THEORETICAL STUDY OF SUPERCONDUCTIVITY AND MAGNETISM IN ELECTRON DOPED BARIUM IRON ARSENID Ba SUPERCONDUCTOR

ABSTRACT Superconductivity is characterized by disappearance of electrical resistivity and expulsion of magnetic field from the interior of a solid. This research work focuses on the theoretical study of the possible coexistence of superconductivity and magnetism in Ba superconductor. The interaction between superconductivity and magnetism state was studied in barium iron arsenide (Ba ) iron based superconductivity. The interactions have been studied based on two band model Hamiltonian, and use Bogoliubov transformation formalism. By developing a two band model Hamiltonian for the given systems & using the Bogoliubov transformation formalism, we obtained mathematical expressions for superconducting transition temperature and magnetic transition temperature, as a function of order parameter have for Ba . The phase diagram of superconducting and spin density wave temperatures as a function of magnetic order parameter of Ba , shows that the superconducting transition temperature decreases as the increase of the spin density wave order parameter. The spin density wave transition temperature increases with increase of the spin density wave order parameter. The combined phase diagram of superconducting and spin density wave temperature as a function of magnetic order parameter shows that superconducting and spin density wave coexistence in some range of magnetic order parameter in Ba which is in broad agreement with experiment observations.