Ferromagnetic resonance and magnetic damping in C-doped Mn5Ge3

TL;DR

This study investigates the magnetic properties and damping mechanisms of C-doped Mn5Ge3 thin films using ferromagnetic resonance, revealing insights into anisotropy, damping parameters, and relaxation processes relevant for spintronic applications.

Contribution

It provides the first detailed analysis of FMR and magnetic damping in C-doped Mn5Ge3 thin films, highlighting the effects of C-doping on magnetic relaxation and anisotropy.

Findings

Small FMR linewidth indicating high material quality

Perpendicular magnetic anisotropy increases at low temperature

Two-magnon scattering dominates magnetic relaxation

Abstract

Ferromagnetic resonance (FMR) was used to investigate the static and dynamic magnetic properties of carbon-doped Mn5Ge3 (C$_{0.1}$ and C$_{0.2}$) thin films grown on Ge(111). The temperature dependence of magnetic anisotropy shows an increased perpendicular magneto-crystalline contribution at 80K with an in-plane easy axis due to the large shape contribution. We find that our samples show a small FMR linewidth (corresponding to an intrinsic magnetic damping parameter $\alpha$=0.005), which is a measure of the spin relaxation and directly related with the magnetic and structural quality of the material. In the perpendicular-to-plane geometry, the FMR linewidth shows a minimum at around 200K for all the samples, which seems to be not correlated to the C-doping. The magnetic relaxation parameters have been determined and indicate the two-magnon scattering as the main extrinsic contribution. We observe a change in the main contribution from scattering centres in Mn5Ge3C0.2 at low temperatures, which could be related to the minimum in linewidth.