Magnetic tunnel junctions with a ferroelectric barrier using epitaxial La$_{0.7}$Ca$_{0.3}$MnO$_{3}$/(Ba, Sr)TiO$_{3}$/La$_{0.7}$Ca$_{0.3}$MnO$_{3 }$trilayers

ORAL

Abstract

We have fabricated multiferroic tunnel junctions using ferromagnetic La$_{0.7}$Ca$_{0.3}$MnO$_{3 }$as electrodes and ferroelectric (Ba, Sr)TiO$_{3}$ as the barrier. We have observed tunneling magnetoresistance as in a typical magnetic tunnel junction (MTJ). Since the ferroelectric barrier can be charge polarized in two opposite directions which alters tunneling conductance, we have observed large tunneling electroresistance ($\sim $ 50{\%}) when the charge polarization is switched. This has been observed for both magnetic parallel and antiparallel states. As a result, this type of junctions has four resistance states instead of two for a normal MTJ, corresponding to positive- and negative-polarized parallel and antiparallel states. The four states can be manipulated by the magnetic and electric fields. The dependence of the magnetoresistance and electroresistance as functions of magnetic field, electrical field, and bias voltage will be presented.

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Authors

  • Shengming Guo

    Pennsylvania State University

  • Ke Chen

    Pennsylvania State University, Department of Physics, Pennsylvania State University, University Park, PA 16802, Deparment of Physics, Penn State University, University Park, PA 16802

  • X.X. Xi

    Pennsylvania State University, Department of Physics, Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, The Pennsylvania State University, Department of Physics and Department of Materials Science and Engineering, Penn State University, University Park, PA 16802

  • Qi Li

    Pennsylvania State University, Department of Physics, Pennsylvania State University, University Park, PA 16802, Deparment of Physics, Penn State University, University Park, PA 16802

  • Yonggang Zhao

    Tsinghua University