WorldWideScience

Sample records for stripe domain walls

  1. Nanoscale control of stripe-ordered magnetic domain walls by vertical spin transfer torque in La0.67Sr0.33MnO3 film

    Science.gov (United States)

    Wang, Jing; Wu, Shizhe; Ma, Ji; Xie, Lishan; Wang, Chuanshou; Malik, Iftikhar Ahmed; Zhang, Yuelin; Xia, Ke; Nan, Ce-Wen; Zhang, Jinxing

    2018-02-01

    Stripe-ordered domains with perpendicular magnetic anisotropy have been intensively investigated due to their potential applications in high-density magnetic data-storage devices. However, the conventional control methods (e.g., epitaxial strain, local heating, magnetic field, and magnetoelectric effect) of the stripe-ordered domain walls either cannot meet the demands for miniaturization and low power consumption of spintronic devices or require high strength of the electric field due to the small value of the magnetoelectric effect at room temperature. Here, a domain-wall resistive effect of 0.1% was clarified in La0.67Sr0.33MnO3 thin films between the configurations of current in the plane and perpendicular to the plane of walls. Furthermore, a reversible nanoscale control of the domain-wall re-orientation by vertical spin transfer torque across the probe/film interface was achieved, where a probe voltage of 0.1 V was applied on a manganite-based capacitor. We also demonstrated that the stripe-ordered magnetic domain-wall re-orientation strongly depends on the AC frequency of the scanning probe voltage which was applied on the capacitor.

  2. Anisotropy of domain wall resistance

    Science.gov (United States)

    Viret; Samson; Warin; Marty; Ott; Sondergard; Klein; Fermon

    2000-10-30

    The resistive effect of domain walls in FePd films with perpendicular anisotropy was studied experimentally as a function of field and temperature. The films were grown directly on MgO substrates, which induces an unusual virgin magnetic configuration composed of 60 nm wide parallel stripe domains. This allowed us to carry out the first measurements of the anisotropy of domain wall resistivity in the two configurations of current perpendicular and parallel to the walls. At 18 K, we find 8.2% and 1.3% for the domain wall magnetoresistance normalized to the wall width (8 nm) in these two respective configurations. These values are consistent with the predictions of Levy and Zhang.

  3. Domain wall diffusion and domain wall softening

    International Nuclear Information System (INIS)

    Lee, W T; Salje, E K H; Bismayer, U

    2003-01-01

    A number of experimental and computational studies of materials have shown that transport rates in domain walls may significantly differ from those in the bulk. One possible explanation for enhanced transport in a domain wall is that the domain wall is elastically soft with respect to the bulk. We investigate the softening of a ferroelastic domain wall in a simple, generic model. We calculate saddle point energies of solute atoms in the bulk and domain wall, using a geometry such that variation in the saddle point energy cannot be attributed to the structural differences of the bulk and the wall, but must instead be attributed to softening of the wall. Our results show a reduction of the saddle point energy in the wall, thus indicating that, in this model at least, domain walls are elastically soft compared with the bulk. A simple analysis based on an Einstein model allows us to explain the observed softening of the wall

  4. Crystal shapes on striped surface domains

    International Nuclear Information System (INIS)

    Valencia, Antoni

    2004-01-01

    The equilibrium shapes of a simple cubic crystal in contact with a planar chemically patterned substrate are studied theoretically using an effective interface model. The substrate is primarily made of lyophobic material and is patterned with a lyophilic (easily wettable) stripe domain. Three regimes can be distinguished for the equilibrium shapes of the crystal. The transitions between these regimes as the volume of the crystal is changed are continuous or discontinuous depending on the strength of the couplings between the crystal and the lyophilic and lyophobic surface domains. If the crystal grows through a series of states close to equilibrium, the discontinuous transitions correspond to growth instabilities. These transitions are compared with similar results that have been obtained for a volume of liquid wetting a lyophilic stripe domain

  5. Ferromagnetic stripe domains in ultrathin films

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, B. [Department of Secondary Science and Mathematics Education, University of Mersin, Yenisehir Campus, 33169 Mersin (Turkey)]. E-mail: bengukaplan@yahoo.com

    2005-03-01

    Using simple magnetostatic considerations, we discuss the domain structure and the domain-wall width, {omega}, in ultrathin magnetic films (of a few monolayer thickness) and in an atomic monolayer. The demagnetizing energy is calculated in a continuum theory which is valid provided that the domains are large compared with the lattice spacing. The calculated domain-wall width, {omega}, and the surface anisotropy constant, K{sub s}, are compared with the experimental data for thin epitaxial Co/Au (111) films and a good coincidence is obtained between both results.

  6. Supersymmetric domain walls

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Kleinschmidt, Axel; Riccioni, Fabio

    2012-01-01

    We classify the half-supersymmetric "domain walls," i.e., branes of codimension one, in toroidally compactified IIA/IIB string theory and show to which gauged supergravity theory each of these domain walls belong. We use as input the requirement of supersymmetric Wess-Zumino terms, the properties of

  7. Stripe domains and magnetoresistance in thermally deposited nickel films

    International Nuclear Information System (INIS)

    Sparks, P.D.; Stern, N.P.; Snowden, D.S.; Kappus, B.A.; Checkelsky, J.G.; Harberger, S.S.; Fusello, A.M.; Eckert, J.C.

    2004-01-01

    We report a study of the domain structure and magnetoresistance of thermally deposited nickel films. For films thicker than 17 nm, we observe striped domains with period varying with film thickness as a power law with exponent 0.21±0.02 up to 120 nm thickness. There is a negative magnetoresistance for fields out of the plane

  8. Structural domain walls in polar hexagonal manganites

    Science.gov (United States)

    Kumagai, Yu

    2014-03-01

    The domain structure in the multiferroic hexagonal manganites is currently intensely investigated, motivated by the observation of intriguing sixfold topological defects at their meeting points [Choi, T. et al,. Nature Mater. 9, 253 (2010).] and nanoscale electrical conductivity at the domain walls [Wu, W. et al., Phys. Rev. Lett. 108, 077203 (2012).; Meier, D. et al., Nature Mater. 11, 284 (2012).], as well as reports of coupling between ferroelectricity, magnetism and structural antiphase domains [Geng, Y. et al., Nano Lett. 12, 6055 (2012).]. The detailed structure of the domain walls, as well as the origin of such couplings, however, was previously not fully understood. In the present study, we have used first-principles density functional theory to calculate the structure and properties of the low-energy structural domain walls in the hexagonal manganites [Kumagai, Y. and Spaldin, N. A., Nature Commun. 4, 1540 (2013).]. We find that the lowest energy domain walls are atomically sharp, with {210}orientation, explaining the orientation of recently observed stripe domains and suggesting their topological protection [Chae, S. C. et al., Phys. Rev. Lett. 108, 167603 (2012).]. We also explain why ferroelectric domain walls are always simultaneously antiphase walls, propose a mechanism for ferroelectric switching through domain-wall motion, and suggest an atomistic structure for the cores of the sixfold topological defects. This work was supported by ETH Zurich, the European Research Council FP7 Advanced Grants program me (grant number 291151), the JSPS Postdoctoral Fellowships for Research Abroad, and the MEXT Elements Strategy Initiative to Form Core Research Center TIES.

