Monodomain configurations due to bias effect in NiO/NiFe microstructures

Magnetic domain configurations of microstructured permalloy exchange couple d by an antiferromagnetic (NiO) thin film is presented. NiO/NiFe bilayer mi crometer array elements were fabricated using electron beam lithography thr ough a lift-off technique. The magnetic force microscopy images of the elli ptical and rectangular elements with various aspect ratios showed dipole-li ke magnetic domain structures. The bright/dark arc contrast associated with the magnetic pole strength was dependent on the anisotropic exchange field . Furthermore, the shape anisotropy can overwhelm anisotropic exchange in p atterned elements with a high aspect ratio and thicker permalloy film. (C) 2000 American Institute of Physics. [S0021-8979(00)82708-5].