Morin transition suppression in Polycrystalline 57Hematite (α-Fe2O3) exposed to 56Fe(II)

摘要

We used the isotope selectivity of 57Fe M?ssbauer spectroscopy to investigate changes in the magnetic properties of polycrystalline hematite exposed to ferrous iron (Fe(II)). We found that sorption of 56Fe(II), followed by interfacial electron exchange, alters the bulk magnetic properties of 57hematite. After reaction with 56Fe(II), we observed partial suppression of the Morin transition of 57hematite to below 13 K. This is significantly lower than the Morin temperature (T M) of ～230 K measured for isotopically enriched polycrystalline 57hematite, as well as the T M of 264 ± 2 K reported for normal polycrystalline hematite.