2018/08/13 by Chamati, Hassan, Shopova, Diana V.
#FOS: Physical sciences #Other Condensed Matter (cond-mat.other)
paper · doi:10.48550/arxiv.1808.04326
We study phenomenologically on the basis of two bilinearly coupled Heisen- berg models the phase diagram of some ferrimagnetic substances. Calculations are performed with the help of Landau energy obtained through applying the Hubbard-Stratonovich transformation to the initial microscopic Heisenberg Hamiltonian. The phase transitions within the model are of second order with the emergence of a compensation point at lower temperatures for some values of parameters of the system. The main phase is a two-sublattice collinear ferrimagnet but also a metastable non-collinear phase is present within the exchange approximation presented here. The numerical results give a detailed description of temperature dependence of magnetization on the strength of in- tersublattice interaction and the difference between the effective exchanges of two ferromagnetically ordered sublattices.