  9. Domain Walls with Strings Attached

    Energy Technology Data Exchange (ETDEWEB)

    Shmakova, Marina

    2001-08-20

    We have constructed a bulk and brane action of IIA theory which describes a pair of BPS domain walls on S{sub 1}/Z{sub 2}, with strings attached. The walls are given by two orientifold O8-planes with coincident D8-branes and F1-D0-strings are stretched between the walls. This static configuration satisfies all matching conditions for the string and domain wall sources and has 1/4 of unbroken supersymmetry.

  10. Individual domain wall resistance in submicron ferromagnetic structures.

    Science.gov (United States)

    Danneau, R; Warin, P; Attané, J P; Petej, I; Beigné, C; Fermon, C; Klein, O; Marty, A; Ott, F; Samson, Y; Viret, M

    2002-04-15

    The resistance generated by individual domain walls is measured in a FePd nanostructure. Combining transport and magnetic imaging measurements, the intrinsic domain wall resistance is quantified. It is found positive and of a magnitude consistent with that predicted by models based on spin scattering effects within the walls. This magnetoresistance at a nanometer scale allows a direct counting of the number of walls inside the nanostructure. The effect is then used to measure changes in the magnetic configuration of submicron stripes under application of a magnetic field.

  11. Eight-Vertex Model of Two-Dimensional Domain Walls

    Science.gov (United States)

    Rys, Franz S.

    1983-09-01

    A statistical model of interacting linear domain walls (occurring, e.g., in monolayer adsorbates) is solved on the square lattice with use of exact and numerical results of an equivalent eight-vertex model. For attractive walls a commensurate and an incommensurate phase are separated by a first-order line for stiff walls and by a fluid phase for flexible walls. The phase boundaries with the fluid phase are Ising-like. For repulsive stiff walls an intermediate striped phase with a nonuniversal boundary occurs which vanishes for higher flexibilities. Moreover, disorder lines are located.

  12. Persistent conductive footprints of 109o domain walls in bismuth ferrite films

    NARCIS (Netherlands)

    Stolichnov, I.; Iwanowska, M.; Colla, E.; Ziegler, B.; Gaponenko, I.; Paruch, P.; Huijben, Mark; Rijnders, Augustinus J.H.M.; Setter, N.

    2014-01-01

    Using conductive and piezoforce microscopy, we reveal a complex picture of electronic transport at weakly conductive 109° domain walls in bismuth ferrite films. Even once initial ferroelectric stripe domains are changed/erased, persistent conductive paths signal the original domain wall position.

  13. Flexoelectricity in nematic domain walls.

    Science.gov (United States)

    Elston, Steve J

    2008-07-01

    Flexoelectric effects are studied in the domain walls of a nematic liquid crystal device showing the Freedericksz transition. Walls parallel to the alignment direction have a strong twist distortion and an electro-optic effect dominated by e1-e3 is seen. Walls perpendicular to the alignment direction have a strong splay-bend distortion and an electro-optic effect dominated by e1+e3 is seen. This allows the study of both flexoelectric coefficient combinations in a single device.

  14. Magnetic stripes and holes: Complex domain patterns in perforated films with weak perpendicular anisotropy

    Directory of Open Access Journals (Sweden)

    F. Valdés-Bango

    2017-05-01

    Full Text Available Hexagonal antidot arrays have been patterned on weak perpendicular magnetic anisotropy NdCo films by e-beam lithography and lift off. Domain structure has been characterized by Magnetic Force Microscopy at remanence. On a local length scale, of the order of stripe pattern period, domain configuration is controlled by edge effects within the stripe pattern: stripe domains meet the hole boundary at either perpendicular or parallel orientation. On a longer length scale, in-plane magnetostatic effects dominate the system: clear superdomains are observed in the patterned film with average in-plane magnetization along the easy directions of the antidot array, correlated over several antidot array cells.

  15. Magnetic stripes and holes: Complex domain patterns in perforated films with weak perpendicular anisotropy

    Science.gov (United States)

    Valdés-Bango, F.; Vélez, M.; Alvarez-Prado, L. M.; Alameda, J. M.; Martín, J. I.

    2017-05-01

    Hexagonal antidot arrays have been patterned on weak perpendicular magnetic anisotropy NdCo films by e-beam lithography and lift off. Domain structure has been characterized by Magnetic Force Microscopy at remanence. On a local length scale, of the order of stripe pattern period, domain configuration is controlled by edge effects within the stripe pattern: stripe domains meet the hole boundary at either perpendicular or parallel orientation. On a longer length scale, in-plane magnetostatic effects dominate the system: clear superdomains are observed in the patterned film with average in-plane magnetization along the easy directions of the antidot array, correlated over several antidot array cells.

  16. Static domain wall in braneworld gravity

    Energy Technology Data Exchange (ETDEWEB)

    Abdalla, M.C.B.; Carlesso, P.F. [UNESP, Universidade Estadual Paulista, Instituto de Fisica Teiorica, Rua Dr. Bento Teobaldo Ferraz 271, Bloco II, Barra-Funda, Caixa Postal 70532-2, Sao Paulo, SP (Brazil); Hoff da Silva, J.M. [UNESP, Universidade Estadual Paulista, Departamento de Fisica e Quimica, Guaratingueta, SP (Brazil)

    2014-01-15

    In this paper we consider a static domain wall inside a 3-brane. Different from the standard achievement obtained in General Relativity, the analysis performed here gives a consistency condition for the existence of static domain walls in a braneworld gravitational scenario. Also the behavior of the domain wall's gravitational field in the newtonian limit is shown. (orig.)

