Long-range magnetic ordering in the spin ladder compound LaCuO2.5probed by muon-spin relaxation

Abstract
A clear sign of long-range magnetic ordering has been observed by muon-spin rotation/relaxation in the two-leg spin-ladder compound LaCuO0.25 below 125 K with a relatively large hyperfine field (∼0.1 T). This result demonstrates that the ground state of the undoped LaCuO2.5 is a magnetically ordered state, rather than the predicted quantum spin-liquid state.