VARIABLE RESISTANCE NON-VOLATILE MEMORY ELEMENT AND VARIABLE RESISTANCE NON-VOLATILE MEMORY DEVICE USING THE ELEMENT

A variable resistance non-volatile memory element includes first and second electrodes and a variable resistance layer between the electrodes. The layer has a resistance value reversibly variable based on an electrical signal. The layer includes a first variable resistance layer that includes an oxygen deficient 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, and having a different degree of oxygen deficiency from the first metal oxide. The composite oxide has a lower degree of oxygen deficiency than the first metal oxide. At room temperature, the composite oxide has a smaller oxygen diffusion coefficient than a second metal oxide containing the first metal element and oxygen, and having the degree of oxygen deficiency equal to that of the composite oxide.