Tunnel magnetoresistance effect and magnetic damping in half-metallic Heusler alloys

Abstract

Some full-Heusler alloys, such as Co 2 MnSi and Co 2 MnGe, are expected to be half-metallic ferromagnetic material, which has complete spin polarization. They are the most promising materials for realizing half-metallicity at room temperature owing to their high Curie temperature. We demonstrate a huge tunnel magnetoresistance effect in a magnetic tunnel junction using a Co 2 MnSi Heusler alloy electrode. This result proves high spin polarization of the Heusler alloy. We also demonstrate a small magnetic damping constant in Co 2 FeAl epitaxial film. The very high spin polarization and small magnetic constant of Heusler alloys will be a great advantage for future spintronic device applications.