Domain wall diodes in ferromagnetic planar nanowires

We demonstrate a lithographically defined magnetic structure through which domain walls from planar magnetic nanowires propagate in one direction only, under an appropriate magnetic field. This domain wall diode is of the form of an isosceles triangle, with one nanowire emanating from its apex and one from its base. A domain wall arriving at the triangle apex, under an applied magnetic field, is able to overcome minor pinning through the diode and continue through the opposite nanowire. However, a domain wall arriving at the triangle base is unable to overcome the significant pinning energy presented by the sudden change in track width. Domain wall diodes are of potential use in controlling domain wall propagation for fundamental investigations and technological applications. (C) 2004 American Institute of Physics.