bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Nb substituted for Fe on the microstructure and magnetic properties of Fe‐based nanocomposite alloy
Authors: Hoa N. Q. , Gam D. T. H. , The N. D. , Chau N. , Son D. V. , Yu S. C. 
Published: December 2007

AbstractThe influence of Nb substituted for Fe on the microstructure and magnetic properties including the magnetoimpedance effect of a Fe‐based have been investigated. The nanocomposite structure composed of ultra‐fine Fe(Si) grains embedded in an amorphous matrix was obtained by annealing the Fe‐based amorphous alloy prepared by rapidly‐quenched method. The measurements of thermomagnetic curves indicated that the Curie temperature of the amorphous phase of the samples decreases with increasing Nb content. The optimal heat treatment was performed at Ta = 480 °C for 30 min and showed that the ultrasoft magnetic properties of nanocomposite materials were obtained. The magnetoimpedance (MI) of these samples has been studied in range frequency from 1MHz to 5 MHz and varying a dc magnetic field within 300 Oe. The correlation between the MI effect and the soft magnetic properties is discussed. The incremental permeability ratio (PR) showed the drastic changes of soft magnetic properties as a function of annealing temperatures. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In‐plane and perpendicular exchange bias in [Pt/Co]/NiO multilayers
Authors: Lin K.‐W. , Guo J.‐Y. , Kahwaji S. , Chang S.‐C. , Ouyang H. , van Lierop J. , Phuoc N. N. , Suzuki T. 
Published: December 2007

AbstractExchange bias in [Pt/Co]/NiO multilayers were studied as a function of film thickness and [Pt/Co] layer repetition. A strong temperature dependence of the coercivity, Hc, and exchange bias field, Hex, was observed for the thick and thinnest [Pt/Co]/NiO multilayers. While the thinnest [Pt(3 nm)/Co(1.25 nm)]4/NiO multilayers exhibits no in‐plane exchange bias field, a perpendicular Hex⊥ ∼ ‐150 Oe at 80 K was measured. By contrast, the thickest [Pt(12 nm)/Co(10 nm)]1/NiO multilayers exhibited an in‐plane Hex// ∼ ‐600 Oe (with Hex// ∼ ‐1300 Oe at 5 K) with no measurable perpendicular exchange bias field. The estimated interfacial exchange coupling energy implies the effective Co layer thickness contributing to the exchange bias is effective only in Co layer in contact with NiO bottom layer. AC susceptibility and the temperature dependence of Hex show that the a 1.25 nm thick Co component enables perpendicular exchange bias with a reduced blocking temperature TB∼200 K, compared to that (TB∼250 K) for the thick [Pt/Co]/NiO multilayers. This is attributed to disordered CoPt phases that formed due to intermixing between Co and Pt during deposition. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of annealing temperature on electromagnetic absorption properties of crystalline Fe‐Si‐Al alloy powder‐polymer composites
Authors: Lee Sung Jae , Kim Yoon Bae , Lee Kyung Sub , Byun Dong Jin , Kim Sang Woo 
Published: December 2007

AbstractWe investigated effect of annealing temperature on lattice strain of crystalline FeSiAl alloy powders and related electromagnetic absorption properties for crystalline FeSiAl alloy powder‐polymer composites. The lattice strain of the microforged FeSiAl alloy powder gradually decreased with annealing temperature and highly relieved by annealing treatment at 700 °C. The magnetic saturation significantly increased by the microforging and subsequent annealing treatment due to increase of the stress relaxation. The simulated power loss in the near‐field regime showed high electromagnetic absorption over 31% in above 1 GHz because of annealing effect. From simulation results of magnetic field distributions in the near‐field, the ferromagnetic metal powder‐polymer composite showed excellent electromagnetic absorption in the GHz frequency range. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Correlation between spin dependent scattering and impurity polarization in CPP‐GMR spin valves with ultra thin Cu inserted Fe‐Co layers
Authors: Isogami S. , Tsunoda M. , Noguchi K. , Nakamura T. , Osawa H. , Takahashi M. 
Published: December 2007

