Investigation of the growth and magnetic properties of highly oriented films of the Heusler alloy Co2MnSi on GaAs(001)

TL;DR

This study explores the growth, magnetic properties, and spin polarization of highly oriented Co2MnSi films on GaAs(001), revealing their potential for spintronic applications with specific magnetic and transport characteristics.

Contribution

It demonstrates the successful growth of highly oriented Co2MnSi films on GaAs(001) without buffer layers and characterizes their magnetic and transport properties, including spin polarization.

Findings

Saturation magnetization slightly below bulk value.

Lowest resistivity and coercivity at 689 K substrate temperature.

Spin polarization around 55%.

Abstract

Highly (001) oriented thin films of Co2MnSi have been grown on lattice matched GaAs(001) without a buffer layer. Stoichiometric films exhibited a saturation magnetization slightly reduced from the bulk value and films grown at the highest substrate temperature of 689 K showed the lowest resistivity (33 micro.ohm.cm at 4.2 K) and the lowest coercivity (14 Oe). The spin polarization of the transport current was found to be of the order of 55% as determined by point contact Andreev reflection spectroscopy. The reduced magnetization obtained was attributed to the antiferromagnetic Mn2As phase. Twofold in-plane magnetic anisotropy was observed due to the inequivalence of the <110> directions, and this was attributed to the nature of the bonding at the reconstructed GaAs surface.