Iron substitution effects and Mössbauer spectroscopy in Bi−Sr−Ca−Cu ceramic oxides

Mössbauer spectroscopy spectra of the ceramic Bi₂Sr₂Ca(Cu_1-x Fe _x )₂O_8+y forx=0, 0.005, 0.02 and 0.05 shows two doublets, that can be assigned to two different environments for the substituting ion. One of the sites is identified as a single Fe ion replacing a Cu ion in the CuO plane. The other site is associated with the dopant in an interstitial position in the plane, in slightly different environments. This last configuration, which increases with increasingx, is related with adverse effects upon the conductive properties of these materials.