Reply to ``Comment on `Paramagnetic Meissner effect in Nb' ''

Abstract

Rice and Sigrist (RS) have proposed a d-wave mechanism to explain the paramagnetic Meissner effect (PME) observed in some inhomogeneous samples of high-${\mathrm{T}}_{\mathrm{c}}$ superconductors. However, the observation of a PME in some inhomogeneous samples of Nb (an s-wave superconductor) demonstrates that a d-wave pairing mechanism is not needed to produce the effect. Moreover, the remarkable similarity between the PME observed in these Nb and in the high-${\mathrm{T}}_{\mathrm{c}}$ samples argues that the same mechanism is operable in both types of superconductors. In this Reply, new measurements on ${\mathrm{La}}_{2}$${\mathrm{CuO}}_{4+\mathrm{\ensuremath{\delta}}}$ and on irradiated Nb are discussed, which strongly support the notion that the PME is most likely associated with layered ${\mathrm{T}}_{\mathrm{c}}$ inhomogeneities. Further experiments to test this notion are proposed. We also discuss critically the three experiments proposed by RS to distinguish between two PME mechanisms unrelated to layered ${\mathrm{T}}_{\mathrm{c}}$ inhomogeneities.