Magnetic properties of partially devitrified B2O3-MnFe2O4 glass

Crystallization processes of partially devitrifled glass obtained by rapid quenching of 0·17₅ MnO + 0·17₅. Fe₂O₃ + 0·65 B₂O₃ melt were studied by DTA and X-ray analyses and the temperature regions of nucleation, crystallization and decompozition of the spinel phase were established. The magnetization curves measured between 4·2 and 250 K in magnetic fields up to 42 kOe divided the samples into two groups: the original as cast glass and those annealed below the crystallization temperature, as well as above the decomposition temperature showed essentially paramagnetic behaviour, whereas those annealed closely above the crystallization temperature displayed a spontaneous magnetic moment. The former ones could not be classified as superparamagnetic but the temperature dependence of their susceptibility could be explained by interactions of the antiferromagnetic type. The comparison of lattice parameter and Curie temperature of the latter one with crystalline Mn _x Fe_3-x O₄, system indicated pronounced iron enrichment of the spinel phase formed during heat treatment.Based on a paper presented at the Conference of Socialist Countries on Magnetic Oxides and Compounds; Reinhardsbrunn bei Friedrichroda, GDR, October 22nd–27th, 1972.The authors thank Mrs. A.Hadincová for the help with the evaluation of the results.