Electron transport and mobility analysis in La/Sr co-doped CaMnO3–δ

The specific electric conductivity (σ) and Seebeck coefficient (S) are measured in electron-doped manganites Ca1–х–уSrxLaуMnO3–δ (х = 0.4 and y = 0–0.1) in air within temperature (Т) range 350–1220 K. The new approach is suggested to explain the metallic-like increase of S with T based on combination of a small polaron theory with charge disproportionation and spin direction of manganese cations. The temperature-dependent variations of the charge disproportionation equilibrium constant, concentration, and mobility (μ) of charge carriers are derived from the experimental data for S(T) and σ(T). The obtained mobility values vary within 0.1–0.55 cm2 V−1 s−1.