Authors
Yu-Chia Chen, Thomas Peterson, Qi Jia, Yifei Yang, Shuang Liang, Brandon R Zink, Yu Han Huang, Deyuan Lyu, Brahmdutta Dixit, Jian-Ping Wang
Published in
ACS nano. Apr 14, 2025. Epub Apr 14, 2025.
Abstract
Voltage-Controlled Magnetic Anisotropy (VCMA) effect is a promising strategy for reducing energy consumption in Magnetic Random-Access Memory (MRAM) for embedded applications. However, the low efficiency of VCMA poses challenges for CoFeB/MgO-based MRAM. Although significant VCMA coefficients have been predicted based on electron depletion (ED) in the orbital population model for Fe/MgO interfaces, experimental validation remains limited. Here, we demonstrate an effective and industry-compatible approach to achieving an electrical-field tunable interfacial perpendicular magnetic anisotropy (PMA) and an enhanced VCMA coefficient by synthesizing W-based metallic alloy underlayers with varying Pt concentrations, leveraging Pt's high work function and strong electronegativity. Compared with pure W control devices, the alloy with the highest Pt concentration achieves a VCMA enhancement approximately eight times greater. Additionally, significant electron depletion in the Fe 2p3/2 and 2p1/2 orbitals at the CoFeB/MgO interface is observed through binding energy shifts. High-resolution X-ray photoelectron spectroscopy (HR-XPS) confirms these shifts as increased binding energies, indicating reduced electron density at the interface. These findings suggest that VCMA efficiency in MRAM devices can be enhanced by controlling the Fermi surface at the CoFeB/MgO interface under thermal equilibrium.
PMID:
40228156
Bibliographic data and abstract were imported from PubMed on 15 Apr 2025.
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