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

Abstract

The behaviour of the coercive force, H _c, of ferrimagnets near the compensation temperature, T _comp, for polycrystalline rare earth iron garnets R ₃Fe₅O₁₂ (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 R ₃Fe₅O₁₂. For Dy₃Fe₅O₁₂, the experimental values are T _comp = 224 K, H _c(max) = 600 Oe at T _comp ± δ K and δ ≈ 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 R ₃Fe₅O₁₂. 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.

Acknowledgements

The authors would like to thank Dr. J. Awaka, Mr. T. Oriuchi and Mr. M. Sakuraoka for their valuable help of experiments.