bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Temperature Deposition of ZnO SiO2 Thin Films on Polymer Surfaces by Plasma Enhanced CVD
Authors: Anma Hidetaka , Yoshimoto Yuuji , Tanaka Mariko , Takatsuka Hiroyuki , Hatanaka Yoshinori 
Published: April 2011

ABSTRACTZnO and SiO2 thin films coated on plastic materials were investigated for the protection against solar ultraviolet (UV) radiation and the hard coating. Using diethylzinc (DEZ) as the organic zinc material, we attempt to deposit ZnO thin films on polycarbonate (PC) resin at room temperature by the cathode deposition technique of the plasma enhanced (PE) CVD method. It was found that the rf power and the substrate temperature intensively influenced on the deposition rate. The deposition rate increased with the rf power up to 100W, but decreased with the RF power above 100W, and also decreased with increasing the substrate temperature. In a xenon arc weatherability test, the ZnO-coated PC plates exhibited remarkable protection characteristics against UV radiation. They kept a smooth surface and no- coloring even if UV light irradiated for 1000 hours. Moreover, SiO2film deposited from tetraethoxysilane (TEOS) was over-coated on the ZnO film / PC plates. These films showed a drastic improvement in the hardness. Therefore, these films are expected as the UV-cut and hard coating for the automotive parts.
Luminous efficiency of AC Plasma Display Panels with MgO–TiO2
Authors: Kim Younghyun , Kim Rakhwan , Lee Yonguk , Jung Seonghoon , Park Jong-Wan 
Published: April 2011

ABSTRACTIn order to improve both the operating voltage and the luminous efficiency of the protective layer for AC Plasma Display Panels, controlled amount of TiO2 was added to the pure MgO. The effect of the TiO2 addition on both the electrical properties (firing voltage & sustain voltage) and the luminous efficiency of the Mg2−2xTixO2 films deposited by e-beam evaporation was investigated. By addition of a proper amount of TiO2 to MgO, the dielectric constant of protective layer was increased to the 11, which has higher than that of bulk MgO. When the composition of Ti in the thin films was about 2.45at%, firing and sustain voltages were very low. With this composition, the luminous efficiency characteristics were much better than that of any other protective layer. When compared to that of the conventional MgO protective layer, the luminous efficiency showed an increase by 28%.
Microstructruture of Heteroepitaxially Grown TiO2 Films by Magnetron Sputtering
Authors: Yamagishi Makiko , Song Pung Keun , Shigesato Yuzo 
Published: April 2011

ABSTRACTTitanium dioxide (TiO2) films were deposited on (a) non-alkali glass, (b) MgO (100) and (c) SrTiO3 (100) single crystals by rf reactive magnetron sputtering using a Ti metal target. X-ray diffraction and a pole figure analysis revealed that TiO2 films on the (a) were anatase polycrystals with <101> preferred orientation, whereas heteroepitaxial growth of anatase TiO2 was observed on the (b) and the (c) substrates. FE-SEM analyses on the crystal habit of the firm surfaces showed that the substrate temperature during the deposition (Ts) heavily affected the microstructure and surface morphology of the heteroepitaxially grown films, which could be clearly explained in terms of “Thornton's zone model” or “epitaxial growth model of 2-dimensional ledge or kink modes” considering the normalized Ts by the phase transition temperature from anatase to rutile.
Growth of compound semiconductors in nanometer sized channels of polymers
Authors: Engelhardt R. , Könenkamp R. 
Published: April 2011

ABSTRACTWe report about the electrodeposition of a transparent, p-type semiconductor in etched channelsof a thin polyester foil. The embedded semiconductor columns are robust against mechanical stress exerted on the foil, as the soft polyester matrix exerts only small forces on the embedded material. Dissolving the polyester results in freestanding semiconductor columns with height-to-diameter ratios in excess of 100.
Detection of Pinholes in Ultrathin Films by Magnetic Coupling
Authors: Egelhoff W. F. , Gan L. , Chen P. J. , Powell C. J. , Mcmichael R. D. , Fry R. A. , Beach G. , Martien D. , Berkowitz A. E. 
Published: April 2011

