Ill-Behaved Convergence of a Model of the Gd3Ga5O12 Garnet Antiferromagnet with Truncated Magnetic Dipole-Dipole Interactions

TL;DR

This paper demonstrates that truncating magnetic dipolar interactions in models of Gd3Ga5O12 garnet antiferromagnets leads to unphysical predictions of long-range order, highlighting issues with common approximation methods.

Contribution

It reveals the unphysical nature of truncated dipolar interaction models in Gd3Ga5O12 garnets, similar to previous findings in pyrochlore systems.

Findings

Truncated dipolar interactions predict unphysical long-range order.

The predicted ordering wave vector is highly sensitive to the cut-off distance.

Unphysical phases emerge in the model due to truncation effects.

Abstract

Previous studies have found that calculations which consider long-range magnetic dipolar interactions truncated at a finite cut-off distance Rc predict spurious (unphysical) long-range ordered phases for Ising and Heisenberg systems on the pyrochlore lattice. In this paper we show that, similar to these two cases, calculations that use truncated dipolar interactions to model the Gd3Ga5O12 garnet antiferromagnet also predict unphysical phases with incommensurate ordering wave vector q_ord that is very sensitive to the dipolar cut-off distance Rc.