Title: Enhancement of voltage-controlled magnetic anisotropy through precise control of Mg insertion thickness at CoFeB|MgO interface

Abstract

We studied the impact of different insertion layers (Ta, Pt, and Mg) at the CoFeB|MgO interface on voltage-controlled magnetic anisotropy (VCMA) effect and other magnetic properties. Inserting a very thin Mg layer of 0.1–0.3 nm yielded a VCMA coefficient of 100 fJ/V-m, more than 3 times higher than the average values of around 30 fJ/V-m reported in Ta|CoFeB|MgO-based structures. Ta and Pt insertion layers also showed a small improvement, yielding VCMA coefficients around 40 fJ/V-m. Electrical, magnetic, and X-ray diffraction results reveal that a Mg insertion layer of around 1.2 nm gives rise to the highest perpendicular magnetic anisotropy, saturation magnetization, as well as the best CoFe and MgO crystallinity. Other Mg insertion thicknesses give rise to either under- or over-oxidation of the CoFe|MgO interface; a strong over-oxidation of the CoFe layer leads to the maximum VCMA effect. These results show that precise control over the Mg insertion thickness and CoFe oxidation level at the CoFeB|MgO interface is crucial for the development of electric-field-controlled perpendicular magnetic tunnel junctions with low write voltage.

Authors:

Li, Xiang  ^[1];

• Search DOE PAGES for author "Li, Xiang"
• Search DOE PAGES for ORCID "0000-0001-6457-583X"

Fitzell, Kevin ^[2]; Wu, Di ^[3]; Karaba, C. Ty ^[4]; Buditama, Abraham  ^[4];

• Search DOE PAGES for author "Buditama, Abraham"
• Search DOE PAGES for ORCID "0000-0002-1628-0559"

Yu, Guoqiang  ^[1];

• Search DOE PAGES for author "Yu, Guoqiang"
• Search DOE PAGES for ORCID "0000-0002-7439-6920"

Wong, Kin L. ^[1]; Altieri, Nicholas ^[4]; Grezes, Cecile  ^[1];

• Search DOE PAGES for author "Grezes, Cecile"
• Search DOE PAGES for ORCID "0000-0001-7808-6404"

Kioussis, Nicholas ^[5]; Tolbert, Sarah ^[4]; Zhang, Zongzhi ^[6]; Chang, Jane P. ^[2]; Khalili Amiri, Pedram ^[7]; Wang, Kang L. ^[1]

---

+ Show Author Affiliations

1. Univ. of California, Los Angeles, CA (United States). Dept. of Electrical Engineering
2. Univ. of California, Los Angeles, CA (United States). Dept. of Chemical and Biomolecular Engineering
3. Univ. of California, Los Angeles, CA (United States). Dept. of Electrical Engineering; Fudan Univ., Shanghai (China). Dept. of Optical Science and Engineering, Key Lab. of Micro and Nano Photonic Structures (Ministry of Education)
4. Univ. of California, Los Angeles, CA (United States). Dept. of Chemistry and Biochemistry
5. California State Univ. (CalState), Northridge, CA (United States). Dept. of Physics and Astronomy
6. Fudan Univ., Shanghai (China). Dept. of Optical Science and Engineering, Key Lab. of Micro and Nano Photonic Structures (Ministry of Education)
7. Univ. of California, Los Angeles, CA (United States). Dept. of Electrical Engineering; Inston, Inc., Los Angeles, CA (United States)

Publication Date:

Mon Jan 30 00:00:00 EST 2017

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Spins and Heat in Nanoscale Electronic Systems (SHINES)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1470343

Grant/Contract Number:  

SC0012670

Resource Type:

Accepted Manuscript

Journal Name:

Applied Physics Letters

Additional Journal Information:

Journal Volume: 110; Journal Issue: 5; Related Information: SHINES partners with University of California, Riverside (lead); Arizona State University; Colorado State University; Johns Hopkins University; University of California Irvine; University of California Los Angeles; University of Texas at Austin; Journal ID: ISSN 0003-6951

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; 42 ENGINEERING; phonons; thermal conductivity; thermoelectric; spin dynamics; spintronics