Thermogravimetry and neutron thermodiffractometry studies of the H-YBa2Cu3O7 system.

Abstract

The high Tc superconducting oxide YBa2Cu3O7¿x reacts with hydrogen gas. Thermogravimetric, X-ray and neutron scattering experiments allow us to propose a two-step type of hydrogen bonding. Firstly, a few hydrogen atoms fill some oxygen vacancies and may favourably modify the electron state, giving rise to a slight increase in the critical temperature. Secondly, after a prolonged heating period, the collapse of the YBa2Cu3O7¿x type framework and of superconductivity were observed, and a new, highly hydrogenated material appeared