Bi 2 Sr 2 Ca 2 Cu 3 O x (Bi-2223) were prepared using a solid state reaction method at different sintering times and temperatures. Structural phase identifications have been done using X-Ray analysis and refinement by Reitveld method which proves the coexistence of Bi-2223 and Bi-2212 phases. The critical transition temperature T c and critical current density J c values were measured using superconducting quantum interference device magnetometer (SQUID) and by the magneto-optics technique. A remarkable rapid decrease to the diamagnetic signal in the magnetization versus temperature M(T) at 110 K and J c around 1.2 Â 10 7 A/m 2 at 5 K are confirmed for the Bi-2223 compound.
Nanocomposites based on poly (vinyl alcohol) (PVA) filled with different types of nanometal oxides named MgO, Al 2 O 3 , and CuO were attained from an aqueous solution of PVA. PVA/nanometal oxide films were achieved by the solution casting procedure. The prepared nanocomposites were subjected to a gamma radiation dose at 50 kGy to study the impact of ionizing radiation on the various properties of the prepared samples. In this context, this work was mainly concerned with the differences in the behavior of various metal oxides, as well as the effect of ionizing radiation on the tensile strength (TS), elongation at break (E%), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction, and optical characteristics of the fabricated specimens. Furthermore, Fourier transform infrared (FTIR), SEM, and thermodynamic factors (E a , ΔH, ΔG, and ΔS) were considered. FTIR and the suggested reaction mechanism supported that the hydroxyl groups of PVA have a really strong affinity to form charge-transfer complexes with different nanometal oxides done chelation. In general, the interference of 0.1% of all studied nanometal oxides improved TS, thermal stability, melting temperature, and optical properties of PVA, whereas PVA/0.1 CuO was the best. Moreover, gamma radiation exposure enhanced the different properties of native PVA and displayed anisotropic behavior toward its nanocomposites.
a b s t r a c tCd 1Àx Mn x Te (x ¼ 0.1, 0.2 and 0.3) have been studies. Structural characterization was carried out by X-ray diffraction. The Rietveld program reveals the formation of nano disordered structure. The lattice parameters were found to decrease by the increasing of Mn content.The dc and Ac conductivities of the prepared semimagnetic semiconductor, were measured in a wide range of temperature and frequency. The obtained data reveal that s Ac (u) obey the relation, s Ac (u) ¼ Au S . The Ac conductivity shows frequency dependent and nearly temperature independent character. The correlated barrier hopping conduction mechanism is applied and single electron hopping between D þ center (Mn þ ) and D 0 (chalcogen atom) is assumed to take place. The magnetic susceptibility was investigated in the temperature range of (170e300) K revealing the paramagnetic behavior described by the CurieeWeiss low.
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