Antiferromagnetic fluctuations in water-intercalated YBa$_2$Cu$_3$O$_{6.8}$

Raman scattering by phononic and electronic excitations, as well as the magnetic susceptibility of water-intercalated YBa$_2$Cu$_3$O$_{6.8}$, has been studied. Direct evidence of the incorporation of OH$^-$-groups into the structure of the crystal has been obtained. The observed changes in the phonon spectrum and the appearance of the spectrum of antiferromagnetic fluctuations with an increased exchange coupling constant imply the localization of carriers and suppression of superconductivity. Change in the resonance behavior of the two-magnon scattering of light indicates the transformation of the electronic structure in crystallites absorbing water.