Highly Anisotropic Magnetic Domain Wall Behavior in In-Plane Magnetic Films.

We have studied the nucleation of magnetic domains and propagation of magnetic domain walls (DWs) induced by pulsed magnetic field in a ferromagnetic film with in-plane uniaxial anisotropy. In contrast to observed behavior in films with out-of-plane anisotropy, the nucleated domains have a rectangular shape in which a pair of the opposite sides are perfectly linear DWs, while the other pair present zigzags. The field induced propagation of these two DW types are found to be different. The linear ones follow a creep law identical to what is usually observed in out-of-plane films, while the velocity of zigzag DWs depends linearly on the applied field amplitude down to very low field. This unexpected feature can be explained by the shape of the DW, and these results provide first experimental evidence of the applicability of the 1D model in two-dimensional ferromagnetic thin films.