Spin current generation from an epitaxial tungsten dioxide WO2
We report on efficient spin current generation at room temperature in rutile-type WO2 grown on an Al2O3(0001) substrate. The optimal WO2 film has a (010)-oriented monoclinically distorted rutile structure with metallic conductivity due to 5d2 electrons, as characterized by x-ray diffraction, electro...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2023-06-01
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| Series: | APL Materials |
| Online Access: | http://dx.doi.org/10.1063/5.0153533 |
| _version_ | 1797771806612914176 |
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| author | Kohei Ueda Hayato Fujii Takanori Kida Masayuki Hagiwara Jobu Matsuno |
| author_facet | Kohei Ueda Hayato Fujii Takanori Kida Masayuki Hagiwara Jobu Matsuno |
| author_sort | Kohei Ueda |
| collection | DOAJ |
| description | We report on efficient spin current generation at room temperature in rutile-type WO2 grown on an Al2O3(0001) substrate. The optimal WO2 film has a (010)-oriented monoclinically distorted rutile structure with metallic conductivity due to 5d2 electrons, as characterized by x-ray diffraction, electronic transport, and x-ray photoelectron spectroscopy. By conducting harmonic Hall measurement in a Ni81Fe19/WO2 bilayer, we estimate two symmetries of the spin–orbit torque (SOT), i.e., dampinglike (DL) and fieldlike ones, to find that the former is larger than the latter. By comparison with the Ni81Fe19/W control sample, the observed DL SOT efficiency ξDL of WO2 (+0.174) is about two-thirds of that of W (−0.281) in magnitude, with a striking difference in their signs. The magnitude of the ξDL of WO2 exhibits a comparable value to those of widely reported Pt and Ta, and Ir oxide IrO2. The positive sign of the ξDL of WO2 can be explained by the preceding theoretical study based on the 4d oxides. These results highlight that the epitaxial WO2 offers a great opportunity of rutile oxides with spintronic functionalities, leading to future spin–orbit torque-controlled devices. |
| first_indexed | 2024-03-12T21:42:53Z |
| format | Article |
| id | doaj.art-f46c6dcc95b349c3a1aad9f985f1f093 |
| institution | Directory Open Access Journal |
| issn | 2166-532X |
| language | English |
| last_indexed | 2024-03-12T21:42:53Z |
| publishDate | 2023-06-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | APL Materials |
| spelling | doaj.art-f46c6dcc95b349c3a1aad9f985f1f0932023-07-26T16:22:28ZengAIP Publishing LLCAPL Materials2166-532X2023-06-01116061125061125-710.1063/5.0153533Spin current generation from an epitaxial tungsten dioxide WO2Kohei Ueda0Hayato Fujii1Takanori Kida2Masayuki Hagiwara3Jobu Matsuno4Department of Physics, Graduate School of Science, Osaka University, Osaka 560-0043, JapanDepartment of Physics, Graduate School of Science, Osaka University, Osaka 560-0043, JapanCenter for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, Osaka 560-0043, JapanCenter for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, Osaka 560-0043, JapanDepartment of Physics, Graduate School of Science, Osaka University, Osaka 560-0043, JapanWe report on efficient spin current generation at room temperature in rutile-type WO2 grown on an Al2O3(0001) substrate. The optimal WO2 film has a (010)-oriented monoclinically distorted rutile structure with metallic conductivity due to 5d2 electrons, as characterized by x-ray diffraction, electronic transport, and x-ray photoelectron spectroscopy. By conducting harmonic Hall measurement in a Ni81Fe19/WO2 bilayer, we estimate two symmetries of the spin–orbit torque (SOT), i.e., dampinglike (DL) and fieldlike ones, to find that the former is larger than the latter. By comparison with the Ni81Fe19/W control sample, the observed DL SOT efficiency ξDL of WO2 (+0.174) is about two-thirds of that of W (−0.281) in magnitude, with a striking difference in their signs. The magnitude of the ξDL of WO2 exhibits a comparable value to those of widely reported Pt and Ta, and Ir oxide IrO2. The positive sign of the ξDL of WO2 can be explained by the preceding theoretical study based on the 4d oxides. These results highlight that the epitaxial WO2 offers a great opportunity of rutile oxides with spintronic functionalities, leading to future spin–orbit torque-controlled devices.http://dx.doi.org/10.1063/5.0153533 |
| spellingShingle | Kohei Ueda Hayato Fujii Takanori Kida Masayuki Hagiwara Jobu Matsuno Spin current generation from an epitaxial tungsten dioxide WO2 APL Materials |
| title | Spin current generation from an epitaxial tungsten dioxide WO2 |
| title_full | Spin current generation from an epitaxial tungsten dioxide WO2 |
| title_fullStr | Spin current generation from an epitaxial tungsten dioxide WO2 |
| title_full_unstemmed | Spin current generation from an epitaxial tungsten dioxide WO2 |
| title_short | Spin current generation from an epitaxial tungsten dioxide WO2 |
| title_sort | spin current generation from an epitaxial tungsten dioxide wo2 |
| url | http://dx.doi.org/10.1063/5.0153533 |
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