离子无序诱导多铁性物理效应与铁性序耦合机制研究

The multiferroics as novel class of condensed matter physics have been receiving special attentions due to the underlying physics associated with the ferroic order couplings and inter-manipulations. Among them, the iron-based ferroelectric materials show superior properties and rich physics, and thus can be a promising breakout for searching high-performance new multiferroics. Motivated by earlier works including our own contributions on the type II multiferroics, the present proposal is intended to focus on the iron-based transition metal polar magnets, and explore the emerging new physical phenomenon and mechanism that stimulated by the ion disorder effect. The physical origin and correlation between different microscopic mechanisms will be clarified, including: (1) exploring high-performance new iron-based polar multiferroics; (2) novel magnetoelectric response and microscopic mechanism triggered by ion disorder; (3) This propoals try to understand the emergent features activated by ion disorder in these multiferroic materials hosting multiple magnetic sublattices, and realize new ferroic order coupling mechanism. Eventually, much effort will be contributed to providing physical foundation for designing and synthetizing high-performance and potential application of multiferroics.

多铁性因其蕴含深刻的铁性序耦合与调控物理而成为凝聚态物理关注的热点之一。铁基铁电氧化物具有优良的多铁性能，物理内涵丰富，是寻找新的高性能多铁性材料的出路。本申请以申请人近几年在磁致多铁性材料物理方面的研究工作为基础，以具有极性空间群的铁基过渡金属磁性化合物为立足点，引入离子无序效应，着重开展离子无序协同多铁性的新物理效应和新机制，阐明其中的物理根源，理解不同微观机制之间的关联，包括：(1)高性能极性铁基多铁性新材料探索；(2)离子无序调控多铁性新效应和微观机制；(3)揭示离子无序协同多磁矩的组合与调控物理，实现新的自旋序与铁电序耦合机制，为设计合成具有优异性能与应用潜力的多铁性材料提供物理基础。

在项目执行的四年中，项目负责人和团队紧密围绕多铁性新材料、新物理效应与铁性序耦合物理机制开展研究工作。除了铁基极性磁体外，我们对材料体系有所扩大和调整，取得了一系列的研究成果，较好实现了既定的科学目标。具体研究成果包括：(1)设计制备了3种极性铁基多铁性新材料体系，深入研究磁电耦合物理效应。(2)揭示了离子无序调控多铁性效应，初步实现电控磁性。(3)合成4种具有强线性磁电耦合效应新材料，实现了磁场诱导多铁相变，揭示不同微观机制间的关联。