  The spin-torque ferromagnetic resonance (ST-FMR) in a bilayer system
consisting of a magnetic insulator such as Y3Fe5O12 and a normal metal with
spin-orbit interaction such as Pt is addressed theoretically. We model the
ST-FMR for all magnetization directions and in the presence of field-like
spin-orbit torques based on the drift-diffusion spin model and quantum
mechanical boundary conditions. ST-FMR experiments may expose crucial
information about the spin-orbit coupling between currents and magnetization in
the bilayers.
