Anodic alumina with surface of hexagonal patterned nanodots was prepared by a two-step anodizing procedure. Scanning electron microscope and atomic force microscopy results clearly showed the formation of self-organized hexagonal patterned nanostructure. Diameters of the nanodots were controlled by choosing different anodization voltage and types of electrolyte acids. Co/Pt multilayers deposited on the nanodots with different diameters of 20, 70, and 100 nm lead to the formation of magnetic nanostructures with perpendicular anisotropy. Magnetometry and the first-order reversal curve method were used to study the magnetic properties of Co/Pt nanostructures. An out-of-plane magnetic easy axis was observed for the continuous films and the nanodots with diameters of 100 and 70 nm. The magnetic multilayers deposited on 20 nm nanodots appeared to have taken on a hard axis type behavior. The curvature of nanodot arrays induces strong modifications on the magnetic properties of the nanostructures.

The ability to control magnetic vortex is critical for their potential applications in spintronic devices. Traditional methods including magnetic field, spin-polarized current etc. have been used to flip the core and/or reverse circulation of vortex. However, it is challenging for deterministic electric-field control of the single magnetic vortex textures with time-reversal broken symmetry and no planar magnetic anisotropy. Here it is reported that a deterministic reversal of single magnetic vortex circulation can be driven back and forth by a space-varying strain in multiferroic heterostructures, which is controlled by using a bi-axial pulsed electric field. Phase-field simulation reveals the mechanism of the emerging magnetoelastic energy with the space variation and visualizes the reversal pathway of the vortex. This deterministic electric-field control of the single magnetic vortex textures demonstrates a new approach to integrate the low-dimensional spin texture into the magnetoelectric thin film devices with low energy consumption.