Orbital-to-Spin Ratio of Dynamic Magnetization in Co/Pt
ORAL
Abstract
Recent theoretical work suggests that ferromagnets can generate orbital angular momentum through resonant magnetization dynamics involving both spin and orbital components [1,2]. X-ray magnetic circular dichroism measure the ratio of orbital-to-spin moment (μL/μS) in the dynamic magnetization of Co/Pt, a material combination known for strong spin-orbit coupling. We aim to explore whether orbital and spin magnetization dynamics can be distinct.
The dynamic X-ray transmission response of the FMR-driven Co magnetization precession at various photon energies was recorded, yielding the dynamic XMCD at Co L3,2 edges. By applying the XMCD sum rule analysis, we find (μL/μS)dynamic = 0.107 ± 0.002. This is about 5% more than (μL/μS)static = 0.102 ± 0.002 obtained from the static XMCD. The error bars for (μL/μS)dynamic and (μL/μS)static account for uncertainty due to background signal processing. The smaller (μL/μS)static compared to (μL/μS)dynamic could imply faster spin dissipation than orbital dissipation in Co interfaced with Pt. Our research contributes to understanding non-equilibrium orbital and spin angular moment, crucial for advanced "spin-orbitronic" devices.
[1] D. Go et al., arXiv:2309.14817 (2023).
[2] H. Hayashi et al., Nature Electronics, 1-7 (2024).
The dynamic X-ray transmission response of the FMR-driven Co magnetization precession at various photon energies was recorded, yielding the dynamic XMCD at Co L3,2 edges. By applying the XMCD sum rule analysis, we find (μL/μS)dynamic = 0.107 ± 0.002. This is about 5% more than (μL/μS)static = 0.102 ± 0.002 obtained from the static XMCD. The error bars for (μL/μS)dynamic and (μL/μS)static account for uncertainty due to background signal processing. The smaller (μL/μS)static compared to (μL/μS)dynamic could imply faster spin dissipation than orbital dissipation in Co interfaced with Pt. Our research contributes to understanding non-equilibrium orbital and spin angular moment, crucial for advanced "spin-orbitronic" devices.
[1] D. Go et al., arXiv:2309.14817 (2023).
[2] H. Hayashi et al., Nature Electronics, 1-7 (2024).
*We acknowledge the following funding bodies for their support:NSF Grant No. ECCS-2144333; AFOSR Grant No. FA9550-21-1-0365; NSF Grant No. ECCS-2236160; DoE BES Contract No. DE-AC02-05-CH11231.
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Presenters
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Omolara A Bakare
- Virginia Tech