Resistance switching in large-area vertical junctions of the molecular spin crossover complex [Fe(HB(tz))]: ON/OFF ratios and device stability.

Multilayer crossbar junctions composed of ITO/[Fe(HB(1,2,4-triazol-1-yl))]/M (with M  =  Al or Ca) were fabricated and investigated for their resistance switching properties. Current-voltage-temperature maps revealed ON/OFF resistance ratios as high as 400, with the ON and OFF states defined, respectively, as the low-resistance, low spin state and the high-resistance, high spin state of the spin crossover layer. Similar results were obtained with Al and Ca cathodes indicating that the charge transport in the insulating spin crossover film is at the origin of the resistance switching instead of electron injection at the electrodes. The reproducibility and stability of the device properties were also studied.