Polycrystalline samples of Ca3-x Dy x Co 4O9+δ (x = 0.00, 0.02, 0.05, and 0.10) have been prepared by conventional solid-state synthesis. The x-ray diffraction (XRD) results revealed that all the samples are single phase. The thermoelectric properties were measured at 25 K to 300 K. The thermopower of all the samples was positive, indicating that the predominant carriers are holes over the entire temperature range. The electrical resistivity of all the samples exhibited the nonmetal-to-metal transition at below 75 K. The electrical resistivity decreased and the thermopower increased with increasing Dy3+ content. Among all the samples, Ca2.9Dy0.10Co4O 9+δ had the highest dimensionless figure of merit of 0.044 at 300 K.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry