Laser-induced terahertz emission from layered synthetic magnets

Ogasawara, Yuma; Sasaki, Yuta; Iihama, Satoshi; Kamimaki, Akira; Suzuki, Kazuya; Mizukami, Shigemi

doi:10.35848/1882-0786/ab88c2

Cited by 22 publications

(24 citation statements)

References 36 publications

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“…On the other hand, we believe that the MTJ-based THz modulation demonstrated here can be integrated with the concept of spintronic THz emitters (such as W/FM/Pt [45] or FM/Ag/Bi [46,47] heterostructures). The noncollinear configuration of magnetizations in the synthetic spintronic structures will be useful for further designs of THz emitters with tunable amplitudes and polarizations [48,49].…”

Section: Resultsmentioning

confidence: 99%

Magnetic Modulation of Terahertz Waves via Spin-Polarized Electron Tunneling Based on Magnetic Tunnel Junctions

Jin

Zhang

et al. 2020

Phys. Rev. Applied

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© 2020 American Physical Society. Magnetic tunnel junctions (MTJs) are a key technology in modern spintronics because they are the basis of read-heads of modern hard disk drives, nonvolatile magnetic random access memories, and sensor applications. In this paper, we demonstrate that tunneling magnetoresistance can influence terahertz (THz) wave propagation through a MTJ. In particular, various magnetic configurations between parallel state and antiparallel state of the magnetizations of the ferromagnetic layers in the MTJ have the effect of changing the conductivity, making a functional modulation of the propagating THz electromagnetic fields. Operating in the THz frequency range, a maximal modulation depth of 60% is reached for the parallel state of the MTJ with a thickness of 77.45 nm, using a magnetic field as low as 30 mT. The THz conductivity spectrum of the MTJ is governed by spin-dependent electron tunneling. It is anticipated that the MTJ device and its tunability scheme will have many potential applications in THz magnetic modulators, filtering, and sensing.

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Section: Resultsmentioning

confidence: 99%

Magnetic Modulation of Terahertz Waves via Spin-Polarized Electron Tunneling Based on Magnetic Tunnel Junctions

Jin

Zhang

et al. 2020

Phys. Rev. Applied

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“…When focused, it resulted in longitudinal THz electric field amplitudes twice as much as that of the transverse signals achieved with linearly polarized THz radiation. Ogasawara et al [45] used synthetic magnets to manipulate the THz radiation. In particular, they prepared NM1(Ta)/CoFeB(FM)/Ir(NM2)/CoFeB(FM)/Ta(NM2) synthetic magnetic multilayers where the Ir spacer had different thicknesses.…”

Section: Stack Geometry Dependencementioning

confidence: 99%

THz spintronic emitters: a review on achievements and future challenges

2020

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The field of THz spintronics is a novel direction in the research field of nanomagnetism and spintronics that combines magnetism with optical physics and ultrafast photonics. The experimental scheme of the field involves the use of femtosecond laser pulses to trigger ultrafast spin and charge dynamics in thin films composed of ferromagnetic and nonmagnetic thin layers, where the nonmagnetic layer features a strong spin–orbit coupling. The technological and scientific key challenges of THz spintronic emitters are to increase their intensity and to shape the frequency bandwidth. To achieve the control of the source of the radiation, namely the transport of the ultrafast spin current is required. In this review, we address the generation, detection, efficiency and the future perspectives of THz emitters. We present the state-of-the-art of efficient emission in terms of materials, geometrical stack, interface quality and patterning. The impressive so far results hold the promise for new generation of THz physics based on spintronic emitters.

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“…During the last years, THz spintronic emitters have been heavily investigated aiming to obtain large signals and spectral bandwidths and to incorporate them into THz applications (Bull et al 2021, Papaioannou and Beigang 2021, Wu et al 2021. In particular, a wide range of material properties have been studied including: different material compositions of FM/NM layers with a variety of thicknesses (Qiu et al 2018, Seifert et al 2016, Wu et al 2017, Yang et al 2016, ferrimagnetic/NM structures (Fix et al 2020, Schneider et al 2018, 2019, Seifert et al 2017, and antiferromagnetic metal/NM (Ogasawara et al 2020). In addition, the impact of material interfaces were studied by inserting non-magnetic interlayer material such as Cu,Al, Ti, Au and ZnO layers in FM/X/NM trilayers (Gueckstock et al 2021, Hawecker et al 2021, Li et al 2018, Seifert et al 2018.…”

Section: Introductionmentioning

confidence: 99%

THz emission from Fe/Pt spintronic emitters with L1$_{0}$-FePt alloyed interface

Scheuer¹,

Ruhwedel²,

Karfaridis³

et al. 2022

Preprint

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Recent developments in nanomagnetism and spintronics have enabled the use of ultrafast spin physics for terahertz (THz) emission. Spintronic THz emitters, consisting of ferromagnetic FM / non-magnetic (NM) thin film heterostructures, have demonstrated impressive properties for the use in THz spectroscopy and have great potential in scientific and industrial applications. In this work, we focus on the impact of the FM/NM interface on the THz emission by investigating Fe/Pt bilayers with engineered interfaces. In particular, we intentionally modify the Fe/Pt interface by inserting an ordered L1 0 -FePt alloy interlayer. Subsequently, we establish that a Fe/L1 0 -FePt (2 nm)/Pt configuration is significantly superior to a Fe/Pt bilayer structure, regarding THz emission amplitude. The latter depends on the extent of alloying on either side of the interface. The unique trilayer structure opens new perspectives in terms of material choices for the next generation of spintronic THz emitters.

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Laser-induced terahertz emission from layered synthetic magnets

Cited by 22 publications

References 36 publications

Magnetic Modulation of Terahertz Waves via Spin-Polarized Electron Tunneling Based on Magnetic Tunnel Junctions

Magnetic Modulation of Terahertz Waves via Spin-Polarized Electron Tunneling Based on Magnetic Tunnel Junctions

THz spintronic emitters: a review on achievements and future challenges

THz emission from Fe/Pt spintronic emitters with L1$_{0}$-FePt alloyed interface

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