A Macroscopic Theory of Magnetoelastic Superconductors

A macroscopic theory for investigating novel phenomena in elastic ferromagnetic superconductors is being developed in this article, where interaction between magnetoelasticity and superconductivity is taken into account. The formulation of this theory is based on the generalization of the well-known Ginzburg-Landau theory and the micromagnetics together with the use of a finite strain theory which may ensure a consistent treatment of different-order-effects. The magnetoelastic properties of ferromagnetic superconductors and the possible coexistence of superconducting and ferromagnetic phases are then studied with the aid of this theory. The results show how the elastic, the magnetostrictive and the magnetic anisotropic properties of the ferromagnetic superconductors are influenced by superconducting phase transition, and give the conditions for the coexistence of certain types of superconducting and ferromagnetic phases in the ferromagnetic superconductors.