Neutron Scattering Study of Single Crystals of the High Tc Superconductor Nd-LSCO at High Doping*

The La-214 family of cuprate superconductors is the original family of high temperature superconductors to be discovered. One branch of this family La(1.6-x)Nd(0.4)Sr(x)CuO4 (Nd-LSCO-x) has been of great interest as it displays the full complexity of the canonical hole-doped high TC phase diagram, but also displays well defined static charge and spin stripe order over a range of concentrations, optimized near x = 0.125.

We conducted neutron scattering experiments on two single crystal samples(x=0.19 and 0.24) using the SEQOIA chopper spectrometer at Spallation Neutron Source of Oak Ridge National Laboratory. We observed incommensurate elastic magnetic scattering at [1/2,1/2,L] positions in both x=0.19 and 0.24 samples at 5K. We also observed low energy spin gap behavior in the x=0.19 sample and 0.24 samples at 5K. As x=0.19 sample is optimally doped and x=0.24 sample at the end of the superconducting dome, our observation appear to nicely demonstrate the coupling between the low energy spin gap and superconductivity in this system.