Edge-modulated perpendicular magnetic anisotropy in [Co/Pd][subscript n] and L1[subscript 0]-FePt thin film wires

Abstract

Thickness modulation at the edges of nanostructured magnetic thin films is shown to have important effects on their perpendicular magnetic anisotropy. Thin film wires with tapered edges were made from [Co/Pd][subscript 20] multilayers or L1[subscript 0]-FePt films using liftoff with a double-layer resist. The effect of edge taper on the reversal process was studied using magnetic force microscopy and micromagnetic modeling. In [Co/Pd][subscript 20], the anisotropy was lower in the tapered edge regions which switched at a lower reverse field compared to the center of the wire. The L1[subscript 0]-FePt wires showed opposite behavior with the tapered regions exhibiting higher anisotropy.