Thin film composites of YBa2Cu3O7 (YBCO) with gold were deposited by invert
ed cylindrical magnetron sputtering on SrTiO3 (STO), MgO, and yttrium stabi
lized zirconium (YSZ) substrates using a bilayer deposition process. The ma
terial and electrical properties of crystal structure, surface morphology,
resistivity, transition temperature (T-c), resistance ratio, and critical c
urrent (I-c) as a function of temperature and small magnetic fields were in
vestigated. Films deposited on STO showed little degradation in superconduc
ting properties up to 500 Angstrom of gold with 1 k Angstrom of YBCO; for Y
SZ and MgO, the films showed a rapid fall-off in T-c with gold thickness. F
or YSZ 3-10 Angstrom of gold caused the films to become insulating; however
, for gold greater than 25 Angstrom, the films were superconducting but T-c
rapidly fell to zero by 500 Angstrom of gold. Composites on MgO showed the
most rapid fall-off in T-c going to zero by 200 Angstrom of gold. The temp
erature dependence of I-c was predominately quadratic. However, some films
showed a crossover between quadratic and linear temperature dependence in I
-c. The I-c of all the composites showed a response to small magnetic field
s with the films on STO being the least sensitive and those on MgO the most
. There was a trade-off between T-c and field response with the film having
the greatest response having the lowest T-c. These composite films show po
tential for vortex flow device development. (C) 1999 Published by Elsevier
Science B.V. All rights reserved.