moessbauer investigation of these SPT is presented. At pronounced discontinuities in the quadrupole splitting and the recoil-free fraction are observed, whereas at 417 K both quantities vary continuously with temperature. Both SPT are also seen in the area ratio of the single crystal quadrupole lines which reflects the tilting of the FeF/sub 6/ octahedra with respect to the c-axis. However, no noticeable indication of the SPT is found in the center shift.

Molecular Sensors for Moisture Detection by Moessbauer Spectroscopy

International Nuclear Information System (INIS)

Renz, F.; Souza, P. A. de; Klingelhoefer, G.; Goodwin, H. A.

2002-01-01

A parameter of importance in various industrial and commercial applications is sensitivity to moisture. A new class of molecular sensors which enable the qualitative and quantitative determination of air moisture (high selectivity and sensitivity) by application of Moessbauer spectroscopy as the probe technique has been investigated. The electronic properties of the iron-containing sensor depend upon the presence of moisture which is taken up by it and this process is accompanied by a change in electronic spin ground state which can be detected by Moessbauer spectroscopy. The sensor is suitable for in-field and industrial application using the recently developed Moessbauer spectrometer MIMOS II. Possible suitability for the detection of moisture in extraterrestrial environments is considered.

Moessbauer study of ancient iron smelting slag in Japan

International Nuclear Information System (INIS)

Nakanishi, A.

2008-01-01

For an investigation of the ancient iron manufacturing technique, a reproducing experiment was carried out by archaeologists, where ancient type of iron smelting furnace was built and iron sand with high titanium contents was used as the raw material. During the operation of furnace, a large amount of slag flowed away from the furnace. In order to investigate the possibility for the estimation about the operative condition of furnace and the raw material, 57 Fe Moessbauer spectroscopy was applied for characterizing these slags and it was found that these slags mainly consisted of ferropseudobrookite (FeTi 2 O 5 ).

Deconvolution of Moessbauer spectra using Voigt functions; Deconvolucion de espectros Moessbauer empleando funciones Voigt

Energy Technology Data Exchange (ETDEWEB)

Flores Ll, H J

1990-08-15

The form of the resonance line in Moessbauer spectroscopy is a form of Lorentzian line, but this form of line it enlarges due to several effects: finite thickness of the absorber, instrumental instability, diffusion of Co{sup 57} in crystals and fluctuations in the environment of the emitting nucleus. To take into account this effects it has been used as form of line in Moessbauer spectroscopy the Voigt function that is the convolution of a Lorentzian and a Gaussian. (Author)

Moessbauer study of (Fe1-x Cu x )4N (0.05≤x≤0.15) films

International Nuclear Information System (INIS)

El Khiraoui, S.; Sajieddine, M.; Vergnat, M.; Bauer, Ph.; Mabrouki, M.

2007-01-01

In this work, we have prepared nitrogenated Fe 1- x Cu x alloys by reactive evaporation under a flow of nitrogen ions. After annealing, X-ray diffraction shows that we have synthesized the γ'-(Fe 1- x Cu x ) 4 N (0.05≤x≤0.15) compounds. The films were investigated by Moessbauer spectroscopy. The crystallographic structure and the respective positions of the Fe and Cu atoms in the compounds have been determined

Conversion electron Moessbauer spectroscopy of plasma immersion ion implanted H13 tool steel

International Nuclear Information System (INIS)

Terwagne, G.; Hutchings, R.

1994-01-01

Conversion electron Moessbauer spectroscopy (CEMS) has been used to investigate nitride formation in AISI-H13 tool steel after treatment by plasma immersion ion implantation (PI 3 ) at 350 C. With only slight variation in the plasma conditions, it is possible to influence the kinetics of nitride precipitation so as to obtain nitrogen concentrations that range from those associated with ε-Fe 2 N through ε-Fe 3 N to γ'-Fe 4 N. The CEMS results enable a more definite identification of the nitrides than that obtained by glancing-angle X-ray diffraction and nuclear reaction analysis alone. (orig.)

Early Pottery Making in Northern Coastal Peru. Part I: Moessbauer Study of Clays

International Nuclear Information System (INIS)

Shimada, I.; Haeusler, W.; Hutzelmann, T.; Wagner, U.

2003-01-01

We report on an investigation of several ancient clays which were used for pottery making in northern coastal Peru at a kiln site from the Formative period (ca. 2000-800 BC) in the Poma Canal and at a Middle Sican pottery workshop in use between ca. AD 950 and 1050 at Huaca Sialupe in the lower La Leche valley. Neutron activation analysis, 57 Fe Moessbauer spectroscopy and X-ray diffraction were used for the characterisation of the clays. The changes that occur in iron-bearing compounds in the clays depending on the kiln atmosphere and on the maximum firing temperature were studied by Moessbauer spectroscopy and X-ray diffraction. Laboratory firing series under varying controlled conditions were performed to obtain a basic understanding of the different reactions taking place in the clays during firing. The results can be used as models in the interpretation of the Moessbauer spectra observed in ancient ceramics from the same context.

Moessbauer study of amorphous Fe-P alloys

International Nuclear Information System (INIS)

Takacs, L.; Toth-Kadar, E.

1981-01-01

Preliminary Moessbauer results are represented on electrodeposited Fe-P amorphous alloys. Very broad hyperfine field distributions and relatively large isomer shifts have been found. Problems worth of further investigation are discussed in details. (author)

Moessbauer study of Fe-Al disordered alloys near the critical concentration

International Nuclear Information System (INIS)

Bohorquez, A.; Tabares, J.A.; Perez Alcazar, G.A.; Gancedo, J.R.

1994-01-01

Disordered bcc Fe 1-q Al q alloys in the composition range 0.5≤q≤0.6 were studied by Moessbauer effect measurements. The Moessbauer spectra at 300 K of all the samples consist of two paramagnetic sites, one is a singlet and the other a doublet with quadrupole splitting. The results can be interpreted by considering that the sites of this disordered system are arranged near the configurations of the Fe and Al sites of the Fe-Al ordered system. (orig.)

Moessbauer Spectroscopy: Elegance and versatility in chemical diagnostics

Energy Technology Data Exchange (ETDEWEB)

Guetlich, Philipp; Garcia, Yann, E-mail: guetlich@uni-mainz.d [Unite de Chimie des Materiaux Inorganiques et Organiques, Departement de Chimie, Universite Catholique de Louvain, Place L. Pasteur 1, 1348 Louvain la Neuve (Belgium)

2010-03-01

Dedicated to Professor Rudolf Ludwig Moessbauer on the occasion of his 80th birthday. Soon after the discovery of the recoilless nuclear resonance fluorescence by Rudolf L. Moessbauer some fifty years ago a new spectroscopic technique developed quickly on the basis of this resonance phenomenon as an excellent tool for the investigation of materials through electric and magnetic hyperfine interactions between electrons and suitable Moessbauer nu-clides. Many disciplines of solid state research have benefited from applications of the new tool for non-destructive phase analysis. Chemists in particular have recognized the information that can be derived from Moessbauer spectra regarding oxidation and spin state, molecular symmetry, bonding properties, magnetism, dynamic phenomena such as spin state switching, electronic transfer processes and other phase fluctuations to name a few. This Keynote Lecture presents highlights of chemical applications of Moessbauer spectroscopy selected from work during the past five decades which will demonstrate the elegance and versatility of the technique in the hands of (not only) chemists, but materials scientists in the broadest sense. The retrospect begins with studies in the early sixties on simple oxides and coordination compounds, where Moessbauer spectroscopy played a decisive role in solving unanswered questions, and concludes with fascinating current discoveries on the Planet Mars and most recent developments in the use of synchrotron radiation for nuclear resonance scattering (NFS, NIS).

Thermal treatment of the Fe{sub 78}Si{sub 9}B{sub 13} alloy in it amorphous phase studied by means of Moessbauer spectroscopy; Tratamiento termico de la aleacion Fe{sub 78}Si{sub 9}B{sub 13} en su fase amorfa estudiado por medio de la espectroscopia Moessbauer

Energy Technology Data Exchange (ETDEWEB)

Cabral P, A. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Lopez, A.; Garcia S, F. [Facultad de Ciencias, UAEM, 50000 Toluca, Estado de Mexico (Mexico)

2003-07-01

The magnetic and microhardness changes, dependents of the temperature that occur in the Fe{sub 78}Si{sub 9}B{sub 13} alloy in it amorphous state were studied by means of the Moessbauer spectroscopy and Vickers microhardness. According to the Moessbauer parameters and in particular that of the hyperfine magnetic field, this it changes according to the changes of the microhardness; i.e. if the microhardness increases, the hyperfine magnetic field increases. The registered increment of hardness in the amorphous state of this alloy should be considered as anomalous, according to the prediction of the Hall-Petch equation, the one that relates negative slopes with grain sizes every time but small. (Author)

Moessbauer spectroscopic studies of iron-storage proteins

Energy Technology Data Exchange (ETDEWEB)

St. Pierre, T.G.

1986-01-01

/sup 57/Fe Moessbauer spectroscopy was used to study iron storage proteins. Various cryostats and a superconducting magnet were used to obtain sample environment temperatures from 1.3 to 200K and applied magnetic fields of up to 10T. The Moessbauer spectra of ferritins isolated from iron-overloaded human spleen, limpet (Patella vulgata), giant limpet (Patella laticostata) and chiton (Clavarizona hirtosa) hemolymph, and bacterial (Pseudomonas aeruginosa) cells are used to gain information on the magnetic ordering- and superparamagnetic transition temperatures of the microcrystalline cores of the proteins. Investigations were made about the cause of the difference in the magnetic anisotropy constants of the cores of iron-overloaded human spleen ferritin and hemosiderin. Livers taken from an iron-overloaded hornbill and artificially iron-loaded rats showed no component with a superparamagnetic transition temperature approaching that of the human spleen hemosiderin.

Moessbauer effect in pure and impurity doped FeSi2

International Nuclear Information System (INIS)

Blaauw, C.; Hanson, H.; Woude, F. van der

1975-01-01

Numerical values of the calculated and experimentally determined Moessbauer parameters for pure β-FeSi 2 and α-FeSi 2 are given. Temperature dependence of isomer shift and quadrupole splitting for the two Fe positions in β-FeSi 2 is presented. For α-FeSi 2 only average values are given. Spectra of Co- and Al-doped FeSi 2 recorded at 80, 293, 557 and 788 K were analyzed in the same manner as those of undoped FeSi 2 . The average values of isomer shift and quadrupole splitting in Co- and Al-doped β-FeSi 2 (α-Fesi 2 ) were compared to those found in undoped β-FeSi 2 (α-FeSi 2 ). All data were based on the room temperature spectra. Changes in Moessbauer parameters of doped samples relative to undoped ones were generally small, being of the order of hundredths of mm/sec. (Z.S.)

Structural, magnetic and thermal properties of CaMn0.9957Fe0.01O3-δ

International Nuclear Information System (INIS)

Przewoznik, J.; Chmist, J.; Kolwicz-Chodak, L.; Tarnawski, Z.; Kapusta, Cz.; Kolodziejczyk, A.

2007-01-01

The polycrystalline CaMn 0.99 57 Fe 0.01 O 3-δ compound was studied using powder X-ray diffraction, 57 Fe Moessbauer spectroscopy, ac susceptometry, dc magnetometry, specific heat and electrical resistivity measurements. X-ray diffraction measurements performed between 70 and 300 K show a thermal expansion anomaly at the Neel temperature. A weak ferromagnetic component and a spin-glass behaviour below Neel temperature are found in magnetic measurements. The Moessbauer spectroscopy measurements performed between 30 and 300 K provided the Neel temperature value of 118 K, the same as obtained from dc magnetisation and close to that derived from the specific heat (119 K). The temperature evolution of the Fe hyperfine field was analysed within a molecular field model and revealed equal strengths of the Fe-Mn and Mn-Mn exchange interactions in this compound

Moessbauer determination of magnetic structure of Fe3BO6 crystal

International Nuclear Information System (INIS)

Kovalenko, P.P.; Labushkin, V.G.; Ovsepyan, A.K.; Sarkisov, Eh.R.; Smirnov, E.V.; Prokopov, A.R.; Seleznev, V.N.

1984-01-01

The magnetic structure of a Fe 3 BO 6 crystal belonging to space group Dsub(2h)sup(16)(Psub(nma)) is determined by the Moessbauer γ-radiation diffraction. The bragg reflection (700) of Moessbauer 14.4 keV γ-quanta from the Fe 3 BO 6 monocrystal has been studied experimentally. A high sensitivity of the interference of γ-quantum diffraction scattering on Fe nuclei being in crystallographically non-equivalent 8d- and 4s-positions to the type of magnetic ordering in the crystal is used for determination of the magnetic structure. Agreement of the experimental results with the theoretical calculations, conducted for types of magnetic ordering resolved by the symmetry of the crystal, permitted to reliably determine the magnetic structure of this compound. The results obtained confirm the data of neutrondiffraction studies on magnetic ordering in Fe 3 BO 6 . Advantages of the Moessbauer-diffraction study, as compared to the magnetic neutrondiffraction method, in particular, for investigation of crystals, in which the hyperfine magnetic fields on Fe nuclei have different values, are revealed and discussed in detail

Inelastic scattering in condensed matter with high intensity Moessbauer radiation

International Nuclear Information System (INIS)

Yelon, W.B.; Schupp, G.

1993-02-01

The QUEGS facility at MURR has produced a number of new results and demonstrated the range of potential applications of high resolution, high intensity Moessbauer scattering. This work has been carried out by both MU and Purdue researchers and includes published results on Na, W, pentadecane, polydimethylsiloxane and other systems, manuscripts submitted on alkali halides (Phys. Rev. B) and accurate Moessbauer lineshape measurements (Phys. Rev. C), and manuscripts in preparation on glycerol, NiAl and Moessbauer spectra obtained by modulating a scattering crystal. Recently, new collaborations have been initiated which will substantially enhance our efforts. These are with W. Steiner (Vienna), G. Coddens (Saclay), and R. D. Taylor (Los Alamos). Steiner is experienced with Fe-57 Moessbauer scattering, while Coddens specializes in quasielastic neutron scattering; both of these areas naturally complement our work. R. D. Taylor has pioneered Moessbauer spectroscopy from the time of its discovery and has already made important contributions to our study of lattice dynamics and superconductivity for lead alloyed with small quantities of tin. At the same time, a significant instrument upgrade is underway, funded in part by the DOE-URIP program

Moessbauer spectroscopy of iron in clay minerals

International Nuclear Information System (INIS)

Raclavsky, K.; Sitek, J.; Lipka, J.

1975-01-01

Selected pure clay minerals predominantly of Czechoslovak origin were studied, such as montmorillonite, nontronite, beidellite, glauconite, seladonite, illite, vermiculite, saponite, palygorskite, goethite. Moessbauer measurements were performed at room temperature with a 57 Co in Pd source. The spectra were fitted by the least square method. The parameters of the measured Moessbauer spectra are given. The values of isomer shifts, quadrupole splittings and line widths were obtained with an error of +- 0.03 mm/sec. (Z.S.)

57Fe Mössbauer spectroscopy used to develop understanding of a diamond preservation index model

International Nuclear Information System (INIS)

Yambissa, M. T.; Forder, S. D.; Bingham, P. A.

2016-01-01

57 Fe Mössbauer spectroscopy has provided precise and accurate iron redox ratios Fe 2+ /Fe 3+ in ilmenite, FeTiO 3 , found within kimberlite samples from the Catoca and Camatxia kimberlite pipes from N.E. Angola. Ilmenite is one of the key indicator minerals for diamond survival and it is also one of the iron-bearing minerals with iron naturally occurring in one or both of the oxidation states Fe 3+ and Fe 2+ . For this reason it is a good indicator for studying oxygen fugacities (fO 2 ) in mineral samples, which can then be related to iron redox ratios, Fe 2+ /Fe 3+ . In this paper we demonstrate that the oxidation state of the ilmenite mineral inclusion from sampled kimberlite rock is a key indicator of the oxidation state of the host kimberlite assemblage, which in turn determines the genesis of diamond, grade variation and diamond quality. Ilmenite samples from the two different diamondiferous kimberlite localities (Catoca and Camatxia) in the Lucapa graben, N.E. Angola, were studied using Mössbauer spectroscopy and X-Ray Diffractometry, in order to infer the oxidation state of their source regions in the mantle, oxygen partial pressure and diamond preservation conditions. The iron redox ratios, obtained using Mössbauer spectroscopy, show that the Catoca diamond kimberlite is more oxidised than kimberlite found in the Camatxia pipe, which is associated within the same geological tectonic structure. Here we demonstrate that 57 Fe Mössbauer spectroscopy can assist geologists and mining engineers to effectively evaluate and determine whether kimberlite deposits are economically feasible for diamond mining.

Some antarctic soil cores from Wood Bay characterised by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Bertelle, M.; Leotta, G.; Calogero, S.; Constantinescu, S.; Oddone, M.

1999-01-01

Marine, lacustrine and terrestrial soil cores, sampled in a restricted area of Wood Bay in Antarctica, were characterised by 57 Fe Moessbauer spectroscopy. The results of X-ray diffraction and instrumental neutron activation analysis are shortly discussed too. The soils, formed by mechanical disaggregation and weathering of rocks of volcanic origin from Mt. Melbourne, consist of alkaline feldspars, olivines, augitic clinopyroxenes, and iron oxides such as haematite, goethite, and magnetite. Lacustrine and terrestrial soils are richer in clinopyroxenes whereas marine soils are richer in olivines. This finding shows that the soils retain a content in olivines and clinopyroxenes comparable to that found in the parent lava outcropped from Mt. Melbourne volcano. The soils appear at the initial stage of weathering. Two main weathering effects are observed: 1. atmospheric oxygen determines the oxidation of the iron(II) present in olivines and clinopyroxenes and the neo-formed iron(III) is mainly retained in silicate sites as structural iron(III); 2. a part of magnetite, present as a primary constituent of the volcanic rocks, is oxidised to bulk haematite and goethite. (authors)

The big and little of fifty years of Moessbauer spectroscopy at Argonne

International Nuclear Information System (INIS)

Westfall, C.

2005-01-01

Using radioactive materials obtained by chance, a turntable employing gears from Heidelberg's mechanical toy shops, and other minimal equipment available in post World War II Germany, in 1959 Rudolf Moessbauer confirmed his suspicion that his graduate research had yielded ground-breaking results. He published his conclusion: an atomic nucleus in a crystal undergoes negligible recoil when it emits a low energy gamma ray and provides the entire energy to the gamma ray. In the beginning Moessbauer's news might have been dismissed. As Argonne nuclear physicist Gilbert Perlow noted: ''Everybody knew that nuclei were supposed to recoil when emitting gamma rays--people made those measurements every day''. If any such effect existed, why had no one noticed it before? The notion that some nuclei would not recoil was ''completely crazy'', in the words of the eminent University of Illinois condensed matter physicist Frederich Seitz. Intrigued, however, nuclear physicists as well as condensed matter (or solid state) physicists in various locations--but particularly at the Atomic Energy Research Establishment at Harwell in Britain and at Argonne and Los Alamos in the U.S.--found themselves pondering the Moessbauer spectra with its nuclear and solid state properties starting in late 1959. After an exciting year during which Moessbauer's ideas were confirmed and extended, the physics community concluded that Moessbauer was right. Moessbauer won the Nobel Prize for his work in 1961. In the 1960s and 1970s Argonne physicists produced an increasingly clear picture of the properties of matter using the spectroscopy ushered in by Moessbauer. The scale of this traditional Moessbauer spectroscopy, which required a radioactive source and other simple equipment, began quite modestly by Argonne standards. For example Argonne hosted traditional Moessbauer spectroscopy research using mostly existing equipment in the early days and equipment that cost $100,000 by the 1970s alongside work at

The big and little of fifty years of Moessbauer spectroscopy at Argonne.

Energy Technology Data Exchange (ETDEWEB)

Westfall, C.

2005-09-20

Using radioactive materials obtained by chance, a turntable employing gears from Heidelberg's mechanical toy shops, and other minimal equipment available in post World War II Germany, in 1959 Rudolf Moessbauer confirmed his suspicion that his graduate research had yielded ground-breaking results. He published his conclusion: an atomic nucleus in a crystal undergoes negligible recoil when it emits a low energy gamma ray and provides the entire energy to the gamma ray. In the beginning Moessbauer's news might have been dismissed. As Argonne nuclear physicist Gilbert Perlow noted: ''Everybody knew that nuclei were supposed to recoil when emitting gamma rays--people made those measurements every day''. If any such effect existed, why had no one noticed it before? The notion that some nuclei would not recoil was ''completely crazy'', in the words of the eminent University of Illinois condensed matter physicist Frederich Seitz. Intrigued, however, nuclear physicists as well as condensed matter (or solid state) physicists in various locations--but particularly at the Atomic Energy Research Establishment at Harwell in Britain and at Argonne and Los Alamos in the U.S.--found themselves pondering the Moessbauer spectra with its nuclear and solid state properties starting in late 1959. After an exciting year during which Moessbauer's ideas were confirmed and extended, the physics community concluded that Moessbauer was right. Moessbauer won the Nobel Prize for his work in 1961. In the 1960s and 1970s Argonne physicists produced an increasingly clear picture of the properties of matter using the spectroscopy ushered in by Moessbauer. The scale of this traditional Moessbauer spectroscopy, which required a radioactive source and other simple equipment, began quite modestly by Argonne standards. For example Argonne hosted traditional Moessbauer spectroscopy research using mostly existing equipment in the early days and

Iron chelates: a challenge to chemists and Moessbauer spectroscopists

Energy Technology Data Exchange (ETDEWEB)

Homonnay, Z., E-mail: homonnay@chem.elte.hu; Szilagyi, P. A.; Vertes, A. [Eoetvoes Lorand University, Laboratory of Nuclear Chemistry, Institute of Chemistry (Hungary); Kuzmann, E. [Hungarian Academy of Sciences, Department of Nuclear Chemistry, Chemical Research Center (Hungary); Sharma, V. K. [Florida Institute of Technology (United States); Molnar, G.; Bousseksou, A. [CNRS UPR-8241, Laboratoire de Chimie de Coordination (France); Greneche, J.-M. [Universite du Maine, Laboratoire de Physique de l' Etat Condense, CNRS UMR 6087 (France); Brausam, A.; Meier, R.; Eldik, R. van [University of Erlangen-Nuernberg, Institute for Inorganic Chemistry (Germany)

2008-02-15

The speciation of iron in aqueous solutions containing Fe{sup 3+} and selected chelates such as EDTA, EDDA, CDTA and HEDTA has been studied using transmission {sup 57}Fe Moessbauer spectrometry in frozen solutions. The protonation of various complexes as well as binuclear complex formation could be detected as a function of pH. Autoreduction of Fe{sup 3+} to Fe{sup 2+} was observed in several cases. Reaction with hydrogen peroxide proved to be rather different for the four ligands, while the dihapto complex [XFe({eta}{sup 2}-O{sub 2})]{sup 3-} had surprisingly identical Moessbauer parameters for X = EDTA, CDTA or HEDTA. Paramagnetic spin relaxation observed in the Moessbauer spectra was found to be strongly influenced by the identity of the chelating ligand, despite the basically spin-spin origin of the phenomenon.

Analysis of magnetic compounds of Kosice meteorite using Moessbauer spectrometry

International Nuclear Information System (INIS)

Dekan, J.; Sitek, J.; Sedlackova, K.

2013-01-01

Meteorite fall was observed by the town Kosice in Slovakia in February 2010. The fall itself was imaged by three security video cameras from Hungary. Detailed bolide light curves were obtained through clouds by radiometers on seven cameras of the European Fireball Network. Records of sonic waves were found on six seismic and four infrasonic stations. chondrites in various works. Due to the high abundance of iron in the solar system and its chemical and physical properties, we can gain insight into the formation and evolution of planets through the study of iron compounds in the planetary bodies. These kinds of analyses can bring important knowledge about phases and compounds formed in extraterrestrial conditions, which have another features than their terrestrial analogues. The "5"7Fe Moessbauer spectroscopy is one of the most sensitive methods for such studies. In this work Moessbauer spectroscopy will be used for phase analysis of iron bearing compounds with the aim to identify magnetic fractions using magnetic separation. (authors)

In situ iron-57 Moessbauer spectroscopic investigations of the effect of titania surface area on the reducibility of titania-supported iron oxide

International Nuclear Information System (INIS)

Berry, F.J.; Du Hongzhang

1990-01-01

Iron-57 Moessbauer spectroscopy has been used to monitor the reducibility in hydrogen of iron oxides supported on titania of differing surface areas. The results show that although Fe 3+ in the iron oxide supported on low surface area titania (11 m 2 g -1 ) is not amenable to facile reduction at low temperatures, complete reduction to metallic iron is achieved by treatment at 600deg C. The data also show that the extent of reduction at elevated temperatures exceeds that which is obtained on similar silica- and alumina-supported systems. Fe 3+ in iron oxide supported on higher surface area titania (50 m 2 g -1 and 240 m 2 g -1 ) is partially reduced in hydrogen at 235deg C to Fe 2+ but fails to attain complete reduction to the metallic state following treatment at 600deg C. The results are related to the different dispersions of iron oxide which can be attained on titania of differing surface area and the consequent interactions between the support and the supported phases. (orig.)

Deconvolution of Moessbauer spectra using Voigt functions

International Nuclear Information System (INIS)

Flores Ll, H.J.

1990-08-01

The form of the resonance line in Moessbauer spectroscopy is a form of Lorentzian line, but this form of line it enlarges due to several effects: finite thickness of the absorber, instrumental instability, diffusion of Co 57 in crystals and fluctuations in the environment of the emitting nucleus. To take into account this effects it has been used as form of line in Moessbauer spectroscopy the Voigt function that is the convolution of a Lorentzian and a Gaussian. (Author)

Investigation of microbial-mineral interactions by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Sawicki, J.A.; Brown, D.A.

1998-01-01

Moessbauer spectroscopy was used to investigate the reactions of microbes with iron minerals in aqueous solutions and as components of rocks in banded iron formations and granite. A microbial biofilm that formed on a wall of an excavated granite vault in a deep underground laboratory initiated this research. At the aerobic face of the biofilm, iron was found in a form of ferrihydrite; in the anaerobic face against the rock, iron was found as very small siderite particles. Laboratory incubations of the biofilm microbial consortium showed different mineral species could be formed. When the microbial consortium from the biofilm was incubated with magnetite grains, up to about 10% of the iron was altered in three weeks to hematite. The ability of the consortium to precipitate iron both as Fe 2+ and Fe 3+ in close proximity may have a bearing on the deposition of banded iron formations. These reactions could also be important in microbially induced corrosion

Moessbauer study of (Benzylideneacetone) Fe(Co)2L complexes with L=CO, phosphines and phosphites

International Nuclear Information System (INIS)

Vichi, E.J.S.; Stein, E.

