Crystal structure and thermoelectric properties of Sr-Mo substituted CaMnO3: a combined experimental and computational study.A combination of experimental and computational techniques has been employed to study doping effects in perovskite CaMnO3.  Atomically resolved imaging and analysis showed a random distribution of Sr in the A-site of the perovskite structure and revealed a boundary structure of 90° rotational twin boundaries across {101}orthorhombic; the latter are predominant phonon scattering sources to lower the thermal conductivity as suggested by molecular dynamics calculations.  The effect of doping on the thermoelectric properties was evaluated.  The major impact of Sr on thermoelectric behaviour is the reduction of the thermal conductivity as shown experimentally and by modelling.  Strontium containing ceramics showed thermoelectric figure of merit (ZT) values higher than 0.1 at temperatures above 850 K. Ca0.7Sr0.3Mn0.96Mo0.04O3 ceramics exhibit enhanced properties with S1000K = -180 μV K-1, ρ1000K = 5 × 10-5 Ωm, k1000K = 1.8 W m-1 K-1 and ZT ≈ 0.11 at 1000 K.
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