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1.	Arwin, Hans, et al. (author) Chirality-induced polarization effects in the cuticle of scarab beetles: 100 years after Michelson 2012 In: Philosophical Magazine. - : Taylor and Francis: STM, Behavioural Science and Public Health Titles / Taylor and Francis. - 1478-6435 .- 1478-6443. ; 92:12, s. 1583-1599 Journal article (peer-reviewed)abstract One hundred years ago Michelson discovered circular polarization in reflection from beetles. Today a novel Mueller-matrix ellipsometry setup allows unprecedented detailed characterization of the beetles polarization properties. A formalism based on elliptical polarization for description of reflection from scarab beetles is here proposed and examples are given on four beetles of different character: Coptomia laevis - a simple dielectric mirror; Cetonia aurata - a left-hand narrow- band elliptical polarizer; Anoplognathus aureus - a broad-band elliptical polarizer; and Chrysina argenteola - a left-hand polarizer for visible light at small angles, whereas for larger angles, red reflected light is right-handed polarized. We confirm the conclusion of previous studies which showed that a detailed quantification of ellipticity and degree of polarization of cuticle reflection can be performed instead of only determining whether reflections are circularly polarized or not. We additionally investigate reflection as a function of incidence angle. This provides much richer information for understanding the behaviour of beetles and for structural analysis.
2.	Bargmann, Swantje, 1980, et al. (author) Modeling of polycrystals with gradient crystal plasticity: A comparison of strategies 2010 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 90:10, s. 1263-1288 Journal article (peer-reviewed)abstract This paper treats the computational modeling of size dependence in microstructure models of metals. Different gradient crystal plasticity strategies are analyzed and compared. For the numerical implementation, a dual-mixed finite element formulation which is suitable for parallelization is suggested. The paper ends with a representative numerical example for polycrystals.
3.	Belonoshko, Anatoly B., et al. (author) A possible mechanism of copper corrosion in anoxic water 2012 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 92:36, s. 4618-4627 Journal article (peer-reviewed)abstract Recent experiments show that solid Cu reacts with anoxic water. The reaction is observed by measuring the hydrogen release. This release is continuous and stable over a period of months. We have since theoretically found that water adsorbs dissociatively at a copper surface. But this adsorption is not enough to explain the amount of hydrogen released in the experiment. This observation calls for the explanation of the removal of the reaction product from the surface to provide a clean Cu surface where the water dissociation takes place. In this paper we investigate, by first-principles calculations, two possible mechanisms for this removal: first the possibility of Cu-O-H nanoparticulate formation, and second the diffusion of the dissociation products into Cu. We show that while the formation of nanoparticulates is energetically unfavorable, the diffusion of OH along grain boundaries can be substantial. The OH being placed in a grain boundary of the Cu sample quickly dissociates and O and H atoms diffuse independently of each other. Such a diffusion is markedly larger than the diffusion in bulk Cu. Thus, grain boundary diffusion is a viable mechanism for providing a clean Cu surface for the dissociation of water at the Cu surface. An order-of-magnitude estimate of the amount of hydrogen released in this case agrees with experiment. But this mechanism is not enough to explain the result of the experiment. We propose the formation of nanocrystals of copper oxide as a second step. A decisive experiment is proposed.
4.	Bjerkén, Christina, et al. (author) Phase ordering kinetics of second-phase formation near an edge dislocation 2014 In: Philosophical Magazine. - : Taylor & Francis. - 1478-6435 .- 1478-6443. ; 94:6, s. 569-593 Journal article (peer-reviewed)abstract The time-dependent Ginzburg-Landau (TDGL) equation for a single component non-conservative structural order parameter is used to study the spatio-temporal evolution of a second phase in the vicinity of an edge dislocation in an elastic crystalline solid. A symmetric Landau potential of sixth-order is employed. Dislocation field and elasticity modify the second-order and fourth-order coefficients of the Landau polynomial, respectively, where the former makes the coefficient singular at the origin. The TDGL equation is solved numerically using a finite volume method, where a wide range of parameter sets is explored. Computations are made for temperatures both above and below the transition temperature of a defect-free crystal Tc0. In both cases, the effects of the elastic properties of the solid and the strength of interaction between the order parameter and the displacement field are examined. If the system is quenched below Tc0, a steady state is first reached on the compressive side of the dislocation. On the tensile side, the growth is held back. The effect of thermal noise term in the TDGL equation is studied. We find that if the dislocation is introduced above Tc0, thermal noise supports the nucleation of the second phase, and a steady state will be attained earlier than if the thermal noise was absent. For a dislocation-free solid, we have compared our numerical computations for a mean-field (spatially averaged) order parameter versus time with the late time growth of the ensemble-averaged order parameter, calculated analytically, and find that both results follow upper asymptotes of sigmoid curves.
