Magnetic susceptibility of amorphous and heat-treated vanadate glasses

X-ray diffraction and magnetic susceptibility measurements were used to study the effect of addition of iron on the crystallization process and magnetic properties of the vanadium borophosphate system before and after heat treatment. The glass composition was 78 mol% V2O5-15 mol% P2O5-7 mol% B2O3, the Fe2O3 was added with concentration ranging from 0.05 up to 1 mol%. The X-ray diffraction showed that the V2O5 was the only phase separated during the heat treatment process. The intensity of the characteristic V2O5 peaks increased with increasing Fe2O3 content. The magnetic susceptibility was found to decrease for the sample containing 0.05 mol% Fe2O3. This could be explained by the presence of most of the iron ions in the ferrous state and the presence of a covalent bond between the ferrous ions and the oxygen ions. An increase in the magnetic susceptibility was found in samples containing an iron content of more than 0.05. This increase could be explained according to the change of Fe2+ ions to Fe3+ which has higher paramagnetic behaviour.