Buffer Layer Effect on the Structure, Morphology, and Magnetic Properties of Mn5Ge3 Films Synthesized on Si(111) Substrates

The effect of the MnxGey buffer layer on the morphology, transport and magnetic properties of Mn5Ge3 thin films grown on substrates Si(111) has been studied. Using X-ray diffraction analysis and atomic force microscopy, it has been found that changing the thickness and structure of the buffer layer with a gradient MnxGey composition has made it possible to control the crystalline quality and smoothness of epitaxial films. Changes in the microstructure and surface roughness has not affected the temperature of the phase transitions revealed from the temperature dependences of the resistivity and magnetization at 75 and 300 K. It has been shown that the features of the magnetization curve shape for films with different buffer layers have been closely related to the inhomogeneity of the films in thickness and surface roughness while maintaining the micromagnetic constants and orientation of the easy magnetization axis. The value of the change in the magnetic part of entropy ΔS has been calculated to be 2.1 J kg–1 K–1 at 1 T, which is comparable with the value for gadolinium and exceeds that for Mn5Ge3(001) films grown on GaAs substrates.