5.	Boschker, J. E., et al. (author) In-plane structural order of domain engineered La0.7Sr0.3MnO3 thin films 2013 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 93:13, s. 1549-1562 Journal article (peer-reviewed)abstract We present a detailed structural study of tensile-strained La0.7Sr0.3MnO3 thin films. We use the substrate miscut to control the number of rhombohedral variants in the films and study the in-plane order and structural distortions. Using high-resolution X-ray diffraction, we demonstrate that step-edge induced lattice modulations occur in 4-variant films, whereas periodic twinning is the dominant in-plane order for 2-variant films. We show that the in-plane twinning angle is almost completely relaxed. However, the relaxation of shear strain by the out-of-plane twinning angle and the monoclinic distortion is only partial. Furthermore, the film thickness dependence of the domain width reveals that domain formation is a universal mechanism for shear strain relaxation. Finally, we show that the structural response to the transition from the paramagnetic to the ferromagnetic phase of La0.7Sr0.3MnO3 at 345K is smaller in 4-variant films compared to 2-variant films.
6.	Djurabekova, F., et al. (author) Kinetics versus thermodynamics in materials modeling : The case of the di-vacancy in iron 2010 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 90:19, s. 2585-2595 Journal article (peer-reviewed)abstract Monte Carlo models are widely used for the study of microstructural and microchemical evolution of materials under irradiation. However, they often link explicitly the relevant activation energies to the energy difference between local equilibrium states. We provide a simple example (di-vacancy migration in iron) in which a rigorous activation energy calculation, by means of both empirical interatomic potentials and density functional theory methods, clearly shows that such a link is not granted, revealing a migration mechanism that a thermodynamics-linked activation energy model cannot predict. Such a mechanism is, however, fully consistent with thermodynamics. This example emphasizes the importance of basing Monte Carlo methods on models where the activation energies are rigorously calculated, rather than deduced from widespread heuristic equations.
7.	Hoque, S. Manjura, et al. (author) Detailed study of ultra-soft magnetic properties of Fe74Cu0.8Nb2.7Si15.5B7 2011 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 91:16, s. 2117-2139 Journal article (peer-reviewed)abstract The magnetic properties of nanocrystalline Fe74Cu0.8Nb2.7Si15.5B7 alloy, which were rapidly solidified and then annealed at various temperatures between 475 and 650 degrees C for different holding time, have been studied. Grain size, silicon content and the lattice parameter of alpha-Fe(Si) nanograins at the annealing temperatures were determined. Curie temperature of the amorphous phase was determined from the temperature dependence of permeability. For higher annealing temperatures and times, some Si diffused out of the alpha-Fe(Si) phase and formed an ordered DO3 phase of Fe3Si. This changed the overall magnetostriction and average anisotropy of the matrix, which deteriorated the magnetic softness of the material at higher annealing temperatures. Ultra-soft magnetic properties were achieved by averaging the random anisotropy via exchange interaction. Hysteresis loops for samples in as-cast and annealed conditions have also been studied.
8.	Kádas, Krisztina, et al. (author) Theoretical prediction of the elastic properties of body-centered cubic Fe-Ni-Mg alloys under extreme conditions 2012 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 92:7, s. 888-898 Journal article (peer-reviewed)abstract Using density functional theory formulated within the framework of the exact muffin-tin orbital method, we investigate the elastic properties of the body-centered cubic Fe0.85Ni0.1Mg0.05 alloy in the conditions at the Earth's inner core. We demonstrate that in this system, the chemical stabilization effect of Mg is significantly larger than that of Ni. We show that the elastic properties of Fe(0.85)Ni(0.1)Mg(0.0)5 are in good agreement with those of the Earth's inner core, as given by seismic observations. We find that the excellent mechanical properties of Fe0.85Ni0.1Mg0.05 are primarily due to Mg.
