title: Phase-resolved ferromagnetic resonance using heterodyne detection method.
abstract: This paper describes a phase-resolved ferromagnetic resonance (FMR) measurement using a heterodyne method. Spin precession is driven by microwave fields and detected by 1550nm laser light that is modulated at a frequency slightly shifted with respected to the FMR driving frequency. The evolving phase difference between the spin precession and the modulated light produces a slowly oscillating Kerr rotation signal with a phase equal to the precession phase plus a phase due to the path length difference between the excitation microwave signal and the optical signal. We estimate the accuracy of the precession phase measurement to be 0.1 rad. This heterodyne FMR detection method eliminates the need for field modulation and allows a stronger detection signal at higher intermediate frequency where the 1/fnoise floor is reduced.
authors.affiliation: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD, USA; Maryland Nanocenter, University of Maryland, College Park, MD, USA.
authors.forename: Seungha
authors.initials: S
authors.lastname: Yoon
authors.affiliation: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Liu
authors.affiliation: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: McMichael