jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

1 Apr 2011

Volume 109, Issue 7, Articles (07xxxx)

Issue Cover Spotlight Figure

J. Appl. Phys. 109, 071101 (2011); http://dx.doi.org/10.1063/1.3562200 (10 pages)

Otwin Breitenstein, Jan Bauer, Karsten Bothe, Wolfram Kwapil, Dominik Lausch, Uwe Rau, Jan Schmidt, Matthias Schneemann, Martin C. Schubert, Jan-Martin Wagner, and Wilhelm Warta
Enlarge Image | Read More
Page 1 of 2 Pages Return to All Sections Next Page
back to top
RSS Feeds
back to top Soft Magnetic Materials

Microwave response of FeCo/carbon nanotubes composites

Z. Han, D. Li, X. W. Wang, and Z. D. Zhang

J. Appl. Phys. 109, 07A301 (2011); http://dx.doi.org/10.1063/1.3533254 (3 pages) | Cited 2 times

Online Publication Date: 17 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Complex permittivity and permeability of FeCo/carbon nanotubes (CNTs)–paraffin composites have been investigated at microwave frequencies between 2 and 18 GHz. Percolation threshold PC of about 34 wt. % is determined in the present system by AC conductivity measurements. Microwave absorption of FeCo/CNTs–paraffin composites is enhanced when the mass ratio of the fillers approaches PC. Meanwhile, the maximum absorption shifts to thinner thicknesses and lower frequencies by increasing the filler content. The maximum absorption was found to be –37.5 dB at 11.2 GHz with a layer thickness of 8 mm in the composites with 30 wt. % FeCo/CNTs nanocomposites.
Show PACS
81.07.-b Nanoscale materials and structures: fabrication and characterization
73.40.Ns Metal-nonmetal contacts
81.16.-c Methods of micro- and nanofabrication and processing
77.22.Ch Permittivity (dielectric function)
78.70.Gq Microwave and radio-frequency interactions

Low core losses and magnetic properties of Fe85-86Si1-2B8P4Cu1 nanocrystalline alloys with high B for power applications (invited)

Akihiro Makino, Takeshi Kubota, Kunio Yubuta, Akihisa Inoue, Akiri Urata, Hiroyuki Matsumoto, and Shigeyoshi Yoshida

J. Appl. Phys. 109, 07A302 (2011); http://dx.doi.org/10.1063/1.3535169 (5 pages) | Cited 4 times

Online Publication Date: 17 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Recently, the energy crisis and the continued growth in electrical power generation strongly demand minimization of wasteful energy dissipation. Magnetic core loss (W) is the main source of energy dissipation in motors and transformers. This requires the development of soft magnetic materials with low coercivity (Hc) and high magnetic flux density (B). Fe-rich Fe85-86Si1-2B8P4Cu1 (at. %) alloy ribbons made from industrial raw materials (containing some impurities) with 6 mm in width have a heteroamorphous structure containing a large number of extremely small Fe grains (less than 3 nm), resulting from the unique effects of P and Cu addition in proper amounts. Crystallization of these alloys by annealing shows a uniform precipitation of α-Fe, leading to a uniform nanocrystallized structure of α-Fe grains, 16–19 nm in size, accompanied by an intergranular amorphous layer about 1 nm in width. The wide ribbons exhibit high B of 1.82–1.85 T (at 800 A/m), almost comparable to commercial oriented Fe–3 mass% Si alloys. Excellent magnetic softness (low Hc of 2.6–5.8 A/m, high permeability of 2.4–2.7 × 104 at 1 kHz and small saturation magnetostriction of 2.3–2.4 × 10−6) along with high electrical resistivity (0.67–0.74 μΩ m) of these alloys result in superior frequency characteristics of core losses and a much lower W at 50 Hz up to the maximum induction of 1.75 T, in comparison to the silicon steels now in practical use for power applications.
Show PACS
75.75.-c Magnetic properties of nanostructures
75.80.+q Magnetomechanical effects, magnetostriction
64.70.kd Metals and alloys
75.50.Tt Fine-particle systems; nanocrystalline materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Vv High coercivity materials

High Bs Fe84−xSi4B8P4Cux (x = 0 – 1.5) nanocrystalline alloys with excellent magnetic softness

Fanli Kong, Anding Wang, Xingdu Fan, He Men, Baolong Shen, Guoqiang Xie, Akihiro Makino, and Akihisa Inoue

