Weak Field Magnetic Susceptibility Fluctuations Above the Superconducting Transition YBa2Cu3−xFexO7−δ(0.05 ≤ x ≤ 0.12)

This paper reports the production of YBa2Cu3−xFexO7−δ (0.05 ≤ x ≤ 0.12) superconducting system by using the standard solid-state reaction technique. A Rietveld refinement of the experimental X-ray diffraction patterns allows the determi- nation of the lattice parameters and the phase composition of the studied system; the mean present phase shown is an orthorhombic phase Pmmm. Magnetic and transport properties are typical for superconducting samples. In this paper, magnetic suscep- tibility fluctuations are studied in the limit of weak magnetic fields. For each of the samples, the best fit of the experimental data of �χ /T, in the limit of weak mag-