Phase-Transition Behavior in a Random-Anisotropy System

The character of the magnetic transition is studied for a magnetic glass with strong random-anisotropy and ferromagnetic interactions. Field-dependent ac susceptibility measurements are presented near the ordering temperature of ${\mathrm{Tb}}_{64}$ ${\mathrm{Fe}}_{20}$ ${\mathrm{Ga}}_{16}$. The data are analyzed with a scaling theory for the singular susceptibility. An excellent collapse of the $H$, $T$ data is obtained for reduced temperatures in the range 0.002-0.13. These results, which are compared with recent theoretical work, provide strong evidence for a true phase transition in a random-anisotropy system.