The effect of the number of Ag layers on some physical properties of Bi_1.8Pb_0.4Ca_2.2Sr₂Cu₃O_x

Bi_1.8Pb_0.4Ca_2.2Sr₂Cu₃O_x/Ag multilayered samples with 2, 4 and 8 layers are prepared by powder in tube (PIT) method and the effect of multilayering with Ag on the superconducting and the microstructural properties of Bi_1.8Pb_0.4Ca_2.2Sr₂Cu₃O_x is studied. The investigations consist of XRD, SEM, EDS, magnetoresistivity, and I–V measurements. In the magnetoresistivity measurements, magnetic fields up to 0.5 T are applied both parallel and perpendicular to the current flow direction. The superconducting and microstructure properties of the samples are enhanced as the number of Ag layers are increased. The samples are composed of a highly oriented Bi-2223 phase in the regions near the Ag layers. The formation of the dense oriented structure is near the interface between oxide and the Ag layer. T_c and J_c values are enhanced from 107 to 109 K and from 240 to 600 A/cm² by increasing the number of Ag layers, respectively. The results suggest that Ag plays an important role in the improvement of superconducting properties. The possible mechanisms of the enhancement of superconducting properties due to Ag layering are discussed.