In situ TEM studies of oxygen vacancy migration for electrically induced resistance change effect in cerium oxides.

Oxide materials with resistance hysteresis are very promising for next generation memory devices. However, the microscopic dynamic process of the resistance change is still elusive. Here, we use in situ transmission electron microscopy method to study the role of oxygen vacancies for the resistance switching effect in cerium oxides. The structure change during oxygen vacancy migration in CeO2 induced by electric field was in situ imaged inside high-resolution transmission electron microscope, which gives a direct evidence for oxygen migration mechanism for the microscopic origin of resistance change effect in CeO2. Our results have implications for understanding the nature of resistance change in metal oxides with mixed valence cations, such as fluorite, rutile and perovskite oxides.