The electrical resistivity, Hall coefficient, and thermopower as functions of temperature are reported for lightly electron-doped ${\mathrm{Ca}}_{1-x}{\mathrm{La}}_x\mathrm{Mn}{\mathrm{O}}_3$ $(0⩽x⩽0.10)$. Unlike the case of hole-doped ferromagnetic manganites, the magnitude and temperature dependence of the Hall mobility $\left({\mu }_H\right)$ for these compounds is found to be inconsistent with small-polaron theory. The transport data are better described by the Feynman polaron theory and imply intermediate coupling $(\alpha \simeq 5.4)$ with a band effective mass $m^{*}\sim 4.3m_0$ and a polaron mass $m_p\sim 10m_0$.

• Received 18 January 2005

DOI:https://doi.org/10.1103/PhysRevB.72.024422