  17. Skyrmions from Instantons inside Domain Walls

    International Nuclear Information System (INIS)

    Eto, Minoru; Nitta, Muneto; Ohashi, Keisuke; Tong, David

    2005-01-01

    Some years ago, Atiyah and Manton described a method to construct approximate Skyrmion solutions from Yang-Mills instantons. Here we present a dynamical realization of this construction using domain walls in a five-dimensional gauge theory. The non-Abelian gauge symmetry is broken in each vacuum but restored in the core of the domain wall, allowing instantons to nestle inside the wall. We show that the world volume dynamics of the wall is given by the Skyrme model, including the four-derivative term, and the instantons appear as domain wall Skyrmions

  18. Planar domain walls in black hole spacetimes

    Science.gov (United States)

    Ficek, Filip; Mach, Patryk

    2018-02-01

    We investigate the behavior of low-mass, planar domain walls in the so-called ϕ4 model of the scalar field on the Schwarzschild and Kerr backgrounds. We focus on a transit of a domain wall through a black hole and solve numerically the equations of motion for a range of parameters of the domain wall and the black hole. We observe a behavior resembling an occurrence of ringing modes. Perturbations of domain walls vanish during latter evolution, suggesting their stability against a passage through the black hole. The results obtained for Kerr and Reissner-Nordström black holes are also compared.

  19. Superfast domain walls in KTP single crystals

    Science.gov (United States)

    Shur, V. Ya.; Esin, A. A.; Alam, M. A.; Akhmatkhanov, A. R.

    2017-10-01

    Potassium titanyl phosphate KTiOPO4 (KTP) crystals with periodical ferroelectric domain structures are one of the most promising materials for nonlinear optics, in which the main types of nonlinear optical interactions have been demonstrated. Despite the crucial importance of the in situ visualization of domain structure kinetics for creation of high quality periodical domain gratings, there are only a few works concerning KTP. We present the results of in situ visualization of domain kinetics in KTP with the time resolution down to 12.5 μs and simultaneous recording of the switching current data. The wide range of wall velocities with two orders of magnitude difference was observed for switching in a uniform electric field. The kinetic maps allowed analyzing the spatial distribution of wall motion velocities and classifying the walls by velocity ranges. The distinguished slow, fast, and superfast types of domain walls differed by their orientation. It was shown that the fast and slow domain walls provided the smooth input to the switching current, whereas the short-lived superfast walls resulted in short current peaks. The mobility and the threshold fields for all types of domain walls were estimated. The revealed increase in the wall velocity with deviation from low-index crystallographic planes for slow and fast walls was considered in terms of determined step generation and anisotropic kink motion. The obtained results are important for further development of domain engineering in KTP required for creation of high power, reliable, and effective coherent light sources.

  20. Theory of topological edges and domain walls

    NARCIS (Netherlands)

    Bais, F.A.; Slingerland, J.K.; Haaker, S.M.

    2009-01-01

    We investigate domain walls between topologically ordered phases in two spatial dimensions. We present a method which allows for the determination of the superselection sectors of excitations of such walls and which leads to a unified description of the kinematics of a wall and the two phases to

  1. Identification of pseudomurein cell wall binding domains.

    Science.gov (United States)

    Steenbakkers, Peter J M; Geerts, Wim J; Ayman-Oz, Nilgün A; Keltjens, Jan T

    2006-12-01

    Methanothermobacter thermautotrophicus is a methanogenic Gram-positive microorganism with a cell wall consisting of pseudomurein. Currently, no information is available on extracellular pseudomurein biology and so far only two prophage pseudomurein autolysins, PeiW and PeiP, have been reported. In this paper we show that PeiW and PeiP contain two different N-terminal pseudomurein cell wall binding domains. This finding was used to identify a novel domain, PB007923, on the M. thermautotrophicus genome present in 10 predicted open reading frames. Three homologues were identified in the Methanosphaera stadtmanae genome. Binding studies of fusion constructs of three separate PB007923 domains to green fluorescent protein revealed that it also constituted a cell wall binding domain. Both prophage domains and the PB007923 domain bound to the cell walls of Methanothermobacter species and fluorescence microscopy showed a preference for the septal region. Domain specificities were revealed by binding studies with other pseudomurein-containing archaea. Localized binding was observed for M. stadtmanae and Methanobrevibacter species, while others stained evenly. The identification of the first pseudomurein cell wall binding domains reveals the dynamics of the pseudomurein cell wall and provides marker proteins to study the extracellular pseudomurein biology of M. thermautotrophicus and of other pseudomurein-containing archaea.

  2. Domain walls and spacetime-filling branes

    NARCIS (Netherlands)

    Bergshoeff, E; Wess, J; Ivanov, EA

    1999-01-01

    We discuss branes with one transversal direction (domain walls) and no transversal direction (spacetime-filling branes). In particular, we briefly discuss a relationship between spacetime-filling branes and superstring theories with sixteen supercharges.

  3. Booted domain wall and charged Kaigorodov space

    International Nuclear Information System (INIS)

    Cai Ronggen

    2003-01-01

    The Kaigorodov space is a homogeneous Einstein space and it describes a pp-wave propagating in anti-de Sitter space. It is conjectured in the literature that M-theory or string theory on the Kaigorodov space times a compact manifold is dual to a conformal field theory in an infinitely-boosted frame with constant momentum density. In this Letter we present a charged generalization of the Kaigorodov space by boosting a non-extremal charged domain wall to the ultrarelativity limit where the boost velocity approaches the speed of light. The finite boost of the domain wall solution gives the charged generalization of the Carter-Novotny-Horsky metric. We study the thermodynamics associated with the charged Carter-Novotny-Horsky space and discuss its relation to that of the static black domain walls and its implications in the domain wall/QFT (quantum field theory) correspondence

  4. Stable charged antiparallel domain walls in hyperferroelectrics

    Science.gov (United States)

    Liu, S.; Cohen, R. E.

    2017-06-01

    Charge-neutral 180° domain walls that separate domains of antiparallel polarization directions are common structural topological defects in ferroelectrics. In normal ferroelectrics, charged 180° domain walls running perpendicular to the polarization directions are highly energetically unfavorable because of the depolarization field and are difficult to stabilize. We explore both neutral and charged 180° domain walls in hyperferroelectrics, a class of proper ferroelectrics with persistent polarization in the presence of a depolarization field, using density functional theory. We obtain zero temperature equilibrium structures of head-to-head and tail-to-tail walls in recently discovered ABC-type hexagonal hyperferroelectrics. Charged domain walls can also be stabilized in canonical ferroelectrics represented by LiNbO3 without any dopants, defects or mechanical clamping. First-principles electronic structure calculations show that charged domain walls can reduce and even close the band gap of host materials and support quasi-two-dimensional electron(hole) gas with enhanced electrical conductivity.

  5. On thick domain walls in general relativity

    Science.gov (United States)

    Goetz, Guenter; Noetzold, Dirk

    1989-01-01

    Planar scalar field configurations in general relativity differ considerably from those in flat space. It is shown that static domain walls of finite thickness in curved space-time do not possess a reflection symmetry. At infinity, the space-time tends to the Taub vacuum on one side of the wall and to the Minkowski vacuum (Rindler space-time) on the other. Massive test particles are always accelerated towards the Minkowski side, i.e., domain walls are attractive on the Taub side, but repulsive on the Minkowski side (Taub-vacuum cleaner). It is also proved that the pressure in all directions is always negative. Finally, a brief comment is made concerning the possibility of infinite, i.e., bigger than horizon size, domain walls in our universe. All of the results are independent of the form of the potential V(phi) greater than or equal to 0 of the scalar field phi.

