Electromigration of oxygen and resistive state transitions in sub-micron width long strip of La[formula omitted]Sr[formula omitted]MnO[formula omitted] connected to an engineered oxygen source

Abstract

Oxygen electromigration studies have been carried out on long and submicron width strips of La0.85Sr0.15MnO3 (LSMO:0.15) film on LaAlO3 substrate with lithographically defined oxygen source created by local electrochemical oxidation. Electromigration by short duration current stressing leads to transition from a high resistance state (HRS) to a metastable low resistance state (LRS) that recovers back after a wait time (tW). Sustained current stressing beyond a critical current leads to irreversible RS transition to a stable LRS. The transition has an Arrhenius type temperature dependence with an activation energy ∼ 0.45–0.55 eV. Heating suppresses the transition and RS vanishes at a temperature T0≥ 375 K. It is suggested that the irreversible transition happens due to phase transition from a higher resistance Jahn-Teller distorted orthorhombic phase (O′) to a undistorted orthorhombic (O) phase which have close proximity at room temperature in LSMO:0.15 and are sensitive to current induced hole doping.