van der Waals (vdW) intrinsic magnets are promising for miniaturization of devices beyond Moore's law for future energy efficient nanoelectronic devices and have been successfully used for constructing high performance vdW magnetic tunnel junctions (vdW MTJs). Here, using first principles calculations, we investigate the magnetic anisotropy, spin-dependent transport and tunneling magnetoresistance (TMR) effect of vdW MTJs formed by sandwiching a ferromagnetic (FM) monolayer CrI₃ or non-magnetic monolayer ScI₃ barrier between two vdW FM Fe₃GeTe₂ electrodes, respectively. It is found that two vdW MTJs possess strong perpendicular magnetic anisotropy. Moreover, due to no barrier for majority-spin transmission within half-metallic CrI₃ barrier and the difference between majority- and minority-spin conduction channels of the Fe₃GeTe₂ electrode, a high TMR ratio of about 3100% is achieved in vdW MTJs based on the Fe₃GeTe₂/CrI₃/Fe₃GeTe₂ vdW heterostructure. In contrast, a smaller TMR ratio of about 1200% is produced in vdW MTJs based on the Fe₃GeTe₂/ScI₃/Fe₃GeTe₂ vdW heterostructure due to the strong suppression of ScI₃ for majority-spin transmission in the case of the parallel state of magnetization of two FM electrodes. Our results provide a promising route for the design of vdW perpendicular MTJs with a high TMR ratio.

中文翻译：

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铁磁势垒引起范德华垂直磁隧道结中隧道磁阻的大幅增强

van der Waals (vdW) 固有磁体有望用于超越摩尔定律的器件小型化，用于未来节能纳米电子器件，并已成功用于构建高性能 vdW 磁隧道结 (vdW MTJ)。在这里，我们使用第一性原理计算，研究了通过将铁磁 (FM) 单层 CrI ₃或非磁性单层 ScI ₃势垒夹在两个 vdW FM 之间形成的 vdW MTJ 的磁各向异性、自旋相关输运和隧道磁阻 (TMR) 效应Fe ₃ GeTe ₂电极。发现两个 vdW MTJ 具有很强的垂直磁各向异性。此外，由于半金属 CrI 内的多数自旋传输没有障碍₃势垒以及 Fe ₃ GeTe ₂电极的多数和少数自旋传导通道之间的差异，在基于 Fe ₃ GeTe ₂ /CrI ₃ /Fe ₃ GeTe _{2 的}vdW MTJ 中实现了约 3100% 的高 TMR 比vdW 异质结构。相比之下，由于 ScI ₃的强烈抑制，基于 Fe ₃ GeTe ₂ /ScI ₃ /Fe ₃ GeTe ₂ vdW 异质结构的vdW MTJ 产生了较小的 TMR 比，约为 1200%用于在两个 FM 电极磁化平行状态下的多数自旋传输。我们的结果为设计具有高 TMR 比的 vdW 垂直 MTJ 提供了有希望的途径。