Raman analysis of a YBa2Cu3O7-δ thin film with oxygen depletion

The Raman study has been performed on YBa2Cu3Ox=7-δ (YBCO)/MgO thin films. Two modes at 232 and 596 cm-1 are exhibited in a film with continuous oxygen depletion. The modes are related to in-phase stretch [O→-Cu↔-o→] and out-of-phase stretch [ <- O-Cu-o→] along the b-direction, where O(1) and o(1) are full and deficient oxygen, respectively. They are interpreted thoroughly by other publications. Oxidized Cu films show the 630-cm-1 phonon that is consistent with a mode in YBCO. This result allows us to consider the phonon as a defect mode induced from CuO molecules which are nonstoichiometric in YBCO crystals.