Novel Titanium Oxyhydrides (3) : Fabrication and Transport properties of Epitaxial Thin Films

Abstract

Epitaxial thin film of titanium oxyhydride ATiO_3-xH_x (A = Ba, Sr, Ca) were prepared by CaH₂ reduction of epitaxial ATiO₃ thin films deposited on a LSAT substrate. Secondary ion mass spectroscopy detected a substantial amount and uniform distribution of hydride within the film. As opposed to bulk BaTiO_3-xH_x, the electric resistivity of all the ATiO_3-xH_x films exhibited metallic temperature dependence, revealing that the titanium perovskite oxyhydrides are intrinsically metallic. Treatment with D₂ gas results in hydride-deuteride exchange of the films. Combined with the materials' inherent high electronic conductivity, new mixed electron-hydride ion conductors may also be possible.