On the random transverse field mixed spin Ising model of spin-1/2 and spin-1

The critical behavior of mixed spin Ising model is investigated when the transverse fields are randomly distributed. The calculation shows that when the transverse fields are both bimodally distributed, the transition temperature decreases with increasing transverse field and eventually vanishes at a finite field. When one of the transverse fields is bimodally and the other trimodally distributed, the temperature decreases but does not vanish. When both transverse fields are trimodally distributed, the transverse field dependence of temperature breaks off and a tricritical point appears due to the interaction between quantum fluctuations and disorder.