Multiferroic Tunnel Junction with Active Dual Layer Barrier

该项目由材料研究部的电子和光子材料计划(EPM)和陶瓷计划(CER)共同资助。非技术描述纳米铁电子学是一个新概念，它结合了具有自发电荷极化的铁电体和利用电子自旋来传输和存储信息的自旋电子学。这些新概念可以用作多级别多功能设备，具有包括电子控制纺纱在内的新功能。该项目解决了一个主要的材料挑战，即如何通过将非常薄的铁电绝缘体和作为屏障的接口层与用于磁记录和非易失性存储器的磁隧道结相结合，来提高多铁性隧道结的电阻开关比，这是一个纳米铁子概念。研究的成功可以对实现新的设备概念，特别是联合处理器上的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，特别是为女性和少数族裔本科生提供教育和培训机会，为在物理、材料科学和工程学方面的跨学科经验创造一个刺激的环境。多铁隧道结将磁性隧道结和铁电隧道结结合在一起，并展示了许多有前途的功能，可以将逻辑和存储器整合到一个设备中。该项目的目标是设计和制造具有一个铁电势垒和第二界面层的多铁性隧道结中的双层势垒。更具体地说，通过设计势垒界面，可以触发界面处的相变并用作电流过滤器以调节开关状态。两个主要目标是(1)提高隧道电阻、电阻开关比和(2)实现电场对磁场状态的控制。有了第二层势垒层，可以通过铁电驱动的界面相变实现更大的电阻比提高。通过设计和控制生长不同磁性和铁电氧化物的异质结构，测量界面态，以及测量器件的磁性和输运性质，该项目试图了解界面效应在几个系统中增强隧道电阻和磁电相互作用的机制。

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.