Structural behavior and chemical order of Fe in YBa2(Cu1 − xFex)3O7 + δ

Suppression of Tc in the (Y0.9Ca0.1)Ba2Cu4$minus$xFexO8 system

“…As is now well known, the Mössbauer spectra reported in the literature for the Y123Fe phase consist of three main quadrupole doublets, which have Q of approximately 2.0 mm s −1 , 1.10 mm s −1 and 0.55 mm s −1 . The only doublet that has been associated with the Cu(2) sites is the one whose Q is around 0.55 mm s −1 [14]. At high iron concentrations, besides the presence of quadrupole doublet (A), the quadrupole splittings of doublets B (2.0 mm s −1 ) and C (0.90 mm s −1 ) have values close to those associated with Fe 3+ occupying Cu(1) of the Cu-O single chains of the Y123 structure that result from the destabilization of the (Cu-O) 2 double chains [9].…”

Structure phase transition in FeSr2YCu2O6+δ

“…There were many reports [1][2][3][4][5] on the substitution of Fe for Cu in the Ba 2 YCu 3 O 6+d high-T c superconductor to investigate the behavior of the magnetic Fe elements in the high-T c superconductors. These reports show that the superconducting transition temperature T c decreases with increasing of substituted Fe content.…”

Crystal Structure of Magnetic Superconductor FeSr2YCu2O6+δ

“…There have been a number of reports [1][2][3][4][5] on the substitution of Fe for Cu in Ba 2 YCu 3 O 6þ system, which can be described by stacking of sheets along the c-axis with a sequence of (CuO ) o (BaO) c (CuO 2 ) o (Y) c (CuO 2 ) o (BaO) c according to a descriptive method proposed by Santoro et al, 6) where the subscripts o and c stand for whether the cation on the each slice is at the origin or at the center of the sheet. All these reports show that the superconducting transition temperature, T c , decreases with increasing the content of Fe regardless of the sample preparation conditions.…”