Speaker
Description
High-finesse optical nanocavities coupled with nanomechanical torque sensors have enabled highly sensitive and broadband readout of magnetic torques, from timescales involving quasi-static hysteresis response to radio-frequency magnetic susceptibility [1-3]. The extension of torque magnetometry to higher mechanical frequencies will grant further access to spin dynamics, including mechanical investigations of spin-lattice relaxation times.
For nanomechanical torque magnetometry measurements into radio frequencies, the contribution of the Einstein-de Haas (EdH) effect can become comparable to, and even exceed, the conventional magnetic torque (cross-product of magnetic moment and applied field) signal [4]. Extending sensitive optomechanical detection across a ladder of higher-order mechanical modes is a natural way to extract further information, through examination of the relative scaling of EdH and cross-product torques.
Sufficiently high-order mechanical modes have application to co-resonant detection of magnetic resonances. Magnetic vortex resonances intersecting the mechanical resonance spectrum will be described, and allow for the observation of dynamic vortex core interactions with magnetic inhomogeneities.
[1] M. Wu et al. Nat. Nanotechnol. 12, 127 (2017).
[2] G. Hajisalem et al. New J. Phys. 21, 095005 (2019).
[3] J. Losby et al. J. Phys D. 51, 483001 (2018).
[4] K. Mori et al. Phys. Rev. B. 102, 054415 (2020).