ABSTRACTWhen two magnetic films are separated by a nonmagnetic film, pinholes in the nonmagnetic film can allow direct contact and, thereby, direct magnetic exchange coupling between the two magnetic films. We have studied this coupling by having one of the magnetic films pinned and leaving the other free to switch at low field. The pinning is accomplished with test structures based on exchange bias and synthetic antiferromagnetic layers. Since the pinning strength increases sharply at low temperatures but orange-peel coupling does not, low-temperature (77 K) measurements appear to identify whether an observed coupling arises primarily from magnetic coupling through pinholes or primarily from orange-peel roughness. Our measurements appear to indicate that the observed coupling arises primarily from magnetic coupling through pinholes for Cu films less than 2.1 nm thick and for Al2O3films less than 0.6 nm thick but primarily from roughness-induced (orange-peel) magnetostatic coupling for larger thicknesses.
Laser ablated pure non-crystalline Co thin films for inductors for ultra-high frequencies
Authors: Madurga V. , Vergara J. , Favieres C. 
Published: April 2011

ABSTRACTNon-crystalline Co thin films have been prepared by pulsed laser ablation deposition. From the M-H hysteresis loops measurements, a soft magnetic behavior is observed. Néel type magnetic domain walls are observed in the as-deposited films. The spontaneous magnetization, Ms(T = 300 K), is ≍ 860 emu/cm3. After annealing at 500 oC, Ms(T = 300 K) is ≍ 1460 emu/cm3. The extrapolated to zero K resistance decreases almost two orders of magnitude from the as deposited samples to the crystallized heated at 500 °C ones. A trilayer Co/Cu/Co has shown a real part magnetic susceptibility of 120 at 100 MHz. In the 100 MHz to 1 GHz frequency range, a perpendicular bias magnetic field increased this value up to 270, remaining almost constant for all range.
Iron Manganites Synthesis by the Soft Chemistry Method
Authors: Coradin Herve , Guillemet-Fritsch Sophie , Agnoli Fabrice , Tailhades Philippe , Rousset Abel 
Published: April 2011

ABSTRACTThe iron manganites FexMn(3−x)O4 synthesis by soft chemistry method have been studied. The main difficulty is to obtain single phase spinel with high Mn content (0.4< x < 1.3). Oxalate precursor powders of these materials with controlled shape and nanoscopic size have been prepared. The precursors are then heat treated with a H2/H2O/N2 gas mixture at low temperature. The resulting stoechiometric spinels are metastable phases with high specific surface area and are highly reactive toward oxygen. Therefore, these oxide can be oxidized in air at low temperature in order to produce mixed valence defect manganites FexMn(3−x)O4+δ with a good reproducibility on the oxygen content. Although, some problems persist for the higher Mn contents, as the oxygen partial pressure for the reduction must be controlled precisely in order to produce the stoechiometric spinel at low temperature. The development of a low temperature reduction system, with oxygen partial pressure controlled by oxygen electrochemical pumping, is in progress.
Magnetic Permeability and Relaxation Frequency in High Frequency Magnetic Materials.
Authors: Rosales M.I. , Montiel H. , Valenzuela R. 
Published: April 2011

ABSTRACTAn investigation of the frequency behavior of polycrystalline ferrites is presented. It is shown that the low frequency dispersion (f < 10 MHz) of permeability is associated with the bulging of pinned domain walls, and has a mixed resonance-relaxation character, closer to the latter. It is also shown that there is a linear relationship between the magnetocrystalline anisotropy constant, K1, and the relaxation frequency. The slope of this correlation depends on the grain size. Such a relationship could allow the determination of this basic parameter from polycrystalline samples.
Effect of Iron Substitution on the High-temperature Properties of Sm(Co,Cu,Ti)z Permanent Magnets
Authors: Zhou Jian , Skomski Ralph , Sellmyer David J. , Tang Wei , Hadjipanayis George C. 
Published: April 2011

ABSTRACTRecently, Ti-substituted Sm-Co permanent magnets have attracted renewed attention due to their interesting high-temperature coercivity. Our presentation deals with the effect of iron substitutions on the magnetic properties of the materials. X-ray diffraction shows that the investigated Sm(Co,Fe,Cu,Ti)z materials (z = 7.0 - 7.6) are two-phase magnets, consisting of 1:5 and 2:17 regions. The iron content affects both the coercivity and the magnetization. Depending on composition and heat treatment, some samples show a positive temperature coefficient of the coercivity in the temperature range from 22 °C to 550 °C. Moderate amounts of iron enhance the room-temperature coercivity. For example, the room-temperature coercivity of Sm(Co6.0Fe0.4Cu0.6Ti0.3) is 9.6 kOe, as compared to 7.6 kOe for Sm(Co6.4Cu0.6Ti0.3). At high temperatures, the addition of Fe has a deteriorating effect on the coercivity, which is as high as 10.0 kOe at 500 °C for Sm(Co6.4Cu0.6Ti0.3). The room-temperature magnetization increases on iron substitution, from 73 emu/g for Sm(Co6.4Cu0.6Ti0.3) to 78 emu/g for Sm(Co6.0Fe0.4Cu0.6Ti0.3). The observed temperature dependence is ascribed to the preferential dumbbell-site occupancy of the Fe atoms.
Advances in the Low Temperature Preparation and Structural Characterization of Lanthanum Strontium Manganite Powder
Authors: Guillemet-Fritsch Sophie , Coradin Hervé , Barnabé Antoine , Calmet Christophe , Tailhades Philippe , Rousset Abel 
Published: April 2011

