Uniform susceptibility of classical antiferromagnets in one and two dimensions in a magnetic field

Abstract.

We simulated the field-dependent magnetization m(H,T) and the uniform susceptibility x of classical Heisenberg antiferromagnets in the chain and square-lattice geometry using Monte Carlo methods. The results confirm the singular behavior of x at small T,H: lim_T→₀ lim_H→₀ X(H,T)=1/(2J₀)(1-1/D) and lim_T→₀ lim_H→₀ X(H,T)=1/(2J₀), where D=3 is the number of spin components, J ₀=zJ, and z is the number of nearest neighbors. A good agreement is achieved in a wide range of temperatures T and magnetic fields H with the first-order 1/D expansion results (D.A. Garanin, J. Stat. Phys. 83, 907 (1996)).