Metal-semiconductor transition in the defective perovskite LaCu1-xNiO2.5+δ
Bazuev G. V. , Krasil'nikov V. N. , Kirsanov N. A., Lukin N. V.
Abrupt and reversible changes in the oxygen content and the electrical conductivity have been detected at ~ 500 °C in the anion-deficient perovskite LaCui^Ni^C^.s+s, which was synthesized as part of this study. These changes accompany a transition from a metallic to a semiconducting behavior. The changes were found by x-ray diffraction, differential thermal analysis, thermogravimetry, and measurements of the electrical conductivity. The anomalies observed here are shown to be accompanied by a structural phase transition and are linked with a sharp change in the Cu3+/Cu2+ cation ratio in the lowand high-temperature phases.