Accurate quantification of the spin–orbit torques(SOTs) is critical for the identification and applications of new spin-orbitronic effects. One of the most popular techniques to quantify the SOTs is the “switching a...Accurate quantification of the spin–orbit torques(SOTs) is critical for the identification and applications of new spin-orbitronic effects. One of the most popular techniques to quantify the SOTs is the “switching angle shift”, where the applied direct current is assumed to shift, via domain wall depinning during anti-domain expansion, the switching angle of a perpendicular magnetization in a linear proportional manner under a large rotating magnetic field. Here, we report that, for the most commonly employed perpendicular magnetization heterostructures in spintronics(e.g., those based on FeCoB, Co, and Co/Ni multilayers), the switching angle shift considerably misestimates the SOT within the domain wall depinning analysis of the slope of linear-in-current scaling and may also have a non-zero residual value at zero direct current. Our experiments and simulations unveil that the switching angle shift is most likely dominated by chiral asymmetric nucleation rather than expansion of anti-domains. The in-plane field from external magnets and current-induced SOTs lowers the perpendicular nucleation field and thus reduces the required switching angle, ultimately leading to an underestimation of SOTs by domain wall depinning analysis. These results have advanced our understanding of magnetization switching in spintronic devices.展开更多
Magnetoresistive random access memory(MRAM)is a promising non-volatile memory technology that can be utilized as an energy and space-efficient storage and computing solution,particularly in cache functions within circ...Magnetoresistive random access memory(MRAM)is a promising non-volatile memory technology that can be utilized as an energy and space-efficient storage and computing solution,particularly in cache functions within circuits.Although MRAM has achieved mass production,its manufacturing process still remains challenging,resulting in only a few semiconductor companies dominating its production.In this review,we delve into the materials,processes,and devices used in MRAM,focusing on both the widely adopted spin transfer torque MRAM and the next-generation spin-orbit torque MRAM.We provide an overview of their operational mechanisms and manufacturing technologies.Furthermore,we outline the major hurdles faced in MRAM manufacturing and propose potential solutions in detail.Then,the applications of MRAM in artificial intelligent hardware are introduced.Finally,we present an outlook on the future development and applications of MRAM.展开更多
近年来,由稀土元素和3d过渡金属构成的亚铁磁材料受到广泛的关注。亚铁磁材料既具有同铁磁材料一样的净余磁矩,又有反铁磁材料的超快动力学特征,这些性质使其成为自旋电子学领域的研究热点之一。在本工作中,采用磁控溅射的方法制备了亚...近年来,由稀土元素和3d过渡金属构成的亚铁磁材料受到广泛的关注。亚铁磁材料既具有同铁磁材料一样的净余磁矩,又有反铁磁材料的超快动力学特征,这些性质使其成为自旋电子学领域的研究热点之一。在本工作中,采用磁控溅射的方法制备了亚铁磁GdCo/Cu/Permalloy(Py)异质结,通过自旋-轨道铁磁共振(spin-orbit ferromagnetic resonance,ST-FMR)的方法研究了样品的磁化动力学和自旋传输特性,并分析了所制备样品的铁磁共振阻尼与自旋轨道矩效率。结果表明,所制备GdCo/Cu/Py异质结的自旋轨道矩(spin orbital torque,SOT)效率为−0.08,略低于重金属Pt的自旋霍尔角。同时铁磁共振阻尼分析也显示出GdCo/Cu/Py异质结中没有显著的自旋泵浦效应,导致这种现象的原因可能是界面处自旋传输的非互易性。研究证明亚铁磁GdCo薄膜不同于铁磁性材料的动态磁化特性,显示出其物理研究价值和实际应用潜力。展开更多
基金supported by the National Key Research and Development Program of China (Grant No.2022YFA1204000)partly by the National Natural Science Foundation of China (Grant Nos.12274405,12304155,and 12393831)the Beijing Natural Science Foundation (Grant No.Z230006)。
文摘Accurate quantification of the spin–orbit torques(SOTs) is critical for the identification and applications of new spin-orbitronic effects. One of the most popular techniques to quantify the SOTs is the “switching angle shift”, where the applied direct current is assumed to shift, via domain wall depinning during anti-domain expansion, the switching angle of a perpendicular magnetization in a linear proportional manner under a large rotating magnetic field. Here, we report that, for the most commonly employed perpendicular magnetization heterostructures in spintronics(e.g., those based on FeCoB, Co, and Co/Ni multilayers), the switching angle shift considerably misestimates the SOT within the domain wall depinning analysis of the slope of linear-in-current scaling and may also have a non-zero residual value at zero direct current. Our experiments and simulations unveil that the switching angle shift is most likely dominated by chiral asymmetric nucleation rather than expansion of anti-domains. The in-plane field from external magnets and current-induced SOTs lowers the perpendicular nucleation field and thus reduces the required switching angle, ultimately leading to an underestimation of SOTs by domain wall depinning analysis. These results have advanced our understanding of magnetization switching in spintronic devices.
基金supported in part by the Youth Innovation Promotion Association of Chinese Academy of Sciences(CAS)under Grant 2020118Beijing Nova Program under Grant 20230484358Beijing Superstring Academy of Memory Technology:under Grant No.E2DF06X003。
文摘Magnetoresistive random access memory(MRAM)is a promising non-volatile memory technology that can be utilized as an energy and space-efficient storage and computing solution,particularly in cache functions within circuits.Although MRAM has achieved mass production,its manufacturing process still remains challenging,resulting in only a few semiconductor companies dominating its production.In this review,we delve into the materials,processes,and devices used in MRAM,focusing on both the widely adopted spin transfer torque MRAM and the next-generation spin-orbit torque MRAM.We provide an overview of their operational mechanisms and manufacturing technologies.Furthermore,we outline the major hurdles faced in MRAM manufacturing and propose potential solutions in detail.Then,the applications of MRAM in artificial intelligent hardware are introduced.Finally,we present an outlook on the future development and applications of MRAM.
文摘近年来,由稀土元素和3d过渡金属构成的亚铁磁材料受到广泛的关注。亚铁磁材料既具有同铁磁材料一样的净余磁矩,又有反铁磁材料的超快动力学特征,这些性质使其成为自旋电子学领域的研究热点之一。在本工作中,采用磁控溅射的方法制备了亚铁磁GdCo/Cu/Permalloy(Py)异质结,通过自旋-轨道铁磁共振(spin-orbit ferromagnetic resonance,ST-FMR)的方法研究了样品的磁化动力学和自旋传输特性,并分析了所制备样品的铁磁共振阻尼与自旋轨道矩效率。结果表明,所制备GdCo/Cu/Py异质结的自旋轨道矩(spin orbital torque,SOT)效率为−0.08,略低于重金属Pt的自旋霍尔角。同时铁磁共振阻尼分析也显示出GdCo/Cu/Py异质结中没有显著的自旋泵浦效应,导致这种现象的原因可能是界面处自旋传输的非互易性。研究证明亚铁磁GdCo薄膜不同于铁磁性材料的动态磁化特性,显示出其物理研究价值和实际应用潜力。
