P-type thermoelectric properties of sintered (NiyCo1-y)xFe3-xO4 with spinel structure

Abstract

P-type thermoelectric materials based on magnetite have been obtained by cobalt substitution (Co_xFe_3-x-xO₄ ). For x ges 1.1, Seebeck coefficient (S) was positive and showed a maximum at a temperature which shifted toward high temperature. For x les 1.0, S was negative, and for x ap 1.0, S changes its sign from positive to negative with increasing temperature. The Co content of Co_1.5Fe_1.5-xO₄ yielded a lowest electrical resistivity of 40 mOmegacm at 973K. Effects of Ni and Co co-doping were also discussed