HYDROGEN IN YBA2CU3OX - A NEUTRON SPECTROSCOPY AND A NUCLEAR-MAGNETIC-RESONANCE STUDY

The high temperature superconductor YBa2Cu3Ox absorbs considerable amo unts of hydrogen if it is kept at elevated temperatures in a hydrogen gas atmosphere. In parallel neutron spectroscopic and nuclear magnetic resonance experiments, we studied the vibrational spectra and the spi n lattice relaxation time of the protons in YBa2Cu3Ox samples that wer e doped with hydrogen due to the absorption of hydrogen gas. Both, the vibrational spectra and the spin lattice relaxation time are a sensit ive probe for the local environment of the protons. We carried out ana logous measurements on samples with a similar proton concentration due to the uptake of water vapour. These experiments demonstrated a total ly different local environment of the protons. This fact is a strong i ndication that the protons absorbed from the hydrogen gas atmosphere d id not react with the oxygen of the sample under formation of molecula r water.