ON A SPIN-1 ANISOTROPIC XY FERROMAGNET WITH BIQUADRATIC EXCHANGE

A spin-1 XY ferromagnet with crystal field anisotropy parameter D and biquadratic exchange interaction parameter alpha has been investigated using the Green's function technique in the random phase approximatio n. The variation of the Curie temperature T-C as a function of alpha f or different values of D/J has been studied. For small alpha values T- C is found to decrease, whereas for larger alpha, T-C increases. Howev er, for a given value of alpha, T-C increases with D/J.