  The F doped LaFeAsO, a recently discovered superconductor with the high Tc of
26 K, has been studied by the resistivity, magnetic susceptibility, and heat
capacity measurements in the F doping range from 0 to 0.14 (x in LaFeAsO1-xFx).
In the low temperature region, a T3lnT term in the heat capacity and a T2 term
in the magnetic susceptibility, which are derived from the spin fluctuation,
are observed. The nearly ferromagnetic nature evidenced by a large Wilson ratio
(6.5 for x = 0, and 11.2 for x = 0.025) suggests that the superconductivity in
the LaFeAsO system is mediated by ferromagnetic spin fluctuation.
