Symmetric and asymmetric domain wall diodes in magnetic nanowires

Micromagnetic simulations reveal how transverse domain walls couple with triangular diodes in magnetic nanowires. For symmetric diodes, the coupling explains the observed differences in the magnetic field required to depin domain walls traveling in opposite directions. In asymmetric diodes, the wall-triangle interaction can lead to order-of-magnitude differences in the depinning fields of oppositely magnetized walls traveling in the same direction. The asymmetric structures therefore combine the diode function of the symmetric structures with domain wall chirality filtering. We also show how two back-to-back diodes may be used to trap a domain wall and form a memory element. (C) 2007 American Institute of Physics.