Probing the local magnetization reversal through magnetoresistance measurement.

A microstructured permalloy ellipse with six equally spaced nonmagnetic voltage leads has been studied through magnetoresistance measurements and magnetic force microscopy. The aspect ratio and film thickness of the element having three vortices of magnetic configuration were accordingly designed and fabricated using electron-beam lithography through a lift off process. Magnetoresistance curves measured with various pairs of voltage leads have revealed a local magnetic-moment reversal. Two magnetoresistance kinks observed with decreasing/increasing field strength can be attributed to the vortex formation/annihilation, which was confirmed by magnetic force microscopy and micromagnetic simulation. The motion of the vortex core driven by the transverse external magnetic field was estimated to be 4.1 nm/Oe. [ABSTRACT FROM AUTHOR]