bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic Anisotropy and Rotational Hysteresis Loss in Epitaxial TbFe2(110) Films
Authors: Wang Chuei-Tang , Khanna Gaurav , Clemens Bruce M. , White Robert L. 
Published: April 2011

ABSTRACTThe effect of in-plane strain on the magnetic anisotropy of [110]-oriented epitaxial TbFe2 films was studied. DC magnetron cosputtering was used to grow epitaxial TbFe2(110) films on A12O3(1120) substrates with an epitaxial Nb(110) buffer layer. Torque magnetometry showed that the films had uniaxial anisotropy, and the torque curves were used to determine the magnetic anisotropy constants of the films by analyzing the rotational hysteresis loss. Film strain was measured using synchrotron radiation. The film strain and anisotropy measurements confirm that the uniaxial anisotropy results from tensile strain in the TbFe2(110) films. This agrees with theoretical calculations of magnetic anisotropy which show that tensile strains can induce a uniaxial anisotropy in TbFe2(110) films.
Magnetic Domain Imaging with a Photoemission Microscope
Authors: Schneider C.M. , Frömter R. , Ziethen C. , Swiech W. , Brookes N.B. , Schönhense G. , Kirschner J. 
Published: April 2011

ABSTRACTPhotoelectron emission microscopy (PEEM) has proven to be a versatile analytical technique in surface science. When operated with circularly polarized light in the soft x-ray regime, however, photoemission microscopy offers a unique combination of magnetic and chemical information. Exploiting the high brilliance and circular polarization available at a helical undulator beamline, the lateral resolution in the imaging of magnetic domain structures may be pushed well into the sub-micrometer range. Using a newly designed photoemission microscope we show that under these circumstances not only domains, but also domain walls can be selectively investigated. The high sensitivity of the technique yields a sizable magnetic contrast even from magnetic films as thin as a fraction of a single monolayer. The combination of chemical selectivity and information depth is successfully employed to investigate the magnetic behavior of buried layers and covered surfaces. This approach offers a convenient access to magnetic coupling phenomena in magnetic sandwiches.
Angle- and Temperature- Dependent Magnetic Circular Dichroism in Gd(0001) Core-Level Photoemission
Authors: Morais J. , Denecke R. , Ynzunza R. X. , Menchero J.G. , Liesegang J. , Fadley C. S. 
Published: April 2011

ABSTRACTRecent results on the dependence of the magnetic circular dichroism on the angle and temperature for thick (100 ML) films of Gd(0001) are presented. Strong dichroic effects were observed in 4d core-level photoemission for the magnetized films, which showed excellent agreement with an atomic many-particle description recently published [1]. The angular dependence of the magnetic dichroism has been discussed taking into account photoelectron diffraction effects. In addition, an indication of a higher surface Curie temperature has been observed in the temperature- dependent measurements.
Spin Reorientation in Fe/Cu(100) and Cu/Fe/Cu(100)
Authors: Mentz E. , Bauer A. , Weiss D. , Kaindl G. 
Published: April 2011

ABSTRACTIn-situ scanning tunneling microscopy (STM). magneto-optical Kerr effect (MOKE) and Kerr microscopy are used to investigate the relations between structure, morphology, and magnetism in low-temperature (LT) grown Fe/Cu(100) films. At the spin reorientation thickness of ≈ 3.8 monolayers (ML) Fe/Cu(100) the coexistence of in-plane and out-of-plane magnetized domains is observed. For Fe thicknesses between 3.8 and 6 ML Fe/Cu(100). an irreversible spin reorientation from in-plane to out-of-plane can be induced by annealing up to 420 K. Annealing of LT-grown Fe/Cu(100) films is proposed to provide smooth surfaces for Cu/Fe/Cu(100) sandwich preparations.
Fe-Cr-N Based Nanocrystalline Soft Magnetic Thin Films
Authors: Zhu W. , Tiefel T. H. , Jin S. , Van Dover R. B. , Korenivski V. 
Published: April 2011

