Akademik Veri Yönetim Sistemi
SOLID STATE SCIENCES, cilt.13, sa.5, ss.879-886, 2011 (SCI-Expanded)
Single crystalline Bi-based superconducting whiskers have been fabricated from a melt quenched Bi2SbSr2Ca2Cu3Ox. precursor using suitable heat treatment cycles. Whiskers fabricated in this study have 6-15 mu m thickness, 60-95 mu m width and 1-3 mm length. Crystallization activation energy of the material fabricated was calculated to be 609 kJmol(-1) by Kissinger method. Structural and micro-structural changes with the heating treatment cycles were analyzed by XRD and SEM-EDX. It was found that whiskers have pure c-axis oriented single crystalline Bi2Sr2CaCu2Ox (Bi-2212) phase with very smooth surface and without cracks and dislocations. Sb ions did not diffuse directly to the structure of whiskers. But Sb ions added to the system caused to decrease the number of whiskers. Temperature dependence of resistivity was analyzed along both the a- and c-axis. The superconducting transition temperature. To of the whiskers was found to be 93.8 K for the a-axis resistivity and 90.9 K for the c-axis resistivity, respectively. The transport critical current density, integral(trans)(c) was found as 2.6 x 10(5) A/cm(2) at 10 and 1.1 x 10(5) at 70 K. Magnetization hysteresis (M-H) was investigated at three different temperatures (10, 20 and 30 K). Magnetic critical current densities, integral(mag)(c), of whiskers were determined using the Bean's Model. (C) 2011 Elsevier Masson SAS. All rights reserved.