X-RAY DIFFRACTION, RA", INFRARED AND MOSSBAUER SPECTRA OF HEAVILY Fe DOPED Bi$rfla@I&d

We report measurements on x-rays diffraction and Raman, infrared and Mdssbauer absorption spectra of Bi2Sr2Cal (Cul -x,Fex)208+6, 0.051x<0.25. X- ray analysis shows that the increment of Fe in the CuOp layers results in the growing of the n=l phase at the expense of the n=2, with possible segregation of Fe at the higher dopant concentration. Mksbauer characterization requires two different confiurations for the Fe in the n=2 phase. Only one doublet is assigned to the Fe at the Cu site for n=l . The resulting spin configuration shows an one mode behavior for the 2-magnon Raman response. These low temperature normal state spectra have resonant behavior that help to put in evidence a second weaker band at higher frequencies, assigned to four spin exchanges. Infrared spectra, in agreement with isomer shifts suggesting the presence of Fe3+, yields ionic features expected for an environment with long range interactions in which oxygen ions play a main role.