Search results for "Yba2cu3o7 δ"
showing 2 items of 2 documents
Phonon Softening and Electron-Phonon Interaction in YBa2Cu3O7−δ
1993
We report on the Raman scattering investigation of the 335 cm−1 phonon of Ag (pseudo-B1g) symmetry in thin YBa2Cu3O7−δfilms on various substrates. The experiments yield values for the phonon softening below Tc, which differ from sample to sample. We find a linear relation between the softening and the inverse asymmetry parameter of the phonon Fano-like lineshape, when these parameters, obtained from different samples, are compared with each other. In contrast to this, the onset temperatures for the softening are the same for these samples.
Relation between microstructure and transport properties of epitaxial YBa2Cu3O7-d thin films.
1997
Abstract In order to understand the origin of the high critical current densities observed in thin superconducting films compared to single crystals we measured in several epitaxial YBa 2 Cu 3 O 7−δ thin films the magnetic field and temperature dependence of the superconducting current density j s and the dynamical relaxation rate Q ≡ d ln j s / d ln( d B/ dt ). For all samples we found that (i) the superconducting current density j s is independent of magnetic field up to a certain field B Φ . The value of this field, which is sample dependent, decreases with increasing temperature; (ii) for fields B>B Φ , the superconducting current density falls off as B −1/2 over several decades; (iii) …