Metallic ferromagnetism with large coercive field in intercalated Fe0.5-xTixTiS2

Abstract

Among the transition metal dichalcogenides, iron-intercalated TiS₂ exhibits antiferromagnetism with a large coercive field at the metamagnetic transition when y ≈ 0.5 in Fe_yTiS₂. This composition region marks the transition in the ground state from an antiferromagnetic metal to ferromagnetic insulator. Nonetheless, as y increases near y = 0.5 in Fe_yTiS₂, the charge carrier concentration increases, going with Fe substitution for Ti in the TiS₂ slabs (y > 0.5) that hinders a ferromagnetic metal to be set. To avoid it, a series of Fe_0.5-xTi_xTiS₂ samples (0≤x ≤ 0.075) was studied. Seebeck measurements confirm that despite the x increase, the charge carrier concentration remains constant. As a result, the T-dependent magnetic susceptibility and electrical resistivity reveal that a change from antiferromagnetic metal (x = 0.00) to a ferromagnetic metal (x > 0.00) can be induced, with a transition temperature decreasing from T_N = 140K (x = 0.00) to T_C = 130K (x = 0.075). This metallicity increase in the ferromagnetic state reflects the reduced charge scattering responsible for the peak at T_C of the negative magnetoresistance. Both very large H_c values, such as μ₀H_c = 7.2T at 5K for Fe_0.425Ti_0.075TiS₂, and magnetization jumps at 2K in the M(H) loops are observed.