PARAMAGNETIC MEISSNER EFFECT IN NB - REPLY

Rice and Sigrist (RS) have proposed a d-wave mechanism to explain the paramagnetic Meissner effect (PME) observed in some inhomogeneous samp les of high-T-c superconductors. However, the observation of a PME in some inhomogeneous samples of Nb (an s-wave superconductor) demonstrat es that a d-wave pairing mechanism is not needed to produce the effect . Moreover, the remarkable similarity between the PME observed in thes e Nb and in the high-T-c samples argues that the same mechanism is ope rable in both types of superconductors. In this Reply, new measurement s on La(2)CuOQ(4+delta) and on irradiated Nb are discussed, which stro ngly support the notion that the PME is most likely associated with la yered T-c inhomogeneities. Further experiments to test this notion are proposed. We also discuss critically the three experiments proposed b y RS to distinguish between two PME mechanisms unrelated to layered T- c inhomogeneities.