Temperature dependence of the magnetic properties of ferromagnetic amorphous alloys

The magnetic hysteresis properties of amorphous alloys have recently been discussed in terms of an exchange-enhanced applied field. This absolute-zero model is here extended to finite temperatures. The modified treatment predicts a remanent magnetization which is unaffected by thermal activation while the coercive force falls (finally to zero) as temperature increases. Comparison with experiment for Tb${\mathrm{Fe}}_2$ suggests that regions of volume ≃ 7500 ${\mathrm{\AA }}^3$ reverse coherently.