9.	Kotetes, P., et al. (author) Magnetic-field-induced chiral hidden order in URu2Si2 2014 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 94:32-33, s. 3789-3802 Journal article (peer-reviewed)abstract Two of the most striking and yet unresolved manifestations of the hidden order (HO) in [GRAPHICS] are associated, on one hand, with the double-step metamagnetic transitions and, on the other, with the giant anomalous Nernst signal. Both are observed when a magnetic field is applied along the [GRAPHICS] -axis. Here, we provide for the first time a unified understanding of these puzzling phenomena and the related field-temperature ( [GRAPHICS] ) phase diagram. We demonstrate that the HO phase at finite fields can be explained with a chiral [GRAPHICS] spin density wave, assuming that the zero-field HO contains only the time-reversal symmetry preserving [GRAPHICS] component. We argue that the presence of the field-induced chiral HO can be reflected in a distinctive non-linear [GRAPHICS] dependence of the Kerr angle, when a Kerr experiment is conducted for finite fields. This fingerprint can be conclusive for the possible emergence of chirality in the HO.
10.	Lasich, Matthew, et al. (author) On the application of binary correction factors in lattice distortion calculations for methane clathrate hydrate 2014 In: Philosophical Magazine. - : Taylor & Francis. - 1460-6992 .- 1478-6435 .- 1478-6443. ; 94:9, s. 974-990 Journal article (peer-reviewed)abstract The lattice distortion theory of Zele and co-workers is an attractive method for amending calculated phase equilibria of clathrate hydrates, since only two molecular computations are required. The perturbation energy between the empty and loaded clathrate hydrate lattice is the quantity of interest. The effect of binary correction factors applied to the Lorentz and Berthelot com- bining rules for the intermolecular interaction between gas and water particles is investigated. There are clear trends for the perturbation energy and lattice constant in terms of the binary correction factors, although there is signi fi cant sensitivity to the force fi eld parameterization of the gas species.
11.	Lundow, Per Håkan, et al. (author) On the p, q-binomial distribution and the Ising model 2010 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 90:24, s. 3313-3353 Journal article (peer-reviewed)abstract We employ p, q-binomial coefficients, a generalisation of the binomial coefficients, to describe the magnetisation distributions of the Ising model. For the complete graph this distribution corresponds exactly to the limit case p = q. We apply our investigation to the simple d-dimensional lattices for d = 1, 2, 3, 4, 5 and fit p, q-binomial distributions to our data, some of which are exact but most are sampled. For d = 1 and d = 5, the magnetisation distributions are remarkably well-fitted by p,q-binomial distributions. For d = 4 we are only slightly less successful, while for d = 2, 3 we see some deviations (with exceptions!) between the p, q-binomial and the Ising distribution. However, at certain temperatures near Tc the statistical moments of the fitted distribution agree with the moments of the sampled data within the precision of sampling. We begin the paper by giving results of the behaviour of the p, q-distribution and its moment growth exponents given a certain parameterisation of p, q. Since the moment exponents are known for the Ising model (or at least approximately for d = 3) we can predict how p, q should behave and compare this to our measured p, q. The results speak in favour of the p, q-binomial distribution's correctness regarding its general behaviour in comparison to the Ising model. The full extent to which they correctly model the Ising distribution, however, is not settled.
12.	Lundow, Per Håkan, et al. (author) The p,q-binomial distribution applied to the 5d Ising model 2013 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 93:14, s. 1755-1770 Journal article (peer-reviewed)abstract The leading order form of the magnetization distribution is well-known for the 5d Ising model close to . Its corrections-to-scaling are not known though. Since we have earlier established that this distribution is extremely well-fitted by a -binomial distribution, we report considerably longer series expansions for its moments in terms of three parameters, providing new details on the scaling behaviour of the Ising distribution and its moments near . As applications, we give for example the scaling formulas for the ratios , and the full distribution at .
