  High-quality polycrystalline SmFeAsO0.75 was synthesized with a
superconducting transition width less than 1 K, and the electronic behavior was
systematically studied by transport and specific heat measurements. An obvious
superconducting jump was witnessed, together with a very small normalized
superconducting jump, which is much smaller than expected by the BCS theory. A
strong temperature dependent Hall coefficient was found and attributed to the
partial gapping of the Fermi surface up to the temperature of 160 K which was
predicted and supported by the emergence of the pseudogap. The charge-carrier
density as well as the effective mass were also obtained and discussed in
detail.
