Magnetic structures and metamagnetic transition of non-centrosymmetric helimagnet ScFeGe

We have investigated the magnetic, transport and structural properties of non-centrosymmetric (NCS) ScFeGe that crystallizes in the Fe₂P-type hexagonal crystal structure with lattice parameters c < a. The temperature dependence of the magnetization indicates a magnetic transition at T_N = 40 K. The single-crystal neutron diffraction studies indicates a helical magnetic order with wavevector k = (0 0 0.193) and a magnetic moment ≈ 0.53µ_B (confined to the ab plane), indicating highly itinerant magnetic system. Itinerant magnetic systems where the Dzyaloshinskii–Moriya interaction is allowed are very interesting because of the effect on the magnetic states and because of fundamental questions about the origins of the interaction itself. We also demonstrate that the newly synthesized NCS helimagnet ScFeGe shows metamagnetic transition simultaneously with the appearance of a long wavelength (≈390 Å) modulation of the magnetic structure. Our observations also strongly suggest the existence of magnetostructural coupling in ScFeGe, which is likely driven by spin-orbit coupling and the DM interaction. In addition, our charge transport measurements display a discontinuous change to the resistivity along with a change in the sign of the magnetoresistance (MR) at T_N.