Anomalous magnetoresistance in detwinned EuFe₂As₂

The in-plane magnetotransport of detwinned EuFe₂As₂ single crystal has been investigated. In the antiferromagnetic phase of Eu²⁺ spins, very different magnetoresistance results are observed upon the change of the external magnetic field direction and the current direction. This could be attributed to the tunable orientation of the Eu²⁺ spins under magnetic field. Electron scattering by spin fluctuation, superzone boundary effect, and cyclotron motion of charge carriers are used to interpret the observed anomalous magnetoresistance which is measured by using a current along a direction. The remarkable features of magnetoresistance suggest that itinerant electrons strongly couple with the spin configuration of Eu²⁺, which has a huge influence on the transport properties of EuFe₂As₂. (paper)