A.c. and d.c. susceptibility studies were undertaken on Ag-doped Bi1.7Pb0.3Ca2Sr2Cu3 Oy samples to investigate the quality of the materials and the critical current density. X-ray diffraction (XRD) and resistance measurements were also performed to determine the phase of the samples and the influence of Ag addition on Tc(0). XRD results show that the (2223) high-Tc phase is retained and Tc(0) varies between 103 and 107 K. These results suggest that the superconducting properties are not destroyed by Ag addition. The a.c. susceptibility results show two troughs in the χ′ vs. T curves and two peaks in the χ″ vs. T plots. The first peak is smaller, is close to the transition temperature and corresponds to the midpoint of the first trough in the χ-T curve. The second peak appears below 98 K and corresponds to the midpoint of the second trough. The positions of both sets of peaks remain almost the same. The low-temperature peaks are sharper in samples containing silver compared with the pure sample, and the sharpness increases with an increase in silver concentration. Jc was calculated from d.c. susceptibility data using Bean's critical state and plate-like models. Jc was calculated from d.c. susceptibility data using Bean's critical state and plate-like models. Jc increases with silver doping. The increase in sharpness of the low-temperature loss peak with an increase in Ag concentration and critical current density suggests that Ag probably precipitates along the grain boundaries and improves the interconnectivity between the grains.
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