Novel Oxide-Based Magneto-Electric Tunnel Junctions

本研究的目的是制作和研究磁性隧道结与有源多铁性或铁电势垒-称为磁电隧道结。传统的磁性隧道结代表了一类利用电子自旋来实现其性能的器件。所提出的磁电隧道结是基于理论预测，已确定不对称性作为获得多功能器件的基本标准。这些器件有望同时表现出磁阻和电阻效应，以及微妙的电子输运效应。一个全面的研究计划计划，解决与以下组件相关的问题：样品制造，结构表征，纳米磁电性能，和设备表征。该计划的基本重点是研究具有超薄铁电和多铁性势垒及其复合材料的磁电隧道结的磁电输运性质。该研究的智力价值在于利用对电子特性的基本见解以及创新的制造和表征方法来研究新型异质结构，这些方法有可能实现一类新的多态电阻器件。最先进的脉冲激光沉积技术应与单元控制一起使用，以制造原型器件。应在纳米级和全球水平上研究器械特性。纳米尺度表征将涉及使用导电原子力显微镜的双层结构的电流-电压特性。利用压电响应力显微镜研究超薄膜的局域铁电开关特性。高级扫描探针表征调查纳米级铁电性和隧穿性能应在橡树岭国家实验室的纳米材料科学中心进行。“更广泛的影响”包括一项多学科努力，将对科学知识、教育推广和基础设施作出重大贡献。该项目的科学成果预计将包括新型隧道结结构制造方面的进展以及对其材料和物理特性的基本了解。设备研究将为实现多功能设备提供坚实的基础，如果成功，将产生非凡的影响，并为大量应用打开大门。该计划将为研究生和本科生提供支持，包括代表性不足的少数民族，并有助于他们广泛的跨学科培训。项目人员将与当地学校合作，促进高中生参与研究。

The objective of this research is to fabricate and study magnetic tunnel junctions with an active multiferroic or ferroelectric barrier - termed magneto-electric tunnel junctions. Traditional magnetic tunnel junctions represent a class of device that utilizes the electronic spin for its performance. The proposed magneto-electric tunnel junctions are based on theoretical predictions that have identified asymmetry as a fundamental criterion for obtaining multi-functional devices. These devices are expected to exhibit simultaneous magneto-resistance and electro-resistance effects, coupled with subtle electronic transport effects. A comprehensive research program is planned which addresses issues related to the following components: sample fabrication, structural characterization, nanoscale magneto-electric properties, and device characterization. The basic focus of the proposed program will be on the investigation of magneto-electric transport properties of magneto-electric tunnel junctions with ultra-thin ferroelectric and multiferroic barriers and their composites. The intellectual merit of the research lies in the investigation of novel heterostructures utilizing fundamental insight into electronic properties coupled with innovative fabrication and characterization methods that have the potential for realizing a new class of multiple-state resistance devices. State-of-the-art pulsed laser deposition techniques shall be used with unit-cell control to fabricate prototype devices. Device characteristics shall be investigated both at the nanoscale and global level. Nanoscale characterization would involve current-voltage characteristics of bilayer structures using conducting atomic force microscopy. Local ferroelectric switching properties of ultra-thin films shall be studied using piezoresponse force microscopy. Advanced scanning probe characterization investigating nanoscale ferroelectricity and tunneling properties shall be performed at the Center for Nanoscale Material Sciences at the Oak Ridge National Laboratory. The Broader Impacts includes a multidisciplinary effort that will make significant contributions to scientific knowledge, education outreach and infrastructure. The scientific outcomes of the project are expected to include both advances in the fabrication of a new class of tunnel junction structures and fundamental understanding of their materials and physical characteristics. Device studies will provide a firm foundation for realizing multifunctional devices and, if successful, would have an extraordinary impact and open the door for a plethora of applications. The program will provide support for graduate and undergraduate students, including underrepresented minorities, and contribute to their broad interdisciplinary training. Project personnel will collaborate with local schools to facilitate participation by high school students in research.