Magnetostrictive-Piezoelectric Nanocomposites with Unusual Magnetoelectric Properties

技术支持：多铁性材料具有两种或两种以上耦合电场和磁场的有序结构，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。由于磁致伸缩相和压电相组成的多铁性复合材料具有比单相材料大得多的磁致伸缩系数，但其微观结构难以控制，严重限制了其发展。在这个项目中，PI将开发磁致伸缩压电纳米复合材料（MPNC）使用新的纳米光刻为基础的方法，它允许一个工程师的大小，形态和纳米级填料的分布精确地在磁致伸缩或压电矩阵。这种纳米结构工程将使PI能够设计和优化MPNC与不寻常的材料对称性和显着增强ME耦合。本论文的主要研究目标是：（1）开发新型纳米复合材料加工技术，利用纳米压印光刻（NIL）和软光刻（SL）技术精确控制磁致伸缩或压电基体中第二相纳米填料的尺寸、形貌和分布;将使用NIL或SL使基质图案化，然后将其用作模板以存款具有设计尺寸，形态，三维纳米结构复合材料将使用这些技术进行处理，重点是基于TbDyFe合金，PVDF聚合物和PZT陶瓷的材料;（2）用最佳设计的填料尺寸、形态和分布处理MPNC，以获得不寻常的材料对称性和显著增强的ME性能，在PI的理论建模和模拟的指导下，使用能量最小化方法和均匀化理论;（3）表征MPNC在多个长度尺度下的微观结构现象和ME特性，并验证理论建模和模拟。非技术性：教育和推广活动紧密结合到研究中，包括在综合研究和教育计划中培训研究生;通过华盛顿大学的本科研究计划每年培训本科生;以及为K-12教师和学生设计一套简单的纳米压印实验，以传达纳米技术的关键概念。纳米光刻使复合材料加工可以导致具有优化功能的纳米结构设计的设备和系统。该综合研究，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理解，并吸引和培养纳米技术战略重要领域的下一代劳动力。

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.