J. Appl. Phys. 109, 07A303 (2011); http://dx.doi.org/10.1063/1.3535290 (3 pages) | Cited 6 times

Online Publication Date: 17 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic properties of annealed Fe84−xSi4B8P4Cux (x = 0, 0.5, 0.75, 1.0, 1.25, 1.5) soft-magnetic alloys prepared by melt–spinning were investigated. In this alloy system, the appropriate addition of the Cu element promotes the precipitation of α-Fe(Si), as well as inhibits the precipitation of other phases. The saturation magnetic flux density Bs increases and the coercivity Hc markedly decreases simultaneously with increasing Cu content until x = 1.25. The Fe82.75Si4B8P4Cu1.25 alloy annealed at 873 K for 1.8 ks shows a high Bs of 1.83 T and excellent soft-magnetic properties such as a low Hc of 2.1 A/m and a high effect permeability of 31 600. It is found that a 1%–1.25% addition of Cu is effective for the improvement of soft-magnetic properties for the present alloy system.
Show PACS
75.75.Cd Fabrication of magnetic nanostructures
81.16.-c Methods of micro- and nanofabrication and processing
81.40.Gh Other heat and thermomechanical treatments
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
81.07.Bc Nanocrystalline materials
75.50.Tt Fine-particle systems; nanocrystalline materials

Enhanced soft magnetic properties in multilayer structured amorphous Fe-Ta-C films

Debabrata Mishra, Akhilesh K. Singh, P. C. Shyni, Deepika Sharma, and A. Perumal

J. Appl. Phys. 109, 07A304 (2011); http://dx.doi.org/10.1063/1.3535417 (3 pages)

Online Publication Date: 18 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the investigation of enhanced soft magnetic properties in amorphous Fe-Ta-C thin films at larger thickness (∼200 nm), multistep magnetization reversal process and disappearance of magnetic disorder at low temperatures using [Fe-Ta-C(y)/Ta(x)]n=0−4/Fe-Ta-C(y) multilayer structured films prepared on thermally oxidized Si substrates. As-deposited films showed amorphous structure. Room temperature coercivity decreased largely from 24 Oe, for a single layer film, to 0.12 Oe, for multilayer films with n = 4 with the same total Fe-Ta-C thickness, signifying that the intervening Ta layers play a critical role in reducing coercivity. Magnetic hysteresis loops for the multilayer films with n > 2 exhibit pronounced multistep magnetization reversal processes for temperatures below 70 K depending on the number of multilayers and smooth narrow hysteresis curves for temperatures above 70 K. Low temperature thermomagnetization curves obtained under zero-field-cooled (ZFC) and field-cooled (FC) conditions showed a bifurcation between FC and ZFC data for the single layer film. With increasing the number of multilayers, the bifurcation point shifted to lower temperatures and almost disappeared for the multilayer film with n = 4. The observed results are discussed on the basis of magnetostatic interaction effects between the Fe-Ta-C ferromagnetic layers.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.50.Kj Amorphous and quasicrystalline magnetic materials
75.60.Jk Magnetization reversal mechanisms
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Dd Nonmetallic ferromagnetic materials
75.30.Et Exchange and superexchange interactions

Tunable microwave multiband filters based on a waveguide with antiferromagnetic and dielectric sandwiches

J. S. Zhang, R. L. Zhang, Qing Hu, R. H. Fan, and R. W. Peng

J. Appl. Phys. 109, 07A305 (2011); http://dx.doi.org/10.1063/1.3535440 (3 pages)

Online Publication Date: 18 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We theoretically study the propagation of hybrid electromagnetic-spin waves in a multiple-band-stop microwave waveguide, which is constructed as an antiferromagnetic (AFM1)/dielectric/antiferromagnetic (AFM2) sandwiched structure. Band stops, which are characterized by multiple attenuation peaks, have been found in the system. The frequencies of multiple band stops and the intensities of attenuation peaks can be manipulated by external magnetic field. However, by tuning the thickness of the dielectric layer or the thickness of AFM layers, the frequencies of the band stop are almost invariable, while the intensities of the attenuation peaks change significantly. This feature originates from the coupling between the microwave and spin wave associated with the collective excitations of spin motions. Our investigation may potentially be applied to the design of high-frequency microwave band-stop filters.
Show PACS
84.40.Az Waveguides, transmission lines, striplines
84.30.Vn Filters

Enhanced soft magnetic properties in magnetic field annealed amorphous Fe(Co)–Zr–B alloys

