Effect of Temperature in Hysteretic Synchronization of Magnetic Vortex Spin-Torque Nano-Oscillators

The synchronization of vortex spin-transfer nano-oscillators (both nanopillar and nanocontact structures) with external microwave excitations is considered. A collective variables description is used to derive an analytical reduced-order model for the vortex core dynamics, which is able to predict all the possible oscillation regimes and hysteretic transitions among them. The influence of thermal fluctuations on hysteretic synchronization is studied by full micromagnetic simulations. The numerical results are in good agreement with the theory.