Multiferroic Tunnel Junction with Active Dual Layer Barrier

该项目由材料研究部（DMR）的电子和光子材料计划（EMT）和陶瓷计划（CER）共同资助。非技术描述纳米铁电子学（Nanoferronics）是一个新概念，它将具有自发电荷极化的铁电体与利用电子自旋传输和存储信息的自旋电子学相结合。这些新概念可以用作具有包括电控制自旋的新功能的多级多功能装置。该项目解决了一个主要的材料挑战，即如何增加多铁性隧道结的电阻开-关比，这是一个纳米铁电子概念，通过将非常薄的铁电绝缘体和界面层作为磁性隧道结的屏障，用于磁记录和非易失性存储器。研究的成功可能会对实现新的设备概念，特别是组合式处理器上存储器方法产生重大影响。该项目的教育目标是为研究生和本科生提供教育和培训机会，特别是为女性和代表性不足的少数民族本科生提供教育和培训机会，并为物理学，材料科学和工程学的跨学科经验提供激励环境。PI有多年的经验，建议女性和代表性不足的群体，通过几个既定的方案在校园，并将继续在这些活动。技术说明多铁性隧道结结合联合收割机磁性隧道结与铁电隧穿，并已显示出许多有前途的功能，可以把逻辑和存储器到一个设备。本计画的目的是设计并制作一个双层铁电隧道结，其中一层为铁电势垒层，另一层为界面层。更具体地说，通过设计屏障界面，可以触发界面处的相变并充当电流滤波器来调节开和关状态。 两个主要目标是（1）增加隧穿电阻，电阻开关比，和（2）实现通过电场控制磁状态。利用第二阻挡层，可以通过铁电驱动界面相变实现电阻比的大得多的增强。通过结合不同的磁性和铁电氧化物的异质结构的设计和控制生长，界面状态的测量，以及器件的磁性和传输特性的测量，该项目旨在了解界面效应在增强隧道电阻和磁电相互作用中的机制。

This project is jointly funded by the Electronic and Photonic Materials Program (EPM) and Ceramics Program (CER) in the Division of Materials Research (DMR). Nontechnical Description Nanoferronics is a new concept that combines ferroelectrics, which has spontaneous charge polarization, with spintronics, which utilize the electron spins to transport and store information. These new concepts can be used as multilevel multifunctional devices with new functionalities including electric control of spins. The project addresses a major materials challenge on how to increase the resistance on-and-off ratio of multiferroic tunnel junctions, a nanoferronic concept, by combining a very thin ferroelectric insulator and an interface layer as the barrier with magnetic tunnel junctions which have been used for magnetic recording and non-volatile memories. Success of the research can have significant impacts on realizing the new device concept and especially the combined memory-on-processor approach. The educational goals of the project are to provide educational and training opportunities for both graduate and undergraduate students, especially for female and underrepresented minority undergraduate students, with a stimulating environment for interdisciplinary experience in physics, materials sciences, and engineering. The PI has many years of experience in advising female and underrepresented groups through several established programs on campus and will continue in those activities.Technical DescriptionMultiferroic tunnel junctions combine magnetic tunnel junction with ferroelectric tunneling, and have shown many promising functionalities that can bring logic and memory into one device. The objective of the project is to design and fabricate a dual layer barrier in the multiferroic tunnel junctions with one ferroelectric barrier and a second interfacial layer. More specifically, by designing the barrier interface, a phase transition at the interface may be triggered and serve as a current filter to regulate the on-and-off state. The two major goals are (1) to increase the tunneling electroresistance, the resistance on-off ratio, and (2) to achieve the control of magnetic state by electrical field. With the second barrier layer, a much larger enhancement of the resistance ratio through the ferroelectric driven interface phase transition may be achieved. By combining the design and controlled growth of heterostructures of different magnetic and ferroelectric oxides, measurements of the interfacial states, and measurements of magnetic and transport properties of the devices, the project seeks to understand the mechanisms of the interfacial effect in enhancing tunneling electroresistance and magnetoelectric interaction in several systems.