13.	Massih, Ali (author) Second-phase nucleation on an edge dislocation 2011 In: Philosophical Magazine. - : Taylor & Francis. - 1478-6435 .- 1478-6443. ; 91, s. 3961-3980 Journal article (peer-reviewed)abstract A model for nucleation of second phase at or around dislocation in a crystalline solid is considered. The model employs the Ginzburg-Landau theory of phase transition comprising the sextic term in order parameter in the Landau free energy. The ground state solution of the linearized time-independent Ginzburg-Landau equation has been derived, through which the spatial variation of the order parameter has been delineated. Moreover, a generic phase diagram indicating a tricritical behavior near and away from the dislocation is depicted. The relation between the classical nucleation theory and the Ginzburg-Landau approach has been discussed, for which the critical formation energy of nucleus is related to the maximal of the Landau potential energy. A numerical example illustrating the application of the model to the case of nucleation of hydrides in zirconium alloys is provided.
14.	Mukhopadhyay, N K, et al. (author) Strain-induced structural transformation of single-phase Al–Cu–Fe icosahedral quasicrystal during mechanical milling 2011 In: Philosophical Magazine. - : Taylor & Francis. - 1478-6435 .- 1478-6443. ; 91:19-21, s. 2482-2490 Journal article (peer-reviewed)
15.	Mydosh, J. A., et al. (author) Hidden order behaviour in URu2Si2 (A critical review of the status of hidden order in 2014) 2014 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 94:32-33, s. 3642-3662 Journal article (peer-reviewed)abstract Throughout the past three decades, the hidden order (HO) problem in URu2Si2 has remained a 'hot topic' in the physics of strongly correlated electron systems with well over 600 publications related to this subject. Presently in 2014, there has been significant progress in combining various experimental results embedded within electronic structure calculations using density functional theory (DFT) to give a consistent description of the itinerant behaviour of the HO transition and its low temperature state. Here, we review six different experiments: ARPES, quantum oscillations, neutron scattering, RXD, optical spectroscopy and STM/STS. We then establish the consistencies among these experiments when viewed through the Fermi-surface nesting, folding and gapping framework as predicted by DFT. We also discuss a group of other experiments (torque, cyclotron resonance, NMR and XRD) that are more controversial and are presently in a 'transition' state regarding their interpretation as rotational symmetry breaking and dotriacontapole formation. There are also a series of recent 'exotic' experiments (Raman scattering, polar Kerr effect and ultrasonics) that require verification, yet they offer new insights into the HO symmetry breaking and order parameter. We conclude with some constraining comments on the microscopic models that rely on localized 5f-U states and strong Ising anisotropy for explaining the HO transition, and with an examination of different models in the light of recent experiments.
16.	Punkkinen, M.P.J., et al. (author) Surface properties of 3d transition metals 2011 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 91:27, s. 3627-3640 Journal article (peer-reviewed)abstract Using the projector augmented wave method within density functional theory, we present a systematic study of the layer relaxation, surface energy and surface stress of 3d transition metals. Comparing the calculated trends for the surface energy and stress with those obtained for 4d and 5d metals we find that magnetism has a significant effect on the surface properties. Enhanced surface magnetic moments decrease the size of the surface relaxation, lower the surface energy and surface stress, leading to compressive stress in Cr and Mn.
17.	Rahaman, Moshiour, et al. (author) Temperature dependence of stacking-fault and anti-phase boundary energies in Al3Sc from ab initio calculations 2013 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 93:25, s. 3423-3441 Journal article (peer-reviewed)abstract Temperature dependence of intrinsic stacking-fault energies (SFE) and anti-phase boundary energies (APBE) of AlSc is investigated in first-principles calculations using the axial Ising model and supercell approach. The temperature effect has been taken into consideration by including the one-electron thermal excitations in the electronic structure calculations, and vibrational free energy in the harmonic approximation as well as by using temperature dependent lattice constant. The latter has been determined within the Debye-Gruneisen model, which reproduces well the experimental data. The APBE and SFE are found to be reduced by about 10% in the temperature interval from 0 to 1000 K. It is shown that the inclusion of the free energy of lattice vibrations in the harmonic approximation increases the SFE further by about 4%. We also find a substantial contribution from local lattice relaxations in the case of APBE for the (111) plane and SFE leading to their reduction by about 30%.
