Probing the magnetization reversal of microstructured permalloy cross by planar hall measurement and magnetic force microscopy

摘要

Over the last decade, intense efforts in not only experiments but also theoretical models to investigate macroscopic quantum tunneling of magnetic domain wall have been reported in a variety of magnetic systems, such as nanowires, nanoconstrictions, ferromagnetic rings with notches, and NiFe/Gd/NiFe sandwiched structure. What have been found is that the presence of a domain wall and its subsequent removal by the application of a sufficient external magnetic field give rise to a resistance change, but a controversy remained regarding to the sign of domain wall contributed to the resistance change, namely positive or negative magnetoresistance effect. Direct experimental evidences are therefore pressingly required. Herein, we investigate the magnetization reversal at the junction of a single layer microstructured permalloy cross via magnetoresistance measurement, planar Hall measurement, and magnetic force microscope (MFM) to get further experimental evidences and thus try to clarify the aforementioned controversial issue.