Realization of a Spin-Wave Switch Based on the Spin-Transfer-Torque Effect

Meyer, T.; Brächer, Thomas; Heussner, Frank; Serga, Alexander A.; Naganuma, Hiroshi; Mukaiyama, Koki; Oogane, Mikihiko; Ando, Yasuo; Hillebrands, B.; Pirro, Philipp

doi:10.1109/lmag.2018.2803737

Cited by 8 publications

(8 citation statements)

References 31 publications

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“…This can e.g. be realized using inductive antennas, 145,166,[369][370][371][372] but also STT, 373 VCMA, 281,356 or magnetoelectric effects, 374,375 which intrinsically support the coupling to the longitudinal component of the magnetization. The similarity between transducers and amplifiers has the advantage that these components do not require very different integration schemes to be embedded in the same circuit and chip.…”

Section: F Spin-wave Amplifiers and Repeatersmentioning

confidence: 99%

Introduction to Spin Wave Computing

Mahmoud¹,

Ciubotaru²,

Vanderveken³

et al. 2021

Preprint

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This paper provides a tutorial overview over recent vigorous efforts to develop computing systems based on spin waves instead of charges and voltages. Spin-wave computing can be considered as a subfield of spintronics, which uses magnetic excitations for computation and memory applications. The tutorial combines backgrounds in spin-wave and device physics as well as circuit engineering to create synergies between the physics and electrical engineering communities to advance the field towards practical spin-wave circuits. After an introduction to magnetic interactions and spin-wave physics, all relevant basic aspects of spin-wave computing and individual spin-wave devices are reviewed. The focus is on spin-wave majority gates as they are the most prominently pursued device concept. Subsequently, we discuss the current status and the challenges to combine spin-wave gates and obtain circuits and ultimately computing systems, considering essential aspects such as gate interconnection, logic level restoration, input-output consistency, and fan-out achievement. We argue that spin-wave circuits need to be embedded in conventional CMOS circuits to obtain complete functional hybrid computing systems. The state of the art of benchmarking such hybrid spin-wave--CMOS systems is reviewed and the current challenges to realize such systems are discussed. The benchmark indicates that hybrid spin-wave--CMOS systems promise ultralow-power operation and may ultimately outperform conventional CMOS circuits in terms of the power-delay-area product. Current challenges to achieve this goal include low-power signal restoration in spin-wave circuits as well as efficient spin-wave transducers.

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Section: F Spin-wave Amplifiers and Repeatersmentioning

confidence: 99%

Introduction to Spin Wave Computing

Mahmoud¹,

Ciubotaru²,

Vanderveken³

et al. 2021

Preprint

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“…However, for small negative applied currents and for positive applied charge currents, the noise level might influence the inverse µBLS intensity. In particular, the decrease of the inverse µBLS intensity for currents above 20 mA is mainly caused due to an enhanced thermal magnon density caused by an increased sample temperature due to Joule heating as demonstrated in 30 . Since this influence of the thermal magnon density is not caused via the SHE-STT effect, this influence needs also to be taken into account as an additional current-dependent noise level.…”

mentioning

confidence: 94%

“…For the sake of completeness, it should be noted that also for currents below j Th , the spin-wave intensity shows a slight increase over time during the pulse duration. This is caused, e.g., due to an increasing magnon density caused by an increased temperature due to Joule heating 30 . However, in this case, I µBLS does not diverge in the beginning of the pulse but always show a saturationlike behavior.…”

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confidence: 99%

Characterization of spin-transfer-torque effect induced magnetization dynamics driven by short current pulses

