Magnetic studies of TeO2 – Fe2O3 glass systems obtained by the sol – gel method

Abstract

Glass of the xFe2O3(1-x)TeO2 systems with x = 0.03–0.40 were obtained by sol-gel method and studied by magnetic susceptibility measurements. The temperature dependence of the reciprocal magnetic susceptibility follows a Curie law till 10 mol% Fe2O3 and over this concentration follows a Curie- Weiss law with the negative paramagnetic Curie temperature. The main result coming out from this behaviour is: at concentrations lower than x = 10 mol% Fe2O3 iron ions are isolated or participates at dipolar interactions and at concentrations larger than 10 mol% Fe2O3 a higher part of iron ions participates at superexchange magnetic interactions.