The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
V A Semionkin - One of the best experts on this subject based on the ideXlab platform.
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characterization of northwest africa 6286 and 7857 ordinary chondrites using x ray diffraction magnetization measurements and Mossbauer Spectroscopy
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2018Co-Authors: A A Maksimova, M I Oshtrakh, A V Chukin, I Felner, Grigoriy A Yakovlev, V A SemionkinAbstract:Northwest Africa (NWA) 6286 and 7857 meteorites were studied in detail by using optical microscopy, scanning electron microscopy with energy dispersion Spectroscopy, X-ray diffraction, magnetization measurements and 57Fe Mossbauer Spectroscopy with a high velocity resolution. The main and the minor iron-bearing phases were identified in both meteorites. The unit cell parameters as well as Fe2+ and Mg2+ cation distribution were determined for the M1 and M2 sites in silicate microcrystals. Saturation magnetic moments were obtained for both meteorites. Mossbauer parameters for the main and the minor iron-bearing microcrystals were estimated and compared for NWA 6286 and NWA 7857 LL6 ordinary chondrites. The Fe2+ and Mg2+ cation partitioning, distribution coefficient and temperature of cation equilibrium distribution were estimated for silicate microcrystals using X-ray diffraction and Mossbauer Spectroscopy.
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57fe Mossbauer Spectroscopy and electron paramagnetic resonance studies of human liver ferritin ferrum lek and maltofer
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014Co-Authors: I V Alenkina, M I Oshtrakh, A V Chukin, E Kuzmann, Zoltan Klencsar, V A SemionkinAbstract:Abstract A human liver ferritin, commercial Ferrum Lek and Maltofer® samples were studied using Mossbauer Spectroscopy and electron paramagnetic resonance. Two Mossbauer spectrometers have been used: (i) a high velocity resolution (4096 channels) at 90 and 295 K, (ii) and a low velocity resolution (250 channels) at 20 and 40 K. It is shown that the three studied materials have different superparamagnetic features at various temperatures. This may be caused by different magnetic anisotropy energy barriers, sizes (volume), structures and compositions of the iron cores. The electron paramagnetic resonance spectra of the ferritin, Ferrum Lek and Maltofer® were decomposed into multiple spectral components demonstrating the presence of minor ferro- or ferrimagnetic phases along with revealing marked differences among the studied substances. Mossbauer Spectroscopy provides evidences on several components in the measured spectra which could be related to different regions, layers, nanocrystallites, etc. in the iron cores that coincides with heterogeneous and multiphase models for the ferritin iron cores.
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characterization of monomeric soybean leghemoglobin using Mossbauer Spectroscopy with a high velocity resolution
Hyperfine Interactions, 2014Co-Authors: M I Oshtrakh, V A Semionkin, Arvind Kumar, I V Alenkina, A P Zakharova, Suman KunduAbstract:A preliminary investigation of monomeric soybean leghemoglobin a in oxy- and deoxy-forms was carried out for the first time using Mossbauer Spectroscopy with a high velocity resolution at 90 K. Mossbauer parameters of measured spectra were evaluated and compared with that for the results of the well-known monomeric heme protein, myoglobin.
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Mossbauer Spectroscopy with a high velocity resolution advances in biomedical pharmaceutical cosmochemical and nanotechnological research
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013Co-Authors: M I Oshtrakh, V A SemionkinAbstract:The methodological principles of velocity resolution as additional characteristic of the quality of both Mossbauer spectrometer velocity driving system and Mossbauer spectrum were briefly considered. Significantly better quality of Mossbauer spectra measured with a high velocity resolution in comparison with those measured with a low velocity resolution was demonstrated. The main advances of recent studies of iron containing biomolecules, pharmaceutical products, meteorite samples and nanoparticles using Mossbauer Spectroscopy with a high velocity resolution were considered and advantages of this technique were shown.
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study of rhabdite iron nickel phosphide microcrystals extracted from sikhote alin iron meteorite by magnetization measurements and Mossbauer Spectroscopy
Materials Chemistry and Physics, 2011Co-Authors: M I Oshtrakh, V I Grokhovsky, Yu M Larionov, V A SemionkinAbstract:Abstract Study of rhabdite (iron nickel phosphide) microcrystals extracted from Sikhote–Alin iron meteorite was made using scanning electron microscopy, X-ray diffraction, magnetic measurements and Mossbauer Spectroscopy with a high velocity resolution at various temperatures. The Curie temperature for iron nickel phosphide microcrystals was evaluated in the range of 345–355 K. On the basis of Mossbauer data the temperature dependences of magnetic hyperfine fields for Fe atoms in the M1, M2 and M3 sites of rhabdite were shown as well as Fe and Ni occupancies of these sites were evaluated.
