JOURNAL OF LOW TEMPERATURE PHYSICS, vol.156, pp.22-29, 2009 (SCI-Expanded)
The magnetoresistance of Bi1.7Pb0.3-x Nd (x) Sr2Ca3Cu4O12+y superconductors with x=0.025, 0.050, 0.075 and 0.10 have been measured for different values of the applied magnetic field. Thermally activated flux creep model has been studied in order to calculate the flux pinning energies. The calculated flux pinning energies decrease with the increasing Nd-content and applied magnetic field