Ce-substitution effects in GdBaCo2O5+δ

Resistivity, thermopower, magnetoresistance and magnetic susceptibility investigations of Ce-substituted GdBaCo2O5+δ have been carried out in the temperature range 4.2–300 K. Ce substitution affects the magnetism of the parent compound, decreasing its ferromagnetic and anti-ferromagnetic transition temperatures T C and T N respectively. Thermopower measurements carried out in the temperature range 77–300 K indicate an increase with Ce substitution which remains positive. The magnetoresistance observed in the anti-ferromagnetic region seems to increase with Ce substitution.