M I Oshtrakh - One of the best experts on this subject based on the ideXlab platform.
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x ray diffraction and Mossbauer Spectroscopy of gandom beryan 008 ordinary chondrite
Hyperfine Interactions, 2019Co-Authors: E V Petrova, A A Maksimova, A V Chukin, M I OshtrakhAbstract:The results of the study of newly found Gandom Beryan 008 H5 ordinary chondrite by means of X-ray diffraction and Mossbauer Spectroscopy with additional characterization by optical and scanning electron microscopy are considered. The main iron-bearing phases and their hyperfine parameters were determined. A comparison of Fe2+ occupancies of the M1 and M2 sites in olivine and orthopyroxene determined by X-ray diffraction and Mossbauer Spectroscopy data demonstrates some consistency and partial oxidation of Fe2+ in olivine.
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an analysis of orthopyroxene from tsarev l5 meteorite using x ray diffraction magnetization measurement and Mossbauer Spectroscopy
Journal of Molecular Structure, 2018Co-Authors: A A Maksimova, A V Chukin, I Felner, R V Kamalov, M I OshtrakhAbstract:Abstract The bulk Tsarev L5 ordinary chondrite powdered matter and chemically extracted orthopyroxene powder were studied using X-ray diffraction, magnetization measurement and Mossbauer Spectroscopy. The unit cell parameters for orthopyroxene in the bulk material and in the extracted powder were the same. Magnetization data also showed similar behavior. However, X-ray diffraction and Mossbauer Spectroscopy revealed residual iron-bearing phases in the extracted powder such as Ca-rich clinopyroxene, chromite and hercynite which were observed in the bulk matter. Additionally, the minor ferrous and ferric components were found in the chemically extracted orthopyroxene powder.
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characterization of northwest africa 6286 and 7857 ordinary chondrites using x ray diffraction magnetization measurements and Mossbauer Spectroscopy
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2018Co-Authors: A A Maksimova, M I Oshtrakh, A V Chukin, I Felner, Grigoriy A Yakovlev, V A SemionkinAbstract:Northwest Africa (NWA) 6286 and 7857 meteorites were studied in detail by using optical microscopy, scanning electron microscopy with energy dispersion Spectroscopy, X-ray diffraction, magnetization measurements and 57Fe Mossbauer Spectroscopy with a high velocity resolution. The main and the minor iron-bearing phases were identified in both meteorites. The unit cell parameters as well as Fe2+ and Mg2+ cation distribution were determined for the M1 and M2 sites in silicate microcrystals. Saturation magnetic moments were obtained for both meteorites. Mossbauer parameters for the main and the minor iron-bearing microcrystals were estimated and compared for NWA 6286 and NWA 7857 LL6 ordinary chondrites. The Fe2+ and Mg2+ cation partitioning, distribution coefficient and temperature of cation equilibrium distribution were estimated for silicate microcrystals using X-ray diffraction and Mossbauer Spectroscopy.
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57fe Mossbauer Spectroscopy and electron paramagnetic resonance studies of human liver ferritin ferrum lek and maltofer
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014Co-Authors: I V Alenkina, M I Oshtrakh, A V Chukin, E Kuzmann, Zoltan Klencsar, V A SemionkinAbstract:Abstract A human liver ferritin, commercial Ferrum Lek and Maltofer® samples were studied using Mossbauer Spectroscopy and electron paramagnetic resonance. Two Mossbauer spectrometers have been used: (i) a high velocity resolution (4096 channels) at 90 and 295 K, (ii) and a low velocity resolution (250 channels) at 20 and 40 K. It is shown that the three studied materials have different superparamagnetic features at various temperatures. This may be caused by different magnetic anisotropy energy barriers, sizes (volume), structures and compositions of the iron cores. The electron paramagnetic resonance spectra of the ferritin, Ferrum Lek and Maltofer® were decomposed into multiple spectral components demonstrating the presence of minor ferro- or ferrimagnetic phases along with revealing marked differences among the studied substances. Mossbauer Spectroscopy provides evidences on several components in the measured spectra which could be related to different regions, layers, nanocrystallites, etc. in the iron cores that coincides with heterogeneous and multiphase models for the ferritin iron cores.