Meyer

Brächer

Heussner

et al. 2018

Applied Physics Letters

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We present a time-resolved study of the magnetization dynamics in a microstructured Cr|Heusler|Pt waveguide driven by the Spin-Hall-Effect and the Spin-Transfer-Torque effect via short current pulses. In particular, we focus on the determination of the threshold current at which the spin-wave damping is compensated. We have developed a novel method based on the temporal evolution of the magnon density at the beginning of an applied current pulse at which the magnon density deviates from the thermal level. Since this method does not depend on the signal-to-noise ratio, it allows for a robust and reliable determination of the threshold current which is important for the characterization of any future application based on the Spin-Transfer-Torque effect.In the last years, the field of magnon spintronics 1 has attracted prominent interest since it offers great potential to realize future logic devices. In this field, currents of magnons, the quanta of spin-waves, are used to transport and process information. Recently, a set of prototype devices has been realized such as, e.g., the magnonic majority gate 2,3 , in which the logic state of the output signal is determined by the majority of the input states. Other works on magnon based devices such as the magnon transistor 4 , the spin-wave multiplexer 5 , domain walls as spinwave nanochannels 6 , graded-index magnonics 7 or a signal splitter based on caustic-like spin-wave beams 8 pave the way towards a controlled spin-wave transfer in magnonic networks.However, the application of these devices is limited by the finite magnon lifetime and, hence, the limited magnon propagation length determined by the Gilbert damping 9 . Thus, an efficient amplification of spin-waves or a control of the effective damping is inevitable. The latter can be achieved by employing the Spin-TransferTorque effect (STT) 10 . This effect yields an additional torque on the magnetization which can be co-aligned with the Gilbert damping torque resulting in an effective spin-wave damping given by the interplay of the Gilbert damping and the STT effect. This led, e.g., to the development of spin-torque nano-oscillators based on point-contacts which allow to generate oscillations in the GHz-range by DC currents 11,12 . Furthermore, in combination with the Spin-Hall-Effect (SHE) 13 to convert a charge current into a spin current in a normal metal, the SHE-STT effect allows for the control of the effective spin-wave damping also in spatially extended magnonic devices [14][15][16][17][18][19] . To achieve large SHE-STT induced effects with minimal current densities, the use of new materials with a low spin-wave damping, such as cobalt-based Heusler compounds 20 , is very promising. Using the SHE, e.g. in a Pt layer adjacent to a cobalt-based Heusler compound, the SHE-STT effect offers a powerful link to combine magnonics with CMOS technologies.Up to now, most of the reported studies on the manipulation of spin-waves in a magnonic waveguide via the SHE-STT effect only use static DC currents or quasi-DC p...

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“…At the same time, spin waves 25 and their corresponding quasi-particles, magnons [26][27][28] , have been employed in many prototype devices such as in a magnon transistor 29 , in spin-wave majority gates [30][31][32][33][34] , and in many others [35][36][37][38][39][40] . In this context, non-reciprocal spinwave propagation as a consequence of DMI might also constitute an interesting tool to boost the capabilities of spin-wave logic devices 41 .…”

Section: Introductionmentioning

confidence: 99%

Heisenberg Exchange and Dzyaloshinskii-Moriya Interaction in Ultrathin CoFeB Single and Multilayers

Böttcher¹,

Lee²,

Heussner³

et al. 2020

Preprint

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We present results of the analysis of Brillouin Light Scattering (BLS) measurements of spin waves performed on ultrathin single and multirepeat CoFeB layers with adjacent heavy metal layers. From a detailed study of the spin-wave dispersion relation, we independently extract the Heisenberg exchange interaction (also referred to as symmetric exchange interaction), the Dzyaloshinskii-Moriya interaction (DMI, also referred to as antisymmetric exchange interaction), and the anisotropy field. We find a large DMI in CoFeB thin films adjacent to a Pt layer and nearly vanishing DMI for CoFeB films adjacent to a W layer. Furthermore, the residual influence of the dipolar interaction on the dispersion relation and on the evaluation of the Heisenberg exchange parameter is demonstrated. In addition, an experimental analysis of the DMI on the spin-wave lifetime is presented. All these parameters play a crucial role in designing skyrmionic or spin-orbitronic devices.

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Realization of a Spin-Wave Switch Based on the Spin-Transfer-Torque Effect

Cited by 8 publications

References 31 publications

Introduction to Spin Wave Computing

Introduction to Spin Wave Computing

Characterization of spin-transfer-torque effect induced magnetization dynamics driven by short current pulses

Heisenberg Exchange and Dzyaloshinskii-Moriya Interaction in Ultrathin CoFeB Single and Multilayers

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