Fabrication of epitaxial Co2MnSi films on lattice-matched MgAl2O4 substrates by ion-beam assisted sputtering

We show that epitaxial Co2MnSi films can be fabricated on lattice-matched MgAl2O4 substrates using an ion-beam-assisted sputtering method. Low temperature growth below ~ 500 °C with Ar ion-beam assistance enabled high-quality Co2MnSi films with ideal saturation magnetization and highly-ordered L21 structures. The Co2MnSi films also demonstrated a negative anisotropic magnetoresistance of ~ 0.1% at room temperature, which is a typical characteristic of half-metals. These results suggest that ion-beam assisted sputtering is an effective method of fabricating high-quality, half-metallic Co2MnSi films at low growth temperatures.