Fictive Phonons and the Isotope Effect YBa sub 2 Cu sub 3 O sub (7-x).
01 January 1988
The isotope effect on the superconducting transition temperature T sub c (obtained by partial replacement of sup (16) O by sup (18) O) is observed to be a small fraction of the value predicted by weak-coupling theory with complete replacement. Strong-coupling corrections as well as site-selective replacement bring complete agreement between theory and experiment.