1988-01-01

It is established that in iron complexes, both ligand-L-> Fe bonding and Fe -> L back bonding increase the s electron density at the iron nucleus (1), with a consequent decrease in the isomer shift (δ) obtained from the Moessbauer spectrum. Through θ-bonding, electrons are transferred from the ligand to the proper iron orbitals which have, at least, partial 4s character. Through Π-back bonding, d electrons of the metal are transferred to the proper orbitals of the ligand, decreasing the shielding of the metal 3s electrons. So, δ measures the effect of (θ+Π) bonding on s electron density at the iron nucleus. The quadrupole splitting (ΔE q ), which is related to the electric field gradient at the iron nucleus and involves only d or p electrons, measures the effect of (θ-Π) bonding. Here, the results of a Moessbauer spectroscopy study on title complexes are reported. (author)

Moessbauer study of LaFeAsO and F-doped superconductors in external magnetic fields

International Nuclear Information System (INIS)

Kitao, S; Kobayashi, Y; Higashitaniguchi, S; Kurokuzu, M; Saito, M; Seto, M; Mitsui, T; Kamihara, Y; Hirano, M; Hosono, H

2010-01-01

The iron-based F-doped superconductors LaFeAsO 1-x F x with a transition temperature of 24 K (for x = 0.07) and 26 K (x = 0.11) and its parent material LaFeAsO were studied using 57 Fe Moessbauer spectroscopy. Further investigation was carried out by applying external magnetic fields. F-doped superconductors showed a singlet pattern with no magnetic splitting throughout the temperature range from 4.2 to 298 K. On the other hand, magnetically-split spectra were observed in the parent LaFeAsO below the Neel temperature of about 140 K. The internal magnetic field reached 5.3 T at 4.2 K. The external magnetic fields up to 14 T were applied to the singlet phases, F-doped superconductors and the parent LaFeAsO above the Neel temperature. The induced magnetically-split spectra showed the internal magnetic fields with the comparable value to the applied fields. This fact confirmed that these singlet phases have the paramagnetic feature. The magnetic fields were also applied to the magnetically-ordered phase of LaFeAsO below the Neel temperature. The evolution of the spectra depending on the external magnetic fields was clearly explained by a model with two sublattice spins of the powdered antiferromagnet. This fact confirmed the magnetically-ordered phase is an antiferromagnet. The spin-flop field was also estimated by the model as about 26 T.

Moessbauer Spectroscopy study of Quimsachata Volcano materials

International Nuclear Information System (INIS)

Dominguez, A.G.B.

1988-01-01

It has been studied volcanic lava from Quimsachata Volcano in Pem. Moessbauer Spectroscopy, X-ray diffraction, electronic and optical microscopy allowed the identification of different mineralogical phases. (A.C.AS.) [pt

{sup 57}Fe Mössbauer spectroscopy used to develop understanding of a diamond preservation index model

Energy Technology Data Exchange (ETDEWEB)

Yambissa, M. T.; Forder, S. D.; Bingham, P. A., E-mail: p.a.bingham@shu.ac.uk [Sheffield Hallam University, Materials and Engineering Research Institute Faculty of Arts, Computing, Engineering and Sciences (United Kingdom)

2016-12-15

{sup 57}Fe Mössbauer spectroscopy has provided precise and accurate iron redox ratios Fe{sup 2+}/Fe{sup 3+} in ilmenite, FeTiO{sub 3}, found within kimberlite samples from the Catoca and Camatxia kimberlite pipes from N.E. Angola. Ilmenite is one of the key indicator minerals for diamond survival and it is also one of the iron-bearing minerals with iron naturally occurring in one or both of the oxidation states Fe{sup 3+} and Fe{sup 2+}. For this reason it is a good indicator for studying oxygen fugacities (fO{sub 2}) in mineral samples, which can then be related to iron redox ratios, Fe{sup 2+}/Fe{sup 3+}. In this paper we demonstrate that the oxidation state of the ilmenite mineral inclusion from sampled kimberlite rock is a key indicator of the oxidation state of the host kimberlite assemblage, which in turn determines the genesis of diamond, grade variation and diamond quality. Ilmenite samples from the two different diamondiferous kimberlite localities (Catoca and Camatxia) in the Lucapa graben, N.E. Angola, were studied using Mössbauer spectroscopy and X-Ray Diffractometry, in order to infer the oxidation state of their source regions in the mantle, oxygen partial pressure and diamond preservation conditions. The iron redox ratios, obtained using Mössbauer spectroscopy, show that the Catoca diamond kimberlite is more oxidised than kimberlite found in the Camatxia pipe, which is associated within the same geological tectonic structure. Here we demonstrate that{sup 57}Fe Mössbauer spectroscopy can assist geologists and mining engineers to effectively evaluate and determine whether kimberlite deposits are economically feasible for diamond mining.

Dedicated detectors for surface studies by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Bibicu, I.; Rogalski, M.S.; Nicolescu, G.

2001-01-01

Moessbauer spectroscopy is a nuclear resonance method largely utilized in solid state studies. Following resonant nuclear absorption, gamma radiations, conversion X-rays, conversion or Auger electrons are emitted. By detection of gamma radiations information about the sample as a whole are obtained while by detection of electrons or X radiation one obtains data on the surface layer. Our laboratory was among the firsts to produce and use flow gas proportional detectors for surface studies by Moessbauer spectroscopy. Four types of detectors were devised: - detectors for electron detection (90% He + 10% CH 4 ); - detectors for conversion X-ray detection (90% Ar + 10% CH 4 ); - detectors for electrons or internal conversion X rays; - detectors for simultaneous detection of electrons and conversion X rays emitted from the same source. All detectors allow simultaneous Moessbauer measurements both for surface and volume for a given sample. Details of construction are presented for the four types of detectors

A Moessbauer study on the interaction between biomolecular lipid membranes and ferric ferrous ions

International Nuclear Information System (INIS)

Karvaly, B.; Badinka, C.; Keszthelyi, L.; Erdei, L.

1975-01-01

The results of Moessbauer experiments made on liposome systems of a large specific area are presented. In the study lecithin was used as a membrane-forming material. The measurements were carried out on frozen liposome systems, at various 57 Fe/lipid concentration ratios, pH values and temperatures. Since the presence of liposomes had no noticeable influence on the Moessbauer spectra of Fe 2+ ions, only lecithin Fe 3+ systems were considered. Moessbauer spectra in case of Fe 3+ solutions with lecithin showed marked quadrupole splitting (exhibiting an anomalous temperature dependence) which is not shown in case of pure Fe 3+ solution. (Z.S.)

Moessbauer spectroscopic study of iron in Japanese cedar bark (Paper No. HF-02)

International Nuclear Information System (INIS)

Singh, T.B.; Ichikuni, M.

1990-02-01

The bark samples of Japanese cedar collected from mountainous and urban areas were characterised by Moessbauer spectroscopy. The Moessbauer spectra showed that iron in the bark samples was distributed among paramagnetic Fe 2+ , Fe 3+ and magnetic iron and their relative abundance changed appreciably from one area to other. Further, low Fe 2+ /Fe 3+ ratio and high magnetic iron in urban samples indicated an influence of human activities. (author). 1 tab., 1 fig

Thermal treatment of the Fe78 Si9 B13 alloy and the analysis of it magnetic properties through Moessbauer spectroscopy and Positronium annihilation

International Nuclear Information System (INIS)

Lopez M, A.

2005-01-01

The present work is divided in five chapters. In the first one a general vision of the amorphous alloys is given from antecedents, structure, obtaining methods, properties and problems that at the moment, focusing us in a certain moment to the iron base alloys and the anomalous problem of hardness that it presents the alloy Fe 78 Si 9 B 13 like previously mention us. The second chapter tries on the basic theory of the techniques of Moessbauer spectroscopy and Positron Annihilation spectroscopy, used for the characterization of our alloy as well as the complementary technique of X-ray diffraction (XRD) to observe that the amorphous phase was even studying. The third chapter describes the experimental conditions that were used to study the alloy Fe 78 Si 9 B 13 in each one of their thermal treatments. In the fourth chapter the obtained results and their discussion are presented. In the fifth chapter the conclusions to which were arrived after analyzing the results are presented. (Author)

Moessbauer study of Mg-Ni(Fe) alloys processed as materials for solid state hydrogen storage

Energy Technology Data Exchange (ETDEWEB)

Palade, P.; Principi, G., E-mail: giovanni.principi@unipd.it; Sartori, S.; Maddalena, A. [Universita di Padova, Settore Materiali, DIM (Italy); Lo Russo, S. [Universita di Padova, Dipartimento di Fisica (Italy); Schinteie, G.; Kuncser, V.; Filoti, G. [National Institute for Materials Physics, Solid State Magnetism Department (Romania)

2006-02-15

Mg-Ni-Fe magnesium-rich intermetallic compounds were prepared following two distinct routes. A Mg{sub 88}Ni{sub 11}Fe{sub 1} sample (A) was prepared by melt spinning Mg-Ni-Fe pellets and then by high-energy ball milling for 6 h the obtained ribbons. A (MgH{sub 2}){sub 88}Ni{sub 11}Fe{sub 1} sample (B) was obtained by high-energy ball milling for 20 h a mixture of Ni, Fe and MgH{sub 2} powders in the due proportions. A SPEX8000 shaker mill with a 10:1 ball to powder ratio was used for milling in argon atmosphere. The samples were submitted to repeated hydrogen absorption/desorption cycles in a Sievert type gas-solid reaction controller at temperatures in the range 520 - 590 K and a maximum pressure of 2.5 MPa during absorption. The samples were analysed before and after the hydrogen absorption/desorption cycles by X-ray diffraction and Moessbauer spectroscopy. The results concerning the hydrogen storage properties of the studied compounds are discussed in connection with the micro-structural characteristics found by means of the used analytical techniques. The improved kinetics of hydrogen desorption for sample A, in comparison to sample B, has been ascribed to the different behaviour of iron atoms in the two cases, as proved by Moessbauer spectroscopy. In fact, iron results homogeneously distributed in sample A, partly at the Mg{sub 2}Ni grain boundaries, with catalytic effect on the gas-solid reaction; in sample B, instead, iron is dispersed inside the hydride powder as metallic iron or superparamagnetic iron.

On the origin of discontinuity of the hyperfine fields at {sup 57}Fe nuclei in bulk iron and aerosol Fe nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Petrov, Yu.I. [Semenov Institute of Chemical Physics, Russian Academy of Sciences, Kosygin str. 4, 119991, GSP-1, Moscow (Russian Federation); Shafranovsky, E.A., E-mail: shafr@chph.ras.r [Semenov Institute of Chemical Physics, Russian Academy of Sciences, Kosygin str. 4, 119991, GSP-1, Moscow (Russian Federation); Casas, Ll. [Departament de Geologia, Universitat Autonoma de Barcelona, Edifici C, Campus de la UAB, 08193 Bellaterra (Spain); Molins, E. [Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra (Spain)

2011-03-14

Advancing the early work in which a discontinuity of hyperfine fields at {sup 57}Fe nuclei in bulk iron and in aerosol Fe nanoparticles has been revealed by analyzing their Moessbauer spectra the present Letter evidences that the existence of several peaks in the hyperfine distribution (HFD) for bulk Fe is caused with the internal magnetic fields owing to its multidomain structure whereas aerosol Fe nanoparticles are single-domain and show only a unique peak in HFD. This argument has been corroborated by transformation of the HFD pattern for Fe foil after applying the external magnetic field of 0.03 T.

Study of Moessbauer effect on LiFe5-x Alx O8, LiFe 5-x Gax O8 and LiGa5-x Fex O8 systems

International Nuclear Information System (INIS)

Barthem, V.M.T.S.

1982-01-01

The measures obtained by Moessbauer spectroscopy from LiFe 5-x Ga x O 8 and LiFe 5-x Al x O 8 systems are presented. A comparative study of the influences of dopant diamagnetic ions on magnetic structures of lithium ferrite was performed. The LiGa 5-x Fe x O 8 systems were analysed based on the existing data from LiAl 5-x Fe x O 8 systems, otaining informations about the iron ion behaviour in both matrices. (M.C.K.) [pt

NMR and Moessbauer studies of the amorphous system Fe79P/sub 21-x/B/sub x/

International Nuclear Information System (INIS)

Amamou, A.; Durand, J.

1977-05-01

Combined NMR, spin-echo and Moessbauer experiments have been performed to obtain hyperfine field distributions of the transition metal and metalloid elements in splat-cooled amorphous Fe 79 P 21 /sub -x/B/sub x/ alloys. These distributions are related to the local environments of the elements. The NMR signals are observed in the low frequency range 20-60 MHz and all the nuclei, i.e. Fe, P and B, may contribute to the spectral distribution. The resolution of the spectra into that due to Fe and (P + B) nuclei was made possible by using samples prepared with an Fe 56 isotope. The Fe distribution thus obtaned shows general agreement with the Moessbauer field distribution. From a careful analysis of the NMR data, the hyperfine field at the B nuclei in these amorphous alloys is found to range from 24 to 26 KG increasing with B content. An upper limit of 8 KG for the half-width is attributed to this distribution. The Moessbauer spectra of the Fe 57 nuclei resemble those for the crystalline Fe 75 P 25 /sub -x/B/sub x/ alloys. A fit of the spectra shows a field distribution which suggests the presence of structure. Such a structure may correspond to various Fe sites, also seen in the crystalline alloys. The distributions generally lie between about 160 and 330 KG, with a maximum at about 260 KG. These spectra do not show the presence of Fe nuclei with essentially zero hyperfine field as was obtained for amorphous Fe-Pd-P by Sharon et al. and for amorphous Fe-P by Logan et al. With increasing B content the center of gravity of the Fe distribution shifts to higher values. From a systematic study of the NMR lines and other considerations it is concluded that the P field distribution is broad and its hyperfine field is between 20 and 35 KG for the higher P concentration alloys

Microscopic studies of a SnO2/α-Fe2O3 architectural nanocomposite using Moessbauer spectroscopic and magnetic measurements

International Nuclear Information System (INIS)

Hayashi, Naoaki; Muranaka, Shigetoshi; Yamamoto, Shinpei; Takano, Mikio; Zhang Dongfeng; Sun Lingdong; Yan Chunhua

2008-01-01

A SnO 2 /α-Fe 2 O 3 architectural nanocomposite, which was evidenced as SnO 2 nanorod arrays assembled on the surface of α-Fe 2 O 3 nanotubes in our previous study, was investigated microscopically by means of Moessbauer spectroscopic and magnetic measurements. It was found for the SnO 2 nanorods that Fe 3+ ions substituted slightly to Sn 0.998 Fe 0.002 O 2 . Concerning the α-Fe 2 O 3 tubes, the Morin transition, which was completely suppressed in the mother, SnO 2 -free α-Fe 2 O 3 nanotubes, was found to be recovered locally. We speculate that it takes place in the interface area as a result of structural modification needed for the connection with the SnO 2 nanorods. - Graphic abstract: 57 Fe Moessbauer spectrum of SnO 2 /α-Fe 2 O 3 architectural nanocomposite evidenced as SnO 2 nanorod arrays assembled on the surface of α-Fe 2 O 3 nanotubes. (I: Fe-doped SnO 2 nanorods, II: α-Fe 2 O 3 nanotubes) It was found for the SnO 2 nanorods that Fe 3+ ions substituted slightly to Sn 0.998 Fe 0.002 O 2

Moessbauer spectroscopic study of rust formed on a weathering steel and a mild steel exposed for a long term in an industrial environment

International Nuclear Information System (INIS)

Kamimura, Takayuki; Nasu, Saburo; Tazaki, Takashi; Kuzushita, Kaori; Morimoto, Shotaro

2002-01-01

The rusts formed on mild steel (15-year exposure) and weathering steel (32-year exposure) exposed to an industrial environment have been characterized by means of X-ray diffraction technique and 57 Fe Moessbauer spectroscopy. By using an X-ray diffraction method, it is suggested that the rusts formed on both steels consist of the crystalline α-FeOOH, γ-FeOOH and an X-ray amorphous phase, which gives no peak to X-ray diffraction pattern. The amount of the X-ray amorphous phase exceeds 50% of the total amount of the rust. The 57 Fe Moessbauer spectra observed at 10K indicate that the rust contains only α-FeOOH, γ-FeOOH and Fe 3-δ O 4 (γ-Fe 2 O 3 ) for mild steel, and only α-FeOOH and γ-FeOOH for weathering steel. The X-ray amorphous substance in the rust payer formed on mild steel possesses the structures of mainly α-FeOOH showing superparamagnetism owing to its small particle size, and Fe 3-δ O 4 (γ-Fe 2 O 3 ). They are contained both in the inner rust layer and in the outer rust layer. The X-ray amorphous phase in the rust layer formed on weathering steel is mainly α-FeOOH. (author)

Biological mineralization of iron: Studies using Moesbauer spectroscopy and complementary techniques

International Nuclear Information System (INIS)

Webb, J.; Kim, K.S.; Tran, K.C.; Pierre, T.G.S.

1988-01-01

Biological deposition of solid Fe-containing phases can be studied using 57 Fe Moessbauer spectroscopy. Other techniques are needed in order to understand this complex process. These include proton-induced X-ray and γ-ray emission (PIXE/PIGME), electron microscopy, electron and X-ray diffraction, infrared spectroscopy and chemical characterization of organic components. This paper reviews and evaluates the application of these techniques to biological mineralization of Fe, particularly that occurring in the radula teeth of the marine molluscs, chitons and limpets. (orig.)

Fe(II-III) Hydroxysalt Green Rusts; from Corrosion to Mineralogy and Abiotic to Biotic Reactions by Moessbauer Spectroscopy

International Nuclear Information System (INIS)

Genin, J.-M. R.

2004-01-01

Fe(II)-Fe(III) hydroxysalts commonly called green rusts are layered double hydroxides of formula [Fe II (1-x) Fe III x (OH) 2 ] x+ .[(x/n)A n- .(m/n)H 2 O] x- constituted of brucite-like layers containing Fe cations in the centres of OH - octahedrons and interlayers, which anions and water molecules belong to. They play a key role in corrosion and environmental sciences as well as mineralogy since they are, on the one hand, intermediate products between Fe(II) and Fe(III) states and, on the other hand, can be the major iron-bearing mineral in hydromorphic gley soils. Their crystal structure, Moessbauer spectra, methods of synthesis, abiotic as well as biotic, and some applications are presented here.

Moessbauer spectra of white micas from the Central Western Carpathians Mountains

International Nuclear Information System (INIS)

Sitek, J; Toth, I; Sulak, M; Putis, M

2010-01-01

Potassium white micas from the rocks included into Cretaceous deformation zones (ca. 100-70 Ma in age) of the Central Western Carpathians were investigated by Moessbauer spectroscopy. White micas formed during a polystage evolution and changing P-T conditions of their crystallization in crustal-scale shear zones. We found criteria for distinguishing generations of celadonite-poor (muscovitic) and celadonite-rich (phengitic) white micas using Moessbauer spectroscopy. This method revealed contrasting spectra characterized by typical quadrupole doublets corresponding to Fe 2+ Fe 3+ contents in white micas. They are in the range of 2.9-3.0 mm/s for phengite, and 2.6-2.7 mm/s for muscovite. Moessbauer spectra reflect well the chemical changes in white mica aggregates, especially of those close to the end-member muscovite and (alumino-)celadonite compositions.

Moessbauer spectra of white micas from the Central Western Carpathians Mountains

Energy Technology Data Exchange (ETDEWEB)

Sitek, J; Toth, I [Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, Bratislava (Slovakia); Sulak, M; Putis, M, E-mail: jozef.sitek@stuba.s [Department of of Mineralogy and Petrology, Faculty of Natural Sciences, Comenius University Bratislava, Mlynska dolina G, 842 15 Bratislava (Slovakia)

2010-03-01

Potassium white micas from the rocks included into Cretaceous deformation zones (ca. 100-70 Ma in age) of the Central Western Carpathians were investigated by Moessbauer spectroscopy. White micas formed during a polystage evolution and changing P-T conditions of their crystallization in crustal-scale shear zones. We found criteria for distinguishing generations of celadonite-poor (muscovitic) and celadonite-rich (phengitic) white micas using Moessbauer spectroscopy. This method revealed contrasting spectra characterized by typical quadrupole doublets corresponding to Fe{sup 2+} Fe{sup 3+} contents in white micas. They are in the range of 2.9-3.0 mm/s for phengite, and 2.6-2.7 mm/s for muscovite. Moessbauer spectra reflect well the chemical changes in white mica aggregates, especially of those close to the end-member muscovite and (alumino-)celadonite compositions.

Rapid spin-state interconversion in the bis-complex of tris-(1-pyrazolyl) methane with Fe(II) studied by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Winkler, H.; Trautwein, A.X.; Toftlund, H.

1992-01-01

Dynamic spin equilibrium is observed in a complex of the [Fe(II)-N 6 ] type above room temperature. The Moessbauer lineshapes as function of temperature can be understood by means of the random-frequency-modulation model. Taking into accout the different Lamb-Moessbauer factors of the low- and high-spin state yields true populations of the two spin states. The transition rates follow rather well an Arrhenius law. With appropriate assumptions an activation energy ΔE LH =18(1) kJmol -1 is deduced. (orig.)

Moessbauer spectroscopic study on valence-detrapping and trapping of mixed-valence trinuclear iron (III, III, II) fluorine-substitute benzoate complexes

International Nuclear Information System (INIS)

Sakai, Y.; Onaka, S.; Ogiso, R.; Takayama, T.; Takahashi, M.; Nakamoto, T.

2012-01-01

Four mixed-valence trinuclear iron(III, III, II) fluorine-substituted benzoate complexes were synthesized; Fe 3 O(C 6 F 5 COO) 6 (C 5 H 5 N) 3 ·CH 2 Cl 2 (1), Fe 3 O(C 6 F 5 COO) 6 (C 5 H 5 N) 3 (2), Fe 3 O(2H-C 6 F 4 COO) 6 (C 5 H 5 N) 3 (3), and Fe 3 O(4H-C 6 F 4 COO) 6 (C 5 H 5 N) 3 (4). By means of 57 Fe-Moessbauer spectroscopy, valence-detrapping and trapping phenomena have been investigated for the four mixed-valence complexes. The valence state of three iron ions is trapped at lower temperatures while it is fully detrapped at higher temperatures for 1. Valence detrapping is not observed for 2, 3, and 4 even at room temperature, although Moessbauer spectra for 3 and 4 show a complicated temperature dependence. (author)

Studies of. gamma. -ray irradiation effects on tris(. beta. -diketonato)iron(III) and cobalt(III) coordination compounds by means of Moessbauer spectroscopy and magnetic susceptibility measurements

Energy Technology Data Exchange (ETDEWEB)

Sakai, Y.; Endo, K.; Sano, H. (Tokyo Metropolitan Univ. (Japan). Faculty of Science)

1981-06-01

Both absorption Moessbauer spectroscopy and magnetic susceptibility measurements on tris(..beta..-diketonato)iron(III) and cobalt(III) compounds indicate that ligands which have phenyl group as a substituent are more stable to ..gamma..-ray radiolysis, in accordance with previous results of emission Moessbauer spectroscopic studies of /sup 57/Co-labelled tris (..beta..-diketonato)cobalt(III) compounds.

Influence of preparation conditions on precipitated iron oxides and hydroxides: a Moessbauer spectroscopy study

International Nuclear Information System (INIS)

Dlamini, H.; Pollak, H.; Coville, N.J.; Van Wyk, J.A.

1999-01-01

A mixture of hematite and an amorphous Fe(III) hydroxide species are formed during the preparation of precipitated iron based catalysts. The percentage of the two phases varies with the change in the preparation conditions. Moessbauer spectroscopy reveals that maximum hematite was formed between pH 6-7 and C Fe3+ /C Na2CO3 of 0.33-0.375 corresponding to an increase in product crystallinity as determined from XRD line broadening analysis. The change in the product distribution with preparation conditions suggests the presence of two competing reactions. Particle size distribution of the hematite phase indicates that nucleation and particle growth occur at the same time. (author)

Applications of Moessbauer spectroscopy to the structural characterization of minerals and products of the country 's mining - metallurgical industry

International Nuclear Information System (INIS)

Herrera Palma, Victoria; Cruz Inclan, Carlos Manuel

2016-01-01

Since the seventies of the past century Moessbauer Spectroscopy (MS) has been systematically and successfully applied at CEADEN in the study and characterization of lateritic and other iron-rich ores, and different products of their industrial processing as well. Due to their high iron and chrome content these materials seemed to be attractive as raw material for the production of several enriched fractions in metallurgical applications. Such studies showed that the systematic application of MS combined with X- Ray Diffraction and other techniques like neutron Diffraction, Thermal and Calorimetric analysis and Optical and Electron Microscopies, has allowed a higher level of accuracy in the crystallographic characterization, and the phase composition and other specific properties assessment. As examples in this direction, in the present paper results of the study on two different iron-bearing materials are reported: a) magnetite of Mina Grande (in Santiago de Cuba), and b) Monitoring of a proposed process using concentration tables for chrome enrichment from tailings of the nickel plant 'Hector Ramos Latour' at Holguin, both areas located in the east of Cuba. It is evidenced that a right combination of 57 Fe Moessbauer Spectroscopy with other mentioned methods is nowadays the wisest and most efficient way for a thorough identification and characterization of iron-bearing mineral ores and products in mining and metallurgical industry. (Author)

Moessbauer Study of the Ball Milling Disordering Process of FeAl Intermetallic Compounds

International Nuclear Information System (INIS)

Oleszak, Dariusz; Bruna, Pere; Crespo, Daniel; Pradell, Trinitat

2005-01-01

Structural changes during ball milling of ordered Fe50Al50 intermetallic compounds were studied. X-Ray diffraction allowed the computation of a Long Range Order parameter (LRO) which dropped to zero after a short milling time. The initial B2 ordered structure gradually transforms into a disordered BCC structure, with a final crystallite size of about 25 nm. Moessbauer spectroscopy was used for obtaining a Chemical Short Range Order parameter (CSRO). Using a semiempirical n-body noncentral potential a model of the partially disordered B2 structure was built allowing computing the distribution of Quadrupole Splitting during the disordering process. Comparison between experimental and simulated Moessbauer spectra shows a maximum of disorder in the system for 5h milling, related to the highest value of the lattice spacing and the broader quadrupole hyperfine distribution. However, after milling for times longer than 5h, there is a change on the behavior of the experimental data that cannot be explained by the simple disordering process

TlCu1.73Fe0.27Se2 studied by means of Moessbauer spectroscopy and SQUID magnetometry

International Nuclear Information System (INIS)

Kamali-M, S; Ericsson, T; Haeggstroem, L; Berger, R; Ronneteg, S; Felton, S

2006-01-01

TlCu 2-x Fe x Se 2 is a p-type metal for x c is 55(5) K as found from both SQUID and Moessbauer spectra. At T c the magnetic hyperfine fields are distributed with a maximum at about 30 T, which are compared to the measured magnetic moment per iron atom, which is 0.97 μ B /Fe as found from SQUID measurements. The experimental results are compared to results using other methods on isostructural Tl selenides

Moessbauer study of corrosion induced by acid rain

International Nuclear Information System (INIS)

Arshed, M.; Hussain, N.; Siddiqui, M.; Anwar-ul-Islam, M.; Rehman, S.; Butt, N.M.

