Microscopic correlation between magnetostriction and magnetic damping

TL;DR

This study reveals that in certain magnetic alloys, the sign of magnetostriction directly influences magnetic damping through strain-induced electronic structure changes, offering insights for designing advanced magnetic materials.

Contribution

It uncovers the intrinsic link between magnetostriction sign and magnetic damping via electronic structure modifications in specific alloys.

Findings

Magnetic damping magnitude depends on magnetostriction sign.

Strain-induced exchange splitting affects spin density of states.

Locally degenerate orbitals influence magnetostriction.

Abstract

Although the relationship between magnetostriction and magnetic damping is often described phenomenologically, their intrinsic connection remains unclear. In this study, we demonstrate that the magnitude of magnetic damping depends on the sign of magnetostriction in ($\mathrm{Fe_{1-x}Co_{x})_{4}N}$ and $\mathrm{Ni_{1-y}Co_{y}}$ alloys across various compositions, consistent with experimental observations. This behavior is attributed to strain-induced changes in exchange splitting, which shift the minority spin density of states near the Fermi level, thereby affecting both magnetostriction and damping through spin-conserving transitions. Additionally, the presence of locally degenerate orbitals plays a crucial role in determining magnetostriction. These findings suggest that magnetization dynamics and magnetostriction can be intrinsically controlled, facilitating the design of magnetic materials for applications such as flexible spintronics.