Top > Research results > Joint research > Two-dimensional ferromagnetic fluctuation observation for the first time in cuprate superconductors Sophia University and others

2018/8/12

Two-dimensional ferromagnetic fluctuation observation for the first time in cuprate superconductors Sophia University and others

University Journal Online Editorial Department

　Superconductivity (a phenomenon in which the electrical resistance of a substance suddenly becomes zero below a certain temperature) discovered in 1911 is deeply involved in our lives with the linear Shinkansen and magnetic resonance imaging (MRI).In particular, high-temperature superconductivity found in copper oxides is being actively studied to elucidate the mechanism of high critical temperature.

　In copper oxide, when holes or electron carriers responsible for electrical conduction are injected into an antiferromagnetic insulator material, the antiferromagnetic order is broken and superconductivity is developed.Since antiferromagnetic fluctuations have been observed in substances that exhibit superconductivity, it is said that antiferromagnetic fluctuations are deeply involved in the mechanism of superconductivity.
On the other hand, when a large amount of carriers are injected, superconductivity disappears, but the cause is unknown, and it is unclear what the magnetic state is with the substance injected with a large amount of carriers.

　This time, a research group led by Sophia University and Tohoku University observed two-dimensional ferromagnetic fluctuations for the first time in the world with a copper oxide injected with a large amount of holes.This means that the magnetic state changes from antiferromagnetism to ferromagnetism with the injection of carriers.In addition, since ferromagnetic fluctuations were observed in substances in which superconductivity was greatly suppressed, it is possible that ferromagnetic fluctuations are inhibiting high-temperature superconductivity, which has been a mystery for a long time. It can be said that the cause of the disappearance of superconductivity when injected can be clarified.

　From this result, it became clear that a two-dimensional ferromagnetic fluctuation state appears when a large amount of holes are injected in a copper oxide whose existence of antiferromagnetic state and superconducting state has been known so far. It was suggested that ferromagnetic fluctuations may be involved in superconductivity.It is expected to show a new way for research on high-temperature superconductivity in the future.

Paper information:[Physical Review Letters] Development of Ferromagnetic Fluctuations in Heavily Overdoped (Bi, Pb) 2Sr2CuO6 + δ Copper Oxides

Tohoku University

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Tohoku University has a rich culture and humanity based on the tradition of "research first principle" since its opening, the idea of ​​"opening the door" and the spirit of "respect for practical science", and is a phenomenon of human beings, society and nature. In response to this, human resources with the ability to carry out intellectual exploration with a "scientific mind", demonstrating their expertise in various fields from an international perspective and leading […]

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Sophia University

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Sophia University provides a learning environment where international students and professors from all over the world gather, advanced foreign language education, and traditional human education.As a university that drives globalization, the enhancement of the "Global Campus" is unparalleled. By concentrating all nine faculties on one campus, academic diversity is ensured and complex […]

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Muroran Institute of Technology

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A national university headquartered in Muroran, the largest industrial city in Hokkaido. We are developing a wide range of science and engineering human resources with the philosophy of "making dreams come true with creative science and technology."By acquiring a wide range of basics of engineering and science and information processing ability, you can use creativity that computers cannot do, master AI and big data, and the world […]

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University Journal Online Editorial Department

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