Effects of lateral size on the ferromagnetic resonance response in magnetic nanopillars

In this work, we investigate the effects of lateral size on the ferromagnetic resonance (FMR) response, a widely used technique to extract magnetic characteristics from thin films, which, in turn, are used as device parameters in structures such as magnetic tunnel junctions (MTJs). However, FMR experiments require larger samples to provide enough signal, so measurements are not performed on actual device dimensions. It is shown here using rigorous simulation tools that the FMR response is affected by lateral size, where higher order modal contributions can be found. Both the resonance frequency and linewidth are found to vary with lateral size, with as much as ~20% increase for a 200 nm difference in device radius.