MAGNETISM AND SUPERCONDUCTIVITY IN Ba2-x N A SUPERCONDUCTOR

ABSTRACT In this work, the competition between superconductivity and magnetism have been examined and explained in nickel doped barium iron arsenide (BaF A superconductor. The work focuses on the theoretical investigation of the mathematical expressions for superconducting transition temperature, anti-ferromagnetic ordering transition temperature, the superconducting order parameter and anti- ferromagnetic order parameter by developing a model Hamiltonian for the system and using the retarded double time temperature dependent Green’s function formalism. Then by employing the experimental and theoretical values of the parameters in the obtained mathematical expressions, phase diagrams of the superconducting transition temperature versus superconducting order parameter, anti-ferromagnetic transition temperature versus magnetic order parameter and superconducting transition temperature versus magnetic order parameter have been plotted. Finally by combining superconducting transition temperature versus magnetic order parameter graph with magnetic ordering transition temperature versus magnetic order parameter graph we have demonstrated the possible coexistence of superconductivity and magnetism in nickel doped barium iron arsenide (BaF N A ) superconductor. The relation between superconducting transition temperature with superconducting order parameter, magnetic ordering transition temperature with magnetic order parameter and superconducting transition temperature with magnetic order parameter have been clearly explained based on the obtained equations and from the graphs