Title
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
Abstract
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.
Recommended Citation
Katsuro Hayashi, Hiroshi Watanabe, Hirofumi Akamatsu, and George Hasegawa, "Different defects formation modes under sevier reducing condition in primitive cubic perovskites, BaZr1-xYxO3-x/2 and BaSn1-xYxO3-x/2" in "Nonstoichiometric Compounds VII", ECI Symposium Series, (2019). https://dc.engconfintl.org/nonstoichiometric_vii/53