EXCITATION OF AN X-RAY STANDING-WAVE IN A SMBA2CU3O7-DELTA THIN-FILM

An X-ray standing-wave was generated by a 150 nm-thick SmBa2Cu3O7-delt a film grown on a SrTiO3(001) substrate by pulsed laser deposition. Th e Sm-L-fluorescence yield was measured as a function of incidence angl e within the range of the (005) reflection from the thin film. The mod ulation of the yield indicated that for this particular epilayer the S m is occupying the rare earth position (no occupation of Basites withi n the limit of error of approximate to 10%). Within the Bragg-reflecti on range, the modulation of the fluorescence yield is only a few perce nt. However, because the crystal is very thin, the reflection curve is rather wide (tenth of a degree) in angle. Employing brilliant synchro tron radiation this approach may be used routinely for structural stud ies of compound materials which are available as high-quality thin fil ms but not as perfect single crystals. (C) 1997 Elsevier Science Ltd.