Enhanced intergrain magnetoresistance Sr/sub 2/FeMoO/sub 6/

Summary form only given. The half-metallic double perovskite Sr/sub 2/FeMoO/sub 6/ has attracted interest compared to the optimally doped mixed valent manganites due to its potential for use in magnetoelectronic devices. It has a high Curie temperature and enhanced low field magnetoresistance at room temperature. Since the low field magnetoresistance is dominated in these materials by intergrain transport, we have synthesized ceramic material with nanometer-size crystallite polycrystals by a novel combustion synthesis method in an effort to improve the magnetoresistive response. We compare the magnetoresistance of samples prepared by solid state reaction and combustion synthesis in both low (< 1 T) and high (up to 25 T) magnetic fields. The existence of useful magnetoresistance above room temperature together with the large temperature independent low-field response makes these materials promising for magnetoresistive devices.