Robust Room Temperature Electric Field Control of Structural, Magnetic and Transport Properties of Ultra-Thin Shape Memory Heusler Alloys Films

技术摘要：该项目的目标是展示一类新的纳米铁性多功能器件，该器件基于形状记忆Heusler合金薄膜在铁电异质结中，其中Heusler合金的电阻、磁性和结构特性将通过外加电场进行切换。Heusler合金是一组金属间化合物，具有独特而有趣的电磁行为，包括磁性形状记忆效应。选定的形状记忆Heusler合金有望比锰基化合物更好，因为它们的相变可以控制在室温附近发生。这项研究试图区分异质结中各层之间的电子耦合和应变中介耦合的作用，以确定每种效应的来源。并对Heusler合金薄膜的马氏体相变机制进行了初步探讨。最终的设想是，这项研究可能导致一类新的纳米铁性多功能器件，使其能够实现新的传感器和电子应用。这些设备将有潜力用于存储器、传感器和磁制冷。将加强高中教师及其学生对调查人员研究实验室的长期参与。研究生和本科生将通过研究活动进行教育和培训。非技术总结：将利用Heusler合金薄膜中的磁性形状记忆效应单独探索这些合金的物理行为，并与其他材料组合制成功能器件。最终的设想是，这项研究可能导致一类新的纳米铁性多功能器件，使其能够实现新的传感器和电子应用。这些设备将有潜力用于存储器、传感器和磁制冷。将加强高中教师及其学生对调查人员研究实验室的长期参与。研究生和本科生将学习纳米制造技术、化学合成、灵敏的电测量以及量子传输和磁化动力学理论，为他们在领先的工业和学术实验室进一步研究和开发提供实践经验。

TECHNICAL SUMMARY:The goal of this project is to demonstrate a new family of nanoferroic multifunctional devices, based on shape-memory Heusler alloy films in ferroelectric heterojunctions, where resistance, magnetic and structural properties of the Heusler alloys will be switchable by applied electric field. Heusler alloys are a group of intermetallic compounds that have unique and interesting electro-magnetic behaviors, including the magnetic shape-memory effect. Selected shape-memory Heusler alloys are expected to be better than manganite-based compounds because their transformations can be controlled to occur near room temperature. This research attempts to distinguish the roles of electronic and strain-mediated coupling between layers in heterojunctions in order to determine the origin of each effect. It also attempts to identify the mechanism of the martensitic phase transformation in the Heusler alloy films. It is ultimately envisioned that this research may lead to a new class of nanoferroic multifunctional devices enabling new sensor and electronic applications. These devices will have a potential for use in memory, sensors and magnetic refrigeration. Long-established participation of high-school teachers and their students in the research laboratories of the investigators will be enhanced. Graduate and undergraduate students will be educated and trained through research activities.NON-TECHNICAL SUMMARY:The magnetic shape-memory effect in Heusler alloy films will be used to explore physical behaviors of these alloys alone and when paired with other materials to make a functional device. It is ultimately envisioned that this research may lead to a new class of nanoferroic multifunctional devices enabling new sensor and electronic applications. These devices will have a potential for use in memory, sensors and magnetic refrigeration. Long-established participation of high-school teachers and their students in the research laboratories of the investigators will be enhanced. Graduate and undergraduate students will learn nanofabrication techniques, chemical synthesis, sensitive electrical measurements, and theory of quantum transport and magnetization dynamics, providing hands-on experience suitable for their further research and development in leading industrial and academic laboratories.