EFG DETERMINATION IN MAGNETIC-FIELD ORIENTED POWDERS OF YBA2((CU1-XFEX)-FE-57)(3)O-7-Y SUPERCONDUCTORS - A TEST OF EXISTING MODELS

YBa2(Cu1-xFex)(3)O-7-y, powder samples with n = 0.02 and 0.03 were uni axially c-aligned in epoxy in a magnetic field of 7.5 T. An X-ray map of the distribution of the orientation of the crystallographic c-axes of the individual crystallites was determined. Fe-57 Mossbauer spectra were recorded at room temperature as a function of the angle between the texture axis and the observation direction. Different sets of EFG parameters were selected from the literature and the fit constraints w ere equally set for all. Using a model of the measured texture functio n and accounting for polarization-dependent blackness effects, a simul taneous fit of the Mossbauer spectra results in minimum chi(2) for the EFG set determined previously from CEMS data on this films.