Evidence for gapped spin-wave excitations in the frustrated Gd2Sn2O7 pyrochlore antiferromagnet from low-temperature specific heat measurements

TL;DR

This study measures the low-temperature specific heat of Gd2Sn2O7, revealing a gapped spin-wave spectrum caused by anisotropy, and fits the data with linear spin-wave theory to determine exchange interactions.

Contribution

It provides experimental evidence for a gapped spin-wave spectrum in Gd2Sn2O7 and confirms the applicability of linear spin-wave theory to this frustrated antiferromagnet.

Findings

Exponential drop in specific heat below 350 mK

Evidence for a gapped spin-wave spectrum

Linear spin-wave theory accurately fits the data

Abstract

We have measured the low-temperature specific heat of the geometrically frustrated pyrochlore Heisenberg antiferromagnet Gd2Sn2O7 in zero magnetic field. The specific heat is found to drop exponentially below approximately 350 mK. This provides evidence for a gapped spin-wave spectrum due to an anisotropy resulting from single ion effects and long-range dipolar interactions. The data are well fitted by linear spin-wave theory, ruling out unconventional low energy magnetic excitations in this system, and allowing a determination of the pertinent exchange interactions in this material.