Nanoelektronik, Technische Fakultät, Christian-Albrechts-Universität zu Kiel, 24143 Kiel, Germany.
Peter Grünberg Institut, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
Nat Commun. 2014 Nov 17;5:5414. doi: 10.1038/ncomms6414.
Among recently discovered ferroelectricity-related phenomena, the tunnelling electroresistance (TER) effect in ferroelectric tunnel junctions (FTJs) has been attracting rapidly increasing attention owing to the emerging possibilities of non-volatile memory, logic and neuromorphic computing applications of these quantum nanostructures. Despite recent advances in experimental and theoretical studies of FTJs, many questions concerning their electrical behaviour still remain open. In particular, the role of ferroelectric/electrode interfaces and the separation of the ferroelectric-driven TER effect from electrochemical ('redox'-based) resistance-switching effects have to be clarified. Here we report the results of a comprehensive study of epitaxial junctions comprising BaTiO(3) barrier, La(0.7)Sr(0.3)MnO(3) bottom electrode and Au or Cu top electrodes. Our results demonstrate a giant electrode effect on the TER of these asymmetric FTJs. The revealed phenomena are attributed to the microscopic interfacial effect of ferroelectric origin, which is supported by the observation of redox-based resistance switching at much higher voltages.
在最近发现的铁电相关现象中，铁电隧道结（FTJ）中的隧道电阻效应（TER）由于这些量子纳米结构在非易失性存储器、逻辑和神经形态计算应用方面的新兴可能性而引起了越来越多的关注。尽管在 FTJ 的实验和理论研究方面取得了最近的进展，但它们的电学行为仍有许多问题尚未解决。特别是，铁电/电极界面的作用以及铁电驱动的 TER 效应与电化学（基于“氧化还原”）电阻开关效应的分离必须加以澄清。在这里，我们报告了由 BaTiO3势垒、La0.7Sr0.3MnO3底电极和 Au 或 Cu 顶电极组成的外延结的综合研究结果。我们的结果表明，这些非对称 FTJ 的 TER 存在巨大的电极效应。所揭示的现象归因于铁电起源的微观界面效应，这一效应得到了在更高电压下观察到的基于氧化还原的电阻开关的支持。
