Akademik Veri Yönetim Sistemi
CHINESE JOURNAL OF PHYSICS, cilt.43, sa.2, ss.372-383, 2005 (SCI-Expanded)
Bi-Pb-Gd-Sr-Ca-Cu-O bulk samples with nominal composition Bi1.7Pb0.29Gd0.01Sr2Ca3Cu4O12+y (2234) were prepared by the melt-quenching method. The effects of different annealing times on the structure have been investigated by electrical resistance, scanning electron micrographs, and magnetization measurements. The magnetization measurements have been carried out as a function of the magnetic field up to 5 kOe for field temperatures below the zero resistance temperatures of the annealed samples. It has been found that the high-T-c superconducting phase, (2223), can be formed by annealing at 840 degrees C for 120 h. The decrease in magnitude of the initial susceptibility dM/dH and the fast decrease of hysteresis loops, related to the superconducting volume with increasing temperature, seem to imply an existence of flux pinning centers in our samples.