Polarized Raman spectra of superconducting YBa 2Cu 3O 7 single microcrystals

Abstract

The Raman spectra of superconducting YBa 2Cu 3O 7 ( T c = 93 K) microcrystal have been measured at room temperature using micro Raman technique. Six phonon Raman lines have unambiguously been identified. All of the five Ag symmetry phonons predicted by factor-group analysis are found at 502, 441, 339, 148 and 118 cm −1 and attributed to certain vibrations of the crystal lattice. The phonon at 59 cm −1 has B 2 g ( B 3 g ) symmetry. The two phonons at the lowest frequencies are attributed to the vibrations of Ba.