Our devices are on the edge of overheating because they can no longer shrink. However, researchers at the University of Copenhagen have discovered a fundamental property of magnetism that could be useful in the development of a new generation of more powerful and cooler computers.
The continuous downsizing of computer components that use electrons as their means of data transfer has become a problem. Instead, magnetism might be used to keep the development of both cheaper and more powerful computers moving forward.
This is one of the ideas presented today in the journal Nature Communications by scientists from the Niels Bohr Institute (NBI) at the University of Copenhagen.
“The function of a computer involves sending electric current through a microchip. While the amount is tiny, the current will not only transport information but also contribute to heating up the chip. When you have a huge number of components tightly packed, the heat becomes a problem. This is one of the reasons why we have reached the limit for how much you can shrink the components. A computer-based on magnetism would avoid the problem of overheating,” says Professor Kim Lefmann, Condensed Matter Physics, NBI.
“Our discovery is not a direct recipe for making a computer-based on magnetism. Rather we have disclosed a fundamental magnetic property which you need to control, if you want to design a such computer.”
Quantum mechanics halt the acceleration
To understand the discovery, one must first understand that magnetic materials are not always uniformly aligned. To put it another way, places with magnetic north and south poles may coexist. Domains are the boundaries between these places, and the domain wall is the boundary between a north and south pole domain.
Despite the fact that the domain wall is not a real thing, it possesses some particle-like qualities. As a result, it is an example of quasi-particles, or virtual phenomena that resemble particles, as defined by physicists.
The function of a computer involves sending electric current through a microchip. While the amount is tiny, the current will not only transport information but also contribute to heating up the chip. When you have a huge number of components tightly packed, the heat becomes a problem. This is one of the reasons why we have reached the limit for how much you can shrink the components. A computer-based on magnetism would avoid the problem of overheating.
Professor Kim Lefmann
“It is well established that one can move the position of the domain wall by applying a magnetic field. Initially, the wall will react similarly to a physical object which is subjected to gravity and accelerates until it impacts the surface below. However, other laws apply to the quantum world,” Kim Lefmann explains.
“At the quantum level, particles are not only objected they are also waves. This applies to a quasi-particle such as a domain wall as well. The wave properties imply that the acceleration is slowed down as the wall interacts with atoms in the surroundings. Soon, the acceleration will stop totally, and the position of the wall will start to oscillate.”
Swizz hypothesis provided inspiration
Electrons exhibit a similar behaviour. Bloch oscillations are the name given to it in honor of American-Swiss physicist and Nobel laureate Felix Bloch, who discovered it in 1929. In 1996, Swiss theoretical physicists proposed that magnetism might have a connection to Bloch oscillations.
Kim Lefmann and his colleagues were able to test this notion a little more than a quarter of a century later. The mobility of domain walls in the magnetic substance CoCl2 ∙ 2D2O was explored by the study team.
“We have known for a long time, that it would be possible to verify the hypothesis, but we also understood that it would require access to neutron sources. Uniquely, neutrons react to magnetic fields despite not being electrically charged. This makes them ideal for magnetic studies,” Kim Lefmann tells.
Boost for research in magnetics
Large-scale scientific devices, and neutron sources are. Only about twenty facilities exist worldwide, and competition for beam time is strong. As a result, the team has only now been able to collect enough data to satisfy the editors of Nature Communications.
“We have had beam time at NIST in USA, and ILL in France respectively. Fortunately, the conditions for magnetic research will improve greatly as the ESS (European Spallation Source, ed.) becomes operational in Lund, Sweden. Not just will our chances for beam time become better, since Denmark is a co-owner of the facility. The quality of the results will become roughly 100 times better because the ESS will be an extremely powerful neutron source,” says Kim Lefmann.
To be clear, he adds that, despite the fact that quantum mechanics is involved, a computer-based on magnetism is not a quantum computer:
“In the future, quantum computers are expected to be able to tackle extremely complicated tasks. But even then, we will still need conventional computers for the more ordinary computing. This is where computers based on magnetism might become relevant alternatives as better than current computers.”
