Magnetization of charge-ordered La2−xSrxNiO4+δ

Abstract We report magnetization measurements on La 2− x Sr x NiO 4+ δ single crystals, with 0⩽ x ⩽0.5. Glassy behaviour associated with the formation of spin-charge stripes, and a separate spin-glass phase at low temperatures were observed. We have also found a ‘memory effect’ in the magnetic field–temperature history, which is found to be suppressed in the low-temperature spin state of the x =0.333 crystal.