MAGNETIC VORTEX BEHAVIOR IN NANO-STRUCTURES
The existence of a vortex in the ground state of magnetic nano-disks has open a wide range of possibilities for constructing new ultra-compact devices. In this work we study the dynamical behavior of a vortex in a magnetic nano-particle. First, we introduce magnetic impurities in the system. It is observed that depending on the strength of the interaction the impurities can behave both as a pinning (attractive) or scattering (repulsive). By using the known values of the parameters for Permalloy-79 we have calculated the interaction energy of the vortex core with a single defect. We estimated the interaction range as approximately 10 nm. Both results agree quite well with experimental measurements. As a second point we discuss how the vortex dynamics in nano-disks can be used for building a nano-spin valve.