Thermoelectric properties of n-type Ca1−xBixMn1−ySiyO3−δ (x = y = 0.00, 0.02, 0.03, 0.04, and 0.05) system

Polycrystalline samples of Ca1−xBixMn1−ySiyO3−δ (x = y = 0.00, 0.02, 0.03, 0.04, and 0.05) are prepared by conventional solid state reactions. Thermoelectric properties are measured at 300–700 K. All the samples are single phase with an orthorhombic structure. Thermopower of all the samples is negative, indicating that predominant carriers are electrons over the entire temperature range. Among the samples, Ca0.98Bi0.02Mn0.98Si0.02O3−δ has the highest dimensionless figure of merit ZT = 0.02. This value represents an improvement of about 162% with respect to the parent compound of CaMnO3−δ at 300 K.

► Codoping of Bi and Si has remarkable effects on transport behavior of CaMnO3−δ.
► Both resistivity and thermal conductivity can be achieved in Ca1−xBixMn1−ySiyO3−δ.
► Ca0.98Bi0.02Mn0.98Si0.02O3−δ has the highest ZT of 0.021 at 300 K.
► About 162.5% improvement as compared to undoped CaMnO3−δ at room temperature.