RAMAN-SCATTERING FROM SINGLE-CRYSTAL YBA2CU3O7-DELTA IN A MAGNETIC-FIELD

A magneto-Raman study of a YBa2Cu3O7-delta single crystal (T-c=92 K) w as carried out at a resolution of 2 cm(-1) over the temperature range 5-125 K. At temperatures below T-c we observed a slight narrowing of t he 340 cm(-1) Raman mode in a magnetic field of 5.15 T directed parall el to the c-axis of the crystal. The observed magneto-temperature depe ndences of the Raman continuum intensity measured in the low-frequency region, at ca. 40 cm(-1), indicate contributions of electronic excita tions arising from a pair-breaking process. Within the experimental un certainty, the Raman intensity of the high-frequency continuum was obs erved to be independent of the magnetic field strength.