Spin wave eigenmodes in transversely magnetized thin film ferromagnetic wires

Abstract

We report experimental and theoretical studies of spin wave eigenmodes in transversely magnetized thin film Permalloy wires. Using broadband ferromagnetic resonance technique, we measure the spectrum of spin wave eigenmodes in individual wires as a function of magnetic field and wire width. Comparison of the experimental data to our analytical model and micromagnetic simulations shows that the intrinsic dipolar edge pinning of spin waves is negligible in transversely magnetized wires. Our data also quantify the degree of extrinsic edge pinning in Permalloy wires. This work establishes the boundary conditions for dynamic magnetization in transversely magnetized thin film wires for the range of wire widths and thicknesses studied, and provides a quantitative description of the spin wave eigenmode frequencies and spatial profiles in this system as a function of the wire width.

Spin Hall-induced auto-oscillations in ultrathin YIG grown on Pt

“…Comparison of the simulated spectrum with that obtained by BLS shows a perfect agreement in the frequency of BM, while the experimentally obtained frequency of EM 2.5 GHz is higher than that observed in simulations. We emphasize that this result is in a good agreement with previous studies 10 , 32 . In particular, in ref.…”

“…In particular, in ref. 32 , it was shown that, in magnetic nanowires, the experimentally observed frequencies of the edge modes are always higher than those obtained from micromagnetic simulations. This frequency mismatch was attributed to an extrinsic pinning of the magnetization at the edges of the nanowire due to the joint action of the edge roughness, edge dilution effects, the non-zero surface anisotropy, etc.…”

Spin–orbit torque nano-oscillator with giant magnetoresistance readout

“…Such a high blue shift has been previously observed for auto-oscillatory edge spin-wave modes in AMR SHOs 15 . The edge spin-wave mode results from spatially inhomogeneous demagnetizing field at the nanowire edges that produces a magnetic potential well for spin-wave excitations 46,47 . The edge mode in nanowires exhibits maximum amplitude at the wire edge.…”

Spin caloritronic nano-oscillator

“…The field-frequency relation of the spin wave mode and thus the auto-oscillation frequency can be efficiently controlled via changing the nanowire width and thereby modifying its magnetic shape anisotropy 47 . For the nanowire magnetized by a transverse magnetic field, the resonance field increases (the resonance frequency decreases) with decreasing nanowire width 47 , as confirmed by our measurements of a 90 nm wide YIG/Pt nanowire described in the Supplementary Note 2 .…”