AbstractThe correlation between the magnitudes of spin dependent scattering (ΔRA) and impurity polarization was examined in current perpendicular to plane (CPP‐) giant magnetoresistance (GMR) films with ultra‐thin Cu inserted Fe‐Co layers, with changing the chemical compositon of Fe‐Co. The enhancing effect of ΔRA by Cu insertion was remarkable for Fe70Co30 layers in which the body centered cubic structure is maintained against Cu insertion and large spin polarization of dissolved Cu is observed via X‐ray magnetic circular dichroism. We thus conclude that the enhancement of spin dependent scattering originates from the spin polarized Cu atoms embedded in Fe‐Co alloys. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Longitudinal and transverse incremental permeability of Co19.35Fe53.28Hf7.92O19.35 films
Authors: Le Anh‐Tuan , Ha Nguyen Duy , Phan Manh‐Huong , Lee Kwang‐Eun , Kim Chong‐Oh , Lee Heebok , Yu Seong‐Cho 
Published: December 2007

AbstractWe present here, the results of a thorough study of the longitudinal permeability ratio (LPR) and transverse permeability ratio (TPR) in sputtered Co19.35Fe53.28Hf7.92O19.35 films with varying thicknesses (t = 1, 1.5, 1.8 and 2.4 µm) in the frequency range of 100 ‐ 1000 MHz. It is found that for all samples investigated, the LPR/TPR first increases with increasing frequency, reaches a maximum at 710 MHz, and then decreases at higher frequencies. This is related to the ferromagnetic resonance. The LPR and TPR profiles measured along the easy axis of the film show a single‐peak feature, whereas those measured along the hard axis of the film show a double‐peak one. This indicates an existence of magnetic anisotropy and its dispersion in the films. It reveals that the study of LPR and TPR spectra provides an alternative way for the evaluation of the high‐frequency magnetic softness of film‐type materials. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Permeability change of electroplated Ni–Fe permalloy thin films by a leveller added to the electrolyte
Authors: Bang Wonbae , Lee Jae‐Bang , Hong Kimin , Ko Young‐Dong , Chung Jin‐Seok , Lee Heebok 
Published: December 2007

AbstractWe investigated the correlation between the surface roughness and the magnetic properties in electroplated Ni–Fe Permalloy thin films. The Ni–Fe Permalloy thin films electroplated with electrolytes containing a leveling additive showed reduction of coercivity and increase of permeability compared with those prepared with pure inorganic electrolytes. The decrease of the surface roughness resulted in the reduction of coercivity and showed a strong correlation. The improvements in the surface roughness and coercivity caused the initial and incremental permeability increase by 450% and 130%, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microwave measurement uncertainty due to applied magnetic field
Authors: Perero S. , Pasquale M. 
Published: December 2007

AbstractIn recent years there has been a wide interest in the production and analysis of films and nanostructures of different types for their microwave properties up to the mm‐wave range. In order to characterize the electromagnetic behavior of these devices new experimental techniques need to be developed and assessed. Typically the measurements involve the use of vector network analyzer, and require several calibration steps. In this paper, we present a summary of the calibration techniques and evaluate the uncertainties obtained under different conditions, with a particular focus on the effect of the applied magnetic field upon uncertainty. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of synthetic conditions on iron oxide nanoparticles
Authors: Pei Wenli , Fu Y. , Kumada H. , Wang T. , Hasegawa T. , Washiya T. , Saito H. , Ishio S. 
Published: December 2007

AbstractThe magnetite nanoparticles were synthesized by different reaction conditions. The growth process of nanoparticles and influence of synthetic conditions on the particles were studied. The results show that an enough reaction time is necessary to ripen nanoparticles. However, the over‐long time leads to the deterioration of size distribution. The lower decomposition temperature is harm to size distribution. The ratio of surfactant to precursor is important for controlling nanoparticles. To attain uniform large nanoparticles, a two‐step method is reasonable method. The large iron oxide nanoparticles (up to 25 nm without agglomeration) can be produced by this method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Room‐temperature ferromagnetism of ZnO/Zn0.96Mn0.04O core‐shell nanowimble
Authors: Wang D. F. , Park S. Y. , Lee H. W. , Lee Y. S. , Lam V. D. , Lee Y. P. 
Published: December 2007

