Inverse Tunnel Magnetocapacitance in Fe/Al-oxide/Fe(3)O(4).
Inverse Tunnel Magnetocapacitance in Fe/Al-oxide/Fe(3)O(4).
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DOI：
10.1038/s41598-017-02361-4
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发表时间：
2017-06-01
影响因子：
4.6
通讯作者：
Xiao G
中科院分区：
文献类型：
--
作者：
Kaiju H;Nagahama T;Sasaki S;Shimada T;Kitakami O;Misawa T;Fujioka M;Nishii J;Xiao G
磁电容效应广泛存在于多种材料和器件中，如多铁性材料和自旋电子器件，由于其有趣的物理性质和实际应用而受到人们的广泛关注。当电极中的自旋相互平行时，正常的MC效应表现出较高的电容，而当自旋反平行时，电容较低。本文首次报道了Fe/AlOx/Fe3O4磁性隧道结(MTJ)中的反向隧道磁电容(TMC)效应。逆TMC在室温下最高可达11.4%，并且逆TMC的偏置依赖关系揭示了自旋极化的稳健性。采用德拜-弗罗利希模型(结合张公式和抛物线势垒近似)和自旋相关的漂移-扩散模型，对整个外加频率范围和较宽的双极偏置区，得到了很好的理论和实验结果。此外，我们的理论计算还预测，在正负自旋极化分别为65%和−42%的MTJ中，反TMC效应可能达到150%。这些理论和实验结果为研究静态和动态自旋相关输运提供了新的视角。它们将为设备应用打开更广阔的机会，如磁性逻辑电路和多值存储设备。
Magnetocapacitance (MC) effect, observed in a wide range of materials and devices, such as multiferroic materials and spintronic devices, has received considerable attention due to its interesting physical properties and practical applications. A normal MC effect exhibits a higher capacitance when spins in the electrodes are parallel to each other and a lower capacitance when spins are antiparallel. Here we report an inverse tunnel magnetocapacitance (TMC) effect for the first time in Fe/AlOx/Fe3O4 magnetic tunnel junctions (MTJs). The inverse TMC reaches up to 11.4% at room temperature and the robustness of spin polarization is revealed in the bias dependence of the inverse TMC. Excellent agreement between theory and experiment is achieved for the entire applied frequency range and the wide bipolar bias regions using Debye-Fröhlich model (combined with the Zhang formula and parabolic barrier approximation) and spin-dependent drift-diffusion model. Furthermore, our theoretical calculations predict that the inverse TMC effect could potentially reach 150% in MTJs with a positive and negative spin polarization of 65% and −42%, respectively. These theoretical and experimental findings provide a new insight into both static and dynamic spin-dependent transports. They will open up broader opportunities for device applications, such as magnetic logic circuits and multi-valued memory devices.