Recent developments in magnetic tunnel junctions
Recent developments in magnetic tunnel junctions
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DOI：
10.1109/tmag.2003.815705
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发表时间：
2003-09
影响因子：
2.1
通讯作者：
X. Xiang;T. Zhu;F. Sheng;Ze Zhang;J. Xiao
中科院分区：
文献类型：
--
作者：
X. Xiang;T. Zhu;F. Sheng;Ze Zhang;J. Xiao
作者提出了磁隧穿结（MTJ）中的各种新现象。由于界面和势垒结构在决定物理现象中起着重要作用，他们采用了各种技术来表征这种结构。为了获得势垒信息，他们进行了电子全息研究，以原子分辨率直接显示能量分布。利用高分辨率透射电子显微镜、元素映射和飞行时间二次离子质谱法研究了不同层之间的相互扩散。利用这些结构信息，作者证明了MTJ中存在块状贡献，并确定了特征长度。此外，他们还观察到一个电导最小异常，这与通常观察到的零偏异常有很大不同。在具有Al/sub 2/O/sub 3/-ZrO势垒的MTJs中，在高达0.4 V的偏置下也观察到大的反向TMR。作者修改了Brinkman模型，加入了铁磁电极的电压依赖态密度，成功地解释了隧道磁电阻（TMR）、电导最小异常和反TMR的偏置依赖。
The authors present various new phenomena in magnetic tunneling junction (MTJ). Since the interface and barrier structure play a significant role in determining the physical phenomena, they have employed various techniques to characterize this structure. For obtaining the barrier information, they have performed electron holography studies which directly show the energy profile with atomic resolution. The interdiffusion between different layers has been studied using high-resolution transmission electron microscopy, elemental mapping, and time-of-flight secondary ion mass spectrometry. With this structural information, the authors showed the existence of bulklike contribution in MTJ and determined the characteristic length. In addition, they also observed a conductance minimum anomaly which is much different from the normally observed zero bias anomaly. Large inversed TMR has also been observed at bias as high as 0.4 V in MTJs with an Al/sub 2/O/sub 3/-ZrO barrier. The authors have modified the Brinkman model by incorporating the voltage dependent density of states of the ferromagnetic electrodes, which successfully explains the bias dependence of the tunneling magnetoresistance (TMR), conductance minimum anomaly, and inversed TMR.