Toward intrinsic functionalities of bilayered ruthenate Sr3Ru2O7

Polymorphic materials are known for being prone to intergrowth. Remarkable examples are strontium ruthenates whose properties are dramatically tuned by impurities and disorder. In particular, Sr3Ru2O7 shows a strong variation in transport and magnetic properties depending on synthesis process. It is therefore crucial to correlate atomic structure and properties to identify the functionalities of individual nanostructural constituents. We report a comparative study between Sr3Ru2O7 crystals grown as single phase and in Sr3Ru2O7-Sr2RuO4 eutectics. Our analysis by transmission electron microscopy reveals that Sr3Ru2O7 domains of the eutectic have a significantly lower level of impurities compared to Sr3Ru2O7 single-phase crystals, where intergrowths of Sr4Ru3O10 and SrRuO3 phase are seen. This is confirmed by magnetic measurements. These results identify the eutectic solidification as a fruitful way to grow highly pure crystals of polymorphic materials which, in combination with recent technological developments allowing the extraction of embedded features of crystals, opens a pathway for understanding of their physical properties and applications.