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Understanding voltage-controlled magnetic anisotropy effect at Co/oxide interface
Tomohiro Nozaki1, Jun Okabayashi2, Shingo Tamaru3
1Research Center for Emerging Computing Technologies (RCECT), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan. nozaki.tomohiro@aist.go.jp.
Scientific Reports
|June 30, 2023
Summary
Post-annealing enhances the voltage-controlled magnetic anisotropy (VCMA) effect in fcc-Co-(111) stacks. This study reveals that Pt diffusion at the Co/oxide interface increases orbital magnetic moments, boosting VCMA for spintronic devices.
Area of Science:
- Spintronics
- Materials Science
- Surface Science
Background:
- Voltage-controlled magnetic anisotropy (VCMA) is crucial for high-speed, low-power spintronic devices.
- Fcc-Co-(111)-based stacks show potential for large VCMA coefficients but are understudied.
- The mechanism behind enhanced VCMA in Pt/Ru/Co/CoO/TiOx structures after post-annealing was unclear.
Purpose of the Study:
- Investigate the origin of the VCMA effect at the Co/oxide interface in Pt/Ru/Co/CoO/TiOx structures.
- Understand the mechanism behind the observed increase in voltage-controlled coercivity (VCC) after post-annealing.
- Provide insights for designing fcc-Co-(111)-based stacks with enhanced VCMA.
Main Methods:
- Multiprobes analyses were conducted on the Pt/Ru/Co/CoO/TiOx structure before and after post-annealing.
- X-ray magnetic circular dichroism (XMCD) measurements were used to analyze magnetic properties.
- Structural characterization was performed to understand atomic arrangements and diffusion.
Main Results:
- Post-annealing significantly increased the voltage-controlled coercivity (VCC) of the Pt/Ru/Co/CoO/TiOx structure.
- XMCD measurements revealed an increase in the orbital magnetic moment at the Co/oxide interface after post-annealing.
- Evidence suggests Pt atom diffusion to the Co/oxide interface enhances interfacial properties.
Conclusions:
- Pt diffusion into the Co/oxide interface is proposed as the mechanism for enhanced VCMA.
- Increased interfacial orbital magnetic moment correlates with improved VCMA.
- The findings offer a design strategy for optimizing VCMA in fcc-Co-(111)-based spintronic applications.
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