Aging of Sr2FeMoO6 and related oxides

The structural stability of the ferromagnetic and metallic double perovskites such as Sr2FeMoO6 has been explored using X-ray diffraction and Raman spectroscopy. It is found that under air atmosphere, at room temperature, the unit cell expands with time and gradually decomposes into SrMoO4. At higher temperatures the decomposition proceeds faster. Whereas in sintered pellets, the effect of this structural transformation on the transport properties is moderate, it becomes dramatic on granular thick films prepared by screen printing. The relevance of these findings for possible technological applications of Sr2FeMoO6 is discussed.