title: Tunneling electroresistance in multiferroic heterostructures.
abstract: We demonstrate the room temperature polar switching and tunneling in PbZr0.52Ti0.48O3 (PZT) ultra-thin films of thickness 3-7 nm, sandwiched between platinum metal and ferromagnetic La0.67Sr0.33MnO3 (LSMO) layers, which also shows magnetic field dependent tunnel current switching in Pt/PbZr0.52Ti0.48O3/La0.67Sr0.33MnO3 heterostructures. The epitaxial nature, surface quality and ferroelectric switching of heterostructured films were examined with the help of x-ray diffraction patterns, atomic force microscopy, and piezo force microscopy, respectively. The capacitance versus voltage graphs show butterfly loops above the coercive field (> ±3 V) of PZT for small probe area (∼16 μm(2)). The effect of ferroelectric switching was observed in current density versus voltage curves with a large variation in high-resistance/low-resistance (HRS/LRS) ratio (2:1 to 100:1), however, these effects were more prominent in the presence of in-plane external magnetic field. The conductance is fitted with Brinkman's model, and the parabolic conductance upon bias voltage implies electron tunneling governs the transport.
authors.affiliation: Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931-3343, USA.
authors.forename: D
authors.initials: D
authors.lastname: Barrionuevo
authors.forename: Le
authors.initials: L
authors.lastname: Zhang
authors.forename: N
authors.initials: N
authors.lastname: Ortega
authors.forename: A
authors.initials: A
authors.lastname: Sokolov
authors.forename: A
authors.initials: A
authors.lastname: Kumar
authors.forename: Pankaj
authors.initials: P
authors.lastname: Misra
authors.forename: J F
authors.initials: JF
authors.lastname: Scott
authors.forename: R S
authors.initials: RS
authors.lastname: Katiyar