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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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.
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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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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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DOI: https://doi.org/10.1038/nmat4857
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