MONTE-CARLO SIMULATION OF STRONGLY DISORDERED ISING-FERROMAGNETS

We report about extensive Monte Carlo simulations of disordered Ising systems with concentrations of magnetic sites between p = 1.0 and p = 0.5. We have measured the magnetization, the susceptibility and the caloric properties in the critical region. In addition the magnetization-energy correlation function has been investigated and the critical exponent 1-/S = (a + y)/2 has been determined. We find that power law behaviour and scaling is fulfilled in the whole concentration range. The effective critical exponents y, £ and C are shown to be concentration dependent. In the range of strong disorder y and j9 increase until they reach a kind of asymptotic behaviour at £ = 0.336 ± 0.01 and y »1.49 ± 0.02 for p - 0.6. In accord with the exponent relation C -1 the critical exponent C decreases with dilution to C-0.675 ±0.01. © 1990 IOP Publishing Ltd.