Nanocavity optomechanical torque magnetometry and radiofrequency susceptometry

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Nanophotonic optomechanical devices offer high sensitivity for nanomechanical metrology.
• These devices have the potential to advance studies of nanoscale physical systems.

Discussion:

• A nanophotonic optomechanical torque magnetometer and RF susceptometer were developed.
• The device utilizes a nanocavity in a torsional nanomechanical resonator for exquisite readout sensitivity.
• It enables observation of net magnetization and RF-driven responses of single mesoscopic magnetic structures under ambient conditions.

Key Insights:

• The magnetic moment resolution allows observation of Barkhausen steps in magnetic hysteresis of a permalloy island.
• Enhanced RF susceptibility was observed, attributed to thermally assisted vortex core hopping between pinning sites.

Outlook:

• The on-chip magnetosusceptometer scheme provides a pathway for integrated cavity optomechanical devices.
• This technology promises quantitative characterization of magnetic micro- and nanosystems for science and technology.