Magnetic properties of Sm-doped Bi-2223 superconductor studied by low field local Hall generator ac susceptibility

We studied the grain boundary properties of Sm doped Bi(Pb)SrCaCuO using the Hall generator ac susceptibility (chi = chi' + i chi"). Hall generator is a convenient tool to investigate the shielding effect of superconductors under extremely low magnetic fields. Using a Hall generator system, we have investigated diamagnetic shielding behavior of Bi1.6Pb0.4Sr2Ca2-xSmxCu3Oy samples with x = 0.0, 0.0005, 0.001, 0.005, 0.01 and 0.1. The susceptibility measurements were carried out for ac field amplitudes of 47, 94, 141, 188 and 235 A/m with the frequency of 20 Hz. The critical temperatures were estimated from the temperature dependence of the ac susceptibility curves. We have also employed X-ray diffraction, energy dispersive X-ray fluorescent and scanning electron microscopy techniques to investigate the effect of Sm doping. (c) 2007 Elsevier B.V. All rights reserved.