  Electronically phase separated manganite wires are found to exhibit
controllable metal-insulator transitions under local electric fields. The
switching characteristics are shown to be fully reversible, polarity
independent, and highly resistant to thermal breakdown caused by repeated
cycling. It is further demonstrated that multiple discrete resistive states can
be accessed in a single wire. The results conform to a phenomenological model
in which the inherent nanoscale insulating and metallic domains are rearranged
through electrophoretic-like processes to open and close percolation channels.
