Structural and magnetic study of thin films based on anisotropic ternary alloys FeNiPt2

L10 ordered (Fe-Ni)50Pt50 alloy films with perpendicular magnetic anisotropy were successfully prepared by interdiffusing FePt(0 0 1) and NiPt(0 0 1) layers codeposited on MgO(0 0 1) substrates by MBE. The [0 0 1] growth direction corresponds to the epitaxy of the alloy on the substrate and is the interesting growth orientation to get a perpendicular magnetization. The X-ray diffraction shows a high L10 chemical order (S = 0.7 (plus-minus) 0.1). The easy magnetization direction is perpendicular for all samples. The MFM images display highly interconnected stripes corresponding to up and down orientations of the magnetization. Large uniaxial magnetic anisotropy (Ku = 9.10^5 J/m^3) and suitable magnetic transition temperature (TC = 400 K) are obtained. The addition of Ni changes the spin-orbit interaction in the FePt compound system, hence causes a decrease of anisotropy, saturation magnetization and coercivity.