Abstract

The results of electrical conductivity and thermopower measurements are presented for selected (La,Ca)(Cr,Co)O3 compositions. The La1 - xCaxCrO3 compounds are typical p-type small polaron conductors. The La1 - xCaxCrO3 compounds are found to be small polaron conductors at room temperature for x ≤ 0.20 with a higher electrical conductivity than the corresponding chromite's. The electrical conductivity at room temperature is lower for Co-rich compositions than for Cr-rich compositions for compositions containing 10 mol% and 20 mol% Ca. This fact is attributed to the trapping of p-type small polarons at energetically lower Cr sites, resulting in a broad room temperature conductivity minimum. Above room temperature, the electrical conductivity increases with increasing Co content for all compositions. The thermopower for these compounds is interpreted using the Verwey electronic compensation mechanism including thermally activated disproportionation among Co ions. © 1995.

Department(s)

Materials Science and Engineering

Second Department

Physics

Comments

U.S. Department of Energy, Grant None

Keywords and Phrases

Cobaltites; Disproportionation; Electrical conductivity; Seebeck coefficient; Trapping

International Standard Serial Number (ISSN)

0167-2738

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Elsevier, All rights reserved.

Publication Date

01 Jan 1995

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