Tuesday, January 17, 2012

World's smallest hard drive built of atoms

Can this small hard drive be of use to store terabytes of data in such a small storage unit? Can this be a portable one? Lets find the answer to all these questions!!!.

                                                         
Scientists from IBM and the German Center for Free-Electron Laser Science (CFEL) have built the world's smallest magnetic data storage unit. It uses just twelve atoms per bit, the basic unit of information, and squeezes a whole byte (8 bit) into as few as 96 atoms. A modern hard drive, for comparison, still needs more than half a billion atoms per byte.
 The nanometre data storage unit was built atom by atom with the help of a scanning tunneling microscope (STM) at IBM's Almaden Research Center in San Jose, California. The researchers constructed regular patterns of iron atoms, aligning them in rows of six atoms each. Two rows are sufficient to store one bit. A byte correspondingly consists of eight pairs of atom rows. It uses only an area of 4 by 16 nanometres (a nanometre being a millionth of a millimetre). This corresponds to a storage density that is a hundred times higher compared to a modern hard drive.Data are written into and read out from the nano storage unit with the help of an STM. The pairs of atom rows have two possible magnetic states, representing the two values '0' and '1' of a classical bit. An electric pulse from the STM tip flips the magnetic configuration from one to the other. A weaker pulse allows to read out the configuration, although the nano magnets are currently only stable at a frosty temperature of minus 268 degrees Centigrade (5 Kelvin). The researchers expect arrays of some 200 atoms to be stable at room temperature. Still it will take some time before atomic magnets can be used in data storage.


 The researchers,for the first time have managed to employ a special form of magnetism for data storage purposes, called antiferromagnetism. These antiferromagnetism materials, can be used in conventional hard drives, the spins of neighbouring atoms within antiferromagnetic material are oppositely aligned, rendering the material magnetically neutral on a bulk level. This means that antiferromagnetic atom rows can be spaced much more closely without magnetically interfering with each other. Thus, the scientist managed to pack bits only one nanometre apart. Twelve atoms emerged as the minimum with the elements used. Beneath this threshold quantum effects blur the stored information. If these quantum effects can somehow be employed for an even denser data storage is currently a topic of intense research.
With their experiments the team has not only built the smallest magnetic data storage unit ever, but have also created an ideal testbed for the transition from classical to quantum physics. They have learned to control quantum effects through form and size of the iron atom rows, The researchers can now use this ability to investigate how quantum mechanics kicks in. 

What separates quantum magnets from classical magnets? How does a magnet behave at the frontier between both worlds? These are exciting questions that soon could be answered as suggested by the scientists.Indeed scientists will bw able to find an answer to these questions very soon, and till then, we can hope that they do it sooner.
[via: Physorg]

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