Study of Vortex Pinning Effect in Composite Arrays with Different Pinning Sites in Superconducting Nb Film

• Main Authors: Sheng Hao Wang, 王聖豪
• Other Authors: Lance Horng
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/68309665880289634072

碩士 === 國立彰化師範大學 === 物理學系 === 100 === In type II superconductor, magnetic fields can penetrate into the superconductor inhomogeneously as an array of vortices. The interaction of these vortices and vortex-pin effect in the superconductor give rise to a rich variety of static and dynamical phases. In our study, a series of different pinning sites at the center of every hexagonal cell are added. The diameter of the defects of every hexagonal cell is 300 nm. And the diameters of different pinning sites at the center are 0, 100, 200, and 300 nm. Special matching peaks of critical currents are exhibited at different temperatures in the measurements. The positions and structures of the matching peaks seem irregular and are very different from the structures of the matching peaks for previously explored films, such as films with triangular, square, or honeycomb pinning arrays. Compared with different electrical measured curves of each samples, the relation of multiple-vortex filling up different pinning sites can be explained reasonably. Simulations of vortices behavior in unit pinning site of honeycomb array with different number of magnetic flux quantum are investigated. The phenomenon of interstitial vortex occurred in the center of honeycomb is found in the simulation.