Cavity magnonics with a van der Waals antiferromagnet
Abstract: Magnons, the quanta of collective spin oscillations, have gained recent interest towards potential application in data communication and computing. Recent advent of magnetism in van der Waals type layered materials gives a scope of applying them in hybrid quantum devices. Chromium trichloride (CrCl3) – a two-sublattice van der Waals antiferromagnet, shows a complex magnetization dynamics, and two primary antiferromagnetic resonance modes in GHz frequencies. Study of magnons in antiferromagnets is particularly interesting due to the absence of any net magnetization in absence of a finite magnetic field. This provides stability to the magnetic system with respect to external perturbations and results in less stray fields. In addition to the antiferromagnetic modes, we also find signature of standing spin-wave modes, which is promising for application in signal propagation. We combine magnons in CrCl3 with microwave photons in niobium nitride (NbN) coplanar waveguide (CPW) resonators to realize magnon-photon coupling. The choice of NbN, a type II disordered superconductor, was motivated by the requirement of a cavity that can retain high Q in presence of magnetic field. A large coupling strength for both the antiferromagnetic modes with the cavity mode, with an order of magnitude close to the mode frequencies themselves, makes this a potentially useful system for application in hybrid cavity magnonics devices.
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2. Mandal et. al., Applied Physics Letters 117, 263101 (2020)
About the QSQM: The EFRC-QSQM center aims to develop and apply nontrivial quantum sensing to measure and correlate local and nonlocal quantum observables in exotic superconductors, topological crystalline insulators, and strange metals. The center is led by the University of Illinois at Urbana-Champaign in partnership with the University of Illinois at Chicago and the SLAC National Accelerator Laboratory.