  Single-phase films of the full Heusler compound Fe2TiSi have been prepared by
magnetron sputtering. The compound is found to be a semiconductor with a gap of
0.4eV. The electrical resistivity has a logarithmic temperature dependence up
to room temperature due to Kondo scattering of a dilute free electron gas off
superparamagnetic impurities. The origin of the electron gas is extrinsic due
to disorder or off-stoichiometry. Density functional theory calculations of the
electronic structure are in excellent agreement with electron energy loss,
optical, and x-ray absorption experiments. Fe2TiSi may find applications as a
thermoelectric material.
