Tunneling magnetoresistance and electroresistance properties of composite‐barrier ferroelectric tunnel junctions

The multiferroic properties of ferroelectric tunnel junctions with a composite barrier comprising a fully epitaxial La_0.7Sr_0.3MnO₃/BaTiO₃/SrTiO₃/La_0.7Sr_0.3MnO₃ heterostructure are reported in this study. The patterned junctions having extended top electrodes show tunnel magnetoresistance ratios ranging from 20% to 110% at 77 K. Furthermore, tunneling electroresistance – induced by ferroelectric polarization switching and showing two‐state memory effect in the dynamic resistance – has also been observed in these junctions. Thus, with the concurrence of tunneling electroresistance and magnetoresistance, these tunnel junctions serve as memory devices with four resistance states. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)