Ferromagnetic coupling strength and electron-doping effects in double perovskites

We review experiments and results on ferromagnetic and metallic A2FeMoO6 double perovskites that made it possible to obtain a detailed understanding of the nature of the ferromagnetic coupling and paved the way for further enhancement of the Curie temperature. We show that appropriate chemical substitutions, combined with detailed structural, magnetotransport and spectroscopic data allow us to map quite a complete picture of the properties of these oxides.