FEATURES OF THE FERROMAGNETIC STATE IN A MAGNET WITH ORBITAL ORDERING

The features of temperature and field behavior of the ferromagnetic state in the two-spin Kugel–Chomsky model describing the relationship between the ferromagnetic spin and antiferromagnetic pseudospin orbital orderings are investigated. The case is analyzed when the critical temperature of the antiferromagnetic orbital ordering Tl is higher than the critical Curie temperature of the spin ferromagnetic order Ts. It is
shown that in this case the existence of an exchange coupling of the ferromagnetic spin subsystem with the orbitally ordered subsystem leads at finite temperatures to a decrease in both the spontaneous and induced magnetization of the ferromagnetic state compared to similar characteristics of the ferromagnetic state in a media without orbital ordering.