Fabrication and characterization of magnetic-field-resilient MoRe superconducting coplanar waveguide resonators

Abstract

Magnetic-field-resilient superconducting coplanar waveguide (SCPW) resonators are essential for developing integrated quantum circuits. Molybdenum–Rhenium (MoRe), which is a disordered superconducting alloy forming a highly transparent contact to the graphene and carbon nanotubes, would be a promising platform for realizing the field-resilient SCPW resonators combined with nano-hybrid quantum devices. We fabricated MoRe SCPW resonators and investigated their microwave transmission characteristics with varying temperature and external magnetic field. The thickness of MoRe film is a critical parameter determining the lower critical field, kinetic inductance, and characteristic impedance of the SCPW resonator, resulting in drastic changes in the quality factor and the resonance frequency. We obtained a maximum value of Qi > 104 in parallel magnetic fields up to B|| = 0.15 T for the 27-nm-thick MoRe resonator. Our observations suggest that the MoRe SCPW resonator would be useful for integrating nano-hybrid spin or gatemon qubits and for developing spin-ensemble quantum memory devices.