In multilayered magnetic topological insulator structures, magnetization reversal processes can drive topological phase transitions between quantum anomalous Hall, axion insulator, and normal insulator states. Here we report an examination of the critical behavior of two such transitions: the quantum anomalous Hall to normal insulator (QAH-NI), and quantum anomalous Hall to axion insulator (QAH-AXI) transitions. By introducing a new analysis protocol wherein temperature dependent variations in the magnetic coercivity are accounted for, the critical behavior of the QAH-NI and QAH-AXI transitions are evaluated over a wide range of temperature and magnetic field. Despite the uniqueness of these different transitions, quantized longitudinal resistance and Hall conductance are observed at criticality in both cases. Furthermore, critical exponents were extracted for QAH-AXI transitions occurring at magnetization reversals of two different magnetic layers. The observation of consistent critical exponents and resistances in each case, independent of the magnetic layer details, demonstrates critical behaviors in quantum anomalous Hall transitions to be of electronic rather than magnetic origin. Our finding offers a new avenue for studies of phase transition and criticality in QAH insulators.

在多层磁拓扑绝缘体结构中，磁化反转过程可以驱动量子反常霍尔、轴子绝缘体和正常绝缘体状态之间的拓扑相变。在这里，我们报告了对两种此类转变的关键行为的检查：量子反常霍尔到正常绝缘体（QAH-NI）和量子反常霍尔到轴子绝缘体（QAH-AXI）转变。通过引入新的分析协议（其中考虑了磁矫顽力的温度依赖性变化），可以在广泛的温度和磁场范围内评估 QAH-NI 和 QAH-AXI 转变的关键行为。尽管这些不同转变具有独特性，但在两种情况下都观察到了临界的量子化纵向电阻和霍尔电导。此外，提取了两个不同磁性层磁化反转时发生的 QAH-AXI 转变的关键指数。在每种情况下观察到一致的临界指数和电阻，与磁性层细节无关，证明了量子反常霍尔跃迁中的关键行为是电子起源的，而不是磁性起源的。我们的发现为 QAH 绝缘体的相变和临界性研究提供了新途径。