  6. Magnetic stripe domains of [Pt/Co/Cu]10 multilayer near spin reorientation transition

    Directory of Open Access Journals (Sweden)

    L. Sun

    2016-05-01

    Full Text Available The dependence of magnetic anisotropy, magnetic domain patterns and magnetization reversal processes in [Pt/Co(tCo/Cu]10 film stack epitaxied on Cu (111 substrate have been studied as a function of the Co layer thickness tCo, by magneto-optic polar Kerr magnetometry and microscopy. We find the film undergoes spin reorientation transition from out-of-plane to in-plane as tCo increases. The SRT thickness is verified by Rotating-field Magneto-Optic Kerr effect method. The film exhibits the stripe domain structures at remanence with the width decreasing while tCo approaches SRT. As demonstrated by the first order reversal curve measurement, the magnetization reversal process encompasses irreversible domain nucleation, domain annihilation at large field and reversible domain switching near remanence.

  7. Anomalous feedback and negative domain wall resistance

    International Nuclear Information System (INIS)

    Cheng, Ran; Xiao, Di; Zhu, Jian-Gang

    2016-01-01

    Magnetic induction can be regarded as a negative feedback effect, where the motive-force opposes the change of magnetic flux that generates the motive-force. In artificial electromagnetics emerging from spintronics, however, this is not necessarily the case. By studying the current-induced domain wall dynamics in a cylindrical nanowire, we show that the spin motive-force exerting on electrons can either oppose or support the applied current that drives the domain wall. The switching into the anomalous feedback regime occurs when the strength of the dissipative torque β is about twice the value of the Gilbert damping constant α . The anomalous feedback manifests as a negative domain wall resistance, which has an analogy with the water turbine. (paper)

  8. Oscillatory domain wall velocity of current-induced domain wall motion

    International Nuclear Information System (INIS)

    Kim, W.J.; Seo, S.M.; Lee, T.D.; Lee, K.J.

    2007-01-01

    We studied the effect of Oersted field (H Oe ) on current-induced domain wall motion (CIDWM) in magnetic nanowires. We found that H Oe generates spin waves. Because of interaction between domain wall (DW) and spin wave, time-dependent wall velocity is oscillatory at the early stage of wall motion. The period of the oscillatory DW motion is in antiphase with the period of out-of-plane (OOP) magnetization oscillation inside the DW. The oscillatory wall velocity is suppressed as the thickness of nanowire decreases because of strong demagnetization field

  9. Domain walls in single-chain magnets

    Science.gov (United States)

    Pianet, Vivien; Urdampilleta, Matias; Colin, Thierry; Clérac, Rodolphe; Coulon, Claude

    2017-12-01

    The topology and creation energy of domain walls in different magnetic chains (called Single-Chain Magnets or SCMs) are discussed. As these domain walls, that can be seen as "defects", are known to control both static and dynamic properties of these one-dimensional systems, their study and understanding are necessary first steps before a deeper discussion of the SCM properties at finite temperature. The starting point of the paper is the simple regular ferromagnetic chain for which the characteristics of the domain walls are well known. Then two cases will be discussed (i) the "mixed chains" in which isotropic and anisotropic classical spins alternate, and (ii) the so-called "canted chains" where two different easy axis directions are present. In particular, we show that "strictly narrow" domain walls no longer exist in these more complex cases, while a cascade of phase transitions is found for canted chains as the canting angle approaches 45∘. The consequence for thermodynamic properties is briefly discussed in the last part of the paper.

  10. Compactified webs and domain wall partition functions

    Energy Technology Data Exchange (ETDEWEB)

    Shabbir, Khurram [Government College University, Department of Mathematics, Lahore (Pakistan)

    2017-04-15

    In this paper we use the topological vertex formalism to calculate a generalization of the ''domain wall'' partition function of M-strings. This generalization allows calculation of partition function of certain compactified webs using a simple gluing algorithm similar to M-strings case. (orig.)

  11. Domain wall partition functions and KP

    International Nuclear Information System (INIS)

    Foda, O; Wheeler, M; Zuparic, M

    2009-01-01

    We observe that the partition function of the six-vertex model on a finite square lattice with domain wall boundary conditions is (a restriction of) a KP τ function and express it as an expectation value of charged free fermions (up to an overall normalization)

  12. Leptogenesis with left-right domain walls

    Indian Academy of Sciences (India)

    the scale of left-right symmetry breaking. Keywords. Leptogenesis; baryogenesis; domain walls; left-right symmetry. PACS Nos 12.10.Dm; 98.80.Cq; 98.80.Ft. Explaining the observed baryon asymmetry of the Universe within the framework of gauge theories and the standard Big Bang cosmology remains an open problem.

  13. Fast domain wall dynamics in amorphous and nanocrystalline magnetic microwires

    Energy Technology Data Exchange (ETDEWEB)

    Varga, R., E-mail: rvarga@upjs.sk [Institute of Physics, Faculty of Science, UPJS, Park Angelinum 9, 041 54, Kosice (Slovakia); Klein, P.; Richter, K. [Institute of Physics, Faculty of Science, UPJS, Park Angelinum 9, 041 54, Kosice (Slovakia); Zhukov, A. [Dept. Fisica de Materiales, Fac. Quimica, UPV/EHU, San Sebastian (Spain); Vazquez, M. [Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Ines de la Cruz 3, 28049 Cantoblanco, Madrid (Spain)

    2012-10-15

    We have studied the effect of thermal treatment on the domain wall dynamics of FeSiB and FeCoMoB microwires. It was shown that annealing in transversal magnetic field increases the domain wall mobility as well as the domain wall velocity. Annealing under the tensile stress hinders the appearance of the monodomain structure but application of tensile stress leads to the magnetic bistability having the domain wall mobility twice higher that in as-cast state. Further increase of the tensile stress reduces the domain wall mobility but the domain wall velocity increases as a result of the decrease of critical propagation field. Annealing of the FeCoMoB microwire by Joule heating leads to introduction of the circular anisotropy that favors the vortex domain wall. Such treatment increases the domain wall mobility as well as the maximum domain wall velocity.

