Mechanics of Multiferroic Composites for Strong Magnetoelectric Coupling

该项目的目标是通过由铁电相和铁磁相组成的多铁性复合材料的路线来寻求最强的可能的磁电耦合。这一想法源于人们认识到单相多铁性材料是罕见的，并且在现有的材料中，它们的磁电耦合通常很弱。另一方面，多铁性复合材料可以通过它们共同的机械特性提供强的磁电相互作用。在这项研究中，我们将探索通过相场法和微观力学相结合的最大潜力为散装和纳米结构的多铁性复合材料。我们将应用开发的复合模型来调整它们的体积浓度，相连接性和属性对比度，以实现这一目标。将确定复合材料在外部磁场下的总体极化和其在外部电场下的总体磁化，以评估磁电耦合。在这个过程中，铁电畴和磁畴的演化也将被揭示出来。我们打算考虑BaTiO 3-CoFe 2 O 4复合材料在很大的细节，与1-3，2-2，0-3，3-3的散装连接，1-3和2-2的纳米结构薄膜。以这种方式，可以量化每个连接性图案以及所有图案的最大磁电耦合。 具有强磁电耦合的多铁性材料具有广泛的应用，需要机械能、电能和磁能的交换和相互作用。例如，在信息存储中，耦合允许数据以电子方式写入并以磁性方式读取，从而避免了创建高局部磁场来写入的需要。这类材料也被广泛认为是有用的致动器，传感器，换能器和高频设备，其属性需要电或磁调谐。在微电子学中，片上集成也需要使用许多纳米尺度的多铁性材料。这项工作将对新的高端设备的开发产生直接影响。 我们打算利用这个机会教育一些高中生、本科生和研究生。PI将与TARGET（罗格斯大学工程和技术女孩学院）建立一个暑期项目，以提高他们的认识。他将招募有动力的本科生加入荣誉J. J.斯莱德学者计划（需要论文），并提供多学科培训的研究生与一个新的课程，多铁性材料力学，每周一次的研讨会。将积极招收少数民族、妇女和经济困难学生。研究结果将通过出版物、讲座和网站向公众公开。

The goal of this project is to seek the strongest possible magnetoelectric coupling through the route of multiferroic composites that consist of a ferroelectric and a ferromagnetic phase. This idea grew out of the realization that single-phase multiferroic materials are rare, and among the existing ones their magnetoelectric coupling is generally weak. On the other hand a multiferroic composite could deliver strong magneto-electric interactions through their commonly shared mechanical characteristics. In this research, we will explore the maximum potential through a combination of micromechanics and phase-field approaches for both bulk and nanostructured multiferroic composites. We will apply the developed composite models to tune their volume concentrations, phase connectivity, and property contrast, to achieve this goal. The overall polarization of the composite under an external magnetic field, and its overall magnetization under an external electric field, will be determined to assess the magnetoelectric coupling. In this process the evolution of ferroelectric and magnetic domains will also be uncovered. We intend to consider BaTiO3-CoFe2O4 composites in great details, with the 1-3, 2-2, 0-3, and 3-3 connectivity for the bulk, and 1-3 and 2-2 for nanostructured thin films. In this way the maximum magnetoelectric coupling for each connectivity pattern, and for all patterns, can be quantified. Multiferroic materials with strong magnetoelectric coupling have a wide range of applications that require the exchange and interaction of mechanical, electrical, and magnetic energies. In information storage, for instance, coupling allows the data to be written electronically and read magnetically, thus avoiding the need to create a high local magnetic field to write. This class of materials is also widely known to be useful as actuators, sensors, transducers, and high-frequency devices whose properties need to be tuned electrically or magnetically. In microelectronics, the on-chip integration also demands the use of many nano-scaled multiferroics. This work will have direct impact to the development of new high-end devices. We intend to use this opportunity to educate some high school and undergraduate and graduate students. The PI will establish a summer program with TARGET (The Academy at Rutgers for Girls in Engineering and Technology) to increase their awareness. He will enlist the motivated undergraduates to join the Honor J.J. Slade Scholar Program (which requires a thesis), and provide multidiscipline training to the graduate students with a new course, Mechanics of Multiferroic Materials, and a weekly seminar. Minority, women, and economically underprivileged students will be actively recruited. The results will be made open to the public through publications, lectures, and a website.