Vortex Dynamics in Ferromagnetic Nanoelements Observed by Micro-Hall Probes

In this work we measure the nucleation and annihilation of magnetic vortices in Pacman-like (PL) micromagnets prepared from Permalloy ($Ni_{81}Fe_{19}$, Py) at 77 K. Lateral dimensions of explored objects are ≤1 μm with thickness of about 40 nm. The micromagnets are located directly on the high-sensitive micro-Hall probe based on GaAs/AlGaAs heterostructure by lift-off process. Experiments show good agreement of the magnetization reversal with the micromagnetic simulation. Other shapes of micromagnets are also considered to obtain more precise picture of the vortex dynamics.