Magnetization and ac susceptibility measurements on single crystalline Ga 1−x Mn x S ͑x = 0.09͒ have been measured near the spin-glass transition. No other III-VI diluted magnetic semiconductor ͑DMS͒ is currently known to exhibit a spin-glass transition for comparison with Ga 1−x Mn x S. Both the magnetization and ac susceptibility measurements were analyzed according to the appropriate universal scaling function for spin-glass transitions. The nonlinear magnetization scaled with the critical exponent values ␥ = 4.0Ϯ 1.0 and ␤ = 0.8Ϯ 0.2 for a spin-glass transition temperature T c = 11.2Ϯ 0.2 K. The analysis of the ac susceptibility's out-of-phase component Љ͑ , T͒ yielded the parameter values T c = 10.8Ϯ 0.3 K, z =10Ϯ 1, and ␤ = 0.6Ϯ 0.3. The values of the critical exponents are consistent with those obtained in many DMS and non-DMS insulating spin glasses with different lattice structures and exchange interactions. These results indicate that III-V DMS materials such as Ga 1−x Mn x S belong in the same three-dimensional short-range Heisenberg universality class as other DMS and non-DMS insulating spin glasses.

Magnetic properties of single crystalline Ga1−xMnxS (x=0.09) have been measured near the spin-glass transition. No other III-VI DMS is currently known to exhibit a spin-glass transition for comparison with Ga1−xMnxS. Ga1−xMnxS (Tc=11.2K) shows unexpected similarity to II-VI DMS Zn1−xMnxTe (Tc=20.8K). For both systems, the quantity χnl=−Mnl∕H (where Mnl=Mtotal−Mlinear) diverges as the temperature approaches the spin-glass transition temperature Tc from above. It also increases with applied field at temperatures just above Tc for both systems. The spin-glass transitions in both Ga1−xMnxS and Zn1−xMnxTe follow the same universal scaling function with the same critical exponent values (γ=4.0±1.0 and β=0.8±0.2). The temperature of Ga1−xMnxS’s low-field spin-glass transition cusp was found to occur at 10.9K. As expected, this is slightly lower than the true spin-glass transition temperature Tc=11.2±0.2K obtained from the scaling analysis. The asymptotic, zero-field limit of the spin-glass transition cusp was found to persist at 10.9K up to ∼1T before being suppressed to lower temperatures with increasing field. Questions remain about if Ga1−xMnxS should belong in the same universality class as Zn1−xMnxTe since Ga1−xMnxS is quasi-two-dimensional and Zn1−xMnxTe is three-dimensional.