1997-01-01

Strictly speaking acid rain refers to wet precipitation of pollutants S0/sub 2/SO/sub 3/ and NO/sub x/HNO/sub 3/ which have dissolved in cloud and rain droplets to from sulphuric and nitric acids. Acid rain has seriously damaged pine and spruce forests in Canada, USA and Europe. In these areas it has caused damage to buildings, reduced fish population due to acidification of lakes and rivers, and affected health of human beings as a result of poor water quality. The corrosion products formed in a simulated acid rain environment have been identified with transmission Moessbauer spectroscopy using a /sup 57/Co source. They were found to be gamma-FeOOH, alpha-FeOOH, gamma-Fe/sub 2/O/sub 3/ and a phase with unfamiliar parameters which seems to be amorphous in nature and can be considered as an intermediate phase. (author)

Moessbauer determination of magnetic structure of Fe/sub 3/BO/sub 6/ crystal

Energy Technology Data Exchange (ETDEWEB)

Kovalenko, P.P.; Labushkin, V.G.; Ovsepyan, A.K.; Sarkisov, Eh.R.; Smirnov, E.V.; Prokopov, A.R.; Seleznev, V.N.

1984-10-01

The magnetic structure of a Fe/sub 3/BO/sub 6/ crystal belonging to space group Dsub(2h)sup(16)(Psub(nma)) is determined by the Moessbauer ..gamma..-radiation diffraction. The bragg reflection (700) of Moessbauer 14.4 keV ..gamma..-quanta from the Fe/sub 3/BO/sub 6/ monocrystal has been studied experimentally. A high sensitivity of the interference of ..gamma..-quantum diffraction scattering on Fe nuclei being in crystallographically non-equivalent 8d- and 4s-positions to the type of magnetic ordering in the crystal is used for determination of the magnetic structure. Agreement of the experimental results with the theoretical calculations, conducted for types of magnetic ordering resolved by the symmetry of the crystal, permitted to reliably determine the magnetic structure of this compound. The results obtained confirm the data of neutrondiffraction studies on magnetic ordering in Fe/sub 3/BO/sub 6/. Advantages of the Moessbauer-diffraction study, as compared to the magnetic neutrondiffraction method, in particular, for investigation of crystals, in which the hyperfine magnetic fields on Fe nuclei have different values, are revealed and discussed in detail.

Application of Moessbauer spectroscopy to iron-57 bauxite

International Nuclear Information System (INIS)

Hill, V.G.; Wynter, C.

1978-01-01

Five different samples from bauxite and related terrains in Jamaica were selected for Moessbauer analysis. Sample 1 is lithiophorite, a lithium aluminum manganese oxide, present as an impurity in Jamaican bauxite; sample 2 is a common red bauxite ore, from Kirkvine, Manchester; sample 3 is a pisolitic bauxite from Reynolds, St. Ann; sample 4 is a red bauxite with pisolites from Mocho; and sample 5 is a shaly material containing some lateritic material which characterizes mining areas. Whereas sample 1 contains fine particles of goettite and/or aluminium substituted goettite, samples 2,3,4,5 contain mixtures of haematite and goettite and/or aluminium substituted goettite in varying concentrations. The findings are consistent with Hill's bauxitization process

Study by Moessbauer spectroscopy of the iron-dextran (Imferon)

International Nuclear Information System (INIS)

Araujo, S.I. de; Danon, J.

1985-01-01

The iron-dextran complexes (imferon) are very important in the anemia treatment resulting of the iron insufficiency. Recent studies by electron diffraction denoted that the imferon is structurally different of the ferritin, one protein which constitute the iron reserve substance in the organisms. However, the obtained data in the imferon by Moessbauer spectroscopy, in different temperature ranges (room, liquid nitrogen and liquid He), show a great resemblance between this compound and the ferritin. A Fe 3+ distorted octahedrical coordenation is observed in both compounds, agreeing with measurements done in ferritin by EXAFS. In spite of the concordant results, persist, nevertheless, some discrepancies. The ferritin seems to be a rather more ionic than the imferon, possibly due to the rather higher interatomic distance in the former compound. In these measurements, a field of 484,6 + - 5 KOe is found for the imferon which, compared with the field of 493 + - 10 KOe for ferritin, confirms to be the ferritin more ionic than the imferon. It is, however, a litle difference, when it is compared to the existent between the iron binary oxides β FeOOH and γFeOOH. (L.C.) [pt

Quantitative Moessbauer analysis

International Nuclear Information System (INIS)

Collins, R.L.

1978-01-01

The quantitative analysis of Moessbauer data, as in the measurement of Fe 3+ /Fe 2+ concentration, has not been possible because of the different mean square velocities (x 2 ) of Moessbauer nuclei at chemically different sites. A method is now described which, based on Moessbauer data at several temperatures, permits the comparison of absorption areas at (x 2 )=0. (Auth.)

High pressure Moessbauer spectroscopy with nuclear resonant forward scattering of synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Nasu, Saburo [Osaka Univ., Toyonaka (Japan). Faculty of Engineering Science

1996-04-01

The first observation of the pressure-induced transition from the antiferromagnetic to the ferromagnetic SrFeO{sub 3} was succeeded by measuring Moessbauer spectroscopy under high pressure produced by the diamond anvil cell (DAC). Sample is a polycrystal powder of antiferromagnetic SrFe0{sub 3} with the Neel temperature T{sub N}=140 K, the cubic system and perovskite type crystal. The average pressures used were 44 GPa and 74 GPa (300 K). SrFeO{sub 3} is paramagnetic material at 300 K, but the Neel temperature increases more than 300 K under high pressure and the quantized axis turns to the external magnetic field, so that we take it as it means the system displaying the phase transition to the ferromagnet. By the method, we can practice the measurement at low and high temperature under the external magnetic field by using the polarized light source. (S.Y.)

In-situ phase analysis by a versatile miniaturized Moessbauer spectrometer

International Nuclear Information System (INIS)

Klingelhoefer, G.; Held, P.; Bernhardt, B.; Foh, J.; Teucher, R.; Kankeleit, E.

1998-01-01

The element iron plays a major role in modern industries and technologies as for instance car-industry, mineral processing and steel production and power plants. For quality control, process monitoring and device inspection (e.g., pipes in power plants) a fast, non-destructive and sensitive analytical method is desirable. 57 Fe Moessbauer spectroscopy is able to determine the different iron phases (e.g., oxides, sulfides, nitrates, carbonates and carbides) and therefore would be the ideal tool to perform this job. We have developed a miniaturized backscattering Moessbauer spectrometer for space applications which will be modified and used for industrial applications under certain circumstances. The instrument is designed in a modular way which would allow to adapt it to different applications. The instrument has approximately the size of a soft drink can, a weight of about 0.5 kg, and a power consumption of about 3 watts

Moessbauer study of cobalt and iron in the cyanobacterium (blue green alga)

International Nuclear Information System (INIS)

Ambe, Shizuko

1990-01-01

Moessbauer emission and absorption studies have been performed on cobalt and iron in the cyanobacterium (blue-green alga). The Moessbauer spectrum of the cyanobacterium cultivated with 57 Co is decomposed into two doublets. The parameters of the major doublet are in good agreement with those of cyanocobalamin (vitamin B 12 ) labeled with 57 Co. The other minor doublet has parameters close to those of Fe(II) coordinated with six nitrogen atoms. These suggest that cobalt is used for the biosynthesis of vitamin B 12 or its analogs in the cyanobacterium. The spectra of the cyanobacterium grown with 57 Fe show that iron is in the high-spin trivalent state and possibly in the form of ferritin, iron storage protein. (orig.)

Study on Moessbauer spectra of hemoglobin in thalassemia

International Nuclear Information System (INIS)

Guo Xuanhui; Zhao Nanming; Zhang Xiufang

1988-01-01

The 57 Fe Moessbauer spectra of erythrocytes in normal subjects and nine patients of different thalassemias were studied. Together with clinical analysis, the correlation between the components in the spectra and different types of anemias was discussed. (orig.)

Magnetic and Moessbauer studies of amorphous Fe72-xYxHo8B20 alloys

International Nuclear Information System (INIS)

Krishnan, R.; Dumond, Y.; Ajan, A.; Shringi, S.N.; Prasad, S.

1996-01-01

We have carried out magnetic and Moessbauer studies of amorphous Fe 72-x Y x Ho 8 B 20 alloys. The Fe moment decreases with the addition of Y and a magnetic compensation occurs at 4 K for x=16. The temperature and field dependences of the magnetization have been interpreted using the mean field theory and Chudnovsky's model, respectively. These analyses yield some interesting parameters such as the random anisotropy, the exchange interactions J Fe-Fe , J Fe-Ho , etc. The Moessbauer studies show that the average hyperfine field decreases linearly with the addition of Y, in accordance with the decrease in the Fe moment. (orig.)

57Fe Moessbauer spectroscopic study on surface products of thin iron plates exposed to ambient atmosphere as a means of environmental monitoring

International Nuclear Information System (INIS)

Matsuo, Motoyuki; Kobayashi, Takaaki

1993-01-01

Conversion electron and transmission Moessbauer spectroscopy were applied to the analysis of thin iron plates exposed to the ambient atmosphere. The degree of corrosion of the iron plates was classified into three categories according to the kind and thickness of rust evaluated by Moessbauer spectra. The severe corrosion took place in seaside and roadside areas. The medium corrosion was observed in urban areas, and the weak corrosion occurred in suburban and mountainous areas. This fact implies that the surface products of iron plates can successfully reflect the ambient atmosphere to which the plates were exposed. (orig.)

Moessbauer spectroscopy of He irradiated austenitic stainless steel SUS304 at low temperature

Energy Technology Data Exchange (ETDEWEB)

Horii, Kiyomasa; Ishibashi, Tetsu; Toriyama, Tamotsu; Wakabayashi, Hidehiko; Iijima, Hiroshi [Musashi Inst. of Tech., Tokyo (Japan); Kawasaki, Katsunori; Hayashi, Nobuyuki; Sakamoto, Isao

1996-04-01

SUS 304 austenitic stainless steel causes the magnetic transition at 60 K, and the Young`s modulus lowers. In addition, its composition elements have the large (n,{alpha}) reaction cross section to high energy neutrons, and helium is apt to be generated, and this is a factor that lowers the material strength. In the He-irradiated parts in austenitic stainless steel, the precursory state of martensite transformation should exist, and its effect is considered to be observable by carrying out low temperature Moessbauer spectroscopy. As to the preparation of He-irradiation samples, the SUS 304 foils used and the irradiation conditions are described. The measurement of low temperature Moessbauer spectra for the samples without irradiation and with irradiation is reported. In order to determine the magnetic transition point, the thermal scanning measurement was carried out for the samples without or with irradiation. The martensite transformation was measured by X-ray diffraction and transmission type Moessbauer spectroscopy. In order to observe the state of the sample surfaces, the measurement by internal conversion electron Moessbauer spectroscopy was performed. These results and the temperature dependence of the Moessbauer spectra for the irradiated parts are reported. (K.I.)

Moessbauer spectroscopy of He irradiated austenitic stainless steel SUS304 at low temperature

International Nuclear Information System (INIS)

Horii, Kiyomasa; Ishibashi, Tetsu; Toriyama, Tamotsu; Wakabayashi, Hidehiko; Iijima, Hiroshi; Kawasaki, Katsunori; Hayashi, Nobuyuki; Sakamoto, Isao.

1996-01-01

SUS 304 austenitic stainless steel causes the magnetic transition at 60 K, and the Young's modulus lowers. In addition, its composition elements have the large (n,α) reaction cross section to high energy neutrons, and helium is apt to be generated, and this is a factor that lowers the material strength. In the He-irradiated parts in austenitic stainless steel, the precursory state of martensite transformation should exist, and its effect is considered to be observable by carrying out low temperature Moessbauer spectroscopy. As to the preparation of He-irradiation samples, the SUS 304 foils used and the irradiation conditions are described. The measurement of low temperature Moessbauer spectra for the samples without irradiation and with irradiation is reported. In order to determine the magnetic transition point, the thermal scanning measurement was carried out for the samples without or with irradiation. The martensite transformation was measured by X-ray diffraction and transmission type Moessbauer spectroscopy. In order to observe the state of the sample surfaces, the measurement by internal conversion electron Moessbauer spectroscopy was performed. These results and the temperature dependence of the Moessbauer spectra for the irradiated parts are reported. (K.I.)

Study of the EPR and Moessbauer spectra of iron phosphites

International Nuclear Information System (INIS)

Ebert, M.; Kavan, L.

1978-01-01

The EPR and Moessbauer spectra of polycrystalline samples of ferrous phosphites FeHPO 3 .3H 2 O, FeH 2 P 2 O 5 , FeH 4 P 2 O 6 .1/2H 2 O, FeH 10 P 4 O 12 .4H 2 O and ferric phosphites Fe 2 (HPO 3 ) 3 .9h 2 O, FeH 3 P 2 O 6 .3H 2 O and Fe 4 H 33 P 15 O 45 .6H 2 O were studied. The hydrogen bonds present in hydrogen phosphite anions (polyorthophosphites) produce a decrease in the electron density on the oxygen atom in the anion and thus also a decrease in the crystal field strength with an increasing P/Fe ratio. These changes are reflected not only in the Dq values but also in the g-factors, Moessbauer isomeric shifts and quadropole splitting values. The Moessbauer spectra were measured at laboratory temperature with a Co-57/Pd source (the time for measuring one sample was about 24 hrs) and evaluated on a Hewlett-Packard computer. The EPR spectra of the polycristalline samples were measured at laboratory temperature in the 3 cm region. (T.I.)

Moessbauer and calorimetric studies of portland cement hydration in the presence of black gram pulse

International Nuclear Information System (INIS)

Rai, Sarita; Kurian, Sajith; Dwivedi, V. N.; Das, S. S.; Singh, N. B.; Gajbhiye, N. S.

2009-01-01

Effect of different concentrations of naturally occurring admixture in the form of fine powder of black gram pulse (BGP) on the hydration of Portland cement was studied by isothermal calorimetry and 57 Fe Moessbauer spectroscopy. The spectra were recorded for anhydrous cement and the hydration products at room temperature and 77 K. In the presence of BGP, the spectra showed superparamagnetic doublets at room temperature and the sextet at 77 K, due to the presence of fine particles of iron containing component. Moessbauer studies of hydration products confirmed the formation of nanosize hydration products containing Fe 3+ . The isomer shift (δ) and the quadrupole splitting (ΔE Q ) values of C 4 AF in the cement confirmed iron in an octahedral and tetrahedral environment with +3 oxidation state. The high value of quadrupole splitting showed the high asymmetry of the electron environment around the iron atom. The overall mechanism of the hydration of cement in presence of BGP is discussed.

Moessbauer characterization of the iron species from the radioactive waste processing products

Energy Technology Data Exchange (ETDEWEB)

Filoti, G; Spanu, V; Kunscer, V; Turcanu, C N [Institute of Atomic Physics, Bucharest (Romania)

1997-02-01

As part of the programme carried out in Romania in connection with the management of non-fuel cycle radioactive wastes, an experimental study has been performed on the low aqueous waste (LLAW) processing products using mainly an ``in situ`` {sup 57}Fe Moessbauer spectroscopy characterization method. The study was focused on the LLAW treatment products obtained by chemical precipitation and on the conditioning of the products obtained by cementation. Starting from a series of Moessbauer spectra obtained on precipitates prepared in various experimental condition it was shown that th composition and structure of the final products strongly depend on the process parameters i.e. reagent composition and their concentration, the order and rate of the chemical addition, the ageing time, the presence of the coagulation promoters, etc. Sometimes important effects were evidenced even at minor changes of the process parameters. The Moessbauer and other structural measurements on the cemented matrices resulted from the above mentioned precipitates or from other simulated LLAW concentrates have been also performed. (author). 11 refs, 3 figs, 7 tabs.

Moessbauer characterization of the iron species from the radioactive waste processing products

International Nuclear Information System (INIS)

Filoti, G.; Spanu, V.; Kunscer, V.; Turcanu, C.N.

1997-01-01

As part of the programme carried out in Romania in connection with the management of non-fuel cycle radioactive wastes, an experimental study has been performed on the low aqueous waste (LLAW) processing products using mainly an ''in situ'' 57 Fe Moessbauer spectroscopy characterization method. The study was focused on the LLAW treatment products obtained by chemical precipitation and on the conditioning of the products obtained by cementation. Starting from a series of Moessbauer spectra obtained on precipitates prepared in various experimental condition it was shown that th composition and structure of the final products strongly depend on the process parameters i.e. reagent composition and their concentration, the order and rate of the chemical addition, the ageing time, the presence of the coagulation promoters, etc. Sometimes important effects were evidenced even at minor changes of the process parameters. The Moessbauer and other structural measurements on the cemented matrices resulted from the above mentioned precipitates or from other simulated LLAW concentrates have been also performed. (author). 11 refs, 3 figs, 7 tabs

Moessbauer spectrometry study and metallography of paramagnetic phases from zirconium-iron system

International Nuclear Information System (INIS)

Freitas Brandao Bittencourt, C. de.

1976-01-01

Binary alloys of zirconium with 3 to 23% of iron by weight, were made by diffusion at 875 0 C of iron onto thin plates of zirconium. Moessbauer spectroscopy and optic metallography indicated the phases Zr 2 Fe and Zr 4 Fe, the bulk of which probably formed during the diffusion. These phases were confirmed by electron probe microanalysis. Moessbauer spectra showed quadrupole doublets with the same hyperfine interaction parameters in both phases, but with clearly distinct asymmetries. (author)

Moessbauer and magnetic investigation of Fe-Mn alloy

International Nuclear Information System (INIS)

Yousif, A.A.

1994-01-01

Moessbauer, X-ray, magnetization and susceptibility measurements were performed to study Fe 100-x Mn x , x = 5, 15, 39, 50. The different phases of Fe-Mn were identified, and hyperfine interaction parameters and average magnetic moments of some samples were determined. The average hyperfine field and average magnetic moment decrease as x increases. The influence of the Mn neighbourhood on the derived parameters is discussed in the light of calculations using the first principle discrete variational method in the local density approximation. (orig.)

Influence of mechanical activation on the Moessbauer spectra of the sulfides

International Nuclear Information System (INIS)

Lipka, J.; Miglierini, M.; Sitek, J.; Balaz, P.; Tkacova, K.

1993-01-01

Moessbauer spectroscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, electron paramagnetic resonance and X-ray diffraction were used to identify changes of surface, structure and spectroscopic properties of sulfide minerals produced by mechanical activation. In the present study we report the results of chalcopyrite (CuFeS 2 ), pyrite (FeS 2 ), cinnabar (HgS), bornite (Cu 5 FeS 4 ) and zinc sulfide (ZnS). The influence of energy input to the mill and the nature of grinding environment have been investigated upon the Fe contamination of the materials. (orig.)

Influence of mechanical activation on the Moessbauer spectra of the sulfides

Energy Technology Data Exchange (ETDEWEB)

Lipka, J.; Miglierini, M.; Sitek, J. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava, Slovak Republic (Czechoslovakia)); Balaz, P.; Tkacova, K. (Mining Inst. of the Slovak Academy of Sciences, Kosice, Slovak Republic (Czechoslovakia))

1993-04-01

Moessbauer spectroscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, electron paramagnetic resonance and X-ray diffraction were used to identify changes of surface, structure and spectroscopic properties of sulfide minerals produced by mechanical activation. In the present study we report the results of chalcopyrite (CuFeS[sub 2]), pyrite (FeS[sub 2]), cinnabar (HgS), bornite (Cu[sub 5]FeS[sub 4]) and zinc sulfide (ZnS). The influence of energy input to the mill and the nature of grinding environment have been investigated upon the Fe contamination of the materials. (orig.).

{sup 57}Fe emission Mössbauer spectroscopy following dilute implantation of {sup 57}Mn into In {sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Mokhles Gerami, A.; Johnston, K.; Gunnlaugsson, H. P., E-mail: Haraldur.p.gunnlaugsson@cern.ch [PH Div, CERN (Switzerland); Nomura, K. [Tokyo University of Science, Photocatalysis International Research Center (Japan); Mantovan, R. [IMM-CNR, Laboratorio MDM (Italy); Masenda, H. [University of the Witwatersrand, School of Physics (South Africa); Matveyev, Y. A. [Moscow Institute of Physics and Technology (Russian Federation); Mølholt, T. E. [PH Div, CERN (Switzerland); Ncube, M. [University of the Witwatersrand, School of Physics (South Africa); Shayestehaminzadeh, S. [University of Iceland, Science Institute (Iceland); Unzueta, I. [Euskal Herriko Unibertsitatea (UPV/EHU), BCMaterials & Elektrizitate eta Elektronika Saila (Spain); Gislason, H. P. [University of Iceland, Science Institute (Iceland); Krastev, P. B. [Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy (Bulgaria); Langouche, G. [Instituut voor Kern-en Stralings Fysika, KU Leuven (Belgium); Naidoo, D. [University of the Witwatersrand, School of Physics (South Africa); Ólafsson, S. [University of Iceland, Science Institute (Iceland); Collaboration: the ISOLDE collaboration

2016-12-15

Emission Mössbauer spectroscopy has been utilised to characterize dilute {sup 57}Fe impurities in In {sub 2}O{sub 3} following implantation of {sup 57}Mn (T{sub 1/2} = 1.5 min.) at the ISOLDE facility at CERN. From stoichiometry considerations, one would expect Fe to adopt the valence state 3 + , substituting In {sup 3+}, however the spectra are dominated by spectral lines due to paramagnetic Fe{sup 2+}. Using first principle calculations in the framework of density functional theory (DFT), the density of states of dilute Fe and the hyperfine parameters have been determined. The hybridization between the 3d-band of Fe and the 2p band of oxygen induces a spin-polarized hole on the O site close to the Fe site, which is found to be the cause of the Fe{sup 2+} state in In {sub 2}O{sub 3}. Comparison of experimental data to calculated hyperfine parameters suggests that Fe predominantly enters the 8b site rather than the 24d site of the cation site in the Bixbyite structure of In {sub 2}O{sub 3}. A gradual transition from an amorphous to a crystalline state is observed with increasing implantation/annealing temperature.

Moessbauer and positron annihilation studies of microstructural peculiarities of iron-dextran complexes

International Nuclear Information System (INIS)

Oshtrakh, M.I.; Kopelyan, E.A.; Semionkin, V.A.; Livshits, A.B.; Kozlov, A.A.

1995-01-01

The microstructural peculiarities of pharmaceutically important iron-dextran complexes were studied by Moessbauer and positron annihilation techniques. The results of Moessbauer spectroscopy showed variations of the iron cores in iron-dextran complexes containing different forms of FeOOH and different electronic and magnetic states of iron. The results of angular correlations of annihilation radiation and positron life-time spectroscopies showed microstructural variations of the dextran shell of the iron-dextran complexes. (author) 19 refs.; 4 tabs

Influence of ruthenium ions on the precipitation of α-FeOOH, α-Fe2O3 and Fe3O4 in highly alkaline media

International Nuclear Information System (INIS)

Krehula, Stjepko; Music, Svetozar

2006-01-01

The influence of ruthenium ions on the precipitation of goethite (α-FeOOH), α-Fe 2 O 3 and Fe 3 O 4 in highly alkaline media was investigated by 57 Fe Moessbauer and FT-IR spectroscopies, thermal field emission scanning electron microscope (FE SEM) and EDS. The presence of Ru-dopant strongly affected the precipitation of α-FeOOH at highly alkaline pH, i.e. the formation of α-Fe 2 O 3 was also noticed. A decrease of hyperfine magnetic field (HMF) at RT from 35.1 T (undoped α-FeOOH) to 31.3 T for sample with [Ru]/([Ru] + [Fe]) = 0.0196 was assigned to the incorporation of ruthenium ions into the α-FeOOH structure. Moessbauer spectroscopy showed the formation of stoichiometric Fe 3 O 4 for [Ru]/([Ru] + [Fe]) = 0.0291-0.0909. α-Fe 2 O 3 and Fe 3 O 4 did not show a tendency to the formation of solid solutions with ruthenium ions. FE SEM observations of the samples showed that reference α-FeOOH sample contained acicular particles of good uniformity, which increased the length up to ∼5 times with increase of concentration of ruthenium ions. On the other hand, large octahedral Fe 3 O 4 crystals (particles) were associated with small particles of ruthenium (hydrous) oxide with a size in the range ∼100 nm or less. A possible catalytic action of ruthenium that created reduction conditions for Fe 3+ ions and formation of Fe 2+ ions for precipitation of Fe 3 O 4 was discussed

Moessbauer spectroscopy of minerals. Pt. 3. Octahedral-site Fe2+ quadrupole splitting distributions in the phlogopite-annite series

International Nuclear Information System (INIS)

Rancourt, D.G.

1994-01-01

We develop the methodology of quadrupole splitting distribution (QSD) analysis by evaluating the influences of absorber thickness, absorber texture, and the asumed Lorentzian width on the extracted QSD. We then present the first study to describe the Moessbauer spectra of members of a mineral family in terms of QSDs. The Fe 2+ QSD and its characteristics (average QS, peak QS, skewness, and standard deviation) show gradual trends with changing Fe/(Fe+Mg) in a synthetic Al-deficient phlogopite-annite series. Al-deficient natural samples of phlogopite and annite show similar behaviour. The Fe 2+ QSDs can be interpreted as population distribuitions of local distortion environments (LDEs) and, as such, contain much information that will become more accessible as theoretical calculations linking particular LDEs to corresponding QS values are developed. (orig.)

