An intrinsic magnetic tunnel junction An electrical current running through two stacked magnetic layers is larger if their magnetizations point in the same direction than if they point in opposite directions. These so-called magnetic tunnel junctions, used in electronics, must be carefully engineered. Two groups now show that high magnetoresistance intrinsically occurs in samples of the layered material CrI3 sandwiched between graphite contacts. By varying the number of layers in the samples, Klein et al. and Song et al. found that the electrical current running perpendicular to the layers was largest in high magnetic fields and smallest near zero field. This observation is consistent with adjacent layers naturally having opposite magnetizations, which align parallel to each other in high magnetic fields. Science, this issue p. 1218, p. 1214 The atomic layers of the material CrI3 act as spin filters in graphite/CrI3/graphite junctions. Magnetic insulators are a key resource for next-generation spintronic and topological devices. The family of layered metal halides promises varied magnetic states, including ultrathin insulating multiferroics, spin liquids, and ferromagnets, but device-oriented characterization methods are needed to unlock their potential. Here, we report tunneling through the layered magnetic insulator CrI3 as a function of temperature and applied magnetic field. We electrically detect the magnetic ground state and interlayer coupling and observe a field-induced metamagnetic transition. The metamagnetic transition results in magnetoresistances of 95, 300, and 550% for bilayer, trilayer, and tetralayer CrI3 barriers, respectively. We further measure inelastic tunneling spectra for our junctions, unveiling a rich spectrum consistent with collective magnetic excitations (magnons) in CrI3.

中文翻译：

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通过电子隧道探测二维范德华结晶绝缘体的磁性

本征磁隧道结 如果两个堆叠的磁性层的磁化强度指向相同的方向，则流过两个堆叠的磁性层的电流比它们指向相反的方向时要大。这些用于电子产品的所谓磁隧道结必须经过精心设计。两组现在表明，高磁阻本质上发生在夹在石墨触点之间的层状材料 CrI3 样品中。通过改变样本中的层数，Klein 等人。和宋等人。发现垂直于层运行的电流在高磁场中最大，而在零场附近最小。这一观察结果与自然具有相反磁化强度的相邻层一致，它们在高磁场中彼此平行排列。科学，这个问题 p。1218 页。1214 CrI3 材料的原子层充当石墨/CrI3/石墨结中的自旋过滤器。磁性绝缘体是下一代自旋电子和拓扑器件的关键资源。层状金属卤化物家族有望提供多种磁性状态，包括超薄绝缘多铁性、自旋液体和铁磁体，但需要面向器件的表征方法来释放它们的潜力。在这里，我们报告了穿过层状磁性绝缘体 CrI3 的隧道效应作为温度和外加磁场的函数。我们用电检测磁基态和层间耦合，并观察到场诱导的超磁跃迁。变磁转变导致双层、三层和四层 CrI3 势垒的磁阻分别为 95%、300% 和 550%。