We explore electrodeposited ordered arrays of Fe, Ni and Co nanorods embedded in anodic alumina membranes as a source of intense magnetic stray field gradients localized at the nanoscale. We perform a multiscale characterization of the stray fields using a combination of experimental methods (Magneto-optical Kerr effect, Virtual Bright Field Differential Phase Contrast Imaging) and micromagnetic simulations, and establish a clear correlation between the stray fields and the magnetic configurations of the nanorods. For uniformly magnetized Fe and Ni wires the field gradients vary following saturation magnetization of corresponding metal and the diameter of the wires. In the case of Co nanorods, very localized (~10 nm) and intense (> 1T) stray field sources are associated with the cores of magnetic vortexes. Confinement of that strong field at extremely small dimensions leads to exceptionally high field gradients up to 108 T/m. These results demonstrate a clear path to design and fine-tune nanoscale magnetic stray field ordered patterns with a broad applicability in key nanotechnologies, such as nanomedicine, nanobiology, nanoplasmonics and sensors.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: P.V., A.Ch., and M.P. acknowledge support from the Spanish Ministry of Economy, Industry and Competitiveness under the Maria de Maeztu Units of Excellence Programme - MDM-2016-0618, the Project FIS2015-64519-R, and (M.P.) the grant BES-2013-063690. J.L gratefully acknowledges postdoctoral research fellowships by the Fonds Wetenschappelijk Onderzoek (FWO-Vlaanderen) and the Ghent University Special Research Fund (BOF). We gratefully acknowledge the support of NVIDIA Corporation with the donation of the GPU’s used for this research. Y.P.I. acknowledge support from the grant 3.7383.2017/8.9 of Ministry of Education and Science of Russian Federation.