Monte Carlo study of the random-exchange-Ising-model behavior in a diluted antiferromagnet:: Fe0.48Zn0.52F2 -: art. no. 092401

We present a microscopic Monte Carlo description of the site-diluted b.c.c. frustrated Ising antiferromagnet FexZn1-xF2, with an emphasis on the random exchange Ising model (REIM) phase observed at high and intermediate magnetic concentrations, 0.3 less than or similar to x < 1.0, in a zero magnetic field. Thermodynamical, microscopic, and critical properties of the x=0.48 system are found to be in good agreement with both zero-field experimental measurements and previous Monte Carlo results on the site-diluted s.c. nonfrustrated ferromagnetic Ising model. In particular, we contrast the results of the REIM behavior at x=0.48 with those of the zero-field spin-glass phase observed at x=0.25.