Dance of the domains

In a ferromagnet regions exist where all the atoms orient their atomic compass neddles into one direction. These regions are called domains. A recent experiment succeeded in exciting such domains and watching their vibration and subsequent relaxation to the original state. This is the Dance of the domains. Such processes happen extremly fast, taking on the order of a few hundered picoseconds (ps), or half of a billionth of a second. The experiment showed that even in a structure as simple as a square there are three different excitations, which are associated with the domain, the walls seperating two domains and the vortex, created at the intersection of two domains. It was possible to analyze all of these processes quantitativly and determine the frequencies. Fortunately the frequencies are high, several GHz. The domains dance at a high beat, which is important in every day life, because these domains are used to store information on the hard-disk of your PC, and the faster the beat, the faster a PC can store data.

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