Strong magnon-photon coupling with chip-integrated YIG in the zero-temperature limit

Abstract

The cross-integration of spin-wave and superconducting technologies is a promising method for creating novel hybrid devices for future information processing technologies to store, manipulate, or convert data in both classical and quantum regimes. Such hybrid devices can exhibit interesting properties such as new resonance spectra features induced by the interchange between superconducting microwave lines and ferromagnetic resonance dynamics of yttrium iron garnet (Y3Fe5O12, YIG) films [1]. On the other hand, hybrid magnon-polariton systems have been typically studied using bulk YIG and three-dimensional microwave photon cavities [2,3]. Limitations in YIG growth have thus far inhibited its incorporation into CMOS compatible technology such as high quality factor superconducting quantum technology. To overcome this impediment, we have used Plasma Focused Ion Beam (PFIB) technology—taking advantage of precision placement down to the micron-scale—to integrate YIG with NbN superconducting microwave devices. Example hybrid devices are shown in Fig.1. Ferromagnetic resonance has been measured at milliKelvin temperatures on PFIB-processed YIG samples using planar microwave circuits. Furthermore, we demonstrate strong coupling between superconducting resonator and YIG ferromagnetic resonance modes by maintaining reasonably low loss while reducing the system down to the micron scale. This achievement of strong coupling on-chip is a crucial step toward fabrication of functional hybrid quantum devices that advantage from spin-wave and superconducting components. For more information, please see our recent publication [4]. This work was supported by the European Research Council under the Grant Agreements 648011 and 648604, the EPSRC through grant EP/M024423/1, the Leverhulme Trust, and the University of Glasgow.  Strong magnon-photon coupling with chip-integrated YIG in the zero-temperature limit