Enhancement of tunneling magnetoresistance by inserting a diffusion barrier in L10-FePd perpendicular magnetic tunnel junctions

De Lin Zhang, Karl B. Schliep, Ryan J. Wu, P. Quarterman, Danielle Reifsnyder Hickey, Yang Lv, Xiaohui Chao, Hongshi Li, Jun Yang Chen, Zhengyang Zhao, Mahdi Jamali, K. Andre Mkhoyan, Jian Ping Wang

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We studied the tunnel magnetoresistance (TMR) of L10-FePd perpendicular magnetic tunnel junctions (p-MTJs) with an FePd free layer and an inserted diffusion barrier. The diffusion barriers studied here (Ta and W) were shown to enhance the TMR ratio of the p-MTJs formed using high-temperature annealing, which are necessary for the formation of high quality L10-FePd films and MgO barriers. The L10-FePd p-MTJ stack was developed with an FePd free layer with a stack of FePd/X/Co20Fe60B20, where X is the diffusion barrier, and patterned into micron-sized MTJ pillars. The addition of the diffusion barrier was found to greatly enhance the magneto-transport behavior of the L10-FePd p-MTJ pillars such that those without a diffusion barrier exhibited negligible TMR ratios (<1.0%), whereas those with a Ta (W) diffusion barrier exhibited TMR ratios of 8.0% (7.0%) at room temperature and 35.0% (46.0%) at 10 K after post-annealing at 350 °C. These results indicate that diffusion barriers could play a crucial role in realizing high TMR ratios in bulk p-MTJs such as those based on FePd and Mn-based perpendicular magnetic anisotropy materials for spintronic applications.

Original languageEnglish (US)
Article number152401
JournalApplied Physics Letters
Issue number15
StatePublished - Apr 9 2018


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