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arXiv · 1810.02598

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

Julia Hidde·Christo Guguschev·Detlef Klimm
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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 ($\alpha$-Ta$_2$O$_5$) and an orthorhombic low-temperature form ($\beta$-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.

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Julia Hidde, Christo Guguschev, Detlef Klimm. 2018-10-05. Thermal analysis and crystal growth of doped Nb$_2$O$_5$. https://doi.org/10.1016/j.jcrysgro.2018.12.035

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