bluuebunny/crossref_metadata_2025 huggingface dataset:
Impfung gegen humane Papillomaviren. Eine neue Präventionsstrategie gegen Krebs
Authors: Hampl Monika
Published: December 2007

Das Humane Papillomvirus (HPV) ist das häufigste durch Geschlechtsverkehr übertragene Virus weltweit. Circa 70 bis 80 % der Bevölkerung macht in ihrem Leben die meist asymptomatisch verlaufende Infektion durch. Wird die Infektion nicht ausgeheilt, kann es zu einem Einbau der Virus‐DNA in das Wirtsgenom kommen und damit zu einer persistierenden Infektion mit Expression der beiden viralen Onkogene E6 und E7, die in den Zellzyklus eingreifen. Eine persistierende HPV‐Infektion ist eine notwendige Voraussetzung für die Entstehung des Zervix‐ und in vielen Fällen des Vulva‐ und Analkarzinoms, sowie deren Vorstufen.
Trends in der Impfstoffentwicklung. DNA‐ und zellbasierte Impfstoffe
Authors: Scherer Jürgen , Hinz Thomas , Cichutek Klaus
Published: December 2007

Für eine Reihe von Infektionskrankheiten sowohl bakterieller, parasitärer als auch viraler Genese wurde vor allem im 20. Jahrhundert eine Vielzahl von Impfstoffen entwickelt, die Impflinge erfolgreich schützen konnten. Dies führte zu einer drastisch verminderten Krankheitslast in der Bevölkerung, zu einer deutlich verringerten Säuglingssterblichkeit und zu einer Erhöhung der Lebenserwartung. Aktuell werden die globalen Bemühungen intensiviert, das Poliomyelitis‐ und das Masern‐Virus auszurotten.
Herstellung und Qualitätskontrolle von Impfstoffen. “The process is the product”
Authors: Pfleiderer Michael
Published: December 2007

Der Nutzen von Impfstoffen zur Prophylaxe von Infektionskrankheiten wurde bereits vor mehr als 200 Jahren wissenschaftlich belegt. In der Folge wurden seit den Tagen Edward Jenners, der 1798 überzeugend darstellen konnte, dass Kuhpocken am Menschen zum Schutz vor Pockenvirusinfektionen angewendet werden können, fortwährend neue oder optimierte Impfstoffe entwickelt. Dadurch haben viele der ansonsten lebensbedrohlichen viralen und bakteriellen Infektionskrankheiten heute ihren Schrecken verloren.
Die Empfehlungen der Ständigen Impfkommission am Robert Koch‐Institut. Standardimpfungen sind erstattungsfähig
Authors: Meyer Christiane , Wiese‐Posselt Miriam , Deleré Yvonne , Reiter Sabine
Published: December 2007

Impfungen gehören zu den wirksamsten, nebenwirkungsarmen und kostengünstigsten Maßnahmen des Infektionsschutzes, weshalb es von öffentlichem Interesse ist, Impfungen zum Schutz des Einzelnen, aber auch – insbesondere durch das Erreichen einer Herdenimmunität – zum Schutz von Bevölkerungsgruppen allgemein zu empfehlen.
Impfskeptiker – Impfgegner. Von einer anderen Realität im Internet
Authors: Maurer Wolfgang
Published: December 2007

Obwohl die Durchimpfungsrate in Deutschland gestiegen ist, gibt es noch genügend Impflücken, so dass impfpräventable Infektionserreger, deren Wirt nur der Mensch ist, noch weiter zirkulieren können. Zugleich sind Impfungen unter manchen wissenschaftsfernen Menschen verpönt, ja manche bekämpfen Impfungen auf das heftigste. Impfgegner sind heterogen zusammengesetzt, die härtesten Impfgegner bezweifeln, dass es überhaupt humanpathogene Viren gibt. Eltern werden von solchen Scharlatanen aufgefordert, ihre Kinder nicht zu impfen. Impfen ist jedoch medizinischer Standard, auf den alle – auch Kinder – ein Anrecht haben. Gegen ärztliche Impfgegner sollte hart durchgegriffen werden, da sie die ärztliche Sorgfaltspflicht grob verletzen, wenn sie die STIKO‐Impfempfehlungen ablehnen.
Thermal and mechanical properties of melt processed intercalated poly(methyl methacrylate)–organoclay nanocomposites over a wide range of filler loading
Authors: Tiwari Rajkiran R , Natarajan Upendra
Published: December 2007

