Design, synthesis and characterization of multi-ferroic materials - from inhomogeneous nanostructure to functional macroscopic properties

本提案描述了对一类重要无机功能材料（多）铁性材料的设计、合成和表征的综合研究计划，包括压电/铁电材料（具有机电耦合和可切换极化）、铁磁材料（具有可切换磁化）、铁弹性材料（具有可切换应变/变形）和铁磁电材料（具有同时和耦合极化和磁化）。这些材料在广泛的工业或商业应用中都很有用，例如，作为未来计算机中的非易失性随机存取存储器设备，用于主动控制振动或噪声的“智能”传感器和执行器，用于医学成像、诊断和治疗的高分辨率超声波探头，以及微机电系统（MEMS）。这些应用所必需的铁性和多铁性特性源于材料的微观和纳米级晶体化学，即组成离子和化学键的性质，原子和自旋排列（核和磁结构），以及相关的相成分和转变。因此，了解微/纳米结构与宏观功能特性之间的关系是铁材料研究的核心，正是沿着这条线建立了我们的研究计划。

This proposal describes a comprehensive research program on the design, synthesis and characterization of an important class of inorganic functional materials, the (multi-)ferroic materials, including piezoelectrics/ferroelectrics (with electromechanical coupling and switchable polarization), ferromagnetics (with switchable magnetization), ferroelastics (with switchable strain/deformation), and ferro-magnetoelectrics (with simultaneous and coupling polarization and magnetization). These materials are useful in a vast range of industrial or commercial applications, e.g. as nonvolatile random-access memory devices in future computers, 'smart' sensors and actuators for active control of vibration or noise, high-resolution ultrasonic probes for medical imaging, diagnosing and treatment, and micro-electromechanical systems (MEMS). The ferroic and multi-ferroic properties essential to these applications result from the microscopic and nanoscopic crystal chemistry of materials, i.e. the nature of constituent ions and chemical bonding, the atomic and spin arrangements (nuclear and magnetic structures), and the related phase components and transitions. Therefore, understanding the relationship between micro-/nanoscopic structure and macroscopic functional properties is central to the ferroic materials research, and it is along this line that our research program is established.