Microstructural Underpinnings of Giant Intrinsic Exchange Bias in Epitaxial NiCo2O4 Thin Films
Abstract Understanding intrinsic exchange bias in nominally single‐component ferromagnetic or ferrimagnetic materials is crucial for simplifying related device architectures. However, the mechanisms behind this phenomenon and its tunability remain elusive, which hinders the efforts to achieve unidir...
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| Format: | Article |
| Language: | English |
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Wiley-VCH
2025-02-01
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| Series: | Advanced Electronic Materials |
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| Online Access: | https://doi.org/10.1002/aelm.202400149 |
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| author | Detian Yang Arjun Subedi Chao Liu Haile Ambaye Valeria Lauter Peter A. Dowben Yaohua Liu Xiaoshan Xu |
| author_facet | Detian Yang Arjun Subedi Chao Liu Haile Ambaye Valeria Lauter Peter A. Dowben Yaohua Liu Xiaoshan Xu |
| author_sort | Detian Yang |
| collection | DOAJ |
| description | Abstract Understanding intrinsic exchange bias in nominally single‐component ferromagnetic or ferrimagnetic materials is crucial for simplifying related device architectures. However, the mechanisms behind this phenomenon and its tunability remain elusive, which hinders the efforts to achieve unidirectional magnetization for widespread applications. Inspired by the high tunability of ferrimagnetic inverse spinel NiCo2O4, the origin of intrinsic exchange bias in NiCo2O4 (111) films deposited on Al2O3 (0001) substrates are investigated. The comprehensive characterizations, including electron diffraction, X‐ray reflectometry and spectroscopy, and polarized neutron reflectometry, reveal that intrinsic exchange bias in NiCo2O4 (111)/Al2O3 (0001) arises from a reconstructed antiferromagnetic rock‐salt NixCo1‐xO layer at the interface between the film and the substrate due to a significant structural mismatch. Remarkably, by engineering the interfacial structure under optimal growth conditions, it can achieve exchange bias larger than coercivity, leading to unidirectional magnetization. Such giant intrinsic exchange bias can be utilized for realistic device applications. This work establishes a new material platform based on NiCo2O4, an emergent spintronics material, to study tunable interfacial magnetic and spintronic properties. |
| format | Article |
| id | doaj-art-e4917c560e914921bab886298f69d3eb |
| institution | OA Journals |
| issn | 2199-160X |
| language | English |
| publishDate | 2025-02-01 |
| publisher | Wiley-VCH |
| record_format | Article |
| series | Advanced Electronic Materials |
| spelling | doaj-art-e4917c560e914921bab886298f69d3eb2025-08-20T02:29:38ZengWiley-VCHAdvanced Electronic Materials2199-160X2025-02-01112n/an/a10.1002/aelm.202400149Microstructural Underpinnings of Giant Intrinsic Exchange Bias in Epitaxial NiCo2O4 Thin FilmsDetian Yang0Arjun Subedi1Chao Liu2Haile Ambaye3Valeria Lauter4Peter A. Dowben5Yaohua Liu6Xiaoshan Xu7Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience University of Nebraska‐Lincoln 855 N16th St Lincoln NE 68588 USADepartment of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience University of Nebraska‐Lincoln 855 N16th St Lincoln NE 68588 USADepartment of Materials Science and Engineering National University of Singapore Singapore 117575 SingaporeNeutron Scattering Division Oak Ridge National Laboratory Oak Ridge TN 37830 USANeutron Scattering Division Oak Ridge National Laboratory Oak Ridge TN 37830 USADepartment of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience University of Nebraska‐Lincoln 855 N16th St Lincoln NE 68588 USASecond Target Station Oak Ridge National Laboratory Oak Ridge TN 37830 USADepartment of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience University of Nebraska‐Lincoln 855 N16th St Lincoln NE 68588 USAAbstract Understanding intrinsic exchange bias in nominally single‐component ferromagnetic or ferrimagnetic materials is crucial for simplifying related device architectures. However, the mechanisms behind this phenomenon and its tunability remain elusive, which hinders the efforts to achieve unidirectional magnetization for widespread applications. Inspired by the high tunability of ferrimagnetic inverse spinel NiCo2O4, the origin of intrinsic exchange bias in NiCo2O4 (111) films deposited on Al2O3 (0001) substrates are investigated. The comprehensive characterizations, including electron diffraction, X‐ray reflectometry and spectroscopy, and polarized neutron reflectometry, reveal that intrinsic exchange bias in NiCo2O4 (111)/Al2O3 (0001) arises from a reconstructed antiferromagnetic rock‐salt NixCo1‐xO layer at the interface between the film and the substrate due to a significant structural mismatch. Remarkably, by engineering the interfacial structure under optimal growth conditions, it can achieve exchange bias larger than coercivity, leading to unidirectional magnetization. Such giant intrinsic exchange bias can be utilized for realistic device applications. This work establishes a new material platform based on NiCo2O4, an emergent spintronics material, to study tunable interfacial magnetic and spintronic properties.https://doi.org/10.1002/aelm.202400149intrinsic exchange biasnickel cobaltateoxide thin filmspolarization neutron reflectionX‐ray photoemission spectroscopy |
| spellingShingle | Detian Yang Arjun Subedi Chao Liu Haile Ambaye Valeria Lauter Peter A. Dowben Yaohua Liu Xiaoshan Xu Microstructural Underpinnings of Giant Intrinsic Exchange Bias in Epitaxial NiCo2O4 Thin Films Advanced Electronic Materials intrinsic exchange bias nickel cobaltate oxide thin films polarization neutron reflection X‐ray photoemission spectroscopy |
| title | Microstructural Underpinnings of Giant Intrinsic Exchange Bias in Epitaxial NiCo2O4 Thin Films |
| title_full | Microstructural Underpinnings of Giant Intrinsic Exchange Bias in Epitaxial NiCo2O4 Thin Films |
| title_fullStr | Microstructural Underpinnings of Giant Intrinsic Exchange Bias in Epitaxial NiCo2O4 Thin Films |
| title_full_unstemmed | Microstructural Underpinnings of Giant Intrinsic Exchange Bias in Epitaxial NiCo2O4 Thin Films |
| title_short | Microstructural Underpinnings of Giant Intrinsic Exchange Bias in Epitaxial NiCo2O4 Thin Films |
| title_sort | microstructural underpinnings of giant intrinsic exchange bias in epitaxial nico2o4 thin films |
| topic | intrinsic exchange bias nickel cobaltate oxide thin films polarization neutron reflection X‐ray photoemission spectroscopy |
| url | https://doi.org/10.1002/aelm.202400149 |
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