T. Nurgaliev et al., MICROWAVE PROPERTIES OF YBCO THIN-FILMS IN THE WEAKLY COUPLED GRAIN MODEL, Journal of low temperature physics, 106(3-4), 1997, pp. 475-480
Microwave properties of highly oriented thin YBCO films deposited on Y
SZ and LaAlO3 substrates were investigated at 3 GHz and 4.3 GHz using
microstrip resonator technique. The microwave characteristics of the f
ilms on YSZ substrates were close to those of a medium containing weak
links and were interpreted in the coupled grain model approximation.
The YBCO films on LaAlO3 substrates demonstrated very good microwave p
roperties and could be considered at least as samples with ''strong''
weak links. Unloaded e-factor of microstrip resonators prepared from s
uch films and Cu ground plane reached 3000 at 77 K.