The influence of pelletization pressure on normal and superconducting properties of (Bi,Pb):2223 bulk system

Abstract

• We used two pelletization pressures to study the Bi-2223 electrical properties. • The samples have composition consisting of mainly 2223 phase and minor 2212 phase. • It was observed from SEM that some grains are elongated and closely intermixed. • The increase of pelletization pressure reduces porosity and improves grain couplings. • The decrease of weak links resistivity with increasing axial pressure. Bulk samples with nominal composition (Bi 1.6 Pb 0.4 )(Sr 1.8 Ba 0,2 )Ca 2 Cu 3 O y were obtained by the conventional solid-state reaction. Before the sintering process, the powder was compacted at different pelletization pressures. The phase purity and structural parameters of samples were obtained by using XRD measurements. Electrical resistivity vs. temperature measurements have been used to investigate the effect of sintering temperature and uniaxial pressure on the weak link behavior of Bi:2223 polycrystalline samples. The parameters obtained from resistivity data depend on the used pressures to compact the powder, and the value of sintering temperature.