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Effect of high annealing temperature on giant tunnel magnetoresistance ratio of CoFeB/MgO/CoFeB magnetic tunnel junctions

Jun Hayakawa·Shoji Ikeda·Young Min Lee·Fumihiro Matsukura·Hideo Ohno
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Abstract

We report tunnel magnetoresistance (TMR) ratios as high as 472% at room temperature and 804% at 5 K in pseudo-spin valve (SV) CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) annealed at 450oC, which is approaching the theoretically predicted value. By contrast, the TMR ratios for exchange-biased (EB) SV MTJs with a MnIr antiferromagnetic layer are found to drop when they are annealed at 450oC. Energy dispersive X-ray analysis shows that annealing at 450oC induces interdiffusion of Mn and Ru atoms into the MgO barrier and ferromagnetic layers in EB-SV MTJs. Mechanisms behind the different annealing behavior are discussed.

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Jun Hayakawa, Shoji Ikeda, Young Min Lee, Fumihiro Matsukura, Hideo Ohno. 2006-10-18. Effect of high annealing temperature on giant tunnel magnetoresistance ratio of CoFeB/MgO/CoFeB magnetic tunnel junctions. https://doi.org/10.1063/1.2402904

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