AC/DC susceptibility of the heavy-fermion superconductor CePt3Si under pressure

We have investigated the pressure dependence of ac and dc susceptibilities (chi(ac) and chi(dc)) of the heavy-fermion superconductor CePt3Si (T-c = 0.75 K) that coexists with antiferromagnetism(T-N = 2.2 K). As hydrostatic pressure is increased, T-c first decreases rapidly, then rather slowly near the critical pressure P-c = 0.6 GPa and shows a stronger decrease again at higher pressures, where P-c is the pressure at which T-N becomes zero. A transition width and a difference in the two transition temperatures defined in the form of structures in the out-of-phase component Of chi(ac) also become small near P-c, indicating that a double transition observed in CePt3Si is caused by some inhomogeneous property in the sample that leads to a spatial variation of local pressure. A sudden increase in the Meissner fraction above P-c suggests the influence of antiferromagnetism on superconductivity.