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1.
Results showing the influence of optical thickness of a scatterer in selective-excitation double M?ssbauer spectroscopy are
presented on the example of α-Fe and FeBO3. Significant transformation of the spectral γ-radiation structure predicted theoretically is demonstrated for single-layered
FeBO3. 相似文献
2.
I. I. Ali-Zade Yu. F. Babikova O. M. Vakar Yu. V. Petrikin 《Russian Physics Journal》1987,30(9):738-740
A semiempirical formula is derived for evaluating the lowest concentration of Mössbauer atoms whose signal can be reliably recorded by electron Mössbauer spectroscopy. The concentration is calculated from the resonance effect magnitude in a sample of known chemical composition, on the basis of the cross sections of photoelectric absorption of source gamma photons by the sample atoms, the energy and probability of production of photoelectrons and their associated Auger electrons, and the probability of recoilless gamma-photon absorption in the sample. Experimental testing showed that the calculated and measured values of differ by not more than 20%.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 20–23, September, 1987. 相似文献
3.
U. Gonser 《Hyperfine Interactions》1983,13(1-3):5-23
In this anniversary contribution the natural and intimate match making which occurs between the two star performers-57Fe in Mössbauer spectroscopy and iron in physical metallurgy—is described by selecting typical examples reflecting the author's interest: phases, f.c.c. -Fe, defects, diffusion and amorphous metals. 相似文献
4.
The aim of this paper is to highlight some selected research activities on molecular magnetic materials using Mössbauer spectroscopy as a technique carried out in our laboratory in recent years. The first part of the present article is devoted to the studies of the various magnetic interactions, metal-to-metal electron-transfer phenomenon, glass transition occurring in molecular magnetic materials, whereas the second part deals with the iron(II) high spin (S = 2)–low spin (S = 0) transition phenomenon occurring in some isoxazole ligand based iron(II) compounds as examples with unusually complicated spin transition behaviour. Also, an example of a dinuclear a spin crossover compound of iron(II) is described, where Mössbauer spectroscopy has most convincingly unraveled the mechanism of the spin transition process. Finally, an example from our most recent studies of spin crossover materials exhibiting both thermal spin crossover and liquid crystalline properties in the same temperature interval near room temperature will be presented. 相似文献
5.
Mössbauer investigations of zirconium alloys were examined. Data about the chemical state of iron atoms in the zirconium alloys of different composition has been provided. Mössbauer spectroscopy revealed that small quantities of iron in binary zirconium alloy are in the solid solution α-Zr (up to 0.02 wt.%). Different iron atoms concentration and thermo-mechanical treatments may lead to formation the intermetallic compounds Zr3Fe, Zr2Fe, ZrFe2. Adding tin atoms does not affect the formation and shape of Mössbauer spectra of these compounds. Adding Cr and Nb atoms makes significant changes in the shape of Mössbauer spectra and leads to the formation of complex intermetallic compounds. Adding Cu and W atoms, the shape of the binary alloys spectra (Zr-Fe) remains unchanged, but a change in the temperature dependence behavior of the spectral parameters occurs and also, changes to the properties of the alloys. 相似文献
6.
A possibility of conversion electron Mössbauer spectroscopy for determining the gas molecular state is shown. For acceleration of gas interaction with active surface the thin iron layer enriched with 57Fe was applied on aluminum foil and gas discharge is used. 相似文献
7.
V. V. Popov A. V. Stolbovsky A. V. Sergeev V. A. Semionkin 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(7):860-864
The applicability of Mössbauer spectroscopy in studying grain boundaries in ultrafine-grained materials produced by severe plastic deformation (SPD) is analyzed. It is shown that grain boundaries after SPD are in a nonequilibrium state that is characterized by excess free volume. 相似文献
8.
9.
S. V. Stolyar O. A. Bayukov V. P. Ladygina R. S. Iskhakov L. A. Ishchenko V. Yu. Yakovchuk K. G. Dobretsov A. I. Pozdnyakov O. E. Piksina 《Physics of the Solid State》2011,53(1):100-104
Ferrihydrite nanoparticles formed as a result of the microorganism activity have been studied using Mössbauer spectroscopy, X-ray powder diffraction analysis, and X-ray fluorescence analysis. Three positions of trivalent iron with nonoverlapping ranges of quadrupole splittings have been revealed in bacterial ferrihydrite: QS{Fe3+(1)} = 0.49–0.83 mm/s, QS{Fe3+(2)} = 0.84–1.10 mm/s, and QS{Fe3+(3)} = 1.25–1.73 mm/s. It has been experimentally demonstrated that the Fe3+(3) positions are the centers of nucleation of the hematite phase in the course of heat treatment. 相似文献
10.
