Anharmonicity of high-frequency O vibrations in YBa 2 Cu 3 O 7-? , TlBa 2 CaCu 2 O 7-? and Tl 2 Ba 2 CaCu 2 O 8-? deduced from high-temperature Raman spectra
- 1 May 1992
- journal article
- research article
- Published by Taylor & Francis in Ferroelectrics
- Vol. 130 (1), 107-116
- https://doi.org/10.1080/00150199208019537
Abstract
High temperature Raman spectra on single crystals of YBa2Cu3O7-δ, TlBa2CaCu2O7-δ and Tl2Ba2CaCu2O8-δ show significant softening and broadening of apical oxygen vibrational modes above 300 K. This behaviour appears to be a common in superconducting oxides with a pyramidal O structure surrounding planar Cu ions. Although this high-temperature behaviour is characteristic of anharmonic modes, we find that a simple double well static anharmonic potential cannot fully explain these observations.Keywords
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