ABSTRACTPerovskite oxides of formula La1−xSrxMnO3 have been obtained by the thermal decomposition of precursor powders. Two different kinds of precursors, carbonates and citrates have been prepared by low temperature, i.e., “chimie douce” technique. The careful control of the chemical and the hydrodynamic parameters during the synthesis process allows obtaining nice homogeneous and small size particles (80 nm for the ex-carbonates and 30 nm for ex-citrates). Pure perovskite phase is observed after a low temperature thermal treatment, from 550 °C. The structure of these oxides is either rhombohedral or cubic and depends on the strontium content, the temperature and the partial pressure of oxygen during the thermal treatment. The Mn-O distances and the Mn-O-Mn angles are directly related to the amount of Mn4+ content.
Observation of Patterns by Magnetic Force Microcopy in Fe-alloys with Shape Memory Effect
Authors: Silva M. I.N. da , González J. C. , Andrade M. S. 
Published: April 2011

ABSTRACTIn this study, we investigated the magnetic domains of a FeMnSiNiCr stainless steel sample using Magnetic Force Microscope (MFM). We compared the magnetic patterns obtained by scanning the sample with three coated probes with different magnetic properties: Medium magnetic moment (MM), low magnetic moment (LM), and low coercivity (LC). The probe-surface separation was varied between 25 to 300 nm in order to quantify the magnetic microstructure of the sample. A simple model for the probe-sample interaction was used to interpret the contrast change as a function of the probe-surface separation. The experiment showed that the average maximum frequency decreases with the probe-surface separation and the intensity of the frequency is the strongest for the MM probe. X ray diffraction experiments were used to identify the different phases present in the sample. The X-ray diffraction experiments together with the MFM showed that α-phase islands surrounded by a γ-phase matrix are responsible for the magnetic properties of the sample.
Phase-Change Media for High-Density Optical Recording
Authors: Borg Herman , Lankhorst Martijn , Meinders Erwin , Leibbrandt Wouter 
Published: April 2011

ABSTRACTRewritable optical-storage systems are quickly gaining market share in audio, video and data- storage applications. The development of new rewritable optical-storage formats with higher capacity and data rate critically depends on innovations made to the recording media incorporating so-called phase-change materials. These materials allow reversible switching between a low and high reflective state induced by laser heating. In this paper, we highlight phase-change media aspects as optical and thermal design, sputter-deposition, materials optimization, and the development of new recording strategies. Focus is on the speed race in optical recording.
Analysis of Multipulse Strategies for High Data Rate Phase Change Optical Recording
Authors: Sheila Aparna C. , Schlesinger T.E. 
Published: April 2011

ABSTRACTMultipulse strategies for two disk rotation velocities of the same phase change optical disk, were analyzed using simulations, at red and blue wavelengths. Results showed that at either wavelength, lower pulse duty cycles are needed at lower velocities to reduce recrystallization and higher duty cycles are needed at higher velocities. Optimal erase powers and cooling width for minimal overwrite jitter were also found.
A Novel Approach to Obtain GeSbTe-Based High Speed Crystallizing Materials for Phase Change Optical Recording
Authors: Lee Tae-Yon , Cheong Byung-ki , Lee Taek Sung , Park Sung Jin , Kim Won Mok , Lee Kyung Seok , Kim Ki-Bum , Kim Soon Gwang 
Published: April 2011

