层状Aurivillius相Bi2An-1BnO3n+3(n=5)室温单相多铁性材料的制备及多场耦合效应的调控研究

The magnetoelectric (ME) effect of room-temperature single-phase multiferroic material BiFeO3 is weak due to its antiferromagnetic nature, which is a large obstacle for the application prospect. Wheareas, the ferromagnetic materials with ferroelectricity may exhibit a rather large magnenoelectric coupling. Therefore, the proposal will focus on the exploaration of room-temperature single-phase ferromagnetic materials with ferroelectricity based on the compounds Bi6Ti3Fe2O18 with the layered structure of Aurivillius phase through an appropriate doping elements and method.Based on the systematic investigations on the structural, magnetic, dielectric, ferroelectric, and ME properites of the materials, we proposed to prepare the compounds in high magnetic field in order to enhance their ME effects, aming at setting up the correlation between magnetic field, microstructure, and order parameters of multiferroic materials and shedding light on the tunability rule and mechanism of the magnitude and direction of high magnetic field on the order parameters of multiferroic materials for the purpose of realization of giant ME effect and set-up of the microscopic mechanisms.The proposal aims to explore the room-temperature single-phase multiferroics with a strong ME effect, and thus provide the experimental and theoretical basis for the development of next-generation memory devices.

目前室温单相多铁性材料BiFeO3由于其反铁磁的本质致使它的磁电效应很微弱，这对于其应用前景是一个巨大的瓶颈，而具有铁电性的铁磁材料有可能表现出较大的磁电耦合系数。本项目拟采用Pechini方法和化学溶液沉积方法分别制备块材和薄膜的n=5的层状Aurivillius结构相Bi6Ti3Fe2O18样品，通过选择合理的掺杂方法和掺杂元素，探索室温单相的多铁性材料。在对该类材料体系的结构、磁性质、介电、铁电性质及磁电效应进行系统研究的基础上，通过强磁场改变类钙钛矿结构单元内/之间的耦合来增强体系的磁性能和磁电效应，建立体系在外加强磁场下微结构的变化和多铁体序参量变化之间的关联，揭示外加磁场大小、方向和烧结/退火温度对多铁体序参量的调控规建和作用机理，实现巨磁电耦合响应并建立微观物理机制。通过本项目研究以期得到室温单相且具有强磁电效应的多铁体，从而为开发下一代信息存储功能器件奠定实验和理论基础。

目前室温单相多铁性材料BiFeO3由于其反铁磁的本质致使它的磁电效应很微弱，这对于其应用前景是一个巨大的瓶颈，而具有铁电性的铁磁材料有可能表现出较大的磁电耦合系数。前期工作表明具有层状层状Aurivillius结构的化合物可能是一种潜在的室温多铁性材料。本项目分别制备块材和薄膜的n=5的层状Aurivillius结构相Bi6Ti3Fe2O18样品，通过选择合理的掺杂方法和掺杂元素，探索室温单相的多铁性材料。在此基础上，筛选出具有室温多铁性的体系，通过强磁场下制备，进一步增强了体系的磁性和铁电性能，建立体系在外加强磁场下微结构的变化和多铁体序参量变化之间的关联，揭示外加磁场大小、方向和烧结/退火温度对多铁体序参量的调控规建和作用机理。

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