  14. Novel domain wall dynamics in synthetic antiferromagnets

    Science.gov (United States)

    Yang, See-Hun; Parkin, Stuart

    2017-08-01

    In this article, we review fascinating new mechanisms on recently observed remarkable current driven domain wall motion in nanowires formed from perpendicularly magnetized synthetic antiferromagnets interfaced with heavy metallic layers, sources of spin-orbit torques. All the associated torques such as volumetric adiabatic and non-adiabatic spin-transfer-torque, spin-orbit torques, shape anisotropy field torques, Dzyaloshinkii-Moriya interaction torques and most importantly a new powerful torque, exchange coupling torque, will be discussed based on an analytical model that provides an intuitive description of domain wall dynamics in synthetic ferromagnets as well as synthetic antiferromagnets. In addition, the current driven DW motion in the presence of in-plane fields will be investigated, thus deepening our knowledge about the role of the exchange coupling torque, which will be of potential use for application to various novel spintronic devices.

  15. Finite Temperature Qcd With Domain Wall Fermions

    CERN Document Server

    Fleming, G T

    2001-01-01

    Domain wall fermions are a new lattice fermion formulation which preserves the full chiral symmetry of the continuum at finite lattice spacing, up to terms exponentially small in an extra parameter. We discuss the main features of the formulation and its application to study of QCD with two light fermions of equal mass. We also present numerical studies of the two flavor QCD thermodynamics with aT = 1/4.

  16. Topological Luttinger liquids from decorated domain walls

    Science.gov (United States)

    Parker, Daniel E.; Scaffidi, Thomas; Vasseur, Romain

    2018-04-01

    We introduce a systematic construction of a gapless symmetry-protected topological phase in one dimension by "decorating" the domain walls of Luttinger liquids. The resulting strongly interacting phases provide a concrete example of a gapless symmetry-protected topological (gSPT) phase with robust symmetry-protected edge modes. Using boundary conformal field theory arguments, we show that while the bulks of such gSPT phases are identical to conventional Luttinger liquids, their boundary critical behavior is controlled by a different, strongly coupled renormalization group fixed point. Our results are checked against extensive density matrix renormalization group calculations.

  17. Domain Wall Evolution in Phase Transforming Oxides

    Science.gov (United States)

    2015-01-14

    Domain wall motion and electric?field?induced strains in NBT ?xBT solid solutions from in situ neutron diffraction,” T.-M. Usher,* J. S. Forrester, E...Morphotropic Phase Boundary of NBT ?BT,” L. M. Denis,* J. Glaum, M. Hoffman, J. Forrester, and J. L. Jones, Electronic Materials and Applications 2013...titanate (PZT) and lead-free compositions Na0.5K0.5NbO3 (NKN) and Na0.5Bi0.5TiO3 ( NBT ). This past year, we reported results on piezoelectric compositions

  18. Origin of stationary domain wall enhanced ferroelectric susceptibility

    Science.gov (United States)

    Liu, Shi; Cohen, R. E.

    2017-03-01

    Ferroelectrics usually adopt a multidomain state with domain walls separating domains with polarization axes oriented differently. It has long been recognized that domain walls can dramatically impact the properties of ferroelectric materials. The enhancement of low-field susceptibility/permittivity under subswitching conditions is usually attributed to reversible domain wall vibration. Recent experiments highlight the stationary domain wall contribution to the dielectric susceptibility irrespective of any lateral displacements or deformations of the wall. We study the effects of domain walls on the low-field permittivity of PbTiO3 with density functional theory and molecular dynamics simulations. The static dielectric constant is calculated as a function of increasing domain wall density and temperature. We find an increase of dielectric permittivity with increasing domain wall density, which is expected to occur at a low driving field where the lateral motion of domain walls is forbidden. Real-space decomposition of the dielectric response reveals that frustrated dipoles within the finite width of the domain walls are responsible for the enhanced low-field permittivity. We explain the 100 % enhancement of the dielectric susceptibility form domain walls, which arises from the softer potential wells within them.

  19. Domain Wall Mobility in Co-Based Amorphous Wire

    Directory of Open Access Journals (Sweden)

    Maria Kladivova

    2007-01-01

    Full Text Available Dynamics of the domain wall between opposite circularly magnetized domains in amorphous cylindrical sample with circular easy direction is theoretically studied. The wall is driven by DC current. Various mechanisms which influence the wall velocity were taken into account: current magnitude, deformation of the mowing wall, Hall effect, axially magnetized domain in the middle of the wire. Theoretical results obtained are in a good agreement with experiments on Cobased amorphous ferromagnetic wires.

  20. Gravitational field of spherical domain wall in higher dimension

    Indian Academy of Sciences (India)

    An exact solution of Einstein's equations is found describing the gravitational field of a spherical domain wall with nonvanishing stress component in the direction perpendicular to the plane of the wall. Also we have studied the motion of test particle around the domain wall.

  1. Structure and Specificity of a Binary Tandem Domain F-Lectin from Striped Bass (Morone saxatilis)

    Energy Technology Data Exchange (ETDEWEB)

    Bianchet, M.; Odom, E; Vasta, J; Amzel, M

    2010-01-01

    The plasma of the striped bass Morone saxatilis contains a fucose-specific lectin (MsaFBP32) that consists of two F-type carbohydrate recognition domains (CRDs) in tandem. The crystal structure of the complex of MsaFBP32 with l-fucose reported here shows a cylindrical 81-A-long and 60-A-wide trimer divided into two globular halves: one containing N-terminal CRDs (N-CRDs) and the other containing C-terminal CRDs (C-CRDs). The resulting binding surfaces at the opposite ends of the cylindrical trimer have the potential to cross-link cell surface or humoral carbohydrate ligands. The N-CRDs and C-CRDs of MsaFBP32 exhibit significant structural differences, suggesting that they recognize different glycans. Analysis of the carbohydrate binding sites provides the structural basis for the observed specificity of MsaFBP32 for simple carbohydrates and suggests that the N-CRD recognizes more complex fucosylated oligosaccharides and with a relatively higher avidity than the C-CRD. Modeling of MsaFBP32 complexed with fucosylated glycans that are widely distributed in prokaryotes and eukaryotes rationalizes the observation that binary tandem CRD F-type lectins function as opsonins by cross-linking 'non-self' carbohydrate ligands and 'self' carbohydrate ligands, such as sugar structures displayed by microbial pathogens and glycans on the surface of phagocytic cells from the host.

  2. Spin accumulation and magnetoresistance of ferromagnetic domain walls

    Science.gov (United States)

    Dzero, Maxim; Gor'kov, Lev; Zvezdin, Anatolii; Zvezdin, Konstantin

    2003-03-01

    Taking into account the difference in the density of states between the spin's majority and minority bands in a ferromagnet, we obtain a spatial behavior of the electrostatic potential at the domain wall boundaries. The value of discontinuity oscillates with the number of domains and contains information about system as a whole, such as the positions of the domain walls or collapse of the domain walls when an external magnetic field is applied. We explain experimentally observed values of magnetoresistance in terms of spin accumulation effects. For the latter we suggest that in nanowires made of itinerant ferromagnets a new type of domain walls is realized, in which system prefers to reduce the value of magnetization rather then rotating it going from one domain to another. We also discuss the questions related to conditions of stability of linear domain walls.

