Spin dynamics of the director state in frustrated hyperkagome systems

TL;DR

This study investigates the magnetic structure and dynamics of frustrated hyperkagome compounds Gd3Ga5O12 and Gd3Al5O12, revealing complex magnetic correlations, low-energy excitations, and differences in low-frequency dynamics.

Contribution

It demonstrates the presence of similar multipolar director correlations in Gd3Al5O12 as in Gd3Ga5O12, highlighting the ubiquity of these structures in hyperkagome systems.

Findings

Existence of multipolar director correlations in Gd3Al5O12

Observation of low-energy magnetic excitations related to the director state

Detection of spin diffusion and differing low-frequency dynamics

Abstract

We present an experimental study of the magnetic structure and dynamics of two frustrated hyperkagome compounds, Gd3Ga5O12 and Gd3Al5O12. It has previously been shown that Gd3Ga5O12 exhibits long-range correlations of multipolar directors, that are formed from antiferromagnetic spins on loops of ten ions. Using neutron diffraction and Reverse Monte Carlo simulations we prove the existence of similar magnetic correlations in Gd3Al5O12, showing the ubiquity of these complex structures in frustrated hyperkagome materials. Using inelastic neutron scattering we shed further light on the director state and the associated low lying magnetic excitations. In addition we have measured quasielastic dynamics that show evidence of spin diffusion. Finally, we present AC susceptibility measurements on both Gd3Ga5O12 and Gd3Al5O12, revealing a large difference in the low frequency dynamics between the two otherwise similar compounds.