The study of topological defects has attracted much attention in these last years becoming an important subject of research in different fields of physics. Regarding this, in this talk a summary of the main examples of topological defects is given with emphasis on the discussion of topological properties of magnetic vortex. The distinction between vortex and antivortex topological configuration is highlighted on the basis of the well-known definition of topological charge and Pontryagin invariant. The significant symmetries of magnetic vortex are investigated. In particular, it is shown that the mirror reflection of a magnetic ring in the vortex-state in a plane perpendicular to the vortex plane acts like a symmetry transformation. By using graphical and mathematical arguments, it is demonstrated that the out-of-plane magnetization in the vortex core removes the core singularity breaking this symmetry transformation. By comparison, the behaviour of classical hydrodynamic vortex under the same mirror reflection is studied. Finally, the out-of-plane rotation of the magnetization in the core region of magnetic vortex developing in real systems is described as a topological phase transition.--Presentazione orale su INVITO by R. Zivieri - conferenza internazionale
Topological properties of magnetic vortex -- Presentazione orale su INVITO by R. Zivieri - Conferenza internazionale
ZIVIERI, Roberto
2010
Abstract
The study of topological defects has attracted much attention in these last years becoming an important subject of research in different fields of physics. Regarding this, in this talk a summary of the main examples of topological defects is given with emphasis on the discussion of topological properties of magnetic vortex. The distinction between vortex and antivortex topological configuration is highlighted on the basis of the well-known definition of topological charge and Pontryagin invariant. The significant symmetries of magnetic vortex are investigated. In particular, it is shown that the mirror reflection of a magnetic ring in the vortex-state in a plane perpendicular to the vortex plane acts like a symmetry transformation. By using graphical and mathematical arguments, it is demonstrated that the out-of-plane magnetization in the vortex core removes the core singularity breaking this symmetry transformation. By comparison, the behaviour of classical hydrodynamic vortex under the same mirror reflection is studied. Finally, the out-of-plane rotation of the magnetization in the core region of magnetic vortex developing in real systems is described as a topological phase transition.--Presentazione orale su INVITO by R. Zivieri - conferenza internazionaleI documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
