CRITICAL-DYNAMICS OF SLIGHTLY DISORDERED SPIN SYSTEMS

This paper is a field theoretic description of the critical dynamics o f spin systems with frozen nonmagnetic impurities. For three-dimension al systems the dynamical critical exponent is found directly by employ ing the three-loop approximation with the Pade'-Borel summation techni que. The results are compared with those obtained by calculating the d ynamical exponent for homogeneous systems in the four-loop approximati on, and with the values obtained by computer simulation of the critica l dynamics by Monte Carlo methods. Calculations of the dynamical expon ent for the two-dimensional Ising model in the four-loop approximation are also presented. (C) 1998 American Institute of Physics. [S1063-77 61(98)01509-1].