Magnetostrictive-Piezoelectric Nanocomposites with Unusual Magnetoelectric Properties

技术：多铁性材料同时具有两种或两种以上类型的电场和磁场耦合，但单相多铁性材料的磁电耦合系数非常小，使其实际应用几乎不可能。由磁致伸缩相和压电相组成的多铁复合材料具有比单相材料大得多的ME系数，但难以控制复合材料的微观结构严重限制了其发展。在这个项目中，PI将使用基于纳米光刻的新方法开发磁致伸缩-压电纳米复合材料（MPNC），这使得人们可以在磁致伸缩或压电矩阵中精确地设计纳米级填料的尺寸、形态和分布。这种纳米结构工程将使PI能够设计和优化具有不同寻常的材料对称性和显着增强的ME耦合的MPNC。三个研究目标是：(1)利用纳米压印光刻技术（NIL）和软光刻技术（SL）开发新的纳米复合材料加工技术，以精确控制磁致伸缩或压电矩阵中第二相纳米填料的尺寸、形态和分布；将使用NIL或SL对基体进行图图化，然后将其用作模板，以沉积具有设计尺寸、形态和分布的第二相填料；三维纳米结构复合材料将使用这些技术加工，重点是基于TbDyFe合金，PVDF聚合物和PZT陶瓷的材料；(2)在PI理论建模和能量最小化方法及均质化理论模拟的指导下，采用优化设计的填料尺寸、形态和分布来实现不同寻常的材料对称性和显著增强的ME性能；(3)表征多长度尺度下MPNC的微观结构现象和ME特性，验证理论建模和仿真结果。非技术：教育和推广活动与研究紧密结合，包括在综合研究和教育计划中培训研究生；每年通过华盛顿大学本科生研究项目培训本科生；设计一套简单的实验，让K-12的师生了解纳米技术的关键概念。纳米光刻支持的复合加工可以导致纳米结构设计的设备和系统具有优化的功能。综合研究、教育和推广计划将激发K-12和大学生的科学兴趣，促进公众对纳米技术的了解，并在纳米技术这一具有重要战略意义的领域吸引和培养下一代劳动力。

TECHNICAL: Multiferroic materials possess two or more types of orders simultaneouslythat couple the electric and magnetic fields, yet the magnetoelectric (ME) coupling coefficients in single phase multiferroics are extremely small, making their practical applications virtually impossible. Large efforts have been devoted to developing multiferroic composites consisting of magnetostrictive and piezoelectric phases, which could possess much larger ME coefficients than single-phase materials, yet the difficulty in controlling the microstructures of the composites severely limited their development. In this project PI will develop magnetostrictive-piezoelectric nanocomposites (MPNC) using novel nanolithography based approaches, which allows one to engineer the size, morphology, and distribution of nanoscale fillers precisely in a magnetostrictive or piezoelectric matrix. Such nanostructure engineering will enable PI to design and optimize MPNC with unusual material symmetries and dramatically enhanced ME coupling. The three research goals are to: (1) Develop novel nanocomposite processing techniques using nanoimprint lithography (NIL) and soft lithography (SL) to precisely control the size, morphology, and distributions of second-phase nanofillers in a magnetostrictive or piezoelectric matrix; the matrix will be patterned using NIL or SL, which is then used as a template to deposit second-phase fillers with designed size, morphology, and distribution; three-dimensional nanostructured composites will be processed using these techniques, focusing on materials based on TbDyFe alloys, PVDF polymers, and PZT ceramics; (2) Process MPNC with optimally designed fillers size, morphology, and distribution for unusual material symmetries and dramatically enhanced ME properties, guided by PI's theoretical modeling and simulations using energy minimization approach and homogenization theory; and (3) Characterize the microstructural phenomena and ME properties of MPNC at multiple length scales, and validate theoretical modeling and simulations. NON-TECHNICAL: The education and outreach activities are tightly integrated into research, including training graduate student in an integrated research and educational program; training undergraduate student each year through Undergraduate Research Program at University of Washington; and design a set of simple experiments underlying nanoimprinting for K-12 teachers and students to convey the key concepts of nanotechnology. Nanolithography-enabled composite processing could lead to nanostructure-designed devices and systems with optimized functionality. The integrated research, education and outreach program will stimulate scientific interests of K-12 and college students, promote public understanding on nanotechnology, and attract and train next generation of work force in the strategic important field of nanotechnology.