By Peter Weiss
The data capacity of a computer’s magnetic hard drive depends largely on the sensitivity of a detector, or read head, that’s used to decipher its contents. Scientists have now exploited a method for detecting the orientations of magnetic fields to achieve a remarkable leap in sensitivity.
In the surface of a hard drive’s spinning disk lie tiny magnetized regions, or domains, whose magnetic field orientations represent either a 1 or a 0. As domains pass beneath it, a head responds to the changes in the magnetic field orientations with variations in its electrical resistance.