Resonant transmission through a double domain wall in magnetic nanowires

Abstract

As experimentally verified, a large magnetoresistance arises due to domain walls creation (or destruction) in Ni nanowires and in some nanostructures based on GaMnAs magnetic semiconductors. Hence the presence and structuring of magnetic domain walls have important potential applications in magnetoelectronics devices. Here, we uncover a way of controlling the conductance via resonant transmission through a double domain wall structure. This phenomenon is due to quantum interference of charge carrier wave functions in spin quantum wells, which leads to the formation of quantized energy states in the potential well created by a double domain wall. When the energy of a state in the spin quantum well is resonant with the Fermi energy in the wire, the spin–flip transmission through the domain walls becomes most effective. This gives rise to a resonance-type dependence of the conductance on the distance between the domain walls or on the Fermi energy.