A double peak of the coercive force near the compensation temperature in the rare earth iron garnets

The behaviour of the coercive force, H-c, of ferrimagnets near the compensation temperature, T-comp, for polycrystalline rare earth iron garnets R3Fe5O12 (R = Gd, Tb, Dy, Ho and Er) has been studied in detail. The present experimental results have verified the double peak in H-c near T-comp for these rare earth iron garnets R3Fe5O12. For Dy3Fe5O12, the experimental values are T-comp = 24 K, H-c(max) 600 Oe at T-comp +/- delta K and delta approximate to 10 K. The two peaks of H-c arise at 214 and 232 K. The appearance of the double peak of H-c is an intrinsic and characteristic property for R3Fe5O12. The results can be understood on the basis of a simple model. The hysteresis loop in the magnetization is caused by rotation of single domain under the influence of crystalline anisotropy rather than domain wall displacements of the multi-domain structure. The rare earth ion behaves as superimposed paraprocess under the influence of an internal field produced by iron sublattices and a weak exchange magnetic field.