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arXiv · 1703.01422

$\mbox{Rb}_{2}\mbox{Ti}_2\mbox{O}_{5-δ}$: A superionic conductor with colossal dielectric constant

Rémi Federicci·Stéphane Holé·Aurelian Florin Popa·Luc Brohan·Benoît Baptiste·Alexis S. Borowiak·Silvana Mercone·Brigitte Leridon
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Abstract

Electrical conductivity and high dielectric constant are in principle self-excluding, which makes the terms insulator and dielectric usually synonymous. This is certainly true when the electrical carriers are electrons, but not necessarily in a material where ions are extremely mobile, electronic conduction is negligible and the charge transfer at the interface is immaterial. Here we demonstrate in a perovskite-derived structure containing five-coordinated Ti atoms, a colossal dielectric constant (up to $\mbox{10}^9$) together with very high ionic conduction $\mbox{10}^{-3}\mbox{S.cm}^{-1}$ at room temperature. Coupled investigations of I-V and dielectric constant behavior allow to demonstrate that, due to ion migration and accumulation, this material behaves like a giant dipole, exhibiting colossal electrical polarization (of the order of $\mbox{0.1\,C.cm}^{-2}$). Therefore, it may be considered as a "ferro-ionet" and is extremely promising in terms of applications.

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Rémi Federicci, Stéphane Holé, Aurelian Florin Popa, Luc Brohan, Benoît Baptiste, Alexis S. Borowiak, Silvana Mercone, Brigitte Leridon. 2017-03-04. $\mbox{Rb}_{2}\mbox{Ti}_2\mbox{O}_{5-δ}$: A superionic conductor with colossal dielectric constant. https://doi.org/10.1103/physrevmaterials.1.032001

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