Title :
Off-axis co-sputtered YBCO and CeO/sub 2/ thin films
Author :
Cukauskas, E.J. ; Allen, L.H. ; Pond, J.
Author_Institution :
Naval Res. Lab., Washington, DC, USA
fDate :
6/1/1997 12:00:00 AM
Abstract :
We have investigated the properties of off-axis co-sputtered films of YBCO and CeO/sub 2/ having CeO/sub 2/ concentrations up to 43%. Morphology investigations suggest that films with more than 29% CeO/sub 2/ may consist of a new material phase, T/sub c/ and resistance ratio decreased with increasing CeO/sub 2/ concentration. Degradation of T/sub c/, after photoresist processing the films was observed and reversed by a 20 minute oxygen plasma etch. The temperature dependence of the critical current near T/sub c/ showed two power law dependence regions with a crossover near 0.99 T/sub c/ for films having low concentrations of CeO/sub 2/. I/sub C/ ´s were decreased by small applied magnetic fields, and for some samples the response was observed to increase at lower temperature. For a sample having 26% CeO/sub 2/, a 40% reduction in critical current was observed for a 2 Gauss applied field. This response indicates that this may be a candidate material for the development of Josephson vortex flow devices.
Keywords :
Josephson effect; barium compounds; cerium compounds; critical current density (superconductivity); crystal morphology; flux flow; high-temperature superconductors; sputtered coatings; superconducting thin films; superconducting transition temperature; yttrium compounds; 20 min; Josephson vortex flow devices; YBCO/CeO/sub 2/ thin films; YBa/sub 2/Cu/sub 3/O/sub 7/-CeO/sub 2/; critical current; high temperature superconductor; increasing CeO/sub 2/ concentration; morphology; off-axis co-sputtered films; resistance ratio; small applied magnetic fields; temperature dependence; Critical current; Degradation; Etching; Morphology; Plasma applications; Plasma materials processing; Plasma temperature; Resists; Temperature dependence; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
