We have performed both ac susceptibility and dc magnetization measurements on the diluted magnetic semiconductor ${\mathrm{Zn}}_{1-x}{\mathrm{Mn}}_x\mathrm{Te}.$ The measurements clearly indicate spin-glass behavior. For samples with concentrations $x=0.51\mathrm{}$ and $x=0.41,$ the data for the imaginary part of the complex susceptibility $\left({\chi }^{″}\right)$ were analyzed according to conventional power-law dynamics and good scaling was obtained with the critical exponent values $z\nu =10\mathrm{}\pm 2$ and $\beta =1.0\mathrm{}\pm \mathrm{0.2.}$ These values of $z\nu$ and β are consistent with results obtained in other insulating spin-glass systems with short-range interactions. Because of the presence of significant Dzyaloshinsky-Moriya anisotropy in these materials, an attempt was also made to fit the data using an activated dynamics model. However, the scaling of the ${\mathrm{\chi }}^{\mathrm{″}}$ data was less satisfactory in this case. Magnetization measurements on the $x=0.51\mathrm{}$ sample also showed a spin-glass-like transition. Scaling of the nonlinear magnetization just above the transition gave $T_c=20.8\mathrm{}\pm 0.2$ K, and the critical exponent values $\gamma =4.0\mathrm{}\pm 1.0$ and $\beta =0.8\mathrm{}\pm \mathrm{0.2.}$ The value of $T_c$ obtained from the static magnetization measurements is in good agreement with the value $T_c=20.7\mathrm{}\pm 0.05$ K obtained from the dynamic scaling analysis. Further, the value for the critical exponent γ obtained in this work is in fair agreement with values reported for other spin-glass materials. These results represent convincing evidence that diluted magnetic semiconductors are a subset of the class of insulating spin-glass materials with short-range interactions.

• Received 29 June 1998

DOI:https://doi.org/10.1103/PhysRevB.58.12876