BACKGROUND: Poly(methyl methacrylate) (PMMA)–organoclay nanocomposites with octadecylammonium ion‐modified montmorillonite, prepared via melt processing, over a wide range of filler loading (2–16 wt%) were investigated in detail. These hybrids were characterized for their dispersion structure, and thermal and mechanical properties, such as tensile modulus (E), break stress (σbrk), percent break strain (εbrk) and ductility (J), using wide‐angle X‐ray diffraction, transmission electron microscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and tensile and impact tests.

RESULTS: Intercalated nanocomposites were formed even in the presence of 16 wt% clay (high loading) in PMMA matrix. PMMA intercalated into the galleries of the organically modified clay, with a change in d‐spacing in the range 11–16 Å. TGA results showed improved thermal stability of the nanocomposites. The glass transition temperature (Tg) of the nanocomposites, from DSC measurements, was 2–3 °C higher than that of PMMA. The ultimate tensile strength and impact strength decreased with increasing clay fraction. Tensile modulus for the nanocomposites increased by a significant amount (113%) at the highest level of clay fraction (16 wt%) studied.

CONCLUSION: We show for the first time the formation of intercalated PMMA nanocomposites with alkylammonium‐modified clays at high clay loadings (>15 wt%). Tensile modulus increases linearly with clay fraction, and the enhancement in modulus is significant. A linear correlation between tensile strength and strain‐at‐break is shown. Thermal properties are not affected appreciably. Organoclay can be dispersed well even at high clay fractions to form nanocomposites with superior bulk properties of practical interest. Copyright © 2007 Society of Chemical Industry
Glyphosate‐resistant crops: adoption, use and future considerations
Authors: Dill Gerald M , CaJacob Claire A , Padgette Stephen R
Published: December 2007

BACKGROUND: Glyphosate‐resistant crops (GRCs) were first introduced in the United States in soybeans in 1996. Adoption has been very rapid in soybeans and cotton since introduction and has grown significantly in maize in recent years. GRCs have grown to over 74 million hectares in five crop species in 13 countries. The intent of this paper is to update the hectares planted and the use patterns of GRC globally, and to discuss briefly future applications and uses of the technology.

RESULTS: The largest land areas of GRCs are occupied by soybean (54.2 million ha), maize (13.2 million ha), cotton (5.1 million ha), canola (2.3 million ha) and alfalfa (0.1 million ha). Currently, the USA, Argentina, Brazil and Canada have the largest plantings of GRCs. Herbicide use patterns would indicate that over 50% of glyphosate‐resistant (GR) maize hectares and 70% of GR cotton hectares receive alternative mode‐of‐action treatments, while approximately 25% of GR soybeans receive such a treatment in the USA. Alternative herbicide use is likely driven by both agronomic need and herbicide resistance limitations in certain GR crops such as current GR cotton. Tillage practices in the USA indicate that > 65% of GR maize hectares, 70% of GR cotton hectares and 50% of GR soybean hectares received some tillage in the production system. Tillage was likely used for multiple purposes ranging from seed‐bed preparation to weed management.

CONCLUSION: GRCs represent one of the more rapidly adopted weed management technologies in recent history. Current use patterns would indicate that GRCs will likely continue to be a popular weed management choice that may also include the use of other herbicides to complement glyphosate. Stacking with other biotechnology traits will also give farmers the benefits and convenience of multiple pest control and quality trait technologies within a single seed. Copyright © 2007 Society of Chemical Industry
A risk calculator for glyphosate resistance in Lolium rigidum (Gaud.)
Authors: Stanton Rex A , Pratley James E , Hudson David , Dill Gerald M
Published: December 2007

BACKGROUND: Glyphosate resistance has been confirmed in 58 populations of Lolium rigidum (Gaud.), a major weed of crops in southern Australia. Extensive use of glyphosate in conjunction with minimal soil disturbance has been identified as high risk for resistance to that herbicide. Land managers need a simple method for rapid assessment of the risk of resistance occurring as a result of past and proposed future management practices. Modelled on risk assessment nomographs, a simple calculator for indicating the risk of evolved glyphosate resistance in L. rigidum is described.

