Writing for IEEE Spectrum, Alexander Hellemans notes that researchers have thus far produced two commercially promising types of memristors: electrochemical metallization memory (EMC) cells and valence change mechanism memory (VCM) cells.
“In EMC cells, which have a copper electrode (called the active electrode), the copper atoms are oxidized—stripped of an electron—by the ‘write’ voltage,” he explained. “The resulting copper ions migrate through a solid electrolyte towards a platinum electrode. When they reach the platinum they get an electron back. Other copper ions arrive and pile on, eventually forming a pure metallic filament linking both electrodes, thus lowering of the resistance of the device.”

