Mössbauer studies of the high-TcsuperconductorYBa2(Cu1−xFex57)3O7−δ(x=0.033)

Abstract

The high-$T_c$ superconductor $\mathrm{Y}{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ doped with 3.3 at.% ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ has been investigated by Mössbauer spectroscopy. Measurements on samples prepared under various heat treatments show that Fe substitutes exclusively the Cu(1) sites with Mössbauer signals corresponding to tetragonal and orthorhombic local symmetry. The relative abundance of these signals allows the determination of the oxygen-deficiency parameter. Mössbauer measurements at low temperatures reveal magnetic hyperfine interactions which are tentatively attributed to low-dimensional magnetic ordering. Deoxygenation of the $\mathrm{Y}{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ phase results in the formation of the ${\mathrm{Y}}_2$BaCu${\mathrm{O}}_5$ phase (the green phase) in a reversible way. The Mössbauer properties of the ${}_{}{}^{57}{}_{}{}^{}\mathrm{F}\mathrm{e}-\mathrm{d}\mathrm{o}\mathrm{p}\mathrm{e}\mathrm{d}$ phase are reported.