J.-C. Lin, P. L. Taylor, and R. Rangel, Physical Review E 47, 981 (1993)

Ferromagnetic phase transition in random Potts spin chains

We study the ferromagnetic phase transition in a model consisting of one-dimensional three-state Potts spin chains with random intrachain couplings and comparatively weak ferromagnetic interchain couplings. Mean-field theory is employed to decouple approximately the interchain couplings. The transfer-matrix method is then used to study the resulting effectively one-dimensional random-bond Potts model. The free energy as a function of the ferromagnetic order is calculated numerically and a first-order ferromagnetic-paramagnetic phase transition is found over a wide range of degree of randomness.