Low temperature growth of Co₂MnSi films on diamond semiconductors by ion-beam assisted sputtering

High quality Schottky junctions using Co₂MnSi/diamond heterostructures were fabricated. Low temperature growth at ∼300-400 °C by using ion-beam assisted sputtering (IBAS) was necessary to obtain abrupt Co₂MnSi/diamond interfaces. Only the Co₂MnSi films formed at ∼300-400 °C showed both saturation magnetization comparable to the bulk values and large negative anisotropic magnetoresistance, which suggests half-metallic nature of the Co₂MnSi films, of ∼0.3% at 10 K. Schottky junctions formed using the Co₂MnSi films showed clear rectification properties with rectification ratio of more than 10⁷ with Schottky barrier heights of ∼0.8 eV and ideality factors (n) of ∼1.2. These results indicate that Co₂MnSi films formed at ∼300-400 °C by IBAS are a promising spin source for spin injection into diamond semiconductors.