Experimental arguments for a non-zero transition temperature in RKKY Heisenberg spin glasses without anisotropy

Abstract
While the existence of a phase transition at finite Tc is well admitted for Ising spin glasses in 3-dimensions, recent theoretical studies have proposed that T c is zero in Heisenberg spin glasses and that the finite T c of real systems is induced by the anisotropy. To clear up this question, we analyse the influence of the anisotropy on the critical behaviour and the transition temperature of CuMn and AgMn alloys doped with Au or Pt. This analysis rather suggests a finite Tc for RKKY Heisenberg spin glasses in the limit of zero anisotropy