ABSTRACTWe have investigated the soft magnetic properties of new Fe-Cr-Ta-N and Fe-Cr-Hf-N alloy films. Thin films with compositions in the range of Fe-2∼8%Cr-0∼l%Ta (or Hf)-5∼10%N (in atomic %) were prepared by reactive sputtering in a nitrogen-containing atmosphere. The films, most likely nanocrystalline, exhibit excellent soft magnetic properties in the as-deposited condition without any post-deposition heat treatment, e.g., Hc∼l-2 Oe and 4πMs∼15–20 kG. The magnetic properties are highly anisotropie in the film plane as the easy-axis M-H loop is square and the hard-axis loop is linear and closed, with the anisotropy field Ha=20–100 Oe. The films exhibit excellent high frequency behavior even in the GHz frequency range which is attributed to the combination of high 4πMs and relatively high Ha.
Structural and Magnetoresistance Studies of Ni/Co Multilayers
Authors: Freitag J.M. , Ström-Olsen J.M. , Altounian Z. , Cochrane R.W. 
Published: April 2011

ABSTRACTA study of ferromagnetic/ferromagnetic Ni/Co multilayers grown by DC magnetron sputtering with component layer thicknesses between 40 and 5 Å is presented. Structural characterization by small-angle x-ray reflectivity reveals high-quality layered structures with a well-defined composition modulation along the film growth direction. Quantitative interpretation of the superlattice structure parameters, including interface roughness and intermixing, has been performed by modelling the x-ray reflectivity data. Measurements of the magnetotransport properties of these multilayers indicate that the magnetoresistance (MR) effect, Ap ∼ 0.35 μΩ-cm, is roughly constant over the entire compositional range. We attribute the origin of this effect to anisotropie magnetoresistance (AMR). The MR ratio Ap/p, which is as high as 3.0% in a SiO2/(Ni40Å/Co5Å)×6 multilayer with saturation field ∼ 80 Oe, is therefore more strongly dependent on the zero-field resistivity. By fitting a semi-classical model of conduction in multilayers to the resistivity thickness variation, we extracted the mean free paths for conduction in each of the constituent layers as well as the contribution of interfacial scattering in the superlattice structure.
Effects of Symmetry on Circular and Linear Magnetic Dichroism in Angle-Resolved Photoemission Spectra of Gd/Y(0001) and Fe-Ni/Cu(001)
Authors: Goodman K.W. , Tobin J.G. , Schumann F.O. , Willis R.F. , Gammon J.W. , pappas D.P. , Kortright J. , Denlinger J.D. , Rotenberg E. , Warwick A. , Smith N. 
Published: April 2011

ABSTRACTWe have observed circular and linear magnetic dichroisms in angle-resolved photoemission spectra of 50-monolayer Gd films grown on Y(0001) and 6-monolayer Fe-Ni alloy films grown on Cu(001). The 4/level of Gd and the Fe 3p level of the Fe-Ni alloy were measured. A different geometry was used for the magnetic circular dichroism than was used to measure the magnetic linear dichroism. The geometries were chosen so that the magnetic circular dichroism is predicted to be closely related to the magnetic linear dichroism for four-fold symmetric Fe-Ni/Cu(001) but not for three-fold symmetric Gd-Y(0001). Experimental results are presented.
Scanning Auger Microscopy Characterization of Magnetic Hard Disc
Authors: Harris D. W. , Neiman D. L. , Huang J. 
Published: April 2011

ABSTRACTApplications of Zalar rotation and field emission Auger (FE-AES) analysis in various magnetic hard disc problems will be presented. These applications include thin layer structure characterization, low concentration contaminant (0.1–0.5 atomic percent) detection at deeper interfaces (greater than 1000Å), and small particle (-∼1000Å) contaminant identification.
The Processing and Characterization of Hybrid Silica-Based Xerogel Films
Authors: Chow Loren A. , Yu Ted , Dunn Bruce S. , Tu K. N. , Chiang Chien 
Published: April 2011

AbstractHybrid organic-inorganic xerogel films were deposited as porous thin films by spinning the precursor sol on silicon substrates. Films of various compositions were prepared using combinations of the following precursors: methyltrimethoxysilane, dimethoxydimethylsilane and tetramethoxysilane (TMOS). The hybrid films exhibited excellent gap-filling capabilities (0.45 micron trenches). Thermal desorption experiments indicate that heating to ∼130 C removes moisture and volatile organic constituents present in the as-cast film. Curing was found to increase the adhesion between the xerogel and the silicon substrate. Moisture was found to be responsible for an increase in the dielectric constant. That is, in ambient, the dielectric constant for a cured film was found to be 4.4; but in a dry atmosphere, it decreased to 2.5. Current-voltage measurements show the cured hybrid film possesses a breakdown field of 3.4 MV/cm.
Low-K Dielectric Material Chemical Mechanical Polishing Process Monitoring using Acoustic Emission
Authors: Tang Jianshe , Unger Carsten , Moon Yongsik , Dornfeld David 
Published: April 2011

