The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Mikihiko Oogane - One of the best experts on this subject based on the ideXlab platform.
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low Magnetic Damping and large negative anisotropic magnetoresistance in half metallic co2 xmn1 xsi heusler alloy films grown by molecular beam epitaxy
Applied Physics Letters, 2018Co-Authors: Mikihiko Oogane, Yasuo Ando, Anthony P Mcfadden, Kenji Fukuda, Masakiyo Tsunoda, C J PalmstromAbstract:Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.
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Low Magnetic Damping and large negative anisotropic magnetoresistance in half-metallic Co2−xMn1+xSi Heusler alloy films grown by molecular beam epitaxy
Applied Physics Letters, 2018Co-Authors: Mikihiko Oogane, Yasuo Ando, Anthony P Mcfadden, Kenji Fukuda, Masakiyo Tsunoda, C J PalmstromAbstract:Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.
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Magnetic Damping constant in Co-based full heusler alloy epitaxial films
Journal of Physics D: Applied Physics, 2015Co-Authors: Mikihiko Oogane, Takahide Kubota, Hiroshi Naganuma, Yasuo AndoAbstract:Co-based full-Heusler alloys, such as Co2MnSi and Co2MnGe, are expected to be used as half-metallic ferroMagnetic material, which has complete spin polarization. They are the most promising materials for realizing half-metallicity at room temperature due to their high Curie temperature. The optimization of the Magnetic Damping constant of ferroMagnetic materials is extremely important for achieving high-speed magnetization switching and reducing critical current density for spin torque transfer switching. We have systematically investigated the Magnetic Damping constant in Co-based full Heusler alloy epitaxial films. We found that the Gilbert Damping constant seems to be roughly proportional to the total density of states at the Fermi level (EF) by first principle calculation. A very small Magnetic Damping constant of 0.003 in the Co2Fe0.4Mn0.6Si epitaxial film was demonstrated. The small Magnetic Damping constant in Co2FexMn1−xSi films with x < 0.6 can be attributed to the half-metallicity of Heusler alloys. Co-based full Heusler alloys with both half-metallicity and small Magnetic Damping will be very useful for future applications based on spintronic devices.
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The Enhancement of Magnetic Damping in Fe4N Films with Increasing Thickness
Japanese Journal of Applied Physics, 2013Co-Authors: Shinji Isogami, Mikihiko Oogane, Akimasa Sakuma, Masakiyo Tsunoda, Migaku TakahashiAbstract:The film thickness dependence of the Magnetic Damping coefficient (α) was investigated by measuring the ferroMagnetic resonance (FMR) of Fe4N/NM (NM: Pt and Cu) bilayer films at room temperature. We observed that α in Fe4N/Pt films increased with increasing Fe4N film thickness. Moreover, the enhancement of α, which is represented by the difference in the α values of Fe4N/Pt and Fe4N/Cu films, also increased as the Fe4N film thickness increased. The behavior observed in the Fe4N system was the opposite of that observed for the conventional Ni–Fe system. We speculated two mechanisms occurring in Fe4N/Pt films, which are less Magnetic and/or nonMagnetic impurities in the Fe4N films and enhancement of the coercive force (Hc) with increasing Fe4N film thickness.
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Tunnel magnetoresistance effect and Magnetic Damping in half-metallic Heusler alloys
Philosophical transactions. Series A Mathematical physical and engineering sciences, 2011Co-Authors: Mikihiko Oogane, Shigemi MizukamiAbstract:Some full-Heusler alloys, such as Co(2)MnSi and Co(2)MnGe, are expected to be half-metallic ferroMagnetic material, which has complete spin polarization. They are the most promising materials for realizing half-metallicity at room temperature owing to their high Curie temperature. We demonstrate a huge tunnel magnetoresistance effect in a Magnetic tunnel junction using a Co(2)MnSi Heusler alloy electrode. This result proves high spin polarization of the Heusler alloy. We also demonstrate a small Magnetic Damping constant in Co(2)FeAl epitaxial film. The very high spin polarization and small Magnetic constant of Heusler alloys will be a great advantage for future spintronic device applications.
Yasuo Ando - One of the best experts on this subject based on the ideXlab platform.
