title: Chemical insight into electroforming of resistive switching manganite heterostructures.
abstract: We have investigated the role of the electroforming process in the establishment of resistive switching behaviour for Pt/Ti/Pr0.5Ca0.5MnO3/SrRuO3 layered heterostructures (Pt/Ti/PCMO/SRO) acting as non-volatile Resistance Random Access Memories (RRAMs). Electron spectroscopy measurements demonstrate that the higher resistance state resulting from electroforming of as-prepared devices is strictly correlated with the oxidation of the top electrode Ti layer through field-induced electromigration of oxygen ions. Conversely, PCMO exhibits oxygen depletion and downward change of the chemical potential for both resistive states. Impedance spectroscopy analysis, supported by the detailed knowledge of these effects, provides an accurate model description of the device resistive behaviour. The main contributions to the change of resistance from the as-prepared (low resistance) to the electroformed (high resistance) states are respectively due to reduced PCMO at the boundary with the Ti electrode and to the formation of an anisotropic n-p junction between the Ti and the PCMO layers.
authors.affiliation: CNR--Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna, Italy. francesco.borgatti@cnr.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Borgatti
authors.forename: Chanwoo
authors.initials: C
authors.lastname: Park
authors.forename: Anja
authors.initials: A
authors.lastname: Herpers
authors.forename: Francesco
authors.initials: F
authors.lastname: Offi
authors.forename: Ricardo
authors.initials: R
authors.lastname: Egoavil
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Anli
authors.initials: A
authors.lastname: Yang
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kobata
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Jo
authors.initials: J
authors.lastname: Verbeeck
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Panaccione
authors.forename: Regina
authors.initials: R
authors.lastname: Dittmann