Peculiarity of topological Hall effect in Mn2Sb0.9Bi0.1 ferrimagnet.

The substituted Mn₂Sb-based ferrimagnetic (FIM) alloys by other elements have attracted much attention recently due to excellent magneto-functional properties. However, almost all investigations have been concentrated on the first-order phase transition between antiferromagnetic and FIM state. In this work, a large topological Hall effect (THE) associated with the spin reorientation transition is observed in the Mn₂Sb_0.9Bi_0.1 alloy. Strikingly, the sign reversal of topological Hall resistivity ( ρ x y T ) is found before and after the SRT temperature T_SR ∼260 K. Above the T_SR, a positive ρ x y T is observed, e.g., ∼0.52 μΩ cm at 320 K. By reducing temperature to 275 K, the ρ x y T value decreases to ∼0.42 μΩ cm. It is interesting that, however, the negative ρ x y T value is found below the T_SR, e.g., ∼−0.66 μΩ cm at 175 K. The physical mechanism about this peculiar THE is discussed in Bi-doped Mn₂Sb-based alloys. [ABSTRACT FROM AUTHOR]