Magnetism of oxygen deficient perovskite La8-xSrxCu8O20

We have measured muon spin relaxation (mu SR) of La8-xSrxCu8O20, an oxygen deficient perovskite, across two magnetic phase transitions at T = T-c1 and T-c2. Static magnetic order was observed below T similar to 140 K, where w eak ferromagnetism appears in magnetization measurements (T-c1). No signifi cant change appeared in the mu SR static field width at the lower transitio n temperature T-c2, where an anomaly is seen in the Hall coefficient. The s tatic magnetism thus originates from localized spins presumably in the one- dimensional Cu-O chains. (C) 2000 Elsevier Science B.V. All rights reserved .