Generation of terahertz waves by a current in magnetic junctions

Gulyaev, Yu. V.; Zilberman, P. E.; Михайлов, Г. М.; Chigarev, S. G.

doi:10.1134/s0021364013240089

Cited by 23 publications

(16 citation statements)

References 20 publications

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“…One of the fundamental technical problems of the modern microwave/terahertz technology is the development of compact and reliable generators and receivers of coherent electromagnetic signals in the 0.1-10 THz frequency range [1][2][3]. The THz frequency range has a great potential for applications in medical imaging, security, material characterization, communications, control of technological processes, etc.…”

Section: Introductionmentioning

confidence: 99%

Terahertz-Frequency Spin Hall Auto-oscillator Based on a Canted Antiferromagnet

et al. 2017

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We propose a design of a THz-frequency signal generator based on a layered structure consisting of a current-driven platinum (Pt) layer and a layer of an antiferromagnet (AFM) with easy-plane anisotropy, where the magnetization vectors of the AFM sublattices are canted inside the easy plane by the Dzyaloshinskii-Moriya interaction (DMI). The DC electric current flowing in the Pt layer creates, due to the spin-Hall effect, a perpendicular spin current that, being injected in the AFM layer, tilts the DMI-canted AFM sublattices out of the easy plane, thus exposing them to the action of a strong internal exchange magnetic field of the AFM. The sublattice magnetizations, along with the small net magnetization vector mDMI of the canted AFM, start to rotate about the hard anisotropy axis of the AFM with the THz frequency proportional to the injected spin current and the AFM exchange field. The rotation of the small net magnetization mDMI results in the THzfrequency dipolar radiation that can be directly received by an adjacent (e.g. dielectric) resonator. We demonstrate theoretically that the radiation frequencies in the range f = 0.05 − 2 THz are possible at the experimentally reachable magnitudes of the driving current density, and evaluate the power of the signal radiated into different types of resonators, showing that this power increases with the increase of frequency f , and that it could exceed 1 µW at f ∼ 0.5 THz for a typical dielectric resonator of the electric permittivity ε ∼ 10 and quality factor Q ∼ 750.

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Section: Introductionmentioning

confidence: 99%

Terahertz-Frequency Spin Hall Auto-oscillator Based on a Canted Antiferromagnet

et al. 2017

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“…An absence of compact and reliable generators and receivers of coherent signals in the frequency range 0.1–10 THz has been identified as a fundamental physical and technological problem 1 2 3 . The existing approaches to THz-frequency generation, including superconductor Josephson junctions (JJ) 4 , free electron lasers 5 , and quantum cascades 6 require complex setups, which limit wide use of these devices.…”

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confidence: 99%

Antiferromagnetic THz-frequency Josephson-like Oscillator Driven by Spin Current

Khymyn

Lisenkov

Tiberkevich

et al. 2017

Sci Rep

265

237

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The development of compact and tunable room temperature sources of coherent THz-frequency signals would open a way for numerous new applications. The existing approaches to THz-frequency generation based on superconductor Josephson junctions (JJ), free electron lasers, and quantum cascades require cryogenic temperatures or/and complex setups, preventing the miniaturization and wide use of these devices. We demonstrate theoretically that a bi-layer of a heavy metal (Pt) and a bi-axial antiferromagnetic (AFM) dielectric (NiO) can be a source of a coherent THz signal. A spin-current flowing from a DC-current-driven Pt layer and polarized along the hard AFM anisotropy axis excites a non-uniform in time precession of magnetizations sublattices in the AFM, due to the presence of a weak easy-plane AFM anisotropy. The frequency of the AFM oscillations varies in the range of 0.1–2.0 THz with the driving current in the Pt layer from 108 A/cm2 to 109 A/cm2. The THz-frequency signal from the AFM with the amplitude exceeding 1 V/cm is picked up by the inverse spin-Hall effect in Pt. The operation of a room-temperature AFM THz-frequency oscillator is similar to that of a cryogenic JJ oscillator, with the energy of the easy-plane magnetic anisotropy playing the role of the Josephson energy.

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“…Similarly, Gulayev et al reported radiation from large contacts (>10 μm in diameter) between a ferromagnetic rod and a second ferromagnetic film [15][16][17] or an antiferromagnetic FeMn layer [18,19] observed in bolometric measurements using a Golay cell without intrinsic spectral resolution. Although they showed that the source of radiation is partially non-thermal [19][20][21][22], it is not demonstrably associated to the above named mechanism. As it stands, there is currently no unambiguous proof of optical spinflip radiation emitted from a magnetic hetero-junction with spectral resolution in the GHz or THz range.…”

Section: Introductionmentioning

confidence: 93%

“…For example Korenivski and coworkers showed non-specific emission of radiation from arrays of FePt/Cu point contacts using an integrating bolometric detector [10,14]. Similarly, Gulayev et al reported radiation from large contacts (>10 μm in diameter) between a ferromagnetic rod and a second ferromagnetic film [15][16][17] or an antiferromagnetic FeMn layer [18,19] observed in bolometric measurements using a Golay cell without intrinsic spectral resolution. Although they showed that the source of radiation is partially non-thermal [19][20][21][22], it is not demonstrably associated to the above named mechanism.…”

Section: Introductionmentioning

confidence: 99%

Microwave-induced direct spin-flip transitions in mesoscopic Pd/Co heterojunctions

et al. 2016

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We experimentally investigate the effect of resonant microwave absorption on the magneto-conductance of tunable Co/Pd point contacts. At the interface a non-equilibrium spin accumulation is created via microwave absorption and can be probed via point contact spectroscopy. We interpret the results as a signature of direct spin-flip excitations in Zeeman-split spin-subbands within the Pd normal metal part of the junction. The inverse effect, which is associated with the emission of a microwave photon in a ferromagnet/normal metal point contact, can also be detected via its unique signature in transport spectroscopy.

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Generation of terahertz waves by a current in magnetic junctions

Cited by 23 publications

References 20 publications

Terahertz-Frequency Spin Hall Auto-oscillator Based on a Canted Antiferromagnet

Terahertz-Frequency Spin Hall Auto-oscillator Based on a Canted Antiferromagnet

Antiferromagnetic THz-frequency Josephson-like Oscillator Driven by Spin Current

Microwave-induced direct spin-flip transitions in mesoscopic Pd/Co heterojunctions

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