  Energy-efficient switching of magnetization is a central problem in
nonvolatile magnetic storage and magnetic neuromorphic computing. In the past
two decades, several efficient methods of magnetic switching were demonstrated
including spin torque, magneto-electric, and microwave-assisted switching
mechanisms. Here we report the discovery of a new mechanism giving rise to
magnetic switching. We experimentally show that low-dimensional magnetic chaos
induced by alternating spin torque can strongly increase the rate of
thermally-activated magnetic switching in a nanoscale ferromagnet. This
mechanism exhibits a well-pronounced threshold character in spin torque
amplitude and its efficiency increases with decreasing spin torque frequency.
We present analytical and numerical calculations that quantitatively explain
these experimental findings and reveal the key role played by low-dimensional
magnetic chaos near saddle equilibria in enhancement of the switching rate. Our
work unveils an important interplay between chaos and stochasticity in the
energy assisted switching of magnetic nanosystems and paves the way towards
improved energy efficiency of spin torque memory and logic.
