CRITICAL-TEMPERATURES OF THE DILUTED SPIN-1 2 ISING SYSTEM WITH GAUSSIAN-TYPE EXCHANGE INTEGRALS/

The site- and bond-disordered spin-1/2 Ising ferromagnetic system is s tudied in which tile exchange integral between nearest-neighbour sites is expressed by the Gaussian probability distribution function. The g eneral expression of the magnetization is derived. The critical temper atures of the system are calculated as functions of concentration and disorder parameter, using the improved correlated effective field theo ry. For comparison, the corresponding results for tile Handrich-Kaneyo shi type probability distribution function of tile exchange integral a re also given. It is shown that tile Gaussian probability function of the exchange integrals gives more reasonable results.