Probing 3D magnetic nanostructures by dark-field magneto-optical Kerr effect

Magneto-optical techniques are key tools for the characterization of magnetic effects at a nanoscale. Here, we present the dark-field magneto-optical Kerr effect (DFMOKE), a technique we have recently developed for the characterization of three-dimensional magnetic nanostructures. We introduce the principles of DFMOKE, based on the separation of an incident beam into multiple reflected beams when focusing on a 3D nano-geometry. We show the key modifications needed in a standard focused MOKE magnetometer to perform these measurements. Finally, we showcase the power of this method by detecting the magnetic switching of a single tilted 3D nanowire, independently from the switching of a magnetic thin film that surrounds it. We obtain independent and simultaneous switching detection of the nanowire and the film for all nanowire dimensions investigated, allowing us to estimate a magnetic sensitivity of 7 x 10(-15) A m(2) for DFMOKE in the setup used. We conclude the article by providing perspectives of future avenues where DFMOKE can be a very powerful characterization tool in the future investigations of 3D magnetic nanostructures.

Automated summary

Magneto-optical techniques have been developed as key tools for characterizing magnetic effects at the nanoscale. In this study, the researchers introduce the dark-field magneto-optical Kerr effect (DFMOKE), a technique specifically designed for characterizing three-dimensional magnetic nanostructures. They demonstrate the principles of DFMOKE and modify a standard focused MOKE magnetometer to perform measurements. Finally, they showcase the power of DFMOKE by detecting the independent magnetic switching of a single tilted 3D nanowire and a magnetic thin film that surrounds it.