Field-Driven Transitions in the Dipolar Pyrochlore Antiferromagnet Gd$_2$Ti$_2$O$_7$

TL;DR

This paper develops a mean-field theory to describe magnetic field-driven phase transitions in the dipolar pyrochlore antiferromagnet Gd$_2$Ti$_2$O$_7$, explaining experimental neutron scattering results and predicting new phases and transitions.

Contribution

It introduces a mean-field model capturing complex phase behavior and local disorder parameters in Gd$_2$Ti$_2$O$_7$, advancing understanding of dipolar pyrochlore systems.

Findings

Identification of an 8-sublattice antiferromagnetic phase with coexisting ordered and fluctuating moments

Prediction of multiple field- and temperature-driven phase transitions

Discovery of local disorder parameters characterizing the transitions

Abstract

We present a mean-field theory for magnetic field driven transitions in dipolar coupled gadolinium titanate Gd$_2$Ti$_2$O$_7$ pyrochlore system. Low temperature neutron scattering yields a phase that can be regarded as a 8 sublattice antiferromagnet, in which long-ranged ordered moments and fluctuating moments coexist. Our theory gives parameter regions where such a phase is realized, and predicts several other phases, with transitions amongst them driven by magnetic field as well as temperature. We find several instances of {\em local} disorder parameters describing the transitions.