  3. Antiphase boundaries, inversion, and ferroelastic domains in the striped-type superstructure of γ-brass Cu-Al alloys

    Science.gov (United States)

    Koyama, Y.; Hatano, M.; Tanimura, M.

    1996-05-01

    Features of the striped-type superstructure in γ-brass Cu-Al alloys have been investigated mainly by transmission electron microscopy in order to understand the role of a rhombohedral distortion in its stability. From dark field images taken from alloys exhibiting the superstructure, it was found that there exist two types of ferroelastic rhombohedral domains, which are in a twin relation. In other words, the superstructure is characterized by a periodic array of the ferroelastic domains as well as inversion antiphase boundaries. Because charge density waves should be responsible for the formation of the superstructure, as suggested in our previous paper [Phys. Rev. B 40, 5378 (1989)], the rhombohedral distortion must play a crucial role in their appearance. Presumably the distortion enlarges parallel portions of the Fermi surface. On the basis of the present experimental data, the interplay between the striped-type superstructure and the rhombohedral γ-brass structure is also discussed.

  4. Ratchet effect of the domain wall by asymmetric magnetostatic potentials

    Science.gov (United States)

    Piao, Hong-Guang; Choi, Hyeok-Cheol; Shim, Je-Ho; Kim, Dong-Hyun; You, Chun-Yeol

    2011-11-01

    We investigate a ratchet effect of magnetic domain wall motion in a ferromagnetic nanowire under AC magnetic fields using micromagnetic simulation. The ratchet effect for a transverse domain wall is achieved using an asymmetric magnetic potential generated by stray fields from non-contact trapezoidal ferromagnetic stubs near the straight nanowire. The ratchet phenomenon has been examined with various combinations of amplitude and frequency of the driving AC field. Interestingly, we find that the domain wall propagates along a preferential direction by the diode-like ratchet effect under AC field. The propagation of the domain wall strongly depends on the profile of the asymmetrical magnetic potentials and the driving AC field characteristics.

  5. A Cross Structured Light Sensor and Stripe Segmentation Method for Visual Tracking of a Wall Climbing Robot

    Science.gov (United States)

    Zhang, Liguo; Sun, Jianguo; Yin, Guisheng; Zhao, Jing; Han, Qilong

    2015-01-01

    In non-destructive testing (NDT) of metal welds, weld line tracking is usually performed outdoors, where the structured light sources are always disturbed by various noises, such as sunlight, shadows, and reflections from the weld line surface. In this paper, we design a cross structured light (CSL) to detect the weld line and propose a robust laser stripe segmentation algorithm to overcome the noises in structured light images. An adaptive monochromatic space is applied to preprocess the image with ambient noises. In the monochromatic image, the laser stripe obtained is recovered as a multichannel signal by minimum entropy deconvolution. Lastly, the stripe centre points are extracted from the image. In experiments, the CSL sensor and the proposed algorithm are applied to guide a wall climbing robot inspecting the weld line of a wind power tower. The experimental results show that the CSL sensor can capture the 3D information of the welds with high accuracy, and the proposed algorithm contributes to the weld line inspection and the robot navigation. PMID:26110403

  6. Second-harmonic imaging of ferroelectric domain walls

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Hvam, Jørn Märcher; Pedersen, Kjeld

    1998-01-01

    Domain walls in periodically poled ferroelectric KTiOPO4 and LiNbO3 crystals are observed by making use of second-harmonic (SH) generation enhancement in the transition regions between neighboring domains. SH images of domain walls obtained with various samples for different polarization...... configurations are presented. The SH generation enhancement is found especially pronounced for the polarization of the SH radiation being perpendicular to the domain walls. The origin and selection rules for the contrast in SH images of domain walls are discussed. The results obtained suggest that the domain...... walls produce a deteriorating effect on SH generation by quasiphase matching. (C) 1998 American Institute of Physics. [S0003-6951(98)02039-7]....

  7. Domain wall QCD with physical quark masses

    CERN Document Server

    Blum, T.; Christ, N.H.; Frison, J.; Garron, N.; Hudspith, R.J.; Izubuchi, T.; Janowski, T.; Jung, C.; Jüttner, A.; Kelly, C.; Kenway, R.D.; Lehner, C.; Marinkovic, M.; Mawhinney, R.D.; McGlynn, G.; Murphy, D.J.; Ohta, S.; Portelli, A.; Sachrajda, C.T.; Soni, A.

    2016-01-01

    We present results for several light hadronic quantities ($f_\\pi$, $f_K$, $B_K$, $m_{ud}$, $m_s$, $t_0^{1/2}$, $w_0$) obtained from simulations of 2+1 flavor domain wall lattice QCD with large physical volumes and nearly-physical pion masses at two lattice spacings. We perform a short, O(3)%, extrapolation in pion mass to the physical values by combining our new data in a simultaneous chiral/continuum `global fit' with a number of other ensembles with heavier pion masses. We use the physical values of $m_\\pi$, $m_K$ and $m_\\Omega$ to determine the two quark masses and the scale - all other quantities are outputs from our simulations. We obtain results with sub-percent statistical errors and negligible chiral and finite-volume systematics for these light hadronic quantities, including: $f_\\pi$ = 130.2(9) MeV; $f_K$ = 155.5(8) MeV; the average up/down quark mass and strange quark mass in the $\\bar {\\rm MS}$ scheme at 3 GeV, 2.997(49) and 81.64(1.17) MeV respectively; and the neutral kaon mixing parameter, $B_K$...

  8. Chiral damping of magnetic domain walls

    KAUST Repository

    Jué, Emilie

    2015-12-21

    Structural symmetry breaking in magnetic materials is responsible for the existence of multiferroics1, current-induced spin–orbit torques2, 3, 4, 5, 6, 7 and some topological magnetic structures8, 9, 10, 11, 12. In this Letter we report that the structural inversion asymmetry (SIA) gives rise to a chiral damping mechanism, which is evidenced by measuring the field-driven domain-wall (DW) motion in perpendicularly magnetized asymmetric Pt/Co/Pt trilayers. The DW dynamics associated with the chiral damping and those with Dzyaloshinskii–Moriya interaction (DMI) exhibit identical spatial symmetry13, 14, 15, 16, 17, 18, 19. However, both scenarios are differentiated by their time reversal properties: whereas DMI is a conservative effect that can be modelled by an effective field, the chiral damping is purely dissipative and has no influence on the equilibrium magnetic texture. When the DW motion is modulated by an in-plane magnetic field, it reveals the structure of the internal fields experienced by the DWs, allowing one to distinguish the physical mechanism. The chiral damping enriches the spectrum of physical phenomena engendered by the SIA, and is essential for conceiving DW and skyrmion devices owing to its coexistence with DMI (ref. 20).

