Mossbauer and magnetization measurements have been made on a [(SiO 2)45(Ca0)55]65[Fe2O 3]35 glass equilibrated at 1550°C in a variable oxygen partial pressure atmosphere. The concentration of Fe2+ cations, as determined by Mossbauer analysis, is observed to increase with lower p O2 pressures at the expense of the fraction of Fe3+ cations tetrahedrally coordinated. The Fe2+ doublet is found to display the largest isomer shift and quadrupole splitting. For the two types of ferric cations there appears to be a general tendency for the Fe3+ cations with lower coordination to have a lower isomer shift but a substantially larger quadrupole splitting. Room temperature magnetization data indicate all the samples to contain superparamagnetic particles which increase in abundance with lower pO2 pressures. The superparamagnetic behavior is attributed to the formation of ferrite precipitates which occur during quenching.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)