Debabrata Mishra, P. Saravanan, A. Perumal, and A. Srinivasan

J. Appl. Phys. 109, 07A306 (2011); http://dx.doi.org/10.1063/1.3533256 (3 pages)

Online Publication Date: 21 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the effects of longitudinal magnetic field annealing (MFA) on the microstructure, magnetic domain structure, and magnetic softness of Co substituted amorphous Fe89−x−yCoyBxZr11 alloys. A two-phase structure characterized by bcc Fe(Co) nanocrystals (size <15 nm) embedded in residual amorphous matrix was obtained in samples annealed below 873 K. Room temperature saturation magnetization (MS) of Fe89−x−yCoyBxZr11 alloys not only increases from 93 to 127 emu/g in the amorphous state upon Co substitution, but also enhances to 173 emu/g with MFA. Coercivity (HC) increases significantly when annealed up to 673 K and decreases slightly beyond 673 K. All samples annealed at 923 K showed large HC (>100 Oe) due to the formation of Fe(Co)–Zr compounds. Large MS (173 emu/g) and low HC (0.4 Oe) were obtained for an Fe69Co10B10Zr11 alloy annealed at 823 K. Lorentz microscopy results reveal that the average size of the domains decreases with increasing Co content and magnetic ripple structures are observed in samples annealed above 823K. The observed enhancement in magnetic softness is correlated with the microstructure and magnetic domain structure.
Show PACS
75.75.-c Magnetic properties of nanostructures
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.60.Nt Magnetic annealing and temperature-hysteresis effects
75.60.Ch Domain walls and domain structure
75.50.Tt Fine-particle systems; nanocrystalline materials
75.50.Kj Amorphous and quasicrystalline magnetic materials

Anisotropic magnetic properties and domain structure in Fe-3%Si (110) steel sheet

Sunmi Shin, Rudolf Schaefer, and B. C. DeCooman

J. Appl. Phys. 109, 07A307 (2011); http://dx.doi.org/10.1063/1.3535547 (3 pages)

Online Publication Date: 21 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The understanding of the anisotropic magnetization mechanism in 3%Si steel is relevant to both the design of the electrotechnical applications of 3%Si steel and the fundamental materials science of soft magnetic materials. In the present study, the relation between the anisotropic magnetic properties and the magnetization curves of 3%Si-Fe (110) steel sheet for various directions of axial magnetization was studied taking into account the domain structure. The magnetic loss of the (110) steel sheet were measured in an applied field at an angle α to the [001] axis. The angle α was varied from 0° to 90°, in steps of 15°. In off-[001] directions, the magnetization resulted in a highly structured domain pattern and domain wall displacements, which could be related to the shape of the magnetization curves. The magnetization curves could be divided in four segments, with each segment related to a specific domain structure.
Show PACS
75.30.Gw Magnetic anisotropy
75.60.Ch Domain walls and domain structure

Soft magnetic properties of (Ni80Fe20)1−x(Ni0.5Zn0.5Fe2O4)x films for high frequency applications

Guangduo Lu, Huai-wu Zhang, John Q. Xiao, Xiaoli Tang, Yunsong Xie, and Zhiyong Zhong

J. Appl. Phys. 109, 07A308 (2011); http://dx.doi.org/10.1063/1.3535550 (3 pages) | Cited 1 time

Online Publication Date: 21 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A series of (Ni80Fe20)1−x(Ni0.5Zn0.5Fe2O4)x films were fabricated on Si substrates by means of radio frequency magnetron sputtering and the electrical and magnetic properties were studied. Optimal films with the desired properties of low coercivity Hc ∼ 4 Oe, high saturation magnetization 4πMs ∼ 14.5 kG, and high electrical resistivity ρ ∼ 1500 μΩ cm were obtained. The permeability spectra measured shows that its natural ferromagnetic resonant frequency was about 3.4 GHz. The tested results shown that the sputtering power had an important effect on the films properties and that it can be convenient to adjust the natural ferromagnetic resonant frequency of the films.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
81.15.Cd Deposition by sputtering
68.55.at Other materials
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
73.61.-r Electrical properties of specific thin films
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Reconfigurable composite right/left-handed magnetic-metamaterial waveguide at sub-wavelength scale