Moessbauer spectroscopy of the Soledade meteorite

International Nuclear Information System (INIS)

Paduani, Clederson; Peres, Carlos Ariel Samudio

2004-01-01

Full text: Since the early studies of the microstructure and chemical composition of meteorites the formation of magnetic phases have attracted the attention of metallurgists. Mostly metallic specimens presented high contents of nickel and iron as major constituents, and thus the Fe-Ni alloys formed under such special conditions have been the subject of several investigations with a variety of experimental techniques. This is not an easy task considering the weathering process and the distribution of oxides in the metallic matrix, which in some cases varies in composition from one region to another. In this work we applied the Moessbauer spectroscopy to study the iron-bearing phases detected in the meteorite called Soledade. Although no one knows precisely who and when this specimen was found, it received the name of the locality from where it proceeded near the city of Passo Fundo in the state of Rio Grande do Sul in Brazil. The first studies indicate that this metallic meteorite is an octahedrite, with polycrystalline troilite, cohenite, schreibersite and rhabdites as major constituents. It consists of a solid block weighing 68 kg, with an irregular form measuring about 36x22x16 cm. (author)

Studies of iron in deep-sea sediments by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Drodt, M.; Lougear, A.; Trautwein, A.X.; Koenig, I.; Suess, E.; Koch, C. Bender

1998-01-01

The distribution of the forms of Fe in the solid phases in core samples of sediments from the Peru Basin has been investigated by Moessbauer spectroscopy with special attention to the cause of the sharp color transition between an upper green colored and a lower tan colored part. An important part of sample handling includes strict exclusion of oxygen during preparation of absorbers and measurements at cryogenic temperatures. The measurement strategy includes measurements between 77 K and 300 mK in zero external magnetic field, supplemented by measurements in external magnetic fields at 4.2 and 300 mK (up to 6.2 and 1 T, respectively). The temperature scans allow detection, identification and quantification of superparamagnetic iron oxides (goethite and hematite). The oxides are only present in samples from the upper tan-colored part of the core. The major part of the Fe(II) and Fe(III) (>80%) is present in a magnetic structure similar to that of layer silicates. The relative Fe(II) content of the layer silicates is practically identical to that determined from the paramagnetic components measured at liquid nitrogen temperature. This shows that the color transition in the sediment coincides with a change in the relative Fe(II) content in layer silicates from 11 to 37%. The color change can thus be explained by an increase in occurrence of Fe(II)-Fe(III) pairs exhibiting absorption bands due to intervalence electron transfer

[sup 57]Fe Moessbauer spectroscopic studies of the ferrocene molecular reorientation in AlPO[sub 4]-5 and AlPO[sub 4]-8 frameworks

Energy Technology Data Exchange (ETDEWEB)

Lund, A.; Nicholson, D.G. (Department of Chemistry, University of Trondheim, Dragvoll (Norway)); Parish, R.V.; Wright, J.P. (Department of Chemistry, UMIST, Manchester (United Kingdom))

1994-01-01

[sup 57]Fe Moessbauer spectroscopic studies were carried out on ferrocene guest molecules in some microporous aluminium phosphate host lattices in order to investigate their behaviour in the aluminium phosphate channels. The 300 K spectra show broad single lines with isomer shifts of 0.39 and 0.41 mm s[sup -1] relative to iron for AlPO[sub 4]-5:ferrocene and AlPO[sub 4]-8:ferrocene inclusion compounds, respectively. The absence of quadrupole splittings for these materials contrasts with the large quadrupole splitting observed for ferrocene itself at the same temperature. The low-temperature spectrum (20 K) for AlPO[sub 4]-5:ferrocene shows a doublet with quadrupole splitting of 2.37 mm s[sup -1] and an isomer shift of 0.55 mm s[sup -1]. The collapse of the quadrupole splitting at room temperature is consistent with the ferrocene molecules rotating within the channels. (au).

The effect of temperature on the crystallization of α-Fe2O3 particles from dense β-FeOOH suspensions

International Nuclear Information System (INIS)

Zic, Mark; Ristic, Mira; Music, Svetozar

2010-01-01

The effect of temperature on the crystallization of α-Fe 2 O 3 particles from dense β-FeOOH suspensions was monitored by 57 Fe Moessbauer spectroscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and energy dispersive spectroscopy. Dense suspensions of very long laterally arranged β-FeOOH fibrils were obtained at 90 deg. C. Crystallization at 120 deg. C between 18 and 72 h yielded monodisperse α-Fe 2 O 3 particles of a shape close to that of double spheres with ring. The double spheres with ring showed two narrow particle size distributions. In these particles a substructure was detected, i.e., the spheres consisted of the linear chains of interconnected α-Fe 2 O 3 subparticles. With further rise in the crystallization temperature the increase in α-Fe 2 O 3 particles and porosity became pronounced. Obviously, the aggregation mechanism played an important role in the formation of α-Fe 2 O 3 particles.

57Fe quadrupole splitting and isomer shift in various oxyhemoglobins: study using Mössbauer spectroscopy

International Nuclear Information System (INIS)

Oshtrakh, M. I.; Berkovsky, A. L.; Kumar, A.; Kundu, S.; Vinogradov, A. V.; Konstantinova, T. S.; Semionkin, V. A.

2010-01-01

A comparative study of normal human, rabbit and pig oxyhemoglobins and oxyhemoglobin from patients with chronic myeloleukemia and multiple myeloma using Mössbauer spectroscopy with a high velocity resolution demonstrated small variations of the 57 Fe quadrupole splitting and isomer shift. These variations may be a result of small structural differences in the heme iron stereochemistry of various hemoglobins.

Moessbauer study of the amorphous Pd70Fe10Si20 alloy upon transition to the crystalline state

International Nuclear Information System (INIS)

Sitek, J.; Prejsa, M.; Cirak, J.; Hucl, M.; Lipka, J.

1978-01-01

Foils of the amorphous alloy Pd 70 Fe 10 Si 20 were investigated after isothermal heating at the temperature range 350-450 0 C with a heating period from 15 min to 4 h. At 350 0 C no changes were observed in the shape of the Moessbauer spectra. At 400 0 C and at 450 0 C up to 30 min only the parameters of Moessbauer spectra consisting of two quadrupole doublets corresponding to palladium and silicon vicinities of iron atoms were changed. After further heating at 450 0 C crystalline phases of Pd 3 Fe and Fe 3 Si appeared on the Moessbauer spectra. (Auth.)

Co{sup 2 + } interaction with Azospirillum brasilense Sp7 cells: a {sup 57}Co emission Moessbauer spectroscopic study

Energy Technology Data Exchange (ETDEWEB)

Kamnev, Alexander A.; Tugarova, Anna V. [Russian Academy of Sciences, Institute of Biochemistry and Physiology of Plants and Microorganisms (Russian Federation); Biro, Borbala [Hungarian Academy of Sciences, Research Institute for Soil Science and Agricultural Chemistry (Hungary); Kovacs, Krisztina, E-mail: kkriszti@chem.elte.hu; Homonnay, Zoltan; Kuzmann, Erno; Vertes, Attila [Eoetvoes Lorand University, Institute of Chemistry (Hungary)

2012-03-15

Preliminary {sup 57}Co emission Moessbauer spectroscopic data were obtained for the soil bacterium Azospirillum brasilense Sp7 (T = 80 K) in frozen {sup 57}Co{sup 2 + }-containing suspensions and in their dried residues. The Moessbauer parameters were compared with those for A. brasilense strain Sp245 differing from strain Sp7 by ecological behaviour. Live cells of both strains showed metabolic transformations of {sup 57}Co{sup 2 + } within an hour. Differences in the parameters observed for the two strains under similar conditions suggest dissimilarities in their metabolic response to Co{sup 2 + }.

A study of human liver ferritin and chicken liver and spleen using Moessbauer spectroscopy with high velocity resolution

Energy Technology Data Exchange (ETDEWEB)

Oshtrakh, M. I., E-mail: oshtrakh@mail.utnet.ru [Ural State Technical University-UPI, Faculty of Physical Techniques and Devices for Quality Control (Russian Federation); Milder, O. B.; Semionkin, V. A. [Ural State Technical University-UPI, Faculty of Experimental Physics (Russian Federation)

2008-01-15

Lyophilized samples of human liver ferritin and chicken liver and spleen were measured at room temperature using Moessbauer spectroscopy with high velocity resolution. An increase in the velocity resolution of Moessbauer spectroscopy permitted us to increase accuracy and decrease experimental error in determining the hyperfine parameters of human liver ferritin and chicken liver and spleen. Moessbauer spectroscopy with high velocity resolution may be very useful for revealing small differences in hyperfine parameters during biomedical research.

Application of the Moessbauer spectroscopy to the investigation of the proton irradiation effects in several iron compounds

International Nuclear Information System (INIS)

Kopcewicz, M.; Kotlicki, A.

1975-01-01

The results of a study into the influence of proton irradiation on the Moessbauer effect in FeSO 4 x 7H 2 O, K 4 [Fe(CN) 6 ] x 3H 2 O and K 3 [Fe(CN) 6 ] are reported. In the interpretation of the effect observed, the 'spike' model was applied. Chemical decomposition processes due to proton irradiation and formation of the superparamagnetic state of metallic iron were investigated. A Moessbauer observation of interstitial Fe 2+ ions in irradiated FeSO 4 x 7H 2 O was made. (Z.S.)

Corrosion study of heat exchanger tubes in pressurized water cooled nuclear reactors by conversion electron Moessbauer spectroscopy

International Nuclear Information System (INIS)

Homonnay, Z.; Kuzmann, E.; Varga, K.; Nemeth, Z.; Szabo, A.; Rado, K.; Schunk, J.; Tilky, P.; Patek, G.

2005-01-01

Nuclear energy production tends to return into the focus of interest because of the constantly increasing energy need of the world and the green house effect problems of the strongest competitor oil or gas based power plants. In addition to the construction of new nuclear power plants, lifetime extension of the existing ones is the most cost effective investment in the energy business. However, feasibility and safety issues become very important at this point, and corrosion of the construction materials should be carefully investigated before decision on a potential lifetime extension of a reactor. 57 Fe-Conversion Electron Moessbauer Spectroscopy (CEMS) is a sensitive tool to analyze the phase composition of corrosion products on the surface of stainless steel. The upper ∼300 nm can be investigated due to the penetration range of conversion electrons. The corrosion state of heat exchanger tubes from the four reactor units of the Paks Nuclear Power Plant, Hungary, were analyzed by several methods including CEMS. The primary circuit side of the tubes was studied on selected samples cut out from the heat exchangers during regular maintenance. Cr- and Ni-substituted magnetite, sometimes hematite, amorphous Fe-oxides/oxyhydroxides as well as the signal of bulk austenitic steel of the tubes were detected. The level of Cr- and Ni-substitution in the magnetite phase could be estimated from the Moessbauer spectra. Correlation between earlier decontamination cycles and the corrosion state of the heat exchangers was sought. In combination with other methods, a hybrid structure of the surface oxide layer of several microns was established. It is suggested that previous AP-CITROX decontamination cycles can be responsible for this structure which makes the oxide layer mobile. This mobility may be responsible for unwanted corrosion product transport into the reactor vessel by the primary coolant.

57Fe NGR studies on three-stage hydroliquefaction of coals

International Nuclear Information System (INIS)

Jamond, M.; Bacaud, R.; Bussiere, P.; Charcosset, H.; Nickel-Pepin-Donat, B.

1990-01-01

Iron Moessbauer spectroscopy has been performed on liquefaction residues of two different French coals. In a three-stage liquefaction of high volatile bituminous coal (Freyming), without an added catalyst, the coal pyrite is not entirely converted into pyrrhotites, whereas in the presence of an added catalyst, coal pyrite is totally transformed into more dispersed pyrrhotites than those from the sample without an added catalyst; furthermore, the whole added catalyst precursor is reduced into pyrrhotites. In the case of liquefaction of subbituminous coal (Gardanne), full conversion of coal pyrite into pyrrhotites (even without an added catalyst) occurs. In addition, in the presence of the added catalyst, besides pyrrhotites, FeS is evidenced. When molybdenum-iron oxide is added as a catalyst precursor, no mixed Fe-Mo phase is detected. (orig.)

Moessbauer spectroscopy and transition metal chemistry. Fundamentals and applications

International Nuclear Information System (INIS)

Guetlich, Philipp; Trautwein, Alfred X.

2011-01-01

Moessbauer spectroscopy is a profound analytical method which has nevertheless continued to develop. The authors now present a state-of-the art book which consists of two parts. The first part details the fundamentals of Moessbauer spectroscopy and is based on a book published in 1978 in the Springer series 'Inorganic Chemistry Concepts' by P. Guetlich, R. Link and A.X. Trautwein. The second part covers useful practical aspects of measurements, and the application of the techniques to many problems of materials characterization. The update includes the use of synchroton radiation and many instructive and illustrative examples in fields such as solid state chemistry, biology and physics, materials and the geosciences, as well as industrial applications. Special chapters on magnetic relaxation phenomena (S. Morup) and computation of hyperfine interaction parameters (F. Neese) are also included. An attached CD-ROM with more than 400 full-color PowerPoint images provides self-explanatory examples. The book concentrates on teaching the technique using theory as much as needed and as little as possible. The reader will learn the fundamentals of the technique and how to apply it to many problems of materials characterization. Transition metal chemistry, studied on the basis of the most widely used Moessbauer isotopes, is in the foreground. (orig.)

Current opinion about maximum entropy methods in Moessbauer spectroscopy

International Nuclear Information System (INIS)

Szymanski, K

2009-01-01

Current opinion about Maximum Entropy Methods in Moessbauer Spectroscopy is presented. The most important advantage offered by the method is the correct data processing under circumstances of incomplete information. Disadvantage is the sophisticated algorithm and its application to the specific problems.

Spin dynamics study of magnetic molecular clusters by means of Moessbauer spectroscopy

International Nuclear Information System (INIS)

Cianchi, L.; Del Giallo, F.; Spina, G.; Reiff, W.; Caneschi, A.

2002-01-01

Spin dynamics of the two magnetic molecular clusters Fe4 and Fe8, with four and eight Fe(III) ions, respectively, was studied by means of Moessbauer spectroscopy. The transition probabilities W's between the spin states of the ground multiplet were obtained from the fitting of the spectra. For the Fe4 cluster we found that, in the range from 1.38 to 77 K, the trend of W's versus the temperature corresponds to an Orbach's process involving an excited state with energy of about 160 K. For the Fe8, which, due to the presence of a low-energy excited state, could not be studied at temperatures greater than 20 K, the trend of W's in the range from 4 to 18 K seems to correspond to a direct process. The correlation functions of the magnetization were then calculated in terms of the W's. They have an exponential trend for the Fe4 cluster, while a small oscillating component is also present for the Fe8 cluster. For the first of the clusters, τ vs T (τ is the decay time of the magnetization) has a trend which, at low temperatures (T 15 K, τ follows the trend of W -1 . For the Fe8, τ follows an Arrhenius law, but with a prefactor which is smaller than the one obtained susceptibility measurements

Hyperfine magnetic fields at 57Fe and 119Sn nuclei in the Fe48Rh52 alloy under pressure

International Nuclear Information System (INIS)

Nikolaev, I.N.; Potapov, V.N.; Bezotosnyj, I.Yu.; Mar'in, V.P.

1978-01-01

The pressure dependences of the hyperfine magnetic fields, H, and isomer shifts epsilon at the 57 Fe and 119 Sn nuclei in the Fe 48 Rh 52 alloy with an admixture of approximately 1 at. % Sn are measured by the Moessbauer effect technique. Under pressure epsilon decreases this signifying an increase (for 57 Fe) or decrease (for 119 Sn) of the s-electron density at the nuclei. In the ferromagnetic (FM) state at 398 K, ΔH/HΔp=(-2.8+-0.2)x10 -3 kbar -1 for 57 Fe and ΔH/HΔp=(-4.8+-0.8)x10 -3 kbar -1 for 119 Sn. In the antiferromagnetic (AFM) state at 78 K, ΔH/HΔp approximately 0 for 57 Fe and ΔH/HΔp=(-6.2+-1.0)x10 -3 kbar -1 for 119 Sn. The results for 57 Fe in the FM state can be ascribed to the strong dependence of the alloy matrix magnetization on the pressure and in the AFM state to the absence of local polarization of s-similar collectivized electrons and to the independence of the magnetic moments of the Fe ions of pressure. The causes of the different effect of pressure on the magnetic moments of Fe ions in the FM and AFM states are discussed. The results for 119 Sn in the FM and AFM states of the alloy are in agreement with the model of hyperfine fields at impurity Sn atoms in the magnetic matrices proposed earlier. The radial dependence of the hyperfine field at the 119 Sn nuclei in the AFM state is estimated and it is found that H(r) is stronger than r -9

The Application of Moessbauer Emission Spectroscopy to Industrial Cobalt Based Fischer-Tropsch Catalysts

International Nuclear Information System (INIS)

Loosdrecht, J. van de; Berge, P. J. van; Craje, M. W. J.; Kraan, A. M. van der

2002-01-01

The application of Moessbauer emission spectroscopy to study cobalt based Fischer-Tropsch catalysts for the gas-to-liquids process was investigated. It was shown that Moessbauer emission spectroscopy could be used to study the oxidation of cobalt as a deactivation mechanism of high loading cobalt based Fischer-Tropsch catalysts. Oxidation was observed under conditions that are in contradiction with the bulk cobalt phase thermodynamics. This can be explained by oxidation of small cobalt crystallites or by surface oxidation. The formation of re-reducible Co 3+ species was observed as well as the formation of irreducible Co 3+ and Co 2+ species that interact strongly with the alumina support. The formation of the different cobalt species depends on the oxidation conditions. Iron was used as a probe nuclide to investigate the cobalt catalyst preparation procedure. A high-pressure Moessbauer emission spectroscopy cell was designed and constructed, which creates the opportunity to study cobalt based Fischer-Tropsch catalysts under realistic synthesis conditions.

Italian money tested for forgery by moessbauer spectroscopy

International Nuclear Information System (INIS)

Ortalli, I.; Pedrazzi, G.; Jiang Keyu; Zhang Xiufang

1993-01-01

Italian money has been investigated by Moessbauer spectroscopy. The results indicated that the spectrum of a 10000 lire bank-note consisted of three magnetic sextets and two quadrupole doublets, the spectrum of a 5000 lire note consisted of two Zeeman sextets, but in the 'false' money there are two quadrupole doublets only

Moessbauer spectra of some complex compounds of Fe(II) with pyridine

International Nuclear Information System (INIS)

Teodorescu, M.; Filoti, G.

1975-01-01

The Moessbauer spectra of [Fe(II)py 6 ]Br 2 at 298 and 80 K and the reflectance spectra of the same compound at room temperature are presented. Isomer shift and quadrupole splitting were determined for [Fe(II)py 6 ]Br 2 at 298 and 80 K, their values being correlated with those obtained from electronic spectra measured in the solid state. (Z.S.)

Moessbauer study on the distribution of iron vacancies in iron sulfide Fe sub(1-x)S

International Nuclear Information System (INIS)

Igaki, Kenzo; Sato, Masaki; Shinohara, Takeshi.

1982-01-01

The distribution of iron vacancies in iron sulfide Fe sub(1-x)S with the controlled compositions was investigated by Moessbauer spectroscopy at room temperature. Moessbauer spectrum was composed of several component spectra. These component spectra were assigned to the iron atoms with different configurations of neighboring iron vacancies. Judging from the composition dependence of intensity of each component, iron vacancies are considered to lie in every second iron layer for specimens with x between 0.125 and 0.10. For specimens with x between 0.10 and 0.09, this arrangement is nearly kept in the sample quenched from a higher temperature than 473 K, but after annealing at a lower temperature than 473 K iron vacancies are considered to lie not only in every second iron layer but also in every third iron layer or in adjacent iron layers. The iron vacancy arrangement lying in every third iron layer or in adjacent iron layers tends to dominate for specimens with x below 0.09. (author)

Thermal Transformations of Iron Cations in the System Metal-Vitreous Enamel Coat. Moessbauer Spectroscopic Study

International Nuclear Information System (INIS)

Barcova, K.; Mashlan, M.; Zboril, R.; Hrabovska, K.

2005-01-01

Vitreous enameling on steel is carried out to provide a protective layer against chemical corrosion from the surrounding environment. The glass bonds with the steel to form a composite material. The Moessbauer spectroscopy was firstly applied to study the vitreous enameling in which the complex of processes, as diffusion of species, adhesion between the glass and the steel, galvanic reactions, plays an important role. The Moessbauer spectroscopy provides unique information about the Fe-phase structure of the vitreous enamel layer and that of the steel-enamel interface. Diffusion of iron from steel surface towards enamel layer and formation of a new Fe2+ phase was proved

A comparative Moessbauer study of the Nd1+xBa2-x(Cu0.9757Fe0.03)3Oz solid solution: the role of low-temperature treatment

International Nuclear Information System (INIS)

Goodilin, E A; Peryshkov, D V; Presniakov, I A; Didenko, K V; Tretyakov, Yu D

2004-01-01

Local structure features of the Nd 1+x Ba 2-x (Cu 0.97 57 Fe 0.03 ) 3 O z solid solution with various oxygen contents and cation compositions were examined for the first time by Moessbauer spectroscopy to explore the effects of cation disorder in the cases of the anomalous pseudocubic x = 0 phase, the x = 0.6 tetragonal solid solution with Nd stochastically substituting Ba and also the x = 0.9 orthorhombic phase with superstructurally ordered Nd and Ba. A new spectral component characterized by an isomer shift δ = 0 mm s -1 and quadrupole splitting Δ = 0 mm s -1 was found for all the cases, evidencing the formation of associated defects such as 'Fe(IV) Cu1 O 6 -Nd Ba ' and confirming antistructural disordering of Nd 3+ and Ba 2+ in low-T c NdBa 2 Cu 3 O z samples

Moessbauer spectroscopy in Egyptian and Qatari steel industry

International Nuclear Information System (INIS)

Eissa, N.A.

1984-07-01

This paper gives an example of applying the Moessbauer Spectroscopy (MS) in steel industry in both Egypt and Qatar. The author carried out the measurements at the Moessbauer laboratories in Al-Azhar University and in Qatar University. Measurements were carried out on the raw materials and the products. It was possible to check the characteristics of the products at each stage and also the efficiency of its production. The mechanism of formation could be followed. The analysis of M spectra of plain carbon steel provides information on the different phases, reveals the effect of quenching, shows the effect of the interstitial carbon atoms and their movement during tempering. Order disorder transformation, solid solubility limits and texture of materials are mentioned. (author)

A closed cycle-cryostat for high-field Moessbauer spectroscopy

International Nuclear Information System (INIS)

Janoschka, A; Schuenemann, V; Svenconis, G

2010-01-01

A closed cycle-cryostat coupled to a Moessbauer spectrometer has been installed at the University of Kaiserslautern and is in full operation since march 2007. The setup is equipped with a low vibrating two-stage pulse tube cooler and has a cool down time of 48 h. The sample can be top loaded without the need to shut off the refrigerator. With the static helium exchange gas in the variable temperature insert the sample may be cooled down from room temperature to 50 K within several hours. Dynamic exchange gas with external supply of gaseous helium is used to cool the sample down to 2 K. The superconducting self-shielding split-coil generates a magnetic field of up to 5 Tesla and a stray field of ca. 60 mT at the outer cryostat walls. Moessbauer measurements can be performed in perpendicular or parallel field orientations. The sample holder and the Moessbauer drive are rigidly connected to the cryostat. In this way a line width of the two inner α-Fe lines of 0.32 mm/s has been currently achieved.

Synthesis, magnetic properties and Moessbauer spectroscopy for the pyrochlore family Bi{sub 2}BB Prime O{sub 7} with B=Cr and Fe and B Prime =Nb, Ta and Sb

Energy Technology Data Exchange (ETDEWEB)

Blanco, Maria C. [INFIQC (CONICET), Dpto. de Fisicoquimica, Fac. de Ciencias Quimicas, U.N.C., Cordoba (X5000HUA) (Argentina); Franco, Diego G. [INFIQC (CONICET), Dpto. de Fisicoquimica, Fac. de Ciencias Quimicas, U.N.C., Cordoba (X5000HUA) (Argentina); Centro Atomico Bariloche - CNEA, Av. E. Bustillo 9500, S.C. de Bariloche (8500), R.N. (Argentina); Jalit, Yamile; Pannunzio Miner, Elisa V. [INFIQC (CONICET), Dpto. de Fisicoquimica, Fac. de Ciencias Quimicas, U.N.C., Cordoba (X5000HUA) (Argentina); Berndt, Graciele; Paesano, Andrea [Departamento de Fisica, Universidade Estadual de Maringa, Parana (Brazil); Nieva, Gladys [Centro Atomico Bariloche - CNEA, Av. E. Bustillo 9500, S.C. de Bariloche (8500), R.N. (Argentina); Carbonio, Raul E., E-mail: carbonio@mail.fcq.unc.edu.ar [INFIQC (CONICET), Dpto. de Fisicoquimica, Fac. de Ciencias Quimicas, U.N.C., Cordoba (X5000HUA) (Argentina)

2012-08-15

The samples Bi{sub 2}BB Prime O{sub 7}, with B=Cr and Fe and B Prime =Nb, Ta and Sb were prepared by solid state method. The crystallographic structure was investigated on the basis of X-ray powder diffraction data. Rietveld refinements show that the crystal structure is cubic, space group Fd-3m. The Bi{sup 3+} cation on the eight-coordinate pyrochlore A-site shows displacive disorder, as a consequence of its lone pair electron configuration. There is also a considerable A-site disorder shown by Rietveld Analysis and confirmed in the case of the iron containing samples with Moessbauer spectroscopy. The magnetic measurements show paramagnetic behavior at all temperatures for the Cr oxides. The Fe pyrochlores show antiferromagnetic order around 10 K.

Moessbauer investigation of gold-bearing pyrite-rich concentrates

International Nuclear Information System (INIS)

Wagner, F.E.; Harris, D.C.

1994-01-01

A gold-bearing pyrite-rich concentrate of a refractory ore from the Golden Bear mine, northwestern British Columbia, and a pyrite-rich concentrate from Newhawk's west zone, Brucejack Lake area, northern British Columbia, containing 38 and 316 ppm Au and 0.57% and 0.19% As, respectively, have been investigated using 197 Au and 57 Fe Moessbauer spectroscopy. In the Golden Bear sample, the gold is mainly chemically bound in the pyrite with minor amounts present as an Au-Ag alloy, whereas in the Newhawk sample, the gold occurs mainly as an Au-Ag alloy with a composition close to Au 0.5 Ag 0.5 and is only partly bound in the pyrite. Having mean isomer shifts of +3.2 and +4.0 mm/s with respect to a Pt metal source, the gold in pyrite exhibits shifts similar to those observed for gold in arsenopyrite. The nature of the lattice sites occupied by the gold in pyrite is discussed. (orig.)

