Condensed-Matter Physics & Materials Science Seminar
"Flux Pinning Engineering for Applications of High-Tc Superconductors"
Presented by Kaname Matsumoto, Department of Materials Science and Engineering, Kyushu Institute of Technology, Japan
Monday, July 15, 2013, 10:30 am
Bldg. 480 conference room
Hosted by: Qiang Li
In type-II superconductor including NbTi, Nb3Sn, MgB2, FBS (Fe-based superconductor), HTS (high Tc superconductor), energy dissipation is associated with the motion of vortex lattice in a form of vortex flow or creep. This dissipation is reduced by the presence of crystalline defects, namely "flux pinning". Below Jc, the defects pin quantized vortices and provide supercurrent without energy dissipation. An important challenge in application of type-II superconductors for large scale is increasing Jc under magnetic field at selected temperatures. Introduction of titanium precipitates in NbTi wires and grain boundaries in Nb3Sn and MgB2 wires are successful technique for controlling Jc. And also, self-assembled compound nanorods, such as BaZrO3, BaSnO3, etc for YBCO coated conductors and recently developed BaFeO2 nanotods for FBS films, are very effective pinning centers for enhancing Jc, as well as compound nanoparticles. Flux pinning in type II superconductor has attracted much attention from technological and scientific point of views and has fascinated many researchers so far. In this plenary talk, the recent development of flux pinning technology in several materials will be reviewed. Additionally, the complex pinning phenomena will be visualized based on 2D- and 3D- time dependent Ginzburg-Landau (TDGL) simulation, and the possible pinning structure for further increasing Jc will be discussed.