Magnetization damping in noncollinear spin valves with antiferromagnetic interlayer couplings

Chiba, Takahiro; Bauer, G.; Takahashi, Saburo

doi:10.1103/physrevb.92.054407

Cited by 29 publications

(18 citation statements)

References 67 publications

(82 reference statements)

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“…However, as the interlayer exchange coupling (J IEC ) seen in SAFs is smaller than the direct exchange coupling seen in single-phase antiferromagnets, the resonance frequencies are also reduced. This opens up additional possibilities for AFM-based devices, extending the range of frequencies that can be generated, and provides a method to tailor the frequency obtained through controlling the coupling interaction [31,32]. The interlayer coupling results from the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction [33], which for an appropriate choice of spacer layer such as Ru is responsible for an oscillatory short-range interaction that can promote ferromagnetic or antiferromagnetic layer alignment depending on spacer layer thickness.…”

Section: Introductionmentioning

confidence: 99%

Zero-field Optic Mode Beyond 20 GHz in a Synthetic Antiferromagnet

et al. 2020

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Antiferromagnets have considerable potential as spintronic materials. Their dynamic properties include resonant modes at frequencies higher than can be observed in conventional ferromagnetic materials. An alternative to single-phase antiferromagnets are synthetic antiferromagnets (SAFs), engineered structures of exchange-coupled ferromagnet/nonmagnet/ferromagnet trilayers. SAFs have significant advantages due to the wide-ranging tunability of their magnetic properties and inherent compatibility with current device technologies, such as those used for Spin-transfer-torque magnetic random-access memory production. Here we report the dynamic properties of fully compensated SAFs using broadband ferromagnetic resonance and demonstrate resonant optic modes in addition to the conventional acoustic (Kittel) mode. These optic modes possess the highest zero-field frequencies observed in SAFs to date with resonances of 18 and 21 GHz at the first and second peaks in antiferromagnetic Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling, respectively. In contrast to previous SAF reports that focus only on the first RKKY antiferromagnetic coupling peak, we show that a higher optic mode frequency is obtained for the second antiferromagnetic coupling peak. We ascribe this to the smoother interfaces associated with a thicker nonmagnetic layer. This demonstrates the importance of interface quality to achieving high-frequency optic mode dynamics entering the subterahertz range.

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Section: Introductionmentioning

confidence: 99%

Zero-field Optic Mode Beyond 20 GHz in a Synthetic Antiferromagnet

et al. 2020

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“…1(b) and 1(c), respectively. 40,49 The optic mode is particularly important for our application because it has a net dynamic moment along the y axis. These resonance frequencies are shown in Fig.…”

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confidence: 99%

Using magnetic hyperbolic metamaterials as high frequency tunable filters

Macêdo

Livesey

Camley

2018

Applied Physics Letters

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Metamaterials have enabled a series of major advances in optical devices in the past decade. Here, we suggest a type of hyperbolic metamaterial based on spin canting in magnetic multi-layers. We show that these structures have unique features in microwave waveguides that act as tunable filters. In the resulting band pass filter, we demonstrate an exceptional frequency tunability of 30 GHz with external fields smaller than 500 Oe. Unlike single metallic ferromagnetic films, we also demonstrate a high-frequency band-stop filter at very low fields.

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“…Spin pumping can have a pronounced angular dependence, arising from the relative alignment of the two magnetic layers and the magnitude of precession [19][20][21]. In this case, antiparallel alignment leads to more efficient absorption of the spin current as compensation of the pumped angular momentum drops [22].…”

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confidence: 99%

Anisotropic Absorption of Pure Spin Currents

et al. 2016

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Spin transfer in magnetic multilayers offers the possibility of ultrafast, low-power device operation. We report a study of spin pumping in spin valves, demonstrating that a strong anisotropy of spin pumping from the source layer can be induced by an angular dependence of the total Gilbert damping parameter, α, in the spin sink layer. Using lab- and synchrotron-based ferromagnetic resonance, we show that an in-plane variation of damping in a crystalline Co_{50}Fe_{50} layer leads to an anisotropic α in a polycrystalline Ni_{81}Fe_{19} layer. This anisotropy is suppressed above the spin diffusion length in Cr, which is found to be 8 nm, and is independent of static exchange coupling in the spin valve. These results offer a valuable insight into the transmission and absorption of spin currents, and a mechanism by which enhanced spin torques and angular control may be realized for next-generation spintronic devices.

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Magnetization damping in noncollinear spin valves with antiferromagnetic interlayer couplings

Cited by 29 publications

References 67 publications

Zero-field Optic Mode Beyond 20 GHz in a Synthetic Antiferromagnet

Zero-field Optic Mode Beyond 20 GHz in a Synthetic Antiferromagnet

Using magnetic hyperbolic metamaterials as high frequency tunable filters

Anisotropic Absorption of Pure Spin Currents

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