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”，这种材料具有不可思议的能力，可以通过以可逆的方式突然改变其特性来响应外部刺激。同时表现出磁性和铁电有序的多铁质材料是潜在的智能材料。虽然这些化合物中的磁有序和铁电性之间的相互作用目前是凝聚态物理中尚未解决的基本问题之一，但两种有序同时发生的情况很少见，而且通常发生在低温下。最近在室温下具有良好多铁性的薄膜和纳米结构材料的出现是一个转折点，为将多铁性/磁电材料应用于传感、能量转换、光子学和电信高频电子学等领域的新型集成器件开辟了道路。该研究项目将专注于研究单相和原位成形纳米复合材料系统，这些系统在室温下具有多铁性。它将集中研究它们的磁电耦合以及它们的高频动态行为，这是应用的关键特性。本课组所发现和开发的铋基双钙钛矿的室温多铁外延薄膜和原位生成的多铁纳米复合材料将得到进一步的研究，同时还将研究新的室温多铁体系，如掺杂铋铁氧体和四方钨青铜/钡铁氧体。将合成并研究室温磁电薄膜，制作概念验证器件。最后，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个纤维的机电性能，这是基于加拿大和世界上丰富资源的廉价新型压电技术材料的一步。该研究项目将为当今多铁性和磁电智能材料领域的前沿研究提供一个刺激的培训环境。

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.