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Abstract:
Magnetoelectric effects in materials provide a great opportunity to use an electric field to control ferromagnetism. Magnetoelectric coupling between electric and magnetic order parameters has been theoretically predicted, and there is intense interest in its implementation in device architectures taking advantage of these properties. Single-phase multiferroics – materials that show spontaneous magnetization and polarization simultaneously at ambient conditions – remain elusive as most systems (such as the manganites) exhibit mulitferroicity only at low temperatures. Alternatively, multiferroics can be synthesized as a composite system, e.g. as a product property of a composite phase consisting of a magnetostrictive and a piezoelectric material. Hence, the search continues for new single-phase and composite multiferroic materials that exhibit high ordering temperatures. One multiferroic material, however, has played a key role in rejuvenating the field after a report of large ferroelectric polarization combined with interesting magnetic properties – BiFeO3 (BFO). The large ferroelectric polarization in BFO epitaxial films is in sharp contrast to the weak polarization observed earlier in the bulk, but in good agreement with theoretical results. Central to the interest in BFO is that it is a room-temperature multiferroic material with both a high ferroelectric Curie temperature and a high antiferromagnetic Néel temperature. The coupling between order parameters in BFO, as the case for some multiferroic manganites at low temperature, offers exciting potential for room temperature device integration. Recent studies suggest several interesting phenomena in this material, which can be controlled by electric field., have been show. All these provide the possibility for new functionality. In this talk, there will be a quick review on BFO thin films and then some new findings and future directions will be discussed.
The issues will be addressed in this talk:
1. Electrically Controllable Exchange Coupling with Multiferroic BiFeO3 Thin Films
2. Electrically Controllable Multifunctional Domain Walls in BiFeO3 Thin Films
3. Electrically Controllable Conduction in Doped BiFeO3 Thin Films
4. Electrically Controllable Iso-symmetric Phase Transition in BiFeO3 Thin Films
联系人：于荣 老师 62773998 |
