Mutual Phase-Locking of Microwave Spin Torque Nano-Oscillators

The spin torque effect is a consequence of the continued, required scaling of magnetic devices. The output of this device can be frequency modulated, phase-locked to a stable external source, and mutually phase-locked to a neighboring oscillating contact. Measurements further indicate that the oscillators are also phase-locked during the coincidence of their frequencies. We have verified that the combined output power during locking is proportional to the square of the sum of the individual oscillators´ voltage outputs as expected for the combination of two coherent signals. Furthermore this data implies a possibility to significantly increase oscillator power output from a micro-scale device by utilizing an array of N phase-locked oscillators with combined output power proportional to N².