  9. Spin motive forces due to magnetic vortices and domain walls

    NARCIS (Netherlands)

    Lucassen, M.E.; Kruis, G.C.F.L.; Lavrijsen, R.; Swagten, H.J.M.; Koopmans, B.; Duine, R.A.

    2011-01-01

    We study spin motive forces, that is, spin-dependent forces and voltages induced by time-dependent magnetization textures, for moving magnetic vortices and domain walls. First, we consider the voltage generated by a one-dimensional field-driven domain wall. Next, we perform detailed calculations on

  10. One loop calculation of QCD with domain-wall quarks

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, S.; Taniguchi, Y. [Tsukuba Univ., Sakura, Ibaraki (Japan). Inst. of Physics

    1998-04-01

    We calculate one loop corrections to the domain-wall quark propagator in QCD. We show how the wave function is renormalized in this theory. Especially we are interested in the behavior of the massless fermion mode, which exists near the domain wall at the tree level. We show that this massless mode is stable against the quantum correction. (orig.). 5 refs.

  11. On domain-wall/QFT dualities in various dimensions

    NARCIS (Netherlands)

    Behrndt, Klaus; Bergshoeff, Eric; Halbersma, Rein; Schaar, Jan Pieter van der

    1999-01-01

    We investigate domain-wall/quantum field-theory correspondences in various dimensions. Our general analysis covers not only the well studied cases in 10 and 11 dimensions, but also enables us to discuss new cases like a type I/heterotic 6-brane in 10 dimensions and domain-wall dualities in lower

  12. Control of Domain Wall Polarity by Current Pulses

    Science.gov (United States)

    Vanhaverbeke, A.; Bischof, A.; Allenspach, R.

    2008-09-01

    Direct observation of current-induced propagation of purely transverse magnetic domain walls with spin-polarized scanning electron microscopy is reported in Fe30Ni70 nanowires. After propagation, the domain walls keep their transverse nature but switch polarity in some cases. For uniform Ni70Fe30 wires, the effect is random and illustrates domain-wall propagation above the Walker threshold. In the case of Ni70Fe30/Fe wires, the transverse magnetization component in the wall is entirely determined by the polarity of the current pulse, an effect that is not reconciled by present theories even when taking into account the nonuniform Oersted field generated by the current.

  13. Contribution of domain wall networks to the CMB power spectrum

    Directory of Open Access Journals (Sweden)

    A. Lazanu

    2015-07-01

    Full Text Available We use three domain wall simulations from the radiation era to the late-time dark energy domination era based on the PRS algorithm to calculate the energy–momentum tensor components of domain wall networks in an expanding universe. Unequal time correlators in the radiation, matter and cosmological constant epochs are calculated using the scaling regime of each of the simulations. The CMB power spectrum of a network of domain walls is determined. The first ever quantitative constraint for the domain wall surface tension is obtained using a Markov chain Monte Carlo method; an energy scale of domain walls of 0.93 MeV, which is close but below the Zel'dovich bound, is determined.

  14. Investigation of domain walls in GMO crystals by conoscope method

    International Nuclear Information System (INIS)

    Radchenko, I.R.; Filimonova, L.A.

    1993-01-01

    The patterns of polarized beam interference (conoscopic patterns) enable assessment of orientation and parameters of crystal's optical indicatrix. The presented conoscopic patterns of gadolinium molybdate crystal in the vicinity to plane and wedge-live domain walls differ from conoscopic patterns of the crystals far away from these walls which allows to spear about changes occurring in the crystal in the vicinity to domain walls

  15. Checkerboard local density of states in striped domains pinned by vortices

    DEFF Research Database (Denmark)

    Andersen, B.M.; Hedegård, P.; Bruus, Henrik

    2003-01-01

    We discuss recent elastic neutron scattering and scanning tunneling experiments on high-T-c cuprates exposed to an applied magnetic field. Antiferromagnetic vortex cores operating as pinning centers for surrounding stripes is qualitatively consistent with the neutron data provided the stripes have...... the antiphase modulation. Within a Green's function formalism we study the low energy electronic structure around the vortices and find that besides the dispersive quantum interference there exists a non-dispersive checkerboard interference pattern consistent with recent scanning tunneling measurements. Thus...

  16. SAW assisted domain wall motion in Co/Pt multilayers

    Science.gov (United States)

    Edrington, Westin; Singh, Uday; Dominguez, Maya Abo; Alexander, James Rehwaldt; Nepal, Rabindra; Adenwalla, S.

    2018-01-01

    The motion of domain walls in thin ferromagnetic films is of both fundamental and technological interest. In particular, the ability to use drivers other than magnetic fields to control the positions of domain walls could be exciting for memory applications. Here, we show that high frequency dynamic strain produced by surface acoustic waves is an efficient driver of magnetic domain walls in ferromagnetic films with perpendicular anisotropy. A standing surface acoustic wave of resonant frequency 96.6 MHz increases the domain wall velocities in thin films of [Co/Pt]n by an order of magnitude compared to magnetic fields alone. This effect is highly resonant, effectively ruling out thermal effects, and the velocity shows distinct variations in the domain wall velocity at the nodes and antinodes of the standing wave. The data indicate that standing strain waves can drive the domain wall motion from the creep to the flow regime as the amplitude increases. Hence, strain waves could provide an alternative route to rapid domain wall motion.

  17. Bichiral structure of ferroelectric domain walls driven by flexoelectricity

    Science.gov (United States)

    Yudin, P. V.; Tagantsev, A. K.; Eliseev, E. A.; Morozovska, A. N.; Setter, N.

    2012-10-01

    The influence of flexoelectric coupling on the internal structure of neutral domain walls in the tetragonal phase of perovskite ferroelectrics is studied. The effect is shown to lower the symmetry of 180∘ walls which are oblique with respect to the cubic crystallographic axes, while {100} and {110} walls stay “untouched.” Being of the Ising type in the absence of the flexoelectric interaction, the oblique domain walls acquire a new polarization component with a structure qualitatively different from the classical Bloch-wall structure. In contrast to the Bloch-type walls, where the polarization vector draws a helix on passing from one domain to the other, in the flexoeffect-affected wall, the polarization rotates in opposite directions on the two sides of the wall and passes through zero in its center. Since the resulting polarization profile is invariant upon inversion with respect to the wall center, it does not break the wall symmetry, in contrast to the classical Bloch-type walls. The flexoelectric coupling lowers the domain wall energy and gives rise to its additional anisotropy, which is comparable to that conditioned by elastic anisotropy. The atomic order-of-magnitude estimates shows that the new polarization component P2 may be comparable with spontaneous polarization Ps, thus suggesting that, in general, it is mandatory to include the flexoelectric coupling in domain wall simulations in ferroelectrics. Calculations performed for barium titanate yield the maximal value of P2, which is much smaller than that of the spontaneous polarization. This smallness is attributed to an anomalously small value of a component of the “strain-polarization” electrostrictive tensor in this material.

