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Liang Qiao - One of the best experts on this subject based on the ideXlab platform.
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high frequency electromagnetic properties of soft magnetic nd2co17 micron flakes fractured along c crystal plane with natural resonance frequency exceeding 10 ghz
Applied Physics Letters, 2016Co-Authors: Yongbo Zhang, Liang Qiao, Peng Wang, Ying Wang, Tao WangAbstract:Planar Anisotropy Nd2Co17 flakes fractured along c crystal plane were fabricated by surfactant-assisted high-energy ball milling technique. The magnetic flakes have a diameter range of 5–20 μm and a typical thickness of approximately 120 nm. The frequency dependence of complex permeability of Nd2Co17 epoxy resin composite has been investigated in the frequency range of 0.1–18 GHz. The measurement results show that the natural resonance frequency reaches 12.5 GHz while the initial permeability survives up to 2.26. The superior high frequency properties come from the large out-of-plane Anisotropy field and the flake structure fractured along the c crystal plane of Nd2Co17. The Planar anisotropic Nd2Co17 flakes have significant potential applications in the high-frequency devices working in the frequency beyond 10 GHz.
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Greatly enhanced microwave absorbing properties of Planar Anisotropy carbonyl-iron particle composites
Journal of Magnetism and Magnetic Materials, 2015Co-Authors: Liang Qiao, Tao Wang, Rui Han, Liyun TangAbstract:Abstract This paper investigates the high permeability and high resonance frequency characteristics of carbonyl-iron particle composites at microwave range. It finds that the key factor to keep both high microwave absorbing characteristics is the Planar Anisotropy. The effective permeability of Planar Anisotropy carbonyl-iron particles/nonmagnetic matrix composition in high frequency is measured and calculated. In contrast to the sphere shaped particles with no Planar Anisotropy, the permeability and resonance frequency of flake particles are greatly enhanced by introducing the Planar Anisotropy, and the permeability can be further enhanced by using a rotational orientation method to get higher Planar Anisotropy. As the use of the Planar Anisotropy, the flake soft magnetic particles increase the natural resonant frequencies so as to lead the higher real part and the imaginary part of the permeability in a broadband range. The resonance peak of flake particles is simulated by using the combination of the Landau–Lifshitz–Gilbert equation and Bruggeman’s effective medium theory, considering the correction of shape factor. Our theory simulation agrees well with the experimental data.
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microwave absorption properties of oriented pr2fe17n3 δ particles paraffin composite with Planar Anisotropy
Journal of Alloys and Compounds, 2014Co-Authors: Guoguo Tan, Wen-liang Zuo, Jianqiang Wei, Liang QiaoAbstract:Planar Anisotropy Pr2Fe17N3 (delta) soft magnetic particles/paraffin composite was prepared. Rotational orientation through an externally applied magnetic field was used to induce the easy magnetization planes of the particles to move parallel to each other. Measurement of electromagnetic parameters show that orientation led to a higher complex permeability and a lower permittivity. The complex permeability and permittivity of the unoriented and oriented composites were used to analyze their electromagnetic wave absorption properties. The results show that the absorption properties, including reflection loss peak intensity and bandwidth of the oriented composite, were enhanced. (C) 2013 Elsevier B.V. All rights reserved.
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greatly enhanced permeability for Planar Anisotropy ce2fe17n3 δ compound with rotational orientation in various external magnetic fields
Journal of Magnetism and Magnetic Materials, 2012Co-Authors: Rui Han, Wen-liang Zuo, Liang QiaoAbstract:A new Planar Anisotropy Ce2Fe17H3-delta compound as an electromagnetic absorption material was prepared by the arc melting method. The influence of rotational orientation in various magnetic fields on the complex permeability and orientation degrees of the compound/paraffin composites was systematically studied. It is found that the orientation plays an important role in complex permeability and orientation degrees. For the composite with rotational orientation in 1.6 T, the real permeability reaches a large value of 4.8 at 2 GHz and the imaginary part reaches 2.6 at 5.5 GHz; on the other hand, the orientation degree reaches 62.4%. It is evident that the oriented Ce2Fe17N3-delta composite with Planar Anisotropy may have potential applications as microwave absorption materials. (C) 2012 Elsevier BV. All rights reserved.
