Elastic theory for the vortex-lattice melting in iron-based high-Tc superconductors

The vortex-lattice melting transitions in two typical iron-based high-Tc superconductors Ba(Fe1-xCox)2As2 (122-type) and Nd(O1-xFx)FeAs (1111-type) for magnetic fields parallel and perpendicular to the anisotropy axis are studied within the elastic theory. Using the parameters from experiments, the vortex-lattice melting lines in the H-T diagram are located systematically by various groups of Lindemann numbers. It is observed that the theoretical results for the vortex melting on both superconductors Ba(Fe1-xCox)2As2 and Nd(O1-xFx)FeAs for parallel fields agree well with the recent experimental data. The future experimental results for the vortex melting can be compared with the present theoretical prediction by tuning reasonable Lindemann numbers.