Patent ID: 8922285

Claim:
An apparatus comprising a radiofrequency oscillator, said radiofrequency oscillator comprising a magnetoresistive device within which there flows a spin-polarized electrical current to generate an oscillating signal oscillating at an oscillation frequency on a output terminal, said magnetoresistive device comprising a stack that comprises a reference layer, said reference layer comprising a magnetic layer capable of spin-polarizing an electrical current and having a magnetization along a fixed direction, a free layer, said free layer comprising a magnetic layer having a magnetization that oscillates when said layer is crossed by a spin-polarized current, and a spacer layer, said spacer layer comprising a non-magnetic layer interposed between said free layer and said reference layer to form one of a tunnel junction and a spin valve, a current source for causing flow of electric current along a direction perpendicular to said free layer, said spacer layer, and said reference layer, a control terminal for controlling the frequency of said oscillating signal, and an automatic control loop connected between said output terminal and said control terminal to apply a control signal to said control terminal to automatically lock a characteristic of said oscillating signal into a reference value, said automatic control loop comprising a sensor for sensing an amplitude of oscillations of said oscillating signal, and a comparator for generating said control signal as a function of said amplitude measured and said reference value.