Ultrafast Spin Dynamics of Pt/Gd 19 (Co 0.8 Fe 0.2) 81 /Ta Heterostructure Investigated by Double-Pump Terahertz Emission Spectroscopy.
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| Title: | Ultrafast Spin Dynamics of Pt/Gd 19 (Co 0.8 Fe 0.2) 81 /Ta Heterostructure Investigated by Double-Pump Terahertz Emission Spectroscopy. |
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| Authors: | Li, Changwei1 (AUTHOR), Lu, Bo1,2 (AUTHOR), Yu, Nuoxi1 (AUTHOR), Li, Zhangshun1,2 (AUTHOR), Xu, Haoran1 (AUTHOR), Zhang, Huiping1,2 (AUTHOR) hpzhang@usst.edu.cn, Jin, Zuanming1,2 (AUTHOR) |
| Source: | Nanomaterials (2079-4991). Apr2026, Vol. 16 Issue 7, p390. 10p. |
| Subjects: | Demagnetization, Heterostructures, Magnetic relaxation, Spin-spin interactions, Terahertz technology, Terahertz spectroscopy, Electron-phonon interactions, Spintronics |
| Abstract: | Ultrafast spin dynamics is a core research focus for advancing ultrafast spintronic devices, yet its accurate quantitative probing remains a challenge with conventional time-resolved techniques. Herein, we employ double-pump optical pump–terahertz emission spectroscopy (OPTE) to investigate the ultrafast spin dynamics of a Pt/Gd19(Co0.8Fe0.2)81/Ta ferrimagnetic rare-earth–transition-metal heterostructure. Experimental measurements resolve a single-step ultrafast demagnetization process with a characteristic time of ~0.42 ± 0.02 ps, followed by two-stage magnetic recovery involving a fast relaxation and a slow relaxation process. The fast and slow recovery time constants show a distinct positive dependence on the control pump fluence, increasing from 2.49 ± 0.11 ps to 3.28 ± 0.03 ps and 57.36 ± 11.28 ps to 164.96 ± 1.61 ps, respectively, as the pump fluence rises from 0.80 to 1.19 mJ/cm2. The ~0.42 ps demagnetization timescale is consistent with that of 3d transition metals, indicating the transient magnetic response of the low-Gd-concentration heterostructure is dominated by the CoFe sublattice. Our findings validate that OPTE is an effective approach for the quantitative characterization of electron–lattice–spin coupling processes in spin-based heterostructures and provide critical experimental insights for controllable manipulation of ultrafast spin dynamics, laying a foundation for the design of ultrafast terahertz spintronic devices. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | Ultrafast spin dynamics is a core research focus for advancing ultrafast spintronic devices, yet its accurate quantitative probing remains a challenge with conventional time-resolved techniques. Herein, we employ double-pump optical pump–terahertz emission spectroscopy (OPTE) to investigate the ultrafast spin dynamics of a Pt/Gd19(Co0.8Fe0.2)81/Ta ferrimagnetic rare-earth–transition-metal heterostructure. Experimental measurements resolve a single-step ultrafast demagnetization process with a characteristic time of ~0.42 ± 0.02 ps, followed by two-stage magnetic recovery involving a fast relaxation and a slow relaxation process. The fast and slow recovery time constants show a distinct positive dependence on the control pump fluence, increasing from 2.49 ± 0.11 ps to 3.28 ± 0.03 ps and 57.36 ± 11.28 ps to 164.96 ± 1.61 ps, respectively, as the pump fluence rises from 0.80 to 1.19 mJ/cm2. The ~0.42 ps demagnetization timescale is consistent with that of 3d transition metals, indicating the transient magnetic response of the low-Gd-concentration heterostructure is dominated by the CoFe sublattice. Our findings validate that OPTE is an effective approach for the quantitative characterization of electron–lattice–spin coupling processes in spin-based heterostructures and provide critical experimental insights for controllable manipulation of ultrafast spin dynamics, laying a foundation for the design of ultrafast terahertz spintronic devices. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 20794991 |
| DOI: | 10.3390/nano16070390 |
