Channeling studies of YBaCuO thin films with combined RBS and PIXE

Abstract

Thin films of YBa 2Cu 3O 7− x (YBCO) deposited by hollow cathode discharge sputtering on (100) MgO, (100) SrTiO 3 and (100) Zr(Y)O 2 (YSZ) buffered r-plane sapphire, are studied using channeling techniques. Simultaneous Rutherford backscattering spectrometry (RBS) and particle induced X-ray emission (PIXE) are applied to investigate the high- T c superconducting films (HTSC) and the pure substrates. Using the RBS signal of Ba near the surface, we obtain minimum yields of 3.2%, 17% and 18% for films on MgO, SrTiO 3 and Zr(Y)O 2 substrates respectively. The minimum yields measured on thin films with PIXE depend on the film thickness, since X-rays from the total depth of the film are integrated. For the films investigated, minimum yields in the range 12–40% are measured when Ba L, Y L, Y Kα and Cu Kα X-rays are detected. A constant half-angle for 〈100〉 axial scans was found for RBS and PIXE measurements on all YBCO samples when signals from Ba, Y and Cu were used. Results on the homogeneity of a large area deposition (50 × 50 mm 2) are presented. The present channeling results are compared with T c, and j c measurements.