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characterization of monomeric soybean leghemoglobin using Mossbauer Spectroscopy with a high velocity resolution
Hyperfine Interactions, 2014Co-Authors: M I Oshtrakh, V A Semionkin, Arvind Kumar, I V Alenkina, A P Zakharova, Suman KunduAbstract:A preliminary investigation of monomeric soybean leghemoglobin a in oxy- and deoxy-forms was carried out for the first time using Mossbauer Spectroscopy with a high velocity resolution at 90 K. Mossbauer parameters of measured spectra were evaluated and compared with that for the results of the well-known monomeric heme protein, myoglobin.
Bernard Malaman - One of the best experts on this subject based on the ideXlab platform.
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Sn-119 Mossbauer Spectroscopy studies of REMn6Sn6 compounds (RE=Sc, Y, Tb-Tm, Lu)
Journal of Magnetism and Magnetic Materials, 2015Co-Authors: Gérard Venturini, Bernard MalamanAbstract:The ternary compounds REMn6Sn6, compounds (RE-5c, Y, Tb-Tm, LW have been examined by Sn-119 Mossbauer Spectroscopy. The evolution of the transferred hyperfine fields at the three tin sites has been analyzed. The occurrence of isotropic and anisotropic contributions of both the Mn and RE moments is demonstrated. The large variation of the RE atomic size makes evidence of a volume dependence on the hyperfine field transfer constants. The evolution of the hyperfine field in different kinds of magnetic structures suggests a minor contribution of the next-nearest magnetic neighbours. The main magnetic characteristics of the REMn6Sn6 compounds observed by neutron diffraction such as the temperature dependent moment reorientations or the thermal variation of the propagation vector component are in full agreement with the measured Sn-119 hyperfine parameters.
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Sn-119 Mossbauer Spectroscopy of L ` 0.8L0.2Mn6Sn6 compounds (L `=Y, Gd, Tb; L=Gd-Tm, Lu)
Journal of Magnetism and Magnetic Materials, 2014Co-Authors: Gérard Venturini, Pierric Lemoine, Bernard MalamanAbstract:In the HfFe6Ge6-type ferrimagnetic compounds L'0.8L0.2Mn6Sn6 (L' = Y, Gd, Tb; L=Gd-Tm, Lu), the Sn-2e, and Sn-2c sites surrounded by one or three lanthanide atoms split into different sub-sites depending on their (L', L) environment. Sn-119 Mtissbauer Spectroscopy evidences different hyperfine fields characterizing these sub-sites. The field differences are used to evaluate the contributions of the lanthanide moment to the hyperfine field. The analysis suggests isotropic and anisotropic contributions of the spin number of the lanthanide moment and dipolar contributions arising from its g(J)J value. The lanthanide contribution is used to estimate the contribution of the manganese moment alone. The results are consistent with previous Sn-119 Mossbauer Spectroscopy measurements performed on isotypic compounds.
Gérard Venturini - One of the best experts on this subject based on the ideXlab platform.
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Sn-119 Mossbauer Spectroscopy studies of REMn6Sn6 compounds (RE=Sc, Y, Tb-Tm, Lu)
Journal of Magnetism and Magnetic Materials, 2015Co-Authors: Gérard Venturini, Bernard MalamanAbstract:The ternary compounds REMn6Sn6, compounds (RE-5c, Y, Tb-Tm, LW have been examined by Sn-119 Mossbauer Spectroscopy. The evolution of the transferred hyperfine fields at the three tin sites has been analyzed. The occurrence of isotropic and anisotropic contributions of both the Mn and RE moments is demonstrated. The large variation of the RE atomic size makes evidence of a volume dependence on the hyperfine field transfer constants. The evolution of the hyperfine field in different kinds of magnetic structures suggests a minor contribution of the next-nearest magnetic neighbours. The main magnetic characteristics of the REMn6Sn6 compounds observed by neutron diffraction such as the temperature dependent moment reorientations or the thermal variation of the propagation vector component are in full agreement with the measured Sn-119 hyperfine parameters.
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Sn-119 Mossbauer Spectroscopy of L ` 0.8L0.2Mn6Sn6 compounds (L `=Y, Gd, Tb; L=Gd-Tm, Lu)
Journal of Magnetism and Magnetic Materials, 2014Co-Authors: Gérard Venturini, Pierric Lemoine, Bernard MalamanAbstract:In the HfFe6Ge6-type ferrimagnetic compounds L'0.8L0.2Mn6Sn6 (L' = Y, Gd, Tb; L=Gd-Tm, Lu), the Sn-2e, and Sn-2c sites surrounded by one or three lanthanide atoms split into different sub-sites depending on their (L', L) environment. Sn-119 Mtissbauer Spectroscopy evidences different hyperfine fields characterizing these sub-sites. The field differences are used to evaluate the contributions of the lanthanide moment to the hyperfine field. The analysis suggests isotropic and anisotropic contributions of the spin number of the lanthanide moment and dipolar contributions arising from its g(J)J value. The lanthanide contribution is used to estimate the contribution of the manganese moment alone. The results are consistent with previous Sn-119 Mossbauer Spectroscopy measurements performed on isotypic compounds.
