Magnetic ordering in La2Cu2O5

Muon Spin relaxation (mu SR) measurements were carried out on La2Cu2O5, which is a candidate for the spin 1/2 4-leg Heisenberg antiferromagnetic ladder system. At room temperature, the mu SR spectrum can be fitted with the static Gaussian Kubo-Toyabe function. This spectrum originates from static nuclear dipole fields of copper. At similar to 140 K, a sudden decrease of the initial asymmetry was observed. This suggests that a long-range magnetic ordering of the Cu2+ spins occurs due to nonnegligible interladder interactions. (C) 2000 Elsevier Science B.V, All rights reserved.