A peculiar topological Hall effect in noncentrosymmetric ternary carbide GdCoC2.

A peculiar topological Hall effect (THE) is reported in a noncentrosymmetric ternary carbide GdCoC₂. The GdCoC₂ reveals a magnetic ordering transition from paramagnetic to ferromagnetic state at the Curie temperature T_C = 15.6 K, followed by a commensurate-incommensurate phase transition at T_t = 14.1 K. Below T_t, the competition between an external magnetic field and magnetic interactions, including the Dzyaloshinskii–Moriya interaction, would give rise to characteristic spin textures with non-zero scalar spin chirality χ ijk , or even topologically protected spin configurations like skyrmions, for which the exotic spin-charge coupled phenomena are induced. Besides a large negative magnetoresistance (MR) up to ∼−52% at 14 K, a remarkably sharp topological Hall signal is observed with almost no anomalous Hall resistivity below 10 K. The topological Hall resistivity ( ρ xy T ) of GdCoC₂ reaches a maximum value of ∼0.23 μΩ cm at 3 K under μ₀H = 0.6 T. The mechanism underlying the exceptional THE with relatively large ρ xy T value in GdCoC₂ is discussed in detail. [ABSTRACT FROM AUTHOR]