V I Grokhovsky - One of the best experts on this subject based on the ideXlab platform.
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study of rhabdite iron nickel phosphide microcrystals extracted from sikhote alin iron meteorite by magnetization measurements and Mossbauer Spectroscopy
Materials Chemistry and Physics, 2011Co-Authors: M I Oshtrakh, V I Grokhovsky, Yu M Larionov, V A SemionkinAbstract:Abstract Study of rhabdite (iron nickel phosphide) microcrystals extracted from Sikhote–Alin iron meteorite was made using scanning electron microscopy, X-ray diffraction, magnetic measurements and Mossbauer Spectroscopy with a high velocity resolution at various temperatures. The Curie temperature for iron nickel phosphide microcrystals was evaluated in the range of 345–355 K. On the basis of Mossbauer data the temperature dependences of magnetic hyperfine fields for Fe atoms in the M1, M2 and M3 sites of rhabdite were shown as well as Fe and Ni occupancies of these sites were evaluated.
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iron nickel alloy from iron meteorite chinga studied by Mossbauer Spectroscopy with high velocity resolution
Hyperfine Interactions, 2009Co-Authors: M I Oshtrakh, V I Grokhovsky, V A Semionkin, N V Abramova, O B MilderAbstract:Study of iron–nickel alloy from iron meteorite Chinga using Mossbauer Spectroscopy with improved velocity resolution (measurement and presentation in 4,096 channels) revealed six magnetic components which may be related to various α-Fe(Ni, Co) and γ-Fe(Ni, Co) phases while previous study with low velocity resolution (in 512 channels) revealed only three magnetic components. This new result was in agreement with the scanning electron microscopy study.
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Mossbauer Spectroscopy with high velocity resolution new possibilities of chemical analysis in material science and biomedical research
Journal of Radioanalytical and Nuclear Chemistry, 2009Co-Authors: M I Oshtrakh, O B Milder, V I Grokhovsky, V A Semionkin, E G NovikovAbstract:An improvement in velocity resolution of Mossbauer Spectroscopy permitted us to carry out a more detailed study of iron chemical state in various iron-containing compounds in a wide range of research. New possibilities of Mossbauer Spectroscopy with high velocity resolution were shown in the studies of meteorites, nanocomposites, pharmaceuticals and biological subjects.
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Mossbauer Spectroscopy with high velocity resolution in the study of iron bearing minerals in meteorites
European Journal of Mineralogy, 2009Co-Authors: V I Grokhovsky, M I Oshtrakh, E V Petrova, Mikhail Yu Larionov, Kseniya A Uymina, V A SemionkinAbstract:Application of Mossbauer Spectroscopy with a higher velocity resolution than commonly applied appeared to be useful for obtaining hyperfine parameters of 57 Fe nuclei with a lower experimental error and for a better fit of complicated spectra. The study of iron-bearing phases in ordinary and carbonaceous chondrites as well as iron meteorite and extracted iron-nickel phosphides by Mossbauer Spectroscopy with an improved velocity resolution (measurement in 4096 channels, presentation in 1024 channels) demonstrated new results which had not been obtained from Mossbauer spectra measured in 512 channels or less. In particular, it was possible to reveal spectral components related to M1 and M2 sites in olivine and pyroxene in Mossbauer spectra of bulk samples of ordinary chondrites and then to evaluate the temperatures of equilibrium cation distribution. Moreover, differences in small variations of Mossbauer hyperfine parameters were obtained for 57 Fe in M1 and M2 sites for both olivine and pyroxene.
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study of iron meteorite sikhote alin and extracted iron nickel phosphides using Mossbauer Spectroscopy with high velocity resolution
Hyperfine Interactions, 2008Co-Authors: M I Oshtrakh, V I Grokhovsky, Yu M Larionov, V A SemionkinAbstract:Comparative study of schreibersite and rhabdite extracted from Sikhote–Alin (IIAB) iron meteorite using Mossbauer Spectroscopy, X-ray diffraction and magnetic measurements was carried out. Mossbauer spectra of bulk meteorite sample and extracted phosphides were recorded in 4,096 channels and then presented in 1,024 channels. Differences of the unit cell structure, the Fe, Ni and Co content, the room temperature Mossbauer spectra and Curie temperature for rhabdite and schreibersite were found.