Annealing temperature window for tunneling magnetoresistance and spin torque switching in CoFeB/MgO/CoFeB perpendicular magnetic tunnel junctions
Annealing temperature window for tunneling magnetoresistance and spin torque switching in CoFeB/MgO/CoFeB perpendicular magnetic tunnel junctions
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DOI：
10.1063/1.3662893
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发表时间：
2011-11-15
影响因子：
3.2
通讯作者：
Akhtar, M. A. K.
中科院分区：
文献类型：
--
作者：
Meng, H.;Sbiaa, R.;Akhtar, M. A. K.
研究了具有垂直磁各向异性（PMA）的CoFeB-MgO基磁隧道结的退火温度（T-a）和自由层厚度对磁性能和自旋传递转矩开关的依赖关系。退火过程是形成PMA的关键。随着T-a的增大，自由层和参考层的开关场先增强后减小，对应于两层PMA的改善和崩溃。但是，需要注意的是，在不同的T-a区，自由层的PMA和隧道磁电阻（TMR）都是最大的。自旋传递转矩研究指出，开关电流密度（J(c)）取决于PMA、自旋极化和饱和磁化的综合作用，它们都取决于T-a值。厚度依赖性研究表明，J(c)依赖于厚度和PMA的竞争结果。实现的最低临界开关电流密度为2.1 MA/cm(2)，在室温下TMR约为52%。vc2011美国物理研究所。(doi: 10.1063/1.3662893)
Annealing temperature (T-a) and free layer thickness dependencies of magnetic properties and spin-transfer torque switching were investigated in CoFeB-MgO based magnetic tunnel junctions with perpendicular magnetic anisotropy (PMA). Annealing process was found to be critical to buildup PMA. As T-a increases, switching field of free layer and reference layer is enhanced first then drops, corresponding to the improvement and collapse of PMA in both layers. However, it should be noted that PMA of free layer and the tunneling magnetoresistive (TMR) are maximized at different T-a zones. Spin transfer torque study pointed out that switching current density (J(c)) depends on the combined effects from PMA, spin polarization, and saturation magnetization, which all depend on T-a values. Thickness dependence study revealed that J(c) relies on the competing results of the thickness and PMA. The lowest critical switching current density achieved is 2.1 MA/cm(2), accompanied with a TMR around 52% at room temperature. VC 2011 American Institute of Physics. [doi:10.1063/1.3662893]