Enhanced low field magnetoresistance in Sr2FeMoO6-glass composites

In this paper, we report the enhancement of the low field magnetoresistance in Sr2FeMoO6-glass composites with different wt% percents of glass. The crystal structure of Sr2FeMoO6 does not change by adding glass, and the glass is most likely located at the grain boundaries. The low field magnetoresistance up to 1 T of Sr2FeMoO6-glass composites at 10 K all shows obvious butterfly-shaped field dependence other than the pure Sr2FeMoO6 bulk sample. The magnetoresistance of Sr2FeMoO6-glass composites at 10 K is enhanced gradually with increasing the glass concentration and reaches 39% with a wt% of 50%. The enhancement of low field magnetoresistance in Sr2FeMoO6-glass composites can be well explained by the spin-dependent tunneling at the glass boundaries, and it also allowed us to conclude that the spin polarization of Sr2FeMoO6 is at least 80% at low temperature.