Growth of [001]-oriented polycrystalline Heusler alloy thin films using [001]-textured Ag buffer layer on thermally oxidized Si substrate for spintronics applications

TL;DR

This study demonstrates the fabrication of highly textured, polycrystalline Heusler alloy thin films with strong [001] orientation on Si substrates, suitable for spintronic applications, using a novel Ag buffer layer and controlled sputtering conditions.

Contribution

It introduces a method to produce highly oriented Heusler alloy films on Si substrates with improved structural and magnetic properties for spintronics.

Findings

Achieved strong [001] orientation of CFGG films

High saturation magnetization close to theoretical value

Successful use of N2 in sputtering for buffer layer growth

Abstract

To utilize half-metallic Heusler alloys in practical spintronic devices, such as magnetic sensors and magnetic memories, the key is to realize highly textured and structurally ordered polycrystalline thin films. In this study, we fabricated polycrystalline Co2FeGa0.5Ge0.5 (CFGG) Heusler alloy films deposited on a [001]-oriented Ag buffer layer, which was achieved by introducing N2 into Ar during the sputtering process, on a thermally oxidized Si substrate. We obtained strongly [001]-oriented CFGG films with B2 ordering and a high saturation magnetization close to the theoretical value, which can provide highly spin-polarized electric and spin current sources in spintronic devices with industrial viability.