  We report on novel superconducting characteristics of the heavy fermion (HF)
superconductor CePt3Si without inversion symmetry through 195Pt-NMR study on a
single crystal with T_c= 0.46 K that is lower than T_c= 0.75 K for
polycrystals. We show that the intrinsic superconducting characteristics
inherent to CePt3Si can be understood in terms of the unconventional
strong-coupling state with a line-node gap below T_c= 0.46 K. The mystery about
the sample dependence of T_c is explained by the fact that more or less
polycrystals and single crystals inevitably contain some disordered domains,
which exhibit a conventional BCS s-wave superconductivity (SC) below 0.8 K. In
contrast, the Neel temperature T_N= 2.2 K is present regardless of the quality
of samples, revealing that the Fermi surface responsible for SC differ from
that for the antiferromagnetic order. These unusual characteristics of CePt3Si
can be also described by a multiband model; in the homogeneous domains, the
coherent HF bands are responsible for the unconventional SC, whereas in the
disordered domains the conduction bands existing commonly in LaPt3Si may be
responsible for the conventional s-wave SC. We remark that some impurity
scatterings in the disordered domains break up the 4f-electrons-derived
coherent bands but not others. In this context, the small peak in 1/T_1 just
below T_c reported in the previous paper (Yogi et al, 2004) is not due to a
two-component order parameter composed of spin-singlet and spin-triplet Cooper
pairing states, but due to the contamination of the disorder domains which are
in the s-wave SC state.
