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

The Raman study has been performed on YBa2Cu3O7-delta (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) over left right arrow -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. (C) 2010 Elsevier B.V. All rights reserved.