Measurement of diffusion coefficients of Ag in YBa2Cu 3O7 by the EDXRF technique

Abstract

The diffusion of Ag in superconducting YBa2Cu3O 7 ceramic was studied over the temperature range 700-850°C by the energy-dispersive X-ray fluorescence (EDXRF) technique. For the excitation of silver atoms, an annular Am-241 radioisotope source (50 mCi) emitting 59.543 keV photons was used. The temperature dependences of Ag diffusion coefficients in grains (D1) and over the grain boundaries (D2) are described by the equations D1 = 1.4 × 10-2 exp[-(1.18 ± 0.10)/kT] and D2 = 3.1 × 10-4 exp[-(0.87 ± 0.10)/kT]. Copyright © 2003 John Wiley & Sons, Ltd.