Realization of mutual synchronization of spin torque nano-oscillators under room temperature by noise reduction technique

The pragmatic use of Spin Torque Nano-Oscillators (STNOs) in real electronic systems is severely hindered due to their low output power and poor noise figure. The most accepted and promising way to increase the output power and decrease the signal noise of STNOs is through their mutual synchronization. However, it is confused that the mutual synchronization of STNOs is very difficult to achieve at room temperature although the non-linear nature of STNOs contributes to the large frequency range of injection locking. In this work, first, it is revealed that the difficulty of STNOs' mutual synchronization stems from the high output signal noise of STNOs. Based on this observation, a noise reduction technique is invented, which introduces a Band Pass Filter in the coupling loop of STNOs. Using the noise reduction technique, it is demonstrated that even non-identical STNOs can be mutually synchronized at room temperature.