Observation of record flux pinning in melt-textured NEG-123 superconductor doped by Nb, Mo, and Ti nanoparticles |
| |
Authors: | M Muralidhar M Tomita M Jirsa N Sakai M Murakami I Hirabayashi |
| |
Institution: | aRailway Technical Research Institute (RTRI), Applied Superconductivity, Materials Technology Division, 2-8-38, Hikari-cho, Kokubunji-shi, Tokyo 185-8540, Japan;bSuperconductivity Research Laboratory (SRL), 1-10-13, Shinonome, Tokyo 135-0062, Japan;cInstitute of Physics, ASCR, CZ-182 21 Praha 8, Czech Republic;dShibaura Institute of Technology, Shibaura 3-9-14, Minato-ku, Tokyo 108-8548, Japan |
| |
Abstract: | Flux pinning in melt-processed (Nd0.33Eu0.33Gd0.33)Ba2Cu3Oy “NEG-123” + 35 mol% Gd2BaCuO5 “NEG-211” (70 nm in size) composite doped by TiO3, MoO3 and Nb2O5 achieved record values. The optimum values of all three dopands were found to be around 0.1 mol%. Transmission electron microscope (TEM) analysis found clouds of <10 nm sized particles in the NEG-123 matrix, shifting the pinning particle size distribution to significantly lower values. TEM by energy dispersive X-ray spectroscopy (EDX) analysis clarified that these nanoparticles contained a significant amount of Nb, Mo, and Ti. Appearance of nanometer-sized defects correlated with a significantly improved flux pining at low and medium magnetic fields, which was particularly significant at high temperatures. In the Nb-doped sample, a record Jc value of 925 kA/cm2 at the secondary peak field (4.5 T) was achieved at 65 K, 640 kA/cm2 at zero field at 77 K, and 100 kA/cm2 at 90.2 K, the last value having been up to now considered as a good standard for REBa2Cu3Oy “RE-123” materials at 77 K. The greatly improved Jc–B performance in Nb/Mo/Ti doped samples can be easily translated to large-scale LRE-123 (LRE = light rare earths, Nd, Eu, Gd, Sm) blocks intended for real superconducting super-magnets applications. |
| |
Keywords: | NEG superconductor TEM Nanoparticles Flux pinning High Jc LRE-Ba2Cu3Oy |
本文献已被 ScienceDirect 等数据库收录! |
|