AbstractZnO/Zn0.96Mn0.04O core‐shell nanowimbles were prepared in two steps: ZnO nanowimbles were synthesized by the standard thermal evaporation method, followed by depositing Zn0.96Mn0.04O onto the surface of the prepared ZnO nanowimble using an ultrahigh‐vacuum radio‐frequency magnetron sputtering system. The scanning electron microscopy images show that the morphology, the alignment and the uniformity of ZnO/Zn0.96Mn0.04O core‐shell nanowimbles are maintained as for the as‐prepared uncoated ZnO nanowimble, and the thickness of the magnetic Zn0.96Mn0.04O layer is about 20 nm. The XRD analysis reveals that Mn is incorporated well into the wurtzite ZnO without forming Mn oxide. The magnetic property measurement shows that the ZnO/Zn0.96Mn0.04O nanowimble is in the ferromagnetic state at room temperature. The coercive field turns out to be as large as 109 Oe and 153 Oe at 300 K and 10 K, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of capping layer on the crystallization of amorphous CoFeB
Authors: Chung Ha‐Chang , Lee Young‐Ho , Lee Seong‐Rae 
Published: December 2007

AbstractWe investigated the effects of capping layer on the crystallization of amorphous top‐CoFeB electrode in the glass/CoFeB/MgO(001)/CoFeB/cap stack. Evolution of texture and crystallization of the top‐CoFeB electrode can be affected by the texture and the crystallinity of the capping layer. When the (002)‐textured Ru capping layer was used, a (110) texture of CoFeB was developed during annealing at 350 °C for 90 min. On the other hand, when the amorphous TiAl capping layer was used, a (002) texture of the CoFeB was developed during crystallization due to MgO (001) texture seeding effect. Consequently, the texture evolution of the amorphous top‐CoFeB electrode during annealing could be controlled by the texture and crystallinity of the adjacent capping layer. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An opto‐mechatronic magnetic field microsensor
Authors: Chang H. C. , Hwang C. C. , Lai C. C. , Tseng C. L. 
Published: December 2007

AbstractAn opto‐mechatronic microsensor based on fiber Bragg grating technology for sensing magnetic field strength is developed and tested. The device is fabricated using low temperature silicon‐based MEMS compatible technologies. A uniform Fe/Ni layer and embedded Fe/Ni flaps are deposited on the elastic membrane respectively that are actuated by external magnetic field for evaluating sensitivity. The Bragg wavelength shift of 0.37 nm was measured at the distance of 0.32 mm between the microsensor and a magnet with flux density of 1.12 T. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication and high frequency magnetic characterization of FeCoAl ternary thin films
Authors: Peng Yung‐Wang , Wu Fan‐Bean , Li Shandong , Kuo Cheng‐Lun , Duh Jenq‐Gong 
Published: December 2007

AbstractIntegration of ferromagnetic materials with electronic components represents a key solution to the enhancement of high frequency characteristics for recent miniaturized communication devices. In this study, Al element was introduced into FeCo binary alloy to form a ternary FeCoAl magnetic thin film by co‐sputtering technique followed by annealing in the presence of an external magnetic field. X‐ray diffraction results revealed that the FeCoAl films exhibited a solid solution microstructure of FeCo matrix with Al as the solute element. The saturation magnetization (Ms) of FeCoAl thin film still maintained a high value around 1780 emu/cm3. It was found that the FeCoAl system possessed a high permeability around 1000 and an uni‐axial anisotropic field (Hk) of 50 Oe. In addition, with the incorporation of Al element, the resonance frequency of the FeCoAl film reached 2.1 GHz. Hence, it is suggested that the FeCoAl magnetic thin film is a potential candidate for high frequency devices operated in GHz bands. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High frequency magnetic properties of Fe‐based nanocrystalline alloy powder cores
Authors: Lee Y. K. , Kim Yoon B. , Jee K. K. , Choi G. B. 
Published: December 2007

AbstractToroidal shape Fe‐based nanocrystalline alloy powder cores were prepared from the melt spun Fe73.5Cu1Nb3Si15.5B7 ribbons by cold pressing using silicon and phenol resin as an insulating material, respectively. The effect of the insulating materials and their content on the high‐frequency magnetic properties of the compacted cores were investigated. The Fe‐based nanocrystalline alloy powder cores using phenol resin exhibit stable permeability over 1 MHz, showing excellent high‐frequency characteristics. The core loss was reduced significantly and the dc‐bias property was improved by using phenol resin. Uniform and good insulation by phenol resin leads to the excellent high‐frequency characteristics of the cores. Silicon resin as an insulating material was also effective in improving the high frequency characteristics of the Fe‐based nanocrystalline alloy powder cores. However, an appropriate coating process for silicon resin should be applied in order to achieve more improved high frequency characteristics of the nanocrystalline alloy powder cores by controlling the thickness of coated layer. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and physical characterization of polyacrylamide coated magnetite particles
Authors: Hong Min Ki , Park Bong Jun , Choi Hyoung Jin 
Published: December 2007