ABSTRACTA new approach is proposed to obtain fast crystallizing materials based on a conventional GeSbTe alloy for rewritable phase change optical data storage. By means of co-sputtering, Ge1Sb2Te4alloy was mixed with Sn1Bi2Te4alloy so as to form pseudo-binary alloys (Ge1Sb2Te4)1-x(Sn1Bi2Te4)x (x is a mole fraction). From structural and optical analyses of the co- sputtered and annealed alloy films, the formation of stable crystalline single phases was observed along with a Vegard's law behavior, suggesting a homogeneous mixing of the two alloys. By use of a 4 layered disk with (Ge1Sb2Te4)0.85(Sn1Bi2Te4)0.15 recording layer, a preliminary test of writing and erasing was carried out and the results were compared with the case of the disk with Ge1Sb2Te4recording layer. The (Ge1Sb2Te4)0.85(Sn1Bi2Te4)0.15 recording layer was found to yield markedly higher erasibility, especially with increasing disk linear velocity.
Microscopic studies of fast phase transformations in GeSbTe films
Authors: Detemple Ralf , Friedrich Inés , Njoroge Walter , Thomas Ingo , Weidenhof Volker , Wöltgens Han-Willem , Ziegler Stefan , Wuttig Matthias 
Published: April 2011

ABSTRACTVital requirements for the future success of phase change media are high data transfer rates, i.e. fast processes to read, write and erase bits of information. The understanding and optimization of fast transformations is a considerable challenge since the processes only occur on a submicrometer length scale in actual bits. Hence both high temporal and spatial resolution is needed to unravel the essential details of the phase transformation. We employ a combination of fast optical measurements with microscopic analyses using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The AFM measurements exploit the fact that the phase transformation from amorphous to crystalline is accompanied by a 6% volume reduction. This enables a measurement of the vertical and lateral speed of the phase transformation. Several examples will be presented showing the information gained by this combination of techniques.
Super-Resolution Readout for Magneto-Optical Disk by Optimizing the Deposition Condition of Non-Magnetic Mask Layer
Authors: Shima Takayuki , Kim Johoo , Fuji Hiroshi , Atoda Nobufumi , Tominaga Junji 
Published: April 2011

ABSTRACTSuper-resolution near-field structure (Super-RENS) was prepared by a heliconwave-plasma sputtering method to improve the disk property that is combined with a magneto-optical (MO) recording disk. Antimony and silver-oxide mask layers were prepared by the method and refractive indices were measured. Recording and retrieving of signals beyond the resolution limit (<370 nm) were achieved for both mask cases. Attempts to optimize the disk structure were also made using a conventional sputtering method. The smallest mark size was around 200 nm and the highest carrier-to-noise ratio (CNR) was 30 dB for 300-nm mark and 22 dB for 250-nm, when using a laser wavelength of 780 nm and a numerical aperture of 0.53. We have found that there is a competing super-resolutional mechanism besides Super-RENS that appears when high readout laser power is applied. This mechanism played rather an important role at least in the mark-size range of 200-370 nm.
Materials Development for Thermally-Assisted Magnetic Recording Media
Authors: Brucker C.F. , McDaniel T.W. 
Published: April 2011

ABSTRACTWe have carried out a combined experimental and computer simulation study to specify and identify candidate films to support high areal density, thermally-assisted magnetic recording. The motivation of this work is to utilize the enhanced writability of very high coercivity materials that thermal assistance can provide. Media with high coercivity (and anisotropy Ku) are known to be essential to achieve a sufficiently high ratio of KuV/kBT necessary to maintain magnetic stability at temperature T in media switching units (grains; single domains) of volume V. Nominally, we expect V ∝ D−3/2, where D is the medium bit density per unit area in recording. A micromagnetic recording simulation tool with a capability of representing realistic grain size distributions, temperature-dependent magnetic properties, and spatially-varying imposed temperature distributions was employed to study the interplay of thermal and magnetic field gradients in the recording process. In addition, a simple LLG-based thermomagnetic switching model supplemented the micromagnetics model. We fabricated improved Co/X multilayer media for recording evaluation, and performed standard materials characterization.
Integrated Surface Emitting Laser Arrays with Flat-Tip Microprobes for the Near-Field Optical Data Storage
Authors: Kim Young-Joo , Ye Shu-Ying , Suzuki Kazuhiro , Goto Kenya 
Published: April 2011

