Top > Research results > The University of Tokyo and others create a new spiral magnetic material whose spin array is twisted when expanded.

2018/11/4

The University of Tokyo and others create a new spiral magnetic material whose spin array is twisted when expanded.

University Journal Online Editorial Department

　The "spiral magnetic material" in which the spins are arranged in a spiral shape is expected to be a new spintronics material that utilizes the twisting method of the spins as information.However, substances exhibiting spiral magnetism are rare, and even perovskite-type transition metal oxides, which have been studied for a long time as spintronics materials, have been reported in a limited number of cases.

　This time, the research group of the University of Tokyo and Osaka University focused on cobalt oxide with a cubic perovskite-type structure.It is known that when iron oxide with the same structure and spiral magnetism stretches the bond length of iron and oxygen, the twisting of the spin arrangement changes significantly, so the bond length of cobalt and oxygen is also stretched in the same way. We aimed to search for a novel magnetic phase.

　By ultra-high pressure oxidation treatment, a large single crystal of perovskite type cobalt oxide whose bond length is extended by element substitution is synthesized while maintaining a strong bond between cobalt and oxygen, which is considered to be necessary for spiral magnetism.Magnetization measurements were performed on the obtained single crystal, and it was found that the ferromagnetic phase was changed to a new magnetic phase by increasing the bond length between cobalt and oxygen by only about 1%.Furthermore, it was confirmed from experiments and theoretical calculations that this new magnetic phase is a spiral magnetic phase.

　This proved for the first time in the world that even an oxide having a simple crystal structure such as cubic perovskite can generate spiral magnetism by controlling the strong bond between the transition metal and oxygen.

　This result provides a new guideline that will lead to the development of new oxide spiral magnetic materials, and at the same time, the magnetic switching of ferromagnetic-spiral magnetic transition due to the increase of crystal lattice will be applied to new pressure sensors and magnetic actuators. It is expected to lead to applications.

Paper information:[Physical Review Materials] Negative-pressure-induced helimagnetism in recently cubic perovskites Sr1-xBaxCoO3

Tokyo University

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The University of Tokyo was established in 1877 (Meiji 10) by integrating the Tokyo Kaisei School and the Tokyo Medical School.Since its establishment, it has developed education and research in a unique way in the world as a leading university in Japan and an academic center for the fusion of East and West cultures.As a result, many human resources have been produced in a wide range of fields, and many research achievements […]

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Osaka University

The "true value" of each person becomes the "evolution" of Osaka University.To a university that lives in the community and extends to the world

Osaka University is a research-based university with 11 faculties and 23 departments. Since its founding in 1931, with the motto of "living in the region and extending to the world," we have created an outstanding "foundation" and "power" that weaves advanced education and research capabilities, the harmony of faculty and staff, and the weight of tradition and the advantage of Osaka. I have.Taking advantage of these excellent potentials […]

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Tohoku University

Create excellent research results that will be the source of innovation, and develop talented human resources who will lead the next generation

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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