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electromagnetic performance and microwave absorbing property of nanocrystalline sm2fe14b compound
Applied Physics A, 2012Co-Authors: Haibo Yi, Liang Qiao, Fashen LiAbstract:A new Planar Anisotropy Sm2Fe14B nanocrystal as an electromagnetic absorption material was prepared by melt-spinning method. The electromagnetic and microwave absorbing properties of Sm2Fe14B nanocrystal/nonmagnetic matrix composite in the frequency range of 0.1–10 GHz were measured and calculated. At the perfect matching point (2.9 GHz), the minimum reflection loss reaches −42.0 dB at the matching thickness of 3.1 mm. Furthermore, the calculation shows that the normalized input impedance Zin/Z0 equals 1, but the modulus of the ratio between the complex permittivity and permeability |e/μ| is far away from unity at the perfect matching point. The effective permeability of the composite was simulated using the combination of the Landau–Lifshitz–Gilbert equation and Bruggeman’s effective medium theory; the agreement between the experimental data and the theoretical one demonstrates that the magnetic loss in the composite is mainly caused by natural resonance.
Tao Wang - One of the best experts on this subject based on the ideXlab platform.
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Planar anisotropic shubnikov de haas oscillations of two dimensional electron gas in aln gan heterostructure
Applied Physics Letters, 2019Co-Authors: L Yang, Tao Wang, J J Wang, Ping Wang, Ding Wang, Xuelin Yang, Xinqiang Wang, Bo ShenAbstract:Two-dimensional electron gas (2DEG) buried in ultrathin barrier AlN/GaN heterostructures is the key to exploit high-speed and high-power devices in the aspect of modern semiconductor electronics. Here, we report Shubnikov-de-Haas oscillations of the 2DEG in an AlN/GaN heterostructure with Planar Anisotropy along [11-20] and [1-100] axes. The effective mass extracted from oscillations exhibits an evident disparity, as (0.19 ± 0.02)me along the [11-20] axis and (0.24 ± 0.02)me along the [1-100] axis. Meanwhile, the quantum scattering time is obviously different along the aforementioned directions, with 0.08 vs 0.26 ps for the first subband and 0.19 vs 0.27 ps for the second subband. Both the effective mass and the quantum scattering time contribute to the Anisotropy of the quantum mobility, which are 750 and 1907 cm2/V s for E1 and 1760 and 1980 cm2/V s for E2 along [11-20] and [1-100] axes, respectively. These parameters are obviously crucial in designing devices using AlN/GaN heterostructures.
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high frequency electromagnetic properties of soft magnetic nd2co17 micron flakes fractured along c crystal plane with natural resonance frequency exceeding 10 ghz
Applied Physics Letters, 2016Co-Authors: Yongbo Zhang, Liang Qiao, Peng Wang, Ying Wang, Tao WangAbstract:Planar Anisotropy Nd2Co17 flakes fractured along c crystal plane were fabricated by surfactant-assisted high-energy ball milling technique. The magnetic flakes have a diameter range of 5–20 μm and a typical thickness of approximately 120 nm. The frequency dependence of complex permeability of Nd2Co17 epoxy resin composite has been investigated in the frequency range of 0.1–18 GHz. The measurement results show that the natural resonance frequency reaches 12.5 GHz while the initial permeability survives up to 2.26. The superior high frequency properties come from the large out-of-plane Anisotropy field and the flake structure fractured along the c crystal plane of Nd2Co17. The Planar anisotropic Nd2Co17 flakes have significant potential applications in the high-frequency devices working in the frequency beyond 10 GHz.
