Pressure effect of Fe-29 wt% Ni alloy ultrafine particles

Fe–29 wt% Ni alloy ultrafine particles with various average sizes are prepared by the evaporation-condensation method. They are compressed into disks or small rings under different pressures. As the pressure increases, martensitic volume fraction and specific saturation magnetization σ s increase markedly, while coercivity H c exhibits a linear decrease. The complex permeability varies with the pressure. Its high-frequency characteristic is far superior to that of bulk. The effect of pressure depends on the average size *BAR*d*BAR*.