P. C. Morais 《Hyperfine Interactions》2008,181(1-3):1-12
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 Mössbauer 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 Mössbauer spectroscopy in accessing information regarding the nanoparticle modification due to the empirical process which provides long term chemical stability is included in the paper. 相似文献
11.
L. D. Zaripova N. V. Boltakova A. A. Valiullin Sh. Sh. Bashkirov 《Technical Physics》2005,50(4):473-478
Complex perovskite-like oxides, such as LnFe2/3Mo1/3O3 orthoferrites, Ln8?ySryCu8?xFexO20 (8-8-20), Pr4BaCu4FeO13-δ(4-1-5), YBa2-yLa y Cu3-xFe x O7-δ and Y1-yCa y Ba y La y Cu3-xFe x O7-δ (1-2-3), are studied by means of Mössbauer spectroscopy. At room temperature, the spectra of the orthoferrites contain only magnetic components. The spectra of the 1-2-3 compounds contain only magnetically disordered components: iron atoms substitute for copper at Cu(1) sites, taking various configurations: planar squares, quadratic pyramids, and octahedra. Cuprates 8-8-20 and 4-1-5 have a wide diversity of spectra. In the 8-8-20 oxides, a phase related to the pyramidal environment of the iron cations is present at any iron concentration. In all the perovskites, iron cations become magnetically ordered only at octahedral sites of the structure. 相似文献
12.
C. I. Wynter D. H. Ryan Olga Trichtchenko C. J. Voyer D. E. Brown S. G. Sobel A. L. Haigney Leopold May B. R. Hillery N. S. Gajbhiye 《Hyperfine Interactions》2008,185(1-3):123-127
We have previously reported the stability of europium oxalate compared to ammonium europium bis-salen and europium benzoate. We now extend the dicoarboxylic acid chain of the oxalate by introducing additional-CH2-groups in the dicarboxylate ligands by using malonate, succinate, glutarate and adipate. Additionally, we have examined the effect of alterations in the succinate dianion by introducing functional groups such as [C = C]in the case of the maleide and-OH group in the case of the malide. This study is an attempt to further characterize these compounds. Infrared spectra were used to characterize bridging and chelating dicarboxylates while Mössbauer spectroscopy measurements were used to gain better insight into the structure of heterocyclic “cages” containing two Eu3?+? ions and two dianions. 相似文献
13.
The setting up and updating of a Mössbauer laboratory imply the acquisition and assembling of different units. Guidelines concerning either the construction or the acquisition of the various parts which compose a Mössbauer spectrometer are given in this paper. 相似文献
14.
The procedures and results of high resolution Mössbauer experiments performed with the 93.3 keV resonance in absorbers of67ZnO,67ZnS (both wurtzite and sphalerite structures),67ZnSe,67ZnTe and67ZnF2 are reported. An essentially linear dependence between the isomer shift and the Pauling electronegativity of the ligands was found. A value of r
2=+11×10–3 fm2 is estimated. The Mössbauer parameters for both ZnS structures are equal within present limits of error. In particular, no quadrupole interaction was observed in the wurtzite modification. This indicates a nearly identical local symmetry at the Zn site in the two ZnS structures.Work supported by the Bundesministerium für Forschung und Technologie, Federal Republic of Germany and the Kernfor-schungszentrum Karlsruhe 相似文献
15.
