Scientists at Tohoku University in Japan have recorded data at a density of 4 trillion bits per square inch, which is a world record for the experimental "ferroelectric" data storage method. As described the journal Applied Physics Letters, which is published by the American Institute of Physics, this density is about eight times the density of today's most advanced magnetic hard-disk drives.
The data-recording device scans a tiny cantilever tip that rides in contact with the surface of a ferroelectric material. To write data, an electric pulse is sent through the tip, changing the electric polarization and nonlinear dielectric constant of a tiny circular spot in the substrate beneath. To read data, the same tip detects the variations in nonlinear dielectric constant in the altered regions.
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