Phase Formation and Magnetoresistance of Double Perovskite Sr ₂ FeMoO ₆

Abstract

Phase formation behaviors of double perovskite Sr 2 FeMoO 6 (SFMO) derived from mechanical activation were investigated. Polycrystalline double perovskite SFMO of grain sizes in nanometer range were synthesized by heat treatment of the precursors derived from mechanical activation of SrO, Fe 2 O 3 , and MoO 3 at temperatures in the range of 600°–900°C in flowing atmosphere of H 2 /Ar. Mechanical activation at room temperature led to formation of SFMO at 700°C, which is about 200°C lower than what is required in the conventional solid state reaction. The magnetization of thus‐derived SFMO increases with increasing heat‐treatment temperature in the range of 700°–900°C. Similarly, its magnetoresistance ratio also increases with increasing heat‐treatment temperature, which is accounted for by the elimination of insulating SrMoO 4 impurity phase and enhancement in crystallinity of the double perovskite SFMO phase.