Note: The IBM atomic storage story starts at the 8:05 minute mark. There is also a story on IBM Quantum Computing at the 26:07 minute mark.
Today IBM announced it has created the world’s smallest magnet using a single atom – and stored one bit of data on it. Currently, hard disk drives use about 100,000 atoms to store a single bit. The ability to read and write one bit on one atom creates new possibilities for developing significantly smaller and denser storage devices, that could someday, for example, enable storing the entire iTunes library of 35 million songs on a device the size of a credit card. Today’s breakthrough builds on 35 years of nanotechnology history at IBM, including the invention of the Nobel prize-winning scanning tunneling microscope.
Magnetic bits lie at the heart of hard-disk drives, tape and next-generation magnetic memory,” said Christopher Lutz, lead nanoscience researcher at IBM Research – Almaden in San Jose, California. “We conducted this research to understand what happens when you shrink technology down to the most fundamental extreme — the atomic scale.”
By starting at the smallest unit of common matter, the atom, scientists demonstrated the reading and writing of a bit of information to the atom by using electrical current. They showed that two magnetic atoms could be written and read independently even when they were separated by just one nanometer – a distance that is only a millionth the width of a pin head. This tight spacing could eventually yield magnetic storage that is 1,000 times denser than today’s hard disk drives and solid state memory chips. Future applications of nanostructures built with control over the position of every atom could allow people and businesses to store 1,000 times more information in the same space, someday making data centers, computers and personal devices radically smaller and more powerful.
The study was published today in the peer-reviewed journal, Nature.
How it Works
The most basic piece of information that a computer understands is a bit. Much like a light that can be switched on or off, a bit can have only one of two values: “1” or “0”. Until now, it was unknown how few atoms it would take to build a reliable magnetic memory bit.
The world’s smallest magnet, similar to a magnet on a refrigerator, also has a north and south magnetic pole, but it consists of just a single atom of the element holmium. The single holmium atom is attached to a carefully chosen surface, magnesium oxide, which makes its north and south poles hold in a stable direction even when disturbed, for example, by other magnets nearby. The two stable magnetic orientations define the “1” and “0” of the bit. A sharp metal needle of a custom microscope introduces a current that flips the magnetic north and south poles of the atom and thus changes it between “1” and “0”. This corresponds to the “write” process in a hard-disk drive. Scientists can then measure the magnetic current passing though the atom to determine whether its value is “1” or “0”. This is the “read” process. More about the atom’s magnetic properties was learned using a new sensing technique introduced in a companion paper published earlier this week in the peer-reviewed journal, Nature Nanotechnology. The quantum mechanical technique called “spin resonance” allowed the researchers to use a single iron atom as a sensor to measure the magnetic field of each holmium atom.
It doesn’t get any smaller than a single atom. This is the ultimate storage feat – one bit on one magnetic atom. We’re excited about the potential for dramatically different storage that’s more compact and robust than anything we’ve previously seen,” said Dr. Andreas Heinrich, scientist for the Institute of Basic Science (IBS) in Korea and former IBM Research scientist.
The scientists at IBM Research used a scanning tunneling microscope (STM), an IBM invention that won the 1986 Nobel Prize for Physics, to build and measure isolated single-atom bits using the holmium atoms. The custom microscope operates in extreme vacuum conditions to eliminate interference by air molecules and other contamination. The microscope also uses liquid helium for cooling that allows the atoms to retain their magnetic orientations long enough to be written and read reliably.
Implications for Quantum
Earlier this week, IBM Research announced it will be building the world’s first commercial quantum computers for business and science. Future scanning tunneling microscope studies will investigate the potential of performing quantum information processing using individual magnetic atoms.
IBM and Nanotechnology Leadership
During 35 years of nanotechnology research, IBM has achieved a number of milestones, including the invention of the Nobel prize-winning scanning tunneling microscope capable of imaging individual atoms, positioning atoms one-by-one for the first time and incorporating sub-nanometer material layers into hard-disk drive recording heads and magnetic-disk coatings.
IBM Research Frontiers Institute
Nanoscopes, like the scanning tunnel microscope used in this study, are a key area of focus for the IBM Research Frontiers Institute, a global research consortium focused on developing groundbreaking computing technologies. For more information on joining RFI, please click here.