From The Niels Bohr Institute [Niels Bohr Institutet] (DK): “Scientists discovers new properties of magnetism that could change our computers”

Niels Bohr Institute bloc

From The Niels Bohr Institute [Niels Bohr Institutet] (DK)

at

University of Copenhagen [Københavns Universitet] [UCPH] (DK)

11 May 2022

Kim Lefmann
Professor
Condensed Matter Physics
Niels Bohr Institute
University of Copenhagen
Mail: lefmann@nbi.ku.dk
Phone: +45 29 25 04 76

Michael Skov Jensen
Journalist
Faculty of Science
University of Copenhagen
Mail: msj@science.ku.dk
Phone: +45 93 56 58 97

Physics-Our electronics can no longer shrink and are on the verge of overheating. But in a new discovery from the University of Copenhagen, researchers have uncovered a fundamental property of magnetism, which may become relevant for the development of a new generation of more powerful and less hot computers.

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Photo: Getty.

The ongoing miniaturization of components for computers which have electrons as their vehicles for information transfer has become challenged. Instead, it could be possible to use magnetism and thereby keep up the development of both cheaper and more powerful computers. This is one of the perspectives as scientists from the Niels Bohr Institute (NBI), University of Copenhagen, today publish a new discovery in the prestigious journal Nature Communications.

“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 acceleration

To grasp the discovery, one needs to know that magnetic materials are not necessarily uniformly oriented. In other words, areas with magnetic north and south poles may exist side by side. These areas are termed domains, and the border between a north and south pole domain is the domain wall. While the domain wall is not a physical object it nevertheless has several particle-like properties. Thereby, it is an example of what physicists refer to as quasi-particles, meaning virtual phenomena which resemble particles.

“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 objects 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.”

Swiss hypothesis provided inspiration

A similar phenomenon is seen for electrons. Here, it is known as Bloch oscillations named after the American-Swizz physicist and Nobel laureate Felix Bloch who discovered it in 1929. In 1996 Swiss theoretical physicists suggested that a parallel to Bloch oscillations could possibly exist in magnetism. Now – a little more than a quarter of a century later – Kim Lefmann and his colleagues managed to confirm this hypothesis. The research team has studied the movement of domain walls in the magnetic material CoCl2 ∙ 2D2O.

“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

Neutron sources are large-scale scientific instruments. Worldwide, only some twenty facilities exist and competition for beam time is fierce. Therefore, only now has the team managed to get enough data to satisfy the Nature Communications editors.

“We have had beam time at The National Institute of Standards and Technology 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 clarify, he emphasizes that even though quantum mechanics is involved, a computer based on magnetism would not be a type of 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.”

See the full article here .


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Niels Bohr Institute Campus

The Niels Bohr Institutet (DK) is a research institute of the Københavns Universitet [UCPH] (DK). The research of the institute spans astronomy, geophysics, nanotechnology, particle physics, quantum mechanics and biophysics.

The Institute was founded in 1921, as the Institute for Theoretical Physics of the Københavns Universitet [UCPH] (DK), by the Danish theoretical physicist Niels Bohr, who had been on the staff of the University of Copenhagen since 1914, and who had been lobbying for its creation since his appointment as professor in 1916. On the 80th anniversary of Niels Bohr’s birth – October 7, 1965 – the Institute officially became The Niels Bohr Institutet (DK). Much of its original funding came from the charitable foundation of the Carlsberg brewery, and later from the Rockefeller Foundation.

During the 1920s, and 1930s, the Institute was the centre of the developing disciplines of atomic physics and quantum physics. Physicists from across Europe (and sometimes further abroad) often visited the Institute to confer with Bohr on new theories and discoveries. The Copenhagen interpretation of quantum mechanics is named after work done at the Institute during this time.

On January 1, 1993 the institute was fused with the Astronomic Observatory, the Ørsted Laboratory and the Geophysical Institute. The new resulting institute retained the name Niels Bohr Institutet (DK).

Københavns Universitet (UCPH) (DK) is the oldest university and research institution in Denmark. Founded in 1479 as a studium generale, it is the second oldest institution for higher education in Scandinavia after Uppsala University (1477). The university has 23,473 undergraduate students, 17,398 postgraduate students, 2,968 doctoral students and over 9,000 employees. The university has four campuses located in and around Copenhagen, with the headquarters located in central Copenhagen. Most courses are taught in Danish; however, many courses are also offered in English and a few in German. The university has several thousands of foreign students, about half of whom come from Nordic countries.

The university is a member of the International Alliance of Research Universities (IARU), along with University of Cambridge (UK), Yale University , The Australian National University (AU), and University of California-Berkeley , amongst others. The 2016 Academic Ranking of World Universities ranks the University of Copenhagen as the best university in Scandinavia and 30th in the world, the 2016-2017 Times Higher Education World University Rankings as 120th in the world, and the 2016-2017 QS World University Rankings as 68th in the world. The university has had 9 alumni become Nobel laureates and has produced one Turing Award recipient.