Characterization of the Carancas-Puno meteorite by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Ceron Loayza, Maria L., E-mail: malucelo@hotmail.com; Bravo Cabrejos, Jorge A. [Universidad Nacional Mayor de San Marcos, Laboratorio de Analisis de Suelos, Facultad de Ciencias Fisicas (Peru)

2011-11-15

We report the results of the study of a meteorite that impacted an inhabited zone on 15 September 2007 in the neighborhood of the town of Carancas, Puno Region, about 1,300 km south of Lima. The analysis carried out by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Moessbauer spectroscopy (at room temperature and at 4.2 K), reveal the presence in the meteorite sample of magnetic sites assigned to taenite (Fe,Ni) and troilite (Fe,S) phases, and of two paramagnetic doublets assigned to Fe{sup 2 + }, one associated with olivine and the other to pyroxene. In accord with these results, this meteorite is classified as a type IV chondrite meteorite.

On the possibilities of age estimation of iron ore minerals using the Moessbauer effect

International Nuclear Information System (INIS)

Mbesherubusa, F.

1980-01-01

The age of geological iron are samples from regions with mainly oxidative conditions has been estimated, by the method of Moessbauer spectroscopy. In many cases the relative age of two samples could be determined unambigiously, due to the different Moessbauer data for Fe 2 + and Fe 3 + and the superparamagnetic behaviour of the iron oxide microcrystallites (up to about 200 A). This has been proved by three series of measurements with samples from three different climatic zones - Baja California, West-Australia, and Rhine Valley. (orig./HBR) [de

Moessbauer effect and vacancy diffusion

International Nuclear Information System (INIS)

Gunther, L.

1976-01-01

A dynamical theory of vacancy diffusion which was motivated by the need to explain recent experimental results for the Moessbauer spectra of Fe in Cu, Fe in Au and Fe in Al is presented. Diffusion in these systems is dominated by the vacancy mechanism, which involves strong correlations between successive jumps. The theory developed by Singwi and Sjoelander for the Moessbauer spectrum of a diffusing nucleus is therefore not applicable. The inverse of the normalized Moessbauer spectrum evaluated at zero frequency is introduced as a useful means of comparing experimental with theoretical spectral widths

Low temperature synthesis, magnetic and electrical properties of iron-magnesium superparamagnetic nanoalloy

Energy Technology Data Exchange (ETDEWEB)

Nazir, Rabia [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Mazhar, Muhammad [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan)], E-mail: mazhar42pk@yahoo.com; Akhtar, Muhammad Javed; Nadeem, Muhammad; Siddique, Muhammad [Physics Division, Pinstech, P.O. Nilore, Islamabad (Pakistan); Shah, Raza [HEJ Research Institute of Chemistry, University of Karachi, Karachi 75270 (Pakistan); Hasanain, S. Khurshid [Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

2009-06-24

A low temperature chemical approach which beats the miscibility barrier of Fe and Mg has been designed to synthesize Fe-Mg{sub 2} nanoalloy and tested to result nanoparticles of average 30 nm size. The nanoalloy is amorphous in nature and characterized by XPRD, AFM, magnetometery, Moessbauer and impedance spectroscopies. The result of magnetic measurement suggests the sample to be superparamagnetic as evidenced by the {sup 57}Fe Moessbauer spectroscopy. The two Mg atoms occupy different positions around iron resulting in two phase system as shown by Moessbauer and impedance spectroscopies.

Low temperature synthesis, magnetic and electrical properties of iron-magnesium superparamagnetic nanoalloy

International Nuclear Information System (INIS)

Nazir, Rabia; Mazhar, Muhammad; Akhtar, Muhammad Javed; Nadeem, Muhammad; Siddique, Muhammad; Shah, Raza; Hasanain, S. Khurshid

2009-01-01

A low temperature chemical approach which beats the miscibility barrier of Fe and Mg has been designed to synthesize Fe-Mg 2 nanoalloy and tested to result nanoparticles of average 30 nm size. The nanoalloy is amorphous in nature and characterized by XPRD, AFM, magnetometery, Moessbauer and impedance spectroscopies. The result of magnetic measurement suggests the sample to be superparamagnetic as evidenced by the 57 Fe Moessbauer spectroscopy. The two Mg atoms occupy different positions around iron resulting in two phase system as shown by Moessbauer and impedance spectroscopies.

Influence of hydrogenation and mechanical grinding on the structural and ferromagnetic properties of GdFeSi

Energy Technology Data Exchange (ETDEWEB)

Chevalier, Bernard; Duttine, Mathieu; Wattiaux, Alain [Universite de Bordeaux, CNRS ICMCB, Pessac (France)

2016-08-01

Hydrogen insertion into GdFeSi induces (i) a structural transition from a tetragonal CeFeSi-type to a tetragonal ZrCuSiAs-type, (ii) an anisotropic expansion of the unit cell parameters because the a parameter decreases, whereas the c parameter increases, and (iii) a decrease in Curie temperature from 121 to 20 K. On the contrary, an amorphous ferromagnet (T{sub C} = 65 K) is obtained by mechanical grinding of GdFeSi. The three compounds (GdFeSi, GdFeSiH, and amorphous GdFeSi) were investigated by {sup 57}Fe Moessbauer spectroscopy. At 4.2 K, this study has revealed that the magnetically ordered Gd substructure produces a small transferred hyperfine magnetic field at the {sup 57}Fe nucleus.

Hyperfine electric parameters calculation in Si samples implanted with {sup 57}Mn→{sup 57}Fe

Energy Technology Data Exchange (ETDEWEB)

Abreu, Y., E-mail: yabreu@ceaden.edu.cu [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Calle 30 No. 502 e/5ta y 7ma Ave., 11300 Miramar, Playa, La Habana (Cuba); Cruz, C.M.; Piñera, I.; Leyva, A.; Cabal, A.E. [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Calle 30 No. 502 e/5ta y 7ma Ave., 11300 Miramar, Playa, La Habana (Cuba); Van Espen, P. [Departement Chemie, Universiteit Antwerpen, Middelheimcampus, G.V.130, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Van Remortel, N. [Departement Fysica, Universiteit Antwerpen, Middelheimcampus, G.U.236, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)

2014-07-15

Nowadays the electronic structure calculations allow the study of complex systems determining the hyperfine parameters measured at a probe atom, including the presence of crystalline defects. The hyperfine electric parameters have been measured by Mössbauer spectroscopy in silicon materials implanted with {sup 57}Mn→{sup 57}Fe ions, observing four main contributions to the spectra. Nevertheless, some ambiguities still remain in the {sup 57}Fe Mössbauer spectra interpretation in this case, regarding the damage configurations and its evolution with annealing. In the present work several implantation environments are evaluated and the {sup 57}Fe hyperfine parameters are calculated. The observed correlation among the studied local environments and the experimental observations is presented, and a tentative microscopic description of the behavior and thermal evolution of the characteristic defects local environments of the probe atoms concerning the location of vacancies and interstitial Si in the neighborhood of {sup 57}Fe ions in substitutional and interstitial sites is proposed.

Ecological aspects of Moessbauer study of iron-containing atmospheric aerosols

International Nuclear Information System (INIS)

Kopcewicz, B.; Kopcewicz, M.

2000-01-01

Moessbauer spectroscopy was applied to analyze the iron compounds in atmospheric aerosol. Seasonal variations of iron concentration in atmospheric air measured over twenty years in Poland are discussed. It was observed that the concentration of iron sulfides (FeS, FeS 2 ) related to coal combustion dropped significantly, however, concentration of iron oxides and iron oxyhydroxides related to fuel combustion increased

57Fe Moessbauer and magnetization study of the Th7Fe3 and the hydride Th7Fe3H/sub n/

International Nuclear Information System (INIS)

Viccaro, P.J.; Shenoy, G.K.; Dunlap, B.D.; Westlake, D.G.; Malik, S.K.; Wallace, W.E.

1978-01-01

Th 7 Fe 3 is known to be a Pauli paramagnet and to undergo a superconducting transition at 1.86K. Its hydride Th 7 Fe 3 H/sub n/ is shown to possess magnetic ordering. The 57 Fe saturated hyperfine field in the hydride is estimated to be aproximately 20kG. A positive isomer shift of 0.30 +- 0.02 mm/s at 300 K relative to Th 7 Fe 3 would be consistent with an increase in d-like electrons on Fe. Preliminary magnetization results indicate a magnetic moment of about 0.5 μ/sub B/ for the hydride and a transition temperature near 300 K

Moessbauer and magnetic susceptibility measurements on M-type hexagonal Ba - ferrite

International Nuclear Information System (INIS)

Lipka, J.; Gruskova, A.; Sitek, J.; Miglierini, M.; Groene, R.; Hucl, M.; Toth, I.; Orlicky, O.

1990-01-01

Samples of stoichiometric BaFe 12 O 19 and Co, Ti substituted barium ferrite were prepared by chemical wet method. Moessbauer spectroscopy, magnetic susceptibility measurements, X-ray diffraction, infrared spectroscopy were conducted to examine the mechanism of formation. The observed magnetic characteristics and electron scanning microscopy show that single domain coprecipitated powders were formed. (orig.)

Moessbauer and EXAFS spectroscopy investigation of iron and arsenic adsorption to lettuce leaves

International Nuclear Information System (INIS)

Vasconcelos, Igor F.; Silva, Gabriela C.; Carvalho, Regina P.; Dantas, Maria Sylvia S.; Ciminelli, Virginia S. T.

2010-01-01

The accumulation of iron and arsenic from aqueous solution by lettuce leaves biomass was investigated using Moessbauer and EXAFS spectroscopic techniques. Moessbauer spectroscopy results show that iron is oxidized during sorption while EXAFS results indicate that iron is coordinated by approximately 6 oxygen and 2 carbon atoms while arsenic is coordinated by approximately 4 oxygen atoms with iron as a second neighbor.

Moessbauer and EXAFS spectroscopy investigation of iron and arsenic adsorption to lettuce leaves

Energy Technology Data Exchange (ETDEWEB)

Vasconcelos, Igor F., E-mail: ifvasco@ufc.br [Universidade Federal do Ceara, Dep. Eng. Metalurgica e de Materiais (Brazil); Silva, Gabriela C.; Carvalho, Regina P.; Dantas, Maria Sylvia S.; Ciminelli, Virginia S. T. [Universidade Federal de Minas Gerais, Dep. Eng. Metalurgica e de Materiais (Brazil)

2010-01-15

The accumulation of iron and arsenic from aqueous solution by lettuce leaves biomass was investigated using Moessbauer and EXAFS spectroscopic techniques. Moessbauer spectroscopy results show that iron is oxidized during sorption while EXAFS results indicate that iron is coordinated by approximately 6 oxygen and 2 carbon atoms while arsenic is coordinated by approximately 4 oxygen atoms with iron as a second neighbor.

Moessbauer effect study on mechanically alloyed amorphous Fe1-xTix alloys

International Nuclear Information System (INIS)

Chen Hong; Xu Zuxiong; Ma Ruzhang; Zhao Zhongtao; Ping Jueyun

1994-01-01

Amorphous Fe 1-x Ti x (x = 0.50, 0.60) powders were produced by mechanical alloying from pure elemental powders in a vibratory ball-mill. X-ray diffraction (XRD) and Moessbauer effect (ME) were used to study the progress of amorphization and the property of hydrogen absorption in Fe-Ti alloys. The amorphization process and the properties of the amorphous phase are discussed. (orig.)

Hyperfine electric parameters calculation in Si samples irradiated with 57Mn

International Nuclear Information System (INIS)

Abreu, Y.; Cruz, C. M.; Pinnera, I.; Leyva, A.; Van Espen, P.; Perez, C.

2011-01-01

The radiation damage created in silicon crystalline material by 57 Mn→ 57 Fe ion implantation was characterized by Moessbauer spectroscopy showing three main lines, assigned to: substitutional, interstitial and a damage configuration sites of the implanted ions. The hyperfine electric parameters, Quadrupole Splitting and Isomer Shift, were calculated for various implantation environments. In the calculations the full potential linearized-augmented plane-wave plus local orbitals (L/APW+lo) method as embodied in the WIEN2k code was used. Good agreement was found between the experimental and the calculated values for some implantation configurations; suggesting that the implantation environments could be similar to the ones proposed by the authors. (Author)

Investigation on Fe-doped ZnO nanostructures prepared by a chemical route

International Nuclear Information System (INIS)

Mishra, A.K.; Das, D.

2010-01-01

Zn 1-x Fe x O (x = 0.03, 0.05 and 0.07) nanoparticles synthesized by a chemical route were characterized by different techniques. The structural characterization by XRD and TEM confirmed the phase purity of the samples and indicated a reduction in particle size with increase in the dopant (Fe) concentration in ZnO. The optical characterization of the nanoparticles by FTIR, PL and UV-visible spectroscopy confirmed the formation of wurtzite structure and incorporation of Fe in the ZnO lattice. Magnetization measurements by VSM and Faraday balance techniques indicate presence of room temperature ferromagnetism in the Fe-doped ZnO samples. Local environment around the Fe atoms has been probed by 57 Fe Moessbauer spectroscopy and the measured isomer shifts confirmed the charge state of iron as Fe 3+ . Positron annihilation lifetime spectroscopy (PALS) measurements confirm the presence of cation vacancies in the nanoparticles and indicate a reduction of overall defect concentration with incorporation of Fe atoms in the ZnO structure.

Chemical-mineralogical characterization and Moessbauer spectroscopy of aquamarine from Pedra Azul, Northeast of Minas Gerais

International Nuclear Information System (INIS)

Viana, Rubia Ribeiro; Jordt-Evangelista, Hanna; Costa, Geraldo Magela da

2001-01-01

Aquamarines from three pegmatites located the vicinities of the Pedra Azul city, Minas Gerais state, were investigated in terms of chemical composition, physical properties and Moessbauer spectroscopy. The small lenticular pegmatite bodies are usually less than 5 m wide and exhibit a conspicuous mineralogical and textural zoning. The last thermal event in these pegmatites, determined by K-Ar method in muscovite, is of Neo proterozoic age, coincident with the late stages of the Brasiliano tectono- metamorphic cycle. Chemical analyses showed that sodium is the alkali with higher contents in the aquamarines, thus enabling their classification as sodic beryls. In zoned samples there is an increase of Fe as well as Mn from center to border, while no systematic variation could be detected for other elements. The specific gravity of 2.72 to 2.80 g/cm 3 is higher than the values determined for samples from other pegmatites of Minas Gerais. The refraction indices are ne=1.569 - 1.579 and NW= 1.573 - 1.581 and the birefringence varies from 0.002 to 0.008. The refraction indices increase with the Be O content. The color of aquamarines varies from medium to light blue, sometimes greenish blue. Moessbauer spectra obtained at room temperature and at 80 K show that Fe 2+ is the main chromophore-ion and suggest that the iron is present in octahedral sites as well as in the structural channels. Moessbauer spectra also indicate that the incorporation of Fe 3+ may cause a shift from deep blue to light blue colors. Based on their aquamarine composition the pegmatites were classified as barren, poor in rare alkalis (Li, Rb, Cs) and therefore little differentiated. The relatively simple mineralogy and the lack of lithium minerals such as lepidolite and spodumene confirm this classification. Thus, the composition of beryl can be used as a tracer for the prospection of pegmatites with different degrees of differentiation and consequently with different types of mineralization. (author)

Comparative Study of Human Liver Ferritin and Chicken Liver by Moessbauer Spectroscopy. Preliminary Results

Energy Technology Data Exchange (ETDEWEB)

Oshtrakh, M. I. [Ural State Technical University - UPI, Division of Applied Biophysics, Faculty of Physical Techniques and Devices for Quality Control (Russian Federation); Milder, O. B.; Semionkin, V. A. [Ural State Technical University - UPI, Faculty of Experimental Physics (Russian Federation); Prokopenko, P. G. [Russian State Medical University, Faculty of Biochemistry (Russian Federation); Malakheeva, L. I. [Simbio Holding, Science Consultation Department (Russian Federation)

2004-12-15

A comparative study of normal human liver ferritin and livers from normal chicken and chicken with Marek disease was made by Moessbauer spectroscopy. Small differences of quadrupole splitting and isomer shift were found for human liver ferritin and chicken liver. Moessbauer parameters for liver from normal chicken and chicken with Marek disease were the same.

Comparative Study of Human Liver Ferritin and Chicken Liver by Moessbauer Spectroscopy. Preliminary Results

International Nuclear Information System (INIS)

Oshtrakh, M. I.; Milder, O. B.; Semionkin, V. A.; Prokopenko, P. G.; Malakheeva, L. I.

2004-01-01

A comparative study of normal human liver ferritin and livers from normal chicken and chicken with Marek disease was made by Moessbauer spectroscopy. Small differences of quadrupole splitting and isomer shift were found for human liver ferritin and chicken liver. Moessbauer parameters for liver from normal chicken and chicken with Marek disease were the same.

Application of Moessbauer spectroscopy to study corrosion

International Nuclear Information System (INIS)

Ramshesh, V.; Ravichandran, K.; Venkateswarlu, K.S.

1976-01-01

The system components in a nuclear power station include steel, stainless steel and various alloys such as Monel, Inconel, Stellite etc. Usually water/heavy water used as the coolant flows at high temperatures and pressures. Under such conditions the interaction of system components with the coolant produces a host of corrosion products. The deposition of such products is essential. This report attempts to review the salient features of identification of such corrosion products using Moessbauer spectroscopy. (author)

Moessbauer-spectroscopic study of structure and magnetism of the exchange-coupled layer systems Fe/FeSn{sub 2}, and Fe/FeSi/Si and the ion-implanted diluted magnetic semiconductor SiC(Fe); Moessbauerspektroskopische Untersuchung von Struktur und Magnetismus der austauschgekoppelten Schichtsysteme Fe/FeSn{sub 2} und Fe/FeSi/Si und des ionenimplantierten verduennten magnetischen Halbleiters SiC(Fe)

Energy Technology Data Exchange (ETDEWEB)

Stromberg, Frank

2009-07-07

In line with this work the structural and magnetic properties of the exchange coupled layered systems Fe/FeSn{sub 2} and Fe/FeSi/Si and of the Fe ion implanted diluted magnetic semiconductor (DMS) SiC(Fe) were investigated. The main measuring method was the isotope selective {sup 57}Fe conversion electron Moessbauer spectroscopy (CEMS), mostly in connection with the {sup 57}Fe tracer layer technique, in a temperature range from 4.2 K to 340 K. Further measurement techniques were X-ray diffraction (XRD), electron diffraction (LEED, RHEED), SQUID magnetometry and FMR (Ferromagnetic Resonance). In the first part of this work the properties of thin AF FeSn{sub 2}(001) films and of the exchange-bias system Fe/FeSn{sub 2}(001) on InSb(001) were investigated. With the application of {sup 57}Fe-tracer layers and CEMS both the Fe-spin structure and the temperature dependence of the magnetic hyperfine field (B{sub hf}) of FeSn{sub 2} could be examined. The evaporation of Fe films on the FeSn{sub 2} films produced in the latter ones a high perpendicular spin component at the Fe/FeSn{sub 2} interface. In some distance from the interface the Fe spins rotate back into the sample plane. Furthermore {sup 57}Fe-CEMS provided a correlation between the absolute value of the exchange field vertical stroke He vertical stroke and the amount of magnetic defects within the FeSn{sub 2}. Temperature dependent CEMS-measurements yielded informations about the spin dynamics within the AF. The transition temperatures T{sub B}{sup *}, which were interpreted as superparamagnetic blocking temperatures, obtain higher values compared to the temperatures T{sub B} of the exchange-bias effect, obtained with magnetometry measurements. The second part of this work deals with the indirect exchange coupling within Fe/FeSi/Si/FeSi/Fe multilayers and FeSi diffusion barriers. The goal was to achieve Fe free Si interlayers. The CEMS results show that starting from a thickness of t{sub FeSi}=10-12 A of the

Moessbauer and infrared spectroscopy as a diagnostic tool for the characterization of ferric tannates

Energy Technology Data Exchange (ETDEWEB)

Jaen, Juan A., E-mail: jjaen@ancon.up.ac.p [Universidad de Panama, Depto. de Quimica Fisica, CITEN, Lab. No. 105, Edificio de Laboratorios Cientificos-VIP (Panama); Navarro, Cesar [Universidad de Panama, Escuela de Quimica, Facultad de Ciencias Naturales, Exactas y Tecnologia (Panama)

2009-07-15

Fourier transform infrared spectroscopy and Moessbauer spectroscopy are use for the characterization and qualitative analysis of hydrolysable and condensed tannates. The two classes of tannates may be differentiated from the characteristic IR pattern. Moessbauer proof that a mixture of mono- and bis-type ferric tannate complexes, and an iron(II)-tannin complex are obtained from the interaction of hydrolysable tannins (tannic acid and chestnut tannin) and condensed tannins (mimosa and quebracho) with a ferric nitrate solution. At pH 7, a partially hydrolyzed ferric tannate complex was also obtained.

Moessbauer and infrared spectroscopy as a diagnostic tool for the characterization of ferric tannates

International Nuclear Information System (INIS)

Jaen, Juan A.; Navarro, Cesar

2009-01-01

Fourier transform infrared spectroscopy and Moessbauer spectroscopy are use for the characterization and qualitative analysis of hydrolysable and condensed tannates. The two classes of tannates may be differentiated from the characteristic IR pattern. Moessbauer proof that a mixture of mono- and bis-type ferric tannate complexes, and an iron(II)-tannin complex are obtained from the interaction of hydrolysable tannins (tannic acid and chestnut tannin) and condensed tannins (mimosa and quebracho) with a ferric nitrate solution. At pH 7, a partially hydrolyzed ferric tannate complex was also obtained.

Moessbauer spectroscopy and nuclear inelastic scattering studies on polynuclear oxo-bridged iron catalyst-first results

International Nuclear Information System (INIS)

Rajagopalan, S.; Asthalter, T.; Rabe, V.; Buerck, U. van; Wagner, F. E.; Laschat, S.

2008-01-01

Polynuclear iron catalysts are interesting materials because of their novel properties. In the future they may help to replace high cost and hazardous heavy metal catalysts by efficient, non toxic and economic iron compounds. In this work, we present some preliminary results on a novel polynuclear oxo-bridged iron catalyst. The chemical environment of the metal species (Fe) was studied under Gif-type conditions (Fe catalyst/Zn/O 2 in pyridine/acetic acid) with cyclohexene as substrate. Such Gif-type catalysts are able to catalyse the selective oxidation of alkanes and alkenes. The characterization was done by Moessbauer spectroscopy and nuclear inelastic scattering. In order to identify the intermediate species during the reaction (selective oxidation using molecular O 2 ), a freeze-quench technique was used. This also helps to understand the kinetics of the chemical reaction.

Mineral identification in Colombian coals using Moessbauer spectroscopy and X-ray diffraction

International Nuclear Information System (INIS)

Fajardo, M.; Mojica, J.; Barraza, J.; Perez Alcazar, G.A.; Tabares, J.A.

1999-01-01

Minerals were identified in three Colombian coal samples from the Southwest of the country using Moessbauer spectroscopy and X-ray diffraction. Original and sink separated coal fractions of specific gravity 1.40 and 1.60 with particle size less than 600 μm were used in the study. Using Moessbauer spectroscopy, the minerals identified in the original coal samples were pyrite jarosite, ankerite, illite and ferrous sulfate, whereas by means of X-ray diffraction, minerals identified were kaolinite, quartz, pyrite, and jarosite. Differences in mineral composition were found in the original and sink separated fractions using both techniques. Moessbauer spectra show that the mineral phases in low concentrations such as illite, ankerite and ferrous sulfate do not always appear in the spectra of sink coals, despite of those minerals occurring in the original coal, due to the fact that they are associated with the organic matter and not liberated in the grinding process. X-ray results show that the peak intensity grows as the specific gravity is increased indicating that the density separation method could be an effective process to clean coal

Moessbauer study of El-Bahrain meteorite

International Nuclear Information System (INIS)

Bahgat, A.A.; Ahmed, M.A.; Ramadan, T.M.

2000-01-01

A stone of brick-like shape, measuring roughly 25 x 12.5 x 10.5 cm 3 and weighing 14 kg was found in 1983, in the western desert of Egypt. The meteorite was named El-Bahrain meteorite and classified as L-chondrite. Principal constituents of El-Bahrain meteorite have been studied by means of Moessbauer spectroscopy. The chemical composition as obtained by the conventional wet analyses of L-chondritic meteorites showed that the meteorite contains 23,38% Fe and 1.23% Ni. While the analysis of the atomic absorption showed the presence of 27.03% as a total iron. The Moessbauer analysis of El-Bahrain meteorite showed that the iron constituent minerals were determined to be olivine, metallic iron-nickel alloys (kamacite, taenite and tetrataenite), ferrous sulfide (troilite) and weathering products such as maghemite and nanocrystalline hematite. The structure of meteoritic iron obtained by the Moessbauer analysis has been discussed on the basis of these constituents. (author)

Positron lifetime and Moessbauer study of Fe80-xNixB20 metallic glasses

International Nuclear Information System (INIS)

Baluch, S.; Miglierini, M.; Groene, R.; Sitek, J.

1989-01-01

In order to investigate the short-range order (SRO) of iron-rich Fe 80-x Ni x B 20 (x = 10, 20, 30, 40) metallic glasses positron lifetime and Moessbauer measurements were carried out. Positron lifetimes of samples and Moessbauer hyperfine structure data of neutron-irradiated samples as functions of nickel content are shown and discussed. Results give evidence that high Ni content stabilizes the structure and can be connected with a higher degree of SRO in metallic glasses

Moessbauer studies of the LiAl sub(5-x) Fe sub(x) O8 and LiGa sub(5-x) Fe sub(x) O8 systems

International Nuclear Information System (INIS)

Barthem, V.M.T.S.; Maria Neto, J.; Souza Barros, F. de

1982-01-01

Comparative Moessbauer studies of the LiGa sub(5-x) Fe sub(x) O 8 and LiAl sub(5-x) Fe sub(x) O 8 systems are shown. The characteristics of the Moessbauer spectra, obtained with LiGa 5 O 8 samples with 0,1% of Fe 3+ , differ drastically from that observed with LiAl 5 O 8 with the same three-valent iron concentration. All these differences are related to the more covalent character of the gallium-oxygen binding, when compared with the aluminium-oxygen one. (L.C.) [pt

Applications of Moessbauer spectroscopy in the study of minerals: some recent trends

International Nuclear Information System (INIS)

Danon, J.