Fan-Yi Meng, Kuang Zhang, Qun Wu, and Lee Jong-Chul

J. Appl. Phys. 109, 07A309 (2011); http://dx.doi.org/10.1063/1.3544485 (3 pages) | Cited 2 times

Online Publication Date: 22 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A reconfigurable composite right/left-handed waveguide loaded by magnetic-metamaterial at a sub-wavelength scale is designed and investigated. The propagating mode in the reconfigurable magnetic-metamaterial waveguide (RMMW) can be switched between the left-handed and right-handed modes by changing the position of the metamaterial in the waveguide. Such RMMWs can be widely applied in the design of novel electronic devices. Numerical simulations are carried out to verify the controllability of the RMMW. Transmission characteristics, electromagnetic field distributions, dispersion curves, and effective constitutive parameters for the RMMW are simulated. It is shown that the simulation results are in good agreement with the theoretical predictions.
Show PACS
42.79.Gn Optical waveguides and couplers
42.70.-a Optical materials

Stress tunable properties of ferromagnetic microwires and their multifunctional composites

F. X. Qin, H. X. Peng, V. V. Popov, L. V. Panina, M. Ipatov, V. Zhukova, A. Zhukov, and J. Gonzalez

J. Appl. Phys. 109, 07A310 (2011); http://dx.doi.org/10.1063/1.3535553 (3 pages) | Cited 5 times

Online Publication Date: 23 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the results of a systematic study on stress tunable absorption of glass-coated amorphous Co68.7Fe4Ni1B13Si11Mo2.3 microwires and their composites. The magnetic microwires possess good stress-impedance properties and yield a stress dependence of absorption at gigahertz frequencies. The stress compensates the reverse effect of magnetic field on absorption. There exist strong stress dependences of the effective permittivity and transmission parameters. Composite failure due to the wire damage results in a dramatic change of the sign and magnitude of effective permittivity. The double peak is identified in the stress dependence of field tunability, in contrast to the single peak for the magnetic field tunability. All these results indicate that the present composites are very promising for detecting the ambient stress levels and interrogating the structural integrity.
Show PACS
78.20.Ls Magneto-optical effects
62.20.M- Structural failure of materials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
77.22.Ch Permittivity (dielectric function)
61.43.Dq Amorphous semiconductors, metals, and alloys
75.50.Bb Fe and its alloys

Microwave properties of high-aspect-ratio carbonyl iron/epoxy absorbers

Ruey-Bin Yang and Wen-Fan Liang

J. Appl. Phys. 109, 07A311 (2011); http://dx.doi.org/10.1063/1.3536340 (3 pages) | Cited 10 times

Online Publication Date: 23 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Flake-shaped carbonyl iron (FCI) powder was prepared by ball milling spherical carbonyl iron (SCI) powder for 20 h. The thicknesses of the FCI particles were ∼0.1–0.3 μm with a diameter of ∼5–10 μm. The milling process increased the aspect ratio from ∼1 for spherical powder to an aspect ratio of ∼20–100 for flake one. The complex permittivity (ɛ′ − jɛ″) and permeability (μ′ − jμ″) were measured by the transmission/reflection method in the frequency range of 2–18 GHz for composites with various weight ratios of SCI and FCI. The results show that all ɛ′, ɛ″, μ′ and μ″ substantially increased after the milling treatment. Compared to SCI particles, the FCI particles exhibit higher permeability, higher permittivity, and better absorbing properties within the frequency test range. The magnetic loss tangent of FCI composites shows that FCI, with their large shape anisotropy, may have a higher resonance frequency and exceed the Snoek’s limit in the gigahertz frequency range. For the 50 wt. % FCI composite with a thickness of 3 mm, the reflection loss at 5.5 GHz reaches −23.0 dB.
Show PACS
77.22.Ch Permittivity (dielectric function)
81.20.Wk Machining, milling
75.30.Gw Magnetic anisotropy
84.40.-x Radiowave and microwave (including millimeter wave) technology
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Total power loss density in a soft magnetic 49% Co–49% Fe–2% V-alloy

