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 [←OCuo→←OCuo→] 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.