Multiferroic Tunnel Junction with Active Dual Layer Barrier

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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.