Critical behavior of the transverse susceptibility in aCuMn spin glass

Transverse ac susceptibility measurements on CuMn4 at.% are used to examine the quantity δ, which is closely related to the transverse order parameter ${\Delta }^y$ introduced by Kotliar and Sompolinsky in a recent Letter. The δ data scale in the critical-phenomena sense, giving strong support for the existence of a phase transition in this weakly anisotropic spin glass. We show that this transition occurs along the Gabay-Toulouse line, as predicted by mean-field theory.