Domain-wall trapping in controlled mesoscopic ferromagnetic wire junctions

The domain configurations in permalloy wires (30 nm thick, 1-50 μm wide and 210 μm long) with a central 'bowtie' (10 μm long) were investigated in both their demagnetized and remanent states using magnetic force microscopy (MFM) and the results were confirmed by micromagnetic calculations. Domain walls were found to be trapped at both ends of the bowtie, suggesting that domain-wall trapping is the dominant process in the magnetization reversal of these structures