Influence of magnetic domain-wall width and shape on magnetoresistance measurements

The influence of magnetic domain walls (DWs) on magnetoresistance in variou s exchange-bias ferrimagnetic/(ferrimagnetic or ferromagnetic) bilayer syst ems (Gd68Fe32/Tb55Fe45 and Fe60Gd40/Fe55Sn45) is presented. These systems a llow one to create well-defined DWs of various size and shape. The DW morph ology is controlled by the applied magnetic field in the film plane. By cha nging the amplitude of the field, the DW thickness can be controlled, where as the rotation of the field in plane allows one to create a theta degrees Bloch DW (90 degrees DW, 180 degrees DW,...). The electrical resistivity of the sample was measured relative to the applied magnetic field (amplitude and direction). The influence of the shape and size of the DW on magnetores istance was followed. For the two amorphous samples, it made it possible to fit the variation of resistivity relative to the DW thickness and shape us ing a model based on anisotropic magnetoresistance. (C) 2001 American Insti tute of Physics.