On-Line Diffusion Tracing in Li Ionic Conductors by the Short-Lived Radioactive Beam of 8Li

A non-destructive and on-line diffusion tracing in Li ionic conductors has been demonstrated. As the tracer, the pulsed beam of the short-lived α-emitting radioisotope of 8Li was implanted into a typical Li ionic conductor LiGa. By analyzing the time-dependent yields of the α-particles measured in coincident with the repetition cycle of the beam, the tracer diffusion coefficients were extracted with a good accuracy. The ordering of the Li vacancies in the Li-deficient β phase of LiGa was observed for the first time in terms of the Li diffusion by the present method.