Crossover from Heisenberg to Ising spin-glass-like magnetic properties in random anisotropy magnets amorphous Dy16MxFe84 − x (M Cu, Al, Cu and Al)

We investigated how the Heisenberg spin-glass (SG)-like critical lines in the DC field (H)-temperature plane for a weak random anisotropy magnet with a small ratio of local random anisotropy to exchange constant, D/J, change to Ising-like critical lines by substituting Cu and Al for Fe in a-Dy16Fe84; we found that when D/J is increased by the substitution, the difference in critical lines becomes obscure, which critical lines were determined by the transverse and longitudinal AC susceptibilities in H and by temperature dependence of the magnetization. It indicates that Ising SG-like behavior appears even if D/J changes from about 0.07 to about 0.1.