Physics and Astronomy Colloquium - "From Hybrid Quantum Magnonics to Terahertz Spintronics" Professor Wei Zhang, Oakland University
This event is in the past.
Hybrid magnonic systems are great candidates for making interconnects between different quantum platforms, due to their coherent and strong coupling with other quantum excitations. The ability for sensitively and reliably probing the magnon dynamics in various novel spintronic and magnonic contexts are thus crucial, for example, involving state-of-the-art approaches using spin-torques, acoustic phonons, and microwave photons. I will discuss our recent results on the detection of phase-resolved magnetization dynamics using a cw-modulated laser technique, which allows a modulation at the GHz frequencies with both amplitude- and phase-control and also phase-locking to a microwave source. We show ferromagnetic resonance measurement of both metals and insulators, as well as the quantification of spin-orbit torques in ferromagnet/heavy-metal bilayers . We also demonstrated the facile optical detection of magnon-magnon coupling in Permalloy/Y3Fe5O12 bilayers using this technique via a combination of magneto-optical Kerr and Faraday effects [2,3]. In particular, these measurements provide direct information on how the excitation of magnons in permalloy modes may suppress the excitation of magnons in YIG analogous to previously observed magnetically-induced-transparency effects in magnon-photon hybrid systems. Finally, I will make connections to a new spintronic material system for achieving strong and controllable ultrafast dynamics beyond GHz and up to THz frequency range.
 Yi Li et al, “Simultaneous Optical and Electrical Spin-Torque Magnetometry with Phase-Sensitive Detection of Spin Precession”, Phys. Rev. Applied 11, 034047 (2019).
 Yuzan Xiong et al, “Probing the Magnon-Magnon Coupling using Combinatorial Magneto-Optical Kerr and Faraday Effects”, ArXiv: 1912.13407.
 Yi Li et al, “Coherent spin pumping in a strongly coupled magnon-magnon hybrid system”, Phys. Rev. Lett. in press (2020).