230% room-temperature magnetoresistance in CoFeB/MgO/CoFeB magnetic tunnel junctions
230% room-temperature magnetoresistance in CoFeB/MgO/CoFeB magnetic tunnel junctions
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DOI：
10.1063/1.1871344
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发表时间：
2005-02-28
影响因子：
4
通讯作者：
Ando, K
中科院分区：
文献类型：
--
作者：
Djayaprawira, DD;Tsunekawa, K;Ando, K
在室温下（20 K时为294％），在自旋 - 阀型磁性隧道连接点（MTJ）中，使用在热氧化的SI底物上制造的MGO隧道屏障层，在室温下（20 K时为294％）的磁性比率高达230％。我们发现，将MGO屏障层与无定形COFEB铁磁电极夹在一起时，可以获得如此高的MR比率。微观结构分析表明，当Mgo层在无定形COFEB而不是在多晶型COFE上生长时，实现了具有（001）纤维质地的MGO层。由于在MTJ上没有具有结晶隧道屏障和无定形电极的理论研究，因此目前尚不清楚这项研究中观察到的巨大隧道MR效应的详细机制。然而，目前的工作对于实现高密度磁磁性随机访问存储器和对超高密度硬盘驱动器的读数至关重要。 （c）2005年美国物理研究所。
Magnetoresistance (MR) ratio up to 230% at room temperature (294% at 20 K) has been observed in spin-valve-type magnetic tunnel junctions (MTJs) using MgO tunnel barrier layer fabricated on thermally oxidized Si substrates. We found that such a high MR ratio can be obtained when the MgO barrier layer was sandwiched with amorphous CoFeB ferromagnetic electrodes. Microstructure analysis revealed that the MgO layer with (001) fiber texture was realized when the MgO layer was grown on amorphous CoFeB rather than on polycrystalline CoFe. Since there have been no theoretical studies on the MTJs with a crystalline tunnel barrier and amorphous electrodes, the detailed mechanism of the huge tunneling MR effect observed in this study is not clear at the present stage. Nevertheless, the present work is of paramount importance in realizing high-density magnetoresistive random access memory and read head for ultra high-density hard-disk drives into practical use. (C) 2005 American Institute of Physics.