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 email@example.com
Revised: 26 April 2004
Published online: 29 June 2004
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, .
PACS: 72.15.Jf – Thermoelectric and thermomagnetic effects / 75.30.Et – Exchange and superexchange interactions / 71.38.-k – Polarons and electron-phonon interactions
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004