Critical current and linewidth reduction in spin-torque nano-oscillators by delayed self-injection

TL;DR

This paper demonstrates that delayed self-injection in spin-torque nano-oscillators can significantly reduce critical current and linewidth, enhancing oscillator performance through theoretical modeling and numerical simulations.

Contribution

It introduces a method of delayed self-injection to improve spin-torque oscillator efficiency, supported by analytical and simulation results.

Findings

Critical current reduced by up to 25%

Linewidth decreased by a factor of 4

Applicable to various spin-torque oscillators

Abstract

Based on theoretical models, the dynamics of spin-torque nano-oscillators can be substantially modified by re-injecting the emitted signal to the input of the oscillator after some delay. Numerical simulations for vortex magnetic tunnel junctions show that with reasonable parameters this approach can decrease critical currents as much as 25 % and linewidths by a factor of 4. Analytical calculations, which agree well with simulations, demonstrate that these results can be generalized to any kind of spin-torque oscillator.