Influência dos parâmetros de síntese no crescimento de grão da eletrocerâmica SmBa2Cu3O7-

Abstract

Polycrystalline samples of SmBa2Cu3O7−𝛿 were prepared by the technique of solid-state reaction with three different procedures. Thus, three samples were prepared from copper and samarium oxides and barium carbonate. After mixing, each sample was compressed in the same way, subjected to a uniaxial pressure of 1 ton and heat treatments whose level of synthesis of the precursor was 960∘C for 24 hours. This procedure was repeated 7 times only for sample A. Then the samples were subjected to another heat treatment at 1060∘C where the samples A and B had a synthesis time of 72 hours, and sample C for 30 minutes. Then the samples were cooled to 520∘C for oxygenation process. These samples were characterized in detail by analysis by X-ray diffraction, ac magnetic susceptibility measurements and scanning electron microscopy. With this last analysis was obtained the average size of the junction between grains for each sample, which were correlated with the ac magnetic susceptibility measurements.