Oxidation Phenomena in Semiconducting BaTiO_3

概要

論文の詳細を見る
The effects of sintering ambient and cooling procedure on the electrical resistivity of Gd-doped polycrystalline BaTiO_3 have been investigated. Effects of thermal annealing in air on the resistivity-temperature characteristic have been also studied, of Gd-doped specimens as well as reduced BaTiO_3 both in polycrystalline and single crystal forms. The specimens sintered in nitrogen or those sintered and followed by quenching in air have been found to be semiconducting in a wide range of Gd content (0.2〜1.0atomic%). The high resistivity of highly doped specimens, obtained by the usual sintering process, results from the oxidation during cooling in air. The resistivity anomaly at the Curie point of some reduced single crystals is shown to be surface effect. The PTC anomaly of resistivity in polycrystalline materials may be due to oxidized grain boundary. The oxygen partial pressure during cooling is more effective for the PTC anomaly than that during sintering.
社団法人日本物理学会の論文
1965-04-05