Interrelationship between vanadium diffusion and defects in VO2

Although vanadium ions are known to diffuse through oxygen vacancies, the microscopic diffusing nature is still not clarified. We will therefore plan to measure the following three VO2 samples with muon spin rotation and relaxation: VO2, VO2-d, and VO2+d. When the composition is very close to stoichiometric VO2, vanadium diffusion would be suppressed. On the contrary, such diffusion could be enhanced by oxygen vacancies in VO2-d or vanadium vacancies in VO2+d. Such information is crucial to understand the mass transport in solid oxides and useful to develop novel solid state ionic conductors.