In a continuous ultrathin film with thickness smaller than the so-called exchange length all the magnetic spins are held together by the exchange forces. Typically the exchange length is around 5-10 nm in ferromagnetic transition metals. Provded the film thickness is much smaller than the lateral dimensions, the lowest stable energy state is a single domain state in which all the spins lie parallel and in the plane of the film. One possible approach to circumventing the superparamagnetic limit in conventional media is to use patterned media in which each element is a magnetic dot arranged in a periodic array and which has a thickness of a few atomic layers. Such structures will remain stable down to much lower lateral dimensions than conventional bits in continuous media. Research is now focusing on the spin configurations and dynamics of such magnetic nanostructures.
There are currently no criteria on which to search. Please add them using the 'criteria' tab.