Magnetic excitations as a function of field in the topological f-electron magnet CeAgBi2

Recently, the first f-electron skyrmions were reported to emerge in a row of Gd-based bulk materials including Gd2PdSi3. In contrast to the well known skyrmion materials like MnSi, these f-electron skyrmions do not require inversion symmetry breaking. Yet, an account of the underlying spin-spin interactions that instead lead to skyrmion lattice order remains elusive. Neutron spectroscopy, a technique that typically qualifies for the study of the microscopic interactions, is prevented in these materials due to the large neutron absorption of Gd. We identified by means of neutron diffraction the tetragonal heavy-fermion magnet CeAgBi2 as another centrosymmetric f-electron material that hosts skyrmion-lattice order. As a cerium-based compound, CeAgBi2 is ideally suited for neutron spectroscopy measurements, which we here propose to perform at LET.