单相室温多铁性材料的关键基础问题与新体系探索

In the present project, the systematical fundamental investigations are conducted on the modification of structures and properties of BiFeO3 multiferroic materials, exploring multiferroic new systems with tungsten bronze structure, and multiferroic characteristics and their modification of RFeO3 ceramics. Several fundamental key issues will be studied, and the new systems for room-temperature multiferroic materials will be explored from different points of view. The solid solution and MPB structure of RFeO3, SrTiO3 and/or CaTiO3-modified BiFeO3 materials are investigated together with the multiferroic mechanism, and the effective way for achieving the synergistic modification of BiFeO3 multiferroic materials will be determined. The multiferroic characteristics and their structural origin will be revealed for non-filled, filled and fully filled tungsten bronze ceramics, and the room-temperature multiferroic new material systems with tungsten bronze structure will be explored. Moreover, the multiferroic characteristics and their structural origin will be determined for RFeO3 ceramics, and the RFeO3-based multiferroic new material systems will be developed. The present project is expected to greatly contribute to the enrichment of ferroelectric and multiferroic physics, and subsequently the development in the field of multiferroic materials in China will be strongly promoted.

本项目拟从BiFeO3多铁性材料的结构性能调控、钨青铜多铁性材料新体系、以及RFeO3陶瓷的多铁性及其调控等三大方面展开系统的基础研究，以解决单相室温多铁性材料的若干基础问题，从不同视角探索室温多铁性材料新体系。揭示BiFeO3与RFeO3、SrTiO3及CaTiO3形成固溶体及多相界的规律，揭示改性BiFeO3-基材料的多铁性机制，找出实现BiFeO3多铁性材料协同改性的有效途径；揭示非充满型、充满型与全充满型钨青铜铁铌酸盐陶瓷的多铁性及其结构根源，探索出钨青铜室温多铁性材料新体系；揭示RFeO3陶瓷的多铁性及其结构根源，探索RFeO3基多铁性陶瓷新体系。本项目的实施，可望给铁电与多铁性理论带来突破，并有力促进我国多铁性材料领域的发展。

本项目从BiFeO3多铁性材料的结构性能调控、RFeO3陶瓷的多铁性及其调控、钨青铜多铁性材料新体系、以及基于理论计算的新材料体系探索等方面展开了系统的基础研究，取得如下主要成果：1)通过对称性调控、形成多相界，有效改善了BiFeO3的铁电性与磁性，并借助场致相变实现了BiFeO3陶瓷的电控磁性；2)揭示了稀土铁氧体RFeO3陶瓷中六角极性相的形成与演化规律，探索出Lu1-xInxFeO3室温多铁性材料新体系；3)制备出几种R-P结构氧化物陶瓷，并确认了其杂化非本征铁电性；4)探索了若干钨青铜多铁性材料新体系，探明仅有Ba4R2Fe2Nb8O30与Ba3SrR2Fe2Nb8O30 等少数充满型钨青铜化合物具有弛豫型多铁性材料的潜力；5)基于理论计算，预测了几种可能的近室温多铁性异质结。通过本项目的实施，发展了铁电与多铁性理论，促进了我国多铁性材料领域的发展。