Click here to view fulltext PDF

Permanent link:
https://www.ias.ac.in/article/fulltext/pram/008/03/0286-0291

Anisotropic ferromagnet; biquadratic exchange

A formulation, using the double time Green’s function method, is presented for the anisotropic spin-one ferromagnetic system in the presence of Ising part of the biquadratic exchange and an expression is given for the critical temperatureT_c in terms of two parameters. One is associated with the uniaxial anisotropy (treated exactly) and the other one corresponds to the biquadratic interaction (treated in RPA). The bilinear Heisenberg exchange term is treated in Callen’s approximation emphasizing the role of intersite correlation for small parameters. The prediction thatT_c increases with the biquadratic exchange is found to be consistent with the recent calculation based on high temperature series expansion.

Vijay Kumar¹ K C Sharma¹

1. Department of Physics, Himachal Pradesh University, Simla - 171005

Published

March 1977

Manuscript received

28 June 1976

Manuscript revised

18 October 1976