Influence of interlayer magnetostatic coupling on the ferromagnetic resonance properties of lithographically patterned ferromagnetic trilayers

The influence of magnetostatic coupling in a Ni81Fe19∕Cu∕Ni81Fe19 elliptical element on the ferromagnetic resonance (FMR) properties was experimentally and numerically investigated. Discontinuous variations in the FMR frequencies were observed when the relative orientation of magnetization was switched between parallel and antiparallel. Furthermore, the trilayer element exhibits field-insensitive FMR properties for magnetization of antiparallel orientation. This is attributable to the conflicted magnetic field dependence of the FMR frequency in the top and bottom Ni81Fe19 layers with antiparallel magnetization.