Aligned stripe magnetic domains in a Pt/Co/Pt film induced by a step-terrace substrate

Pt/Co/Pt trilayers were deposited on flat and step-terrace Al₂O₃ substrates to study the influence of surface morphology on the perpendicular magnetic anisotropy (PMA) and magnetic domain structure. The total thickness of the Pt/Co/Pt trilayers was minimized to resemble the step-terrace morphology of the substrate, which possessed a terrace width and height in the ranges of approximately 90–165 nm and 1.8–4.2 nm. The flat surface of the Pt/Co/Pt trilayers exhibited many small-dot domains or few large-block domains, whereas the terrace surface exhibited highly aligned stripe domains parallel to the longitudinal direction of the step-terrace Al₂O₃ substrate. The width of the stripe domains was within a range of approximately 500–700 nm, and the length of the stripe domains exceeded a few hundred micrometers. An anisotropic domain-wall motion in the longitudinal direction of the step-terrace may be used to control the operation of a magnetic device, such as a racetrack memory.