Interplay between the magnetic fluctuations and superconductivity in the lanthanum cuprates

We report the analysis of the magnetic fluctuations in the superconducing La$_{2-x}$Sr$_x$CuO$_4$ and the related lanthanum cuprates having the different symmetry of the low temperature structure. The NMR and ESR investigations revealed the dynamical coexistence of the superconductivity and the antiferromagnetic correlations in the large part of superconductivity region of the phase diagram. We show that for all compounds, independent on their low temperature symmetry and on their superconducting properties, the enhancement of the spin stiffness near $1/8$ doping takes place.