Study of CuFe2O4–SnO2 nanocomposites by Mössbauer spectroscopy with high velocity resolution

High velocity resolution Mössbauer spectroscopy was used to study of (CuFe2O4)1−x(SnO2)x nanocomposites (x = 0, 1, 5, 10, 20 wt.%). Mössbauer spectra were measured at room temperature with registration in 4,096 channels and further presentation in 1,024 channels. Mössbauer spectra of CuFe2O4 and (CuFe2O4)0.99 + (SnO2)0.01 were better fitted using three sextets while spectra of (CuFe2O4)0.95 + (SnO2)0.05 and (CuFe2O4)0.80 + (SnO2)0.20 were better fitted using four sextets and one doublet. In contrast, spectrum of (CuFe2O4)0.80 + (SnO2)0.20 was better fitted using five sextets and one doublet. Mössbauer hyperfine parameters were related to octahedral and tetrahedral sites in copper ferrites. The presence of two different tetrahedral sites in studied ferrites and two different octahedral sites in (CuFe2O4)0.80 + (SnO2)0.20 was supposed

Comparison of the 57 Fe hyperfine interactions in silicate phases in Sariçiçek howardite and some ordinary chondrites

Silicate crystals have different thermal history in non-differentiated and differentiated meteorites. This leads to some differences in the Fe 2+ and Mg 2+ distribution between the M1 and M2 sites in olivine, orthopyroxene and clinopyroxene crystals in stony meteorites resulting in small variations in the Fe local microenvironment. For this reason, a comparison of Mössbauer hyperfine parameters for the 57 Fe in the M1 and M2 sites in orthopyroxene and Ca-rich clinopyroxene for non-differentiated NWA 6286 LL6, NWA 7857 LL6 and Tsarev L5 ordinary chondrites and differentiated Sariçiçek howardite was carried out. The results obtained demonstrated small variations in quadrupole splitting and isomer shift for the studied non-differentiated and differentiated stony meteorites. © 2019, Springer Nature Switzerland AG.? 02. Türkiye Bilimsel ve Teknolojik Araştirma Kurumu: MFAG/113F035 Ministry of Education and Science of the Russian Federation: 3.1959.2017/4.6Acknowledgements The authors wish to thank G.A. Yakovlev and Dr. M.S. Karabanalov for the help with scanning electron microscopy with energy dispersive spectroscopy. This work was supported by the Ministry of Science and Higher Education of the Russian Federation (the Project ? 3.1959.2017/4.6) and Act 211 Government of the Russian Federation, contract ? 02.A03.21.0006. O.U. acknowledges the Scientific and Technological Research Council of Turkey (the Project number: MFAG/113F035). -