Engineering Co2MnAlxSi1−x Heusler Compounds as a Model System to Correlate Spin Polarization, Intrinsic Gilbert Damping, and Ultrafast Demagnetization

Guillemard, Charles; Zhang, Wei; Malinowski, Grégory; Melo, Claudia de; Gorchon, Jon; Petit-Watelot, Sébastien; Ghanbaja, Jaâfar; Mangin, Stéphane; Fèvre, P. Le; Bertran, F.; Andrieu, S.

doi:10.1002/adma.201908357

Cited by 30 publications

(13 citation statements)

References 46 publications

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“…[16,17] Note that the demagnetization time (𝜏 M ) has been found to be related to the degree of spin polarization (P) by 𝜏 M ∝ (1 − P) −1 . [16,18] However, as opposed to CrO 2 , Fe 3 O 4 , and LaSrMnO 3 , the laser-induced demagnetizations of Co-based Heusler alloys Co 2 MnSi (𝜏 M ≈ 0.34 − 0.38 ps), Co 2 MnAl (𝜏 M ≈ 0.16 ps), Co 2 FeSi (𝜏 M ≈ 0.25 − 0.28 ps), and Co 2 FeAl (𝜏 M ≈ 0.2 ps) are much faster. [19][20][21][22] These ultrafast demagnetization time scales are similar with that of elemental 3d ferromagnets, such as Co (≈0.1 ps), Fe (≈0.10-0.30 ps), and Ni (≈0.60-0.80 ps).…”

Section: Introductionmentioning

confidence: 99%

Terahertz Spectral Signatures of Ultrafast Spin Transports in Ferromagnetic Heusler Alloy

Jin

Guo

Peng

et al. 2023

Advanced Physics Research

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Although the Co‐based Heusler compounds are predicted to be half‐metals, their sub‐picosecond demagnetization dynamics upon laser excitation show a transition‐metal‐like behavior. Any possible role of ultrafast nonlocal spin transport on the ultrafast demagnetization of half‐metallic Heusler compounds has only been inferred indirectly by time‐resolved magneto‐optical Kerr effect. Here, an ultrafast optically driven spin current traveling from Co2FeSi half metal into an adjacent Pt layer by using terahertz (THz) emission time‐domain spectroscopy (TDS) is demonstrated. By varying the magnetic field and excitation symmetry, the sizable THz generation from Co2FeSi/Pt stack arises from optically induced spin transport across the Co2FeSi/Pt interface in conjunction with spin‐to‐charge current conversion, via the inverse spin Hall effect (ISHE). The chemical ordering, interface roughness and magnetization of the samples become vital to engineer the THz emission properties. The amplitude of THz emission is comparable to that of CoFeB/Pt stack, thereby indicating Co2FeSi as an efficient ultrafast light‐driven spin current injector. Finally, by varying the pumping energy, the contributions are distinguished to the ultrafast spin current from thermalization and optical excitation of majority spins in Heusler alloy. This work illustrates THz emission TDS as a powerful tool to investigate the ultrafast spintronic properties of Heusler alloy/normal‐metal bilayers.

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Section: Introductionmentioning

confidence: 99%

Terahertz Spectral Signatures of Ultrafast Spin Transports in Ferromagnetic Heusler Alloy

Jin

Guo

Peng

et al. 2023

Advanced Physics Research

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“…[30] They have established an inverse relationship between fast remagnetization time (𝜏 r ) and 𝛼 due to the dominant contribution of magnon dynamics to the remagnetization process. Despite some efforts, [16][17][18]25,29,31,32] a systematic study on various effects of SOC of NM materials on the ultrafast demagnetization and fast remagnetization in NM/FM heterostructures has not been performed so far. In particular, the relationship among the 𝜏 m , 𝜏 r , and 𝛼 with the SOC strength of NM in NM/FM heterostructures has never been experimentally demonstrated or theoretically formulated.…”

