Effect of Hydrostatic Pressure on the Curie Points of Several Ferrites

The effect of hydrostatic pressure on the Curie temperature Tc was measured for four members of a Ni–Zn ferrite series (30%, 50%, 80%, and 100% NiO) and for two members of a gadolinium-iron-garnet series (Gd3AlFe4O12 and Gd1.5Y1.5Al0.5Fe4.5O12). A transformer technique was used for the measurements with the maximum pressure available being 8 kbar. The Curie temperature showed a linear increase with pressure and the slopes ranged from 0.58±0.05 to 1.16±0.07°C/kbar. The approximate Curie points varied from 153°C (Gd3AlFe4O12) to 616°C (100% NiO ferrite). The samples with Tc less than 400°C were measured in a liquid-pressure system and the others were measured in a gas-pressure system.