Unusual interplay between copper-spin and vortex dynamics in slightly overdoped La1.83Sr0.17CuO4

Our inelastic neutron scattering experiments of the spin excitations in the slightly overdoped La1.83Sr0.17CuO4 compound show that, under the application of a magnetic field of 5 tesla, the low-temperature susceptibility undergoes a weight redistribution centered at the spin gap energy. Furthermore, by comparing the temperature dependence of the neutron data with ac susceptibility and magnetization measurements, we conclude that the filling-in of the spin gap tracks the irreversibility/melting temperature rather than Tc2, which indicates an unusual interplay between the magnetic vortices and the spin excitations even in the slightly overdoped regime of high-temperature superconductors.