Remanence and relaxation in a mictomagnet

The thermoremanent magnetization was measured for ${\mathrm{Cu}}_{75}$ ${\mathrm{Mn}}_{25}$ (quenched from 900°C) after cooling from 300 K to temperatures from 1.6 to 50 K in magnetic fields ranging from 6 to 50 kOe. The isothermal relaxation of the remanence was measured up to 120 sec at each temperature after the field became zero. The rate of isothermal relaxation was found to increase with the field to which the specimen had been exposed during cooling.