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Greatly enhanced microwave absorbing properties of Planar Anisotropy carbonyl-iron particle composites
Journal of Magnetism and Magnetic Materials, 2015Co-Authors: Liang Qiao, Tao Wang, Rui Han, Liyun TangAbstract:Abstract This paper investigates the high permeability and high resonance frequency characteristics of carbonyl-iron particle composites at microwave range. It finds that the key factor to keep both high microwave absorbing characteristics is the Planar Anisotropy. The effective permeability of Planar Anisotropy carbonyl-iron particles/nonmagnetic matrix composition in high frequency is measured and calculated. In contrast to the sphere shaped particles with no Planar Anisotropy, the permeability and resonance frequency of flake particles are greatly enhanced by introducing the Planar Anisotropy, and the permeability can be further enhanced by using a rotational orientation method to get higher Planar Anisotropy. As the use of the Planar Anisotropy, the flake soft magnetic particles increase the natural resonant frequencies so as to lead the higher real part and the imaginary part of the permeability in a broadband range. The resonance peak of flake particles is simulated by using the combination of the Landau–Lifshitz–Gilbert equation and Bruggeman’s effective medium theory, considering the correction of shape factor. Our theory simulation agrees well with the experimental data.
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complex permeability and microwave absorbing properties of Planar Anisotropy carbonyl iron ni0 5zn0 5fe2o4 composite in quasimicrowave band
Materials Chemistry and Physics, 2012Co-Authors: Rui Han, Tao Wang, Lu-qian Gong, Liang QiaoAbstract:Abstract Planar Anisotropy carbonyl-iron (PACI)/Ni 0.5 Zn 0.5 Fe 2 O 4 composite as absorbent filler in quasimicrowave band has been synthesized via ball-milling technique and solvothermal method. The effective permeability of the composite was measured and calculated. The result indicates that the magnetic loss in the composite is mainly caused by the natural resonance. Compared with the uncoated PACI particles, the permittivity of the composite decreased dramatically, and hence a dramatic enhancement of reflection loss (RL) was obtained in quasimicrowave band. This result indicates that our PACI/ferrite composite can be used as potential microwave absorbers in quasimicrowave band for its novel microwave properties.
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complex permeability and microwave absorption properties of Planar Anisotropy ce2fe17n3 δ particles
Journal of Alloys and Compounds, 2011Co-Authors: Wen-liang Zuo, Xiao Chi, Liang Qiao, Tao WangAbstract:Abstract The effective complex permeability of Ce2Fe17N3−δ particles/epoxy resin composites with various volume concentrations p were measured in the frequency range of 0.1–15 GHz. The intrinsic quasi-static permeability μ ′ 0 , i of Ce2Fe17N3−δ particle was calculated by Bruggerman's (BG) effective medium theory. Meanwhile, the effective quasi-static permeability μ ′ 0 , e of composites were calculated by the BG theory and modified Bruggerman's (MBG) effective medium theory, respectively. Through analyzing the experiment data, the effective shape factors of Ce2Fe17N3−δ composites were determined. The intrinsic natural resonance frequency of Ce2Fe17N3−δ was obtained using Landua–Lifshitz–Gilbert (LLG) equation. The minimum EM absorbing values with RL ≤ −30 dB are observed for all the volume concentrations.
M Belmeguenai - One of the best experts on this subject based on the ideXlab platform.
