Determination of Superconducting Parameters of GdBa2Cu3O7−δ Added with Nanosized Ferrite CoFe2O4 from Excess Conductivity Analysis

Abstract

Superconductor samples of the type (CoFe2O4)xGdBa2Cu3O7−δ, 0.0≤x≤0.1 wt.%, were synthesized by the conventional solid-state reaction technique and were characterized using X-ray powder diffraction (XRD) and scanning electron microscope (SEM). XRD analysis indicated that the orthorhombic structure of Gd-123 is not affected by nanosized ferrite CoFe2O4 addition, whereas the volume fraction of Gd-123 increased up to x=0.01 wt.%. Excess conductivity analysis of the investigated samples was analyzed as a function of temperature using the Aslamazov and Larkin (AL) model. It exhibited four different fluctuation regions, namely critical (cr), three-dimensional (3D), two-dimensional (2D), and short-wave (sw). The zero-temperature coherence length along c-axis, effective layer thickness of the two-dimensional system, and inter-layer coupling strength were estimated as functions of nanosized ferrite CoFe2O4 concentration. In addition, the thermodynamics, lower and upper critical magnetic fields, and critical current density were calculated from the Ginzburg number. It was found that the low concentration of nanosized ferrite CoFe2O4 addition up to x=0.01 wt.% improved the physical properties of Gd-123, while for x>0.01 wt.%, these properties were deteriorated.