金属导电性与铁电极化共存的新型功能材料设计与制备

The main motivation of this proposal is to develop the metallic-ferroelectric coexisting materials as an extension of the metallic materials discipline, addressing the coupling and co-manipulation between metallic conductivity and ferroelectric polarization. In the early stage of this strategy, the design and synthesis of the metallic-ferroelectric coexisting materials will be investigated in targeting not only the resistive switching and photo-voltaic effects. This proposal is devoted to three aspects of materials science and microstructural engineering. First, the electronic phase separation effect in transition metal magnetic materials is utilized to synthesize the microscopic phase-coexisting materials. Second, advanced ferroelectric materials with controlled domain structure and metal-conductive walls are investigated to maximize the resistive switching and photo-voltaic performances. Third, artificial metallic-ferroelectric heterostructures with advanced resistive switching will be prepared. Specific emphasis will be made to highly preferred resistive switching and photo-voltaic properties. More than two or three novel phase-coexisting functional materials, offering the advanced properties, will be synthesized. The present project is of special significance not only for electrically and magnetically functional metallic materials but also marks a substantial step towards the interdiscipline activities of materials science.

本申请尝试将金属材料范畴拓展到金属-铁电共存体系，在微观尺度引入铁电极化与金属相导电输运特及其它物性的耦合调控。作为研发这类材料的第一阶段，本项目着重研究这类金属-铁电共存微结构的电阻阻变与光伏效应。项目目标是通过理论设计和实验探索，(1)利用过渡金属磁性化合物的电子相分离原理，合成具有微观尺度金属-铁电相共存的材料；(2)利用具有金属导电的铁电畴壁，实现铁电畴/导电畴壁共存微结构；(3)生长具有铁电/金属/铁电三明治结构的异质结。深入揭示这三类材料中金属输运与铁电调控行为的物理机制。在此基础上，合成出2-3种具有优异性能的金属-铁电共存新材料，适用于高效阻变与光伏输出。本项目的实施将为推动金属-铁电共存的电、磁功能新材料研究做出贡献，并促进金属与非金属材料学科之间的交叉融合。

本项目围绕铁电金属这一主题，值得总结的代表性成果就四句话：(1) 解惑了一个有关铁电金属LiOsO¬3磁性淬灭的疑难问题，并有助于整个Os氧化物体系的研究。(2) 初步制备成功BaTiO3铁电-金属共存的薄膜，特别是在BaTiO3/SrTiO3体系中揭示了含有空位的SrTiO3可能能够从BaTiO3中夺取氧离子、输送氧空位，导致BTO出现金属导电性。(3) 基于所发展的铁电纳米岛制备技术和改进的定量化PFM表征技术，实现了铁电纳米岛畴结构的可控读写和金属性畴壁导电观测。(4) 揭示了若干新的效应，特别是BiFeO3纳米岛的铁电拓扑中心畴的观测与表征。..除此以外，本项目还在与铁电金属、铁电半导体、多铁性和量子关联体系的物理与材料研究中取得若干成果，在此不再一一罗列。..项目执行五年来，在达成项目核心目标方面取得阶段性成果，自我评估为已达成项目目标。项目资助下共发表论文49篇(不完全统计)，包括Adv. Mater和Adv. Funct. Mater.论文7篇、Nature Commun.论文2篇、Sci. Adv.论文1篇、Phys. Rev. B和Phys. Rev. Applied论文8篇、Appl. Phys. Lett.论文9篇。研究工作在国际上有一定影响。在本项目资助下，参加国内外相关学术会议并作邀请报告6次。