  Using micromagnetics we demonstrate that the r.f. field produced by a spin
valve can be used to reverse the magnetization in a magnetic nanoparticle. The
r.f. field is generated using a current that specifically excites a uniform
spin wave in the spin valve. This current is swept such that the
chirped-frequency generated by the valve matches the angular dependent resonant
frequency of the anisotropy-dominated magnetic nanoparticle, as a result of
which the magnetization reversal occurs. The switching is fast, requires
currents similar to those used in recent experiments with spin valves, and is
stable with respect to small perturbations. This phenomenon can potentially be
employed in magnetic information storage devices or recently discussed magnetic
computing schemes.
