Step-induced unusual magnetic properties of ultrathin Co/Cu films:Ab initiostudy

Abstract

We have performed ab initio studies to elucidate the unusual magnetic behavior recently observed in epitaxial Co films upon absorption of submonolayers of Cu and other materials. We find that a submonolayer amount of Cu on a stepped Co/Cu (100) film changes dramatically the electronic and magnetic structure of the system. The effect is mainly due to hybridization of Co and Cu $d$ electrons when copper forms a "wire" next to a Co step at the surface. As a result, a noncollinear arrangement of magnetic moments (switching of the easy axis) is promoted.