Can muons measure F− ion diffusion? Exploring two simple test cases

Over the last decade muons have become established as an effective probe of ionic motion in a wide variety of materials. The primary motivation for
this work has been gaining greater understanding of materials intended to be used in electrochemical cells. There are further cations that may become commercially important in this area in the future, some of which are very promising for study with muons due to their nuclear magnetic moment (such
as Al3+), and others (e.g. Zn2+) where the natural abundance is far too low to make muon study feasible. Among the hitherto unexplored ions, F− sits somewhere in the middle ground in terms of feasibility: it has a sizeable moment but the well-known F–μ–F states have discouraged investigation.
Here we propose to study two prototypical F− ion conductors to investigate whether the muon signal can provide information about F− ion motion consistent with existing bulk results. Our intention is to open up a new area of study for muons and also gain a greater understanding of one way in which F–μ–F states can be perturbed.