ABSTRACTCurrent optical data storage is challenging to increase its memory capacity and data transfer rate for realizing high-quality image and rapid service in the coming digital, multimedia and network era. To actualize more effective and simple data storage, a novel parallel near-field optical system has been proposed using vertical cavity surface emitting laser (VCSEL) microprobe arrays. The new parallel optical system is based a multibeam recording head consisting of a VCSEL array with apertures of nanometer size as a near-field wave exit. We have developed some candidates for the parallel recording head, including the direct aperture formation on the VCSEL emitting surface and the preparation of microprobe arrays with flat-tip structure. The new flat-tip microprobe array has advantages for improving the optical efficiency and stabilizing the contact head system with optical media since it is prepared from semiconductor materials of high refractive index. Silicon nano-aperture probe array has been prepared successfully with the aperture size of 150 to 500nm using micro-fabrication techniques. We have also investigated the integrated microprobe array by the direct fabrication of flat-tip probes on the substrate of bottom emitting VCSEL arrays. Finally the reading mechanism has been studied theoretically using a finite difference time domain (FDTD) simulation and an optical feedback effect of semiconductor lasers for the integrated microprobe VCSEL array. We believe this nano-aperture VCSEL probe array is sufficiently effective to be applied to the parallel recording head for the near-field optical data storage of a high data capacity and fast transfer rate.
Human Brain Like Memory Behavior in the Magnetic Domain Expansion Type Magneto-Optical Disk
Authors: Ota Norio , Awano Hiroyuki , Tani Manabu , Imai Susumu 
Published: April 2011

ABSTRACTMagnetic Amplifying Magneto-Optical System (MAMMOS) shows human brain like memory behavior. Magnetic field and laser power have threshold to recover the stored memory like the human response of remembering. MAMMOS also has a feature to amplify very small recorded signals like our recovery of memory, e.g. fifty years ago episode.By adding the meaningful information on the magnetic field pattern, we can get some correlation between our memory and external stimulation. Such scheme is named as “the Active readout MAMMOS” which is analogues to the human process of remembering the memory.If the applied field pattern and timing phase just coincide with stored information, there occurs the coherent amplification of MAMMOS signal. We can utilize such phenomena as the trigger of “Memory Association”.
Chiroptical Molecular Memory of Amorphous Azopolymer using Light Handedness
Authors: Kim Mi Jeong , Kim Dong-Yu 
Published: April 2011

ABSTRACTFor chirooptic molecular memory system, induced chirality on an azobenzene-containing amorphous polymer film was investigated using circularly polarized Ar+ laser with various ellipticity. High intense CD spectrum proved that optical-induced chirality on the amorphous film. Additionally, elliptically polarized light induced much higher chirality than circularly polarized light.
C60Clusters Self-Assembly in One-beam Optical Trap
Authors: Eugene Collins W. , Lu Weijie , Morgan Steven , Zavalin Andrey 
Published: April 2011

ABSTRACTC60aggregated clusters up to 20 um length were created on a glass surface within a solution inside of a gradient one-beam optical trap. It was possible to grow rod-shaped structures by motion of an optical trap parallel to the surface of the substrate. After the deposited structures became stable, the solution was dried. By AFM measurements of the stable dried structures, it was shown, that aggregations have typical sizes of 5–15 um X 1.5–2 um, and thickness near 1.5 um. The aggregations consist of thinner (30–100 nm diameter) rods, bundled together.
Effect of Metal Back Contacts on Tetrahedral Amorphous Carbonc Films Grown Using the Cathodic Arc Process.
Authors: Satyanarayana B.S. , Takahashi H. , Narusawa T. , Hiraki A. 
Published: April 2011

ABSTRACTReported here is a study on the effect of different metal back contacts onthe electrical and structural properties of the tetrahedral amorphous carbon (ta-C). The films were grown using a pulsed cathodic arc system. Ta-C films were deposited simultaneously on silicon substrate, precoated with the following metals, namely aluminium (Al), gold (Au), chromium(Cr), molybdenum (Mo), copper (Cu), tungsten (W) and titanium(Ti). The electrical measurements and Raman response show that the back contact does influence the properties of ta-C films. These results are analysed with respect to our earlier report regarding the influence of back contacts on field emission from similar ta-C films.
X-Ray Reflectivity of Ultra-Thin Diamond-Like Carbon Films
Authors: Tanner B. K. , LiBassi A. , Ferrari A. C. , Robertson J. 
Published: April 2011

ABSTRACTGrazing incidence x-ray reflectivity has been employed to investigate ultra-thin films of tetrahedral amorphous carbon (ta-C) grown with an S-bend filtered cathodic vacuum arc. The results indicate that x-ray reflectivity can be used as a metrological tool for thickness measurements on films as thin as 0.5 nm, which is lower than the range required for carbon overcoats for magnetic hard disks and sliders if they are to reach storage densities of 100 Gbits/in2. The density of the films was derived from the best-fit to simulated reflectivity profiles from models for the structural parameters. In such thin films, the x-rays are reflected mainly at the film substrate interface, rather than the outer surface, so that the film density is derived from analysisof the oscillations of the post-critical angle reflectivity.