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

Abstract

The multiferroic properties of ferroelectric tunnel junctions with a composite barrier comprising a fully epitaxial La 0.7Sr 0.3MnO 3/BaTiO 3/SrTiO 3/La 0.7Sr 0.3MnO 3 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.