Mean-field phase diagrams of $AT_2X_2$ compounds

TL;DR

This paper calculates magnetic-field--temperature phase diagrams of the axial next-nearest-neighbor Ising model using Landau expansion and molecular-field theory, showing qualitative agreement with experimental data on $UPd_2Si_2$ and relevance for similar compounds.

Contribution

It introduces a Landau-type expansion approach to analyze phase diagrams of the axial next-nearest-neighbor Ising model, aligning theoretical predictions with experimental findings.

Findings

Qualitative agreement with $UPd_2Si_2$ phase diagrams

Effective Landau expansion captures key features

Applicable to related $AT_2X_2$ compounds

Abstract

Magnetic-field -- temperature phase diagrams of the axial next-nearest-neighbor Ising model are calculated within the framework of a Landau-type expansion of the free energy derived from molecular-field theory. Good qualitative agreement is found with recently reported results on body-centered-tetragonal $UPd_2Si_2$. This work is expected to also be relevant for related compounds.