Fabrication of single crystalline Bi-2212 whiskers from Ga added Bi2Sr2Ca2Cu3Ox composition and their thermal, structural, electrical and magnetic properties

In this study, Bi-2212 superconducting whiskers have been fabricated by annealing a melt quenched Bi2GaSr2Ca2Cu3Ox precursor. Whiskers with 6-15 mu m thickness, 60-95 mu m width and 3-9 mm length were obtained. Crystallization activation energy, E-a, was calculated to be 362 kJ mol(-1) by using Kissinger method. Structural and/or microstructural changes as a result of different heat treatments were investigated with SEM, EDX and XRD analyses. It was found that Ga ions in the starting composition did not diffuse to the structure of whiskers and they enhanced mass transport and accelerated the whisker growth. XRD analysis showed that whiskers consisted of highly c-axis oriented single crystalline Bi2Sr2CaCu2Ox phase. From SEM analysis, it was seen that whiskers had very smooth surface without cracks and dislocations. T-c and T-0 values of the whiskers were found to be 93.1 K and 88.2 K, respectively. Applied magnetic field dependence of the magnetization (M-H) was investigated at 10, 20 and 30 K.J(c) of whiskers were calculated by using Beans' equation and found to be 2.27 x 10(6) A cm(-2), 1.99 x 10(6) A cm(-2) and 0.81 x 10(6) A cm(-2) at 10K, 20K and 30K, respectively. (C) 2012 Elsevier B.V. All rights reserved.