EPFL Physicists are pushing forward research into single-atom data storage, a far superior alternative to current data storage solutions.
Conventional storage media like hard drives and magnetic oxide tapes that rely on magnetism to store data are still the main form of data storage in use in the world today.
Since the mid-2000s, however, solid-state storage solutions like flash memory sticks started to take center stage.
Having no mechanical parts like hard disk drives, solid-state devices (SSDs) are an assembly of memory chips on a circuit which makes them less prone to heat and stores media more efficiently.
However, even SSDs can’t keep up with Big Data and the ever-increasing data storage needs, estimated to expand by around 15 million gigabytes every day.
Now, however, Swiss researchers may have found a solution.
Single-Atom Magnets: “Bits” of Magnets to Store Data Bits
Per quantum physics and the principles of quantum computing, a single atom can store a single bit of readable data.
There are a few things in nature smaller than an atom. Theoretically, you can pack millions of atoms on a tiny chip that could provide an unprecedented level of data storage density.
That means a 1 million-atom chip would be able to store one megabit of data. If you think this is nothing, let’s take current hard disk drives as an example.
In comparison, a hard disk uses the same amount of atoms (1 million) to write and read one bit of data. In fact, you could say that the data density increase would be by a factor of one million.
Research into single-atom magnets is still in its infancy, but it is certainly a feasible future solution.
Physicists at The École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland have been pioneering single-atom data storage research for years.
Basically, scientists take a magnet and keep chopping it until they get magnetic single atoms which they then pack together on a chip.
However, at the atom level, many problems arise as magnet atoms can become unstable and tend to flip the polarity of their magnetic fields.
In 2016, EPFL researchers managed to overcome the magnetic remanence issue and created a stable single-atom magnet.
Then, in 2017, they were the first, with collaboration from IBM, to demonstrate how single-atom magnets can be used to store and read data.
Holmium Atomic Hard Drives
Now, this year, the research team is making yet another step toward making single-atom magnets stable enough to be used as reliable storage devices.
A research team at EPFL’s Institute of Physics have been working on holmium as a potential material for single-atom magnets used for data storage and retrieval.
A rare-earth element, holmium is the most powerful of all magnetic elements and is used in a number of research projects like CERN’s Large Hadron Collider.
The research team exposed the holmium atoms to high temperatures and high magnetic fields, which usually would result in the demagnetization of single-atom magnets.
Upon investigation, using a Scanning Tunneling Microscope, the team found that the holmium atoms didn’t lose any of their magnetization.
Even when subjected to a magnetic field nearing that generated by the Large Hadron Collider’s powerful magnets (over 8 Tesla), holmium atoms retained their magnetization.
“Coercivity” is the term physicists give to the ability of ferromagnetic materials to maintain their magnetization despite the action of an external magnetic field.
The EPFL team described its achievement as a “record-breaking coercivity”.
For heat, researchers kept going up until the magnetic bits of holmium started demagnetizing at around 45 Kelvin (-233.15 degrees C), which for a single atom is like sitting in a sauna for a human.
“Research in the miniaturization of magnetic bits has focused heavily on magnetic bistability,” said Fabian Natterer, the study’s first author. “We have demonstrated that the smallest bits can indeed be extremely stable, but next we need to learn how to write information to those bits more effectively to overcome the magnetic ‘trilemma’ of magnetic recording: stability, writability, and signal-to-noise ratio.”
Single-atom data storage devices pick up more steam with each of EPFL’s breakthrough, and we’ll be waiting for their next achievement.
At 1.2 parts per million by weight of the earth’s crust, 100g of pure holmium costs $860. This may become an issue in the future with scalability, but that is an issue for after the egg of single-atom data storage has been cracked.