Observation of Spin Glass Dynamics in Dilute LiHo$_x$Y$_{1-x}$F$_4$

TL;DR

This study presents AC susceptibility measurements on dilute LiHo$_x$Y$_{1-x}$F$_4$, revealing spin glass behavior with a transition temperature around 42.6 mK, characterized by glassy relaxation and broadening spectra.

Contribution

It provides experimental evidence of spin glass dynamics in dilute LiHo$_x$Y$_{1-x}$F$_4$, including a precise transition temperature and critical exponent, clarifying its magnetic phase behavior.

Findings

Spin glass transition at approximately 42.6 mK.

Broadening of absorption spectrum with decreasing temperature.

Characteristic glassy relaxation observed in susceptibility measurements.

Abstract

AC susceptibility measurements are presented on the dilute, dipolar coupled, Ising magnet LiHo$_x$Y$_{1-x}$F$_4$ for a concentration $x = 0.045$. The frequency and temperature dependences of the susceptibility show characteristic glassy relaxation. The absorption spectrum is found to broaden with decreasing temperature suggesting that the material is behaving as a spin glass and not as an exotic spin liquid as was previously observed. A dynamical scaling analysis suggests a spin glass transition temperature of 42.6 mK $\pm 2$ mK with an exponent $z\nu = 7.8 \pm 0.23$.