Deterministic, Reversible, and Nonvolatile Low-Voltage Writing of Magnetic Domains in Epitaxial BaTiO3/Fe3O4 Heterostructure
Time：18 Dec. 2018Source：School of Aeronautics and Astronautics-Zhejiang UniversityAuthor：安婉Click：7
| Date | 18th Dec. 2018 |
| Time | 10:20-11:30 |
| Venue | Room 118, Building 12, Yuquan Campus |
| Speaker | Prof. Li Jiangyu (University of Washington) |
| Abstract | The ability to electrically write magnetic bits is highly desirable for future magnetic memories and spintronic devices, though fully deterministic, reversible, and nonvolatile switching of magnetic moments by electric field remains elusive despite extensive research. In this work, we develop a concept to electrically switch magnetization via polarization modulated oxygen vacancies, and we demonstrate the idea in a multiferroic epitaxial heterostructure of BaTiO3/Fe3O4 fabricated by pulsed laser deposition. The piezoelectricity and ferroelectricity of BaTiO3 have been confirmed by macro- and microscale measurements, for which Fe3O4 serves as the top electrode for switching the polarization. X-ray absorption spectroscopy and X-ray magnetic circular dichroism spectra indicate a mixture of Fe2+ and Fe3+ at Oh sites and Fe3+ at Td sites in Fe3O4, while the room-temperature magnetic domains of Fe3O4 are revealed by microscopic magnetic force microscopy measurements. It is demonstrated that the magnetic domains of Fe3O4 can be switched by not only magnetic fields but also electric fields in a deterministic, reversible, and nonvolatile manner, wherein polarization reversal by electric field modulates the oxygen vacancy distribution in Fe3O4, and thus its magnetic state, making it attractive for electrically written magnetic memories. |
| Speaker | Jiangyu Li is a Professor in the Department of Mechanical Engineering, University of Washington. He obtained his B.E. degree in 1994 from the Department of Materials Science and Engineering, Tsinghua University, and Ph.D. degree in 1998 from the Department of Mechanical Engineering, University of Colorado-Boulder. Li works in the general field of mechanics of materials, focusing on advanced scanning probe microscopy and its applications in functional materials. He has published over 200 journal articles, and has been recognized by Sia Nemat-Nasser Medal from ASEM, Young Investigator Award from ICCES, and Microscopy Today Innovation Award from Microscopy Society of America. He currently serves as Associate Editor for Journal of Applied Physics and Science Bulletin. |
