Raising the Curie temperature in (formula presented) double perovskites by electron doping

Electron doping in the ferromagnetic and metallic double perovskites (formula presented) is achieved via the partial substitution of (formula presented) by (formula presented) We show that this doping promotes an extraordinary rising of the Curie temperature of about 70 K above that of the pristine compound. This finding reveals that the ferromagnetic coupling is mediated by itinerant carriers, thus providing solid experimental support to the double-exchange picture for the magnetic interactions. The observation that (formula presented) can be substantially enhanced may be of relevance for technological applications of these materials in advanced spin devices. © 2001 The American Physical Society.