Influence of Dzyaloshinsky-Moriya interactions on the critical behaviour of metallic spin-glasses

Abstract

In this paper, we present non-linear magnetization measurements as a function of field at different temperatures T ≽ Tg for CuMn 0.2 % and AgMn 0.5 %, alloys doped with various amounts of gold impurities in order to change the anisotropy of the systems. We show that one has to consider anisotropy as a relevant scaling parameter in order to obtain a complete coherent description of the critical behaviour of these systems. In particular we can define a set of Ising critical exponents in the range of small fields and temperatures near Tg and a set of Heisenberg exponents in the range of high fields and temperatures far from Tg. The values of the field and temperature characteristic of the occurrence of the crossover between the two regimes both increase as a function of anisotropy; this increase involves power laws from which we determine the exponents