Scientists showed for the first time the presence of unique magnetic transitions in peculiar structures similar to quasicrystals
In the world of materials science, many have heard of crystals, highly ordered structures in which atoms are arranged in a tight and periodic manner (in which the atomic arrangement is repeated).
But, not many people know about quasicrystals, which are unique structures with strange atomic arrangement. Like crystals, quasicrystals are also tightly arranged, but what's different about them is the fact that they possess an unprecedented pentagonal symmetry, such that the atomic arrangement is highly ordered but not periodic.
This distinctive feature gives them unique properties, like high stability, resistance to heat, and low friction. Since their discovery only about 30 years ago, scientists globally have been trying to understand the properties of quasicrystals, in an effort to make more advancements in materials research. But, this is not easy, as quasicrystals are not prevalent in nature.
Luckily, they have been able to make use of structures similar to quasicrystals, called "Tsai-type approximants." Understanding these structures in detail could give insights into the many properties of quasicrystals.
One such property is antiferromagnetism, in which magnetic moments are aligned in a quasiperiodic order, strikingly distinguished from conventional antiferromagnets. This property has never been observed in quasicrystals so far, but the possibility was exciting for materials scientists, as it could be a gateway to a plethora of new applications.
In a new study published in Physical Review B: Rapid Communications, a team of scientists at Tokyo University of Science, led by Prof Ryuji Tamura, found for the first time that a type of Tsai-type approximant exhibits an antiferromagnetic transition. This was an exciting finding, as it suggested that even quasicrystals could show such a transition. The scientists already knew that Tsai-type approximants have two different variants: 1/1 and 2/1 approximants.
The main difference between the two is that 2/1 approximants contain an additional rhombohedral unit in their structure, which is absent in the 1/1 type, making them even more highly ordered and closer to the structure of quasicrystals. And, this is why the scientists wanted to see the conditions in which 2/1 approximants could show antiferromagnetism; it created a possibility of seeing this new property even in quasicrystals.
Prof Tamura says, "Antiferromagnetic transitions have been observed in 1/1 approximants, but we observed it in a 2/1 approximant for the first time. This is interesting because unlike the 1/1 approximant, the 2/1 approximant contains all the components necessary to construct a quasicrystal."
To take a closer look at the magnetic properties of 2/1 approximants, the scientists synthesized metallic alloys with a crystalline structure, which contained both 1/1 and 2/1 approximants. By using a device called the superconducting quantum interference device (SQUID), they studied the conditions under which the approximants showed different magnetic properties.
Interestingly, they found that a single parameter dictates the presence of antiferromagnetism in both types of approximants. This was the ratio of electron per atom, which slightly differed in the two types. By manipulating the electron-per-atom ratio, Prof Tamura and his team saw a "transition" to an antiferromagnetic state in both types of approximants.
This property had been seen in the 1/1 type before but never in the 2/1 approximant. This was an exciting development, as the highly ordered structure of the 2/1 approximant meant that it could be used to generate quasicrystals, making this the very first study to show the possibility of antiferromagnetic quasicrystals.
Elaborating on their findings, Prof Tamura says, "We succeeded in observing, for the first time, antiferromagnetic transitions in the 1/1 and 2/1 AFM approximants in the same alloy system." He adds, "Our finding clearly shows that the antiferromagnetic order survives in the 2/1 higher-order approximant, which has all the building blocks for creating a quasicrystal."
The significance of quasicrystals--such as in routine applications like making frying pans and needles for acupuncture and surgery--is well known. But, given their very recent discovery, not much has been understood about what makes them so unique.
By showing the existence of antiferromagnetism in a quasicrystal-like structure, Prof Tamura and his team have potentially paved the way for greater developments in quasicrystal research. Prof Tamura concludes by saying, "Antiferromagnetic quasicrystals had never been seen before, and this discovery has a great academic impact." He adds, "The possibility of the existence of antiferromagnetic quasicrystals is a big step towards deciphering the mystery of quasicrystals."
