  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.
