Fabrication of Co2MnAl Heusler Alloy Epitaxial Film Using Cr Buffer Layer

Abstract

Thin films of the full-Heusler compound, Co₂MnAl, were grown on Cr-buffered MgO(001) substrates at different growth temperature and post-annealing temperature by magnetron sputtering. Atomic force microscopy (AFM) and X-ray diffraction (XRD) measurements show that Cr-buffer layer can largely improve the surface morphology and structural quality of Co₂MnAl film. The (001)-oriented epitaxial growth and B2 structure were confirmed by XRD measurements for all prepared samples. The smallest surface roughness (∼2 Å) and an identical M _s value to the bulk value were obtained in the sample which was deposited at ambient temperature and post-annealed at 300°C.