Approximate theory of microwave generation in a magnetic nano-contact driven by a spin-polarized current

A simple analytic theory based on the assumption that a large angle quasiuniform precession of magnetization is excited in-a "free" ferromagnetic layer traversed by spin-polarized current at different external bias magnetic field orientations is demonstrated. The theory is based on the classical Hamiltonian formalism for spin waves in magnetic films and gives good qualitative and even partly quantitative explanation of the majority of experimental facts observed in literature.