μSR study of CeRhIn5 under applied pressure

At ambient pressure CeRhIn5 is an incommensurate antiferromagnet with Neel temperature T-N = 3.8 K. The application of pressure reduces T-N and yields (1) a state in which AFM coexists with superconductivity, and then (2) a superconducting state in the absence of AFM. We report transverse-field muon spin relaxation (mu SR) measurements at pressures 2.07 and 2.26 GPa in the pure superconducting state of single-crystalline CeRhIn5, which has a tetragonal structure. mu SR is sensitive to the local field distribution produced by the vortex lattice in a mixed superconducting state, allowing a measurement of the magnetic field penetration depth lambda(T). We measured lambda(ab)(T) for applied field along the c-axis as a function of temperature T, and find lambda(ab)(0) = 372(5) nm and 338(6) nm for P = 2.07 GPa and 2.26 GPa, respectively. The temperature dependence of the superfluid density rho(s)(T) proportional to lambda(-2)(T) was found to be rho(s)(T) proportional to T-n, with n = 1.9(2).