Chirality control of magnetic vortex in a square Py dot using current-induced Oersted field

We have proposed a method for controlling the vortex chirality in a squared permalloy dot by using the circular Oersted field locally induced by flowing a DC current across a small Py/Cu junctions. The reliability of the chirality control has been evaluated by measuring the nonlocal spin valve signal. The desired vortex chirality has been obtained when the injecting DC current has a moderate magnitude. However, the large DC current is found to reduce the control reliability. Another possibility for controlling the vortex structure using the large DC current injection was also discussed. (C) 2011 American Institute of Physics. [doi:10.1063/1.3669410]