Prominent thermodynamical interaction with surroundings on nanoscale memristive switching of metal oxides.

This study demonstrates the effect of surroundings on a memristive switching at nanoscale by utilizing an open top planar-type device. NiO(x) and CoO(x) planar-type devices have exhibited a memristive behavior under atmospheric pressure, whereas TiO(2-x) planar-type devices did not show a memristive switching even under the same surroundings. A memristive behavior of TiO(2-x) planar-type devices has emerged when reducing an ambient pressure and/or employing a SiO(2) passivation layer. These results reveal that a thermodynamical interaction with surroundings critically determines the occurrence of memristive switching via varying a stability of nonstoichiometry. Since this effect tends to be more significant for smaller devices with larger specific surface area, tailoring the surrounding effect by an appropriate passivation will be essential for high density devices.