AbstractMagnetite nanoparticles, which were synthesized by a co‐precipitation method using aqueous Fe3+/Fe2+ solution with base, were coated with polyacrylamide via inverse suspension polymerization. The fabricated particles were characterized by TEM and SEM. Ultimately, the fabricated magnetic composite particles were adopted for magentorheological (MR) fluid application. The MR properties were measured using a rotational rheometer, exhibiting that the polymer coating contributed the improvement of particle size as well as dipersion stability for applying the magnetite into the MR application. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel carbonyl iron/polystyrene (CI/PS) composites synthesized via solvent casting and their magnetorheology
Authors: Lee Mi Ah , Fang Fei Fei , Choi Hyoung Jin 
Published: December 2007

AbstractAs a magnetic material, carbonyl iron (CI) has been extensively used for magnetorheological (MR) fluids. However, MR fluids based on CI particles possess severe shortcomings of sedimentation and uniform dispersion due to the density difference between CI particles and carrier liquid. To overcome these problems, we prepared CI/polystyrene (PS) composites via a solvent casting method. The density of the synthesized CI/PS particles was much lower than that of the pristine CI particles. We further dispersed the composite particles in lubricant oil and investigated their MR properties using a rotational rheometer in parallel plate geometry with the magneto‐rheological device. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental observation of the electric coupling effect in split ring resonators and the prevention
Authors: Lam V. D. , Kim J. B. , Lee S. J. , Wang D. F. , Lee Y. P. 
Published: December 2007

AbstractWe studied experimentally the transmission properties of arrays of split‐ring resonators (SRRs) for different electromagnetic polarizations in the microwave‐frequency regime. It is known that, besides the electric response through the cut‐wire like, another electric coupling to the magnetic resonance of the SRR appears when the incident electric field is parallel to the gap‐bearing sides of the SRR. The resonance frequency of this effect is very close to the magnetic resonance. This might degrade or even destroy the left‐handed properties of the material when the SRRs are combined with the wires. To avoid this effect we have changed the structure of SRRs from an asymmetric one with a single gap to a symmetric one with two gaps. The results are also compared with the previous studies. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure and magnetic anisotropy in L10 ordered FePd thin films
Authors: Ha J. G. , Chung I. S. , Kang J. G. , An H. W. , Koh J. H. , Koo S. M. , Cho Y. H. , Park S. Y. , Jung M. H. , Kim J. G. 
Published: December 2007

AbstractEpitaxial L10 FePd (001) thin films were successfully manufactured by sputtering deposition method. The structure and magnetic properties of FePd thin films were characterized as a function of Fe compositions. It was found that the order parameter had a maximum for the stoichiometric composition, whereas the magnetic anisotropy had a maximum as the Pd content is increased to slightly above the stoichiometric composition. This indicates that the stoichiometry is directly contributed to the chemical ordering and the magnetic anisotropy. These results imply that nonstoichiometric FePd compositions, with a slight excess of Pd, may in fact be preferred for applications that require high magnetic anisotropy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coercivity enhancement of FePt (001) thin films via Ag additive
Authors: Mei J. K. , Wei D. H. , Yao Y. D. 
Published: December 2007

AbstractAdditive single and multi Ag layers of the same entire thickness into FePt films were in order to investigate the effects between different distribution of inhomogeneities on microstructure and magnetic performance of the FePt films. The large coercivity enhancement of multi Ag compared to single Ag case is due to the relative uniform impurities or misalignments that caused pinning effects on the interfaces between the Ag and FePt films. The other contributed source is from the reduction of grain/domain size and isolation of FePt nanogranular films that can be achieved by such addition and maintain (001) orientation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhanced ferromagnetic properties of diluted Fe doped ZnO with an Al co‐doping
Authors: Ahn Geun Young , Park Seung‐Iel , Kim Chul Sung 
Published: December 2007

