Tailored Multi-mode, High-Q Superconducting Nb Resonators: Unique Platform for Magnon-Photon Coupling

Superconducting resonators have previously been used for magnon-photon coupling, which facilitates quantum information transduction. In this work, we demonstrate robust superconducting Nb resonators that show closely spaced resonances with high quality (Q) factors. The fundamental frequencies ranging from 440 MHz to 668 MHz with second harmonics at 870 MHz and 1.3 GHz, offer extensive frequency coverage. They maintain resonance integrity by exhibiting useful Q-factors for many harmonics, even in magnetic fields up to 1 T at 1.7 K. These resonators provide a versatile platform for investigating magnon-photon interactions in hybrid magnonic systems, overcoming limitations of previous designs and offering the potential for broad frequency coverage and application in quantum information studies.