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low Magnetic Damping and large negative anisotropic magnetoresistance in half metallic co2 xmn1 xsi heusler alloy films grown by molecular beam epitaxy
Applied Physics Letters, 2018Co-Authors: Mikihiko Oogane, Yasuo Ando, Anthony P Mcfadden, Kenji Fukuda, Masakiyo Tsunoda, C J PalmstromAbstract:Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.
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Low Magnetic Damping and large negative anisotropic magnetoresistance in half-metallic Co2−xMn1+xSi Heusler alloy films grown by molecular beam epitaxy
Applied Physics Letters, 2018Co-Authors: Mikihiko Oogane, Yasuo Ando, Anthony P Mcfadden, Kenji Fukuda, Masakiyo Tsunoda, C J PalmstromAbstract:Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.
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Magnetic Damping constant in Co-based full heusler alloy epitaxial films
Journal of Physics D: Applied Physics, 2015Co-Authors: Mikihiko Oogane, Takahide Kubota, Hiroshi Naganuma, Yasuo AndoAbstract:Co-based full-Heusler alloys, such as Co2MnSi and Co2MnGe, are expected to be used as half-metallic ferroMagnetic material, which has complete spin polarization. They are the most promising materials for realizing half-metallicity at room temperature due to their high Curie temperature. The optimization of the Magnetic Damping constant of ferroMagnetic materials is extremely important for achieving high-speed magnetization switching and reducing critical current density for spin torque transfer switching. We have systematically investigated the Magnetic Damping constant in Co-based full Heusler alloy epitaxial films. We found that the Gilbert Damping constant seems to be roughly proportional to the total density of states at the Fermi level (EF) by first principle calculation. A very small Magnetic Damping constant of 0.003 in the Co2Fe0.4Mn0.6Si epitaxial film was demonstrated. The small Magnetic Damping constant in Co2FexMn1−xSi films with x < 0.6 can be attributed to the half-metallicity of Heusler alloys. Co-based full Heusler alloys with both half-metallicity and small Magnetic Damping will be very useful for future applications based on spintronic devices.
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Gilbert Magnetic Damping constant of epitaxially grown Co-based Heusler alloy thin films
Applied Physics Letters, 2010Co-Authors: Mikihiko Oogane, Takahide Kubota, Hiroshi Naganuma, Shigemi Mizukami, Yohei Kota, Akimasa Sakuma, Yasuo AndoAbstract:The Magnetic Damping constant in a series of Co2MnAlxSi1−x and Co2FexMn1−xSi Heusler alloy epitaxial films were systematically investigated by using ferroMagnetic resonance technique. The determined Magnetic Damping constant is roughly proportional to the density of states at the Fermi energy of the first principle calculation. The result is consistent with the theoretical prediction when taking spin-orbit interaction into account. The small Gilbert Damping constant for the fabricated films other than the Co2FexMn1−xSi film with x>0.6 can be originated in the half-metallic electronic structure of Heusler alloys.
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Magnetic Damping constant of Co2FeSi Heusler alloy thin film
Journal of Applied Physics, 2007Co-Authors: Mikihiko Oogane, Yasuo Ando, Resul Yilgin, M. Shinano, Satoshi Yakata, Yuya Sakuraba, Terunobu MiyazakiAbstract:Co2FeSi films were prepared using magnetron sputtering technique on Cr buffer layers and MgO(001) substrates at various annealing temperatures. We investigated the crystal structures, Magnetic properties (Ms and Hc), surface roughness, and Magnetic Damping constants (α) of the prepared Co2FeSi films. Out-of-plane angular dependences of the resonance field and the linewidth of the ferroMagnetic resonance spectra were measured and fitted using the Landau-Lifshitz-Gilbert equation to determine the Damping constant. The as-deposited Co2FeSi film exhibited an amorphous and disordered structure; the α value was 0.008. In contrast, the Co2FeSi films annealed over 300°C showed epitaxial growth and had a (001)-oriented and L21 ordered structure. Both disordered and L21 ordered Co2FeSi films showed similar α values.Co2FeSi films were prepared using magnetron sputtering technique on Cr buffer layers and MgO(001) substrates at various annealing temperatures. We investigated the crystal structures, Magnetic properties (Ms and Hc), surface roughness, and Magnetic Damping constants (α) of the prepared Co2FeSi films. Out-of-plane angular dependences of the resonance field and the linewidth of the ferroMagnetic resonance spectra were measured and fitted using the Landau-Lifshitz-Gilbert equation to determine the Damping constant. The as-deposited Co2FeSi film exhibited an amorphous and disordered structure; the α value was 0.008. In contrast, the Co2FeSi films annealed over 300°C showed epitaxial growth and had a (001)-oriented and L21 ordered structure. Both disordered and L21 ordered Co2FeSi films showed similar α values.
