Magnetostriction of magnesium ferrous ferrites

Magnetostriction constants λ111and λ100of single crystals of magnesium ferrous ferrites MgxFe3-xO4were measured from 80 to 320 K in the composition range . The single crystals were obtained by zone melting polycrystalline rods, which were prepared by sintering mixtures of very pure Fe2O3and MgO. The constant λ111at room temperature of this ferrite series is proportional to the third power of the oetahedral sublattice magnetization, suggesting that λ111is mainly determined by the octahedral Fe²⁺ions. For compositions with x > 0.6, λ111is nearly temperature independent, while for x < 0.3 this magnetostriction decreases gradually with decreasing temperature, reaching negative values at about 100 K. Further it 0was found that the average magnetostriction at 300 K ( ) decreases nearly linearly with x, being zero at x = 0.92. The constant λ100changes slightly with composition and temperature ( ).