BiFeO3基薄膜和异质结外电场下磁电响应及耦合研究

项目名称： BiFeO3基薄膜和异质结外电场下磁电响应及耦合研究

项目编号： No.11304248

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 冯宏剑

作者单位： 西北大学

项目金额： 25万元

中文摘要： 本研究基于密度泛函理论，发展出描述BiFeO3(BFO)基薄膜多物理场耦合效应的外部电场平板模型,对BFO基薄膜和异质结外部电场下的电子输运、轨道重构、自旋输运、晶格畸变和铁电响应的相互作用和耦合机理进行系统而具有开创性的研究。旨在探索外部电场作用下磁序、晶格畸变、铁电和微观电子输运诱导的磁电耦合机理，理论结合实验揭示外电场下自旋、轨道、电荷序、晶格和电子输运之间相互耦合的微观物理机制。室温BFO基薄膜外电场下磁电耦合机理的揭示对理解BFO基异质结交换偏置机理，设计外电场调控铁磁序的室温"电写磁读"高密度低能耗磁存储器件和自旋电子器件提供材料基础。本研究对于进一步认识磁电耦合机理的物理内涵，采用第一性原理进行量子调控设计新的性能优良的室温强磁电耦合多铁性材料提供重要的理论指导。

中文关键词： 多铁性材料；磁电耦合；BiFeO3 基薄膜；第一性原理；异质结

英文摘要： Based on density functional theory, we develop an improved slab model applying external electric field and aim to systematically investigate the magnetoelectric response and coupling effect involving electron transport, orbital reconstruction, spin tranfer,structural distortion, and ferroelectric response under external electric field in BiFeO3(BFO)-based films. Combined with the experimental methods,the slab model is used to reveal the mechanism of the magnetoelectric coupling effect mediated by spin,orbital,charge ordering,lattice, and electron transport under an external electric field in BFO-based films. This work is mainly focusing on the interaction and correlation among magnetic ordering, lattice distortion,ferroelectric charge ordering, and electron transport in magnetic ferroelectrics such as BFO-based films,and it will shed light on the understanding of the exchange-bias coupling involed in the BFO-based heterostructures and field-effect devices using the electric-field controllable magnetization. Hereby, it contributes a lot to the fabrication of high-density magnetic storage using electric-field tunable ferromagnetic magnetization reversal with lower energy consumption at room-temperature and has potential applications in the emerging field of spintronics.This work plays a crucial role in explor

英文关键词： Multiferroics；Magnetoelectric coupling；BiFeO3-based films；First-principles；Heterostructures