Investigation of ferromagnetic microstructures by local Hall effect and magnetic force microscopy

We have investigated the magnetization process of NiFe micro-magnets, using fringing field induced local Hall effect (LHE) and magnetic force microscopy (MFM), Although the LHE reflects information only from the edge of micro-magnets, the MFM observation supports the conclusion that a rapid jump in the Hall resistance implies a sharp switching of the magnetization. The width dependence of coercive field H-c for NiFe micro-magnets obtained from LHE measurement is well reproduced by numerical calculations. The good agreement between the LHE experiment and the model calculation shows that a LHE device provides useful information on the magnetization process in micro-magnets.