畸变双钙钛矿结构化合物的合成与磁电耦合性质

Synthesize optimal compounds from nano structure, film structure to a single crystal structure by high pressure hydrothermal method, sparking plasma sintering method and induced magnetron sputtering method. Introduce the intrinsic and non-intrinsic defects using unequal valent replacement, spin injection, ion implantation, and magnetic granular film method. Study on electron spin asymmetry change rule by structural distortion caused in external electric field. Assemble and coupling nano- micro-scale crystal gains so as to control the ferromagnetic/antiferromagnetic exchange interaction of layered spin state. Reveal the relationship between electronic spin status and defects on orbits.Study their special functional properties. Clarify the physical essence of magnetoelectric coupling effect in distortion double-perovskite compounds. Through the first principle method, the theory calculation and simulation was performed on crystal structure, magnetic, electrical properties for the distortion perovskite-like compounds. Establish the quantitative relationship between of the chemical bond and structure, component and physical properties of the compounds. Explain theoretically the fancy magnetoelectric properties for distorted perovskite structure compounds strange so as to predict and conformational synthesis of novel magnetoelectric material. Try to successfully make up the magnetoelectric coupling device with high mobility, high dielectric, and negative thermal expansion properties.

采用高压水热法、放电等离子烧结法、诱导磁控溅射法合成从纳米结构、薄膜结构到单晶体结构的化合物，利用不等价取代、自旋注入、离子注入、磁性颗粒膜等方法引入本征缺陷和非本征缺陷；研究外场作用下的结构畸变引起价态及电子自旋不对称性变化的规律，将纳微米晶粒进行组装与耦合，调控层间自旋态铁磁/反铁磁相互作用，揭示轨道上电子自旋状态与缺陷的关系；通过引入不同耦合相互作用，创建新理论模型，阐明畸变双钙钛矿化合物中磁电耦合效应的物理本质。通过第一性原理对畸变双钙钛矿层状化合物的晶体结构、磁电性质进行系统理论模拟，建立化合物的化学键与结构、组分和物理性质的定量关系，从理论上解释畸变钙钛矿结构化合物奇特的磁电性质，从而达到预测和设计合成新型磁电材料的目的。试制成功高迁移率、高介电性、负热膨胀的磁电耦合器件

本项目开展了高压水热法、放电等离子烧结法、诱导磁控溅射法来合成LnPbCoSbO6 (Ln = La, Pr, Nd)，LnPbNiSbO6 (Ln = La, Pr)，LnPbMgSbO6 (Ln = La, Pr, Nd)体系化合物，研究了A位镧系收缩对B位有序双钙钛矿氧化物的晶体结构和磁、介电性质的影响、B位有序双钙钛矿氧化物的晶体结构和磁、介电性质。新型B位有序双钙钛矿氧化物的晶体结构和介电性质，并通过A位不同稀土离子的替换进一步研究了B位晶格畸变对介电性质的影响。采用了不等价取代、自旋注入等方法引入本征缺陷和非本征缺陷；研究了外场作用下的结构畸变引起价态及电子自旋不对称性变化的规律，通过第一性原理的方法对畸变双钙钛矿层状化合物的晶体结构、磁电性质进行系统理论模拟，关联了化合物的化学键与结构、组分和物理性质的定量关系，从理论上解释了畸变钙钛矿结构化合物奇特的磁电性质，达到了预测和设计合成新型磁电材料的目的。