Magnetic structure of EuTe4 and its evolution in a magnetic field

The coupling between charge density waves (CDWs) and magnetism in rare-earth tellurides could offer a unique platform for exploring and controlling quantum states. We propose to determine the magnetic structure of EuTe4, a novel van der Waals semiconductor hosting a unique, electrically-controllable and polar CDW order. While data show an antiferromagnetic transition at 7 K, the magnetic structure and its interplay with the CDW state remain unknown. We will use WISH to perform a comprehensive two-part experiment. First, a powder diffraction study will determine the zero-field magnetic structure and its thermal evolution. For the second part, a single-crystal experiment will map the evolution of the magnetic order through a field-induced metamagnetic transition. The high flux and low background of WISH are essential for overcoming the strong neutron absorption of Eu, while its high resolution is required to resolve the potentially incommensurate magnetic order. The experiment will provide foundational knowledge on the coupling between magnetism and a polar, switchable CDW. This experiment will be the first neutron diffraction study on EuTe4.