Asymmetric electromigration-driven resistive switching in tunnel junctions

Abstract

Devices displaying resistive-switching are being researched as possible candidates for non-volatile Random Access Memories. Here we study resistance ( R) switching of non-magnetic origin on CoFe/AlO x /CoFe tunnel junctions. We observe R-switching to a low state for negative currents (top to bottom lead) only, here associated with electromigration (EM) of ions from the bottom metallic electrode into the insulator. EM in the reverse sense occurs only for positive current. We thus show the existence of asymmetric electromigration between the two electrode/barrier interfaces, likely reflecting their structural differences.