Papers by Keyword: YBa₂Cu₃O_x

Abstract: Thermal treatment method was employed to produce YBa₂Cu₃O_x superconductor ceramic. The effects of calcination temperature at 850 °C, set A, and 910 °C, set B, for 24 h followed by sintering at 930, 950 and 980 °C, were investigate using X-ray diffraction (XRD), scanning electron microscope (SEM) and four point probe measurement. The orthorhombic structure appears after calcination at 850 and 910 °C beside small amount of impurity phase such as Y₂BaCuO₅ (Y211). The samples exhibited metallic behaviour and the critical temperature, T_C(R=0), increases with increasing sintering temperature. The T_C(R=0) of samples calcined at 910 °C is higher than that of sample calcined at 850 °C. The highest T_C(R=0), 87 K, was found for sample sintered at 980 °C of set B. An increase in grain size and homogeneity was observed as the sintering temperature increases. The set B sample sintered at 980 °C showed compact grains, which could result in the highest T_{c (R=0).}

Abstract: Nano-structured thin films of amorphous YBa2Cu3Ox were prepared by pulsed laser glancing angle deposition. Ambient oxygen pressure and laser fluence have a strong effect on the microstructure of the films. The films exhibit a structural evolution from isolated nanorods, through network of vertical nanocolumns, to nanoparticles fractal with increasing ambient oxygen pressures. Shadowing effect, surface diffusion and flux scattering by ambient gas play main roles in determining the structural evolution.

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