C J Palmstrom - One of the best experts on this subject based on the ideXlab platform.
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low Magnetic Damping and large negative anisotropic magnetoresistance in half metallic co2 xmn1 xsi heusler alloy films grown by molecular beam epitaxy
Applied Physics Letters, 2018Co-Authors: Mikihiko Oogane, Yasuo Ando, Anthony P Mcfadden, Kenji Fukuda, Masakiyo Tsunoda, C J PalmstromAbstract:Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.
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Low Magnetic Damping and large negative anisotropic magnetoresistance in half-metallic Co2−xMn1+xSi Heusler alloy films grown by molecular beam epitaxy
Applied Physics Letters, 2018Co-Authors: Mikihiko Oogane, Yasuo Ando, Anthony P Mcfadden, Kenji Fukuda, Masakiyo Tsunoda, C J PalmstromAbstract:Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.Co2−xMn1+xSi films with various composition x were epitaxially grown using molecular beam epitaxy (MBE). High crystallinity and atomic ordering in the prepared Co2−xMn1+xSi films were observed, and their Magnetic Damping and anisotropic magnetoresistance (AMR) effect were systematically investigated. An ultra-low Magnetic Damping constant of 0.0007 was obtained in the Co2−xMn1+xSi film with a valence electron number (NV) of about 29.0. Additionally, a relatively large negative AMR effect was observed in the Co2−xMn1+xSi films that had a NV of about 29.0. This low Damping and the large negative AMR effect indicate that epitaxial Co2−xMn1+xSi films with high atomic ordering grown by MBE possess a high-spin polarization.
Yuri Suzuki - One of the best experts on this subject based on the ideXlab platform.
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Ultra-low Magnetic Damping in epitaxial Li0.5Fe2.5O4 thin films
Applied Physics Letters, 2020Co-Authors: Xin Yu Zheng, Lauren Riddiford, Jacob J. Wisser, Satoru Emori, Yuri SuzukiAbstract:The realization of more energy efficient nanoMagnetic information devices relies on the existence of Magnetic insulators capable of supporting pure spin currents in the absence of a dissipative charge current. Currently, there is a limited number of thin-film Magnetic insulators with low Magnetic Damping. Li0.5Fe2.5O4 (LFO) is well known to possess the lowest Damping among the bulk spinel structure oxides, but, thus far, LFO thin films have not lived up to these expectations. Here, we demonstrate low Magnetic Damping (even lower than typical bulk values) and bulk magnetization in 3 nm thick epitaxial LFO thin films. At room temperature, SQUID magnetometry shows a high saturation magnetization of 320 kA/m, and broadband ferroMagnetic resonance measurements yield an effective Gilbert Damping parameter of 1.3 × 10 − 3, which is among the lowest reported for ferro-/ferriMagnetic films of comparable thickness. Our results show the promise of LFO as a candidate material for spin current-based spintronics.
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The role of iron in Magnetic Damping of Mg(Al,Fe)2O4 spinel ferrite thin films
Applied Physics Letters, 2020Co-Authors: Jacob J. Wisser, Lauren Riddiford, Satoru Emori, Aaron Altman, Padraic Shafer, Christoph Klewe, Alpha T. N'diaye, Elke Arenholz, Yuri SuzukiAbstract:We have investigated magnesium aluminum ferrite thin films with a range of iron concentrations and identified the optimal iron content to obtain high crystalline quality thin films with the low Magnetic Damping required for spin current-based applications. Epitaxial MgAl 2 − x FexO4 films with 0.8 < x
Zongzhi Zhang - One of the best experts on this subject based on the ideXlab platform.
