Raman-scattering spectra of YBa2Cu3O6.5 superconductor with ordered oxygen vacancies
Blumberg G. E., Fefer E. M., Fimberg T. A. , Ioon E. R., Lakht A. Kh., Stern R. R. , Rebane L. A.
The ordering of oxygen vacancies has been achieved in a YBa2Cu306 5 system. This ordering leads to the formation of a new crystal phase (the ortho-II phase, Tc = 53 К). The Raman-scattering spectra of the ortho-II phase have been measured at 300 K. These spectra contain the bands at 229, 593, 553, and 630 cm - \ in addition to the Raman spectra of the disordered ortho-I phase. The assignment of the new bands is discussed on the basis of the symmetrized nuclear oscillations which were calculated for the 2aXb X с unit cell.