A class of non-volatile memory devices, known as MRAM, based on quantum magnetic materials, can offer twice the performance of current modern memory devices. The materials, known as antiferromagnets, had previously been shown to store stable memory states, but they were difficult to read. This new study solves an efficient way to read the memory states, and it could be done very quickly too.
You can probably blink about four times a second. You could say that the frequency of this attenuation is 4 hertz (cycles per second). Imagine trying to blink 1 billion times a second, or at 1 gigahertz, it would be physically impossible for a human. But this is the current order of magnitude in which contemporary high-end digital devices, such as magnetic memory, change their states as operations are performed. And many people want to push the limit a thousand times further, into the trillion times per second, or terahertz, realm.
The materials used may be the barrier to achieving faster memory devices. Current high-speed MRAM chips, which are not yet commonly seen in your home computer, use typical magnetic, or ferromagnetic, materials. These are read using a technique called tunneling magnetism. This requires that the magnetic components of a ferromagnetic material be lined up in parallel arrangements. However, this arrangement creates a strong magnetic field that limits the speed at which the memory can be read or written to.
“We have made experimental progress that overcomes this limitation, and it is thanks to a different type of material, antiferromagnets,” said Professor Satoru Nakatsuji from the Department of Physics of the University of Tokyo. “Antiferromagnets differ from typical magnets in many ways, but in particular, we can arrange them in ways other than parallel lines. This means that we can negate the magnetic field that would result from parallel arrangements. Ferromagnets are thought to require magnetization. tunneling magnetoresistors to read from memory. Surprisingly, however, we discovered that a special class of antiferromagnets can exist without magnetization, and it is hoped that it can operate at very high speeds.”
Nakatsuji and his team think that it is possible to achieve transfer speeds in the terahertz range, and that this is also possible at room temperature, although previous efforts required much colder temperatures and did not give promising results . However, in order to improve her idea, the team needs to refine her devices, and it is crucial to improve the way she does them.
“While the atomic constituents of our material — manganese, magnesium, tin, oxygen, and so on — are very familiar — the way we combine them to create a usable memory component is novel and unfamiliar,” a researcher Xianzhe Chen said. “We are growing crystals in a vacuum, in extremely fine layers using two processes called molecular beam epitaxy and magnetron sputtering. The higher the vacuum, the purer the samples we can grow. It is a very procedure it’s challenging and if we improve it, we’ll make our lives easier and we’ll also produce more efficient devices.”
These antiferromagnetic memory devices take advantage of a quantum phenomenon known as entanglement, or interaction at a distance. But despite that, this research is not directly related to the increasingly famous field of quantum computing. However, researchers suggest that such developments may be useful or even necessary to build a bridge between the current paradigm of electronic computing and the emerging field of quantum computers.