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microstrip line ferromagnetic resonance and brillouin light scattering investigations of magnetic properties of co2mnge heusler thin films
Physical Review B, 2009Co-Authors: M Belmeguenai, F Zighem, Y Roussigne, S M Cherif, P Moch, K Westerholt, Georg Woltersdorf, G BayreutherAbstract:Co2MnGe films of different thicknesses (34, 55, and 83 nm) were grown by rf sputtering at 400 °C on single-crystal Al2O3 corundum substrates showing an in-plane c axis. Their dynamic magnetic properties were studied using conventional and microstrip line (MS) ferromagnetic resonances (FMRs), as well as Brillouin light scattering (BLS) techniques. The effective magnetizations and gyromagnetic factors are first deduced from the resonance spectra involving the uniform magnetic mode under in-plane and out-of-plane magnetic applied fields. The angular dependence of the frequency, measured under a weak in-plane magnetic applied field, then allows deriving of the parameters describing the in-plane magnetic Anisotropy. In the 34- and 55-nm-thick films, its behavior is described assuming a magnetic energy density showing an orthorhombic symmetry with a twofold axis normal to the film and Planar Anisotropy axes at ±pi/4 of the c axis of the substrate; however, due to the comparative deduced values of the pertinent coefficients, this energy density is predominantly tetragonal. In the thickest film (83 nm), one of the Planar Anisotropy axes is parallel to c and approximate tetragonal symmetry is no more observed. Moreover, the orthorhombic symmetry is not completely fulfilled and a small misalignment between the principal directions connected to the uniaxial and the fourfold energy terms appears. Finally, the perpendicular surface standing modes, which are observed in MS-FMR and in BLS spectra, allow evaluation of the exchange stiffness constant. Good agreement between BLS and MS-FMR measurements has been found.
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microstrip line ferromagnetic resonance and brillouin light scattering investigations of magnetic properties of co 2 mnge heusler thin films
Physical Review B, 2009Co-Authors: M Belmeguenai, F Zighem, Y Roussigne, S M Cherif, P Moch, K Westerholt, Georg Woltersdorf, G BayreutherAbstract:Co2MnGe films of different thicknesses (34, 55, and 83 nm) were grown by rf sputtering at 400 °C on single-crystal Al2O3 corundum substrates showing an in-plane c axis. Their dynamic magnetic properties were studied using conventional and microstrip line (MS) ferromagnetic resonances (FMRs), as well as Brillouin light scattering (BLS) techniques. The effective magnetizations and gyromagnetic factors are first deduced from the resonance spectra involving the uniform magnetic mode under in-plane and out-of-plane magnetic applied fields. The angular dependence of the frequency, measured under a weak in-plane magnetic applied field, then allows deriving of the parameters describing the in-plane magnetic Anisotropy. In the 34- and 55-nm-thick films, its behavior is described assuming a magnetic energy density showing an orthorhombic symmetry with a twofold axis normal to the film and Planar Anisotropy axes at ±pi/4 of the c axis of the substrate; however, due to the comparative deduced values of the pertinent coefficients, this energy density is predominantly tetragonal. In the thickest film (83 nm), one of the Planar Anisotropy axes is parallel to c and approximate tetragonal symmetry is no more observed. Moreover, the orthorhombic symmetry is not completely fulfilled and a small misalignment between the principal directions connected to the uniaxial and the fourfold energy terms appears. Finally, the perpendicular surface standing modes, which are observed in MS-FMR and in BLS spectra, allow evaluation of the exchange stiffness constant. Good agreement between BLS and MS-FMR measurements has been found.
