  Characteristic normal-state charge transport is found in the oxygen-deficient
iron-arsenides LnFeAsO1-y (Ln: La and Nd) with the highest Tc's among known
Fe-based superconductors. The effect of "doping" in this system is mainly on
the carrier scattering, quite distinct from that in high-Tc cuprates. In the
superconducting regime of the La system with maximum Tc = 28 K, the
low-temperature resistivity is dominated by a T^2 term. On the other hand, in
the Nd system with Tc higher than 40 K, the carriers are subject to stronger
scattering showing T-linear resistivity and small magnetoresistance. Such
strong scattering appears crucial for high-Tc superconductivity in the
iron-based system.
