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中国物理学会期刊

应变调控双组分纳磁体辐射状磁涡旋极性可逆翻转

CSTR: 32037.14.aps.74.20250575

Strain-driven reversible switching of Radial vortex in a bicomponent nanomagnet

CSTR: 32037.14.aps.74.20250575
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  • 辐射状磁涡旋因具有拓扑稳定性及纳米级尺寸特性, 被视为磁电子器件中极具潜力的信息载体. 然而, 传统基于磁场或自旋极化电流的辐射状磁涡旋极性翻转方法面临能耗过高的问题. 针对这一挑战, 本文提出了一种基于多铁异质结构的新型无场调控方案, 该结构由双组分纳磁体(Terfenol-D/Ni)、重金属层及压电层复合构成. 其内在对称性破缺特性可有效打破辐射状磁涡旋的圆环对称性, 通过磁电耦合效应实现极性翻转的电压驱动调控. 基于MuMax3的电-力-磁多场耦合仿真表明, 当双组分材料比例 d _ \rm T D : d _ \rm Ni = 1:2 , 界面Dzyaloshinskii-Moriya相互作用(DMI)系数(D)在 1 . 2\; \rm m J / m ^ 2 — 1 . 9\; \rm m J / m ^2 范围内时, 系统稳定呈现辐射状磁涡旋态; 当 D=1.7\;\rm m J/m^2 时, 仅需90 mV电压脉冲即实现对双组分纳磁体辐射状磁涡旋极性翻转, 能耗较传统方法降低6个数量级(达aJ级别). 通过瞬态磁化动态模拟与能量演化分析, 研究揭示了该双组分多铁异质结构中辐射状磁涡旋极性翻转的物理机制: 应变作用下的双材料体系能量竞争驱动磁矩重构, 实现高效、超低能耗的极性翻转. 该方案为磁涡旋存储器的片上集成提供了新路径, 开创了非电流驱动型“电写”磁存储器件设计的新范式, 在低功耗自旋电子学领域具有重要应用价值.

     

    Radial magnetic vortices, characterized by their topological stability and nanoscale dimensions, are considered to be highly promising information carriers in magnetic electronic devices. However, traditional methods of reversing the polarity of radial magnetic vortices, which rely on magnetic fields or spin-polarized currents, encounter significant energy consumption problems. To address this challenge, this study proposes a novel field-free control scheme based on multiferroic heterostructures, consisting of a bicomponent nanomagnet (Terfenol-D/Ni), a heavy metal layer, and a piezoelectric layer. The intrinsic symmetry-breaking property of this structure effectively disrupts the circular symmetry of the radial magnetic vortex, which can make voltage-driven polarity reversal through magnetoelectric coupling effects. MuMax3-based multifield coupling simulations of electro-mechanical-magnetic interactions show that when the ratio of the bicomponent materials d _ \rm T D : d _ \rm Ni = 1 : 2 and the interfacial Dzyaloshinskii-Moriya interaction (DMI) coefficient (D) is in a range of 1 . 2\; \rm m J / m ^ 2 < D < 1 . 9\; \rm m J / m ^ 2 , the system stably presents a radial magnetic vortex state. Within this DMI coefficient range, when the thickness of the bicomponent nanomagnet is less than 4 nm, an appropriate radius can be found to ensure that the ground state of the bicomponent nanomagnet is a radial magnetic vortex state. Particularly, when the thickness t = 1 nm, the radius of the bicomponent nanomagnet can remain in the radial magnetic vortex state in a range of 50 ± 10 nm. In addition, this study also verifies that square and elliptical bicomponent nanomagnets each have a ground state of radial magnetic vortex. When D = 1.7\;\rm m J / m ^ 2 , only a 90 mV voltage pulse is required to achieve polarity reversal of the bicomponent nanomagnet, with a total energy consumption per bit Etotal of 5.6 aJ, which is six orders of magnitude lower than that from the traditional methods (reaching the aJ level). Through the simulation of transient magnetization dynamics and the analysis of energy evolution, this study reveals the physical mechanism of polarity reversal of radial magnetic vortices in this bicomponent multiferroic heterostructure: The energy competition in the bimaterial system driven by strain leads to the reconfiguration of magnetic moments, achieving the polarity reversal with efficient and ultra-low energy consumption. This scheme provides a new path for on-chip integration of magnetic vortex memory and opens up a new paradigm for designing non-current-driven “electric write” magnetic storage devices, which has significant application value in the field of low-power spintronics.

     

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