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microstrip line ferromagnetic resonance and brillouin light scattering investigations of magnetic properties of co 2 mnge heusler thin films
Physical Review B, 2009Co-Authors: M Belmeguenai, F Zighem, Y Roussigne, S M Cherif, P Moch, K Westerholt, Georg Woltersdorf, G BayreutherAbstract:Co2MnGe films of different thicknesses (34, 55, and 83 nm) were grown by rf sputtering at 400 degrees C on single-crystal Al2O3 corundum substrates showing an in-plane c axis. Their dynamic magnetic properties were studied using conventional and microstrip line (MS) ferromagnetic resonances (FMRs), as well as Brillouin light scattering (BLS) techniques. The effective magnetizations and gyromagnetic factors are first deduced from the resonance spectra involving the uniform magnetic mode under in-plane and out-of-plane magnetic applied fields. The angular dependence of the frequency, measured under a weak in-plane magnetic applied field, then allows deriving of the parameters describing the in-plane magnetic Anisotropy. In the 34- and 55-nm-thick films, its behavior is described assuming a magnetic energy density showing an orthorhombic symmetry with a twofold axis normal to the film and Planar Anisotropy axes at +/-pi/4 of the c axis of the substrate; however, due to the comparative deduced values of the pertinent coefficients, this energy density is predominantly tetragonal. In the thickest film (83 nm), one of the Planar Anisotropy axes is parallel to c and approximate tetragonal symmetry is no more observed. Moreover, the orthorhombic symmetry is not completely fulfilled and a small misalignment between the principal directions connected to the uniaxial and the fourfold energy terms appears. Finally, the perpendicular surface standing modes, which are observed in MS-FMR and in BLS spectra, allow evaluation of the exchange stiffness constant. Good agreement between BLS and MS-FMR measurements has been found.
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microstrip line ferromagnetic resonance and brillouin light scattering investigations of magnetic properties of co 2 mnge heusler thin films
Physical Review B, 2009Co-Authors: M Belmeguenai, F Zighem, Y Roussigne, S M Cherif, P Moch, K Westerholt, Georg Woltersdorf, G BayreutherAbstract:${\text{Co}}_{2}\text{MnGe}$ films of different thicknesses (34, 55, and 83 nm) were grown by rf sputtering at $400\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ on single-crystal ${\text{Al}}_{2}{\text{O}}_{3}$ corundum substrates showing an in-plane $\mathbf{c}$ axis. Their dynamic magnetic properties were studied using conventional and microstrip line (MS) ferromagnetic resonances (FMRs), as well as Brillouin light scattering (BLS) techniques. The effective magnetizations and gyromagnetic factors are first deduced from the resonance spectra involving the uniform magnetic mode under in-plane and out-of-plane magnetic applied fields. The angular dependence of the frequency, measured under a weak in-plane magnetic applied field, then allows deriving of the parameters describing the in-plane magnetic Anisotropy. In the 34- and 55-nm-thick films, its behavior is described assuming a magnetic energy density showing an orthorhombic symmetry with a twofold axis normal to the film and Planar Anisotropy axes at $\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}/4$ of the $\mathbf{c}$ axis of the substrate; however, due to the comparative deduced values of the pertinent coefficients, this energy density is predominantly tetragonal. In the thickest film (83 nm), one of the Planar Anisotropy axes is parallel to $\mathbf{c}$ and approximate tetragonal symmetry is no more observed. Moreover, the orthorhombic symmetry is not completely fulfilled and a small misalignment between the principal directions connected to the uniaxial and the fourfold energy terms appears. Finally, the perpendicular surface standing modes, which are observed in MS-FMR and in BLS spectra, allow evaluation of the exchange stiffness constant. Good agreement between BLS and MS-FMR measurements has been found.
G Bayreuther - One of the best experts on this subject based on the ideXlab platform.
