Variable resistance nonvolatile memory element writing method

A variable resistance nonvolatile memory element writing method for writing data to a variable resistance nonvolatile memory element including a first electrode, a second electrode, and a variable resistance layer which is disposed between the first electrode and the second electrode, is in contact with the first electrode and the second electrode, and reversibly changes between two resistance states consisting of a high resistance state and a low resistance state, according to an electrical signal applied between the first electrode and the second electrode,

• the variable resistance layer having a stacked structure including:
• a first metal oxide layer which is in contact with the first electrode and comprises a first metal;
• and a second metal oxide layer which is in contact with the second electrode and comprises a second metal, and
• the method comprising:
• (a) changing the variable resistance layer to the low resistance state indicated by a resistance value RL, by applying a negative first voltage to the second electrode, the negative first voltage being negative with respect to the first electrode;
• and
• (b) changing the variable resistance layer to the high resistance state,
• wherein step (b) includes:
• (i) changing a resistance value of the variable resistance layer to a resistance value RH which is larger than the resistance value RL, by applying a positive second voltage to the second electrode, the positive second voltage being positive with respect to the first electrode;
• and
• (ii) changing the variable resistance layer to the high resistance state indicated by a resistance value RH1 which is larger than the resistance value RH, by applying a negative third voltage to the second electrode, after the positive second voltage is applied in step (i), the negative third voltage being negative with respect to the first electrode and being smaller than an absolute value of a threshold voltage for changing the variable resistance layer from the high resistance state to the low resistance state.