Small Angle Neutron Scattering Studies of the Vortex Lattice of UPt 3

摘要: Although a paradigm for unconventional superconductivity, the true nature of the superconducting order parameter in UPt 3 is still an open question. We present results from small angle neutron scattering (SANS) studies on the vortex lattice (VL) of UPt 3, for fields both perpendicular and parallel to the crystal c-axis, that have implications for the superconducting order parameter. For perpendicular fields, an unconventional temperature dependence of the VL form factor--and thus penetration depth--is seen, with different dependences in the A and B-phases. This bulk measurement of the penetration depth indicates the presence of nodes in the superconducting gap. For parallel fields, we report the first measurement of a rocking curve from the VL. This is an encouraging result for the viability of using SANS to detect signatures of time reversal symmetry breaking, as the c-axis is taken as the chiral axis in these order …