Mn1.4Ga films with high perpendicular magnetic anisotropy and high crystalline quality were
grown on MgO substrates with Cr buffer layer using molecular beam epitaxy. The crystalline
structure and the surface morphology of the films have been systematically investigated as
functions of in-situ annealing temperature (Ta) and film thickness. It is found that the magnetic
properties can be largely tuned by adjusting Ta. As Ta increases, both saturation magnetization (Ms)
and uniaxial perpendicular magnetic anisotropy constant (Ku) increase to the maximum values of
612 emu/cc and 18 Merg/cc at 300 C, respectively, and then decrease. The morphology also
changes with Ta, showing a minimum roughness of 2.2A ° at Ta¼450 C. On the other hand, as the
thickness increases, Ms and Ku increase while coercivity decreases, which indicates there is a
magnetic dead layer with a thickness of about 1.5 nm at the interfaces. The detailed examination on
the surface morphology of the films with various thicknesses shows a complicated film
growth process, which can be understood from the relaxation mechanism of the interfacial strain.
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Copyright (2014) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in J. Appl. Phys. 115, 043902 (2014) and may be found at http://dx.doi.org/10.1063/1.4862172.