Microwave Resonators Made of Superconductors with High Kinetic Inductance Material

Development of hybrid circuits that combine conventional Al-based Josephson junctions with high-kinetic-inductance elements will facilitate implementation of protected superconducting qubits [1]. We report on microwave characterization of coplanar half-wavelength microwave resonators fabricated from highly disordered films of Aluminum. The film resistance was studied as a function of the Oxygen partial pressure. The kinetic inductance for the films with a sheet resistance of 0.5-1 kOhm was obtained from the resonance frequency. In the talk we will compare the kinetic inductance data with the estimates based on the Mattis-Bardeen theory developed for weakly disordered superconductors. The observed values of the intrinsic quality factor in excess of 100,000 make disordered Al films a promising candidate for low-loss high-kinetic-inductance elements of quantum circuits.
1. M. T. Bell et al., Phys. Rev. Lett. 116, 107002 (2016).