Route toward high-speed nano-magnonics provided by pure spin currents

Divinskiy, B.; Demidov, V. E.; Demokritov, S. O.; Ринкевич, А. Б.; Urazhdin, Sergei

doi:10.1063/1.4972244

Cited by 22 publications

(18 citation statements)

References 32 publications

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“…Photonics and magnonics appeal to information technologies for their potential to overcome the problems inherent to modern electronics, such as dissipation of energy due to Ohmic losses. 1 − 4 The viability of magnonics depends on a successful increase of the frequency of magnon-based processing, which in traditional ferromagnetic materials (e.g., YIG) is restricted to the GHz regime. 5 − 7 The use of antiferromagnetic materials could be a solution because of their very high (terahertz) frequencies of spin resonances.…”

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confidence: 99%

Terahertz Magnon-Polaritons in TmFeO₃

Grishunin

Huisman

et al. 2018

ACS Photonics

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Magnon-polaritons are shown to play a dominant role in the propagation of terahertz (THz) waves through TmFeO3 orthoferrite, if the frequencies of the waves are in the vicinity of the quasi-antiferromagnetic spin resonance mode. Both time-domain THz transmission and emission spectroscopies reveal clear beatings between two modes with frequencies slightly above and slightly below this resonance, respectively. Rigorous modeling of the interaction between the spins of TmFeO3 and the THz light shows that the frequencies correspond to the upper and lower magnon-polariton branches. Our findings reveal the previously ignored importance of propagation effects and polaritons in such heavily debated areas as THz magnonics and THz spectroscopy of electromagnons. It also shows that future progress in these areas calls for an interdisciplinary approach at the interface between magnetism and photonics.

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confidence: 99%

Terahertz Magnon-Polaritons in TmFeO₃

Grishunin

Huisman

et al. 2018

ACS Photonics

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“…Further reduction of the critical current density should also be possible by yet higher PMA in yet thinner CoFeB. Second, their current tunability should allow these SHNO to rapidly switch between localized and propagating spin waves, effectively acting as tunable nanoscale sources of ultra-short SW pulses and wave packets 43 . Thirdly, the wave nature of the propagating SWs will now allow for experimental realizations of SOT driven spin wave computing 40,41 such as interference based majority gates.…”

Section: Discussionmentioning

confidence: 99%

“…As the current is increased, the non-linearity changes sign and the localized SWs exhibit smooth transition into propagating SWs at about 0.5 mA. It is hence possible to seamlessly turn on and off the localization, which will allow the generation of ultra-short SW pulses driven by the current alone, which is much faster than using external fields 43 .…”

Section: Introductionmentioning

confidence: 99%

Spin-orbit torque–driven propagating spin waves

et al. 2019

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Spin-orbit torque (SOT) can drive sustained spin wave (SW) auto-oscillations in a class of emerging microwave devices known as spin Hall nano-oscillators (SHNOs), which have highly non-linear properties governing robust mutual synchronization at frequencies directly amenable to high-speed neuromorphic computing. However, all demonstrations have relied on localized SW modes interacting through dipolar coupling and/or direct exchange. As nanomagnonics requires propagating SWs for data transfer, and additional computational functionality can be achieved using SW interference, SOT driven propagating SWs would be highly advantageous. Here, we demonstrate how perpendicular magnetic anisotropy can raise the frequency of SOT driven auto-oscillations in magnetic nano-constrictions well above the SW gap, resulting in the efficient generation of field and current tunable propagating SWs. Our demonstration greatly extends the functionality and design freedom of SHNOs enabling long range SOT driven SW propagation for nanomagnonics, SW logic, and neuromorphic computing, directly compatible with CMOS technology.

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“…The particular case of operation at 0.4 T allows for an interesting application where the current can be used to switch between localized and propagating SWs in the same devices. Ultimately, such SHNOs may deliver ultra-short SW pulses and wave packets [157]. The propagating waves could also be useful in synchronizing chains and arrays of SHNOs by optimizing the damping constant to allow for long-range propagation.…”

Section: Device Characterizationmentioning

confidence: 99%

Current Modulation of Nanoconstriction Spin-Hall Nano-Oscillators

et al. 2017

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This thesis explores the vibrant phenomena of spin Hall nano-oscillators (SHNOs); from wideband oscillation at the GHz range, through propagating spin-wave emission, to mutual synchronization in two-dimensional SHNO arrays, and tries to lay the foundation for a far-reaching SHNO technology, targeting magnonics, microwave signal generation, and neuromorphic computing. After a short introduction to the theoretical background in Chapter 1, in Chapter 2, ways of improving the spin transport properties between NiFe and Pt are explored: an 0.4 nm ultra-thin layer of Hf at the NiFe/Pt interface is found to reduce the threshold current by 20% as a result of the change in spin mixing conductance G Ö eff. Then, W/CoFeB/MgO stacks with perpendicular magnetic anisotropy (PMA) are used to demonstrate wide frequency tunability and sub-mA threshold currents in CMOS compatible SHNOs. By further increasing the PMA, the auto-oscillation frequency exceeds the ferromagnetic resonance (FMR) frequency, turning the SHNO into a propagating spin-wave emitter in which the propagation wave-vector is tunable with applied current and field. Finally, a GHz nano-scale SHNO modulated by an 80 MHz radio-frequency (RF) current is presented. The modulation needs no bulky microwave mixer, promising a compact modulator unit. Chapter 3 introduces two-dimensional SHNO arrays. Robust mutual synchronization is demonstrated in arrays accommodating up to 64 oscillators, achieving record high quality factors of 170,000 at an operating frequency of 10 GHz. Injection of two external microwave signals reproduces the two-dimensional synchronization maps used in neuromorphic vowel recognition. Chapter 4 emphasizes the importance of individual SHNO control in arrays. Gated SHNOs are demonstrated with substantial voltage tuning of the threshold current and the SHNO frequency. Voltage controlled mutual synchronization is also demonstrated. The MgO/AlO x /Si 3 N 4 gate is found to exhibit a memristive behavior governed by ion migration and acts as an embedded memory making each SHNO a complete non-volatile oscillator with integrated weights. The exciting nature of coupled non-volatile oscillator arrays controlled by electric field could lead to a paradigm shift in non-conventional computing. Chapter 5 discusses the implications of the demonstrated SHNO technology and how it may impact future applications.

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Route toward high-speed nano-magnonics provided by pure spin currents

Cited by 22 publications

References 32 publications

Terahertz Magnon-Polaritons in TmFeO₃

Terahertz Magnon-Polaritons in TmFeO₃

Spin-orbit torque–driven propagating spin waves

Current Modulation of Nanoconstriction Spin-Hall Nano-Oscillators

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Route toward high-speed nano-magnonics provided by pure spin currents

Cited by 22 publications

References 32 publications

Terahertz Magnon-Polaritons in TmFeO3

Terahertz Magnon-Polaritons in TmFeO3

Spin-orbit torque–driven propagating spin waves

Current Modulation of Nanoconstriction Spin-Hall Nano-Oscillators

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Product

Resources

About

Terahertz Magnon-Polaritons in TmFeO₃

Terahertz Magnon-Polaritons in TmFeO₃