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Current-driven magnetization switching in CoFeB/MgO/CoFeB magnetic tunnel junctions

Jun Hayakawa·Shoji Ikeda·Young Min Lee·Ryutaro Sasaki·Toshiyasu Meguro·Fumihiro Matsukura·Hiromasa Takahashi·Hideo Ohno
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Abstract

Current-driven magnetization switching in low-resistance Co40Fe40B20/MgO/Co40Fe40B20 magnetic tunnel junctions (MTJs) is reported. The critical-current densities Jc required for current-driven switching in samples annealed at 270C and 300C are found to be as low as 7.8 x 10^5 A/cm^2 and 8.8 x 10^5 A/cm^2 with accompanying tunnel magnetoresistance (TMR) ratios of 49% and 73 %, respectively. Further annealing of the samples at 350C increases TMR ratio to 160 %, while accompanying Jc increases to 2.5 x 10^6 A/cm^2. We attribute the low Jc to the high spin-polarization of tunnel current and small MsV product of the CoFeB single free layer, where Ms is the saturation magnetization and V the volume of the free layer.

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Jun Hayakawa, Shoji Ikeda, Young Min Lee, Ryutaro Sasaki, Toshiyasu Meguro, Fumihiro Matsukura, Hiromasa Takahashi, Hideo Ohno. 2005-10-20. Current-driven magnetization switching in CoFeB/MgO/CoFeB magnetic tunnel junctions. https://doi.org/10.1143/jjap.44.l1267

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