superparamagnetic limit


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superparamagnetic limit

The maximum number of bits per square inch that is commercially feasible on a magnetic storage device. As the magnetic bits get smaller, at some point they no longer hold their charge. Thermal fluctuations reduce the signal strength and render the bits unstable.

However, this maximum density limit keeps changing as researchers find new techniques for recording and sensing the bit. Years ago the limit was thought to be 20 gigabits per square inch. Today, we are already beyond a terabit per square inch. See areal density, perpendicular recording, magnetoresistance and AFC.
References in periodicals archive ?
In the near term, data-storage density will continue to shrink, despite the impending superparamagnetic limit. To push that evolution as far as possible, Seagate, for one, has set out a road map for improving data density over the next decade.
Beyond the superparamagnetic limit II: Far-field recording.
Data densities beyond the superparamagnetic limit have been postulated at the Massachusetts Institute of Technology (Cambridge, MA).
The future of magnetic disk-drive storage hinges on surpassing the superparamagnetic limit.
This superparamagnetic limit thus drives up the grain size and keeps it above 10 nm.
The answer is a qualified "yes." There is a limit called the superparamagnetic limit. When this point is reached, there simply are not enough atoms, enough mass, in a magnetic domain to remain stable at room temperature.
In addition, the "superparamagnetic limit," that is, the conflict between reducing the magnetic energy barrier and decreasing the size, restrains the development of [Fe.sub.3][O.sub.4] nanomaterials [9].