Variable resistance non-volatile memory element and variable resistance non-volatile memory device using the element

A variable resistance non-volatile memory element, comprising:

• a first electrode;
• a second electrode;
• and
• a variable resistance layer between the first electrode and the second electrode, the variable resistance layer having a resistance value reversibly variable based on an electrical signal applied between the first electrode and the second electrode, wherein
• the variable resistance layer includes:
• a first variable resistance layer that includes a first metal oxide of an oxygen-deficient type, the first metal oxide containing a first metal element and oxygen;
• and
• a second variable resistance layer that includes a composite oxide containing the first metal element, a second metal element different from the first metal element, and oxygen, the composite oxide having a degree of oxygen deficiency different from a degree of oxygen deficiency of the first metal oxide,
• the degree of oxygen deficiency of the composite oxide is lower than the degree of oxygen deficiency of the first metal oxide,
• the composite oxide has, at room temperature, an oxygen diffusion coefficient smaller than an oxygen diffusion coefficient, at the room temperature, of a second metal oxide containing the first metal element and oxygen, and having a degree of oxygen deficiency equal to the degree of oxygen deficiency of the composite oxide, and
• the first variable resistance layer and the second variable resistance layer are both amorphous.