IBM Engineers Atomic-Scale Memory

By Thor Olavsrud

It takes about one million atoms to store a single bit of information, unless you're a scientist with IBM Research. IBM (NYSE:IBM) scientists reported Thursday that they had successfully demonstrated the ability to store information in as few as 12 magnetic atoms.

"The chip industry will continue its pursuit of incremental scaling in semiconductor technology but, as components continue to shrink, the march continues to the inevitable end point: the atom," said Andreas Heinrich, the lead investigator into atomic storage at IBM Research, located in Almaden, Calif. "We're taking the opposite approach and starting with the smallest unit — single atoms — to build computing devices one atom at a time."

IBM has been engaged in nanotechnology research for 30 years. One of those areas of research has been in manipulating matter atom by atom to help us understand how to build smaller, faster and more energy efficient devices.

Thursday's breakthrough will likely take five to 10 years to develop into commercially viable storage, according to a statement made by Heinrich to Computerworld. But he said it does prove that storage media can be much denser than they are today.

The smallest chunk of information is a bit, which is essentially an on or off switch represented by a '1' or a '0'. A byte consists of eight bits, which historically was the number of bits required to encode a single text character on a computer. By reducing the number of atoms required to store a bit down to 12 from about one million, IBM said its experimental memory is at least 100 times denser than today's hard disk drives and solid-state memory chips.

Traditional magnetic data storage uses ferromagnetism — the same type of magnetism generated by household magnets you might find on your refrigerator — to align the spin of atoms in a single direction and determine whether they represent a '1' or a '0'. But IBM said a major obstacle for scaling this technology down to atomic dimensions is the interaction of neighboring bits with each other. The magnetic field of one bit can strongly affect its neighbor.

To avoid this problem, the IBM researchers used antiferromagnetism, in which the atoms are all aligned in such a way that the neighboring atoms spin in opposite directions. The scientists used a scanning tunneling microscope (STM) to atomically engineer a grouping of twelve antiferromagnetically coupled atoms. Because of their alternating magnetic spin directions, the scientists were able to pack the adjacent bits much more closely together than would have been possible with ferromagnetically coupled atoms without disrupting the state of neighboring bits.

One of the difficulties in developing the technology is that the antiferromagnetic order of the atoms can generally only be maintained at low temperatures — with the exact temperature determined by the substance used. The cut off is known as the Néel Temperature or magnetic ordering temperature. Above that temperature, the material becomes paramagnetic, a form of magnetism in which the material is only attracted when in the presence of an externally applied magnetic field. Computerworld noted that the IBM Research experiment was conducted at about 1 degree Kelvin (about -272 °C or -458 °F). At that temperature, the scientists were able to store a bit of information for hours.

Thor Olavsrud is a contributor to InternetNews.com, the news service of the IT Business Edge Network, the network for technology professionals.

This article was originally published on January 13, 2012