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

Superconductor samples of the type (CoFe₂O₄) _x GdBa₂Cu₃O_7??? , 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.