Dynamic susceptibility measurements at the spin-glass transition in the Zn1−xMnxIn2Se4 semiconductor

Measurements of the magnetic properties of the magnetic semiconductor Zn1?xMnxIn2Se4 for two Mn compositions (x = 0.87 and 1.00) are presented in this work. The localized Mn ions in the layered rhombohedral structure undergo a spin-freezing transition below 3.5?K. The frequency-dependent freezing temperature Tf varies as ?Tf/(Tf?log?)?0.022, indicating a spin-glass behaviour. From the frequency dependence of Tf, the validity of the critical slowing down associated with a true phase transition is tested. For T>Tc, the dynamic scaling of the imaginary component of ac susceptibility data yields the following set of critical parameters: z? = 9.7 ? 1.0, ? = 1.18 ? 0.20 and Tc = 2.61 ? 0.06?K for x = 0.87 and z? = 10.7 ? 0.9, ? = 1.20 ? 0.20 and Tc = 3.43 ? 0.01?K for x = 1.00. These values are in good agreement with reported values for other spin glasses.