Tailoring Spin Dynamics by Magnetic Nanopatterning Using Ion Irradiation

Various elements like Pd, Cr, Ta, as well as several rare-earth elements can be used to modify the magnetic properties of thin ferromagnetic films. They are incorporated either by co-sputtering or ion implantation and are well known to reduce the Curie temperature, saturation magnetization, anisotropy and damping [1,2]. In combination with lithographic masking this allows for magnetic property patterning at the nanoscale [3]. In thin ferromagnetic films, the magnetization dynamics are governed by
intrinsic effects like Gilbert damping and spin-pumping but also by extrinsic effects like two-magnon scattering due to inevitable defect structures. By lithographic nanopatterning or by using ion-eroded, nanoscale periodically modulated substrates (ripples) as templates we are able to artificially create and thus control those defect structures necessary to induce two-magnon scattering. The damping contributions are disentangled from linewidth measurements by broadband ferromagnetic resonance technique.