近日，新加坡材料研究与工程研究所的Anjan Soumyanarayanan及其研究团队取得一项新进展。经过不懈努力，他们实现全电斯格明子磁隧道结。相关研究成果已于2024年3月20日在国际权威学术期刊《自然》上发表。

该研究团队成功在晶圆级别实现了纳米级手性磁隧道结（MTJ），这种结构能够容纳单一的斯格明子。通过运用一套先进的电多模态成像技术，研究人员发现MTJ中的斯格明子具有固定的极性，并且其大读出信号（相对于均匀磁化状态高达20-70%）直接反映了斯格明子的大小。这一创新结构利用互补成核机制，能在无磁场环境下稳定不同尺寸的斯格明子，从而实现三种非挥发性电态。尤为重要的是，该MTJ结构能够通过电信号写入和删除斯格明子，将其恢复到均匀状态，而且开关能量比现有技术水平低达1000倍。

在这里，施加的电压模拟了磁场的作用，相较于传统MTJ，它重塑了开关转变的能量学和动力学，实现了确定性的双向开关。该研究的堆栈平台不仅实现了大读出和高效开关，而且与斯格明子比特的横向操作兼容，为全电斯格明子设备架构提供了急需的支撑。其晶圆级别的可实现性为利用手性自旋纹理，在多比特存储器和非常规计算领域的应用提供了跳板。

据悉，拓扑旋转或自旋的“纹理”，如磁斯格明子，代表了最小的可实现的涌现磁实体。它们作为鲁棒的、纳米级的、可移动的比特，在可持续计算方面有着相当大的前景。长期以来，释放其潜力的一个障碍是缺乏一种设备，可以对单个自旋纹理进行确定的电子读出。

附：英文原文

Title: All-electrical skyrmionic magnetic tunnel junction

Author: Chen, Shaohai, Lourembam, James, Ho, Pin, Toh, Alexander K. J., Huang, Jifei, Chen, Xiaoye, Tan, Hang Khume, Yap, Sherry L. K., Lim, Royston J. J., Tan, Hui Ru, Suraj, T. S., Sim, May Inn, Toh, Yeow Teck, Lim, Idayu, Lim, Nelson C. B., Zhou, Jing, Chung, Hong Jing, Lim, Sze Ter, Soumyanarayanan, Anjan

Issue&Volume: 2024-03-20

Abstract: Topological whirls or ‘textures’ of spins such as magnetic skyrmions represent the smallest realizable emergent magnetic entities. They hold considerable promise as robust, nanometre-scale, mobile bits for sustainable computing. A longstanding roadblock to unleashing their potential is the absence of a device enabling deterministic electrical readout of individual spin textures. Here we present the wafer-scale realization of a nanoscale chiral magnetic tunnel junction (MTJ) hosting a single, ambient skyrmion. Using a suite of electrical and multimodal imaging techniques, we show that the MTJ nucleates skyrmions of fixed polarity, whose large readout signal—20–70% relative to uniformly magnetized states—corresponds directly to skyrmion size. The MTJ exploits complementary nucleation mechanisms to stabilize distinctly sized skyrmions at zero field, thereby realizing three non-volatile electrical states. Crucially, it can electrically write and delete skyrmions to both uniform states with switching energies 1,000 times lower than the state of the art. Here, the applied voltage emulates a magnetic field and, in contrast to conventional MTJs, it reshapes both the energetics and kinetics of the switching transition, enabling deterministic bidirectional switching. Our stack platform enables large readout and efficient switching, and is compatible with lateral manipulation of skyrmionic bits, providing the much-anticipated backbone for all-electrical skyrmionic device architectures. Its wafer-scale realizability provides a springboard to harness chiral spin textures for multibit memory and unconventional computing.

DOI: 10.1038/s41586-024-07131-7

Source: https://www.nature.com/articles/s41586-024-07131-7