Coherently suppressed ringing of the magnetization in microscopic giant magnetoresistive devices

We study the magnetotransport response of 1 μm×4 μm size spin valve elements to ultrashort (pulse length 0.2–4 ns) easy axis magnetic field pulses. When applying an additional static hard axis field, pronounced magnetic precession is observed in the magnetoresistance. Damped precession occurs after the setting of the pulse and after pulse termination (“ringing”). The strength of the ringing can be controlled by adjusting the ratio of the precession period to the effective pulse length. When the pulse length matches the precession period, the ringing after pulse termination is effectively suppressed.