Eur. Phys. J. B 14, 661-667 (2000)
https://doi.org/10.1007/s100510051076

Effects of random biquadratic couplings in a spin-1 spin-glass model

¹ Departamento de Ciências Naturais, Universidade Estadual do Rio Grande do Norte, 59610-210 Mossoró - RN, Brazil
² Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Campus Universitário, C.P. 1641, 59072-970 Natal - RN, Brazil

Received: 18 May 1999
Revised: 20 October 1999
Published online: 15 April 2000

Abstract

A spin-1 model, appropriated to study the competition between bilinear (J_ijS_iS_j) and biquadratic (K_ijS²_iS²_j) random interactions, both of them with zero mean, is investigated. The interactions are infinite-ranged and the replica method is employed. Within the replica-symmetric assumption, the system presents two phases, namely, paramagnetic and spin-glass, separated by a continuous transition line. The stability analysis of the replica-symmetric solution yields, besides the usual instability associated with the spin-glass ordering, a new phase due to the random biquadratic couplings between the spins.