AbstractLow-k dielectric material removal rate, which is significantly affected by process factors such as polishing load, wafer carrier rotation, platen rotation speed and pad age, is one of the critical issues in CMP planarization of a dielectric film when concerning productivity, throughputs and stabilization of the process, especially when trying to achieve a target polishing thickness. Scratching is another critical issue in low-k dielectric filmi CMP planarization due to the lower hardness relative to silicon dioxide. This research relates to a methodology for in-situ monitoring of the low-k dielectric material CMP planarization process, specifically for monitoring material removal rate and scratch occurrence, using acoustic emission (AE) sensing technology.Systematic investigations of CMP process variables on AE signals were carried out in this research. The sensitivity of AE to polishing load, polishing speed, wafer surface roughness (wafer pattern density) and pad roughness were verified. The results showed that, under steady state, the AE rms signal increases with increasing polishing load, polishing speed, slurry particle size, wafer surface roughness and pad roughness.Based on the research in tribology and other application fields of loose abrasive machining such as lapping and polishing, scratching was known to be caused by the presence of particles which are much larger than average slurry particles. It has been proven that scratching can be avoided or reduced by timely cleaning the slurry supply system. Therefore, to avoid scratching, one strategy is to develop an in-situ method for detecting larger particles involved in CMP process. In this paper, the high sensitivity of AE signals to the presence of larger particles during CMP was experimentally verified.
The Effect of Deposition Conditions on the Properties of Vapor-Deposited Parylene AF-4 Films
Authors: Plano M. A. , Kumar D. , Cleary T. J. 
Published: April 2011

AbstractOne potential low dielectric constant material for ULSI multilevel interconnect applications is parylene AF-4, an organic polymer more formally known as Poly (α, α, α’, α’ - tetrafluoro-p-xylylene). In this study parylene AF-4 films were vapor-deposited on silicon wafers by pyrolytic decomposition of the cyclic dimer, cyclodi(α, α, α’, α’ - tetrafluoro-p-xylylene) using four different deposition conditions. Two different wafer temperatures and two different vaporizer temperatures were used, while the chamber pressure was kept constant. High vaporizer temperature and low wafer temperature give the highest deposition rates. It was found that the surface roughness of films of similar thickness showed a dependence on the deposition conditions. The films deposited at a low vaporizer temperature exhibit a smooth surface (RMS ∼ 4 nm) while those deposited at high vaporizer temperature have a rougher surface (RMS ∼ 16 nm). However, other properties of the films remained very similar. The FTIR spectra and refractive indices, both TE and TM, were measured for the films deposited using the four different deposition processes and showed no dependence on deposition conditions. These results indicate that the change in surface roughness is not due to a large difference in the chemical bonding among the films deposited using the four processes. Also, both weight loss and thickness loss of the films were measured after thermal cycling the films to 450°C and no significant differences were observed. This result indicates that the observed increase in surface roughness with increased vaporizer temperature cannot be related to a change in dimer incorporation in the films. Further experiments are planned to investigate the role of the initiation stage of the polymerization on film surface morphology.
Low Dielectric Constant Fluorine Doped Teos Films
Authors: Rana Viren V. S. , Bhan Mohan , Gupta Anand , Hong Soonil , Lee Peter 
Published: April 2011

AbstractThe fluorine doped TEOS films obtained using an inorganic gaseous dopant source (SiF4) and an organic liquid dopant source (TEFS) are described. The stability of fluorine in these films is strongly dependent on process conditions. The limit of stability for the most stable films is described. The gap fill capability of these films was found to depend strongly on the type of the fluorine precursor.
Sidewall Quality and Step Coverage of Thin Fluorosilicate Glass Films
Authors: Weise Mark T. , Selbrede Steven C. 
Published: April 2011

