CRITICAL-BEHAVIOR OF THE 3-DIMENSIONAL +/- J MODEL IN A MAGNETIC-FIELD

The three-dimensional +/- J Ising spin glass model is investigated by means of Monte Carlo simulation. In uniform fields of various strength, the Edwards-Anderson susceptibility chi(EA) is calculated at T = 0.9J which is lower than the transition temperature in the zero-field case. It is found that chi(EA) decreases monotonically when the field strength is increased and that the data do not suggest a phase transition in a finite field. The best parameters for the scaling function of the form chi(EA)(H) congruent-to l(psi)chi(EA)((H-H(c))l(-phi)) are estimated to be H(c) = 0.00(10)J, psi= 2.16(22) and phi = -1.13(6). These results support the hypothesis that the phase transition does not exist in a finite magnetic field.