摘要
The longitudinal-random-fieM mixed Ising model consisting of arbitrary spin values has been studied by the use of an effective field theory with correlations （EFT）. The phase diagrams of systems with mixed spins： σ = 1/2, S = 1; σ = 1/2, S = 3/2 are plotted. Not only the discontinuity at T = 0 K, is found when both longitudinal fields are trimodal distributed, but also the trieritical behavior is observed in these phase diagrams between the bimodal and trimodal distributions of longitudinal fields, which is different from the single-spin one. The appearance of tricritical point is independent of the coordination number and spin values.
基金
Supported by the Research Fund of Education Department under Grant No. 2009A305
Science and Technology Department under Grant No. 20061023 in Liaoning Province of China
National Natural Science Foundation of China under Grant No. 10874062
National 211 Development Fund for Key Engineering Program of Liaoning University
Youth Foundation of Liaoning University under Grant No. 2007LDQN03
