The systems Nb 2 O 5 -Ta 2 O 5 and Nb 2 O 5 -V 2 O 5 were investigated using thermal analysis, X-ray powder diffraction and thermodynamic simulations. Solid solution formation is possible for both systems; furthermore, both contain one intermediate compound, VNb 9 O 25 or Ta 2 Nb 4 O 15 , respectively. Phase relationships for pure niobium(V)-oxide and tantalum(V)-oxide were studied under ambient pressure. It was found that both compounds can occur in two stable solid modifications. For niobium(V)-oxide this are the monoclinic high-temperature modification (H-Nb 2 O 5 ) and an orthorhombic low-temperature modification (T-Nb 2 O 5 ) and for tantalum(V)-oxide a tetragonal high-temperature form (α-Ta 2 O 5 ) and an orthorhombic low-temperature form (β-Ta 2 O 5 ). Based on these results, crystal growth experiments with various compositions from both systems were carried out using the optical floating zone (OZF) technique.
TbxGd1−xScO3 and TbxDy1−xScO3 solid-solution single crystals were grown by the Czochralski method to validate the practicality of solid solutions between neighboring RE scandates (REScO3).
High-temperature thermal properties of three neighboring rare-earth scandates DyScO 3 , TbScO 3 and GdScO 3 were compared to La 0.29 Sr 0.71 Al 0.65 Ta 0.35 O 3 (LSAT) and sapphire. To calculate thermal conductivity, heat capacity and thermal diffusivity were measured by differential scanning calorimetry and laser flash technique, respectively. DyScO 3 and TbScO 3 showed an untypical rise in the thermal conductivity above 900 K, while for GdScO 3 , LSAT and sapphire the expected decrease at elevated temperatures could be observed. These results lead to the proposal of a new type of heat transport by migrating ions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.