1 research outputs found
Halfvortices in flat nanomagnets
We discuss a new type of topological defect in XY systems where the O(2)
symmetry is broken in the presence of a boundary. Of particular interest is the
appearance of such defects in nanomagnets with a planar geometry. They are
manifested as kinks of magnetization along the edge and can be viewed as
halfvortices with winding numbers \pm 1/2. We argue that halfvortices play a
role equally important to that of ordinary vortices in the statics and dynamics
of flat nanomagnets. Domain walls found in experiments and numerical
simulations are composite objects containing two or more of these elementary
defects. We also discuss a closely related system: the two-dimensional smectic
liquid crystal films with planar boundary condition.Comment: 7 pages, 8 figures, To appear as a chapter in Les Houches summer
school on Quantum Magnetis