Magnetotransport in ferromagnetic Fe$_2$Ge semimetallic thin films

TL;DR

This study reports the first measurement of electrical and magneto-transport properties of ferromagnetic Fe$_2$Ge thin films, revealing strong spin polarization and potential for spintronic applications.

Contribution

It provides new experimental data on Fe$_2$Ge thin films, demonstrating their ferromagnetic and transport properties, and highlights their potential in spintronics.

Findings

High temperature resistivity maximum observed

Suppression of electron-magnon scattering at low temperatures

Presence of anomalous Hall effect and small negative magnetoresistance

Abstract

Thin films of the ferromagnet Fe$_2$Ge were grown via molecular beam epitaxy, and their electrical and magneto-transport properties measured for the first time. X-ray diffraction and vibrating sample magnetometry measurements confirmed the crystalline ferromagnetic Fe$_2$Ge phase. The observed high temperature maximum in the longitudinal resistivity, as well as the observed suppression of electron-magnon scattering at low temperatures, point to the presence of strong spin polarization in this material. Measurements of the Hall resistivity, $\rho_{xy}$, show contributions from both the ordinary Hall effect and anomalous Hall effect, $\rho_{xy}^{AH}$, from which we determined the charge carrier concentration and mobility. Measurements also show a small negative magnetoresistance in both the longitudinal and transverse geometries. Fe$_2$Ge holds promise as a useful spintronic material, especially for its semiconductor compatibility.