Magnetic order of correlated hourglass fermion candidate Eu5In2Sb5

A new kind of topologically protected electronic state has been predicted in crystals whose surfaces form atomic patterns with certain non-symmorphic symmetries. Eu5In2Sb6 is one candidate for this phenomenon, and is of special interest because this topology may here be coupled to a large ordered magnetic moment. Indeed, we found unusual transport properties that are linked to its low-temperature antiferromagnetic phases. Eu5In2Sb6 has two magnetic transitions, at 14 K and 7.5 K. Using resonant x-ray scattering (REXS), we recently determined the spin-arrangement below 7.5 K. However, we did not find the magnetic propagation vector in the intermediate (7.5-14K) phase. We therefore propose a short and simple neutron diffraction experiment which will inform the continuation of our REXS study. This should elucidate the apparent competition of magnetic couplings in this material.