We demonstrate precise control of magnetism in ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ thin films through careful synthesis by molecular beam epitaxy, achieving minimal defects and accurate layer thickness control. By optimizing Mn-Bi-Te ratios and growth temperatures, we minimize detrimental self-doping effects and accurately target integer-layer films. X-ray diffraction and reflectivity provide quantitative measures of film quality and thickness. When these macroscale probes of structure and thickness are integrated with magnetotransport measurements, a striking even-odd layer dependence of the anomalous Hall effect is revealed. Odd-layer films exhibit a large hysteresis up to the Néel temperature ($\sim 25\mathrm{K}$), consistent with noncompensated antiferromagnetism, while even-layer films show minimal response, as expected for an antiferromagnet. The sign of the anomalous Hall effect exhibits a sign reversal for intrinsic magnetism versus magnetism associated with defects. This work identifies critical factors for inducing pure, noncompensated ferromagnetism and reveals the characteristics of the intrinsic anomalous Hall effect in ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$, which together is a step toward realizing the zero-field quantum anomalous Hall effect in topological materials.

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• Anomalous Hall effect
• Chern insulators
• Electrical properties
• Quantum anomalous Hall effect
• Topological insulators
• Antiferromagnets
• Topological materials
• Molecular beam epitaxy
• Resistivity measurements
• X-ray diffraction