Electrical detection of large cone angle spin precession from the linear to the nonlinear regime

The spin precession cone angle in a 5 μm wide Py microstrip has been investigated systematically from the linear to the nonlinear regime. At low power excitations, the cone angle increases linearly with the amplitude of the microwave magnetic field h. However, when h exceeds a critical value, a foldover resonance lineshape shows up, and the precession cone angle starts to increase with h1/3. The maximum cone angle reported in the present study reaches 22°.