Theory of perpendicular magnetic anisotropy induced by Rashba spin-orbit interaction in ferromagnetic ultrathin films

Ieda, Junichi   ; Barnes, S. E.*; Maekawa, Sadamichi

We develop a simple analytic theory for the existence and electrical control of perpendicular magnetic anisotropy (PMA) based on the Rashba spin-orbit interaction and the single band Stoner model of magnetism. We show the competition between the Rashba spin-orbit fields and the exchange interaction, reflecting electron correlations. This theory can potentially lead to a very large magnetic anisotropy arising from the internal electric fields, , which exist at, e.g., ferromagnetic/metal and ferromagnetic/oxide insulator interfaces but modified by the addition of an applied electric field . There is a Rashba splitting of the band structure leading to a quadratic, , contribution to the magnetic anisotropy, contrasting with a linear in doping effect.