Enhanced spin-transfer torque in asymmetric superlattice magnetic tunnel junctions with engineered barrier profiles

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials Pub Date : 2025-06-06 DOI:10.1016/j.jmmm.2025.173276

Seyed Ali Hosseini Moradi , Nader Ghobadi , Sajad Esfandyari , Reza Daqiq

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引用次数: 0

Abstract

We systematically investigate charge current dynamics and spin-transfer torque (STT) in asymmetric superlattice magnetic tunnel junctions (MTJs) featuring distinct ferromagnetic electrodes: CoFeB and La_0.7Sr_0.3MnO₃. They incorporate both regular and engineered barrier-height profiles. The profiles include linear, Gaussian, Lorentzian, Pöschl-Teller, and anti-reflective designs. We use the non-equilibrium Green’s function formalism within the effective-mass tight-binding framework. STT is quantitatively evaluated under applied bias conditions. The study reveals that asymmetric MTJs exhibit marked enhancement in spin-transfer torque compared to symmetric counterparts. This improvement results from the interplay of asymmetric magnetization magnitudes and orientations. Custom barrier profiles optimize spin-polarized current transmission and angular momentum transfer. These findings deepen understanding of spin-dependent transport in complex MTJ architectures. These results highlight a promising pathway for advancing spintronic device performance, particularly in applications requiring efficient magnetization switching and low-power operation. The demonstrated approach offers a compelling strategy for designing next-generation spintronic components by leveraging structural asymmetry and barrier engineering to achieve superior STT efficiencies.

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非对称超晶格磁隧道结中增强的自旋传递转矩

我们系统地研究了具有不同铁磁电极：CoFeB和La0.7Sr0.3MnO3的非对称超晶格磁隧道结（MTJs）中的电荷电流动力学和自旋传递转矩（STT）。它们结合了常规和设计的屏障高度轮廓。轮廓包括线性、高斯、洛伦兹、Pöschl-Teller和抗反射设计。我们在有效质量紧密约束框架内使用非平衡格林函数形式。在施加偏置条件下，对STT进行定量评估。研究表明，非对称MTJs的自旋传递转矩明显高于对称MTJs。这种改进是不对称磁化强度和取向的相互作用的结果。自定义势垒剖面优化自旋极化电流传输和角动量传递。这些发现加深了对复杂MTJ结构中自旋相关输运的理解。这些结果强调了提高自旋电子器件性能的有希望的途径，特别是在需要高效磁化开关和低功耗操作的应用中。所展示的方法为设计下一代自旋电子元件提供了一种引人注目的策略，通过利用结构不对称和势垒工程来实现卓越的STT效率。

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来源期刊

Journal of Magnetism and Magnetic Materials 物理-材料科学：综合

CiteScore

5.30

自引率

11.10%

发文量

1149

审稿时长

59 days

期刊介绍： The Journal of Magnetism and Magnetic Materials provides an important forum for the disclosure and discussion of original contributions covering the whole spectrum of topics, from basic magnetism to the technology and applications of magnetic materials. The journal encourages greater interaction between the basic and applied sub-disciplines of magnetism with comprehensive review articles, in addition to full-length contributions. In addition, other categories of contributions are welcome, including Critical Focused issues, Current Perspectives and Outreach to the General Public. Main Categories: Full-length articles: Technically original research documents that report results of value to the communities that comprise the journal audience. The link between chemical, structural and microstructural properties on the one hand and magnetic properties on the other hand are encouraged. In addition to general topics covering all areas of magnetism and magnetic materials, the full-length articles also include three sub-sections, focusing on Nanomagnetism, Spintronics and Applications. The sub-section on Nanomagnetism contains articles on magnetic nanoparticles, nanowires, thin films, 2D materials and other nanoscale magnetic materials and their applications. The sub-section on Spintronics contains articles on magnetoresistance, magnetoimpedance, magneto-optical phenomena, Micro-Electro-Mechanical Systems (MEMS), and other topics related to spin current control and magneto-transport phenomena. The sub-section on Applications display papers that focus on applications of magnetic materials. The applications need to show a connection to magnetism. Review articles: Review articles organize, clarify, and summarize existing major works in the areas covered by the Journal and provide comprehensive citations to the full spectrum of relevant literature.