Relationship between characteristic length and average grain size in nanosize MgO added Bi-2212 superconductor ceramics

• Main Authors: Hamid N.A., Asbullah M.S.N., Yahya S.Y.S., Hashim A.
• Other Authors: 6604077116
• Format: Conference paper
• Published: 2023
• Subjects: Bi-2212 phase superconductor; characteristic length; flux pinning centers; grain size; transport critical current density

In the present work, Bi2Sr2CaCu2O 8 (Bi-2212)/MgO compound was prepared using the conventional solid-state reaction method. The powder of nanosize MgO particles was added to Bi-2212 superconductor with weight percentage of 3%, 5%, and 8%, respectively. The compound was sintered for 48 hours at 855deg;C in air. Besides the existence of a small amount of impurity phases, all the samples showed the Bi-2212 phase as the dominant phase. The temperature dependence of transport current density (Jc) in zero magnetic fields for each sample was measured from 40 K to transition temperature (Tc). It was found that the Jc value decreased with increasing temperature and this showed the consequence of thermal activated flux creep. Using the self-field approximation together with Jc dependence on temperature, we estimated that the characteristic length (Lc) associated with the pinning force is approximately the same as the average grain size (Rg) for the non-added sample and for sample with 8% nanosize MgO addition. In contrast, for samples with 3% and 5% addition, the results showed that Lc < Rg. This indicates that addition of 3% to 5% of nanosize MgO particles provides the optimum flux pinning centers for Bi-2212 superconductor ceramics. � 2012 American Institute of Physics.