Crossed-ratchet effects and domain wall geometrical pinning

Abstract

The motion of a domain wall in a two-dimensional medium is studied by taking into account the internal elastic degrees of freedom of the wall and geometrical pinning produced by both holes and sample boundaries. This study is used to analyze the geometrical conditions needed for optimizing crossed-ratchet effects in periodic rectangular arrays of asymmetric holes, recently observed experimentally in patterned ferromagnetic films. Exact calculation as a function of the geometry of the sample and numerical simulations have been used to obtain the anisotropic critical fields for depinning flat and kinked walls in rectangular arrays of triangles. The aim is to show with a generic elastic model for interfaces how to build a rectifier able to display crossed-ratchet effects or effective potential landscapes for controlling the motion of interfaces or invasion fronts.