Measurement of the oxygen content in high-Tcsuperconductors: Enhanced resonant ion-scattering analysis

Abstract

A simple and accurate method is demonstrated to measure oxygen concentrations in thin films of $R_1{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ (1:2:3 phase, where $R$ stands for the rare-earth element) by ion-beam analysis. Enhanced ion-scattering cross sections for 2.5-MeV protons and 8.7-MeV alpha particles, with depth resolutions of 200 and 50 nm, respectively, have been used to determine the oxygen content of laterally uniform thin-film and bulk superconductors. Both the H and He ion-beam analysis techniques are demonstrated to have the needed accuracy ($\Delta \delta =0.3\mathrm{}$) to ensure the proper composition for high-temperature superconductors in the 1:2:3 phase. These two techniques are based on enhanced ion-scattering cross section ($\sigma$) for which the ratios of $\sigma$ to the Rutherford cross sections are 5 for 2.5-MeV protons, and 22 for 8.7-MeV alpha particles.