FePt nano-stripes fabricated on anodic aluminum oxide templates

A new FePt nanostructure with stripe-like patterns has been prepared by direct current (DC) magnetron sputtering on anodic aluminum oxide (AAO) templates. AAO templates anodized under low voltages (7 V) demonstrate self-organized, maze-like patterns, different from the conventional porous structures obtained at high voltages. FePt thin films deposited on such templates tend to replicate the morphology of the templates. Although there is no obvious spatial ordering, the dimensions of the FePt nano-stripes are highly uniform, due to the constrained growth along the transverse direction of the AAO pattern. The magnetic properties are strongly influenced by this unique morphology. While continuous films demonstrate strong exchange coupling, the dominant interaction in FePt nano-stripes with the same nominal thickness is magnetostatic. The morphology also dictates the magnetization reversal behaviors, with thin films dominated by domain nucleation; while nano-stripes incline to reverse their magnetization by spin rotation. Our work demonstrates that self-organized AAO templates can be used to control the morphology and magnetic behavior of FePt materials.