Fig. 3: Magnetism characterization of Mn(Bi_1-xSb_x)₂Te₄.

a Temperature dependence of magnetic susceptibility for various Sb content x. The curves are measured in FC condition with a field of 500 Oe applied along the c axis. The values of T_N are marked with a purple dashed line. b Magnetic field dependence of magnetization for Sb content ranging from x = 0 to 0.26 at 2 K. c Magnetic field dependence of magnetization for Sb content x = 0.04 at different temperatures. d–f Critical fields for the spin-flop transition and saturation (H_c1 and H_c2) extracted from M(H) curves by identifying the dM/dH peaks and d²M/dH² valleys, respectively. The variations of H_c1 and H_c2 with temperature and Sb content x are illustrated in a three-dimensional diagram (f). The X-Z cut (d) and Y-Z cut (e) of the 3D figure show the dependence of H_c1 and H_c2 on Sb content x and the magnetic transitions at different temperatures.