Nature of Partial Magnetic Order in the Frustrated Antiferromagnet Gd2Ti2O7

TL;DR

This study investigates the partial magnetic order in Gd2Ti2O7, revealing a complex 2-k structure with suppressed moments and enhanced fluctuations, supporting theories of fluctuation-driven order in frustrated magnets.

Contribution

It provides detailed experimental evidence of the 2-k partial order in Gd2Ti2O7 using neutron scattering and spin-wave analysis, confirming theoretical predictions.

Findings

Identification of a 2-k magnetic structure with suppressed moments

Observation of enhanced spin-wave fluctuations

Experimental support for fluctuation-driven order theories

Abstract

Partially-ordered magnets are distinct from both spin liquids and conventional ordered magnets because order and disorder coexist in the same magnetic phase. Here, we determine the nature of partial order in the canonical frustrated pyrochlore antiferromagnet Gd$_2$Ti$_{2}$O$_{7}$. Using single-crystal neutron-diffraction measurements in applied magnetic field, magnetic symmetry analysis, inelastic neutron-scattering measurements, and spin-wave modeling, we show that its low-temperature magnetic structure involves two propagation vectors (2-$\mathbf{k}$ structure) with suppressed ordered magnetic moments and enhanced spin-wave fluctuations. Our experimental results support theoretical predictions of thermal fluctuation-driven order in Gd$_{2}$Ti$_{2}$O$_{7}$.