Strong Coupling between Magnons and Microwave Photons in On-Chip Ferromagnet-Superconductor Thin-Film Devices

Abstract

We demonstrate strong magnon-photon coupling of a thin-film permalloy device fabricated on a coplanar superconducting resonator. A coupling strength of 0.152 GHz and a cooperativity of 68 are found for a 30-nm-thick permalloy stripe. The coupling strength is tunable by rotating the biasing magnetic field or changing the volume of permalloy. We also observe an enhancement of magnonphoton coupling in the nonlinear regime of the superconducting resonator, which is mediated by the nucleation of dynamic flux vortices. Our results demonstrate a critical step towards future integrated hybrid systems for quantum magnonics and on-chip coherent information transfer.

Interplay of quantum phase transition and flat band in hybrid lattices

“…Regarding experimental implementations, while we have considered here a hybrid superconducting circuit with the ensembles of spins in diamond crystal coupled to the transmission line resonators (forming the Dicke model) [59][60][61][62][63][64], our proposal is not limited to this particular architecture and could be implemented or adapted in a variety of platforms, e.g., atomic [65,66], molecular [67], and ferromagnetic [68][69][70][71] systems coupled to superconducting cavities. For our specific design, considering an ensemble with N ∼ 10 12 spins and the single spin coupling λ 0 ∼ 10 Hz, an enhanced collective coupling λ ≈ √ Nλ 0 ∼ 10 MHz [59][60][61][62][63][64] allows our model to reach an ultrastrong-coupling regime, which demonstrates that the critical coupling of QPT can be readily realized with state-of-the-art technology.…”

Quantum Engineering With Hybrid Magnonic Systems and Materials (Invited Paper)

“…On-chip implementation and integration of quantum magnonic systems are highly desirable for circuit-based applications and building up complex networks of coupled magnonic systems. 21,22 One direct approach is to integrate magnetic devices with coplanar superconducting resonators, 11,[23][24][25][26][27] which can carry long-coherence microwave photons and couple with superconducting qubits for building up circuit quantum electrodynamics (cQED).…”

“…(1), in order to increase g with a limited magnetic device volume V M (or N ), it is important to have a small V c , which leads to a large coupling strength per Bohr magneton defined as g 0 = g/ √ N . Recently, Li et al 25 and Hou et al 26 have demonstrated strong magnon-photon coupling between permalloy (Ni 80 Fe 20 , Py) thin-film devices and coplanar superconducting resonators. As shown in Figs.…”

Probing magnon–magnon coupling in exchange coupled Y$$_3$$Fe$$_5$$O$$_{12}$$/Permalloy bilayers with magneto-optical effects

“…To date, both magnon–photon and magnon–magnon couplings are predominantly investigated by the cavity ferromagnetic resonance (FMR) spectroscopy, i.e. microwave transmission and/or reflection measurements, typically involving a vector-network analyzer (VNA) or a microwave diode 5 , 7 – 13 , 30 – 33 , 35 . Strong magnon–magnon couplings have been observed in yttrium iron garnet (Y Fe O , YIG) coupled with ferromagnetic (FM) metals, where exchange spin waves were excited by a combined action of exchange, dampinglike, and/or fieldlike torques that are localized at the interfaces 30 – 33 .…”