Improper flexoelectricity in hexagonal rare-earth ferrites
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arXiv
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| Autori principali: | , , , , , , , |
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| Natura: | Preprint |
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2024
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| _version_ | 1866908383122030592 |
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| author | Li, Xin Ren, Guodong Yun, Yu Thind, Arashdeep Singh Shah, Amit Kumar Bowers, Abbey Mishra, Rohan Xu, Xiaoshan |
| author_facet | Li, Xin Ren, Guodong Yun, Yu Thind, Arashdeep Singh Shah, Amit Kumar Bowers, Abbey Mishra, Rohan Xu, Xiaoshan |
| contents | Flexoelectricity is a universal effect that generates electric polarization due to broken inversion symmetry caused by local strain gradient. The large strain gradient at nanoscale makes flexo-electric effects, especially in nanoscopic ferroelectric materials, promising in sensors, actuator, energy harvesting, and memory applications. In this work, we studied flexoelectricity in hexagonal ferrites h-YbFeO3, an improper ferroelectric expected to have weak piezoelectricity and low sensitivity to depolarization field, which are advantageous for studying flexoelectric effects. We show that in h-YbFeO3 epitaxial thin films, strain gradient on the order of 10^6 m-1 occurs near grain boundaries and edge dislocation, which has a significant impact on the non-polar K3 structural distortion that induces spontaneous polarization. The phenomenological model based on the Landau theory of improper ferroelectricity suggests an indirect flexoelectric effect on the order of 10 nC/m in h-YbFeO3, which is substantially larger than the expectation from Kogan mechanism. These results reveal a novel microscopic mechanism of coupling between strain gradient and polarization mediated by structural distortion, which we call improper flexoelectricity. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2409_17022 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Improper flexoelectricity in hexagonal rare-earth ferrites Li, Xin Ren, Guodong Yun, Yu Thind, Arashdeep Singh Shah, Amit Kumar Bowers, Abbey Mishra, Rohan Xu, Xiaoshan Materials Science Flexoelectricity is a universal effect that generates electric polarization due to broken inversion symmetry caused by local strain gradient. The large strain gradient at nanoscale makes flexo-electric effects, especially in nanoscopic ferroelectric materials, promising in sensors, actuator, energy harvesting, and memory applications. In this work, we studied flexoelectricity in hexagonal ferrites h-YbFeO3, an improper ferroelectric expected to have weak piezoelectricity and low sensitivity to depolarization field, which are advantageous for studying flexoelectric effects. We show that in h-YbFeO3 epitaxial thin films, strain gradient on the order of 10^6 m-1 occurs near grain boundaries and edge dislocation, which has a significant impact on the non-polar K3 structural distortion that induces spontaneous polarization. The phenomenological model based on the Landau theory of improper ferroelectricity suggests an indirect flexoelectric effect on the order of 10 nC/m in h-YbFeO3, which is substantially larger than the expectation from Kogan mechanism. These results reveal a novel microscopic mechanism of coupling between strain gradient and polarization mediated by structural distortion, which we call improper flexoelectricity. |
| title | Improper flexoelectricity in hexagonal rare-earth ferrites |
| topic | Materials Science |
| url | https://arxiv.org/abs/2409.17022 |