Ising-cluster excitations in Rb2Co Mg1−F4 near percolation threshold

Abstract Complex susceptibility measurements have been carried out on a diluted square lattice antiferromagnet of Ising spins, Rb 2 Co c Mg 1− c F 4 ( c p =0.593) to elucidate the magnetic anomaly probed by μSR. The temperature dependence of the median correlation time deduced by the Cole–Cole plot indicates that the anomaly of μSR is caused by the slowing-down of Ising-cluster excitations associated with development of two-dimensional short range order.