CRITICAL-DYNAMICS IN CD1-XMNXTE SPIN-GLASSES

The critical dynamics in Cd1-xMnxTe is investigated by accurate Faraday rotation measurements carried out in the vicinity of the freezing temperature on compounds of composition x=0.38 and x=0.50. The temperature dependence of the average relaxation time is well described by conventional power law, for critical temperatures T(c)=9.9+/-0.1 K (x=0.38) and T(c)=17+/-0.1 K (x=0.50). The validity of the dynamic scaling law for the imaginary part of the complex susceptibility is tested using the chi''(T,omega) data obtained in the entire temperature and frequency range. The best scalings performed for the above T(c) values yield a dynamic exponent znu=9+/-1 and an order-parameter exponent beta=0.6+/-0.1 for both investigated compounds. The observation of a unique scaling function in the composition range 0.3-0.5 supports the existence of universality.