RESULTS: The calculator uses the generations since first use and the frequency of use of glyphosate in combination with historical cultivation levels as critical factors for determining the risk of glyphosate resistance evolution. Based on the management history of a field, a land manager can graphically determine a glyphosate resistance risk for that field.

CONCLUSION: The calculator enables the farmer or the advisor to assess the risk of a weed's population becoming resistant and modify practices accordingly to manage for sustainable glyphosate use. The risk calculator could be modified for other herbicides and different weed species. Copyright © 2007 Society of Chemical Industry
Comparison of herbicide regimes and the associated potential environmental effects of glyphosate‐resistant crops versus what they replace in Europe
Authors: Kleter Gijs A , Harris Caroline , Stephenson Gerry , Unsworth John
Published: December 2007

While cultivation of transgenic crops takes place in seven of the EU member states, this constitutes a relatively limited part of the total acreage planted to these crops worldwide. The only glyphosate‐resistant (GR) crop grown commercially until recently has been soybean in Romania. In addition, large‐scale experimental European data exist for GR sugar and fodder beets, and, to a lesser extent, GR oilseed rape. These GR crops are likely to have an impact both on the use of herbicides and on the environmental impact of the latter. From the data on these GR crops, it appears that quantities of herbicides applied to GR beets are decreased while those on GR soybean are slightly increased compared with their conventional counterparts. Depending on the parameters used for prediction or measurement of environmental impacts of GR crops, generally similar or less negative impacts were observed compared with conventional crops. Favourable environmental effects of the glyphosate‐containing herbicide regimes on GR crops appear feasible, provided appropriate measures for maintaining biodiversity and prevention of volunteers and gene flow are applied. Copyright © 2007 Society of Chemical Industry
Magnetocaloric effect in as‐quenched and annealed Fe91–xYxZr9 (x = 0.5, 10) alloys
Authors: Kim K. S. , Kim Y. S. , Zidanic J. , Min S. G. , Yu S. C.
Published: December 2007

The magnetization behaviours have been analyzed for as‐quenched and annealed Fe91–xYxZr9 (x = 0, 5, 10) alloys. Samples were prepared by arc melting the high‐purity elemental constituents under argon gas atmosphere and by single roller melt spinning. These alloys were annealed one hour at 500 °C. The magnetic properties of the samples were measured by VSM. The Curie temperature increases with increasing Y concentration (x = 0 to 10). Temperature dependence of the entropy variation ΔSM was found to appear in the vicinity of the Curie temperature. The results show that annealed Fe86Y5Zr9 alloys have a greater magnetocaloric effect than that those in as‐quenched alloys. The value is ‐1.23 J/kg K at ΔH = 1.5 T for annealed alloy and ‐0.89 for as‐quenched alloy, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of buffer layers on the texture and magnetic properties of Co/Pt multilayers with perpendicular anisotropy
Authors: Kanak J. , Czapkiewicz M. , Stobiecki T. , Kachel M. , Sveklo I. , Maziewski A. , van Dijken S.
Published: December 2007

A study on the buffer layer dependence of film texture, surface roughness, and magnetization reversal mechanism in Co/Pt multilayers is presented. Four different buffers are used: (A) 10 nm Cu, (B) 5 nm Ta/10 nm Cu, (C) 5 nm Ta/10 nm Cu/5 nm Ta, and (D) 5 nm Ta/10 nm Cu/5 nm Ta/10 nm Cu. The growth of [2 nm Pt/0.5 nm Co]5/2 nm Pt on top of these buffer layers results in a large variation of film textures and surface morphologies. Samples with a Cu buffer (A) exhibit a low degree of film texture and are relatively rough. MOKE and MFM measurements on these films reveal that the magnetization reverses by the nucleation of numerous small domains due to a large dispersion of the activation energy barrier. Buffer layer structures where the first layer consists of Ta, on the other hand, result in (111)‐textured Co/Pt multilayers with a more regular surface morphology. In these samples, magnetization reversal proceeds by fast domain wall movement. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The influence of the texture on properties of IrMn spin valve magnetic tunnel junctions with MgO barrier and CoFeB electrodes
Authors: Kanak J. , Stobiecki T. , Drewello V. , Schmalhorst J. , Reiss G.
Published: December 2007

