| Abstract Scope |
Ba1.33-xCsxTi8-yByO16 (B = Ni, Zn, Al) Hollandite-type oxides with unidirectional tunnels will be the focus of the talk. These materials are generally considered for ion capture and transport, for example in battery technologies and for nuclear waste sequestration, sensors, and sorbents. Beyond the phase transitions from lower to higher symmetry that occur with temperature, we find that there exists superstructure order, including incommensurate ordering in position and occupancy, as a function of chemical composition and temperature. The occupancy of the tunnel with both Cs and Ba ions has not been studied, though it is clear that the ordering depends critically on the Ba/Cs ratios. Examples of ordering during cooling will be shared, with focus on how a critical cooling rate can generally be found which prevents the superstructure ordering, and implications for application of these materials. |