Abstract
Magnetic tunnel junction based on the CoFeB/MgO/CoFeB structures is of great interest due to its application in the spin-transfer-torque magnetic random access memory (STT-MRAM). Large interfacial perpendicular magnetic anisotropy (PMA) is required to achieve high thermal stability. Here, we use the first-principles calculations to investigate the magnetic anisotropy energy (MAE) of the MgO/CoFe/capping layer structures, where the capping materials include 5d metals Hf, Ta, Re, Os, Ir, Pt, and Au and 6p metals Tl, Pb, and Bi. We demonstrate that it is feasible to enhance PMA by using proper capping materials. Relatively large PMA is found in the structures with the capping materials of Hf, Ta, Os, Ir, and Pb. More importantly, the MgO/CoFe/Bi structure gives rise to giant PMA (6.09 mJ/m2), which is about three times larger than that of the MgO/CoFe/Ta structure. The origin of the MAE is elucidated by examining the contributions to MAE from each atomic layer and orbital. These findings provide a comprehensive understanding of the PMA and point towards the possibility to achieve the advanced-node STT-MRAM with high thermal stability.
| Original language | English (US) |
|---|---|
| Article number | 072403 |
| Journal | Applied Physics Letters |
| Volume | 110 |
| Issue number | 7 |
| DOIs | |
| State | Published - Feb 13 2017 |
Funding
The authors thank Albert Fert and Mairbek Chshiev for the fruitful discussions. S.Z.P. thanks the support by the China Scholarship Council (CSC). W.S.Z. thanks the support by the International Collaboration 111 Project B16001 from the Ministries of Education and Foreign Experts, the International Collaboration Project (2015DFE12880) from the Ministry of Science and Technology in China, the National Natural Science Foundation of China (Grant Nos. 61471015 and 61571023) and the Beijing Municipal of Science and Technology (Grant No. D15110300320000). H.X.Y. acknowledges the support by the ANR projects ULTRASKY and SOSPIN. K.L.W. acknowledges the support by the National Science Foundation under Award No. ECCS1611570 and the support by the Spins and Heat in Nanoscale Electronic Systems (SHINES), an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES) under Award No. DE-SC0012670. The work was partly supported by Inston Inc. through a Phase II Small Business Innovation Research award from the National Science Foundation.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)