Three dimensional ferromagnetic ising 'fluid' model

Abstract

The tree dimensional ferromagnetic spin-half Ising model with an arbitrary external magnetic field is considered in the spatial continuum limit and under a certain tempering condition to be imposed on the pair-wise spin-spin interaction. An expression for the partition function has been obtained for a tempered. RKKKY type interaction. The solution predicts the classical mean-field behaviour above a critical temperature below which the spontaneous magnetization jumps discontinuously from zero to the saturation value.