Micro-PIXE and channeling PIXE analysis of Ag-doped YBa2Cu3O7-delta thin

Nuclear Microscopy, utilizing a 2 MeV He+ beam for channeling Rutherford Ba ckscattering (RBS) and PIXE analysis, was used to characterise Ag-doped YBa 2Cu3O7-delta thin films and measure the lateral distribution of the Ag. The samples were prepared by in situ two-beam pulsed laser deposition in order to investigate the effects of such dopings on critical current densities [ 1,2]. Films deposited at temperatures above 650 degrees C form needle-like surface structures with a length of up to 100 mu m; these tend to align wit h in-plane a-b axis. Results for a sample prepared at a substrate temperatu re of 730 degrees C and a maximum Ag concentration of 5 at.% are discussed. The needle-like structures were found to be rich in Ag and Cu, and the YBa 2Cu3O7-delta film contained 0.02 at.% Ag. Broad beam PIXE-channeling result s indicate that 19% of the Ag is substitutional. (C) 1999 Elsevier Science B.V. All rights reserved.