Nonreciprocal Spin Wave Propagation Between Superconducting Waveguides on YSGG/YIG Thin-Film

Hybrid magnonic systems provide promising platforms for coherent information transfer and manipulation using magnons in magnetic materials, offering broadband frequency tunability and strong nonreciprocity [1, 2]. For on-chip quantum implementations, it is crucial to realize low-damping magnetic films that maintain coherence at cryogenic temperatures and can be seamlessly integrated with superconducting circuits. Here, we demonstrate nonreciprocal propagation of spin waves in a superconducting magnonic device composed of a 100-nm-thick Yttrium Iron Garnet (YIG) film grown on a cryogenically compatible Yttrium Scandium Gallium Garnet (YSGG) substrate and 30-nm-thick, 1-μm-wide NbN coplanar waveguide (CPW) antennas patterned on the YIG film. Both Damon–Eshbach (DE) and backward-volume (BV) spin wave modes were observed, with the DE mode exhibiting pronounced nonreciprocity in transmission amplitude. This nonreciprocal spin wave propagation, realized in a superconducting-compatible magnonic platform, represents a key step toward unidirectional quantum state transfer via magnetic waveguides [3].

[1] M. Song et al., Nature Communications 16, 3649 (2025)

[2] Y. Li et al., Applied Physics Letters 123, 022406 (2023)

[3] Z. Jiang et al., Applied Physics Letters 123, 130501 (2023)