Magnetoelastic anomalies at spontaneous and field-induced transitions in La1-xSrxMnO3

Thermal expansion Delta l/l(T) and longitudinal and transverse magnetostric tion lambda(parallel to,perpendicular to)(H, T) in pulsed magnetic fields H up to 250 kOe were studied in single La1-xSrxMnO3 crystals (x = 0.1, 0.125 and 0.15). A strong increase of the field-induced magnetostriction lambda( parallel to,perpendicular to)(H) (from 10-4 up to 7 x 10(-4)) was observed in the Jahn-Teller distorted O' phase as compared to the charge-ordered and pseudocubic ones, which was accompanied by additional features in the vici nity of the spontaneous transitions. The results may be related to a suppre ssion of the O' phase and field-induced transitions to a new orbital-ordere d ferromagnetic state. (C) 2000 Elsevier Science B.V. All rights reserved.