题目：Diamagnetization above and below critical temperature in High TC superconductors
地点：东南大学物理系田家炳南楼203
时间：2014年11月10号下午2点
主讲人：李定平 教授
单位：北京大学7163银河官方网址
邀请人：施智祥 教授
报告摘要：Recent measurements of fluctuation diamagnetism in high-temperature superconductors show distinct features above and below Tc, which can not be explained by simple Gaussian fluctuation theory. Self-consistent calculation of magnetization in layered high-temperature superconductors, based on the Ginzburg-Landau-Lawrence-Doniach model and including all Landau levels is presented. The results agree well with the experimental data in a wide region around Tc, including both the vortex liquid below Tc and the normal state above Tc. The Gaussian fluctuation theory significantly overestimates the diamagnetism for strong fluctuations. It is demonstrated that the intersection point of magnetization curves appears in the region where the lowest Landau level contribution dominates and magnetization just below Tc is nonmonotonic. Our calculation supports the phase disordering picture of fluctuations above Tc.