Some doubts about Fe substitution in ReBa2Cu3O7−δ

✍ Scribed by M.W. Dirken; R.C. Thiel; H.H.A. Smit; H.W. Zandbergen

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 360 KB
• Volume: 156
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(88)90827-1

✦ Synopsis

Mbssbauer spectra have been obtained for YBaZCu2.94Fe0.0607-6 and GdBa2Cu2.94Feo.060,-~ at various temperatures down to 0.6 K. The low temperature measurements show four magnetic hyperfine split spectra, two of which are not compatible with Fe'+; combined with IS. data, these spectra are indicative of the Fed' state. A comparisoc is made with the Miissbauer parameters for BaFeO-,. The transition from paramagnetic to magnetically split spectra indicates that much of the "Fe substituted into these high-T, materials is inhomogeneously distributed over the Cu sites. Because of the likelyhood that the high oxidation state of the iron will effect the local oxyge-x surroundings, the usefulness of "Fe substitution into these materials is at best questionable. b