Extra twist in magnetic bubbles.

Abstract

In the hard disk of a computer, the memory is stored in the local direction of the magnetization of a magnetic alloy. Here, just two directions of the magnetization (e.g., parallel and antiparallel to the disk) are used. Magnets can, however, form much more complex structures. Examples are bubble domains (1), where in thin magnetic layers, a regular arrangement of magnetic bubbles is induced by small magnetic fields. In PNAS, the work by Yu et al. (2) uses EM to reveal the local orientation of the magnetization in magnetic bubbles and stripes. The magnetization shows surprising twists: instead of rotating always in one direction, it twists back and forth. Such twist may be important for the manipulation of magnetism by electric currents and electric fields.