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topological surface state manipulation of Magnetic Damping and surface anisotropy in topological insulator nonmagnet cofe heterostructures
Physical Review B, 2021Co-Authors: Yang Ren, Q. Y. Jin, Zongzhi ZhangAbstract:The recent advances of high spin-orbit torque efficiency in ferroMagnetic/topological insulator (TI) structures hold great promise for the development of high-performance spintronic devices. However, the roles of spin-momentum-locked Dirac surface states (SSs) and the interfacial Magnetic proximity effect (MPE) on dynamic Magnetic properties are still under debate. Here, we quantitatively distinguish the manipulation effects of SSs and MPE on Magnetic Damping and surface anisotropy in TI/nonmagnet/CoFe heterostructures. We found that, in addition to the common spin pumping contribution stemming from SSs, Damping enhancement also consists of an obvious MPE contribution to the TI/CoFe material system. Moreover, the increased surface Magnetic anisotropy for the CoFe films grown on top of a TI layer is believed to arise mainly from the interfacial atomic intermixing. Our paper sheds light on the effects of SSs and MPE on magnetization dynamics, which offer exciting opportunities for developing TI-based spintronics.
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Modulation of Magnetic Damping in antiferromagnet/CoFeB heterostructures
Applied Physics Letters, 2020Co-Authors: Zhendong Zhu, Yang Ren, Shitao Lou, Q. Y. Jin, Zongzhi ZhangAbstract:The modulation of antiferroMagnetic (AFM) material and thermal annealing treatment on the Magnetic Damping of various AFM/CoFeB (CFB) samples have been systematically studied with the time-resolved magneto-optical Kerr effect. It is found the saturated Magnetic Damping factor αs increases considerably after introducing a thin MnIr or MnPt AFM layer. As a thin Al spacer of tAl = 0–2 nm is inserted, αs is found to decrease rapidly, reaching nearly the same value as that of the single CFB film at tAl = 2 nm. The result suggests that the AFM layer is not a good spin sink material and the surprisingly strong decrease in the Damping factor is mainly attributed to the reduced direct exchange coupling between CoFe and Mn spins at the AFM/FM interface. Moreover, in spite of the exchange bias effect occurring or not, a similar monotonic increasing trend of αs with the increasing AFM layer thickness is observed for the as-deposited and annealed AFM/CFB samples, indicating that the enhanced Magnetic Damping at an elevated annealing temperature is mainly related to the increased interface roughness and atomic diffusion. These findings provide deeper insights into the role of the AFM/FM interface in magnetization dynamics, which will be helpful for future spintronic applications.
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Large anisotropy of Magnetic Damping in amorphous CoFeB films on GaAs(001).
Journal of physics. Condensed matter : an Institute of Physics journal, 2020Co-Authors: Ji Wang, Zongzhi Zhang, Zhendong Zhu, Zhaocong Huang, Ya Zhai, Rongkun Zheng, Yuan Yuan, Ruobai LiuAbstract:Amorphous CoFeB films grown on GaAs(001) substrates demonstrating significant in-plane uniaxial Magnetic anisotropy were investigated by vector network analyzer ferroMagnetic resonance. Distinct in-plane anisotropy of Magnetic Damping, with a largest maximum-minimum Damping ratio of about 109%, was observed via analyzing the frequency dependence of linewidth in a linear manner. As the CoFeB film thickness increases from 3.5 nm to 30 nm, the amorphous structure for all the CoFeB films is maintained while the Magnetic Damping anisotropy decreases significantly. In order to reveal the inherent mechanism responsible for the anisotropic Magnetic Damping, studies on time-resolved magneto-optical Kerr effect and high resolution transmission electron microscopy were performed. Those results indicate that the in-plane angular dependent anisotropic Damping mainly originates from two-magnon scattering, while the Gilbert Damping keeps almost unchanged.
