Disorder induced critical phenomena in magnetically glassy Cu-Al-Mn alloys

TL;DR

This study investigates how disorder affects phase transitions in Cu-Al-Mn alloys by analyzing magnetic hysteresis, revealing a disorder-induced critical point with specific critical exponents.

Contribution

It provides experimental evidence of a disorder-induced phase transition in magnetic alloys and determines critical exponents consistent with theoretical predictions.

Findings

Discontinuous magnetization below a critical temperature.

Identification of a disorder-induced phase transition line.

Critical exponents β=0.03±0.01 and βδ=0.4±0.1.

Abstract

Measurements of magnetic hysteresis loops in Cu-Al-Mn alloys of different Mn content at low temperatures are presented. The loops are smooth and continuous above a certain temperature, but exhibit a magnetization discontinuity below that temperature. Scaling analysis suggest that this system displays a disorder induced phase transition line. Measurements allow to determine the critical exponents $\beta=0.03\pm 0.01$ and $\beta \delta = 0.4 \pm 0.1$ in agreement with those reported recently [Berger et al., Phys. Rev. Lett. {\bf 85}, 4176 (2000)]