Shrinking memory bits a million times through antiferromagnetically coupled atoms

Punctuating 30 years of nanotechnology research, scientists from IBM Research have successfully demonstrated the ability to store information in as few as 12 magnetic atoms. This is significantly less than today's disk drives, which use about one million atoms to store a single bit of information.

 
While silicon transistor technology has become cheaper, denser and more efficient, fundamental physical limitations suggest this path of conventional scaling is unsustainable. Alternative approaches are needed to continue the rapid pace of computing innovation. By taking a novel approach and beginning at the smallest unit of data storage, the atom, scientists demonstrated magnetic storage that is at least 100 times denser than today’s hard disk drives and solid state memory chips. Future applications of nanostructures built one atom at a time, and that apply an unconventional form of magnetism called antiferromagnetism, could allow people and businesses to store 100 times more information in the same space.

“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. We’re taking the opposite approach and starting with the smallest unit -- single atoms -- to build computing devices one atom at a time.” said Andreas Heinrich, the lead investigator into atomic storage at IBM Research – Almaden, in California.
 

The scientists at IBM Research used a scanning tunneling microscope (STM) to atomically engineer a grouping of twelve antiferromagnetically coupled atoms that stored a bit of data for hours at low temperatures. Taking advantage of their inherent alternating magnetic spin directions, they demonstrated the ability to pack adjacent magnetic bits much closer together than was previously possible. This greatly increased the magnetic storage density without disrupting the state of neighboring bits.

The challenge of Moore's Law
We expect our hard drives to store more and cost less every few years. But by current conventions the technology industry is reaching the physical limits of its faithful adherence to Moore's Law, which says that the number of transistors on a microchip will approximately double every two years.
To continue to advance, new methods were needed to pack more data storage and computing capabilities into smaller spaces.
The world's smallest bit
Scientists from IBM Research have been investigating and controlling matter on an atomic scale for decades. So, naturally, their latest quest would involve greatly decreasing the storage capacity needed for one bit of data, which on today's computers stands at about 1 million atoms.
They set out to develop the ultimate memory chips of the future. Starting at the very beginning of density—single atoms—they created the world’s smallest magnetic memory bit and answered the question of how many atoms it takes to reliably store one bit of magnetic information at a low temperature: 12.
By studying the behavior of atoms, researchers can identify crucial factors for building smaller, faster and more energy-efficient devices for business and consumers.