Crystal structure, Tc, magnetic properties and Mössbauer spectrum of Fe-doped GdBa2Cu3O7−δ

✍ Scribed by S.T. Lin; C.L. Lin; K.C. Lin; C. Tien; I.M. Jiang

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 492 KB
• Volume: 159
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(89)90368-7

✦ Synopsis

A series of superconductors GdBa2Cu3_xFexO7_, have been prepared to study the effect of the substitution of Fe for Cu on the crystal structure, T c and magnetic properties. For x~ 0.07, the substitution of Fe for Cu increases the lattice parameter a, but decreases the lattice parameter b; for x > 0. l, the crystal structure changes from an orthorhombic to a tegragonal structure. M~issbauer studies reveal that for x=0.05 most of the Fe dopants are at Cu( l ) sites, while for x=0.2 a substantial proportion of Fe dopants might be at Cu (2) sites. Tc decreases with increasing Fe concentration. The rapid drop in Tc for x >-0.1 is attributed to a significant increase in the number of Fe dopants at Cu (2) sites. The magnetic behavior above Tc follows the Curie-Weiss law and the effective average magnetic moment decreases as the Fe concentration is increased.