Structural, magnetic and transport properties of thin films of the Heusler alloy Co2MnSi

TL;DR

This study investigates the structural, magnetic, and transport properties of Co2MnSi thin films grown on sapphire, revealing their high spin polarization, texture, and how properties vary with growth conditions and film thickness.

Contribution

It provides new insights into the growth, texture, magnetic saturation, and spin polarization of Co2MnSi thin films on sapphire substrates.

Findings

Films are single phase with strong (110) texture.

Highest substrate temperature yields lowest resistivity and coercivity.

Spin polarization of about 54% was measured.

Abstract

Thin films of Co2MnSi have been grown on a-plane sapphire substrates from three elemental targets by dc magnetron co-sputtering. These films are single phase, have a strong (110) texture and a saturation magnetization of 4.95 uB/formula unit at 10 K. Films grown at the highest substrate temperature of 715 K showed the lowest resistivity (47 uOhm cm at 4.2 K) and the lowest coercivity (18 Oe). The spin polarization of the transport current was found to be of the order of 54% as determined by point contact Andreev reflection spectroscopy. A decrease in saturation magnetization with decreasing film thickness and different transport behaviour in thinner films indicate a graded disorder in these films grown on non-lattice matched substrates.