X-ray Fluorescence Spectroscopic Studies of High T_eSuperconductors

Abstract

The Cu-Lβ/Cu-Lα x-ray emission intensity ratio of the following compounds have been found to show an interesting consistency: Cu, Cu₂O, CuO, La_1.85Ba_.15CuO₄ (vacuum annealed), La_1.85Ba_.15CuO₄ (air annealed, T_C = 26K), La_1.85Sr_.15CuO₄ (T_C = 35K), YBa₂Cu₃O_7-Δ (T_C = 91K), ErBa₂Cu₃O_7-Δ (T_C = 81K), and La₂CuO₄. The interesting consistency is that all of the last six compounds, all superconductors or superconductor related, have the same Lβ/Lα intensity ratio, namely, 0.33±0.01. The Cu-Lα,β spectra of CuO, air and vacuum annealed La_1.85 Ba_.15CuO₄ and YBa₂Cu₃O_7-Δ are presented. Also presented are O-K x-ray fluorescence spectra of air and vacuum annealed La_1.85 Ba_.15CuO₄, and of “new” and “old” YBa₂Cu₃O_7-Δwhich seem to show a correspondence between spectral sharpness and high T_C behavior.

Key Words:

• x-ray fluorescence spectroscopy
• Cu Lβ/Lα intensity ratio
• O-K spectrum
• superconductors