AbstractThe quality of TEOS fluorosilicate glass (FSG) films deposited on deep silicon trenches was investigated by etching the films with 100:1 HF. The etch rate of the top and sidewall surfaces was measured by SEM as a function of FSG fluorine content. The FSG wet etch rate was correlated to the refractive index, stress and fluorine content. The sidewalls were found to etch slower than the top surfaces, suggesting a lower fluorine content on the sidewalls. Additionally, the step coverage of TEOS oxide improved significantly as fluorine content was increased.
The Influence of Fluorine Desorption from ECR-CVD SiOF Film
Authors: Usami Tatsuya , Ishikawa Hiraku , Gomi Hideki 
Published: April 2011

AbstractThe influence of fluorine desorption from SiOF films deposited by biased ECR-CVD was studied. It was found that desorbed F atoms from the SiOF film react with Ti suicide film resulting in forming SiF4 gas. The evolution of SiF4 gas caused the peel-off of the films.
A Detailed Procedure for Reliable Preparation of Tem Samples Using Fib Milling
Authors: Su D. H.-I , Shishido H. T. , Tsai F. , Liang L. , Mercado F. C. 
Published: April 2011

AbstractAlthough many publications have discussed focused ion beam (FIB) preparation of TEM samples, few have presented a detailed, step-by-step milling procedure. This is a summary of techniques that evolved over the past 3 years in our laboratory. In addition to describing more traditional mechanical pre-thinning techniques, we introduce a method to pre-thin samples down to thicknesses of the order of 20 μm within 1 hour using a wafer dicing saw. We then discuss different ways to handle mechanically difficult samples such as those prone to delaminate. Our approach to FIB milling is designed to minimize the effects of ion-beam spreading which is responsible for most of the failures to prepare good FIBTEM samples. The technique is presented in a step-by-step fashion including a simple yet reliable method to terminate FIB milling. Examples are shown to illustrate applications to different types of problems including - precision cross-sectioning of integrated circuit (IC) devices, cross-sectioning of samples prone to delamination, and cross-sectioning of specific defect sites. Finally, we discuss the effect of artifacts in the quality of TEM samples.
Focused Ion Beam Milling and Micromanipulation Lift-Out for Site Specific Cross-Section Tem Specimen Preparation
Authors: Giannuzzi L. A. , Drown J. L. , Brown S. R. , Irwin R. B. , Stevie F. A. 
Published: April 2011

AbstractA site specific technique for cross-section transmission electron microscopy specimen preparation of difficult materials is presented. Focused ion beams are used to slice an electron transparent sliver of the specimen from a specific area of interest. Micromanipulation lift-out procedures are then used to transport the electron transparent specimen to a carbon coated copper grid for subsequent TEM analysis. The experimental procedures are described in detail and an example of the lift-out technique is presented.
A New Procedure for Making Tem Specimens of Superconductor Devices
Authors: Huang Y. , Merkle K. L. 
Published: April 2011

AbstractA new procedure is developed for making TEM specimens of thin film devices. In this procedure the sample is flatly polished to an overall “ion-mill-ready” thickness so that any point in the 2-D sample plane can be thinned to an electron-transparent thickness by subsequent ionmilling. Using this procedure small regions of interest can be easily reached in both cross-section and plan-view samples. This is specially useful in device studies. Applications of this procedure to the study of superconductor devices yield good results. This procedure, using commercially available equipment and relatively cheap materials, is simple and easy to realize.
An Updated Ion Polishing System for Tem Specimen Preparation of Materials
Authors: Alani R. , Mitro R. J. , Swann P. R. 
Published: April 2011

AbstractThe construction and performance of an improved ion milling instrument are described. The updated instrument is based upon an earlier version fixed low angle ion milling system. The updated system employs two improved guns having the ability of independent variable milling angle adjustment, while operating at high voltage in the vacuum system. The milling rate of these ion guns is typically ≈ 90μm/hr/gun pair for copper at 5keV and 10°. Designed to compliment the variable angle ion gun is a new specimen holder which permits low angle double sided milling. The combination of these two features offers numerous single or double sided milling conditions to facilitate the production of higher quality TEM specimens in less time. The range of ion gun angles encompassed is 0° to 10° for single-sided milling and 0° to ± 10° for double-sided milling. The instrument also incorporates an electronic mechanism to generate directional sector milling which benefits primarily the production of cross sectional TEM specimens and heat sensitive materials since the ion guns are turned off for a portion of time during each revolution. Another new feature of the instrument is chemical ion milling which facilitates the preparation of certain compound semiconductors. The ability of this improved ion milling instrument for rapid ion polishing and improved specimen quality is demonstrated by a number of TEM images of metals, ceramics and semiconductors.
Subcritical Bifurcation from Planar to Cellular Interface in Al – 0.5 wt.% Cu Directionally Solidified
Authors: Fornaro O. , Palacio H. , Biloni H. 
Published: April 2011

