Room Temperature Magnetoelectric & Multiferroic Films and Composites for novel Devices

下一代小型化设备将越来越依赖于“智能材料”，这种材料具有神奇的能力，可以通过以可逆的方式突然改变其特性来响应外部刺激。多铁性，同时表现出磁性和铁电有序，是潜在的这样的智能材料。虽然磁性有序和铁电性之间的相互作用是目前凝聚态物理中尚未回答的基本问题之一，但同时出现这两个有序的情况很少见，而且经常发生在低温下。近年来，在室温下具有良好多铁性的薄膜和纳米结构材料的出现，为将多铁性/磁电性材料应用于新型集成器件开辟了道路，在传感、能量转换以及用于通信的光子学和高频电子学等领域。 这项研究计划将专注于研究在室温下具有多铁性的单相和原位形成的纳米复合材料系统。它将集中研究它们的磁电耦合以及它们的高频动态行为，这些都是应用的关键特性。本课题组发现和发展的铋基双钙钛矿室温多铁性外延薄膜和原位生成的多铁性纳米复合材料还将进一步研究，同时还将研究新的室温多铁性系统，如掺杂铋铁氧体和四方钨青铜/钡铁氧体。利用合成和研究的常温磁电薄膜制作概念验证器件。最后，将利用压电响应力显微镜在纳米尺度上研究纳米晶纤维素单纤维的机电性能，这是基于加拿大和世界上丰富的资源向廉价的新型压电技术材料迈出的一步。 这一研究计划将在当今多铁性和磁电智能材料领域的前沿研究中提供一个激动人心的培训环境。

The next generation of miniaturized devices will increasingly rely on "smart materials", materials with the uncanny ability to respond to an external stimulus by abruptly changing their properties in a reversible manner. Multiferroics, exhibiting at once, a magnetic and a ferroelectric ordering are potentially such smart materials. While the interplay between magnetic ordering and ferroelectricity in these compounds is presently one of the unanswered fundamental questions in condensed matter physics, the occurrence of both orders simultaneously is rare and very often occurs at low temperature. The recent emergence of thin films and nanostructures of materials with good multiferroic properties at room temperature has been a turning point opening the way for using multiferroics/magnetoelectrics into novel integrated devices, in areas such as sensing, energy conversion, as well as photonics and high-frequency electronics for telecommunication. This research program will focus on investigating exclusively single phase and in-situ forming nanocomposites systems that are multiferroic at room temperature. It will concentrate on studying their magnetoelectric coupling as well as their high-frequency dynamic behavior, which are key properties for applications. The room temperature multiferroic epitaxial thin films of the Bi-based double perovskites and in-situ generated multiferroic nanocomposites discovered and developed in my group will be further studied, while new room temperature multiferroic systems will be investigated as well, such as doped bismuth ferrite and tetragonal tungsten bronze/barium ferrite. Proof-of-concept devices will be fabricated with the room temperature magnetoelectric films synthesized and studied. Finally, the electromechanical properties of nanocrystalline cellulose individual fibers will be studied at the nanoscale using piezoresponse force microscopy, a step toward a cheap novel piezoelectric technological materials based on a resource abundant in Canada and in the world. This research program will provide a stimulating training environment at the leading edge of today's research in the field of multiferroic and magnetoelectric smart materials.