Magnetic susceptibility of quasi-one-dimensional Ising superantiferromagnets FeTAC and MCl_2*2NC_5H_5 (M=Co, Fe): Approximations with L x oo and L x L x oo chain clusters

TL;DR

This paper develops a method to analyze magnetic susceptibilities of anisotropic Ising magnets using chain cluster approximations, providing improved estimates of interchain coupling from experimental data.

Contribution

It introduces a new approximation approach for 2D and 3D anisotropic Ising lattices using chain clusters, enhancing the accuracy of interchain coupling estimates.

Findings

Quantitative description of experimental susceptibilities for FeTAC and related magnets.

Proposed method significantly improves J'/J estimation accuracy.

Applicable across entire temperature range for studied materials.

Abstract

The temperature dependence of the zero-field susceptibilities of 2D and 3D Ising lattices with anisotropic coupling is analyzed. Infinite 2D and 3D lattices are approximated, respectively, by ensembles of independent L x oo and L x L x oo chain clusters that are infinitely long in the strong-coupling (J) direction. This approach is used as a basis for a quantitative description of available experimental data on the magnetic susceptibilities of the 2D anisotropic Ising magnet [(CH_3)_3NH]FeCl_3*2H_2O (FeTAC) and the quasi-one-dimensional 3D magnets CoCl_2*2NC_5H_5 and FeCl_2*2NC_5H_5 in the entire experimental temperature range. A method is proposed for determining the relative interchain coupling strength J'/J from the maximum susceptibility value, which improves the accuracy of estimates for J'/J by more than an order of magnetude.