The static nonlinear magnetization $M_S$ of the insulating spin glass ${\mathrm{Cd}}_{0.6}$${\mathrm{Mn}}_{0.4}$Te has been studied in the vicinity of its freezing temperature $T_C$, in weak magnetic fields H ranging from 0.1 to 55 Oe. The divergence of the nonlinear magnetization above $T_C$ is well described by the scaling function $M_S$(t,H)=$t^{(\gamma +3\mathrm{}\beta )/2\mathrm{}}$F (H/$t^{(\gamma +\beta )/2\mathrm{}}$) with critical exponents γ=3.3±0.3 and β=0.9±0.2, as expected for usual three-dimensional (3D) Heisenberg spin glasses. The corresponding value deduced for $T_C$=12.37±0.05 K agrees well with its determination from dynamic measurements. Our result proves that disordered 3D Heisenberg frustrated antiferromagnets exhibit a paramagnetic to spin-glass transition at finite temperature.

• Received 10 April 1989

DOI:https://doi.org/10.1103/PhysRevB.40.862