Nanoscale confined mode ferromagnetic resonance imaging of an individual Ni81Fe19 disk using magnetic resonance force microscopy (invited)

We demonstrate and characterize the localized Ferromagnetic Resonance (FMR) modes created in an individual micron-sized Ni81Fe19 disk by means of a strong inhomogeneous probe field applied anti-parallel to the saturated magnetization of the sample. Our variational calculation accurately predicts the frequencies of the localized modes in FMR spectra, and characterizes the sizes and all related internal magnetic fields of the Bessel function modes in a simple model analogous to particle wavefunctions in a quantum well. The localized modes enable FMR imaging of the nonuniform demagnetizing field inside a Py disk demonstrating a novel magnetic resonance imaging technique able to map internal fields in ferromagnets with spectroscopic accuracy.

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