Different defects formation modes under sevier reducing condition in primitive cubic perovskites, BaZr1-xYxO3-x/2 and BaSn1-xYxO3-x/2

Conference Dates

March 10-14, 2019


Reduction processes using metal hydride agents modify the chemical and structural properties of metal oxide crystals with different manners, depending on the host crystals and the process conditions [1]. In BaTiO3, a reduction using CaH2 leads to partial and random substitution of H-for the O2-site, which is compensated by a formal valence change of Ti4+ to Ti3+, imparting an electronic conduction [2] (Fig. 1a). In contrast, a low temperature reduction of SrFeO3 preferentially eliminates O2-at axial sites in the FeO6 octahedra without the H--incorporation to convert to SrFeO2 with a unique planner four-coordinated Fe2+ [3] (Fig. 1b). An intermediate result has been obtained in a layered perovskite, LaSrCoO4, in which H- ions are selectively incorporated in specific O2- sites to form trans-configuration of H-ions [4]. Herein, we focus on the metal hydride-reduction of BaZr1-xYxO3-x/2 (BZY) and BaSn1-xYxO3-x/2 (BSY) and relevant defect chemistry. Both system have the primitive cubic perovskite structure and are popular fast protonic conductor. The latter is related to our expectation that the H-ions are incorporated with a similar manner with the OH- formation via OOX + VO·· + CaH2 ® 2HO· + CaO. BZY and BSY powders were annealed in vacuum-sealed glass tubes containing metal hydride agents at 350-550 °C.

Please click Additional Files below to see the full abstract.

This document is currently not available here.