Influence of the modulating interfacial state on Sr2FeMoO6 powder magnetoresistance properties

In this paper, we studied the effects of the modulating interfacial state, which was introduced by mechanical ball milling, on the magnetoresistance (MR) properties of Sr2FeMoO6 polycrystalline material. The X-ray diffraction analysis showed that the crystal structure of Sr2FeMoO6 polycrystalline material was not changed in the process of ball milling, but the SrMoO4 impurity phase was introduced at grain boundaries, and its quantity increased with the milling time. The results of resistance measurements at different temperatures indicated that ball milling had a very important influence on the MR properties. At T<50 K, due to the enhancement of the tunneling among adjacent grains by introducing the insulating SrMoO4 phase at grain boundaries, the MR was enhanced with increasing the milling time. However, at T>50 K, the MR decreased rapidly with the increase in milling time. This phenomenon was mainly caused by the inelastic hopping of electrons through the localized states introduced at grain boundaries.