Structural and magnetic properties of epitaxial thin films of Co₂TiSn full Heusler Alloy with TiN buffer layer

Achieving high-quality thin films in complex epitaxial structures is widely known to require the selection of high-quality substrates and buffer layers with low epitaxial mismatch. In the case of metal-on-oxide epitaxy, metallic buffer layers serve an important role in preventing island growth and secondary phases. Thin films of the full Heusler compound Co₂TiSn were grown on hexagonal Al₂O₃ (1120 and 0001) substates, with a TiN buffer layer using the off-axis sputter beam epitaxy technique. X-ray diffraction and reflectivity measurements revealed the presence of high-quality single-crystal films with minimal surface roughness and an impressively narrow full-width at half-maximum (FWHM) for the rocking curve, measuring as low as 0.04°. Scanning electron microscopy showed a flawlessly smooth film surface devoid of any voids or pinholes. The magnetic measurements yielded results that closely matched the reported values and these findings will be showcased during the presentation.