Materials World Network: Self-Assembled Nanocomposite Magnetoelectric Thin Films

该材料世界网络(MWN)项目致力于开发具有强磁电耦合的自组装磁电纳米复合薄膜的新型低温湿化学处理方法。磁电效应定义为介质极化在外加磁场作用下的变化，或在外加电场作用下感应磁化的存在。磁电效应及其材料在电调谐磁微波器件、超灵敏磁场传感器、固态变压器等方面具有丰富的基础科学和潜在的应用价值。与单相磁电材料相比，具有铁电和铁磁/铁磁相的磁电复合材料具有更强的磁电耦合以及对铁电相和铁磁/铁磁相的性质进行独立调节的能力。Me薄膜对于单片微波集成电路(MMIC)技术的应用是必不可少的。然而，现有的大多数ME复合材料的合成方法都是块体材料，不能很容易地推广到薄膜。在多层ME复合薄膜中，磁电耦合通常很弱，而在具有三维耦合微结构的纳米复合薄膜中，ME耦合要强得多。到目前为止，关于ME纳米复合薄膜的已发表工作还很有限。南京大学固体微结构国家实验室铁电材料课题组中国和东北大学微波磁性材料与集成电路中心课题组的这项合作，构成了ME复合材料的强大、协同的力量配对。南京集团将开发用于3D耦合ME纳米复合薄膜的Sol-Gel湿化学工艺；而东北集团将开发用于3D耦合ME纳米复合薄膜的低温旋转喷雾湿化学工艺。南京小组将专注于直流和亚兆赫频率的ME效应的表征，而东北小组将专注于RF/微波频率的ME耦合。此外，东北集团将用不同的技术在不同的长度尺度上表征复合材料。南京集团和东北集团将共同建立对湿化学合成ME纳米复合薄膜工艺-结构-性能关系的理解。国家固态微结构实验室和微波磁性材料和集成电路中心之间拟议的合作将带来在CMOS/BiCMOS和MMIC技术中使用ME薄膜的巨大机会，以及尚未考虑的新器件和功能。同时，这一MWN建议将使学生和初级研究人员积极参与国际研究经验。该奖项由国际科学与工程办公室东亚-太平洋项目共同资助。

This Materials World Network (MWN) project is a combined effort to develop novel low-temperature wet-chemical processing methods for self-assembled magnetoelectric (ME) nanocomposite films having strong ME coupling. The magnetoelectric effect is defined as the variation of dielectric polarization under an applied magnetic field, or the presence of an induced magnetization under an external electric field. The ME effect and materials are rich in both fundamental sciences and potential applications such as electrically tunable magnetic microwave devices, ultra-sensitive magnetic field sensors, solid state transformers, etc. Compared to single phase ME materials, magnetoelectric composite materials with ferroelectric and ferrimagnetic/ ferromagnetic phases have the advantages of much stronger ME coupling and the capability of independent tuning of the properties of the ferroelectric phase and the ferromagnetic/ferrimagnetic phase. ME films are essential for applications in CMOS/BICMOS, or monolithic microwave integrated circuits (MMIC) technologies. However, most of the available methods for synthesizing ME composites are for bulk materials, and cannot be readily extended to thin films. Magnetoelectric coupling is typically weak in multilayered ME composite films, whereas in nanocomposite films having 3-dimensional coupled microstructures the ME coupling is much stronger. Up until now, there has been limited published work on ME nanocomposite films. This collaborative effort between the ferroelectric materials group in the National Laboratory of Solid State Microstructures at Nanjing University, China, and the groups in Center for Microwave Magnetic Materials and Integrated Circuits at Northeastern University constitutes a strong, synergistic pairing of strength on ME composite materials. The Nanjing group will develop a sol-gel wet chemical process for 3-D coupled ME nanocomposite films; while the Northeastern groups will develop a low-temperature spin-spray wet chemical process for 3-D coupled ME nanocomposite films. The Nanjing group will focus on the characterization of the ME effects at DC and sub-MHz frequencies; while the Northeastern groups will focus on the ME coupling at RF/microwave frequencies. In addition, the Northeastern groups will characterize the composites at different length scales with different techniques. Together the Nanjing group and the Northeastern groups will establish the understanding on the processing- structure-property relationship in wet-chemical synthesized ME nanocomposite films. The proposed collaboration between the National Laboratory of Solid State Microstructures and the Center for Microwave Magnetic Materials and Integrated Circuits will lead to great opportunities for utilizing ME films in CMOS/BICMOS, and MMIC technologies, as well as novel devices and functionalities not yet considered. At the same time, this MWN proposal will enable active participation of students and junior researchers in international research experiences. This award is co-funded by the East Asia-Pacific Program of the Office of International Science and Engineering.