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microstrip line ferromagnetic resonance and brillouin light scattering investigations of magnetic properties of co2mnge heusler thin films
Physical Review B, 2009Co-Authors: M Belmeguenai, F Zighem, Y Roussigne, S M Cherif, P Moch, K Westerholt, Georg Woltersdorf, G BayreutherAbstract:Co2MnGe films of different thicknesses (34, 55, and 83 nm) were grown by rf sputtering at 400 °C on single-crystal Al2O3 corundum substrates showing an in-plane c axis. Their dynamic magnetic properties were studied using conventional and microstrip line (MS) ferromagnetic resonances (FMRs), as well as Brillouin light scattering (BLS) techniques. The effective magnetizations and gyromagnetic factors are first deduced from the resonance spectra involving the uniform magnetic mode under in-plane and out-of-plane magnetic applied fields. The angular dependence of the frequency, measured under a weak in-plane magnetic applied field, then allows deriving of the parameters describing the in-plane magnetic Anisotropy. In the 34- and 55-nm-thick films, its behavior is described assuming a magnetic energy density showing an orthorhombic symmetry with a twofold axis normal to the film and Planar Anisotropy axes at ±pi/4 of the c axis of the substrate; however, due to the comparative deduced values of the pertinent coefficients, this energy density is predominantly tetragonal. In the thickest film (83 nm), one of the Planar Anisotropy axes is parallel to c and approximate tetragonal symmetry is no more observed. Moreover, the orthorhombic symmetry is not completely fulfilled and a small misalignment between the principal directions connected to the uniaxial and the fourfold energy terms appears. Finally, the perpendicular surface standing modes, which are observed in MS-FMR and in BLS spectra, allow evaluation of the exchange stiffness constant. Good agreement between BLS and MS-FMR measurements has been found.
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microstrip line ferromagnetic resonance and brillouin light scattering investigations of magnetic properties of co 2 mnge heusler thin films
Physical Review B, 2009Co-Authors: M Belmeguenai, F Zighem, Y Roussigne, S M Cherif, P Moch, K Westerholt, Georg Woltersdorf, G BayreutherAbstract:Co2MnGe films of different thicknesses (34, 55, and 83 nm) were grown by rf sputtering at 400 °C on single-crystal Al2O3 corundum substrates showing an in-plane c axis. Their dynamic magnetic properties were studied using conventional and microstrip line (MS) ferromagnetic resonances (FMRs), as well as Brillouin light scattering (BLS) techniques. The effective magnetizations and gyromagnetic factors are first deduced from the resonance spectra involving the uniform magnetic mode under in-plane and out-of-plane magnetic applied fields. The angular dependence of the frequency, measured under a weak in-plane magnetic applied field, then allows deriving of the parameters describing the in-plane magnetic Anisotropy. In the 34- and 55-nm-thick films, its behavior is described assuming a magnetic energy density showing an orthorhombic symmetry with a twofold axis normal to the film and Planar Anisotropy axes at ±pi/4 of the c axis of the substrate; however, due to the comparative deduced values of the pertinent coefficients, this energy density is predominantly tetragonal. In the thickest film (83 nm), one of the Planar Anisotropy axes is parallel to c and approximate tetragonal symmetry is no more observed. Moreover, the orthorhombic symmetry is not completely fulfilled and a small misalignment between the principal directions connected to the uniaxial and the fourfold energy terms appears. Finally, the perpendicular surface standing modes, which are observed in MS-FMR and in BLS spectra, allow evaluation of the exchange stiffness constant. Good agreement between BLS and MS-FMR measurements has been found.
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microstrip line ferromagnetic resonance and brillouin light scattering investigations of magnetic properties of co 2 mnge heusler thin films
Physical Review B, 2009Co-Authors: M Belmeguenai, F Zighem, Y Roussigne, S M Cherif, P Moch, K Westerholt, Georg Woltersdorf, G BayreutherAbstract:Co2MnGe films of different thicknesses (34, 55, and 83 nm) were grown by rf sputtering at 400 degrees C on single-crystal Al2O3 corundum substrates showing an in-plane c axis. Their dynamic magnetic properties were studied using conventional and microstrip line (MS) ferromagnetic resonances (FMRs), as well as Brillouin light scattering (BLS) techniques. The effective magnetizations and gyromagnetic factors are first deduced from the resonance spectra involving the uniform magnetic mode under in-plane and out-of-plane magnetic applied fields. The angular dependence of the frequency, measured under a weak in-plane magnetic applied field, then allows deriving of the parameters describing the in-plane magnetic Anisotropy. In the 34- and 55-nm-thick films, its behavior is described assuming a magnetic energy density showing an orthorhombic symmetry with a twofold axis normal to the film and Planar Anisotropy axes at +/-pi/4 of the c axis of the substrate; however, due to the comparative deduced values of the pertinent coefficients, this energy density is predominantly tetragonal. In the thickest film (83 nm), one of the Planar Anisotropy axes is parallel to c and approximate tetragonal symmetry is no more observed. Moreover, the orthorhombic symmetry is not completely fulfilled and a small misalignment between the principal directions connected to the uniaxial and the fourfold energy terms appears. Finally, the perpendicular surface standing modes, which are observed in MS-FMR and in BLS spectra, allow evaluation of the exchange stiffness constant. Good agreement between BLS and MS-FMR measurements has been found.
