RAMAN STUDIES ON BACUO2, BA2CUO3 AND BA2CU3O5.9

The Raman spectra of several as-synthesized barium cuprates, BaCuO2, Ba2CuO3 and Ba2Cu3O5.9, and annealed Ba2Cu3O5.9 were studied in this work. Characteristic Raman bands were found at 633, 563 and 592 cm-1, respectively. They were polarized. These three strong bands can be used to identify these cuprates. The 563 cm-1 band of Ba2CuO3 could be assigned to the vibrational mode of the apical oxygen along the c-axis. The 633 cm-1 band of Ba2Cu3O5.9 could be assigned to the vibration of O(VI). Other Raman bands were not assigned due to the complicated structures. The Raman spectra of annealed Ba2Cu3O5.9 under different conditions indicated that Ba2Cu3O5.9 decomposed to BaCuO2; this was initiated by a high temperature and completed over a long-period treatment.