Abstract
Superconducting samples of type (CoFe2O4)(x) GdBa2Cu3O7-delta, 0.0 <= x <= 0.1 wt.%, have been prepared by the conventional solid-state reaction technique and characterized using X-ray powder diffraction (XRD) and the scanning electron microscope (SEM). XRD analysis indicates that the orthorhombic structure of Gd-123 is not affected by the nanosized ferrite CoFe2O4 addition, whereas the volume fraction of Gd-123 increases with x up to 0.01 wt.%. Nano-sized ferrite CoFe2O4 has been prepared by Co-precipitation method with grain size about 8 nm. The temperature dependence of electrical resistivity has been measured in zero and 0.44 T magnetic fields. Magneto-conductivity data has been analyzed in terms of Aslamazov-Larkin (AL) and Maki-Thompson (MT) models for layered superconductors, considering the orbital contribution. The superconducting parameters such as the coherence lengths along ab plane xi(ab)(0) and along c-direction xi(c)(0) at 0 K, anisotropic parameter Gamma and phase breaking time tau(phi) at 100 K have been determined as a function of nanosized ferrite CoFe2O4 contents. It is found that the low nanosized CoFe2O4 addition contents up to x = 0.01 wt.% improves the physical properties of Gd-123, while for x > 0.01 wt.% these properties are deteriorated.