Vertical bistable switching of spin vortex in a circular magnetic dot

We have investigated switching behaviors of a spin-vortex core in circular magnetic dots to evaluate them as a new candidate for magnetic memory elements. The spin-vortex core with the lateral dimension of exchange length can take two possible states with spins around the dot center directing either up- or downward. These two spin configurations are very stable and their polarities can be switched by a large vertical field. The mean switching field reaches about 2.5 kOe for Ni80Fe20 dots with 1 mum in diameter and 80 nm in height. This result could open the way for developing a new bistable magnetic memory element utilizing the spin vortex. (C) 2001 American Institute of Physics.