Coexistence of Itinerant Ferromagnetism and Superconductivity in ZrZn2

A microscopic coexistence of itinerant ferromagnetism and superconductivity is studied in a single- band homogeneous system, using an equation of motion method and Green’s function technique. Self-consistent equations for the superconducting order parameter Δ and magnetization m are derived. It is shown that there generally exists coexistent (Δ≠0 andm≠0) solutions to the coupled equations of the order parameters in the temperature range 0