W. Pieper and J. Gerster

J. Appl. Phys. 109, 07A312 (2011); http://dx.doi.org/10.1063/1.3537956 (3 pages)

Online Publication Date: 25 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The total power loss density of a soft magnetic alloy with wt. % 49 Co–49 Fe–2 V was investigated. Measured loss data of strip material with thickness 0.1 mm were in good agreement with the statistical loss theory that is based on separation of losses into hysteresis, eddy current, and excess contributions. As a standard reference material a low-loss 2.7 wt. % Si–Fe nonoriented electrical steel (with P = 2.25 W/kg at 1.5 T and 50 Hz at thickness 0.35 mm) was also investigated. The results indicate that the amount of excess loss is distinctly higher for the SiFe electrical steel while hysteresis loss is slightly lower. As a consequence the total loss density is lower for the CoFe alloy above a limit value of frequency that is identified for material thicknesses 0.1 mm, 0.2 mm, and 0.35 mm at several induction values. This result makes the material attractive for an increasing number of applications where energy efficiency is important. Kerr-microscopic images of the magnetic domain structure of the two materials show smaller domains of the CoFe alloy as the potential reason for the difference in excess losses.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.60.Ch Domain walls and domain structure

Synthesis of air stable FeCo nanoparticles

V. Tzitzios, G. Basina, D. Niarchos, Wanfeng Li, and G. Hadjipanayis

J. Appl. Phys. 109, 07A313 (2011); http://dx.doi.org/10.1063/1.3540387 (3 pages) | Cited 3 times

Online Publication Date: 25 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nanoparticulate FeCo alloys have been synthesized by Fe(CO)5 and Co2(CO)8 thermal decomposition in paraffin oil in the presence of oleic acid and oleyl amine. The crystal structure and morphology of the nanoparticles were confirmed by powder x-ray diffraction and transmission electron microscopy. The size and crystallinity of the particles was found to depend on the reaction conditions such as the precursors concentration, reaction time, and carbonyls injection temperature. Also the Fe/Co ratio can be easily controlled by controlling the Fe and Co carbonyls ratio. The as-made nanoparticles were annealed at 500 °C under CH4 stream in order to be protected from future oxidation. This treatment leads to the formation of a graphitic shell around the particles which also protects them from sintering. Additionally, these particles can be functionalized with 1-pyrenebutiric acid in order to be soluble in various solvents.
Show PACS
75.75.Cd Fabrication of magnetic nanostructures
81.07.Bc Nanocrystalline materials
75.50.Tt Fine-particle systems; nanocrystalline materials
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
61.66.Dk Alloys

Fe-based nanocrystalline FeBCCu soft magnetic alloys with high magnetic flux density

Xingdu Fan, Aibin Ma, He Men, Guoqiang Xie, Baolong Shen, Akihiro Makino, and Akihisa Inoue

J. Appl. Phys. 109, 07A314 (2011); http://dx.doi.org/10.1063/1.3549439 (3 pages) | Cited 5 times

Online Publication Date: 28 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this study, the magnetic properties and crystalline behavior of Fe84−xB10C6Cux (x = 0–1.3) alloys prepared by annealing the melt-spun ribbon have been investigated. A Cu element was added to this system with the aim of decreasing the coercivity because the addition of Cu clusters prior to the crystallization stimulates the nucleation of α-Fe primary crystals, which greatly influences the final microstructure. It is found that in the Fe84−xB10C6Cux alloy system, the coercivity decreases with increasing x and exhibits a minimum at around x = 1.0. When x = 1.0, the alloy exhibits excellent magnetic properties after the appropriate heat treatment with a high Bs of 1.78 T, low Hc of 5.1 A/m, and low core loss less than 4.3 W/kg at 1.0 T and 400 Hz that is about 55% of that of oriented Si-steel. These results indicate that the application of this alloy to power transformers will produce very large energy savings.
Show PACS
75.75.Cd Fabrication of magnetic nanostructures
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Tt Fine-particle systems; nanocrystalline materials
75.50.Bb Fe and its alloys
81.40.Gh Other heat and thermomechanical treatments
81.07.Bc Nanocrystalline materials

Soft magnetism and microwave magnetic properties of Fe-Co-Hf films deposited by composition gradient sputtering

Shandong Li, Ming Liu, Feng Xu, J. Lou, Zongjun Tian, Jianpeng Wu, Yi Hu, Xinle Cai, Jenq-Gong Duh, and Nian X. Sun