The influence of seed‐buffer layers on the texture and tunneling parameters was investigated. The spin valve magnetic tunnel junctions (SV‐MTJs) were deposited onto thermally oxidized Si wafers by magnetron sputtering in the following sequence of layers: substrate Si(100)/SiO2 47 nm/buffer layers/ Ir17Mn83 10 nm/CoFeB 3 nm/MgO 2 nm/CoFeB 4 nm/top layers. The following buffer systems have been used in order to induce different degree of the texture: (A) low textured buffer Cu 25 nm and (B) high textured buffer Ta 5 nm/Cu 25 nm. The type of buffer layers strongly influences the texture of IrMn antiferromagnetic layer and induces roughness of magnetic layers and MgO barrier. The highest TMR ratio 141% was obtained for sample with small roughness annealed in vacuum at 350 °C. A strong influence of the roughness, due to the barrier thickness fluctuations, on the resistance‐area product (RA) of the junctions is discussed. The Néel coupling field increases in case of high textured and rough layers and it becomes small for smooth interfaces. The proper design of the composition of the buffer layers allows to improve the magnetic and tunneling properties of MTJs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Feasibility study of micro‐undulator for T‐ray sources by using FEM
Authors: Jang Pyungwoo , Rhie Keungwon , Lee Byungcheol
Published: December 2007

Possibility of development of micro‐undulator utilizing perpendicular magnetic recording was explored by 2‐D FEM simulation. In the simulation FePt and CoCr layer were compared as an appropriate recording layer of the undulator. Also variation of maximum field and THD with aspect ratio and gap height were simulated so that they should be optimized in a given thickness of recording layer. From both the simulation results and Bitter patterns recorded on FePt/Fe micro‐undulator, the possibility of development of micro‐undulator by utilizing perpendicular recording technique could be confirmed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic switching instability of ultrathin magnetic films under crossing pulse fields with duration shorter than relaxation time
Authors: Han Yoonsung , Lee Sangho , Kim Sunghoon , Lee Jinwon , Kim Ahram , Hong Jongill
Published: December 2007

We have studied the magnetization switching behaviour of ultra‐thin films when we apply synchronous longitudinal and transverse pulse fields with duration shorter than relaxation time. The film was rectangular Permalloy with a dimension of 800 × 300 × 2 nm. In the case of a pulse duration of 100 ps, the switching map showed the c‐shaped switching characteristics rather than the typical quasi‐static asteroid. We found that the c‐shaped switching characteristics are associated with the abnormal switching behaviour. The abnormal switching area was also found for a pulse duration of 300 ps and even in the precessional switching region for a pulse duration of 500 ps. Our results show that the transient non‐uniform demagnetization developed by the crossing pulses is responsible for such abnormal switching behaviour, and this is supported by simulation for the elliptical film whose demagnetization field distribution is relatively uniform. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DNA electrophoresis under the gradient magnetic field
Authors: Yoshida Kohei , Ozawa Shun , Yamamoto Isao , Yamaguchi Masuhiro , Ogawa Kyohei , Takamasu Tadashi
Published: December 2007

The magnetic field effects on DNA electrophoresis have been investigated under the gradient and the homogeneous magnetic fields. The electrophoretic distance of the DNA is different between them. The increase and decrease in the electrophoretic velocity are discovered in the gradient magnetic fields. The acceralation and decceralation of DNA are observed in the negative and positive gradients of the magnetic fields, respectively. The results are discussed with the magnetic force and a new separation method of DNAs is suggested. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrasoft magnetic properties of Co–Fe–Hf–O nanocomposite films
Authors: Ha N. D. , Phan M. H. , Tuan L. A. , Phan T. L. , Kim C. G. , Kim C. O. , Yu S. C.
Published: December 2007

