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

Bibliographical note

Funding Information:
This work was supported by C-SPIN, one of the six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA. Parts of this work were performed at the University of Minnesota Nanofabrication Center, which receives partial support from NSF through the NNIN program, and the Characterization Facility, which is a member of the NSF-funded Materials Research Facilities Network via the MRSEC program.

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© 2018 Author(s).

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