Hydrogen vibrations in HxYBa2Cu3O7 superconducting ceramics

Abstract

The inelastic neutron scattering (INS) and neutron diffraction (ND) spectra from the HxYBa2Cu3O7 superconducting ceramics (x= 0.05, 0.20, 0.60) are investigated at 290, 80 and 10 K. Vibrational spectra of hydrogen atoms show three wide bands at about 10, 28 and 85 meV. Intensities of them are proportional to the hydrogen concentration. From the temperature behaviour of the INS spectra and from the X-ray and ND results for different hydrogen concentrations we can conclude that this bands correspond to an amorphous, not superconducting precipitations which are formed during hydration of Y-123 superconducting ceramics. From the concentration dependence of the INS spectra we can conclude that the solubility of hydrogen in Y-123 superconducting phase is in order of few percent. It seems that H atoms in solid solution are located in the octahedral position formed by four Y and two Cu(2) atoms.