Enhanced magnetoresistance in Sr2FeMoO6 by combustion synthesis

A novel method of producing magnetoresistive oxides is described, which involves low temperature combustion synthesis from a mixture of nitrates and fuel, as applied to Sr2FeMoO6. The method yields ceramics with a fine crystallite size of 100–200 nm and a room temperature resistivity of 200 mV m. Low field magnetoresistance (6.5% in 0.1 T) is enhanced dramatically compared to samples prepared by conventional solid-state reaction due to the efficient intergrain tunnelling arising from the high density of grain boundaries. Magnetoresistance in low fields is essentially independent of temperature from 5–300 K, and it persists up to 350 K, providing the prospect of sensor applications in an extended temperature range.