This paper reports on the excellent high‐frequency magnetic performance of Co–Fe–Hf–O thin films, which were deposited on Si(100) substrates by the oxygen reactive rf‐sputtering method. It was shown that the films possessed not only high electrical resistivity but also large saturation magnetization and hard‐axis anisotropy field. Among the compositions investigated, Co19.35Fe53.28Hf7.92O19.35 exhibited the ultrasoft magnetic properties of high saturation magnetization, 4πMs ∼19.86 kG, and low coercivity, Hc ∼1.5 Oe. The magnetic permeability remained almost constant up to 3 GHz and reached a maximum at the ferromagnetic resonant frequency of 4.024 GHz. These properties of this film together with a high electrical resistivity of 3569 μΩcm make it ideal for producing micromagnetic devices for high‐frequency applications. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetocaloric manganites: Progress and challenges
Authors: Phan Manh‐Huong , Yu Seong‐Cho
Published: December 2007

Magnetic refrigeration based on the magnetocaloric effect (MCE) becomes a topic of internationally current interest. This enabling technology provides several advantages (e.g. high energy efficiency, small volume, non‐pollution) over a conventional gas compression technique. It depends heavily upon the magnitude of MCE of magnetic substances that are used as working refrigerants. Therefore, current research is focused on a search for new materials that are low cost and exhibit small magnetic field‐induced large MCEs. This paper aims to review the recent developments of a new class of magnetocaloric material, namely, ferromagnetic manganites (R1‐xMxMnO3, where R = La, Nd, Pr and M = Ca, Sr, Ba, etc.). The good magnetocaloric properties of ferromagnetic manganites in addition to their flexibility and cost‐effectives make them very promising for active magnetic refrigeration (AMR) applications in the temperature range of 30–375 K. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Domain walls, domain wall transformations and structural changes in permalloy nanowires when subjected to current pulses
Authors: Hempe E.‐M. , Kläui M. , Kasama T. , Backes D. , Junginger F. , Krzyk S. , Heyderman L. J. , Dunin‐Borkowski R. , Rüdiger U.
Published: December 2007

We report the direct transmission electron microscopy observation of spin structure transformations in nanoscale Permalloy zigzag wires due to Joule heating during the injection of current pulses. This heating is sufficient to overcome the energy barriers separating the different metastable domain wall spin structures. Due to the large energy barriers these are stable and observable at room temperature by off‐axis electron holography and Fresnel imaging. The interaction between different domain walls is probed and the main pinning mechanism is determined to be the edge roughness. In addition to transformations, we also report on thermally assisted domain wall hopping between two pinning sites and structural changes that occur when the samples are subjected to even higher current pulses. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and magnetic properties of nano Ba‐hexaferrite/NiZn ferrite composites
Authors: Moon K. W. , Cho S. G. , Choa Y. H. , Kim K. H. , Kim J.
Published: December 2007

Ba‐hexaferrite and Ni0.5Zn0.5 ferrite nano composites have been successfully fabricated by a self‐propagating combustion method. Transmission electron microscopy and X‐ray diffractometer analysis showed that two ferrite phases were homogeneously distributed and the measured grain size of them around 20nm. The saturation magnetizations of the composites were revealed to be increased compared with the theoretical values. These increments of the saturation magnetization values could be explained by the exchange spring interaction between soft and hard magnetic phases. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of measurement geometry on permeability extracted by a broadband method
Authors: Cho S. G. , Kim J. , Kim I. , Kim K. H. , Yamaguchi M.
Published: December 2007

A broadband coplanar waveguide method, recognized as a simple and effective broadband permeability measurement tool, was used to measure the frequency dependent permeability of various magnetic thin films. It was revealed that measured permeability was strongly dependent on the dimension of the films and the geometry of the waveguide. This dependency was proven to result from the confinement of magnetic fields in the films by LLG equation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of an electric field‐induced stress on the magnetic properties of amorphous Terfenol‐D films deposited on PMN‐PT single crystal substrates
Authors: Kim Ju‐Hyun , Ravindranath V. , Shin Sung‐Chul
Published: December 2007

Amorphous Terfenol‐D films were deposited on piezoelectric PMN‐PT single crystal substrates in order to study the effect of an electric field‐induced stress on its magnetic properties. The stress was generated by a voltage applied across the PMN‐PT substrate by means of a bottom Au electrode and a Pt capping layer (top electrode) deposited on Terfenol‐D. Due to the inverse piezoelectric effect of the PMN‐PT substrate, the Terfenol‐D film is subjected to an isotropic planar stress. For a voltage variation from 0–90 V, an increase in the coercivity from 385 Oe to 444 Oe has been observed. This may be due to an increase in the compressive stress on the film, which is explained by a model describing the stress dependence of the domain wall pinning strength. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Different nanostructure cathode catalysts application for direct methanol fuel cell
Authors: Dipti Sharmin Sultana , Chung Uoo‐Chang , Kim Jong‐Pil , Chung Won‐Sub
Published: December 2007

