Tailoring of flux pinning force in BSCCO superconductor
Significant variations in microstructure, self- and in-field JCs at 64 K and flux pinning properties have been observed for La substituted Bi1.6Pb0.5Sr2Ca1.1Cu2.1O8+? superconducting samples with respect to sintering temperature. The sample sintered at 858o C showed best self-field JC while that sintered at 846 oC showed the best in-field JC due to the changes in microstructure. The activation energy of flux motion (pinning potential Uo) was estimated from the field dependent resistivity-temperature curves, and the flux pinning force (FP) from the field dependent JC values. The La-doped samples, sintered at 846o C showed maximum FP and Uo of 463 kNm-3 and 0.380 ± 0.001 eV as against 93.6 kNm-3 and 0.140 ± 0.001 eV, respectively for the sample sintered at 858o C. The undoped (Bi,Pb)-2212 showed a maximum FP and Uo of 12.7 kNm-3 and 0.074 ± 0.001 eV, respectively. The origin of these enhanced properties is mainly from the normal-like defects introduced by optimum La-doping at the Sr-site, at an optimum sintering temperature.
Materials Science and Technology