Magnetic Order of Dresselhaus-type Antiferromagnet EuIr$_4$In$_2$Ge$_4$ Studied by Single Crystal Neutron Diffraction

Abstract

The magnetic order of EuIr$_4$In$_2$Ge$_4$, which crystallizes in a Dresselhaus-type noncentrosymmetric tetragonal structure, was investigated using two complementary single-crystal neutron diffraction approaches. Time-of-flight single-crystal diffraction reveals antiferromagnetic Bragg reflections with propagation vector $q = (1, 0, 0)$ below the N\'{e}el temperature $T_{\rm N}$ = 2.5 K, indicating a breaking of body-centered translational symmetry. Polarized neutron diffraction on a triple-axis spectrometer demonstrates that the ordered Eu$^{2+}$ $4f$ moments lie within the basal plane and form a collinear antiferromagnetic structure with antiparallel alignment between corner and body-center sites. Despite the Dresselhaus-type spin splitting in the conduction bands, the magnetic order remains simple, implying weak coupling between localized moments and itinerant electrons.