CrI3, which belongs to a rare category of two-dimensional (2D) ferromagnetic semiconductors, is of great interest for spintronic device applications. Unlike CrCl3 whose magnetism presents a 2D-Heisenberg behavior, CrI3 exhibits a larger van der Waals gap, smaller cleavage energy, and stronger magnetic anisotropy which could lead to a 3D magnetic characteristic. Hence, we investigate the critical behavior of CrI3 in the vicinity of magnetic transition. We use the modified Arrott plot and Kouvel-Fisher method, and conduct critical isotherm analysis to estimate the critical exponents near the ferromagnetic phase transition. This shows that the magnetism of CrI3 follows the crossover behavior of a 3D-Ising model with mean field type interactions where the critical exponents \b{eta}, {\gamma}, and {\delta} are 0.323, 0.835, and 3.585, respectively, at the Curie temperature of 64 K. We propose the crossover behavior can be attributed to the strong uniaxial anisotropy and inevitable interlayer coupling. Our experiment demonstrates the applicability of crossover behavior to a 2D ferromagnetic semiconductor.

中文翻译：

---

二维本征铁磁半导体CrI3的临界行为

CrI3 属于一种罕见的二维 (2D) 铁磁半导体，在自旋电子器件应用中具有重要意义。与磁性呈现 2D-Heisenberg 行为的 CrCl3 不同，CrI3 表现出更大的范德华间隙、更小的解理能和更强的磁各向异性，这可能导致 3D 磁特性。因此，我们研究了 CrI3 在磁转变附近的临界行为。我们使用改进的 Arrott 图和 Kouvel-Fisher 方法，并进行临界等温线分析来估计铁磁相变附近的临界指数。这表明 CrI3 的磁性遵循具有平均场类型相互作用的 3D-Ising 模型的交叉行为，其中临界指数 \b{eta}、{\gamma} 和 {\delta} 为 0.323、0.835 和 3.585，分别，在 64 K 的居里温度下。我们认为交叉行为可归因于强单轴各向异性和不可避免的层间耦合。我们的实验证明了交叉行为对二维铁磁半导体的适用性。