Title :
Microwave Losses in YBCO Coplanar Waveguide Resonators at Low Power and Millikelvin Range
Author :
Arzeo, Marco ; Lombardi, Floriana ; Bauch, Thilo
Author_Institution :
Dept. of Microtechnol. & Nanosci., MC2, Chalmers Univ. of Technol., Goteborg, Sweden
Abstract :
We have investigated the temperature dependence of microwave losses in the low-power limit and millikelvin temperature range of a thin-film YBa2Cu3O7-x (YBCO) λ/2 coplanar waveguide resonator patterned on a (La0.3Sr0.7) (Al0.65Ta0.35)O3 (LSAT) substrate covered by a CeO2 seed layer. The unloaded quality factor is mainly governed by the surface resistance of the YBCO film and the dielectric losses caused by resonant absorption due to a bath of two-level fluctuators in the dielectrics. The value of the unloaded quality factor at 20 mK and low power, i.e., Q0 ≃2000, allows for the realization of YBCO microwave quantum circuits implementing biepitaxial grain-boundary Josephson junctions.
Keywords :
Q-factor; cerium compounds; coplanar waveguides; dielectric losses; lanthanum compounds; microwave circuits; microwave resonators; superconducting junction devices; surface resistance; thermal analysis; thin films; yttrium compounds; (La0.3Sr0.7)(Al0.65Ta0.35)O3; CeO2; YBa2Cu3O7-x; biepitaxial grain-boundary Josephson junctions; dielectric losses; microwave losses; microwave quantum circuits; milliKelvin temperature range; quality factor; resonant absorption; seed layer; surface resistance; temperature 20 mK; temperature dependence; thin-film coplanar waveguide resonator; two-level fluctuators; Dielectric losses; Josephson junctions; Microwave theory and techniques; Superconducting microwave devices; Yttrium barium copper oxide; Dielectric losses; high critical temperature supreconductors; superconducting microwave devices; superconducting thin films; surface resistance; yttrium barium copper oxide (YBCO);
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2014.2364777
