Oscillatory dependence of current-driven magnetic domain wall motion on current pulse length

Several decades ago computers used devices called magnetic bubble memories, in which information was stored in small magnetized areas defined by domain walls. The domain walls, where the magnetization changes its direction, were moved by magnetic fields. This otherwise attractive technology had problems with reliability and scaling and gradually fell out of favour. Today an entirely new way of moving domain walls, using short pulses of electrical current, could make bubble memory devices feasible at the nanoscale. Thomas et al. use this technique to move domain walls in ferromagnetic wires on very short timescales, by applying nanosecond-long pulses. They also observe an intriguing 'boomerang' effect, where the domain walls are driven out of their confining potential, in the opposite direction to the current pulse.