L1^sub 0^-ordered MnAl thin films with high perpendicular magnetic anisotropy

L10-ordered MnAl thin films were epitaxially grown by sputtering. The film composition dependences of structural and magnetic properties were systematically investigated in the MnAl thin films. Both the L10-ordered parameter and the perpendicular magnetic anisotropy energy strongly depended on the composition of the MnAl thin films. The MnAl thin films with a Mn composition of 53–54 at. % showed both the highest L10-ordered parameter and the perpendicular magnetic anisotropy. The substrate and annealing temperatures were optimized to improve the magnetic properties and surface morphology. We have fabricated MnAl thin films with both a very high K u of 12 × 106 erg/cm3 and a small surface roughness of ca. 0.2 nm by optimizing the film composition and substrate and annealing temperatures. These results are useful guidelines for the fabrication of highly L10-ordered MnAl thin films with a large perpendicular magnetic anisotropy.