1983-01-01

Three examples of mineralogy studies in which Moessbauer spectrsocopy is playing a determinant role: magnetic order in silicates, biomineralization of iron by bacteria and order-disorder transitions in Fe-Ni alloys in meteorites are discussed. (L.C.) [pt

The influence of Zn-dopant on the precipitation of α-FeOOH in highly alkaline media

International Nuclear Information System (INIS)

Krehula, Stjepko; Music, Svetozar; Skoko, Zeljko; Popovic, Stanko

2006-01-01

The influence of Zn-dopant on the precipitation of α-FeOOH in highly alkaline media was monitored by X-ray diffraction (XRD), 57 Fe Moessbauer and Fourier transform infrared (FT-IR) spectroscopies and field emission scanning electron microscopy (FE SEM). Acicular and monodisperse α-FeOOH particles were precipitated at a very high pH by adding a tetramethylammonium hydroxide solution to an aqueous solution of FeCl 3 . The XRD analysis of the samples precipitated in the presence of Zn 2+ ions showed the formation of solid solutions of α-(Fe, Zn)OOH up to a concentration ratio r = [Zn]/([Zn] + [Fe]) = 0.0909. ZnFe 2 O 4 was additionally formed in the precipitate for r = 0.1111, whereas the three phases α-FeOOH, α-Fe 2 O 3 and ZnFe 2 O 4 were formed for r 0.1304. In the corresponding FT-IR spectra, the Fe-OH and Fe-O stretching bands were sensitive to the Zn 2+ substitution, whereas the Fe-OH bending bands of α-FeOOH at 892 and 796 cm -1 were almost insensitive. The Moessbauer spectra showed a high sensitivity to the formation of α-(Fe, Zn)OOH solid solutions which were monitored on the basis of a decrease in B hf values in dependence on Zn-doping. A strictly linear decrease in B hf for α-FeOOH doped with Zn 2+ ions was measured up to r = 0.0291, whereas for r = 0.0476 and higher there was a deviation from linearity. The presence of α-(Fe, Zn)OOH, α-Fe 2 O 3 and ZnFe 2 O 4 phases in the samples was determined quantitatively by Moessbauer spectroscopy. Likewise, Moessbauer spectroscopy did not show any formation of the solid solutions of α-Fe 2 O 3 with Zn 2+ ions. FE SEM showed a strong effect of Zn-doping on the elongation of acicular α-FeOOH particles (∼500-700 nm in length) up to r = 0.1111. For r = 0.1304 the sizes of ZnFe 2 O 4 particles were around 30-50 nm, and those of α-Fe 2 O 3 particles were around 500 nm, whereas a relatively small number of very elongated α-(Fe, Zn)OOH particles was observed. A possible mechanism of the formation of α-(Fe

The elementary concentration and the behavior of the iron in Cuban agricultural soils by means of the Neutron activation Analysis and Moessbauer Spectroscopy

International Nuclear Information System (INIS)

Furet, N. R.; Oddone, M.; Orihuela, D.L.

1999-01-01

Representative samples from Cuban agricultural soils, which have been benefited with industrial waste are studied by means of the methods of the Analysis for Instrumental Neutronic Activation and Moessbauer Spectroscopy. The elemental contents of Na, K, Ca, Fe, Cr, etc. are determined, and the influence of the industrial waste in the elemental concentrations is valued. The behavior of the iron is studied, like one of the important elements in several processes of development of the plants. The oxidation and coordination states of the Fe in soils are studied

Moessbauer Spectroscopy in the Characterization of waste product used like fertilizer in soil. Some Applications

International Nuclear Information System (INIS)

Furet, N. R.; Orihuela, D. L.; Hernandez

2007-01-01

At the present time, the use of industrial solid wastes is an important task, because a great effort that have been carried out to preserve the environmental and to obtain the high technologies. In this work, a characterization of a industrial waste product, on base of the monohydrous iron sulphate (FeSO 4 .1H 2 O) with a 15% approximately of free sulphuric acid, used like improvement of soil was carried out by Mossabuer spectroscopy. This waste product was used in a series of the experiences in parcels (where peaches, (Prunus persica), strawberries are cultivated) in the zone of Cartaya (Huelva, Spain). The characterisation of soil from the parcel before application of this product was carried out in order to analyse and compare with the final results by using the methods of the Moessbauer spectroscopy. High contents of Fe, S, and Zn at the studied product are observed . This elements are very important for plants. The pH in soil and Fe, Mn, and Zn contents in soil and leaf were determined. The knowledge of the main chemical-structural properties of this product, used like improvement of soil, will permit the study of the influence to) on the soil properly, b) on the peach leaves and c) on the foodstuff fruit. (Author)

Moessbauer study of hemoglobin of diabetes

International Nuclear Information System (INIS)

Li Aiguo; Ni Xinbo; Cai Yingwen; Zhang Guilin; Zhang Hongde; Ge Yongxin

2000-01-01

The hemoglobins from normal adults (Gly-Hb 5%), people infected with diabetes (Gly-Hb 10%) and serious diabetics (Gly-Hb 15%) were investigated by Moessbauer spectroscopy at liquid nitrogen temperature. All the experimental spectra of hemoglobin are composed of three doublets corresponding to oxy-hemoglobin (Oxy-Hb), deoxy-hemoglobin (Deoxy-Hb) and low-spin hemo-chrome (Ls-Hemo) respectively. It is found that Oxy-Hb is decreasing but Deoxy-hb increasing for diabetes. Experimental results also indicate that the line-width of Moessbauer spectra of Oxy-Hb for diabetics is narrower than that for normal adults, showing that while Fe on Oxy-Hb exists in pile-up of some similar states for normal adults, but it becomes in single state for serious diabetes

In situ 119Sn Moessbauer spectroscopy used to study lithium insertion in c-Mg2Sn

International Nuclear Information System (INIS)

Aldon, L.; Ionica, C. M.; Lippens, P. E.; Larcher, D.; Tarascon, J.-M.; Olivier-Fourcade, J.; Jumas, J.-C.

2006-01-01

The electrochemical reactions of Li with c-Mg 2 Sn have been investigated by in situ Moessbauer spectroscopy of 119 Sn and X-ray diffraction. The lithiation transforms initially c-Mg 2 Sn part into Li x Mg 2 Sn alloy (x 2 MgSn ternary alloy. In situ Moessbauer spectroscopy provides valuable information on local environment of tin and swelling behavior and cracking of the particles during discharge and charge processes.

Application of Moessbauer spectroscopy to the study of neptunium adsorbed on deep-sea sediments

International Nuclear Information System (INIS)

Bennett, B.A.; Rees, L.V.C.

1987-03-01

A Neptunium Moessbauer spectrometer (the first in Great Britain) was constructed and the Moessbauer spectra of NpAl Laves phase alloy obtained. Neptunium was sorbed onto a calcareous deep-sea sediment from sea water, using a successive-loading technique. Sorption appeared to be by an equilibrium reaction, and because of the low solubility of neptunium in seawater, this meant that the maximum loading that could be achieved was 8mg 237 Np/g sediment. This proved to be an adequate concentration for Moessbauer measurements and a Moessbauer spectrum was obtained. This showed that most of the neptunium was in exchange sites and not present as precipitates of neptunium compounds. It was probably in the 4+ state indicating that reduction had occurred during sorption. This work has demonstrated that Moessbauer Spectroscopy has great potential as an aid to understanding the mechanism of actinide sorption in natural systems. (author)

Electronic properties of Fe2+ in MTiO3

International Nuclear Information System (INIS)

Ito, A.; Morimoto, S.

1975-01-01

Moessbauer spectra were observed in a temperature range from 4.2 to 300 K for the ilmenite structure compounds MTiO 3 -2 % 57 Fe (M = Mg, Mn-I, Fe, Co, Ni) and for the disordered ilmenite structure compound MnTiO 2 -II-1 % 57 Fe. The Neel temperature and the spin orientation of host materials are tabulated. A well resolved quadrupole doublet was observed for all the samples at temperatures above the respective Neel temperatures. Below the Neel temperature a magnetic structure appeared. The Moessbauer spectra obtained at 4.2 K are presented. The spectra were analyzed on the basis of the well-known Hamiltonian for sup(57m)Fe. Moessbauer parameters obtained are tabulated. Analyzing the spectra at 4.2 K, quadrupole interaction was determined to be negative in MnTiO 3 -II and positive in all other compounds. Hyperfine magnetic field intensities observed a6 4.2 K were 34, 85, 47, 105 and 91 kOe for MnTiO 3 -I, MnTiO 3 -II, FeTiO 3 , CoTiO 3 and NiTiO 3 , respectively. (Z.S.)

In-situ Moessbauer spectroscopy with MIMOS II

Energy Technology Data Exchange (ETDEWEB)

Fleischer, Iris, E-mail: fleischi@uni-mainz.de; Klingelhoefer, Goestar [Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University of Mainz (Germany); Morris, Richard V. [NASA Johnson Space Center (United States); Schroeder, Christian [University of Bayreuth and University of Tuebingen (Germany); Rodionov, Daniel [Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University of Mainz (Germany); Souza, Paulo A. de [Tasmanian ICT Centre (Australia); Collaboration: MIMOS II Team

2012-03-15

The miniaturized Moessbauer spectrometer MIMOS II was developed for the exploration of planetary surfaces. Two MIMOS II instruments were successfully deployed on the martian surface as payload elements of the NASA Mars Exploration Rover (MER) mission and have returned data since landing in January 2004. Moessbauer spectroscopy has made significant contributions to the success of the MER mission, in particular identification of iron-bearing minerals formed through aqueous weathering processes. As a field-portable instrument and with backscattering geometry, MIMOS II provides an opportunity for non-destructive in-situ investigations for a range of applications. For example, the instrument has been used for analyses of archaeological artifacts, for air pollution studies and for in-field monitoring of green rust formation. A MER-type MIMOS II instrument is part of the payload of the Russian Phobos-Grunt mission, scheduled for launch in November 2011, with the aim of exploring the composition of the martian moon Phobos. An advanced version of the instrument, MIMOS IIA, that incorporates capability for elemental analyses, is currently under development.

Temperature dependence of the Moessbauer spectra of amorphous and nanocrystallized Fe86Zr7Cu1B6

International Nuclear Information System (INIS)

Orue, I.; Gorria, P.; Plazaola, F.; Fernandez-Gubieda, M.L.; Barandiaran, J.M.

1994-01-01

Moessbauer measurements have been performed on amorphous and nanocrystalline alloy ribbons of nominal composition Fe 86 Zr 7 Cu 1 B 6 . The nanocrystalline samples were obtained by annealing the as-quenched alloy at different temperatures in the range between 650 and 870 K. Moessbauer spectra of the as-quenched amorphous sample have been recorded at 77 K, room temperature and above the Curie temperature (∼ 330 K) at 360 K. We have also performed Moessbauer measurements at room temperature in the nanocrystalline alloys to characterize the phases that appear after the annealing and their relative concentration. The as-quenched sample spectra reveal the existence of two inequivalent sites for Fe. Such a feature is also observed in the remaining amorphous phase of the annealed samples. In the first steps of crystallization, α-Fe precipitates and its concentration increases with the annealing temperature. The experimental results suggest that the composition of the whole amorphous phase does not suffer large changes during crystallization. (orig.)

Hyperfine interactions in dilute Se doped Fe{sub x}Sb{sub 1−x} bulk alloy

Energy Technology Data Exchange (ETDEWEB)

Sarkar, Mitesh, E-mail: miteshsarkar-msu@yahoo.com; Agrawal, Naveen [The M. S. University of Baroda, Department of Physics (India); Chawda, Mukesh [Polytechnic, The M. S. University of Baroda, Department of Applied Physics (India)

2016-12-15

Hyperfine Interaction technique like Moessbauer spectroscopy is a very sensitive tool to study the local probe interactions in Iron doped alloys and compounds. We report here the Moessbauer study of the effect of Fe concentration variations in dilute magnetic semiconducting Se{sub 0.004}Fe{sub x}Sb{sub 1−x} alloys for x = 0.002, 0.004 and 0.008. The materials were characterized using X-ray diffraction technique (XRD), Fourier Transform Infra-red spectroscopy (FTIR), Neutron depolarization and Moessbauer spectroscopy. The FTIR result shows the semiconducting behavior of the alloys with band gap of 0.18 eV. From Moessbauer spectroscopy two magnetic sites (A and B) were observed. The value of hyperfine magnetic fields (HMF) of ∼ 308 kOe (site A) and 270 kOe (site B) was constant with increase in Fe concentration. A nonmagnetic interaction was also observed with quadrupole splitting (QS) of 1.26 mm/sec (site C) for x = 0.004 and x = 0.008. The Neutron depolarization studies indicate that the clusters of Fe or Fe based compounds having net magnetic moments with a size greater than 100 Å is absent.

Application of Moessbauer spectroscopy in investigating Egyptian archaeology

International Nuclear Information System (INIS)

Eissa, N.A.; Sallam, H.A.

1988-01-01

This article summarizes the results of applications of the Moessbauer spectroscopy to investigate Ancient Egyptian pottery from the periods: Ancient Egyptian (3200-525 B.C.), Greek-Roman (320 B.C.-640 A.C.) and Early Islamic (800-1000 A.C.). Many objective informations deduced about: provinance, manufacturing techniques for different domestic purposes, civilization transfer between the Arab countries, methods of colouration and applying decorating glazes, and finally dating of ancient pottery. (orig.)

Moessbauer studies of a martensitic transformation and of cryogenic treatments of a D2 tool steel

Energy Technology Data Exchange (ETDEWEB)

Costa, B. F. O., E-mail: benilde@ci.uc.pt [University of Coimbra, CEMDRX, Department of Physics (Portugal); Blumers, M. [University Mainz, Institute of Inorganic Chemistry (Germany); Kortmann, A. [Ingpuls GmbH (Germany); Theisen, W. [Ruhr-Universitaet Bochum, Institute of Materials (Germany); Batista, A. C. [University of Coimbra, CEMDRX, Department of Physics (Portugal); Klingelhoefer, G. [University Mainz, Institute of Inorganic Chemistry (Germany)

2013-04-15

A D2 tool steel X153CrVMo12 with composition C1.53 Cr12 V0.95 Mo0.80 Mn0.40(wt% Fe balanced) was studied by use of Moessbauer spectroscopy and X-ray diffraction. It was observed that the study of carbides by X-ray diffraction was difficult while Moessbauer spectroscopy gives some light on the process occurring during cryogenic treatment. With the increase of the martensitic phase the carbides decrease and are dissolved in solid solution of martensite as well as the chromium element.

Fe++/Fe+++ concentration relationship and mechanical properties of phosphate glasses useful for wastes immobilization

International Nuclear Information System (INIS)

Garcia, D.A.; Prado, Miguel O.

2007-01-01

Under different melting conditions, glasses with different Fe(II)/Fe(III) concentration relationship were prepared within each type of glass 43Fe 2 O 3 -57P 2 O 5 and 33,33Fe 2 O 3 - 66,67P 2 O 5 . Using Moessbauer spectroscopy Fe(II)/Fe(III) concentration values were determined. Vickers and Knoop indentations were used for determining their hardness, toughness, Young modulus and brittleness. The same measurements were carried on some silicate and aluminosilicate glasses. Also Weibull statistics was done to determine the characteristics (Weibull modulus and and fracture probability) of glass fracture. We found that silicate glasses (SG) are harder than phosphate glasses (PG). Toughness values for PG, are in the same range than for SG, although for the same density exhibit larger values or smaller brittleness than silicate glasses. For one of the glasses it was found that the mechanical load P 0 needed for a fracture probability of 63% increases with the Fe(II) content. (author)

Thermal treatment of the Fe{sub 78} Si{sub 9} B{sub 13} alloy and the analysis of it magnetic properties through Moessbauer spectroscopy and Positronium annihilation; Tratamiento termico de la aleacion Fe{sub 78} Si{sub 9} B{sub 13} y el analisis de sus propiedades magneticas mediante Espectroscopia de Moessbauer y Aniquilacion de positronio

Energy Technology Data Exchange (ETDEWEB)

Lopez M, A

2005-07-01

The present work is divided in five chapters. In the first one a general vision of the amorphous alloys is given from antecedents, structure, obtaining methods, properties and problems that at the moment, focusing us in a certain moment to the iron base alloys and the anomalous problem of hardness that it presents the alloy Fe{sub 78}Si{sub 9}B{sub 13} like previously mention us. The second chapter tries on the basic theory of the techniques of Moessbauer spectroscopy and Positron Annihilation spectroscopy, used for the characterization of our alloy as well as the complementary technique of X-ray diffraction (XRD) to observe that the amorphous phase was even studying. The third chapter describes the experimental conditions that were used to study the alloy Fe{sub 78}Si{sub 9}B{sub 13} in each one of their thermal treatments. In the fourth chapter the obtained results and their discussion are presented. In the fifth chapter the conclusions to which were arrived after analyzing the results are presented. (Author)

Characterization of mineral phases of agricultural soil samples of Colombian coffee using Moessbauer spectroscopy and X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, Humberto Bustos, E-mail: hbustos@ut.edu.co; Lozano, Dagoberto Oyola; Martinez, Yebrayl Antonio Rojas; Pinilla, Marlene Rivera [Universidad del Tolima, Grupo Ciencia de Materiales y Tecnologia en Plasma (Colombia); Alcazar, German Antonio Perez [Universidad del Valle, Grupo Metalurgia Fisica y Teoria de las Transiciones de Fase (Colombia)

2012-03-15

Soil chemical analysis, X-ray diffraction (XRD) and Moessbauer spectrometry (MS) of {sup 57}Fe were used to characterize mineral phases of samples taken from the productive layer (horizon A) of agricultural coffee soil from Tolima (Colombia). Chemical analysis shows the chemical and textural parameters of samples from two different regions of Tolima, i.e., Ibague and Santa Isabel. By XRD phases like illite (I), andesine (A) and quartz (Q) in both samples were identified. The quantity of these phases is different for the two samples. The MS spectra taken at room temperature were adjusted by using five doublets, three of them associated to Fe{sup + 3} type sites and the other two to Fe{sup + 2} type sites. According to their isomer shift and quadrupole splitting the presence of phases like illite (detected by DRX), nontronite and biotite (not detected by XRD) can be postulated.

Implementation of the Electron conversion Moessbauer spectroscopy

International Nuclear Information System (INIS)

Hernandez, Torres, D.; Noriega Scull, C.

1996-01-01

In the present work has been exposed the principles of the Conversion Moessbauer Electron Spectroscopy and its possibilities of application. Is also described the operation of the parallel plate avalanche detector made at the CEADEN starting from modifications done to the Gancedo's model and is exposed examples of the use of this detector in the characterization of corroded surfaces, with chemical cleaning and in samples of welded joints. The experiences obtained of this work were extended to the National Polytechnic Institute of Mexico where a similar detector, made in our center, was installed there

Application of Moessbauer spectroscopy in studies of thermal fatigue of ceramic materials. Part of a coordinated programme on development of methods for the application of Moessbauer spectroscopy in mineralogy, soil sciences and ceramics

International Nuclear Information System (INIS)

Gangas, A.H.

1980-10-01

Moessbauer measurements have been carried out on powder samples of pseudobrookite (Fe 2 TiO 5 ) which is known to exhibit extensive microcracking due to its highly anisotropic thermal expansion. The samples were subjected to temperature cycling treatment either at high (30 to 450 C) or low (-130 to 120 C) temperature range. It was observed that the crystal lattice vibrations are changing in response to the thermal fatigue treatment applied. Measurements of isomer shift and Moessbauer spectral areas allows to determine the characteristic Debye temperature which depends on the type of temperature treatment used, the findings are in qualitative agreement with the existence of a critical grain size for the microcracking of Fe 2 TiO 5 as found in elastic modules and flexural strength measurements

Interlayer exchange coupling, crystalline and magnetic structure in Fe/CsCl-FeSi multilayers grown by molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Dekoster, J.; Degroote, S.; Meersschaut, J.; Moons, R.; Vantomme, A. [K.U. Leuven, Instituut voor Kern- en Stralingsfysica (Belgium); Bottyan, L.; Deak, L.; Szilagyi, E.; Nagy, D.L. [KFKI Research Institute for Particle and Nuclear Physics (Hungary); Baron, A.Q.R. [European Synchrotron Radiation Facility (France); Langouche, G. [K.U. Leuven, Instituut voor Kern- en Stralingsfysica (Belgium)

1999-09-15

Crystalline and magnetic structure as well as the interlayer exchange coupling in MBE grown Fe/FeSi multilayers are investigated. From conversion electron Moessbauer spectroscopy and ion beam channeling measurements the spacer FeSi material is found to be stabilized in a crystalline metastable metallic FeSi phase with the CsCl structure. Strong non-oscillatory interlayer exchange coupling is identified with magnetometry and synchrotron Moessbauer reflectometry. From the fits of the time spectrum and the resonant {phi}-{phi} scans a model for the sublayer magnetization of the multilayer is deduced.

Investigation on Fe-doped ZnO nanostructures prepared by a chemical route

Energy Technology Data Exchange (ETDEWEB)

Mishra, A.K. [UGC-DAE Consortium for Scientific Research, Kolkata Centre III/LB-8, Bidhannagar, Kolkata 700098 (India); Das, D., E-mail: ddas@alpha.iuc.res.in [UGC-DAE Consortium for Scientific Research, Kolkata Centre III/LB-8, Bidhannagar, Kolkata 700098 (India)

2010-07-25

Zn{sub 1-x}Fe{sub x}O (x = 0.03, 0.05 and 0.07) nanoparticles synthesized by a chemical route were characterized by different techniques. The structural characterization by XRD and TEM confirmed the phase purity of the samples and indicated a reduction in particle size with increase in the dopant (Fe) concentration in ZnO. The optical characterization of the nanoparticles by FTIR, PL and UV-visible spectroscopy confirmed the formation of wurtzite structure and incorporation of Fe in the ZnO lattice. Magnetization measurements by VSM and Faraday balance techniques indicate presence of room temperature ferromagnetism in the Fe-doped ZnO samples. Local environment around the Fe atoms has been probed by {sup 57}Fe Moessbauer spectroscopy and the measured isomer shifts confirmed the charge state of iron as Fe{sup 3+}. Positron annihilation lifetime spectroscopy (PALS) measurements confirm the presence of cation vacancies in the nanoparticles and indicate a reduction of overall defect concentration with incorporation of Fe atoms in the ZnO structure.

A microprocessor based multiscaling data acquisition system for moessbauer spectroscopy

International Nuclear Information System (INIS)

Bohm, C.; Ekdahl, T.

1985-01-01

A microprocessor based data acquisition system is described, which was developed for use in Moessbauer spectroscopy. It is designed to record two spectra simultaneously, one of which could be a calibration spectrum. It is autonomous, but uses a host computer for initialization and permanent storage of data. The host communication software is also described. (Author)

Iron valence in double-perovskite (Ba,Sr,Ca)2FeMoO6: isovalent substitution effect

International Nuclear Information System (INIS)

Yasukawa, Y.; Linden, J.; Chan, T.S.; Liu, R.S.; Yamauchi, H.; Karppinen, M.

2004-01-01

In the Fe-Mo based B-site ordered double-perovskite, A 2 FeMoO 6.0 , with iron in the mixed-valence II/III state, the valence value of Fe is not precisely fixed at 2.5 but may be fine-tuned by means of applying chemical pressure at the A-cation site. This is shown through a systematic 57 Fe Moessbauer spectroscopy study using a series of A 2 FeMoO 6.0 [A=(Ba,Sr) or (Sr,Ca)] samples with high degree of Fe/Mo order, the same stoichiometric oxygen content and also almost the same grain size. The isomer shift values and other hyperfine parameters obtained from the Moessbauer spectra confirm that Fe remains in the mixed-valence state within the whole range of A constituents. However, upon increasing the average cation size at the A site the precise valence of Fe is found to decrease such that within the A=(Ba,Sr) regime the valence of Fe is closer to II, while within the A=(Sr,Ca) regime it is closer to the actual mixed-valence II/III state. As the valence of Fe approaches II, the difference in charges between Fe and Mo increases, and parallel with this the degree of Fe/Mo order increases. Additionally, for the less-ordered samples an increased tendency of clustering of the antisite Fe atoms is deduced from the Moessbauer data

{sup 57}Fe Emission Mössbauer Study on Gd{sub 3}Ga{sub 5}O{sub 12} implanted with dilute{sup 57}Mn

Energy Technology Data Exchange (ETDEWEB)

Krastev, P. B. [Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy (Bulgaria); Gunnlaugsson, H. P., E-mail: haraldur.p.gunnlaugsson@cern.ch [CERN (Switzerland); Nomura, K. [Tokyo University of Science (Japan); Adoons, V. [University of Zululand, Physics and Engineering Department (South Africa); Gerami, A. M.; Johnston, K. [CERN (Switzerland); Ncube, M. [University of the Witwatersrand, School of Physics (South Africa); Mantovan, R. [IMM-CNR, Laboratorio MDM (Italy); Masenda, H. [University of the Witwatersrand, School of Physics (South Africa); Matveyev, Y. A. [Moscow Institute of Physics and Technology (Russian Federation); Mølholt, T. E. [CERN (Switzerland); Unzueta, I. [Euskal Herriko Unibertsitatea (UPV/EHU), BCMaterials & Elektrizitate eta Elektronika Saila (Spain); Bharuth-Ram, K. [Durban University of Technology, Physics Department (South Africa); Gislason, H. [University of Iceland, Science Institute (Iceland); Langouche, G. [University of Leuven, Instituut voor Kern- en Stralingsfysika (Belgium); Naidoo, D. [University of the Witwatersrand, School of Physics (South Africa); Ólafsson, S. [University of Iceland, Science Institute (Iceland); Collaboration: the ISOLDE collaboration

2016-12-15

{sup 57}Fe emission Mössbauer spectroscopy has been applied to study the lattice location and properties of Fe in gadolinium gallium garnet Gd{sub 3}Ga{sub 5}O{sub 12} (GGG) single crystals in the temperature interval 300 – 563 K within the extremely dilute (<10{sup −4} at.%) regime following the implantation of{sup 57}Mn (T{sup 1}{sub /2}= 1.5 min.) at ISOLDE/CERN. These results are compared with earlier Mössbauer spectroscopy study of Fe-doped gadolinium gallium garnet Gd{sub 3}Ga{sub 5}O{sub 12}(GGG), with implantation fluences between 8×10{sup 15} and 6×10{sup 16} atoms cm{sup −2}. Three Fe components are observed in the emission Mössbauer spectra: (i) high spin Fe{sup 2+} located at damage sites due to the implantation process, (ii) high spin Fe{sup 3+} at substitutional tetrahedral Ga sites, and (iii) interstitial Fe, probably due to the recoil imparted on the daughter{sup 57∗}Fe nucleus in the β{sup −} decay of{sup 57}Mn. In contrast to high fluence{sup 57}Fe implantation studies the Fe{sup 3+} ions are found to prefer the tetrahedral Ga site over the octahedral Ga site. No annealing stages are evident in the temperature range investigated. Despite the very low concentration, high-spin Fe{sup 3+} shows fast spin relaxation, presumably due to an indirect interaction between nearby gadolinium atoms.

