MAGNETIC SPECIFIC-HEAT AND CRITICAL MAGNETIC-SUSCEPTIBILITY OF THE DILUTED ANTIFERROMAGNET COPMG1-PO

For CopMg1-pO, a prototype randomly diluted fcc antiferromagnet, measu rements of the specific heat versus temperature show that the size of the lambda anomaly at T(N) decreases as p decreases. These results sho w that with increasing dilution, a progressively larger fraction of th e magnetic entropy is removed by short-range order processes. The crit ical susceptibility chi(c) at T(N) increases as p decreases, supportin g the idea that near Mg sites, the balance of the two antiferromagneti c sublattices is destroyed. After correcting for single ion contributi on, chi(c)(p)/chi(c)(1) is found to vary as (p-p(c))-tau for p < 0.47 (p(c) = 0. 136). The experimental value of tau almost-equal-to 0.7 is in reasonable agreement with the numerical estimate Of tau = 0.5 +/- 0 .2 by Harris et al. for cubic systems.