Terahertz Radiation by Subpicosecond Magnetization Modulation in the Ferrimagnet LiFe<sub>5</sub>O<sub>8</sub>

Kinoshita, Yoshiki; Kida, N.; Sotome, M.; Miyamoto, T.; Iguchi, Y.; Okamoto, Hiroshi

doi:10.1021/acsphotonics.6b00272

Cited by 16 publications

(6 citation statements)

References 37 publications

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“…Figure 2 1mm-thick ZnTe crystal. By using terahertz radiation imaging [22][23][24][25][26], we confirmed that the BiTeBr crystal used in the present study has a polar single-domain structure. The result of the domain imaging is reported in the Supplemental Material [27].…”

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confidence: 75%

Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor

et al. 2018

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The spin-splitting energy bands induced by the relativistic spin-orbit interaction in solids provide a new opportunity to manipulate the spin-polarized electrons on the subpicosecond time scale. Here, we report one such example in a bulk Rashba-type polar semiconductor BiTeBr. Strong terahertz electromagnetic waves are emitted after the resonant excitation of the interband transition between the Rashba-type spin-splitting energy bands with a femtosecond laser pulse circularly polarized. The phase of the emitted terahertz waves is reversed by switching the circular polarization. This suggests that the observed terahertz radiation originates from the subpicosecond spin-polarized photocurrents, which are generated by the asymmetric depopulation of the Dirac state.Our result provides a new way for the current-induced terahertz radiation and its phase control by the circular polarization of incident light without external electric fields.

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confidence: 75%

Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor

et al. 2018

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“…This effect of the ringing can be seen in several publications displaying the THz signal in the time and frequency domains. [25][26][27][28] The peak-to-peak amplitude of the THz signal (E THz ) in time-domain is measured for all CFA/Pt STEs and used as the dependent variable in Equation ( 3) with the CFA thickness as an independent variable. The explanation of Equation ( 3) is given in the following section.…”

Section: Resultsmentioning

confidence: 99%

Co₂FeAl Full Heusler Compound Based Spintronic Terahertz Emitter

Gupta

Husain

Kumar

et al. 2021

Advanced Optical Materials

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To achieve a large terahertz (THz) amplitude from a spintronic THz emitter (STE), materials with 100% spin polarisation such as Co‐based Heusler compounds as ferromagnetic layer are required. However, these compounds are known to loose their half‐metallicity in the ultrathin film regime, as it is difficult to achieve L21 ordering, which has become a bottleneck for the film growth. Here, the successful deposition using room temperature DC sputtering of the L21 and B2 ordered phases of the Co2FeAl full Heusler compound is reported. Co2FeAl is used as ferromagnetic layer together with highly orientated Pt as nonferromagnetic layer in the Co2FeAl/Pt STE, where an MgO (10 nm) seed layer plays an important role to achieve the L21 and B2 ordering of Co2FeAl. The THz generation in the Co2FeAl/Pt STE is presented, which has a bandwidth of 0.2–4 THz. The THz electric field amplitude is optimized with respect to thickness, orientation, and growth parameters using a thickness dependent model considering the optically induced spin current, superdiffusive spin current, inverse spin Hall effect, and the THz attenuation in the layers. This study, based on the full Heusler Co2FeAl compound opens up a plethora of possibilities in STE research involving full Heusler compounds.

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“…Some additional properties such as strong Dzyaloshinskii-Moriya interaction lead to proposals for novel magnonic devices based on relativistic band engineering of LiFe crystals 25 . Besides microwave applications, the material is used for coatings of anodes for lithium ion batteries 26 , Terrahertz devices 27 and gas sensing 28 .…”

Section: Introductionmentioning

confidence: 99%

Cavity magnon polaritons with lithium ferrite and three-dimensional microwave resonators at millikelvin temperatures

et al. 2018

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Single crystal Lithium Ferrite (LiFe) spheres of sub-mm dimension are examined at mK temperatures, microwave frequencies and variable DC magnetic field, for use in hybrid quantum systems and condensed matter and fundamental physics experiments. Strong coupling regimes of the photon-magnon interaction (cavity magnon polariton quasi-particles) were observed with coupling strength of up to 250 MHz at 9.5 GHz (2.6%) with magnon linewidths of order 4 MHz (with potential improvement to sub-MHz values). We show that the photon-magnon coupling can be significantly improved and exceed that of the widely used Yttrium Iron Garnet crystal, due to the small unit cell of LiFe, allowing twice more spins per unit volume. Magnon mode softening was observed at low DC fields and combined with the normal Zeeman effect creates magnon spin wave modes that are insensitive to first order order magnetic field fluctuations. This effect is observed in the Kittel mode at 5.5 GHz (and another higher order mode at 6.5 GHz) with a DC magnetic field close to 0.19 Tesla. We show that if the cavity is tuned close to this frequency, the magnon polariton particles exhibit an enhanced range of strong coupling and insensitivity to magnetic field fluctuations with both first order and second order insensitivity to magnetic field as a function of frequency (double magic point clock transition), which could potentially be exploited in cavity QED experiments.

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Terahertz Radiation by Subpicosecond Magnetization Modulation in the Ferrimagnet LiFe₅O₈

Cited by 16 publications

References 37 publications

Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor

Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor

Co₂FeAl Full Heusler Compound Based Spintronic Terahertz Emitter

Cavity magnon polaritons with lithium ferrite and three-dimensional microwave resonators at millikelvin temperatures

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Terahertz Radiation by Subpicosecond Magnetization Modulation in the Ferrimagnet LiFe5O8

Cited by 16 publications

References 37 publications

Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor

Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor

Co2FeAl Full Heusler Compound Based Spintronic Terahertz Emitter

Cavity magnon polaritons with lithium ferrite and three-dimensional microwave resonators at millikelvin temperatures

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Terahertz Radiation by Subpicosecond Magnetization Modulation in the Ferrimagnet LiFe₅O₈

Co₂FeAl Full Heusler Compound Based Spintronic Terahertz Emitter