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annealing effect and interlayer modulation on Magnetic Damping of cofeb interlayer pt thin films
Applied Physics Letters, 2018Co-Authors: Zhendong Zhu, Minghong Tang, Yang Ren, Q. Y. Jin, Bingcheng Zhao, Weihua Zhu, Zongzhi ZhangAbstract:The annealing effect and interlayer (IL) modulation on the Magnetic Damping properties of CoFeB/IL/Pt (IL = Ta or Ru) multilayers have been systematically studied by the time-resolved magneto-optical Kerr effect. It is found that after inserting a thin IL, the saturated Magnetic Damping factor αs drops considerably due to the reduced spin pumping effect. By fitting the curves of αs versus IL thickness, spin diffusion lengths of Ta and Ru are determined to be 3.07 and 3.59 nm, respectively. Interestingly, for the CoFeB samples with different capping layers of Pt, Ta/Pt, or Ru/Pt, the αs values exhibit an identical non-monotonic variation tendency as annealing temperature (Ta) increases. It first rises to a maximum at Ta ∼ 100 °C and then decreases, reaching a minimum value (αs = 0.021–0.011) at Ta ∼ 300 °C. After that, αs starts to increase again. Such a complicated variation behavior is attributed to two-magnon scattering contribution, which originates from the change in the CoFeB surface roughness and interfacial atomic intermixing induced by thermal annealing. This study provides a deep understanding and effective control of Magnetic Damping for practical design of high performance spintronic devices.The annealing effect and interlayer (IL) modulation on the Magnetic Damping properties of CoFeB/IL/Pt (IL = Ta or Ru) multilayers have been systematically studied by the time-resolved magneto-optical Kerr effect. It is found that after inserting a thin IL, the saturated Magnetic Damping factor αs drops considerably due to the reduced spin pumping effect. By fitting the curves of αs versus IL thickness, spin diffusion lengths of Ta and Ru are determined to be 3.07 and 3.59 nm, respectively. Interestingly, for the CoFeB samples with different capping layers of Pt, Ta/Pt, or Ru/Pt, the αs values exhibit an identical non-monotonic variation tendency as annealing temperature (Ta) increases. It first rises to a maximum at Ta ∼ 100 °C and then decreases, reaching a minimum value (αs = 0.021–0.011) at Ta ∼ 300 °C. After that, αs starts to increase again. Such a complicated variation behavior is attributed to two-magnon scattering contribution, which originates from the change in the CoFeB surface roughness and in...
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Annealing effect and interlayer modulation on Magnetic Damping of CoFeB/interlayer/Pt thin films
Applied Physics Letters, 2018Co-Authors: Zhendong Zhu, Minghong Tang, Yang Ren, Q. Y. Jin, Bingcheng Zhao, Weihua Zhu, Zongzhi ZhangAbstract:The annealing effect and interlayer (IL) modulation on the Magnetic Damping properties of CoFeB/IL/Pt (IL = Ta or Ru) multilayers have been systematically studied by the time-resolved magneto-optical Kerr effect. It is found that after inserting a thin IL, the saturated Magnetic Damping factor αs drops considerably due to the reduced spin pumping effect. By fitting the curves of αs versus IL thickness, spin diffusion lengths of Ta and Ru are determined to be 3.07 and 3.59 nm, respectively. Interestingly, for the CoFeB samples with different capping layers of Pt, Ta/Pt, or Ru/Pt, the αs values exhibit an identical non-monotonic variation tendency as annealing temperature (Ta) increases. It first rises to a maximum at Ta ∼ 100 °C and then decreases, reaching a minimum value (αs = 0.021–0.011) at Ta ∼ 300 °C. After that, αs starts to increase again. Such a complicated variation behavior is attributed to two-magnon scattering contribution, which originates from the change in the CoFeB surface roughness and interfacial atomic intermixing induced by thermal annealing. This study provides a deep understanding and effective control of Magnetic Damping for practical design of high performance spintronic devices.The annealing effect and interlayer (IL) modulation on the Magnetic Damping properties of CoFeB/IL/Pt (IL = Ta or Ru) multilayers have been systematically studied by the time-resolved magneto-optical Kerr effect. It is found that after inserting a thin IL, the saturated Magnetic Damping factor αs drops considerably due to the reduced spin pumping effect. By fitting the curves of αs versus IL thickness, spin diffusion lengths of Ta and Ru are determined to be 3.07 and 3.59 nm, respectively. Interestingly, for the CoFeB samples with different capping layers of Pt, Ta/Pt, or Ru/Pt, the αs values exhibit an identical non-monotonic variation tendency as annealing temperature (Ta) increases. It first rises to a maximum at Ta ∼ 100 °C and then decreases, reaching a minimum value (αs = 0.021–0.011) at Ta ∼ 300 °C. After that, αs starts to increase again. Such a complicated variation behavior is attributed to two-magnon scattering contribution, which originates from the change in the CoFeB surface roughness and in...
