Elastic anomalies induced by spin-flop in La1.88Sr0.12CuO4

Temperature dependence of the velocity V-s and the attenuation of the ultrasonic waves are measured to investigate the relation between the spin type of magnetic order and lattice instability of the low-temperature tetragonal phase in La2 - xSrxCuO4 (x - 1/8). In the field above 8 T along the [0 1 0] direction of the orthorhombic notation, a significant increase of V-s in the c(44) mode is observed below similar to 15 K where spin-flop occurs. This gigantic increase of V-s suggests that the structural transformation from the orthorhombic to the low-temperature tetragonal phase is induced by the spin-flop. (C) 2000 Elsevier Science B.V. All rights reserved.