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microstrip line ferromagnetic resonance and brillouin light scattering investigations of magnetic properties of co 2 mnge heusler thin films
Physical Review B, 2009Co-Authors: M Belmeguenai, F Zighem, Y Roussigne, S M Cherif, P Moch, K Westerholt, Georg Woltersdorf, G BayreutherAbstract:${\text{Co}}_{2}\text{MnGe}$ films of different thicknesses (34, 55, and 83 nm) were grown by rf sputtering at $400\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ on single-crystal ${\text{Al}}_{2}{\text{O}}_{3}$ corundum substrates showing an in-plane $\mathbf{c}$ axis. Their dynamic magnetic properties were studied using conventional and microstrip line (MS) ferromagnetic resonances (FMRs), as well as Brillouin light scattering (BLS) techniques. The effective magnetizations and gyromagnetic factors are first deduced from the resonance spectra involving the uniform magnetic mode under in-plane and out-of-plane magnetic applied fields. The angular dependence of the frequency, measured under a weak in-plane magnetic applied field, then allows deriving of the parameters describing the in-plane magnetic Anisotropy. In the 34- and 55-nm-thick films, its behavior is described assuming a magnetic energy density showing an orthorhombic symmetry with a twofold axis normal to the film and Planar Anisotropy axes at $\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}/4$ of the $\mathbf{c}$ axis of the substrate; however, due to the comparative deduced values of the pertinent coefficients, this energy density is predominantly tetragonal. In the thickest film (83 nm), one of the Planar Anisotropy axes is parallel to $\mathbf{c}$ and approximate tetragonal symmetry is no more observed. Moreover, the orthorhombic symmetry is not completely fulfilled and a small misalignment between the principal directions connected to the uniaxial and the fourfold energy terms appears. Finally, the perpendicular surface standing modes, which are observed in MS-FMR and in BLS spectra, allow evaluation of the exchange stiffness constant. Good agreement between BLS and MS-FMR measurements has been found.
Rui Han - One of the best experts on this subject based on the ideXlab platform.
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Greatly enhanced microwave absorbing properties of Planar Anisotropy carbonyl-iron particle composites
Journal of Magnetism and Magnetic Materials, 2015Co-Authors: Liang Qiao, Tao Wang, Rui Han, Liyun TangAbstract:Abstract This paper investigates the high permeability and high resonance frequency characteristics of carbonyl-iron particle composites at microwave range. It finds that the key factor to keep both high microwave absorbing characteristics is the Planar Anisotropy. The effective permeability of Planar Anisotropy carbonyl-iron particles/nonmagnetic matrix composition in high frequency is measured and calculated. In contrast to the sphere shaped particles with no Planar Anisotropy, the permeability and resonance frequency of flake particles are greatly enhanced by introducing the Planar Anisotropy, and the permeability can be further enhanced by using a rotational orientation method to get higher Planar Anisotropy. As the use of the Planar Anisotropy, the flake soft magnetic particles increase the natural resonant frequencies so as to lead the higher real part and the imaginary part of the permeability in a broadband range. The resonance peak of flake particles is simulated by using the combination of the Landau–Lifshitz–Gilbert equation and Bruggeman’s effective medium theory, considering the correction of shape factor. Our theory simulation agrees well with the experimental data.
