Spin Anisotropy and Slow Dynamics in Spin Glasses

TL;DR

This study investigates how spin anisotropy affects aging and memory effects in spin glasses, revealing a continuous decrease in memory sharpness with increased anisotropy and establishing a unified model for coherence length growth across different spin glass types.

Contribution

It provides the first quantitative comparison of memory effects in various spin glasses and introduces a unified model for coherence length growth considering anisotropy.

Findings

Memory effect sharpness decreases with spin anisotropy

Coherence length growth can be modeled uniformly across spin glass types

Magnetic field change experiments determine coherence length in Ising spin glasses

Abstract

We report on an extensive study of the influence of spin anisotropy on spin glass aging dynamics. New temperature cycle experiments allow us to compare quantitatively the memory effect in four Heisenberg spin glasses with various degrees of random anisotropy and one Ising spin glass. The sharpness of the memory effect appears to decrease continuously with the spin anisotropy. Besides, the spin glass coherence length is determined by magnetic field change experiments for the first time in the Ising sample. For three representative samples, from Heisenberg to Ising spin glasses, we can consistently account for both sets of experiments (temperature cycle and magnetic field change) using a single expression for the growth of the coherence length with time.