《Current Applied Physics》2015,15(3):226-231
Studies of the ferrite nanoparticles prepared by the chemical decomposition of iron chlorides with a various ratio ξ = Fe3+/Fe2+ are herein presented. The microstructure and the magnetic properties have been studied by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Mössbauer spectroscopy (MS). The TEM studies show that the nanoparticles have almost a spherical shape with the diameter of (12 ± 2) nm for all samples. The measured XRD pattern was mainly composed of lines which were indexed with a cubic spinel structure. The analysis of the Mössbauer data shows that the microstructure of the nanoparticles consists of the core formed by nonstoichiometric magnetite and maghemite shell. A small amount of hematite, probably on the surface of the nanoparticles with ξ = 1.75, 2.0, was detected. At temperatures T ≤ 150 K the spin canting of surface maghemite with ξ = 2.25 was observed while for the samples with ξ = 1.75, 2.0 such effect was suppressed by the presence of hematite on the surface of the nanoparticles. Infield Mössbauer spectra with ξ = 1.75, 2.0 show that magnetic moments of the magnetite/maghemite core are parallel while magnetic moments of the surface hematite are perpendicular to the direction of the external magnetic field. 相似文献
16.
F. J. Berry I. S. Lyubutin M. F. Thomas V. A. Sarkisyan T. V. Dmitrieva 《Hyperfine Interactions》2008,184(1-3):23-26
The tin-doped sulphur-containing compound of composition Fe1.05Cr1.90Sn0.05S4, in which tin is located on the octahedral sites as Sn4?+? in the spinel-related structure, has been examined by 119Sn Mössbauer spectroscopy. The data complement results obtained by 57Fe Mössbauer spectroscopy and show that tin increases the magnetic ordering temperature of pure FeCr2S4. 相似文献
17.
L.-W. Yin M.-S. Li Z.-Y. Hao Y.-J. Bai Z.-G. Gong F.-Z. Li 《Applied Physics A: Materials Science & Processing》2001,73(5):535-538
M?ssbauer spectroscopy has been used to systemically study the catalytic mechanism of Fe-based alloys in diamond formation
at high temperature–high pressure (HTHP) for the first time. M?ssbauer spectra reveal the magnetic state of the 3d electrons
of a Fe atom in the Fe-based alloy catalyst during diamond formation at HTHP. During carburization at lower temperatures than
that required for diamond formation and diamond formation in the diamond-stability region using Fe-based alloys as a catalyst,
both the quadrupole splitting QS and the isomer shift IS change from negative to positive, especially reaching a state in
which they are zero. It was indicated that the state of the 3d-shell electrons of the iron atom changes greatly during carburization
and diamond formation and that the incomplete 3d sub-bands of Fe atoms in the catalyst alloys could be filled up in proper
order by electrons of interstitial carbon atoms. During diamond formation, the unpaired 3d-shell electrons of an iron atom
in the Fe-based alloy absorb and interact with 2Pz electrons of the carbon atoms. There exist a Fe–C bonding and an electron charge transfer stage. The 2Pz electrons of the carbon atoms could be dragged into the metal atoms in the catalyst alloy and would make a transition of
triangular (sp2π) hybridization of valence electrons to tetrahedral (sp3) hybridization of valence electrons (a transition of sp2π bonds of graphite to sp3 bonds of diamond), resulting in a transition of graphite structure to diamond. Although the conclusion of this study is strictly
applicable only to Fe-based alloy catalysts, it could be considered more general because of the chemical similarities between
the transition elements used as solvent catalysts for diamond synthesis.
Received: 2 March 2001 / Accepted: 20 August 2001 / Published online: 2 October 2001 相似文献
18.
19.
D. G. Rancourt 《Hyperfine Interactions》1988,40(1-4):183-194
Magnetic cluster excitations in various physical systems (e.g., soliton bearing one-dimensional solids, metallic alloys, amorphous materials, small particle aggregates, magnetically ordered substances near TC, transition metal di-chloride graphite intercalation compounds, etc.) are described. Use of Fe-57 Mössbauer effect spectroscopy as a probe of the spin dynamics for inverse autocorrelation times between 107Hz to 1010 Hz is emphasized. Particular attention is given to systems which exhibit local or long range magnetic order and whose Mössbauer spectra must therefore be described by more than one autocorrelation (or dwell) time for fluctuations between different allowed hyperfine field directions on a given site. 相似文献
20.
Intermetallic phases and solid solutions in the Zr-rich region of the Zr–Nb–Fe system with low Nb content are studied by Mössbauer 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 Ti2Ni type phase with a similar stoichiometry to the tetragonal Zr2Fe compound. Mössbauer 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(βT) phase (IS: (-0.24 α 0.02) mm/s, QS: (0.45 α 0.02) mm/s). 相似文献