Thermal analysis and crystal growth of doped Nb$_2$O$_5$

Julia Hidde; Christo Guguschev; Detlef Klimm

doi:10.1016/j.jcrysgro.2018.12.035

paper

Thermal analysis and crystal growth of doped Nb $_{2}$ O $_{5}$

arXiv:1810.02598 · doi:10.1016/j.jcrysgro.2018.12.035

Abstract

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 (OFZ) technique.

15 pages, 10 figures, 6 tables, submitted to J. Crystal Growth

Thermal analysis and crystal growth of doped Nb2​O5​

Abstract

Thermal analysis and crystal growth of doped Nb $_{2}$ O $_{5}$