Magnetic resonance studies of the fundamental spin-wave modes in individual submicron Cu/NiFe/Cu perpendicularly magnetized disks

TL;DR

This study uses magnetic resonance force microscopy and micromagnetic simulations to investigate the fundamental spin-wave modes in individual submicron Cu/NiFe/Cu disks, revealing localized lowest energy modes at the interface.

Contribution

It demonstrates the localization of the lowest energy spin wave mode in sub-micron perpendicularly magnetized disks, combining experimental MRFM measurements with 3D micromagnetic simulations.

Findings

Lowest energy mode is localized at the Py/Cu interface

Spin wave spectra measured individually for each disk

Micromagnetic simulations confirm experimental observations

Abstract

Spin wave spectra of perpendicularly magnetized disks with trilayers consisting of a 100 nm permalloy (Py) layer sandwiched by two Cu layers of 30 nm, are measured individually with a Magnetic Resonance Force Microscope (MRFM). It is demonstrated by 3D micromagnetic simulations that in disks having sub-micron size diameters, the lowest energy spin wave mode of the saturated state is not spatially uniform but rather is localized at the center of the Py/Cu interface in the region of a minimum demagnetizing field.