Spin State Transitions in RECoO3 Investigated by μ+SR

The spin-state of RECoO3(RE = La, Pr, Nd, and PrxLa1−x)has been investigated by μ+SR experiments. In particular, the muonic Knight shift in a high TF of 10 kOe was studied at temperatures below 300 K. By combining these measurements with the dc-susceptibility data, the spin-state transition temperature(TSS)was found to increase monotonically as the average ionic radius of the RE ion is decreased. Our measurements demonstrate that TF-μ+SR is a unique technique to detect the spin-state transition in compounds regardless of coexistence of large magnetic moments through the change in microscopic magnetic environments at TSS.