Scaling analysis of minor hysteresis loops in ferromagnets with large uniaxial anisotropy

Scaling power-law rules of minor hysteresis loops have been examined in the wide temperature range for Co and Gd polycrystals. While the usual Steinmetz law between hysteresis loss and maximum magnetization holds true for Gd with weak magnetocrystalline anisotropy, a large deviation of the Steinmetz exponent from 1.6 to 2.1 was obtained for Co, possibly due to the strong uniaxial anisotropy which results in a largely different magnetic response for each grain against applied fields. On the other hand, a scaling power-law rule between hysteresis loss and remanence of the minor loops was found to be universal and almost the same exponent of 1.4 was obtained, being independent of types of ferromagnets and temperature. These observations were explained on the basis of Rayleigh law.