To the mean-field theory of a two-sublattice antiferromagnet

Abstract

Numerical solutions of the mean-field theory of a two-sublattice antiferromagnet with a strong crystalline electric field are studied. The validity of the solutions was checked with the help of known analytical results for the special case of the lowest doublet (S - 1/2). For larger values of the lowest multiplet (S > 1/2) the temperature and magnetic field dependencies of the antiferromagnetic order parameter and the total magnetization are calculated and their features are analyzed. We predict new re-entrant phase transitions between Nеel and paramagnetic phases for S ≥ 1.