ABSTRACTSamples of the Al – 0.5wt.% Cu system were directionally grown under controlled conditions, to study the role played by the instabilities in the process relatives to the microstructure selection for a given values of interface velocity, and thermal gradient. Using an interface quenching technique and metallographic analysis in longitudinal and transversal cuts of the samples, we determine the transition mechanisms between the different stages of the growth, and associate them to the stability of the solidification front. We study the planar to a cellular transition in different conditions, and although the solidification parameters are in good agreement with the perturbations theory, when analyzing the amplitude of the perturbations during the planar to a cellular transition, the same theory is not able to predict certainly the critical wavelength in this case. Also, we found a subcritical behavior during the transition from a planar to a cellular interface for the diluted Al – Cu system, detecting a hysteresis behavior for the amplitude of the perturbations when it is increasing and then decreasing the interface velocity, through the threshold.
Shape Evolution and Splitting of a Single Coherent Particle
Authors: Zhang J. D. , Li D. Y. , Chen L. Q. 
Published: April 2011

ABSTRACTThe morphology and its evolution of a single coherent precipitate was investigated using the Cahn-Hilliard equation and Khachaturyan's continuum elasticity theory for solid solutions. A cubic solid solution with negative elastic anisotropy and isotropic interfacial energy was considered. The lattice mismatch between the precipitate and the matrix was assumed to be purely dilatational and its compositional dependence obeys the Vegard's law. Both two- and three-dimensional systems were studied. The Cahn-Hilliard equation was numerically solved using a semi-implicit Fourier-spectral method. It was demonstrated that, with increasing elastic energy contribution, the equilibrium shape of a coherent particle gradually changes from a circle to a square in two dimensions, and from a sphere to a cube in three dimensions, and the composition profile becomes increasingly inhomogeneous within the precipitate with the minimum at the center of the particle, consistent with previous theoretical studies and experimental observations. It was also shown that, with sufficiently large elastic strain energy contribution, a coherent particle may split to four particles from a square, or eight particles from a sphere, during its evolution to equilibrium. For both two and three dimensions, the splitting starts by nucleating the matrix phase at the center of the particle.
Three-Dimensional Simulations of Phase Separation in Model Binary Alloy Systems with Elasticity
Authors: Orlikowski D. , Sagui C. , Somoza A. S. , Roland C. 
Published: April 2011

ABSTRACTWe report on large-scale three-dimensional simulations of phase separation in model binary alloy systems in the presence of elastic fields. The elastic field has several important effects on the morphology of the system: the ordered domains are subject to shape transformations, and spatial ordering. In contrast to two-dimensional system, no significant slowing down in the growth is observed. There is also no evidence of any “reverse coarsening” of the domains.
Stress-Driven Collective Nucleation of Dislocation Loops
Authors: Sun Y. Q. , Hazzledine P. M. , Dimiduki D. M. 
Published: April 2011

ABSTRACTThis paper presents an analysis of the collective nucleation of glide dislocation loops under the bias of a high shear stress. It introduces the concept of an ‘induced’ stress field associated with the planar distribution of glide dislocation loops. It shows that, due to the ‘induced’ field, glide dislocations nucleate in a collective, self-catalytic fashion at critical stresses and temperatures.
Kinetics of Ordering in Cu3Au
Authors: Lang H. , Pfeiler W. 
Published: April 2011

ABSTRACTL12-long-range ordering (LRO) was studied by residual resistometry in Cu3Au. Variations of LRO-parameter were produced by isochronal and isothermal heat treatments for different initial states of order. By comparison of order-order and disorder-order relaxations, the contributions to ordering of atomic jumps within ordered domains and of antiphase boundaries were separated. Analysing isothermal annealings yielded ordering energies of vacancies involved.