A neutron-spectroscopy study of the hydrogen vibrations in hydrogen-doped YBa<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub>
U Knell; H Wipf; H J Lauter; T J Udovic; J J Rush; U Knell; Inst. fur Festkorperphys., Tech. Hochschule Darmstadt, Germany; H Wipf; Inst. fur Festkorperphys., Tech. Hochschule Darmstadt, Germany; H J Lauter; Inst. fur Festkorperphys., Tech. Hochschule Darmstadt, Germany; T J Udovic; Inst. fur Festkorperphys., Tech. Hochschule Darmstadt, Germany; J J Rush; Inst. fur Festkorperphys., Tech. Hochschule Darmstadt, Germany
Журнал:
Journal of Physics: Condensed Matter
Дата:
1993-10-11
Аннотация:
We studied the H vibrations in H-doped YBa<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub>H<sub>y</sub>, (y=0.6) by neutron spectroscopy. Neutron spectra were taken at 10 and 14 K from both orthorhombic (x approximately=6.9) and tetragonal (x approximately=6.3) samples. The spectra exhibit large H-induced intensities in the energy range between 40 and 130 meV. In comparison to orthorhombic samples, the H vibrations in tetragonal samples are shifted to lower energies by approximately 11%. This shift is opposite to the spectral shift of the lattice vibrations between H-free orthorhombic and tetragonal YBa<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub>, frequently attributed to differences in the electron-phonon coupling. Our results show that any such differences in the electron-phonon coupling are not apparent in the H vibrations. The results also support previous suggestions that the H occupies sites in the close neighbourhood of the Cu(l) atomic planes.
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