Nucleation of periodic domain structure in micro-fabricated spin valve strip pattern

Local magnetization reversal in a lithographically fabricated sub-μm spin valve strip has been performed with spatially modulated magnetic fields, produced by overlaid parallel conductor lines with 5 μm line width and 5 μm separation. Evaporated spin valve of NiFe/Co/Cu/Co was used for the material. Nucleation of periodic domains in the soft magnetic layer was confirmed with the ratio of the current induced MR change to the whole MR change attained with an external field. The critical current densities required for the magnetization reversal were 15 and 23 mA/μm for strips with 0.4 and 0.2 μm width. The current induced magnetic field calculated from the critical current was 50% larger than the external reverse field