Meissner effect of heavy-fermion superconductor CePt3Si under pressure

We have investigated the pressure dependence of dc susceptibility chi(dc) of heavy-fermion superconductor CePt3Si for a single crystal and a poly-crystal that show a similar specific heat anomaly at T-c similar to 0.4 K. When coexisting antiferromagnetism disappears at pressures above P-c similar to 0.6 GPa, the Meissner fraction of the single crystal becomes twice or third times as large as that below P-c depending on the magnetic field direction. The poly-crystal, on the other hand, has not shown such an anomaly, possibly because the distribution of local pressure that seems wider than that in the single crystal causes the remains of antiferromagnetic phase even above P-c. (C) 2010 Elsevier B.V. All rights reserved.