Enhancement of the response of non-uniform resonance modes of a nanostructure in the Picoprobe microwave-current injection ferromagnetic resonance

Abstract

The non-uniform standing spin-wave modes in thin magnetic films and nanostructures provide important information about surfaces and buried interfaces. Very often they are lacking in the recorded ferromagnetic resonance spectra for symmetry reasons. In this work we experimentally demonstrate that by direct injection of microwave currents into an array of Permalloy nanostripes using a microscopic microwave coaxial to coplanar adaptor one can efficiently excite non-uniform standing spin wave modes with odd symmetry. The proposed method is quick and allows easy spatial mapping of magnetic properties with the resolution down to 100 microns. We have validated this method using an example from a periodical array of nanostripes. The results from direct current injection are compared to that of microstrip-based FMR measurements.