We have accomplished Raman scattering measurements on a polycrystalline sample of YBCO in the temperature range 25-600 degrees C and in oxygen atmosphere. In the spectra at high temperature, we observe, new vibrational structures at 360, 585, and 605 cm(-1). The usual Raman modes at 335, 440, and 500 cm(-1) showed a trend to broaden and flatten with increasing temperature. We attribute the peaks observed at high temperature to IR-active vibrational modes which become Raman-active as a result of temperature induced disorder in the YBCO unit cell. In this perspective, we discuss how the migration of oxygen atoms might account for the observed phenomena.
HIGH-TEMPERATURE STUDY OF THE RAMAN-ACTIVE PHONON MODES OF YBA2CU3O7-DELTA
ULIVI L;
1995
Abstract
We have accomplished Raman scattering measurements on a polycrystalline sample of YBCO in the temperature range 25-600 degrees C and in oxygen atmosphere. In the spectra at high temperature, we observe, new vibrational structures at 360, 585, and 605 cm(-1). The usual Raman modes at 335, 440, and 500 cm(-1) showed a trend to broaden and flatten with increasing temperature. We attribute the peaks observed at high temperature to IR-active vibrational modes which become Raman-active as a result of temperature induced disorder in the YBCO unit cell. In this perspective, we discuss how the migration of oxygen atoms might account for the observed phenomena.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
