Anisotropic phase diagram and spin fluctuations of the hyperkagome magnet Gd3Ga5O12 as revealed by sound velocity measurements

TL;DR

This study uses sound velocity measurements to explore the anisotropic phase diagram and spin fluctuations in Gd3Ga5O12, revealing multiple ordered phases, lattice softening linked to spin fluctuations, and evidence of a spin gap within the spin liquid phase.

Contribution

It provides detailed insights into the anisotropic magnetic phases and spin dynamics of Gd3Ga5O12 through acoustic measurements, highlighting the presence of a spin gap and complex phase behavior.

Findings

Highly anisotropic phase diagram with different ordered phases for H||[110] and H||[100]

Lattice softening associated with spin fluctuations at low fields

Evidence of a spin gap within the spin liquid phase

Abstract

Sound velocity and attenuation measurements on the frustrated garnet material Gd3Ga5O12 (GGG) are presented as a function of field and temperature, using two different acoustic modes and with two different magnetic field orientations: [100] and [110]. We demonstrate that the phase diagram is highly anisotropic, with two distinct field-induced ordered phases for H||[110] and only one for H||[100]. Extensive lattice softening is found to occur at low fields, which can be associated with spin fluctuations. However, deep within the spin liquid phase a low-temperature stiffening of the lattice and reduced attenuation provides evidence for a spin gap which may be related to short-range antiferromagnetic correlations over minimal 10-spin loops.