Eur. Phys. J. B 5, 745-750 (1998)
https://doi.org/10.1007/s100510050498

Quadrupolar order in the S = 2 Heisenberg ferromagnet with the single-ion cubic anisotropy^*

Institute for Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 937, 50-950 Wroclaw 2, Poland

Corresponding author: ^a dudzin@int.pan.wroc.pl

Received: 19 February 1998
Accepted: 17 March 1998
Published online: 15 October 1998

Abstract

The ground state properties of S=2 ferromagnets with isotropic Heisenberg exchange (J) and single-ion cubic anisotropy (D) are studied. The perturbation theory for is used to find an effective Hamiltonian up to the fourth order for 1, 2 and 3 dimensions. It is shown that in opposition to the MFA prediction there is the quadrupolar long range order at T = 0 in the non-magnetic state of the system without a quadrupolar type of interaction. The effect is a consequence of the quantum nature of the model.