Eur. Phys. J. B 39, 145-148 (2004)
https://doi.org/10.1140/epjb/e2004-00179-8

Sign change of the thermoelectric power in LaCoO₃

Laboratoire CRISMAT, UMR 6508 CNRS ISMRA, 6 boulevard Maréchal Juin, 14050 CAEN Cedex 4, France

Corresponding author: ^a antoine.maignan@ismra.fr

Received: 3 February 2004
Revised: 26 April 2004
Published online: 29 June 2004

Abstract

The substitution of 1%-Ce⁴⁺ for La³⁺ in LaCoO₃ is found to change the sign of the Seebeck coefficient at room temperature. This demonstrates that not only holes but also electrons can be created in LaCoO₃. The result is compatible with the Heikes formula for doping levels close to the “pure” trivalent Co³⁺ state. Nonetheless, the physical properties such as magnetic susceptibility, magnetization, thermal conductivity and resistivity are found to be asymmetric for hole and electron-doped LaCoO₃. Such a different behaviour is ascribed to the very different spin-states of Co⁴⁺ (low-spin, and Co²⁺ (high-spin, .