Topological Hall signatures of magnetic hopfions

The authors calculate the topological Hall conductivity of electrons in a magnetic hopfion. This nano-object is a noncollinear spin texture that gives rise to a locally uncompensated emergent magnetic field. Due to this field, a hopfion exhibits a distinct topological Hall signature that can be useful for spintronic applications. One simulated example is a mechanism for detecting hopfions in racetrack data storage devices.