Tailoring the magnetodynamic properties of nanomagnets using magnetocrystalline and shape anisotropies

TL;DR

This study demonstrates how the dimensions of nanomagnets can be engineered to balance magnetocrystalline and shape anisotropies, thereby tailoring their magnetodynamic properties through combined experimental and simulation approaches.

Contribution

It introduces a method to control nanomagnet dynamics by adjusting size and accounts for edge defect effects, advancing nanomagnetic device design.

Findings

Dynamical properties are size-dependent and controllable.

Edge defects significantly influence edge-localized modes.

Size tuning enables tailored magnetodynamic responses.

Abstract

Magnetodynamical properties of nanomagnets are affected by the demagnetizing fields created by the same nanoelements. In addition, magnetocrystalline anisotropy produces an effective field that also contributes to the spin dynamics. In this article we show how the dimensions of magnetic elements can be used to balance crystalline and shape anisotropies, and that this can be used to tailor the magnetodynamic properties. We study ferromagnetic ellipses patterned from a 10 nm thick epitaxial Fe film with dimensions ranging from 50 x 150 nm to 150 x 450 nm. The study combines ferromagnetic resonance (FMR) spectroscopy with analytical calculations and micromagnetic simulations, and proves that the dynamical properties can be effectively controlled by changing the size of the nanomagnets. We also show how edge defects in the samples influence the magnetization dynamics. Dynamical edge modes localized along the sample edges are strongly influenced by edge defects, and this needs to be taken into account in understanding the full FMR spectrum