Ordering in a spin glass under applied magnetic field

TL;DR

This study investigates the behavior of a AuFe spin glass under high magnetic fields, revealing that its ordered state persists contrary to some theoretical predictions, and its phase diagram resembles mean field models with replica symmetry breaking.

Contribution

It provides experimental evidence that a Heisenberg spin glass maintains its ordered state under high magnetic fields, challenging droplet model predictions.

Findings

Spin glass order survives high magnetic fields

Presence of transverse and longitudinal irreversibility lines

Phase diagram resembles mean field models with replica symmetry breaking

Abstract

Torque, torque relaxation, and magnetization measurements on a AuFe spin glass sample are reported. The experiments carried out up to 7 T show a transverse irreversibility line in the (H,T) plane up to high applied fields, and a distinct strong longitudinal irreversibility line at lower fields. The data demonstrate for that this type of sample, a Heisenberg spin glass with moderately strong anisotropy, the spin glass ordered state survives under high applied fields in contrast to predictions of certain "droplet" type scaling models. The overall phase diagram closely ressembles those of mean field or chiral models, which both have replica symmetry breaking transitions.