强磁场下Bi6Fe2Ti3O18基多铁性薄膜的制备及磁电性能调控研究

Layer-structured Bi-based Aurivillius phase compounds exhibit both the coexistence of ferromagnetism and ferroelectricity at room temperature and the obvious magnetoelectric (ME) coupling effect at low temperature, and thus such materials have aroused the extensive interest in the field of single-phase multiferroics. In present, how to optimize the room-temperature multiferroic properties and improve the work temperature region of magnetoelectric coupling effect will determine the prospects for application. In this project, the Bi6Fe2Ti3O18-based thin films will be prepared by chemical solution deposition, and then the proper elements will be selected for doping to improve the multiferroic properties and ME effect. Meanwhile, taking into account the special role of high magnetic field in the nucleation and growth of thin films, magnetic field will be introduced in the preparation process of Bi6Fe2Ti3O18 thin films, and the effects of direction and intensity of magnetic field on the grain size, orientation, and texture degree of thin films will be investigated. Based on the above work, we will carry out the thickness effect study for high quality films under high magnetic field in order to further optimize multiferroic properties and ME effect, and establish the relationship between magnetic field and multiferroic ordering parameters, and thus provide the experimental and theoretical basis for the preparation of multiferroic materials under high magnetic field in the future.

层状Bi基Aurivillius相化合物在室温条件下表现出铁电和铁磁共存以及低温条件下具有显著的磁电耦合效应，因此该类材料在单相多铁材料领域引发了广泛的兴趣。目前，如何优化该材料体系的室温多铁性以及提高磁电耦合效应的工作温区直接决定了其应用前景。本项目拟采用化学溶液沉积法制备Bi6Fe2Ti3O18基薄膜，通过合适的元素掺杂改善材料的多铁性和磁电耦合效应。同时考虑到强磁场在薄膜形核和长大过程中的特殊作用，在Bi6Fe2Ti3O18薄膜的制备过程中引入强磁场，研究强磁场的方向和大小对薄膜的晶粒尺寸、取向和致密度的作用规律。结合前期的工作，我们对性能优异的薄膜开展强磁场条件下的不同厚度效应研究，以进一步优化材料的多铁性和磁电耦合效应，建立强磁场与多铁序参量之间的关联，为后期探索强磁场制备多铁材料提供实验和理论依据。