ARXPS, SEM, and SAM studies of highly textured YBa/sub 2/Cu/sub 3/O/sub x/ films

摘要

The electric conduction in the new cuprate superconductors suffers from intragrain and intergrain weak links. In transition metal oxides weak links show up in a specific chemistry, which can be measured by X-ray photoelectron spectroscopy and by Auger electron spectroscopy. To measure a defective local chemistry, the chemical signature of the reaction cinder has to be identified and the chemical signature of the perfect crystal has to be established. For highly textured cuprate films this has been done successfully, yielding the signature of the reaction cinder, e.g. BaO/sub 2/ or graphite, the signature of the interface reactions, e.g. Ba-aluminate on Al/sub 2/O/sub 3/ or Cu diffusion into MgO, and the signature of c-axis surfaces being a BaO/sub x/ layer on YBa/sub 2/Cu/sub 3/O/sub x/, which results in a 1-nm-thick insulating layer.