**Fig. 3.** Magnetic and magneto-transport properties of MnBi$_{2}$Te$_{4}$ films. (a) Magnetization vs magnetic field ($M$–$H$) of the 7-SL MnBi$_{2}$Te$_{4}$ film measured with SQUID at 3 K (red), 15 K (light green), 20 K (green), and 30 K (blue), respectively. $H$ is perpendicular to the sample plane. The inset shows the $M$–$H$ curves measured with $H$ perpendicular to (red) and in (blue) the sample plane (a different 7-SL MnBi$_{2}$Te$_{4}$ sample). (b) Temperature dependences of the remnant magnetization ($M_{\rm r}$) and zero-magnetic-field Hall resistance ($R_{yx}^{0}$) of the 7-SL film, which give the Curie temperature ($T_{\rm C}$). (c) $M$–$H$ curves of the 6 SL MnBi$_{2}$Te$_{4}$ film measured with SQUID at 3 K (red), 15 K (light green), 20 K (green), and 30 K (blue). $H$ is perpendicular to the sample plane. (d) $R_{yx}$–$H$ curves measured at 1.6 K at different gate voltages. (e) $M$–$H$ curves of 4, 5, 6, 7, 8, 9-SL MnBi$_{2}$Te$_{4}$ films measured at 3 K and right above $T_{\rm C}$ (upper panels) and the differences between the curves at the two temperatures (lower panels). (f) Thickness dependences of $M_{\rm r}$ at 3 K, $M_{\rm r}$ difference at 3 K and above $T_{\rm C}$ (upper panel) and $H_{\rm c}$ (lower panel). (g) $R_{yx}$–$H$ curve of the 7-SL MnBi$_{2}$Te$_{4}$ film measured at 1.6 K with $H$ up to 9 T. The blue arrows indicate the magnetic configurations at different $H$. Each arrow represents the magnetization vector of an SL. In (e) and (f), (1/2) means that the displayed magnetization has been multiplied by 1/2 for sake of comparison.