  Oxide materials exhibit several novel structural, magnetic, and electronic
properties. Their stability under ambient conditions, easy synthesis, and high
transition temperatures provide such systems with an ideal ground for realizing
topological properties and real-life technological applications. However,
experimental evidence of topological states in oxide materials is rare. In this
study, we have synthesized single crystals of oxide double perovskite Sr2FeMoO6
and revealed its topological nature by investigating its structural, magnetic,
and electronic properties. We observed that the system crystallized in the
cubic space group Fm-3m, which is a half-metallic ferromagnet. Transport
measurements show an anomalous Hall effect, and it is evident that the Hall
contribution originates from the Berry curvature. Assuming a shift of the Fermi
energy towards the conduction band, the contribution of the anomalous Hall
effect is enhanced owing to the presence of a gaped nodal line. This study can
be used to explore and realize the topological properties of bulk oxide
systems.
