Low-field susceptibility of GdAl spin glass: Cooling-rate dependence and field dependence of peak temperature

Abstract

We use SQUID magnetometry to extend dc susceptibility measurements on GdAl spin glasses to 10 mOe, two orders of magnitude lower than previously reported. We confirm that if the temperature is lowered too quickly, a nonequilibrium susceptibility may be observed, but for sufficiently slow cooling, an equilibrium, erogodic susceptibility may be determined down to a few degrees below the susceptibility peak. The field dependence of this peak is incompatible with a T=0 phase transition model but supports a finite temperature-phase transition.