Perpendicularly magnetized Ni/Pt (001) epitaxial superlattice

A perpendicularly magnetized ferromagnetic layer is an important building block for recent/future high-density spintronic memory applications. This paper reports the fabrication of perpendicularly magnetized Ni/Pt superlattices and the characterization of their structures and magnetic properties. The optimization of film growth conditions allowed us to grow epitaxial Ni/Pt (001) superlattices on SrTiO3 (001) single-crystal substrates. We investigated their structural parameters and magnetic properties as a function of the Ni layer thickness and obtained a high uniaxial magnetic anisotropy energy of 1.9×106erg/cm3 for a [Ni (4.0 nm)/Pt (1.0 nm)] superlattice. In order to elucidate the detailed mechanism on perpendicular magnetic anisotropy for the Ni/Pt (001) superlattices, the experimental results were compared with the first-principles calculations. It has been found that the strain effect is a prime source of the emergence of perpendicular magnetic anisotropy.