Route to chaos by irregular periods: Simulations of parallel pumping in ferromagnets

Abstract
A peculiar route to chaos is known experimentally for magnetic parallel pumping. The periods of auto-oscillations become irregular at the onset of chaos, without previous cascades of period-doubling bifurcations. This route to chaos has been found by the simulation of parallel pumping of a single spin interacting with a cavity or, for multispin systems, coupled by exchange.