Interfacial\nIon Intermixing Effect on Four-Resistance States in La_0.7Sr_0.3MnO₃/BaTiO₃/La_0.7Sr_0.3MnO₃ Multiferroic Tunnel Junctions

Abstract

A multiferroic tunnel\njunction (MFTJ), employing a ferroelectric barrier layer sandwiched\nbetween two ferromagnetic layers, presents at least four resistance\nstates in a single memory cell and therefore opens an avenue for the\ndevelopment of the next generation of high-density nonvolatile memory\ndevices. Here, using the all-perovskite-oxide La_0.7Sr_0.3MnO₃/BaTiO₃/La_0.7Sr_0.3MnO₃ as a model MFTJ system, we demonstrate asymmetrical\nMnTi sublattice intermixing at the La_0.7Sr_0.3MnO₃/BaTiO₃ interfaces by direct local\nmeasurements of the structure and valence, which reveals the relationship\nbetween ferroelectric polarization directions and four-resistance\nstates, and the low temperature anomalous tunneling behavior in the\nMFTJ. These findings emphasize the crucial role of the interfaces\nin MFTJs and are quite important for understanding the electric transport\nof MFTJs as well as designing high-density multistates storage devices.