'3-D towers' of information double data storage capacity

Posted by David Gomez

A research team in France has figured out how to double the areal density of information.

They did this by using a familiar form of patterned media; they basically cut the magnetic media into tiny pieces and built a “3D tower” out of it.
    
For those unfamiliar with the term areal density, it’s a computer science term that PC Mag.com’s IT encyclopedia defines as: The number of bits per square inch of storage surface. It typically refers to disk drives, where the number of bits per inch (bpi) times the number of tracks per inch (tpi) yields the areal density (didn’t know that).
    
The 3D data tower impressively increases the amount of data that can be stored in a magnetic storage device and gives the IT industry a method to reach beyond a wall of physical limits the technology is currently hitting. The research team presents their findings in the American Institute of Physics' Journal of Applied Physics.
    
"Over the past 50 years, with the rise of multimedia devices, the worldwide Internet, and the general growth in demand for greater data storage capacity, the areal density of information in magnetic hard disk drives has exponentially increased by 7 orders of magnitude," says Jerome Moritz, a researcher at SPINTEC, in Grenoble. "This areal density is now about 500Gbit/in2, and the technology presently used involves writing the information on a granular magnetic material. This technology is now reaching some physical limits because the grains are becoming so small that their magnetization becomes unstable and the information written on them is gradually lost."
    
Thus, new tactics are needed for magnetic data storage densities exceeding 1Tbit/in2.
    
"Our new approach involves using bit-patterned media, which are made of arrays of physically separated magnetic nanodots, with each nanodot carrying one bit of information. To further extend the storage density, it's possible to increase the number of bits per dots by stacking several magnetic layers to obtain a multilevel magnetic recording device," explains Moritz.
    
With that framework, Moritz and coworkers were able to establish that the best way to achieve a 2-bit-per-dot media involves stacking in-plane and perpendicular-to-plane magnetic media atop each dot. The perpendicularly magnetized layer can be read right above the dot, while the in-plane magnetized layer can be read between dots. This permits doubling of the areal density for a given dot size by taking better advantage of the whole patterned media area.
    
You know the drill, this is an awesome development, but the journal article is behind an academic pay wall. Here’s the journal’s website for those of you who can access it and want to read it.  

Information provided by American Association for the Advancement of Science: EurekAlert!