Thermoelectric power factor of RuSr₂GdCu₂O₈

Abstract

The influence of thermal treatment between 1273 and 1333 K in an oxygen atmosphere on the perovskite system RuSr₂GdCu₂O₈ was studied by X-ray diffraction (XRD), scanning electron microscopy, electrical resistivity and Seebeck coefficient measurements. The XRD patterns revealed that the phase purity depends on the sintering process. The samples were found to exhibit very small crystallite sizes in the nanometer range. The electrical resistivity was found to be strongly correlated with the heat treatment. The temperature dependence of electrical resistivity for one sample revealed semiconducting behavior, whereas the others exhibit metallic behavior. All the investigated samples exhibit a positive thermoelectric power, indicating the predominance of positive charge carriers. It was found that the power factor reaches a maximum value of 0.4 × 10⁻⁴ W m⁻¹ K⁻² at 300 K.

Keywords:

• thermoelectric power
• RuSr₂GdCu₂O₈ perovskite
• sintering
• resistivity
• Seebeck coefficient