Precise control of interface anisotropy during deposition of Co/Pd multilayers

We demonstrate the control of perpendicular magnetic anisotropy (PMA) in multilayer films without modification of either the microstructure or saturation magnetization by tuning the Ar⁺ ion energy using remote plasma sputtering. We show that for [Co/Pd]₈ multilayer films, increasing the Ar⁺ ion energy results in a strong decrease in PMA through an increase in interfacial roughness determined by X-ray reflectivity measurements. X-ray diffraction and transmission electron microscope image data show that the microstructure is independent of Ar⁺ energy. This opens a different approach to the in-situ deposition of graded exchange springs and for control of the polarizing layer in hybrid spin transfer torque devices.