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greatly enhanced permeability for Planar Anisotropy ce2fe17n3 δ compound with rotational orientation in various external magnetic fields
Journal of Magnetism and Magnetic Materials, 2012Co-Authors: Rui Han, Wen-liang Zuo, Liang QiaoAbstract:A new Planar Anisotropy Ce2Fe17H3-delta compound as an electromagnetic absorption material was prepared by the arc melting method. The influence of rotational orientation in various magnetic fields on the complex permeability and orientation degrees of the compound/paraffin composites was systematically studied. It is found that the orientation plays an important role in complex permeability and orientation degrees. For the composite with rotational orientation in 1.6 T, the real permeability reaches a large value of 4.8 at 2 GHz and the imaginary part reaches 2.6 at 5.5 GHz; on the other hand, the orientation degree reaches 62.4%. It is evident that the oriented Ce2Fe17N3-delta composite with Planar Anisotropy may have potential applications as microwave absorption materials. (C) 2012 Elsevier BV. All rights reserved.
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microwave reflection properties of Planar Anisotropy fe50ni50 powder paraffin composites
Chinese Physics B, 2012Co-Authors: Jianqiang Wei, Zhaoqi Zhang, Rui HanAbstract:The reflection properties of Planar Anisotropy Fe50Ni50 powder/paraffin composites have been studied in the microwave frequency range. The permeability of Fe50Ni50 powder/paraffin composites is greatly enhanced by introducing the Planar Anisotropy, and can be further enhanced by using a rotational orientation method. The complex permeability can be considered as the superposition of two types of magnetic resonance. The resonance peak at high frequency is attributed to the natural resonance, while the peak at low frequency is attributed to the domain-wall resonance. The simulated results of the microwave reflectivity show that the matching thickness, peak frequency, permeability, and permittivity are closely related to the quarter wavelength matching condition. The Fe50Ni50 powder/paraffin composites can be attractive candidates for thinner microwave absorbers in the L-band (1–2 GHz).
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complex permeability and microwave absorbing properties of Planar Anisotropy carbonyl iron ni0 5zn0 5fe2o4 composite in quasimicrowave band
Materials Chemistry and Physics, 2012Co-Authors: Rui Han, Tao Wang, Lu-qian Gong, Liang QiaoAbstract:Abstract Planar Anisotropy carbonyl-iron (PACI)/Ni 0.5 Zn 0.5 Fe 2 O 4 composite as absorbent filler in quasimicrowave band has been synthesized via ball-milling technique and solvothermal method. The effective permeability of the composite was measured and calculated. The result indicates that the magnetic loss in the composite is mainly caused by the natural resonance. Compared with the uncoated PACI particles, the permittivity of the composite decreased dramatically, and hence a dramatic enhancement of reflection loss (RL) was obtained in quasimicrowave band. This result indicates that our PACI/ferrite composite can be used as potential microwave absorbers in quasimicrowave band for its novel microwave properties.
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Microwave complex permeability of Planar Anisotropy carbonyl-iron particles
Journal of Alloys and Compounds, 2011Co-Authors: Rui Han, Liang Qiao, Tao WangAbstract:Abstract Planar Anisotropy carbonyl-iron (PACI) particles were prepared from sphere-shaped carbonyl-iron (SSCI) materials by a simple ball milling technique. The frequency-dependent complex permeability of paraffin composites with 50% volume concentration of particles has been investigated in 0.1–18 GHz frequency range. The as-milled PACI composites show a dramatic enhancement of complex permeability and a higher resonance frequency compared with SSCI composite. This is due to the PACI particles, which have an easy magnetization plane and a thickness smaller than their skin depth, suppressing the eddy current effects. Furthermore, the complex permeability is further improved after the PACI composite was rotationally orientated in an external magnetic field. The real permeability of oriented PACI composite reaches a large value of approximate 10.5 at 0.1 GHz, and the resonance frequency shifts to a higher frequency range.