Spin-torque microwave detector with out-of-plane precessing magnetic moment

Operation of a spin-torque microwave detector (STMD) in a weak perpendicular bias magnetic field has been studied theoretically. It is shown that in this geometry a novel dynamical regime of STMD operation, characterized by large-angle out-of-plane magnetization precession, can be realized. The excitation of the large-angle precession has threshold character and is possible only for input microwave currents exceeding a certain frequency-dependent critical value. The output voltage of an STMD increases with the frequency of the input signal, but is virtually independent of its power. An STMD operating in the out-of-plane regime can be used as a non-resonant threshold detector of low frequency microwave signals and for applications in microwave energy harvesting.