AbstractAl‐added Zn0.99‐xFexAl0.01O (x = 0, 0.02, 0.05) powders were prepared with an annealing in an Ar atmosphere at 1200 °C. All the peaks from the X‐ray diffraction patterns of the samples belonged to the hexagonal (P63mc) lattice of ZnO, and no indication of a secondary phase was found. The lattice parameters for the Zn0.94Fe0.05Al0.01O were a0 = 3.254 Å and c0 = 5.209 Å at room temperature. The hysteresis curve for the Zn0.94Fe0.05Al0.01O at room temperature revealed a ferromagnetic phase. The temperature dependency of the magnetization curve was measured from 60 to 350 K and revealed that the Curie temperature was above room temperature. In this study we demonstrated an enhanced ferromagnetic behavior due to an electric property change with an Al co‐doping effect. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of field variation in multi‐pole magnetic components
Authors: Chiu Kuo‐Chi , Chen Chin‐Sen 
Published: December 2007

AbstractUsing traditional methods, a fine magnetic pole pitch of less than 1 mm was very difficult to achieve and a complicated magnetization system was required. A linear wire circuit pattern was designed and formed on the printed circuit board (PCB) with a periodic structure, which provides a loop allowing the current to flow in opposite directions to induce different magnetic fields among the wire circuit. Correspondingly, a multi‐pole magnetic component with a fine magnetic pole pitch of less than 1 mm was accomplished. Various multi‐pole magnetic components with different pitch sizes of 400 μm and 500 μm were fabricated to investigate the field variation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shape‐controlled synthesis of Fe nanoparticles with high‐Ms via modest‐temperature reduction method
Authors: Yang H. T. , Ogawa T. , Hasegawa D. , Takahashi M. 
Published: December 2007

AbstractTo minimize the oxidation of Fe nanoparticles, 3 to 12 nm Fe nanoparticles have been synthesized by the modest‐temperature reduction of FeCl2 in a non‐polar solvent. Trioctylphosphine oxide and oleylamine were used to avoid additional oxidation introduced by surfactants in comparison with oleic acid. The magnetic properties of Fe nanoparticles with different sizes reveal that the saturation magnetization (Ms) of larger than 8.0 nm Fe nanoparticles is over 180 emu/g at 300 K. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanical properties of spark plasma sintering Nd–Fe–B permanent magnets
Authors: Yue Ming , Cao Aili , Wang Gongping , Liu Weiqiang , Zhang Jiuxing 
Published: December 2007

AbstractNd–Fe–B based permanent magnets were prepared by both spark Plasma Sintering (SPS) and conventional sintering technique. Mechanical properties and microstructure of the magnets were investigated. Compared with conventional sintered magnet, SPS Nd–Fe–B magnet possesses better mechanical strength in terms of both impact toughness and bending strength, which have an increase of 31.0% and 44.3% from conventional magnet to SPS one, respectively. Microstructure and fracture morphology observation shows that the fracture model of the magntets changes from inter‐granular fracture of conventional sintered magnet to intra‐granular fracture of SPS magnet. The fine and uniform Nd–Fe–B main phase crystal grains and even distributed Nd‐rich phase are responsible for the improvement of mechanical properties of the SPS Nd–Fe–B magnet. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Remote temperature sensor composed of an amorphous magnetic ribbon and a low Curie temperature ferrite tube
Authors: Nakamura M. , Yoshizawa S. , Kutsuzawa N. , Kambe S. , Ishii O. 
Published: December 2007

AbstractThis paper describes the application of remote temperature sensors made of an amorphous magnetic ribbon and a low Curie temperature ferrite tube to the measurement of temperature in an arbitrary range. By combining an amorphous magnetic ribbon and a ferrite tube with a Curie temperature of 40 °C, a resonant frequency change rate of 6.3%/°C was realized in the 35 to 40 °C temperature range. Similarly, by combining an amorphous magnetic ribbon and a ferrite tube with a Curie temperature of 47 °C, a resonant frequency change rate of 4.9%/°C was achieved in the 41 to 47 °C temperature range. These values are ∼100 times larger than that of the previously reported remote temperature sensor made only of an amorphous ribbon. Therefore, this confirms that a highly sensitive remote temperature sensor can be realized in an arbitrary temperature range. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)