Towards a full Heusler alloy showing room temperature half-metallicity at the surface

TL;DR

This study demonstrates that careful surface preparation of a Co2Cr0.6Fe0.4Al Heusler alloy film can achieve the highest room temperature surface spin polarization measured to date, approaching half-metallicity.

Contribution

It provides the first measurement of near 45% room temperature spin polarization at the surface of a full Heusler alloy, highlighting the importance of surface preparation.

Findings

Achieved up to 45% spin polarization at room temperature

Surface preparation critically affects spin polarization levels

First to report high surface spin polarization in full Heusler alloys at room temperature

Abstract

In this article we investigate the surface spin polarization in a 100 nm Co2Cr0.6Fe0.4Al (CCFA) film grown ex situ epitaxially on MgO(100) with a 10 nm Fe buffer layer by means of spin resolved photoemission. We show that a careful in situ preparation of the sample surface leads to values for the room temperature spin polarization up to 45% at the Fermi level. To our knowledge, this is the highest value measured so far at the surface region of a full Heusler alloy at room temperature.