EVIDENCE FOR MN CLUSTERING IN DILUTE CUMN ALLOYS FROM HIGH-FIELD (40T) MAGNETIZATION CURVES AT 4.2-K

Magnetization curves of CuMn alloys with Mn concentration between 1.5 and 10 at.% have been measured at 4.2 K in fields up to 40 T, using a pulsed-field method. The results found for different concentrations can be scaled upon one another, which is a clear indication for the occurance of magnetic clusters. Analysis of this universal curve in terms of Brillouin functions yields the values zIJI/k{reversed tilde equals}-44K, zIIJII/k{reversed tilde equals}-10K and zIIIJIII/k{reversed tilde equals}-0.5K, for the largest three interactions within each cluster. © 1979.