Controlled depinning of domain walls in a ferromagnetic ring circuit

The authors have investigated dynamics of paired domain walls in a ferromagnetic ring circuit, driven by a variable pulsed magnetic field. The magnetic reversal accompanied by the propagations of the domain walls depends not only on the amplitude but also on the rise time of the applied pulsed magnetic field. The threshold of the rise time is found comparable to the propagation time of a domain wall along a half-path of the ring. This finding may be useful for the high speed operation of the magnetic logic devices based on the domain wall motion.