Researchers have discovered antiferromagnetism in a gold-indium-europium icosahedral quasicrystal (iQC), marking the first direct observation of this magnetic order in real QCs. The discovery, led by Ryuji Tamura and team, opens new possibilities for energy-efficient technologies in spintronics and magnetic refrigeration, aligning with sustainable development goals.
In a pioneering breakthrough, researchers have unveiled the presence of antiferromagnetism in an icosahedral quasicrystal (iQC), resolving a long-standing mystery in materials science. This discovery could have profound implications for the future of spintronics, magnetic refrigeration, and energy-efficient electronics, marking a new era in the study of quasiperiodic materials.
Quasicrystals (QCs) are unique materials that defy traditional atomic arrangement. Unlike regular crystals, where atoms repeat in a periodic fashion, QCs feature a long-range order that does not follow a regular pattern. Since their discovery, which earned a Nobel Prize in Chemistry, QCs have fascinated scientists for their unconventional symmetries and potential applications in advanced technologies, including spintronics and magnetic cooling.
Previously, ferromagnetism was discovered in gold-gallium-rare earth (Au-Ga-R) icosahedral QCs. However, antiferromagnetism, another key type of magnetic order, had not been observed in real QCs, leaving researchers to wonder if such a phenomenon was even possible within the quasiperiodic structure of these materials.
Groundbreaking Discovery of Antiferromagnetism
In a landmark study published in Nature Physics on April 14, 2025, a team led by Ryuji Tamura from the Tokyo University of Science (TUS) and supported by researchers from Tohoku University and the Australian Nuclear Science and Technology Organisation (ANSTO), has successfully observed antiferromagnetism in a real QC for the first time. This discovery challenges previous assumptions and opens new pathways for research into antiferromagnetic QCs.
Ryuji Tamura, the lead researcher, states, “As was the case for the first report of antiferromagnetism in a periodic crystal in 1949, we present the first experimental evidence of antiferromagnetism occurring in an iQC.”
Novel Materials Show Promise
Building upon their previous work with Au-Ga-R icosahedral QCs, the team identified a new type of gold-indium-europium (Au-In-Eu) iQC. This novel material displayed a combination of 5-fold, 3-fold, and 2-fold rotational symmetries. The researchers conducted a series of experiments to explore the magnetic properties of this material. Magnetic susceptibility measurements revealed a sharp cusp at a temperature of 6.5 Kelvin, indicating a transition into antiferromagnetic order.
Further validation came from neutron diffraction experiments. At temperatures of 10 K and 3 K, the team observed magnetic Bragg peaks—distinct peaks in the diffraction pattern that signify an ordered magnetic structure. These results provided the first clear evidence of long-range antiferromagnetic order in a real QC.
The Role of Curie-Weiss Temperature
One of the key findings in this study relates to the Curie-Weiss temperature, a critical parameter that influences the type of magnetic ordering in materials. Unlike most iQCs, which typically show a negative Curie-Weiss temperature, the Au-In-Eu iQC displayed a positive Curie-Weiss temperature. This positive value suggests a favourable environment for the establishment of antiferromagnetic order.
The team also discovered that by slightly altering the electron-per-atom ratio through elemental substitution, the antiferromagnetic phase could be disrupted, causing the material to revert to a spin-glass state, much like other studied iQCs. This insight offers new avenues for manipulating magnetic properties in QCs by adjusting the electron ratio.
Tamura comments, “This discovery finally resolves the longstanding issue of whether antiferromagnetic order is possible in real QCs. Antiferromagnetic QCs could enable unprecedented functions, such as ultrasoft magnetic responses, and will bring about a revolution in spintronics and magnetic refrigeration in the future.”
Implications for Technology and Sustainability
The discovery of antiferromagnetic QCs could have wide-reaching applications in fields such as spintronics and magnetic refrigeration, offering the potential for energy-efficient technologies. This aligns with the United Nations’ sustainable development goals (SDGs), particularly in promoting affordable and clean energy (SDG 7) and advancing industry, innovation, and infrastructure (SDG 9). By developing more efficient materials, these advancements could play a significant role in shaping the future of energy-efficient electronics.
About Tokyo University of Science (TUS)
Tokyo University of Science (TUS) is a leading private research institution in Japan, renowned for its contributions to scientific and technological advancement. Established in 1881, TUS continues to drive innovation through a multidisciplinary approach to research. The university is committed to fostering the next generation of scientists and researchers who contribute to global scientific progress. TUS has produced notable figures, including a Nobel Prize winner in the natural sciences.
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