Investigation of magnetization dynamics in exchange-biased Antiferromagnetic/Ferromagnetic/Non-magnetic (AFM/FM/NM) systems with perpendicular magnetic anisotropy

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K23583
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0402:Nano/micro science, applied condensed matter physics, applied physics and engineering, and related fields
• Research Institution: Tohoku University
• Principal Investigator: NGUYEN THI VAN ANH 東北大学, 先端スピントロニクス研究開発センター, 助教 (20840101)
• Project Period (FY): 2019-08-30 – 2022-03-31
• Keywords: antiferromagnetic / magnetization dynamics / damping constant / exchange bias system / ferromagnetic resonance / PMA

Outline of Final Research Achievements

The control of magnetization using a voltage has attracted much attention because it has opened the way to realize the ultra-low power spintronic devices. By using Cr2O3 thin film, we also could achieve the voltage-induced magnetization switching in an adjacent ferromagnetic (FM) layer, thanks to the exchange coupling between Cr2O3 and FM. Since the dynamic magnetic properties are closely related to magnetization switching, a deep understanding on these properties is necessitated.
We focused on the investigation of the dynamic magnetic properties of Pt/FM/Cr2O3 systems using the ferromagnetic resonance technique. The results showed that the dynamic magnetic properties depends on both of the FM layer thickness and Pt layer thickness. This means that the dynamic magnetic properties of the Pt/FM/Cr2O3 system are strongly determined by the FM layer, and these properties could be correlated by the perpendicular magnetic anisotropy and the exchange coupling in the FM/Cr2O3 system.

Free Research Field

応用物理工学

Academic Significance and Societal Importance of the Research Achievements

So far the investigation of dynamic magnetic properties in exchange-coupled Cr2O3/FM/NM systems was lack. The investigation here would set more light in the origin of the voltage-induced magnetization switching, and contribute to the realization of ultra-low power spintronic devices using Cr2O3.