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Strong evidence for d-electron spin transport at room temperature at a LaAlO3/SrTiO3 interface

Nature Materials volume 16, pages 609–614 (2017)Cite this article

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Abstract

A d-orbital electron has an anisotropic electron orbital and is a source of magnetism. The realization of a two-dimensional electron gas (2DEG) embedded at a LaAlO3/SrTiO3 interface surprised researchers in materials and physical sciences because the 2DEG consists of 3d-electrons of Ti with extraordinarily large carrier mobility, even in the insulating oxide heterostructure. To date, a wide variety of physical phenomena, such as ferromagnetism and the quantum Hall effect, have been discovered in this 2DEG system, demonstrating the ability of d-electron 2DEG systems to provide a material platform for the study of interesting physics. However, because of both ferromagnetism and the Rashba field, long-range spin transport and the exploitation of spintronics functions have been believed difficult to implement in d-electron 2DEG systems. Here, we report the experimental demonstration of room-temperature spin transport in a d-electron-based 2DEG at a LaAlO3/SrTiO3 interface, where the spin relaxation length is about 300 nm. Our finding, which counters the conventional understandings of d-electron 2DEGs, highlights the spin-functionality of conductive oxide systems and opens the field of d-electron spintronics.

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Figure 1: Experimental set-up and current–voltage (I–V) characteristics of the Py-LAO/STO-detection electrodes.
Figure 2: Angular dependences of the electromotive force of the inverse spin Hall effect.
Figure 3: Electromotive forces obtained from the Ta electrode sample.
Figure 4: Magnitudes of the ISHE-induced electric current as a function of the gap length between the Py and the Pt or Ta.
Figure 5: The Gilbert damping α of full-capping Py on the 2DEG at LAO/STO interfaces under spin-pumping conditions.

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Acknowledgements

This research was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, Innovative Area ‘Nano Spin Conversion Science’ (No. 26103003), Scientific Research (S) ‘Semiconductor Spincurrentronics’ (No. 16H0633), JSPS KAKENHI Grant (No. 16J00485), JSPS KAKENHI Grant (No. 25286506) and Elements Strategy Initiative to Form Core Research Center. One of the authors (R.O.) acknowledges JSPS Research Fellow.

Author information

Authors and Affiliations

  1. Department of Electronic Science and Engineering, Kyoto University, 615-8510 Kyoto, Japan

    Ryo Ohshima, Yuichiro Ando, Teruya Shinjo & Masashi Shiraishi

  2. Graduate School of Engineering Science, Osaka University, 560-8531 Toyonaka, Japan

    Ryo Ohshima

  3. Secure Materials Center, Materials and Structures Laboratories, Tokyo Institute of Technology, 226-8503 Yokohama, Japan

    Kosuke Matsuzaki & Tomofumi Susaki

  4. Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany

    Mathias Weiler, Stefan Klingler, Hans Huebl & Sebastian T. B. Goennenwein

  5. Physik-Department, Technische Universität München, 85748 Garching, Germany

    Mathias Weiler, Stefan Klingler, Hans Huebl & Sebastian T. B. Goennenwein

  6. Nanosystems Initiative Munich, 80799 München, Germany

    Hans Huebl & Sebastian T. B. Goennenwein

  7. Graduate School of Engineering, Osaka City University, 558-8585 Osaka, Japan

    Eiji Shikoh

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Contributions

M.S., Y.A., R.O., S.T.B.G., H.H. and M.W. conceived and designed the experiments. T.Shinjo supervised the project. R.O., T.Susaki and K.M. fabricated the samples with the help of E.S. R.O. and S.K. performed the experiments. R.O., M.S., Y.A., T.Shinjo, S.K., M.W., H.H. and S.T.B.G. analyzed the data. R.O., M.S., Y.A., K.M., T.Susaki, M.W., H.H. and S.T.B.G. wrote the manuscript. All authors discussed the data and contributed to the manuscript.

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Correspondence to Masashi Shiraishi.

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Ohshima, R., Ando, Y., Matsuzaki, K. et al. Strong evidence for d-electron spin transport at room temperature at a LaAlO3/SrTiO3 interface. Nature Mater 16, 609–614 (2017). https://doi.org/10.1038/nmat4857

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