Angular dependence of the electrically driven and detected ferromagnetic resonance in Ni$_{36}$Fe$_{64}$ wires

Abstract

We study the angular dependence of ferromagnetic resonance (FMR) in Ni$_{36}$Fe$_{64}$ wires using both traditional microwave-absorption and electrical-detection techniques. In our experiments we apply a static magnetic field at an angle $\theta$ with respect to the wire, while the microwave current, which is responsible for driving FMR, is always flowing along the wire. For different $\theta$s we find a very similar behavior for both microwave-absorption and electrically-detected FMR -- the resonance magnetic field follows a simple "$1/\cos(\theta)$" dependence. This simple behavior highlights the importance of the relative orientation between the driving current and magnetic field. We also investigated the dependence of the electrically detected FMR on dc and rf (microwave) current magnitudes. As expected, the resonance signal increases linearly with both the applied dc current and the microwave power.