About The Tokyo University of Science
Tokyo University of Science (TUS) is a well-known and respected university, and the largest science-specialized private research university in Japan, with four campuses in central Tokyo and its suburbs and in Hokkaido. Established in 1881, the university has continually contributed to Japan's development in science through inculcating the love for science in researchers, technicians, and educators.
With a mission of "Creating science and technology for the harmonious development of nature, human beings, and society," TUS has undertaken a wide range of research from basic to applied science. TUS has embraced a multidisciplinary approach to research and undertaken intensive study in some of today's most vital fields. TUS is a meritocracy where the best in science is recognized and nurtured. It is the only private university in Japan that has produced a Nobel Prize winner and the only private university in Asia to produce Nobel Prize winners within the natural sciences field.
About Professor Ryuji Tamura from Tokyo University of Science
Dr Ryuji Tamura is a Professor in the Department of Materials Science and Technology at Tokyo University of Science, Japan. A respected and senior researcher, he has more than 140 research publications to his credit. He is also the corresponding author of this study. His chief areas of interests include the study of hypermaterials such as quasicrystals and approximants. His research can be found at https:/
This study was funded by the Kakenhi Grant-in-Aid for Scientific Research on Innovative Areas "Hypermaterials: Innovation of materials science in hyper space, Head Investigator: Prof Ryuji Tamura" for FY 2019-23 (grant number JP19H05818) by the Ministry of Education, Culture, Sports, Science, and Technology.
Tsutomu Shimizu | EurekAlert!
Tiny quantum sensors watch materials transform under pressure
13.12.2019 | DOE/Lawrence Berkeley National Laboratory
Light, strong, and tough: Researchers at the University of Bayreuth discover unique polymer fibres
13.12.2019 | Universität Bayreuth
Vaccinia viruses serve as a vaccine against human smallpox and as the basis of new cancer therapies. Two studies now provide fascinating insights into their unusual propagation strategy at the atomic level.
For viruses to multiply, they usually need the support of the cells they infect. In many cases, only in their host’s nucleus can they find the machines,...
More than one hundred and fifty years have passed since the publication of James Clerk Maxwell's "A Dynamical Theory of the Electromagnetic Field" (1865). What would our lives be without this publication?
It is difficult to imagine, as this treatise revolutionized our fundamental understanding of electric fields, magnetic fields, and light. The twenty original...
In a joint experimental and theoretical work performed at the Heidelberg Max Planck Institute for Nuclear Physics, an international team of physicists detected for the first time an orbital crossing in the highly charged ion Pr⁹⁺. Optical spectra were recorded employing an electron beam ion trap and analysed with the aid of atomic structure calculations. A proposed nHz-wide transition has been identified and its energy was determined with high precision. Theory predicts a very high sensitivity to new physics and extremely low susceptibility to external perturbations for this “clock line” making it a unique candidate for proposed precision studies.
Laser spectroscopy of neutral atoms and singly charged ions has reached astonishing precision by merit of a chain of technological advances during the past...
The ability to investigate the dynamics of single particle at the nano-scale and femtosecond level remained an unfathomed dream for years. It was not until the dawn of the 21st century that nanotechnology and femtoscience gradually merged together and the first ultrafast microscopy of individual quantum dots (QDs) and molecules was accomplished.
Ultrafast microscopy studies entirely rely on detecting nanoparticles or single molecules with luminescence techniques, which require efficient emitters to...
Graphene, a two-dimensional structure made of carbon, is a material with excellent mechanical, electronic and optical properties. However, it did not seem suitable for magnetic applications. Together with international partners, Empa researchers have now succeeded in synthesizing a unique nanographene predicted in the 1970s, which conclusively demonstrates that carbon in very specific forms has magnetic properties that could permit future spintronic applications. The results have just been published in the renowned journal Nature Nanotechnology.
Depending on the shape and orientation of their edges, graphene nanostructures (also known as nanographenes) can have very different properties – for example,...
03.12.2019 | Event News
15.11.2019 | Event News
15.11.2019 | Event News
13.12.2019 | Physics and Astronomy
13.12.2019 | Physics and Astronomy
13.12.2019 | Materials Sciences