Direct methanol fuel cell (DMFC) belongs to the same family of energy conversion device and the application of new hydrogen storage nanomaterials such as carbon nanotube (CNTs) supported catalysts is being addressed in an increasing industrial approach. In this present study, multiwall carbon nanotube supported Pt and Pt‐Ni nanoparticles were prepared as cathode catalysts for direct methanol fuel cell application. Transmission electron microscopy and X‐ray diffraction analyses indicated the formation of well‐dispersed Pt and Pt‐Ni nanoparticles having sizes of around 2 ∼ 4 nm on carbon nanotube. Furthermore, the electrochemical characterization by the cyclic voltammetry (CV) demonstrated that these catalysts have higher catalytic activity and the methanol oxidation reaction of the Pt‐Ni/CNTs is respectively almost similar and slightly higher than Pt/CNTs electrocatalysts. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and microwave properties of highly permeable FeCo‐based nano‐alloys
Authors: Wu Jun Hua , Kim Young Keun
Published: December 2007

We synthesized Fe and Co‐based (Fe48Co41Si3B8) alloy nanopowders by a mechanochemical technique and investigated their structure, magnetic and electromagnetic properties. The nanopowders have a bcc (A2) phase and demonstrate high magnetization with low coercivity. The analysis reveals that their magnetization process may be described by a two‐phase model. The microwave measurements performed by the coaxial method over a broad band up to 18 GHz show that the nanocomposites comprising the nanopowders possess high, broadband magnetic permeability, promising applications in electromagnetic shielding and microwave absorption. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characteristics of domain wall motion in CoFe films for GHz frequency application
Authors: Watanabe T. , Munakata M. , Ohkoshi M.
Published: December 2007

Dynamic magnetization process is studied in CoFe films for high frequency application by using a time‐resolved imaging technique. The domain wall resonance has been found at 130 kHz in a slit‐patterned Co35Fe65 film with high saturation magnetization. The domain wall mobility of 20 m/sOe was observed at the resonant frequency. The effective wall mass, the viscous damping constant, and the restoring force constant were evaluated in the Co35Fe65 film. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tendency of temperature on nano‐pillar for spin transfer torque memory
Authors: Ha Seung‐Seok , You Chun‐Yeol
Published: December 2007

This study perform numerical analysis for a Joule heated nano‐pillar system, which has a tunneling barrier, using the hot electrons' dissipation concept. The main focus was on the temperature dependence of the radius, thickness of the nano‐pillar and input power using the finite element method. The published experimental conditions were considered for the calculations. It was found that the peak temperature T (t =tp ) depends on the dimensions of the nano‐pillar and input power. Surprisingly, the increase in temperature was in the order of only 1 Kelvin. The reason for such a small increase in temperature is discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of the thermal conductivity of substrate on the temperature of nanowire for current induced domain wall motion
Authors: Ha Seung‐Seok , You Chun‐Yeol
Published: December 2007

We investigate the Joule‐heated nanowire temperature for current induced domain wall motion with a finite thickness insulator layer. The dependence of the temperature on the thermal conductivities of substrates and insulator layers, and the insulator layer thickness are studied by employing finite element method. We find that the increment of the temperature is roughly proportion to the inverse of thermal conductivity of the substrate and insulator layer. Furthermore, the increment of the temperature rises with the insulator thickness, and then saturates for the thick enough insulator layers. The results of the numerical calculations can be explained reasonably with the analytic solution for the Joule‐heated nanowire temperature, even though it is valid only for the case without an insulator layer. Our results suggest appropriate guideline for the design of the experiments. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
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

The 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

Exchange 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

We 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

The 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

We 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

We 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

In 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

The 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

ZnO/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

We 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

An 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

Integration 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

Toroidal 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

Magnetite 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

As 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

We 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

Epitaxial 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

Additive 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

Al‐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

Using 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

To 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)