J. Phys. IV France 7 (1997) C2-1177-C2-1178
Altered Sr Atomic Environment in La2-xSrxCuO4D. Haskel and E.A. Stern
Department of Physics, Box 351560, University of Washington, Seattle, WA 98195, U.S.A.
The Sr local atomic environment in the high Tc superconductor La2-xSrxCuO4 was probed by polarized XAFS measurements at the Sr K-edge on oriented powder samples with x = 0.075,0.l at T=20K. We confirmed that Sr indeed substitutes at the La site in this compound, but alters the first neighbor oxygen environment. This was found by determining the location of the neighboring metal atoms up to the fifth shell distances through fitting the Sr XAFS, and comparing with La K-edge polarized XAFS in the same samples and with diffraction results. The significant distortions in the immediate oxygen environment of the Sr atoms can be an important factor contributing to the mechanism of the structural and high Tc phase transitions in these cuprates.
© EDP Sciences 1997