Thermally enhanced perpendicular magnetic anisotropy behaviors of ultrathin [Co/Pd](n) multilayers via NiOx capping layer

Abstract

We report the enhanced perpendicular magnetic anisotropy (PMA) features of ultrathin [Co/Pd](3) multilayers (MLs) employing a NiOx insertion layer at high annealing temperatures. Thermally enhanced PMA in [Co/Pd](3)/NiOx (capping layer) MLs were achieved at a specific capping layer thickness, while no PMA responses were observed for a NiOx (buffer layer)/[Co/Pd](3) ML, regardless of NiOx thickness. X-ray diffraction observations, including rocking curves, identified the relatively different crystalline characteristics of the NiOx capping and buffer layers. Origin of the enhanced PMAs of [Co/Pd](3) MLs containing a NiOx capping layer is described based on the NiOx capping effect possibly providing additional Co/Oxide i-PMA under high-temperature annealing.