Critical fluctuation of the order parameter in type-ii superconductors.

Sonochemical synthesis and physical properties of Co0.3Ni0.5Mn0.2EuxFe2-xO4 nano-spinel ferrites.

In this work, the effect of SnO2 nano-particles (40 nm) addition to the physical properties of Bi1.6Pb0.4Sr2Ca2Cu3O10+δ superconducting phase was studied. (Bi, Pb)-2223 superconductor phase added by SnO2 nano-particles was prepared by a conventional solid-state reaction technique. The SnO2 nano-particles concentrations x varied from 0.0 to 2.0 wt% of the sample’s total mass. The prepared samples were investigated by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and electron dispersive spectroscopy (EDS) for analyzing phase formation and microstructure. Also, the electrical resistivity and transport critical current density, for investigated samples, were measured by standard dc four-probe method. Phase examination by XRD indicated that SnO2 nano-particles enhanced the (Bi, Pb)-2223 phase formation up to x=0.4 wt%. On the other hand, the high concentrations of SnO2 nano-particles retarded the phase formation. Granular investigation, from scanning electron microscope, showed that both number and size of voids decreased as x increased from 0.0 to 0.4 wt%. The superconducting transition temperature and transport critical current density were found to have optimal values at x=0.4 wt%. The enhancement rates in Tc and Jc were 12 and 58%, respectively, which had a maximum enhancement in both Jc and Tc for all investigated nano-particles.

Improving the Physical Properties of (Bi, Pb)-2223 Phase by SnO2 Nano-particles Addition

BaTiO3/(WO3)x ceramics (where x = 0, 0.5, 1, 2 and 5 wt%) were prepared by solid state reaction. X-ray powder diffraction, scanning electron microscope, Fourier transform-infrared spectroscopy and ultraviolet–visible diffuse reflectance spectrophotometry were used to investigate the structure, morphology and optical properties, respectively. The electrical and dielectric properties were also performed for different synthesized ceramics. A pure phase was obtained for x = 0.5 wt% ceramic, nevertheless a secondary phase was detected for x ≥ 1 wt% ceramics. The grains size increases for x = 0.5 wt% ceramic and then reduces abruptly with further increasing WO3 content. The increase of grains size and the absence of impurities were all efficient to enhance the dielectric properties. A suitable WO3 content leads to obtain ceramics having high dielectric constant and low tangent loss, which is encouraging for radio frequencies and microwaves applications.

Study of tungsten oxide effect on the performance of BaTiO 3 ceramics

Structural, magnetic, optical properties and cation distribution of nanosized Co0.7Zn0.3TmxFe2−xO4 (0.0 ≤ x ≤ 0.04) spinel ferrites synthesized by ultrasonic irradiation

SiO2 nanoparticles addition effect on microstructure and pinning properties in YBa2Cu3Oy

Influence of WO3 nanowires on structural, morphological and flux pinning ability of YBa2Cu3Oy superconductor

AC susceptibility investigation of YBCO superconductor added by carbon nanotubes

Higher intra-granular and inter-granular performances of YBCO superconductor with TiO2 nano-sized particles addition

We report electrical conductivity fluctuation analyses on YBa2Cu3O7−d
 (noted Y-123) and Y3Ba5Cu8O18±x
 (noted Y-358) polycrystalline samples added with nano-sized ferrite cobalt (CoFe2O4) particles. Phases and microstructure have been systematically investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results reveal that the lattice parameters change for both Y-123 and Y-358 phases. SEM observations show that the grain size is reduced with increasing the content of CoFe2O4 in the yttrium-based superconductor (YBCO) matrix The temperature dependence of electrical resistivity ρ(T) has been measured and the effect of addition of magnetic CoFe2O4 in the paraconductivity region has been reported. The thermodynamic fluctuation is obtained by analyzing the excess of conductivity on the basis of the Aslamazov–Larkin theory. The coherence length, the effective layer thickness, critical magnetic fields, and critical current density are estimated. Superconducting parameters are affected by the nanoparticle addition, and results are discussed in relevance to the structural and microstructure differences between Y-123 and Y-358.

F. Ben Azzouz

Papers

SiO2 nanoparticles addition effect on microstructure and pinning properties in YBa2Cu3Oy

Influence of WO3 nanowires on structural, morphological and flux pinning ability of YBa2Cu3Oy superconductor

AC susceptibility investigation of YBCO superconductor added by carbon nanotubes

Higher intra-granular and inter-granular performances of YBCO superconductor with TiO2 nano-sized particles addition

Excess Conductivity Study in Nano-CoFe 2 O 4 -Added YBa 2 Cu 3 O 7−d and Y 3 Ba 5 Cu 8 O 18±x Superconductors