Mossbauer Investigation of the Chelyabinsk Meteorite Fragment

The article devoted to study of the fragments of Chelyabinsk meteorite with the help of Mossbauer spectroscopy. It is shown that the iron in various fragments of the meteorite exist in different crystallographic, physical and chemical conditions. A new phenomenon of sharp increasing effective magnetic field in the region of the iron nuclei in the temperature range of 553-573 К and jumps of the main parameters of Mossbauer spectra at other temperatures are observed. According to the data of the isomer shifts and quadruple splitting of the individual spectra, iron ions have a valence of Fe2+ − 3d6, Fe3+ − 3d5, Fe4+ − 3d4, Fe6+ − 3d2 and also intermediate between them. A qualitative explanation of the experimental data is proposed.

Study of Point Defects in Fe-Al System by Mössbauer Spectroscopy and XRD Method

In this work, the Mössbauer spectroscopy employed in a study of point defect formation in intermetallic phases of the B2 structure from the Fe-Al system as a function of Al concentration. We present the values of the 57Fe isomer shift and quadruple splitting for the components describing the point defect in the local environment of a Mössbauer nuclide. The concentration of the Fe vacancies and Fe atoms substituting Al (Fe-AS) are determined. The results shown that an increase in Al content causes an increase in vacancy and Fe-AS concentration.

A Study of Point Defects in the B2-Phase Region of the Fe–Al system by Mössbauer Spectroscopy

In this work, we employed the Mössbauer spectroscopy in a study of point defect formation in intermetallic phases of the B2 structure from the Fe-Al system as a function of Al concentration. We present the values of the 57Fe isomer shift and quadruple splitting for the components describing the point defect in the local environment of a Mössbauer nuclide. The concentration of the Fe vacancies and Fe atoms substituting Al (Fe-AS) are determined. The results shown that an increase in Al content causes an increase in vacancy and Fe-AS

Characterization of superparamagnetic MgxZn1−x Fe2O4 powders

Structural and magnetic properties of Mgx Zn1−x Fe2O4 powders have been studied with respect to the application for thermal cancer therapy (magnetic hyperthermia). Mgx Zn1−x Fe2O4 (x=0.1–0.5) powders with particle sizes between 5 and 8 nm were produced by citrate method. The X-ray diffraction patterns of the samples correspond to a spinel phase. The lattice constant and the volume of the elementary cell increase when x changes from 0.1 to 0.5. The FTIR-spectra ascertain the spinel phase formation. The Mossbauer studies reveal the presence of extremely small particles, which undergo superparamagnetic relaxation at room temperature. The core-shell model has been applied to explain quadruple doublets. The quadruple splitting at “shells” is bigger than those at “cores” whereas the isomer shifts remain close. Magnetic studies confirm the presence of extremely small particles that behave as superparamagnetic ones.