Broadband ferromagnetic resonance of Ni81 Fe19 wires using a rectifying effect

The broadband ferromagnetic resonance (FMR) measurement has been carried out by using a rectifying effect in two sets of Ni81 Fe19 wires. One wire is deposited on the middle strip line of the coplanar waveguide (CPW) and another is deposited between two strip lines of the CPW, measuring the FMR induced by in-plane and out-of-plane magnetic fields, respectively. The FMR frequency is defined by detecting the magnetoresistance oscillation due to the magnetization dynamics induced by a radio frequency (rf) field. The magnetic-field dependence of the resonance frequency and the rectification spectrum are analytically interpreted based on our uniform magnetization precession model. These findings reveal that two distinct rectifying signals are anticipated by a rf field and a rf current, which can easily be controlled by engineering the ferromagnetic wire shape and the external field orientation. These fundamental understandings are crucial for future rf device applications in spintronics.