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In this work, fabrication of Mn3-xFexGa epitaxial thin films by using an ultra-high vacuum electron beam evaporation system, clarifying the relationship between composition of Fe, magnetic properties, crystal structure and film thickness were studied. The epitaxial growth of L21- ordered Mn-Fe-Ga thin films has been confirmed on the MgO (001) single crystalline substrate by using in-situ RHEED for all the samples. The a-axis was calculated by performing a lattice spacing analysis using RHEED patterns. From XRD, the L21(004) fundamental peak shift to the high angle side was confirmed as the film thickness decreased, which show that the c-axis becomes smaller. Decreasing of the c-axis and increasing of the a-axis was confirmed as the film thickness decreased from XRD and RHEED analysis, respectively. As the film thickness was reduced (tMn-Fe-Ga = 20 - 1 nm), increase of saturation magnetization (Ms) and magnetic anisotropy (Ku) are confirmed for all Mn-Fe-Ga thin films in which Fe is added to Mn-Ga. At tMn-Fe-Ga = 1 nm, the maximum extremely large Ku = 20.1 Merg/cm3 at x = 1.5 and maximum Ms = 878 emu/cm3 at x = 2.5 are confirmed. These results could be explained by the addition of Fe to Mn-Ga and the lattice distortion from the substrate into the film. Therefore, it was shown that the L21- ordered Mn3-xFexGa epitaxial thin film is one of the magnetic materials having the perpendicular magnetization film which is suitable for the MTJs application.
