MARTINEZ, LUIS G.ROSSI, JESUALDO L.ORLANDO, MARCOS T.D.PASSOS, CARLOS A.C.CORREA, HAMILTON P.S.2014-07-152014-07-302014-07-152014-07-302008MARTINEZ, LUIS G.; ROSSI, JESUALDO L.; ORLANDO, MARCOS T.D.; PASSOS, CARLOS A.C.; CORREA, HAMILTON P.S. Study of the crystal structure of the high Tc superconductor Hg1-xRe xBa2Ca2Cu3O8+δ by using EXAFS, XANES and XRD. <b>Materials Research</b>, v. 11, n. 2, p. 131-135, 2008. DOI: <a href="https://dx.doi.org/10.1590/S1516-14392008000200004">10.1590/S1516-14392008000200004</a>. Disponível em: http://repositorio.ipen.br/handle/123456789/4988.1516-1439http://repositorio.ipen.br/handle/123456789/4988Hg based superconducting ceramics present the highest critical temperatures ever reported, particularly the phase 1223 with the highest Tc so far obtained -135 K. However, these compounds are obtained by a complex synthesis route and suffer degradation at ambient atmosphere. This disadvantage may be overcome by doping with an appropriate amount of Re. Samples of nominal composition Hg0.82Re0.18Ba2Ca2Cu3O8+δ having different oxygen contents were studied by X ray absorption and diffraction techniques. Using XANES we determined the Re valence = +7 in an octahedral distorted coordination. We determined the distances of Re-O bonds (1.85 Å and 2.10 Å) by EXAFS. XRD Rietveld fits showed segregation of two superconducting phases with distinct lattice parameters. The main phase is associated with Hg, Re-1223 with higher oxygen content, and the secondary superconducting phase is related to undoped Hg-1223.131-135openAccesshigh-tc superconductorscrystal structuresuperconductivitymulti-element analysisrheniumoxygenoxidationsynthesisx-ray diffractioncrystallographyArtigo de periódico21110.1590/S1516-14392008000200004https://orcid.org/0000-0002-8304-9939https://orcid.org/0000-0001-7707-7821