Analysis of Multi Length Scale Ordering in Compositionally Complex Rare Earth Titanate Pyrochlores Through Microscopy and Scattering Techniques

In compositionally complex materials with extremely diverse elemental makeups, understanding the effects of chemical ordering and elemental segregation is vital to developing single phase materials with desirable properties for new and emerging material applications. Commonly used techniques such as Energy Dispersive X-Ray Spectroscopy (EDXS) maps provide a qualitative view on the homogeneity of samples through the mapping of elemental distribution. More quantitative means of investigating ordering effects such as X-Ray Absorption Spectroscopy (XAS) and Pair Distribution Function (PDF) analysis are generally measures of ordering in the bulk material. Through the statistical analysis of elemental distributions from EDXS spectrum maps it is possible to get quantitative but sparse information about the ordering of elements at different length scales. With this space and length scale based information on ordering can be combined with property mapping techniques such as scanning probe microscopy or micro/nanohardness mapping. This provides further insight into the effects of ordering on material properties. The current progress on developing this method will be shown through a study on multicomponent rare earth titanate pyrochlores ([nRE]2/nTi2O7 n = 2-5) that were investigated using a combination of electron microscopy EDXS, synchrotron PDF and XAS, neutron PDF, atomic force microscopy, and hardness mapping.