Patent ID: 7369431

Claim:
A method for utilizing, as a memory device, a material (variable-resistance material) whose resistance value increases/decreases according to the polarity of an applied electric pulse, the method comprising the steps of: (a) in an initial state where the variable-resistance material has not yet been subjected to application of an electric pulse after a film formation, applying an electric pulse having a first polarity at least once between first and second electrodes connected to the variable-resistance material such that the potential of the first electrode is higher than that of the second electrode; (b) uniquely determining a relationship between the polarity of the electric pulse to be applied between the first and second electrodes and the increase/decrease of the resistance value of the variable-resistance material, according to the polarity of the electric pulse applied in the step (a); and (c) changing the resistance value of the variable-resistance material to a desired value by selecting the first polarity or a second polarity where the potential of the first electrode is lower than that of the second electrode, according to the relationship determined in the step (b), and applying an electric pulse having the selected polarity between the first and second electrodes to increase/decrease the resistance value of the variable-resistance material.