Reversible oxygen vacancies doping in (La$_{0.7}$,Sr$_{0.3}$)MnO$_3$ microbridges by combined self-heating and electromigration

Abstract

Combination of electric fields and Joule self-heating is used to change the oxygen stoichiometry and promote oxygen vacancy drift in a free-standing $\mathrm{(La,Sr)MnO_3}$ thin film microbridge placed in controlled atmosphere. By controlling the local oxygen vacancies concentration, we can reversibly switch our LSMO-based microbridges from metallic to insulating behavior on timescales lower than 1 s and with small applied voltages (<5 V). The strong temperature gradients given by the microbridge geometry strongly confine the motion of oxygen vacancies, limiting the modified region within the free-standing area. Multiple resistive states can be set by selected current pulses that determine different oxygen vacancies profiles within the device . Qualitative analysis of device operation is also provided with the support of Finite Element Analysis.