J. Appl. Phys. 109, 07A315 (2011); http://dx.doi.org/10.1063/1.3549584 (3 pages) | Cited 4 times

Online Publication Date: 28 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A composition gradient sputtering method was employed to deposit a series of (FexCo1-x)1-yHfy alloy films with different Fe/Co atomic ratios and Hf-doping. At Fe/Co = 70/30, the magnetically annealed (Fe0.7Co0.3)1-yHfy films with y = 0.087 – 0.124 showed a very high uniaxial anisotropy and an ultrahigh ferromagnetic resonance frequency over 7 GHz after the films were annealed at 350 °C, while at Fe/Co = 50/50, the as-deposited (Fe0.5Co0.5)1-yHfy films with y = 0.074 – 0.168 showed an excellent in-plane uniaxial anisotropy and high ferromagnetic resonance frequency over 3 GHz. These Fe-Co-Hf films deposited by the composition gradient sputtering method exhibited ahigh saturation magnetization of 1.8 – 2.2 T, a large uniaxial anisotropy field of 200 – 500 Oe, and a high ferromagnetic resonance frequency over 7 GHz, which provides great opportunities for integrated magnetic devices.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.30.Gw Magnetic anisotropy
75.60.Nt Magnetic annealing and temperature-hysteresis effects
81.15.Cd Deposition by sputtering
68.55.A- Nucleation and growth
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance

Sub-100 μm scale on-chip inductors with CoZrTa for GHz applications

Wei Xu, Hao Wu, Donald S. Gardner, Saurabh Sinha, Tawab Dastagir, Bertan Bakkaloglu, Yu Cao, and Hongbin Yu

J. Appl. Phys. 109, 07A316 (2011); http://dx.doi.org/10.1063/1.3549594 (3 pages) | Cited 1 time

Online Publication Date: 29 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
On-chip inductors with magnetic material are fabricated with complementary metal-oxide semiconductor processes. The inductors use copper metallization and amorphous CoZrTa thinfilms. Enhancements of 3.5X in inductance and 3X for the quality factor at frequencies as highas 3 GHz have been successfully demonstrated by using a continuous CoZrTa-ring structure in spiral inductors at the 100 μm scale. Further improvement of the frequency response of inductance up to 6 GHz was achieved by micro-patterning the magnetic film. The effect ofincreasing the film thickness on the performance of strip line inductors was measured and modeled. This work demonstrates significantly larger increases in inductance and quality factor atabove 1 GHz as compared to prior efforts, thereby making the added processing cost worthwhile.
Show PACS
84.32.Hh Inductors and coils; wiring
85.40.Ls Metallization, contacts, interconnects; device isolation

Loss separation in soft magnetic composites

O. de la Barrière, C. Appino, F. Fiorillo, C. Ragusa, H. Ben Ahmed, M. Gabsi, F. Mazaleyrat, and M. LoBue

J. Appl. Phys. 109, 07A317 (2011); http://dx.doi.org/10.1063/1.3554207 (3 pages) | Cited 3 times

Online Publication Date: 29 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report and discuss significant results on the magnetic losses and their frequency dependence insoft magnetic composites. Two types of bonded Fe-based materials have been characterized atdifferent inductions from dc to 10 kHz and analyzed by extending the concept of loss separation and the related statistical theory to the case of heterogeneous materials. Starting from the experimental evidence of eddy current confinement inside the individual particles, the classical losscomponent is calculated for given particle size distribution. Taking then into account thecontribution of the experimentally determined quasistatic (hysteresis) loss, the excess losscomponent is obtained and quantitatively assessed. Its behavior shows that the dynamichomogenization of the magnetization process with frequency, a landmark feature of magnetic laminations, is restrained in these materials. This results into a partial offset of the loss advantage offered by the eddy current confinement.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.78.-n Magnetization dynamics

Reducing audible noise for distribution transformer with HB1 amorphous core

Yeong-Hwa Chang, Chang-Hung Hsu, Hung-Wei Lin, and Ching-Pei Tseng

J. Appl. Phys. 109, 07A318 (2011); http://dx.doi.org/10.1063/1.3553939 (3 pages) | Cited 1 time

Online Publication Date: 30 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this paper, the way to reduce the audible noise of a distribution transformer is presented by incorporating a newly developed transformer core and a rigid-structure tank. The vibrations related tothe core structure and tank frame are considered, so that a distribution transformer with accelerometers mounted on the internal core and external tank, respectively, is addressed. In practice, the core with a new joint structure and the tank with a strong rigid-frame (H-type) are applied to a single-phase amorphous HB1-cored transformer with capacity 167 kVA for performance verification. Finally, a personal computer-based data acquisition platform is setup for signal measurement and processing. Experimental results demonstrate that the HB1 amorphous-cored transformer with the proposed core joint and rigid-structure tank can be performed well in the aspect of audible noise reduction.
Show PACS
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables
85.70.-w Magnetic devices
43.50.-x Noise: its effects and control

