Central Institute of Physics, IFTM, P.O. Box 5206, Bucharest, Romania
Abstract:
The magnetic measurements performed on xFe2O3(1-x)B2O3 · PbO] glasses show that for x 5 mol.% Fe2O3 the thermal variation of reciprocal susceptibility obeys a Curie behaviour. For higher iron content, at T 50 K, a nonlinear variation, typical for systems with random distribution of exchange interactions is observed. At greater temperatures than 50 K a Curie-Weiss behaviour is shown. The composition dependence of the Curie constants is analysed in correlation with the number of Fe3+ and Fe2+ ions as determined from Mössbauer effect measurements. A comparison with the data obtained in case of xFe2O3(1-x)3B2O3 · PbO] glasses is made.