Title :
An experimental study of high Tc superconducting microstrip transmission lines at 35 GHz and the effect of film morphology
Author :
Chorey, C.M. ; Bhasin, K.B. ; Warner, J.D. ; Josefowicz, J.Y. ; Rensch, D.B. ; Nieh, C.W.
Author_Institution :
Sverdrup Technol., Brook Park, OH, USA
fDate :
3/1/1991 12:00:00 AM
Abstract :
Microstrip transmission lines in the form of ring resonators have been fabricated from a number of in-situ grown laser-ablated films and postannealed cosputtered YBa2Cu3O7-x (YBCO) films. The properties of these resonators have been measured at 35 GHz, and the observed performance is examined in light of the critical temperature (Tc), film thickness, and the film morphology, which is different for the two deposition techniques. It is found that Tc is a major indicator of the film performance for each growth type, with film thickness becoming important as it decreases towards 1000 Å. It is also found that the films with a mixed grain orientation (both a-axis and c-axis oriented grains) have poorer microwave properties as compared with the primarily c axis oriented material. It is speculated that this is due to the significant number of grain boundaries between the different crystallites, which may act as superconducting weak links and contribute to the surface resistance
Keywords :
barium compounds; grain boundaries; high-temperature superconductors; resonators; solid-state microwave devices; sputtered coatings; strip line components; strip lines; superconducting thin films; superconducting transition temperature; vapour deposited coatings; yttrium compounds; 35 GHz; EHF; MM-wave type; YBa2Cu3O7-x; a-axis; c-axis oriented grains; critical temperature; deposition techniques; film morphology; film performance; film thickness; grain boundaries; high temperature superconductors; in-situ grown laser-ablated films; microwave properties; millimetre waves; mixed grain orientation; postannealed cosputtered films; ring resonators; superconducting microstrip transmission lines; superconducting weak links; surface resistance; Grain boundaries; Microstrip resonators; Optical ring resonators; Ring lasers; Superconducting transmission lines; Surface resistance; Temperature; Thickness measurement; Transmission line measurements; Yttrium barium copper oxide;
Journal_Title :
Magnetics, IEEE Transactions on
