Current-Induced Control of Spin-Wave Attenuation

Seo, Soo Man; Lee, Kyung Jin; Yang, Hyunsoo; Ono, Teruo

doi:10.1103/physrevlett.102.147202

Cited by 108 publications

(86 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A high density of direct current (DC) that is spin polarized by passing through a ferromagnetic metallic nanowire has been proposed to compensate for SW damping via STT. However, the effect of SW amplification is small due to a small non-adiabatic STT, predicted and demonstrated to be less than 1% 13,14 . The search for more efficient STT materials has led to the investigation of metallic bilayer structures consisting of a magnetic layer and a nonmagnetic layer with strong spinorbit coupling (e.g., Pt [15][16][17][18] , Ta 19 , and W 20 ).…”

Section: Introductionmentioning

confidence: 99%

Control of propagating spin waves via spin transfer torque in a metallic bilayer waveguide

Birt

Pai

et al. 2014

Phys. Rev. B

View full text Add to dashboard Cite

We investigate the effect of a direct current on propagating spin waves in a CoFeB/Ta bilayer structure. Using the micro-Brillouin light scattering technique, we observe that the spin wave damping and amplitude may be attenuated or amplified depending on the direction of the current and the applied magnetic field. Our work suggests an effective approach for electrically controlling the propagation of spin waves in a magnetic waveguide and may be useful in a number of applications such as phase locked nano-oscillators and hybrid information processing devices.

show abstract

Section: Introductionmentioning

confidence: 99%

Control of propagating spin waves via spin transfer torque in a metallic bilayer waveguide

Birt

Pai

et al. 2014

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…This indicates that the microwave field creates a domain wall and reverses the magnetization direction of the wire via domain wall propagation prior to the injection of the voltage pulse to line B when the field is at H (nucleation of the wall by the microwave field is confirmed by monitoring the microwave field induced nucleation process in real-time (results not shown)). Note that the propagating spin waves generated at line A via parametric pumping can influence domain wall propagation [24][25][26][27] However, using a wire with different configuration of the field generation lines (i.e. line A is placed to the right of line C-D) we observe no change in the nucleation field and thus consider that the effect of spin waves on the nucleation process is negligible.…”

Section: Permalloy (Ni 81mentioning

confidence: 99%

Microwave assisted resonant domain wall nucleation in permalloy nanowires

Hayashi

Takahashi

Mitani

2012

Applied Physics Letters

View full text Add to dashboard Cite

We have designed a system to study microwave assisted domain wall nucleation in permalloy nanowires. We find a substantial decrease in the nucleation field when microwave fields are applied, in comparison to pulse fields. A clear resonance peak is observed in the frequency dependence of the nucleation field, which coincides with the uniform mode ferromagnetic resonance frequency. Owing to the well-defined nucleation process, the switching field distribution is small in contrast to previous reports. Our results show that localized microwave field provides an efficient tool for injecting domain walls into magnetic nanowires. * E-mail address: hayashi.masamitsu@nims.go.jp 2 Recent progress in the understanding of spin transfer torque and its related phenomena enabled development of domain wall based memory 1 and logic devices 2 . In particular, a magnetic shift register mimicking the so called "Racetrack memory" 1 has been demonstrated using localized magnetic fields to inject domain walls and spin polarized current to move them [3][4][5] . One challenge of exploring materials for domain wall based device applications is the difficulty in injecting domain walls into the nanowire since it typically requires large localized magnetic field 3,6 . Solid understanding of the nucleation process is thus required for further development of such devices.Microwave assisted magnetization reversal (MAMR) provides a unique tool to lower the magnetization switching field 7,8 . The concept has been demonstrated in a number of systems 7,9-18 but the understanding of the underlying physics is still developing. In most of the systems, it is likely that the magnetization reversal process involves nucleation and propagation of domain walls (exception is the coherent rotation of magnetic moments 12 ).Both domain wall (reversed domain) nucleation and propagation can be enhanced by the application of microwave field. However, its response may differ depending on the applied microwave frequency and thus may cause broadening of the switching field 9,10,17,18 . Thus to gain further insight into MAMR, it is essential to distinguish the effect of microwave field application on domain wall nucleation 19 and domain wall propagation 20,21 .Here we design a system to study the effect of microwave field application on a well-defined domain wall nucleation process in permalloy naonwires. Substantial drop in the nucleation field is observed for a microwave field frequency of ~3 GHz. We find a clear resonance peak in the frequency dependence of the nucleation field, in which the peak position corresponds to the ferromagnetic resonance uniform excitation mode. Fig. 1(a)). The width of line A parallel to the permalloy nanowire is set to ~2 m, large enough to cover the 600 nm wide nanowire. A signal generator or a pulse generator is connected to field generation lines A and/or B to apply localized magnetic field. Note that the Oersted field generated at line A (B), when current is passed along the line, is pointing transverse (parallel) to the wire...