Moessbauer and X-ray Diffraction Investigations of Sn-containing Binary and Ternary Electrodeposited Alloys from a Gluconate Bath

International Nuclear Information System (INIS)

Kuzmann, E.; Stichleutner, S.; Homonnay, Z.; Vertes, A.; Doyle, O.; Chisholm, C.U.; El-Sharif, M.

2005-01-01

Constant current technique was applied to electrodeposit tin-containing coatings such as tin-cobalt (Sn-Co), tin-iron (Sn-Fe) and a novel tin-cobalt-iron (Sn-Co-Fe) from a gluconate bath. The effect of plating parameters (current density, deposition time at an electrolyte temperature of 60 deg. C and pH=7.0) on phase composition, crystal structure and magnetic anisotropy of alloy deposits has been investigated mainly by 57Fe CEMS, 119Sn CEMS and transmission Moessbauer Spectroscopy as well as XRD. 57Fe and 119Sn CEM spectra and XRD reflect that the dominant phases of the deposits are orthorhombic Co3Sn2, tetragonal FeSn2 or amorphous Fe-Sn and amorphous Sn-Co-Fe in Sn-Co, Sn-Fe and Sn-Co-Fe coatings, respectively. Furthermore, the relative area of the 2nd and 5th lines of the sextets representing the magnetic iron containing phases decreases continuously with increasing current density in all Fe-containing deposits. At the same time, no essential change in the magnetic anisotropy can be found with the plating time. 119Sn spectra reveal the presence of small amount of β-Sn besides the main phases in Sn-Fe and in the Sn-Co coatings. Magnetically split 119Sn spectra reflecting transferred hyperfine field were observed in the case of Co-Sn-Fe coatings

Moessbauer and X-ray Diffraction Investigations of Sn-containing Binary and Ternary Electrodeposited Alloys from a Gluconate Bath

Energy Technology Data Exchange (ETDEWEB)

Kuzmann, E; Stichleutner, S; Homonnay, Z; Vertes, A [Department of Nulear Chemistry, Hungarian Academy of Sciences, Eoetvoes University, Budapest (Hungary); Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Eoetvoes University, Budapest (Hungary); Doyle, O; Chisholm, C U; El-Sharif, M [Glasgow Caledonian University, Glasgow, Scotland (United Kingdom)

2005-04-26

Constant current technique was applied to electrodeposit tin-containing coatings such as tin-cobalt (Sn-Co), tin-iron (Sn-Fe) and a novel tin-cobalt-iron (Sn-Co-Fe) from a gluconate bath. The effect of plating parameters (current density, deposition time at an electrolyte temperature of 60 deg. C and pH=7.0) on phase composition, crystal structure and magnetic anisotropy of alloy deposits has been investigated mainly by 57Fe CEMS, 119Sn CEMS and transmission Moessbauer Spectroscopy as well as XRD. 57Fe and 119Sn CEM spectra and XRD reflect that the dominant phases of the deposits are orthorhombic Co3Sn2, tetragonal FeSn2 or amorphous Fe-Sn and amorphous Sn-Co-Fe in Sn-Co, Sn-Fe and Sn-Co-Fe coatings, respectively. Furthermore, the relative area of the 2nd and 5th lines of the sextets representing the magnetic iron containing phases decreases continuously with increasing current density in all Fe-containing deposits. At the same time, no essential change in the magnetic anisotropy can be found with the plating time. 119Sn spectra reveal the presence of small amount of {beta}-Sn besides the main phases in Sn-Fe and in the Sn-Co coatings. Magnetically split 119Sn spectra reflecting transferred hyperfine field were observed in the case of Co-Sn-Fe coatings.

Influence of iron ions on the structural properties of some inorganic glasses

International Nuclear Information System (INIS)

Music, S.; Gotic, M.; Popovic, S.; Grzeta, B.

1987-01-01

The effects of iron on the structural properties of Zn-borosilicate glass and Pb-metaphosphate glass were studied using x-ray diffraction, 57 Fe Moessbauer spectroscopy and IR spectroscopy. At high concentration of iron the crystallization of zinc ferrite in the glass matrix takes place. X-ray diffraction and 57 Fe Moessbauer spectroscopy showed that the amount of zinc ferrite in Zn-borosilicate glass decreases. In Pb-metaphosphate glass doped with high concentration of α-Fe 2 O 3 , the crystallization of Fe 3 (PO 4 ) 2 is pronounced. The assignments of IR band positions and the corresponding interpretation are given. The importance of this study for the technology of vitrification of high-level radioactive wastes is emphasized. (author) 31 refs.; 6 figs,.; 6 tabs

Structural properties and hyperfine characterization of Sn-substituted goethites

Energy Technology Data Exchange (ETDEWEB)

Larralde, A.L. [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Ramos, C.P. [Departamento de Fisica de la Materia Condensada, GIyA - CAC - CNEA, Av. Gral. Paz 1499 (1650), San Martin, Bs. As. (Argentina); Arcondo, B. [Departamento de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Av. Paseo Colon 850 (C1063ACV), Bs. As. (Argentina); Tufo, A.E. [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Saragovi, C. [Departamento de Fisica de la Materia Condensada, GIyA - CAC - CNEA, Av. Gral. Paz 1499 (1650), San Martin, Bs. As. (Argentina); Sileo, E.E., E-mail: sileo@qi.fcen.uba.ar [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina)

2012-04-16

Highlights: Black-Right-Pointing-Pointer Pure and tin-doped goethites were synthesized from Sn(II) solutions at ambient pressure and 70 Degree-Sign C. Black-Right-Pointing-Pointer The Rietveld refinement of PXRD data indicated that Sn partially substituted the Fe(III) ions. Black-Right-Pointing-Pointer The substitution provoked unit cell expansion, and a distortion of the coordination polyhedron. Black-Right-Pointing-Pointer {sup 119}Sn Moessbauer spectroscopy revealed that Sn(II) is incorporated as Sn(IV). Black-Right-Pointing-Pointer {sup 57}Fe Moessbauer spectroscopy showed a lower magnetic coupling as tin concentration increased. - Abstract: Tin-doped goethites obtained by a simple method at ambient pressure and 70 Degree-Sign C were characterized by inductively coupled plasma atomic emission spectrometry, scanning electron microscopy, Rietveld refinement of powder X-ray diffraction data, and {sup 57}Fe and {sup 119}Sn Moessbauer spectroscopy. The particles size and the length to width ratios decreased with tin-doping. Sn partially substituted the Fe(III) ions provoking unit cell expansion and increasing the crystallinity of the particles with enlarged domains that grow in the perpendicular and parallel directions to the anisotropic broadening (1 1 1) axis. Intermetallic E, E Prime and DC distances also change although the variations are not monotonous, indicating different variations in the coordination polyhedron. In general, the Sn-substituted samples present larger intermetallic distances than pure goethite, and the greatest change is shown in the E Prime distance which coincides with the c-parameter. {sup 119}Sn Moessbauer spectroscopy revealed that Sn(II) is incorporated as Sn(IV) in the samples. On the other hand, Fe(II) presence was not detected by {sup 57}Fe Moessbauer spectroscopy, suggesting the existence of vacancies in the Sn-doped samples. A lower magnetic coupling is also evidenced from the average magnetic hyperfine field values obtained as tin

Anomaly observed in Moessbauer spectra near the neel temperature of FeBr sub 2

CERN Document Server

Naili Di

2003-01-01

In several decades, iron(II) bromide (FeBr sub 2) has been investigated as a typical Ising-type antiferromagnet by several kinds of experimental techniques. By the Moessbauer measurements, it was normally observed that only the magnetic spectrum appeared just below Neel temperature in FeBr sub 2. However, we found the anomalous spectra, in which paramagnetic component coexisted with magnetic one near Neel temperature. For two kinds of single crystal FeBr sub 2 samples, IM and IIM, we determined the Moessbauer parameters of the observed spectra by the computer analyses: the relative absorption intensity I sub p of the paramagnetic component to the total absorption area of the best fitting spectrum and the value of the hyperfine field H sub h sub f of the magnetic component and values of the quadrupole splitting 1/2 centre dot e sup 2 qQ of the magnetic and the paramagnetic components. The temperature variation of H sub h sub f is unique and the same as that observed for the sample in which the anomaly was not ...

First-order phase transitions in CaFe2As2 single crystal: a local probe study

International Nuclear Information System (INIS)

Alzamora, M; Munevar, J; Baggio-Saitovitch, E; Bud'ko, S L; Ni Ni; Canfield, P C; Sanchez, D R

2011-01-01

57 Fe Moessbauer spectroscopy has been used to investigate the structural and magnetic phase transitions of CaFe 2 As 2 (T N = 173 K) single crystals. For this compound we found that V ZZ is positive and parallel to the c-axis of the tetragonal structure. For CaFe 2 As 2 a magnetic hyperfine field B hf was observed at the 57 Fe nucleus below T N ∼ 173 K. Analysis of the temperature dependence of B hf data using the Bean-Rodbell model shows that the Fe spins undergo a first-order magnetic transition at ∼ 173 K. A collinear antiferromagnetic structure is established below this temperature with the Fe spin lying in the (a, b) plane. Below T N the paramagnetic fraction of Fe decreases down to 150 K and for lower temperatures all the Fe spins are magnetically ordered.

Phase analysis of the system La1-xBaxFeO3-y (0≤x≤0.70) by means of X-ray diffraction and Moessbauer spectroscopy

International Nuclear Information System (INIS)

Li, J.; Jing, J.

1992-01-01

X-ray diffraction and Moessbauer measurements were performed on novelly synthesized La 1-x Ba x FeO 3-y (0≤x≤0.70). Two phases were found in the system. La 1-x Ba x FeO 3-y for 0≤x≤0.10 is an orthorhombic perovskite. La 1-x Ba x FeO 3-y for 0.54≤x≤0.70 is a cubic perovskite. La 1-x Ba x FeO 3-y for 0.10≤x≤0.54 consists of these two phases. (orig.)

A Moessbauer study of doped magnetite

International Nuclear Information System (INIS)

Nistor, C.I.; Boekema, C.; Woude, F. van der; Sawatzky, G.A.

1975-01-01

Doped magnetite was investigated by means of the Moessbauer effect to ascertain the behaviour of conduction electrons in magnetite. The Moessbauer spectrum of Fe 3 O 4 recorded at room temperature consisted of two patterns: one corresponding to the Fe 3+ (A) ions and another corresponding to the Fe(B) ions. The first A and B lines of the room temperature Moessbauer spectra of Msub(0.1)Fesub(2.9)O 4 with M = Li, Ni and Sn are presented. The B site lines of the spectra were asymmetrically broadened and showed a certain structure whereas the A site lines were narrow. In the Moessbauer spectrum of Lisub(0.2)Fesub(2.8)O 4 recorded at 407 0 C even separate lines between the A and B patterns were observed. It was found that the symmetry and line broadening were only slightly temperature dependent and were still present at higher temperatures. The application of a charge oscillation model was found to be valid only for lower impurity concentrations. The Moessbauer study of doped magnetite revealed the occurrence of spin and charge density oscillations in the B sublattice. (Z.S.)

Electrodeposition of carrier-free 57Co on rhodium as an approach to the preparation of Moessbauer sources

International Nuclear Information System (INIS)

Cieszykowska, Izabela; ZoLtowska, MaLgorzata; Mielcarski, MieczysLaw

2011-01-01

Electrodeposition of carrier-free 57 Co on a rhodium matrix as the first step of preparing Moessbauer sources was studied. To optimize the plating parameters, the influences of current density, volume and pH of the electrolyte solution, shape, thickness, and surface area of the rhodium cathode, mode of cathode pretreatment, concentration of 57 Co and duration of electrolysis were investigated.

Investigation of iron-containing complexes of deoxyribonucleic acid nucleosides by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Greguskova, M.; Novotny, J.; Cernohorsky, I.; Cirak, J.

1975-01-01

DNA and nucleoside complexes with ferric and ferrous ions were investigated for the concentration of iron ions, ionic strength, temperature, and the nature and spatial configuration of neighbouring atoms of the iron ions in the complexes. Moessbauer spectroscopy was used. The Moessbauer measurements were conducted on lyophilized samples at room temperature (300 K) and on frozen solutions at liquid nitrogen temperature (77 K). Quadrupole splitting was found in all spectra obtained by a Pd(Co) source, with the exception of thymidine, thus indicating that the formation of complexes had not affected the oxidation state of iron ions. A decrease in isomer shift and an increase in quadrupole splitting were found in all spectra obtained by an iron(III) chloride source as well as in all spectra obtained by an iron chloride tetrahydrate source. UV irradiation of the samples prior to the Moessbauer measurements was found to have no effect on the Moessbauer spectra but to result in changes in the oxidation state of iron ions, mainly their valency and the ferrous/ferric ion ratio. The results are shown in a table and in graphs. (L.O.)

Synthesis and properties of iridium-doped hematite ({alpha}-Fe{sub 2}O{sub 3})

Energy Technology Data Exchange (ETDEWEB)

Krehula, Stjepko, E-mail: krehul@irb.hr [Division of Materials Chemistry, Ruder Boskovic Institute, P.O. Box 180, HR-10002 Zagreb (Croatia); Stefanic, Goran [Division of Materials Chemistry, Ruder Boskovic Institute, P.O. Box 180, HR-10002 Zagreb (Croatia); Zadro, Kreso [Department of Physics, Faculty of Science, University of Zagreb, Bijenicka 32, 10000 Zagreb (Croatia); Kratofil Krehula, Ljerka [Faculty of Chemical Engineering and Technology, University of Zagreb, Marulicev trg 19, 10000 Zagreb (Croatia); Marcius, Marijan; Music, Svetozar [Division of Materials Chemistry, Ruder Boskovic Institute, P.O. Box 180, HR-10002 Zagreb (Croatia)

2012-12-25

Highlights: Black-Right-Pointing-Pointer Ir-doped hematites were prepared by heating Ir-doped goethites. Black-Right-Pointing-Pointer Ir-doping in hematite led to an increase in unit cell and a decrease in crystallite size. Black-Right-Pointing-Pointer Ir-doping significantly affected magnetic, infrared and UV-Vis properties of hematite. Black-Right-Pointing-Pointer The Morin transition temperature increased with an increase in Ir-doping. Black-Right-Pointing-Pointer Ir ions brought about changes in the size and shape of the formed hematite particles. - Abstract: The effect of the incorporation of Ir{sup 3+} ions on the properties of {alpha}-Fe{sub 2}O{sub 3} formed by dehydroxylation of {alpha}-FeOOH was investigated using X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), {sup 57}Fe Moessbauer, UV-Vis-NIR and FT-IR spectroscopies, SQUID magnetometer, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Pure and Ir-doped hematite samples were obtained by heating of pure and Ir-doped goethites ({alpha}-FeOOH) formed by precipitation from mixed Fe(III)-Ir(III) chloride solutions in a highly alkaline medium. The incorporation of Ir{sup 3+} ions into the {alpha}-Fe{sub 2}O{sub 3} structure led to changes in unit-cell dimensions, crystallinity, particle size and shape, as well as changes in the magnetic, infrared and UV-Vis properties. An increase in the temperature of the Morin transition with an increase in Ir-doping was observed by Moessbauer spectroscopy and magnetic measurements.

Identification of crystalline structures using Moessbauer parameters and artificial neural network

International Nuclear Information System (INIS)

Salles, E.O.T.; Souza Junior, P.A. De; Garg, V.K.

1995-01-01

Moessbauer spectroscopy is a useful technique for characterizing the valences, electronic and magnetic states, coordination symmetric and site occupancies of Fe cations. The Moessbauer parameters of Isomer Shift (I.S.) and Quadrupole Splitting (Q.S.) are useful to distinguish paramagnetic ferrous and ferric ions in several substances, while the internal magnetic field provides information on the crystallinity. A correlation is being sought between Moessbauer parameters and several structure properties of some iron-containing minerals using Artificial Neural Networks (ANN). Distinct regions of crystalline structures are defined when any two parameters are plotted, but in several cases superposition of these regions leads to erroneous conclusions. We have tried to eliminate this difficulty by using convenient axes. These axes form n-dimensional vectors as input to our ANN. In recent years ANN has shown to be a powerful technique to solve problems as pattern recognition, optimization, preview ups and downs in stock market, automatic control and identification of a mineral from a Moessbauer spectrum of Moessbauer data bank. Using ANN we have been successful in identification of crystalline structures from plots of Moessbauer spectral parameters of I.S., Q.S., and structure using Moessbauer parameters of I.S., Q.S., and polyhedral volume of a coordination site are presented. (author) 28 refs.; 4 figs.; 2 tabs

On the photofragmentation of Fe(CO)5

International Nuclear Information System (INIS)

De Paoli, M.-A.; Oliveira, S.M. de; Saitovitch, E.M.B.; Guenzburger, D.J.R.

1983-01-01

Pentacarbonyliron sorbed in low density polyethylene (LDPE) or polytetrafluorethylene (PTFE) and irradiated with ultraviolet light has been studied by infrared and Moessbauer spectroscopies. The main photofragment reacts with the residual pentacarbonyliron leading to the formation of Fe 2 (CO) 9 . This reaction, plus the information obtained from infrared and Moessbauer spectra, suggest that the new species could be assigned as tetracarbonyliron, Fe(CO) 4 , and tricarbonyliron Fe(CO) 3 . It is proved that molecules sorbed in a polymer matrix can be used as Moessbauer absorbers at low temperature. The polymer matrix allowed the isolation of otherwise unstable species: the high permeability of LDPE to gaseous carbon monoxide precludes the reformation of pentacarbonyliron molecules, thus excluding the 'cage effect' observed in frozen gas matrices. (Author) [pt

Moessbauer study of isothermally annealed amorphous Fe-Nb-Cu-Si-B alloys

International Nuclear Information System (INIS)

Sitek, J.; Toth, I.; Miglierini, M.

1993-01-01

Amorphous ribbons of Fe 73.5 Nb 3 Cu 1 Si 13.5 B 9 have been annealed above the crystallization temperature. Annealed samples consisted of crystalline and amorphous phases in a wide temperature range. Two samples of different thicknesses of 33 μm and 27 μm were isothermally annealed at a temperature of 545 C from 0.5 to 5 h in a vacuum furnace. The amount of crystalline phase increases rapidly in the ticker sample. The crystalline part of the Moessbauer spectrum consists of four sharp sextets which can be assigned to a DO 3 -structure FeSi alloy. After 700 C annealing the amorphous phase was not observed and the crystalline phase consisted of the DO 3 -structure FeSi alloy, paramagnetic FeNbB and presumably Fe 23 B 6 and Fe 3 SiB 2 . (orig.)

Moessbauer and muon spin relaxation investigation of magnetic and superconducting properties of Ca{sub 1-x}Na{sub x}Fe{sub 2}As{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Materne, Philipp; Bubel, Sirko; Maeter, Hemke; Sarkar, Rajib; Klauss, Hans-Henning [Institut fuer Festkoerperphysik, Technische Universitaet Dresden, 01062 Dresden (Germany); Harnagea, Luminita; Wurmehl, Sabine; Buechner, Bernd [IFW Dresden, Postfach 270016, 01171 Dresden (Germany); Luetkens, Hubertus [Paul-Scherrer-Institut, 5232 Villigen (Switzerland)

2013-07-01

The antiferromagnetic parent compound, CaFe{sub 2}As{sub 2}, shows a supression of the spin density wave and a subsequent superconducting state upon partial substitution of Ca by Na. Along the substitution series, superconducting transition temperatures up to ∼35 K were found. We studied the electronic phase diagram of Ca{sub 1-x}Na{sub x}Fe{sub 2}As{sub 2} using Moessbauer spectroscopy and muon spin relaxation experiments. We have analyzed the data in terms of magnetic and superconducting properties and possible coexistence of superconductivity and spin density wave order. We compared our results with recently published data of Ba{sub 1-x}Na{sub x}Fe{sub 2}As{sub 2}.

Moessbauer spectroscopic evidence for iron(III) complexation and reduction in acidic aqueous solutions of indole-3-butyric acid

International Nuclear Information System (INIS)

Kovacs, K.; Kuzmann, E.; Vertes, A.; Kamnev, A.A.; Shchelochkov, A.G.; Medzihradszky-Schweiger, H.; Mink, J.; Hungarian Academy of Sciences, Budapest

2004-01-01

Moessbauer spectroscopic studies were carried out in acidic (pH 2.3) 57 Fe III nitrate containing aqueous solutions of indole-3-butyric acid (IBA), rapidly frozen in liquid nitrogen at various periods of time after mixing the reagents. The data obtained show that in solution in the presence of IBA, iron(III) forms a complex with a dimeric structure characterised by a quadrupole doublet, whereas without IBA under similar conditions iron(III) exhibits a broad spectral feature due to a slow paramagnetic spin relaxation which, at liquid nitrogen temperature, results in a large anomalous line broadening (or, at T = 4.2 K, in a hyperfine magnetic splitting). The spectra of 57 Fe III +IBA solutions, kept at ambient temperature under aerobic conditions for increasing periods of time before freezing, contained a gradually increasing contribution of a component with a higher quadrupole splitting. The Moessbauer parameters for that component are typical for iron(II) aquo complexes, thus showing that under these conditions gradual reduction of iron(III) occurs, so that the majority (85%) of dissolved iron(III) is reduced within 2 days. The Moessbauer parameters for the iron(III)-IBA complex in aqueous solution and in the solid state (separated from the solution by filtration) were found to be similar, which may indicate that the dissolved and solid complexes have the same composition and/or iron(III) coordination environment. For the solid complex, the data of elemental analysis suggest the following composition of the dimer: [L 2 Fe-(OH) 2 -FeL 2 ] (where L is indole-3-butyrate). This structure is also in agreement with the data of infrared spectroscopic study of the complex reported earlier, with the side-chain carboxylic group in indole-3-butyrate as a bidentate ligand. The Moessbauer parameters for the solid 57 Fe III -IBA complex at T = 80 K and its acetone solution rapidly frozen in liquid nitrogen were virtually identical, which indicates that the complex retains its

Aging effect in CaLaBa{l_brace}Cu{sub 1 - x}Fe{sub x}{r_brace}{sub 3}O{sub 7 - {delta}} with 0 {<=} x {<=} 0.07 studied by Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Bustamante, Angel, E-mail: angelbd1@gmail.com [Universidad Nacional Mayor de San Marcos, Laboratorio de Ceramicos y Nanomateriales, Facultad de Ciencias Fisicas (Peru); Santos Valladares, Luis De Los, E-mail: ld301@cam.ac.uk [University of Cambridge, Cavendish Laboratory (United Kingdom); Flores, Jesus [Universidad Nacional Mayor de San Marcos, Laboratorio de Ceramicos y Nanomateriales, Facultad de Ciencias Fisicas (Peru); Barnes, Crispin H. W. [University of Cambridge, Cavendish Laboratory (United Kingdom); Majima, Yutaka [Tokyo Institute of Technology, Materials and Structures Laboratory (Japan)

2011-11-15

In this work, we study the long-term aging effect caused by Fe atoms in the superconductor CaLaBa{l_brace}Cu{sub 1 - x}Fe{sub x}{r_brace}{sub 3}O{sub 7 - {delta}} with 0 {<=} x {<=} 0.07. XRD confirms that this system has a YBCO-like structure. The critical temperature (T{sub c}) is strongly affected by aging and depends on the amount of Fe in the structure. Room temperature Moessbauer spectroscopy reveals the presence of the typical species A, B-B Prime , C and new species E Prime and F. Interestingly; A, which corresponds to the Fe{sup 3 + } atom located in the Cu(1) of the chains with spin S{sub z} = 3/2, shows a drastic reduction which means migration to the species B, B Prime and C. Species B and B Prime correspond to the Fe{sup 3 + } in the Cu(2) site forming planar quasi-octahedral and planar square pyramidal, while the C specie is a square pyramidal with O(5) respectively (spin S{sub z} = 3/2 in all these cases). Aging causes loss of superconductivity in the samples with 5 and 7% of iron content.

A Moessbauer study on the photolysis of potassium trisoxalatoferrate(III) in solid and solutions

International Nuclear Information System (INIS)

Sato, H.; Tominaga, T.

1977-01-01

The photolysis of potassium trisoxalatoferrate(III) in solid and aqueous solutions was studied by Moessbauer spectroscopy. A ferrous species was mainly detected as an intermediate product in the photoirradiated solutions. A tentative mechanism was proposed for the overall reactions in and after the photolysis of this compound. The Moessbauer spectra were measured with a Hitachi AA-40 or Shimadzu MEG-2 Moessbauer spectrometer against Co-57 in copper foil. Acrylic holders (32 mm in diameter) were used for measurements of solutions: the irradiated solution was quickly frozen before measurement by adding it dropwise into the acrylic holder which had been cooled with liquid nitrogen or dry-ice. (T.I.)

Moessbauer and X-ray Study of Fe1-xAlx, 0.2≤x≤0.5, Samples Produced by Mechanical Alloying

International Nuclear Information System (INIS)

Oyola Lozano, D.; MartInez, Y. Rojas; Bustos, H.; Perez Alcazar, G. A.

2004-01-01

In this work we report the magnetic and structural properties obtained by Moessbauer spectroscopy and X-ray diffraction, of the Fe 1-x Al x , 0.2≤x≤0.5, alloys produced by mechanical alloying. Alloys with x=0.2, 0.3, 0.4 and 0.5, were for milled 12, 24, 36, and 48 hours. All the obtained alloys are in the bcc phase. The obtained Moessbauer spectra are characteristic of disordered ferromagnetic system. The lattice parameter remains nearly constant (∼2.91 A) for all the milling times and compositions. The mean grain sizes in the (110) and (211) direction are nearly constants with the milling time but vary from 15.5 to 11 nm and from 10.5 to 8.5 nm when Al content grow between x=0.2 to x=0.4, respectively. The difference between the mean grain sizes in these two directions shows that the grains are of prolate spheroid form.

