Functionally Graded Ferroics and Magnetoelectric Interactions

摘要铁材料是一类重要的功能材料，其物理性质对电场和磁场的变化非常敏感。多铁性材料是一种具有两种或两种以上主要铁性（铁磁性、铁电性、铁弹性）的材料。铁磁和铁电材料的复合材料将允许由机械力介导的磁和电子系统之间的耦合，并且是磁电（ME）多铁性。这种复合材料为ME耦合的物理研究提供了机会，并且具有巨大的新型器件潜力。这个项目将把磁电相互作用的研究扩展到梯度铁的新前沿。近年来对组成梯度铁磁体和铁电体的研究发现了内部电位、诱导各向异性和自发应变等新现象。计划的工作将包括合成铁氧体和铁电体的功能分级双层和多层，以及研究分级的影响和ME相互作用的性质。分级将涉及铁氧体中的压磁耦合和铁电体中的压电系数，并将通过化学成分分级来完成。在1mhz范围内进行ME相互作用的研究？包括机电、铁磁和磁声共振的低频效应和耦合。博士后研究助理、研究生和本科生以及高中实习生将参与研究。还计划在技术转让方面与工业界合作。该项目研究的是能够将电能转化为磁能的复合材料，在能量收集、能量存储和消费电子领域具有巨大的应用潜力。这种复合材料将有两个组成部分，它们分别对电场或磁场作出反应，产生机械变形。该项目旨在调整两相的特性，以改善机械响应，从而提高能量转换效率。以可控的方式改变每一相的化学成分是实现这些目标的途径。将合成具有组成变化的单个相和复合材料，并根据能量转换的重要性质进行表征。博士后研究助理、研究生和本科生以及高中实习生将参与研究。还计划在技术转让方面与工业界合作。

Technical AbstractFerroics form an important sub-group of functional materials whose physical properties are sensitive to changes in electric and magnetic fields. A multiferroic is a material that exhibits two or more of the primary ferroic properties (ferromagnetism, ferroelectricity, ferroelasticity). A composite of ferromagnetic and ferroelectric materials will allow coupling between magnetic and electric subsystems that is mediated by mechanical forces and is a magneto-electric (ME) multiferroic. Such composites provide the opportunity for studies on the physics of ME coupling and have enormous potential for novel devices. This project will expand research on magneto-electric interactions to the new frontier of graded ferroics. Recent studies on compositionally graded ferromagnets and ferroelectrics have discovered new phenomena including internal potentials, induced anisotropy, and spontaneous strains. The planned efforts will involve the synthesis of functionally graded bilayers and multilayers of ferrites and ferroelectrics and studies on the effects of grading and the nature of ME interactions. The grading will involve piezomagnetic coupling in ferrites and piezoelectric coefficient in ferroelectrics and will be accomplished by grading the chemical composition. Studies on ME interactions will be done over 1 mHz ? 110 GHz including low-frequency effects and coupling at electromechanical, ferromagnetic and magnetoacoustic resonances. Postdoctoral research associates, graduate and undergraduate students and high school interns will participate in the research. Collaboration with industry is also planned for technology transfer.Non-Technical AbstractThis project is on composite materials that are capable of converting electrical energy to magnetic energy and have enormous potential for use in energy harvesting, energy storage and consumer electronics. The composite will have two components that respond individually to electric or magnetic field by producing a mechanical deformation. The project is aimed at tailoring properties of the two phases to accomplish improved mechanical response, and therefore, enhancement in the energy conversion efficiency. Changes in the chemical composition of each phase in a controlled manner are the avenue that will be explored to achieve these goals. Individual phases and composites with composition variations will be synthesized and characterized in terms of properties of importance for energy conversion. Postdoctoral research associates, graduate and undergraduate students and high school interns will participate in the research. Collaboration with industry is also planned for technology transfer.