Section: Introductionmentioning

confidence: 99%

Role of Spin–Orbit Coupling on Ultrafast Spin Dynamics in Nonmagnet/Ferromagnet Heterostructures

et al. 2022

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Spin-orbit coupling (SOC), the interaction between spin and orbital angular momentum of electrons, is imperative to control magnetic properties of nonmagnet (NM)/ferromagnet (FM) heterostructures and design energy-efficient and faster spin-based devices. Here, femtosecond pulsed laser-induced time-resolved magneto-optical Kerr effect magnetometry is employed to investigate magnetization dynamics in different NM/Co 20 Fe 60 B 20 heterostructures, where the NM layer varies as Cu, Ta, W, Pt, Ta/Ru/Ta, and Si/SiO 2 (no underlayer) that differ in SOC strength. It is observed that there is a systematic variation in ultrafast demagnetization time (𝝉 m ), fast remagnetization time (𝝉 r ), and Gilbert damping parameter (𝜶) with the SOC strength of the underlayer and an inverse relationship between 𝜶 and 𝝉 m , 𝝉 r is established due to the dominant contribution of spin current transport in ultrafast demagnetization and fast remagnetization processes. The spin pumping formalism estimates the effective spin-mixing conductance (G eff ) for different interfaces, which signifies that the high SOC strength of underlayers results in high G eff indicating more efficient transport of spin current through it. This study suggests that the SOC strength of the NM underlayer plays a significant role in controlling the ultrafast demagnetization process through interfacial spin current transport in a NM/FM heterostructure which can be beneficial for the development of ultrafast spintronics devices.

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“…It also presents a high saturation magnetization (1.26 T) 12,13 which allows operating with frequencies above the GHz range at remanence and could result in larger frequency band gaps in MC 14,15 . It also presents a high spin polarization (above 90% experimentally) [16][17][18][19][20][21] allowing interesting magnon spintronic devices [22][23][24] . However, to our knowledge, only few magnonics studies 10,11,[25][26][27][28] have been performed up to now with such materials and few Co-based Heusler alloy magnonic crystals exist in the literature 29,30 .…”

Section: Introductionmentioning

confidence: 99%

Influence of Ga+ milling on the spin waves modes in a Co2MnSi Heusler magnonic crystal

Mantion

Biziere

2022

Journal of Applied Physics

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Ferromagnetic resonance experiment was performed to study the magnonic modes of an antidot lattice nanopatterned in a sputtered Co2MnSi Heusler alloy thin film. The magnonic crystal was prepared with a Ga+ focused ion beam, and micromagnetic simulations were used to explain qualitatively and quantitatively the complex experimental spin waves spectrum. We demonstrate the necessity to consider the geometrical imperfections and the modification of the Co2MnSi magnetic parameters induced by the nanofabrication process to describe the evolution of the frequencies and spatial profiles of the principal experimental spin waves modes in the 0–300 mT magnetic field range. In particular, our model suggests that Ga+ milling induces a drastic decrease (between 80% and 90%) in the bulk Co2MnSi magnetic parameters. In addition, simulations reveal the presence of a diversity of localized and extended spin waves modes whose spatial profiles are closely related to the evolution of the magnetic state at equilibrium from a very non-collinear configuration up to a quasi-saturated state.

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Engineering Co₂MnAl_xSi₁₋_x Heusler Compounds as a Model System to Correlate Spin Polarization, Intrinsic Gilbert Damping, and Ultrafast Demagnetization

Cited by 30 publications

References 46 publications

Terahertz Spectral Signatures of Ultrafast Spin Transports in Ferromagnetic Heusler Alloy

Terahertz Spectral Signatures of Ultrafast Spin Transports in Ferromagnetic Heusler Alloy

Role of Spin–Orbit Coupling on Ultrafast Spin Dynamics in Nonmagnet/Ferromagnet Heterostructures

Influence of Ga+ milling on the spin waves modes in a Co2MnSi Heusler magnonic crystal

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