Reversible oxygen vacancies doping in (La-0.7,Sr-0.3)MnO3 microbridges by combined self-heating and electromigration

Combination of electric fields and Joule self-heating is used to change the oxygen stoichiometry and promote oxygen vacancy drift in a freestanding (La,Sr)MnO3 thin film microbridge placed in controlled atmosphere. By controlling the local oxygen vacancies concentration, we can reversibly switch our (La,Sr)MnO3-based microbridges from metallic to insulating behavior on timescales lower than 1 s and with small applied voltages (<5V). 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. (C) 2015 AIP Publishing LLC.