Applied Crystallography

Biography

Biography: Werner Paschinger

Abstract

Although hitherto still no phase diagrams exist for the ternary systems Ce_xT_ySn_z (T = Pd or Pt), several compounds of these systems are in the focus of interest due to a number of interesting physical properties. Up to now, they have mainly been characterized by their magnetic properties, but more recently attracted attention due to their possible application as thermoelectric materials. For example, the hybridization of the 4f state of the Ce atom with conduction electrons of T and Sn atoms in Ce₃Pt₃Bi₄ and CeRu₄Sn₆ or Ce₄Pt₁₂Sn₂₅ with complex structures gives rise to a large thermopower, which is one of the prerequisites for thermoelectric application. For a proper interpretation and understanding of physical properties, the knowledge of the compounds’ crystal structure is of high importance. Therefore the relation of physical properties to structural motives in both systems will be discussed and compared to each other. Furthermore, we will introduce the crystal structure of two novel ternary compounds, CePd₃Sn₂ and Ce₃Pt₄Sn₆, derived by direct methods from X-ray single crystal data. Whereas CePd₃Sn₂ crystallizes in an orthorhombic structure, Ce₃Pt₄Sn₆ seems to coexist in a monoclinic and orthorhombic modification. For the monoclinic structure an intrinsically defect growth pattern was found backed by high resolution TEM. Structural units intrinsic to the title systems will be compared as well as to other related defect structures.