show abstract

“…The importance of the nonadiabaticity for current-induced domain wall motion, has led to a number of theoretical [23][24][25][98][99][100][101][102][103][104][105][106] and experimental studies [94,[107][108][109][110][111][112] to determine the nonadiabatic spin torque parameter. Several mechanisms for the nonadiabatic spin transfer torque have been proposed.…”

Section: Non-local Spin Transfer Torque For a Narrow Domain Wallmentioning

confidence: 99%

Self-consistent calculation of spin transport and magnetization dynamics

et al. 2013

Self Cite

View full text Add to dashboard Cite

A spin-polarized current transfers its spin-angular momentum to a local magnetization, exciting various types of current-induced magnetization dynamics. So far, most studies in this field have focused on the direct effect of spin transport on magnetization dynamics, but ignored the feedback from the magnetization dynamics to the spin transport and back to the magnetization dynamics. Although the feedback is usually weak, there are situations when it can play an important role in the dynamics. In such situations, simultaneous, self-consistent calculations of the magnetization dynamics and the spin transport can accurately describe the feedback. This review describes in detail the feedback mechanisms, and presents recent progress in self-consistent calculations of the coupled dynamics. We pay special attention to three representative examples, where the feedback generates non-local effective interactions for the magnetization after the spin accumulation has been integrated out. Possibly the most dramatic feedback example is the dynamic instability in magnetic nanopillars with a single magnetic layer. This instability does not occur without non-local feedback. We demonstrate that full self-consistent calculations generate simulation results in much better agreement with experiments than previous calculations that addressed the feedback effect approximately.The next example is for more typical spin valve nanopillars. Although the effect of feedback is less dramatic because even without feedback the current can make stationary states unstable and induce magnetization oscillation, the feedback can still have important consequences. For instance, we show that the feedback can reduce the linewidth of oscillations, in agreement with experimental observations. A key aspect of this reduction is the suppression of the excitation of short wave length spin waves by the non-local feedback.Finally, we consider nonadiabatic electron transport in narrow domain walls. The non-local feedback in these systems leads to a significant renormalization of the effective nonadiabatic 3 spin transfer torque. These examples show that the self-consistent treatment of spin transport and magnetization dynamics is important for understanding the physics of the coupled dynamics and for providing a bridge between the ongoing research fields of current-induced magnetization dynamics and the newly emerging fields of magnetization-dynamics-induced generation of charge and spin currents.

show abstract

Current-Induced Control of Spin-Wave Attenuation

Cited by 108 publications

References 38 publications

Control of propagating spin waves via spin transfer torque in a metallic bilayer waveguide

Control of propagating spin waves via spin transfer torque in a metallic bilayer waveguide

Microwave assisted resonant domain wall nucleation in permalloy nanowires

Self-consistent calculation of spin transport and magnetization dynamics

Contact Info

Product

Resources

About