Irreversible structural changes by heat treatments within the amorphous matrix Fe2O3–Li2O–B2O3

The glass ribbons were fabricated by rapid quenching (RQ) of the Fe2O3–Li2O–B2O3 flux melt between two rotating copper rollers. By thermal annealing of these metastable oxide glasses occurs the crystallization of lithium ferrite (LiFe5O8). The irreversible changes in the structure of the amorphous matrix was detected by X-ray analysis and scanning electron microscopy (SEM). The occurrence of the magnetic phase (LiFe5O8) was proved by magnetization measurements too. The magnetic properties of the thermal treated ribbons (magnetization and coercivity) are correlated with the average size of the ferrite nanoparticles randomly dispersed in the glass matrix.