Interfacial electronic structure-modulated magnetic anisotropy in Ta/CoFeB/MgO/Ta multilayers

Journal Article · Mon Sep 01 00:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4894765· OSTI ID:22311022

Chen, Xi; Jiang, Shao Long; Yang, Guang; Liu, Yang; Teng, Jiao; Wang, Kai You ^[1]; Wu, Zheng Long ^[2]

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1. SKLSM, Institute of Semiconductors, CAS, P. O. Box 912, Beijing 100083 (China)
2. Analytical and Testing Center, Beijing Normal University, Beijing 100875 (China)

We have observed several unexpected phenomena when a trace amount of Fe atoms is deposited onto the CoFeB/MgO interface in Ta/CoFeB/MgO/Ta multilayers. With the nominal thickness of the introduced Fe atoms (t{sub Fe}) varying from 0 to 0.1 Å, the effective magnetic anisotropy energy (K{sub eff}) of annealed multilayers is remarkably enhanced from 1.28 × 10{sup 6 }erg/cm{sup 3} to 2.14 × 10{sup 6 }erg/cm{sup 3}. As t{sub Fe} further increasing, the K{sub eff} decreases and even becomes negative when t{sub Fe} > 1 Å, indicating the change from perpendicular magnetic anisotropy to in-plane magnetic anisotropy. The analysis by X-ray photoelectron spectrometer reveals that the Fe atoms at annealed CoFeB/MgO interface show different electronic structures as t{sub Fe} increasing, which combine with O atoms to form FeO{sub x} (x < 1), Fe{sub 2}O{sub 3}, and Fe{sub 3}O{sub 4}, respectively, leading to modulation of Fe 3d-O 2p orbital hybridization and thus the K{sub eff}. On the other hand, we find that the introduction of Fe atoms also helps to reduce the multilayers' magnetic damping.

• OSTI ID: 22311022
• Journal Information: Applied Physics Letters, Vol. 105, Issue 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
ANNEALING
ATOMS
BORON COMPOUNDS
COBALT COMPOUNDS
ELECTRONIC STRUCTURE
INTERFACES
IRON COMPOUNDS
IRON OXIDES
LAYERS
MAGNESIUM OXIDES
MAGNETIC PROPERTIES
MODULATION
TANTALUM
TERNARY ALLOY SYSTEMS
TRACE AMOUNTS
X-RAY PHOTOELECTRON SPECTROSCOPY