Effect of Ge layer thickness on the formation of Mn5Ge3 thin film on Ge/Si (1 1 1)

Official URL: http://dx.doi.org/10.1016/j.jmmm.2018.10.096

The effect of Ge buffer layer thickness on the formation of epitaxial Mn5Ge3films and their magnetic properties has been investigated. Epitaxial ferromagneticMn5Ge3thin films were deposited on Ge/Si (1 1 1) substrates using solid phase epitaxy. The crystalline quality, chemical composition and magnetic properties of thefilms were investigated by x-ray diffraction, transmission electron microscopy, x-ray photoelectron spectroscopy, electron spin resonance. Increasing the thickness ofthe Ge layer significantly enhanced the crystallinity and magnetic homogeneity of Mn5Ge3films. Both structural and magnetic investigations show substantialdiffusion of Mn atoms through Ge buffer layer which results in the formation of Mn5Si3and a delay in Mn5Ge3formation until the thickness of the Ge layer reaches to70 nm. The observed magnetic behavior for the films grown on different Ge thicknesses is interpreted in terms of changes in the magnetic phases and surfaceproperties. These results show that Mn5Ge3can be epitaxially grown on Si substrate with Ge buffer layer thicknesses of above 140 nm, despite ∼ 8% lattice mismatchbetween Mn5Ge3and Si (1 1 1)