A balanced composite backward and forward compact waveguide based on resonant metamaterials

Qi Tang, Fan-Yi Meng, Qun Wu, and Jong-Chul Lee

J. Appl. Phys. 109, 07A319 (2011); http://dx.doi.org/10.1063/1.3554268 (3 pages)

Online Publication Date: 30 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A balanced composite backward and forward waveguide is presented by using modified split ring resonators. The forbidden band between the forward and backward guided mode is eliminated. Acoaxial feed method is proposed to excite both the forward and backward guided modes. The passband of the proposed structure ranges from 4.28GHz to 6.83GHz, below the cutoff frequency of the fundamental mode of the hollow waveguide (∼15 GHz). Physical size of the waveguide has been dramatically decreased.
Show PACS
42.79.Gn Optical waveguides and couplers
42.70.-a Optical materials

The influence of Fe content on the magnetic and electromagnetic characteristics for Fex(CoNi)1−x ternary alloy nanoparticles

S. J. Yan, L. Zhen, C. Y. Xu, J. T. Jiang, W. Z. Shao, L. Lu, and J. Tang

J. Appl. Phys. 109, 07A320 (2011); http://dx.doi.org/10.1063/1.3556762 (3 pages) | Cited 2 times

Online Publication Date: 30 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Fex(CoNi)1−x (x = 0.14, 0.20, 0.25) ternary alloy nanoparticles were fabricated by a self-catalyzed reduction method at a low temperature. The investigation of static magnetic properties revealed both saturation magnetization and coercive force enhanced with increasing Fe content. By dispersing alloy nanoparticles into paraffin matrix homogeneously, the electromagnetic properties of them were investigated experimentally and the electromagnetic absorption performances were calculated according to transmission line theory. Significant dielectric relaxation was found in the low Fe content sample, which is dominant in dielectric loss. The magnetic loss was attributed to natural resonance and the resonance peaks’ shift to high frequency region with increasing Fecontent. The enhanced electromagnetic absorption performances were obtained by adjusting Fe content to balance electromagnetic parameters, because the electromagnetic parameters can be varied by structural and magnetic properties.
Show PACS
81.07.Bc Nanocrystalline materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
77.22.Gm Dielectric loss and relaxation
75.50.Tt Fine-particle systems; nanocrystalline materials

“In-plane” and “out-of-plane” uniaxial anisotropy of amorphous precursors and nanocrystalline FeCuNbSiB alloys

G. A. Basheed, S. N. Kaul, and M. Vázquez

J. Appl. Phys. 109, 07A321 (2011); http://dx.doi.org/10.1063/1.3556936 (3 pages)

Online Publication Date: 30 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The “in-plane” and “out-of-plane” angular dependence of ferromagnetic resonance data demonstrate that both cubic and uniaxial magnetocrystalline anisotropies are present in FeCuNbSiB nanocrystalline alloys. The intergrain exchange interactions, mediated by the spins of the amorphous ferromagnetic matrix, are unable (able) to average out the local uniaxial magnetocrystalline anisotropy of the Fe3B and Fe2Si nanocrystalline grains and, thereby, lead to the magnetic hardening (softening) in the early stages of nanocrystallization in most of the compositions (remaining ones).
Show PACS
75.75.-c Magnetic properties of nanostructures
75.30.Et Exchange and superexchange interactions
75.30.Gw Magnetic anisotropy
75.50.Kj Amorphous and quasicrystalline magnetic materials

Fluxmetric-magnetooptical approach to broadband energy losses in amorphous ribbons

Alessandro Magni, Fausto Fiorillo, Ambra Caprile, Enzo Ferrara, and Luca Martino

J. Appl. Phys. 109, 07A322 (2011); http://dx.doi.org/10.1063/1.3556937 (3 pages)

Online Publication Date: 30 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetization process in field annealed amorphous ribbons has been investigated from dc to 10 MHz. Loss and permeability measurements, carried out both on single strips and ring samples by means of a broadband fluxmetric setup, have been associated with observations of the domain wall dynamics by high-speed stroboscopic Kerr apparatus. Transverse anisotropy Co-based ribbons exhibit a combination of rotational and domain wall processes, the latter being observed to progressively damp with frequency and coming to a halt on approaching the megahertz range. Given the vanishing direct contribution of the domain walls to the high-frequency magnetization process, the so-called classical loss formulation, associated with the rotational magnetization processes, is expected to correspondingly hold for the energy loss W(f). Under these conditions, W(f) tends to increase linearly with f, which, in view of the expected surge of the skin effect, does not agree with the f1/2 behavior accordingly predicted by standard formulas. This points to the specific properties of the rotational process and the role played by the exchange torque in connection with incomplete flux penetration.
Show PACS
78.20.Ls Magneto-optical effects
75.60.Nt Magnetic annealing and temperature-hysteresis effects
75.60.Ch Domain walls and domain structure
75.30.Gw Magnetic anisotropy
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Et Exchange and superexchange interactions

