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

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 one to determine the critical exponents $\ensuremath{\beta}=0.03\ifmmode\pm\else\textpm\fi{}0.01$ and $\ensuremath{\beta}\ensuremath{\delta}=0.4\ifmmode\pm\else\textpm\fi{}0.1,$ which coincide with those reported recently in a different system, thus supporting the existence of universality for disorder-induced critical points.