AC susceptibility and temperature modulation studies of gadolinium

Abstract

Studies of the low field (H_rms-1) initial AC susceptibility chi _i of unannealed and annealed gadolinium around the Curie temperature (T_c approximately 290K) are reported. The frequency dependence of chi _i is found to be characteristic of an impurity diffusion magnetic after effect of mean relaxation time tau approximately 0.3 s. A comparison of thermal modulation experiments for annealed and unannealed samples shows that annealing greatly reduces both the observed temperature hysteresis of chi _i and the thermal relaxation of domain properties in the temperature region of domain nucleation.