18.	Ruban, Andrei V., et al. (author) First-principles study of point defects in Ni3Al 2014 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 94:1, s. 20-34 Journal article (peer-reviewed)abstract The energetics and structural properties of native, substitutional and interstitial defects in Ni3Al have been investigated by first-principles methods. In particular, we have determined the formation energies of composition conserving defects and established that the so-called penta defect, which consists of four vacancies on Ni sublattice and Ni antisite on the Al sublattice, is the main source of vacancies in Ni3Al. We show that this is due to the strong Ni-site preference of vacancies in Ni3Al. We have also calculated the site substitution behaviour of Cu, Pd, Pt, Si, Ti, Cr, V, Nb, Ta and Mo and their effect on the concentration expansion coefficient. We show the latter information can used for an indirect estimate of the site substitution behaviour of the alloying elements. The solution energy of carbon and its effect on the lattice constant of Ni3Al have been obtained in the dilute limit in the first-principles calculations. We have also determined the chemical and strain-induced carbon-carbon interactions in the interstitial positions of Ni3Al. These interactions have been subsequently used in the statistical thermodynamic simulations of carbon ordering in Ni3Al.
19.	Ruban, Andrei V. (author) Single-site mean-field approach to thermal defects in binary ordered alloys 2014 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 94:11, s. 1192-1201 Journal article (peer-reviewed)abstract A single-site mean-field approach for the concentration of thermal defects in a binary intermetallic AB compound is proposed, which is a modification of previously existing Wagner-Schottky-type models. A numerical investigation of the model is done for the case of thermal defects in NiAl.
20.	Shen, Zhijian, et al. (author) Rapid synthesis and densification of single-phase Al-Cu-Fe quasicrystals by spark plasma sintering or microwave heating 2010 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 91:19-20, s. 1478-6443 Journal article (peer-reviewed)abstract Quasicrystalline (QC) phases are often stable only within narrow composition domains. For this reason, the synthesis of larger amounts of single-phase quasicrystalline powders is difficult. Powder metallurgical approaches, based on mechanical milling followed by conventional heating, have been explored in the recent past. The manufacturing process for single-phase quasicrystals - either in the form of powders or as bulk parts - can be accelerated by orders of magnitude using rapid heating methods that involve pulsed electric currents and/or high-frequency electromagnetic fields. Prior knowledge of the phase transformation sequence and transformation kinetics, as revealed by in situ time-resolved synchrotron radiation experiments, is crucial in obtaining single-phase quasicrystals. We report on the simultaneous synthesis and densification of bulk single-phase Al-Cu-Fe QCs by spark plasma sintering (SPS) within minutes and on the ultrafast synthesis of single-phase Al-Cu-Fe quasicrystalline powders by microwave heating within seconds. The effect of electric current application in the rapid processing of pre-alloyed powders is discussed in relation to the faster diffusion and enhanced phase transformation kinetics.
21.	Talreja, Ramesh (author) On multi-scale approaches to composites and heterogeneous solids with damage 2010 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 90:31-32, s. 4333-4348 Journal article (peer-reviewed)abstract The explosive increase in computational power and the paradigm of computer-based engineering practice have prompted analyses that claim to carry knowledge of material physics at small scales to the performance observed at the structural level. This hierarchical multi-scale approach has logical appeal and some mathematical formulation to support it for heterogeneous solids. However, when such solids suffer damage in the form of multiple cracks, the length scale hierarchy is no longer fixed or simple. Connecting multiple scales is then a challenge that needs addressing for given material systems, such as composite laminates, accounting for the pertinent damage. This paper describes damage in fiber-reinforced composites, illustrating the characteristic length scales of damage and their relationship with the fixed scales of heterogeneities. Hierarchical versus top-down approaches are discussed and a case is made for the so-called synergistic approach that combines continuum damage mechanics and micro-damage mechanics
22.	Östlund, Fredrik, et al. (author) Ductile-brittle transition in micropillar compression of GaAs at room temperature 2011 In: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 91:7-9, s. 1190-1199 Journal article (peer-reviewed)abstract Experiments have been carried out on how compressive failure of < 100 > axis GaAs micropillars at room temperature is influenced by their diameter. Slip was observed in all micropillars, often on intersecting slip planes. Cracks could nucleate at these intersections and then grow axially in the sample, with bursts of crack growth. However, GaAs micropillars with diameters less than approximately 1 mu m did not split, nor was splitting observed where slip occurred on only one plane. The conditions under which such splitting can occur have been estimated by modifying an existing analysis. This predicts a ductile-brittle transition at a micropillar diameter of approximately 1 mu m, consistent with experimental observations.

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