S. Ambe et al., IN-SITU EMISSION MOSSBAUER STUDIES ON CARRIER-FREE CO-57(2-119(5+) IONS AT INTERFACES BETWEEN SPINEL-TYPE OXIDES AND AQUEOUS-SOLUTIONS() AND SB), Radiochimica Acta, 80(2), 1998, pp. 101-108
Surface chemical states of carrier-free Co-57(2+) and Sb-119(5+) ions
adsorbed on gamma-Fe2O3 and NiFe2O4 were studied in the presence of th
e aqueous phase using the magnetic interaction between the substrates
and Fe-57(3+) Or Sn-119(4+) arising from the adsorbed species. Two che
mical forms were observed for the Co-57(2+) adsorbed on gamma-Fe2O3, o
ne giving a peak in the high-field region and another giving a broad d
istribution in the low field. They were attributed to Co-57(2+) at sur
face B sites of the spinel structure of gamma-Fe2O3 and Co-57(2+) spec
ies weakly bonded to the substrate, respectively. In case of NiFe2O4,
the latter species was dominant, being converted to the former by heat
ing. Most of the Sb-119(5+) ions adsorbed on the gamma-Fe2O3 and NiFe2
O4 particles were found to have more or less magnetic interaction with
the magnetically ordered ions of the substrates.