Ferromagnetic microstructured thin films with high complex permeability for microwave applications

J. Vernieres, J. F. Bobo, D. Prost, F. Issac, and F. Boust

J. Appl. Phys. 109, 07A323 (2011); http://dx.doi.org/10.1063/1.3560035 (3 pages) | Cited 2 times

Online Publication Date: 31 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ferromagnetic microstructured films of Ni80Fe20 with in-plane uniaxial anisotropy were prepared by RF magnetron sputtering and patterned into rectangles with the larger dimension parallel to the easy axis. Static properties have been measured using a magneto-optic-Kerr-effect test bench, and dynamic properties were also obtained in the microwave frequency range. Because of ferromagnetic resonance, high complex permeability is obtained, and this corresponds to losses that create local heating. So, at an appropriate frequency, a microwave incident magnetic field interacts with the film and generates heating. This heating is recorded using an infrared camera to provide magnetic field pattern images. This setup yields qualitative results and allows for magnetic field detection on a large dimension scale.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Bb Fe and its alloys
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Gw Magnetic anisotropy
78.20.Ls Magneto-optical effects
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance

Magnetic and electrical properties of Mn–Zn ferrites synthesized by combustion method without subsequent heat treatments

Ming-Ru Syue, Fu-Jin Wei, Chan-Shin Chou, and Chao-Ming Fu

J. Appl. Phys. 109, 07A324 (2011); http://dx.doi.org/10.1063/1.3560880 (3 pages) | Cited 4 times

Online Publication Date: 31 March 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nanocrystalline ferrites MnxZn1−xFe2O4 (x = 0.0–1.0) were prepared by the combustion method without sequential heat treatment. As-synthesized MnxZn1−xFe2O4 ferrites, characterized by x-ray diffraction (XRD), have demonstrated a highly pure phase of spinel structure. From the analysis of XRD data with Scherrer’s formula, the average crystallite size is about 27–37 nm and the lattice parameters range from 8.457 to 8.515 Å. The saturated magnetization of the Mn–Zn ferrite samples, measured by vibrating sample magnetometer, is varied with the content of manganese. The high frequency electromagnetic properties were investigated by impedance spectra methods and the conduction mechanism was also discussed. The results imply that this combustion method without further thermal treatment is relatively efficient and economical as compared to conventional methods for industrial synthesis of ferrites in high frequency electromagnetic devices applications.
Show PACS
81.07.Bc Nanocrystalline materials
61.46.-w Structure of nanoscale materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.75.Cd Fabrication of magnetic nanostructures
73.63.Bd Nanocrystalline materials
81.16.Be Chemical synthesis methods

Evolution of magnetic properties and crystallographic texture in electrical steel with large plastic deformation

M. Fukuhara, T. Yonamine, F. J. G. Landgraf, and F. P. Missell

J. Appl. Phys. 109, 07A325 (2011); http://dx.doi.org/10.1063/1.3560895 (3 pages)

Online Publication Date: 1 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Deformation leads to a hardening of steel due to an increase in the density of dislocations and a reduction in their mobility, giving rise to a state of elevated residual stresses in the crystal lattice. In the microstructure, one observes an increase in the contribution of crystalline orientations which are unfavorable to the magnetization, as seen, for example, by a decrease in B50, the magnetic flux density at a field of 50 A/cm. The present study was carried out with longitudinal strips of fully processed non-oriented (NO) electrical steel, with deformations up to 70% resulting from cold rolling in the longitudinal direction. With increasing plastic deformation, the value of B50 gradually decreases until it reaches a minimum value, where it remains even for larger deformations. On the other hand, the coercive field Hc continually increases. Magnetometry results and electron backscatter diffraction results are compared and discussed.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
79.20.Kz Other electron-impact emission phenomena
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
81.40.Lm Deformation, plasticity, and creep
62.20.fq Plasticity and superplasticity
Page 1 of 2 Pages Return to All Sections Next Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close