Using Moessbauer spectroscopy as key technique in the investigation of nanosized magnetic particles for drug delivery

Energy Technology Data Exchange (ETDEWEB)

Morais, P. C., E-mail: pcmor@unb.br [Universidade de Brasilia, Nucleo de Fisica Aplicada, Instituto de Fisica (Brazil)

2008-01-15

This paper describes how cobalt ferrite nanoparticles, suspended as ionic or biocompatible magnetic fluids, can be used as a platform to built complex nanosized magnetic materials, more specifically magnetic drug delivery systems. In particular, the paper is addressed to the discussion of the use of the Moessbauer spectroscopy as an extremely useful technique in supporting the investigation of key aspects related to the properties of the hosted magnetic nanosized particle. Example of the use of the Moessbauer spectroscopy in accessing information regarding the nanoparticle modification due to the empirical process which provides long term chemical stability is included in the paper.

Moessbauer study of iron-sugar complexes

International Nuclear Information System (INIS)

Tonkovic, M.; Music, S.; Hadzija, O.; Nagy-Czako, I.; Vertes, A.

1982-01-01

Ferric-fructose complex has been prepared using FeCl 3 and Fe(NO 3 ) 3 solutions. Molecular weight determination and Moessbauer spectroscopic measurements proved that the ferric-fructose complex is polymeric in solid state and also in aqueous solution. The synthesis of a new iron-sorbose complex has been performed. Its Moessbauer spectra indicate a structure similar to that of the iron-fructose complex. (author)

The Role of Intermediates in the Process of Red Ferric Pigment Manufacture from FeSO4.7H2O

International Nuclear Information System (INIS)

Zboril, Radek; Mashlan, Miroslav; Petridis, Dimitris; Krausova, Dagmar; Pikal, Petr

2002-01-01

One method of industrial manufacture of red ferric pigments is based on the thermal decomposition of FeSO 4 .7H 2 O into α-Fe 2 O 3 (copperas red). The difficult reproducibility of the color quality of the final pigment is the main problem of this process. One of the factors that can influence the pigment color is contamination by some of the intermediates formed during the transformation process. The identification of two groups of intermediates is the basic result of an extensive laboratory investigation carried out using 57 Fe Moessbauer spectroscopy and X-ray powder diffraction (XRD). The first group of intermediates includes sulfato-phases as FeSO 4 .H 2 O, FeSO 4 , Fe(OH)SO 4 , Fe 2 O(SO 4 ) 2 , Fe 2 O(SO 4 ) 2 .xH 2 O x element of (0,1), and Fe 2 (SO 4 ) 3 . Thermally metastable polymorphs of iron(III) oxide, β-Fe 2 O 3 , γ-Fe 2 O 3 and ε-Fe 2 O 3 , represent the other group. Moessbauer characterization of all intermediate products is given. A significant influence of β-Fe 2 O 3 on the pigment color was found.

Contribution of back-scattered electromagnetic rays to the Moessbauer conversion electron spectrum

International Nuclear Information System (INIS)

Ruskov, T.; Ruskov, R.; Paneva, D.; Lefterov, D.

1999-01-01

The contribution of back-scattered electromagnetic rays in a 57 Fe conversion electron Moessbauer spectrum is considered using proportional counter as a detector. A simplified method for measuring this contribution is described. The experimental results show that this contribution strongly depends on the construction of the counter and the selected fraction in the pulse-height spectrum

A CEMS study of surface oxidation of Fe-Ni alloys

International Nuclear Information System (INIS)

Cruz, B.; Tabares, J.A.; Bohorquez, A.; Perez Alcazar, G.A.

1997-01-01

A study by conversion electron Moessbauer spectroscopy (CEMS) carried out by using a parallel plate avalanche counter with samples of Fe-Ni alloys (50 and 65 at.% Fe) is reported. Each sample was analyzed without oxidation and after heating it under an oxygen atmosphere at 200 C. All CEMS measurements were carried out at room temperature. In both samples (50 and 65 at.% Fe), without oxidation and after oxidation, the Moessbauer spectra showed a six line magnetic spectrum according to their ferromagnetic character, with a broad hyperfine field distribution (HFD), according to the disordered character of the alloys. The obtained mean hyperfine field (MHF) for the sample 50 at.% Fe was 30.9 T, meanwhile for the invar composition (65 at.% Fe) was 25.5 T, which is close to values previously reported by transmission Moessbauer spectroscopy (TMS). Results from the treated samples (with oxidation at 200 C) showed a difference in the surface composition as a result of this process. In the 50 at.% Fe sample, additionally appeared a double that could be assigned to an oxihydroxide of Fe 3+ . Otherwise, the 65 at.% Fe sample (invar) presented ferromagnetic oxides (α-Fe 2 O 3 and Fe 3 O 4 ) with a large relative area (82.5%). (orig.)

Development of system and technology for moessbauer spectroscopic microscope

Energy Technology Data Exchange (ETDEWEB)

Hayakawa, Kazuo; Akiyama, Yuki; Tsukamoto, Yoshinori; Kurata, Mikio; Yukihira, Kenichi [Shizuoka Institute of Science and Technology (Japan); Soejima, Hiroyoshi [Shimadzu Corporation (Japan); Yoshida, Yutaka, E-mail: yoshida@ms.sist.ac.jp [Shizuoka Institute of Science and Technology (Japan)

2012-03-15

We have been developing a 'Moessbauer Spectroscopic Microscope (MSM)' which consists of a focusing lens for 14.4 keV {gamma}-rays and a high precision X-Y stage. The measuring system both for electrons and {gamma}-rays combined with a new Moessbauer driver, i.e., 'a moving coil actuator with a liner encoder' enables us to measure the mapping images simultaneously corresponding to different spectral components. The system has a controlling system based on a LabVIEW program and a LIST mode data acquisition system (NIKI-GLASS/A3100). To investigate a correlation between the microstructure of a sample and {sup 57}Fe atoms, a scanning electron microscope (APCO/Mini-EOC) is also installed to this system.

Moessbauer investigation of characteristic distribution of iron oxides in sediments from the Antarctica

International Nuclear Information System (INIS)

Kuzmann, E.; Homonnay, Z.; Vertes, A.; Garg, V.K.; De Oliveira, A.C.; De Souza Junior, P.A.; Schuch, L.A.

2000-01-01

Sediments from the Admirally Bay, King George Island, Antarctica, were investigated by 57 Fe Moessbauer spectroscopy, X-ray diffractometry, and radiometry. Quartz, feldspar, chlorite, calcite, dolomite, mica, kaolinite, hematite and magnetite were identified as constituent minerals in the sediment samples. The phase composition and the iron distribution among the crystallographic sites of iron-bearing minerals (silicates, magnetite and hematite) of samples from different location have been derived from the complex Moessbauer spectra. At different locations sediments has significant characteristic differences in the mineral composition, in the iron distribution among the crystallographic site of silicates, and in the specific radioactivity of Cs radionuclides. These results indicate differences in the rock formation and alteration by the sediments in this maritime part of Antarctica. There is a much higher amount of iron oxides in the sediments from south part of the geological fault across the Admirally Bay than in the north part. This can be associated with much more alteration in the rocks in the south part compared to the northern one. This finding can contribute to the question of the history of the formation and alteration of volcanic rocks in the border of Antarctica. (author)

Moessbauer study of CO-precipitated Fischer-Tropsch iron catalysts

International Nuclear Information System (INIS)

Rao, K.R.P.M.; Huggins, F.E.; Mahajan, V.; Huffman, G.P.; Bukur, D.B.; Rao, V.U.S.

1994-01-01

Moessbauer spectroscopy studies of precipitated Fischer-Tropsch (FT) iron catalysts, viz. 100 Fe/5 Cu/4.2 K/x SiO 2 , where x = 0, 8, 16, 24, 25, 40, or 100, have shown that reduction of the oxide precursor in CO gives rise to χ-carbide Fe 5 C 2 whose amount decreases with an increase of SiO 2 content. The χ-carbide is converted into magnetite Fe 3 O 4 while catalyzing the FT synthesis reaction. A correlation between FT activity and the content of χ-carbide in the catalysts was found, which indicated that χ-carbide is active for FT synthesis reaction. (orig.)

Investigation into iron moessbauer atom state in a deformed iron-manganese alloys

International Nuclear Information System (INIS)

Mints, R.I.; Semenkin, V.A.; Shevchenko, Yu.A.

1977-01-01

A plastically deformed Fe + 12 at. %. Mn alloy was investigated by the method of nuclear gamma-resonance on Fe 57 nuclei. The specimens were deformed by 5 to 57 %. The obtained nuclear gamma-resonance spectra, which are a superposition of the paramagnetic single line (ν-phase) and the Zeeman splitting line (α-phase), were statistically processed with the aid of a computer. The behaviour of the values of Moessbauer parameters possessing a least dispersion, such as isomer chemical shift, quadrupolar reaction constant, effectiveness of magnetic field and of area of the nuclear gamma-resonance spectrum, points to their connection with the degree of the deformation disintegration of the initial solid solution

Study of iron-zinc catalysts by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Arriola, S.H.

1990-01-01

The Moessbauer parameters were determined on a series of catalyst mixtures of iron and zinc oxides with variable quantities of zinc. A change in the crystal structure of the iron oxide when introducing zinc into the samples was observed. The corundum structure of the α-Fe 2 O 3 phase was transformed into the spinel type of zinc ferrite when zinc oxide was present in any quantity. A strong electronic interaction between the zinc ferrite and the zinc oxide present in excess was evident. The catalysts were analyzed using x-ray fluorescence and x-ray diffraction methods. (author) 10 refs.; 4 figs.; 2 tabs

Spin-wave excitation and Moessbauer spectrometry of amorphous interface in Tb/Fe multilayer

International Nuclear Information System (INIS)

El Khiraoui, S.; Sajieddine, M.; Lassri, H.; Sahlaoui, M.

2009-01-01

Magnetic properties of Tb(48 A)/Fe(26 A) multilayer were studied with Moessbauer spectrometry at different temperatures before and after isothermal annealing at 673 K. For this last case, a significant perpendicular magnetic anisotropy is induced. This phenomenon is related to the existence of an amorphous and homogenous Tb-Fe alloy, located at the interfaces, which is produced by interdiffusion during the heat processing. The thermal evolution of hyperfine field deduced for interfacial Tb-Fe alloy is found to obey the Bloch law. The spin-wave stiffness constant, the distance between nearest magnetic atoms and the exchange parameter A were calculated from the experimental results

Characterization of Egyptian coal from Sinai using Moessbauer spectroscopy

International Nuclear Information System (INIS)

Eissa, N.A.; Abdel Meguid, M.M.; Deriu, A.; Albanese, G.

1983-08-01

The presence of iron bearing minerals in coal makes the Moessbauer Spectroscopy (MS) extremely useful for characterization of coals from different localities. In this paper the MS has been applied to characterize Egyptian coal from Sinai (Maghara). The chemical analysis of this coal is given. The MS results showed that pyritic sulphur (pyrite and marcasite) is the only bearing mineral in Egyptian coal. A review is given for the iron bearing minerals in coals from different countries measured by MS. (author)

Moessbauer experiments, ch. 1

International Nuclear Information System (INIS)

Maring, K.W.

1977-01-01

The magnetic properties of iron base alloys have been investigated as a function of the concentrations of the sp-elements Al, Si, Ga, Ge, As, Sn, and Sb. An extensive description of the Moessbauer Effect Spectroscopy (MES) technique is given. The results of MES experiments at room temperature for FeX alloys (X stands for one of the sp-elements) and impurity concentrations of 1, 3 and 5 a/o are presented. Through temperature dependant measurements the hyperfine fields H ((m,n)T) at iron nuclei in different surroundings are obtained. The change of the Curie temperature of the various dilute iron-base alloys, with respect to pure iron, as a function of the impurity concentration is investigated. Average magnetic hyperfine fields and isomer shifts measured at 119 Sn nuclei in Fe 119 Sn are discussed

Moessbauer study of Haltern 70 amphora sherds from Castro do Vieito, North of Portugal

Energy Technology Data Exchange (ETDEWEB)

Costa, B F O; Ramos Silva, M [CEMDRX, Department of Physics, University of Coimbra, P-3004-516, Coimbra (Portugal); Pereira, G [Science Museum of the University of Coimbra, P-3000-272, Coimbra Portugal (Portugal); Silva, A J M [Centro de Estudos Arqueologicos das Universidades de Coimbra e do Porto/CAM, Palacio de Sub-Ripas P-3004-395 Coimbra (Portugal); Carmo, S J C do, E-mail: benilde@ci.uc.p [GIAN, Department of Physics, University of Coimbra, P-3004-516, Coimbra (Portugal)

2010-03-01

Haltern 70 amphora sherds obtained from Castro do Vieito were studied by Moessbauer spectroscopy, X-ray diffraction and X-ray fluorescence. In all our samples non magnetic Fe{sup 3+} haematite species were found. In some samples, also Fe{sup 2+} was found. We conclude that the samples were fired under changing atmosphere, air being admitted at the end of the firing cycle following firing in a reducing atmosphere.

Application of Moessbauer spectroscopy to the study of tannins inhibition of iron and steel corrosion

Energy Technology Data Exchange (ETDEWEB)

Jaen, Juan A., E-mail: jjaen@ancon.up.ac.pa [Universidad de Panama, CITEN, Depto. de Quimica Fisica (Panama); Obaldia, J. De; Rodriguez, M. V. [Universidad de Panama, Escuela de Quimica, Facultad de Ciencias Naturales, Exactas y Tecnologia (Panama)

2011-11-15

The inhibitory effect of tannins was investigated using, among others, potentiodynamic polarizations and Moessbauer spectroscopy. These techniques confirmed that the nature, pH and concentration of tannic solution are of upmost importance in the inhibitory properties of the solutions. It is observed that at low tannin concentration or pH, both, hydrolizable and condensed tannins, effectively inhibit iron corrosion, due to the redox properties of tannins. At pH Almost-Equal-To 0, Moessbauer spectra of the frozen aqueous solutions of iron(III) with the tannin solutions showed that iron is in the form of a monomeric species [Fe(H{sub 2}O){sub 6}]{sup 3 + }, without coordination with the functional hydroxyl groups of the tannins. The suspended material consisted of amorphous ferric oxide and oxyhydroxides, though with quebracho tannin partly resulted in complex formation and in an iron (II) species from a redox process. Other tannins, such as chestnut hydrolysable tannins, do not complex iron at this low pH. Tannins react at high concentrations or pH (3 and 5) to form insoluble blue-black amorphous complexes of mono-and bis-type tannate complexes, with a relative amount of the bis-ferric tannate generally increasing with pH. Some Fe{sup 2 + } in the form of hydrated polymeric ferrous tannate could be obtained. At pH 7, a partially hydrolyzed ferric tannate complex was also formed. The latter two phases do not provide corrosion protection. Tannin solutions at natural pH react with electrodeposited iron films (approx. 6 {mu}m) to obtain products consisting only on the catecholate mono-complex of ferric tannate. Some aspects of the mechanism of tannins protection against corrosion are discussed.

Moessbauer spectroscopic studies of alkylammonium iron(III) complexes

International Nuclear Information System (INIS)

Katada, M.; Kozawa, S.; Nakajima, Y.

2006-01-01

Alkylammonium iron(III) complexes, [(n-C n H 2n+1 )mNH 4-m ] 3 [Fe(CN) 6 ] were prepared and studied by Moessbauer spectroscopy, XRD, and DSC. In the complexes with m=2, the temperature dependences of the area intensity of Moessbauer are correlated to the motion of alkyl chains. The temperature dependence of the complex with n=4 was linear and smaller than that of other complexes. Especially in the complex with n=6, the deviation from the linear was the largest in the complexes observed. This result is attributed to the structural difference of the complex. The complexes with n≥8 consist of two-dimensional layer structure. The temperature dependence of the area intensity was similar to each other. This means that the motion of alkyl chain in these complexes are almost the same. The values of quadrupole splitting for the complexes were larger those that of the complexes (m=1). This indicates that the form of [Fe(CN) 6 ] 3- ion is affected by the differences of the number of alkyl groups. (author)

Moessbauer study of isothermally annealed amorphous Fe-Nb-Cu-Si-B alloys

Energy Technology Data Exchange (ETDEWEB)

Sitek, J. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia)); Toth, I. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia)); Miglierini, M. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia))

1993-11-01

Amorphous ribbons of Fe[sub 73.5]Nb[sub 3]Cu[sub 1]Si[sub 13.5]B[sub 9] have been annealed above the crystallization temperature. Annealed samples consisted of crystalline and amorphous phases in a wide temperature range. Two samples of different thicknesses of 33 [mu]m and 27 [mu]m were isothermally annealed at a temperature of 545 C from 0.5 to 5 h in a vacuum furnace. The amount of crystalline phase increases rapidly in the ticker sample. The crystalline part of the Moessbauer spectrum consists of four sharp sextets which can be assigned to a DO[sub 3]-structure FeSi alloy. After 700 C annealing the amorphous phase was not observed and the crystalline phase consisted of the DO[sub 3]-structure FeSi alloy, paramagnetic FeNbB and presumably Fe[sub 23]B[sub 6] and Fe[sub 3]SiB[sub 2]. (orig.)

Moessbauer studies of Inca ceramics

International Nuclear Information System (INIS)

Wagner, U.; Wagner, F.E.; Marticorena, B.; Salazar, R.; Schwabe, R.; Riederer, J.

1986-01-01

To obtain information on the firing of Inca ceramics, 7 samples from different locations were studied by Moessbauer spectroscopy including a detailed laboratory refiring procedure. The glaze typical for the surface of this ware was studied by Moessbauer scattering. (Auth.)

The Moessbauer effect used to study iron minerals in Brazil

International Nuclear Information System (INIS)

Kunrath, J.I.

1975-01-01

The Moessbauer effect in Fe 57 was used to study iron minerals in Brazil. More than 50 samples were analyzed in this preliminary work. Although many minerals present complex spectra, it was possible to find a number of samples with relatively pure natural materials, which may be considered representative of the simple compounds that enter as constituents in the more complex cases. Important and, in some cases, drastic differences were found between spectra at room and liquid nitrogen temperatures. These differences are reported and in some cases explained. Another feature was the difference in the Moessbauer effect spectra, observable when some crystallization water is present. This phenomenon is correlated to the previous one. The methodology of this study is also reported [pt

Moessbauer and transport studies of amorphous and icosahedral Zr-Ni-Cu-Ag-Al alloys

International Nuclear Information System (INIS)

Stadnik, Z.M.; Rapp, O.; Srinivas, V.; Saida, J.; Inoue, A.

2002-01-01

The alloy Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 in the amorphous and icosahedral states, and the bulk amorphous alloy Zr 65 Al 7.5 Ni 10 Cu 7.5 Ag 10 , have been studied with 57 Fe Moessbauer spectroscopy, electrical resistance and magnetoresistance techniques. The average quadrupole splitting in both alloys decreases with temperature as T 3/2 . The average quadrupole splitting in the icosahedral alloy is the largest ever reported for a metallic system. The lattice vibrations of the Fe atoms in the amorphous and icosahedral alloys are well described by a simple Debye model, with the characteristic Moessbauer temperatures of 379(29) and 439(28) K, respectively. Amorphous alloys Zr 65 Al 7. )5Ni 10 Cu 7.5 Ag 10 and Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 have been found to be superconducting with the transition temperature, T c , of about 1.7 K. The magnitude of Tc and the critical field slope at Tc are in agreement with previous work on Zr-based amorphous superconductors, while the low-temperature normal state resistivity is larger than typical results for binary and ternary Zr-based alloys. The resistivity of icosahedral Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 is larger than that for the amorphous ribbon of the same composition, as inferred both from direct measurements on the ribbons and from the observed magnetoresistance. However the icosahedral sample is non-superconducting in the measurement range down to 1.5 K. The results for the resistivity and the superconducting T c both suggest a stronger electronic disorder in the icosahedral phase than in the amorphous phase. (author)

Spin structure of exchange biased heterostructures. Fe/MnF{sub 2} and Fe/FeF{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Sahoo, B

2006-12-18

In this work, the {sup 57}Fe probe layer technique is used in order to investigate the depth- and temperature-dependent Fe-layer spin structure of exchange biased Fe/MnF{sub 2} and Fe/FeF{sub 2} (pseudo-twinned) antiferromagnetic (AFM) systems by conversion electron Moessbauer spectroscopy (CEMS) and nuclear resonant scattering (NRS) of synchrotron radiation. Two kinds of samples with a 10 A {sup 57}Fe probe layer directly at or 35 A away from the interface, labeled as interface and center sample, respectively, were studied in this work. The results obtained by CEMS for Fe/MnF{sub 2} suggests that, at 80 K, i.e., above T{sub N}=67 K of MnF{sub 2}, the remanent state Fe-layer spin structure of the two studied samples are slightly different due to their different microstructure. In the temperature range from 300 K to 80 K, the Fe-layer spin structure does not change just by zero-field cooling the sample in remanence. For Fe/FeF{sub 2}, a continuous non-monotonic change of the remanent-state Fe spin structure was observed by cooling from 300 K to 18 K. NRS of synchrotron radiation was used to investigate the temperature- and depth-dependent Fe-layer spin structure during magnetization reversal in pseudo-twinned Fe/MnF{sub 2}. A depthdependent Fe spin structure in an applied magnetic field (applied along the bisector of the twin domains) was observed at 10 K, where the Fe spins closer to the interface are not aligned along the field direction. The depth-dependence disappears at 150 K. (orig.)

Identification of Spinel Iron Oxide Nanoparticles by 57Fe NMR

Directory of Open Access Journals (Sweden)

SangGap Lee

2011-12-01

Full Text Available We have synthesized and studied monodisperse iron oxide nanoparticles of smaller than 10 nm to identify between the two spinel phases, magnetite and maghemite. It is shown that 57Fe NMR spectroscopy is a promising tool for distinguishing between the two phases.

Moessbauer study of iron diffusion in beryllium

International Nuclear Information System (INIS)

Sepiol, B.; Ruebenbauer, K.; Miczko, B.; Birchall, T.

1991-01-01

The broadening of the 14.41 keV Moessbauer line of 57 Fe dure to diffusion of iron atoms in polycrystalline beryllium has been investigated in the temperature range 1123 to 1423 K. The observed broadenings obey the Arrhenius law with activation energy 1.66(10) eV, i.e., lower than that obtained from the corresponding polycrystalline tracer data. The variations of the resonant fraction, second order Doppler shift and quadrupole splitting versus temperature are reported. An average diffusion coefficient has been calculated from the obtained broadenings and compared with the tracer results. (orig.)

Amorphous substances: contribution of Moessbauer spectrometry. Pt. 6. Studies of amorphous metallic alloys and amorphous semiconductors using Moessbauer spectrometry

International Nuclear Information System (INIS)

Le Caer, G.; Dubois, J.M.

1980-01-01

The sensitivity of Moessbauer spectrometry to the immediate environment of the nucleus is both an advantage and a disadvantage, because all the hyperfine parameters can be a priori distributed. The information related to these distributions (example local chemical order) depends on the hypotheses necessary for calculating the spectra. These hypotheses do not however seriously affect information on the texture or magnetic structure obtainable from the line intensities. These hypotheses are presented together with their consequences, an illustration being given for the case of the 57 Fe isotope. Some typical applications are then given [fr

Bonding and Moessbauer Isomer Shifts in （Hg,Pb）—1223 Cuprate

Institute of Scientific and Technical Information of China (English)

高发明; 田永君; 谌岩; 李东春; 董海峰; 张思远

2003-01-01

By using the chemical bond theory of dielectric description,the chemical bond parameters of(Hg,Pb)-1223 were calculated.The results show that the(Ba,Sr)-O and Ca-0 types of bond have higher ionic character,while the Cu-O and(Hg,Pb)-0 types of bond have more covalent character.Moessbauer isomer shifts of 57Fe and 119Sn doped in(Hg,Pb)-1223 were calculated by using the chemical environmental factor,he,defined by covalency and electronic polarizability.Four valence state tin and three valence iron sites were identified in 57Fe and 119Sn doped(Hg,Pb)-1223 superconductor.It can be concluded that all of the Fe atoms substitute the Cu at square planar Cu(1) site,Whereas Sn prefers to substitute the square pyramidal Cu(2) site.

Moessbauer and X-ray Study of Fe{sub 1-x}Al{sub x}, 0.2{<=}x{<=}0.5, Samples Produced by Mechanical Alloying

Energy Technology Data Exchange (ETDEWEB)

Oyola Lozano, D., E-mail: doyola@ut.edu.co; MartInez, Y. Rojas; Bustos, H.; Perez Alcazar, G. A. [Universidad del Tolima, Departamento de Fisica (Colombia)

2004-12-15

In this work we report the magnetic and structural properties obtained by Moessbauer spectroscopy and X-ray diffraction, of the Fe{sub 1-x}Al{sub x}, 0.2{<=}x{<=}0.5, alloys produced by mechanical alloying. Alloys with x=0.2, 0.3, 0.4 and 0.5, were for milled 12, 24, 36, and 48 hours. All the obtained alloys are in the bcc phase. The obtained Moessbauer spectra are characteristic of disordered ferromagnetic system. The lattice parameter remains nearly constant ({approx}2.91 A) for all the milling times and compositions. The mean grain sizes in the (110) and (211) direction are nearly constants with the milling time but vary from 15.5 to 11 nm and from 10.5 to 8.5 nm when Al content grow between x=0.2 to x=0.4, respectively. The difference between the mean grain sizes in these two directions shows that the grains are of prolate spheroid form.

A Moessbauer study of hemoglobin in paroxysmal nocturnal hemoglobinuria

International Nuclear Information System (INIS)

Zamorano-Ulloa, R.; Yee-Madeira, H.; Flores-Llamas, H.; Perez-Ramirez, J.G.

1991-01-01

The 57 Fe Moessbauer spectra of concentrated hemoglobin (Hb) of normal subjects and six patients with Paroxysmal Nocturnal Hemoglobinuria (PNH) were studied at 300deg K and 77 K. PNH is a very rate autoimmune hematological disease. The possibility of structural alterations of Hb induced by, or as part of the altered PNH-red cell membrane was the objective of this study. The Moessbauer parameters of the Hb of the normal subjects, both at 300 K and at 77 K, are identical to values previously reported. The PNH-Hb spectra show clear differences. They are wider and more asymmetric. At 77 K, an extra doublet grows in with an isomer shift of 0.425 mm/sec. and a quadrupolar splitting of 1.951 mm/sec. The other two doublets have δ's and ΔQ's slightly, but significantly, different from the corresponding values for normal Hb. These results are rationalized in terms of a population of Hb molecules with structures varying very slightly in a narrow range. The spread in structures manifests itself in a wider and more asymmetric Moessbauer spectrum. (orig.)

Moessbauer spectroscopic studies of hemoglobin and its isolated subunits