On the magnetic phase transition in terbium ferrite-garnet

It is shown that anomalies on the magnetization curves of the samples of terbium ferrite-garnet (Tb₃Fe₅O₁₂) revealed by Tran Khanh Vien and Dormann [1] are due to the first order spin-reorientation phase transition in iron sublattices. This transition is satisfactorily described by the simple phenomenological theory taking into consideration only anisotropic interactions.