  18. Even-odd effects in magnetoresistance of ferromagnetic domain walls

    Science.gov (United States)

    Dzero, M.; Gor'kov, L. P.; Zvezdin, A. K.; Zvezdin, K. A.

    2003-03-01

    The difference in the density of states for the spin’s majority and minority bands in a ferromagnet changes the electrostatic potential along the domains, introducing discontinuities of the potential at domain boundaries. The value of the discontinuity oscillates with the number of domains. Discontinuity depends on the positions of domain walls, their motion, or the collapse of domain walls in applied magnetic field. Large values of the magnetoresistance are explained in terms of spin accumulation. We suggest a type of domain wall in nanowires made of itinerant ferromagnets, in which the magnetization vector changes without rotation. The absence of transverse magnetization components allows considerable spin accumulation, assuming the spin relaxation length LS is large enough.

  19. Gravitational waves from domain walls and their implications

    Directory of Open Access Journals (Sweden)

    Kazunori Nakayama

    2017-07-01

    Full Text Available We evaluate the impact of domain-wall annihilation on the currently ongoing and planned gravitational wave experiments, including a case in which domain walls experience a frictional force due to interactions with the ambient plasma. We show the sensitivity reach in terms of physical parameters, namely, the wall tension and the annihilation temperature. We find that a Higgs portal scalar, which stabilizes the Higgs potential at high energy scales, can form domain walls whose annihilation produces a large amount of gravitational waves within the reach of the advanced LIGO experiment (O5. Domain wall annihilation can also generate baryon asymmetry if the scalar is coupled to either SU(2L gauge fields or the (B−L current. This is a variant of spontaneous baryogenesis, but it naturally avoids the isocurvature constraint due to the scaling behavior of the domain-wall evolution. We delineate the parameter space where the domain-wall baryogenesis works successfully and discuss its implications for the gravitational wave experiments.

  20. Domain-wall trapping in a ferromagnetic nanowire network

    Science.gov (United States)

    Saitoh, E.; Tanaka, M.; Miyajima, H.; Yamaoka, T.

    2003-05-01

    The magnetic domain configuration in a submicron Ni81Fe19 wire network has been investigated by magnetic force microscopy. To improve the responsivity of the magnetic force microscope, an active quality factor autocontrol method was adopted. In the remanent state, domain walls were observed trapped firmly at the vertexes of the network. The magnetic domain configurations appear to minimize the exchange energy at the vertexes. These results indicate that the magnetic property of the ferromagnetic network can be described in terms of the uniform magnetic moments of the wires and interwire magnetic interactions at the vertexes. The observed structure of the domain walls is well reproduced by micromagnetic simulations.

  1. Scalar triplet on a domain wall: an exact solution

    Energy Technology Data Exchange (ETDEWEB)

    Gani, Vakhid A. [Department of Mathematics,National Research Nuclear University MEPhI (Moscow Engineering Physics Institute),115409 Moscow (Russian Federation); Theory Department, National Research Center Kurchatov Institute,Institute for Theoretical and Experimental Physics, 117218 Moscow (Russian Federation); Lizunova, Mariya A. [Theory Department, National Research Center Kurchatov Institute,Institute for Theoretical and Experimental Physics, 117218 Moscow (Russian Federation); Department of Theoretical Nuclear Physics,National Research Nuclear University MEPhI (Moscow Engineering Physics Institute),115409 Moscow (Russian Federation); Radomskiy, Roman V. [Department of Elementary Particle Physics,National Research Nuclear University MEPhI (Moscow Engineering Physics Institute),115409 Moscow (Russian Federation)

    2016-04-07

    We study a model with a real scalar Higgs field and a scalar triplet field that allows existence of a topological defect — a domain wall. The wall breaks the global O(3) symmetry of the model, which gives rise to non-Abelian orientational degrees of freedom. We found an exact analytic solution that describes a domain wall with a localized configuration of the triplet field on it. This solution enables one to calculate contributions to the action from the orientational and translational degrees of freedom of the triplet field. We also study the linear stability of the domain wall with the triplet field switched off. We obtain that degrees of freedom localized on the wall can appear or do not appear depending on the parameters of the model.

  2. Current driven domain wall motion in ferrimagnetic Heusler thin racetracks

    Science.gov (United States)

    Filippou, Panagiotis; Jeong, Jaewoo; Yang, See-Hun; Ferrante, Yari; Topuria, Teya; Samant, Mahesh; Parkin, Stuart

    Heusler compounds are a large family of materials with a wide range of tunable properties. Of particular interest are ferrimagnetic binary Heusler compounds that have low magnetization and high perpendicular magnetic anisotropy in their tetragonally distorted forms. We have investigated a number of binary Mn based Heusler compounds and have prepared ultrathin films with thicknesses ranging from 1 to several unit cells. By forming racetracks from these materials we have demonstrated, for the first time, the current induced motion of domain walls with speeds up to 106 m/sec. We discuss the mechanisms by which the domain walls are moved with current which we find is surprisingly complex. Ferrimagnetic Heuslers are particularly interesting for spintronic applications because their low moment and high anisotropy allow for very narrow domain walls and, therefore, dense applications. We estimate the domain wall widths are of the order of a few unit cells.

  3. Runaway domain wall and space-time varying α

    International Nuclear Information System (INIS)

    Chiba, Takeshi; Yamaguchi, Masahide

    2011-01-01

    Recently spatial as well as temporal variations of the fine structure constant α have been reported. We show that a ''runaway domain wall , which arises for the scalar field potential without minima, can account for such variations simultaneously. The time variation is induced by a runaway potential and the spatial variation is induced by the formation of a domain wall. The model is consistent with the current cosmological data and can be tested by the future experiments to test the equivalence principle

  4. Axially symmetric domain wall in 2+1-dimensions

    International Nuclear Information System (INIS)

    Soda, Jiro; Yamanaka, Yuki.

    1991-04-01

    An axially symmetric domain wall (string) in 2+1-dimensions is investigated in the synchronous gauge. This problem is also regarded as a cylindrical symmetric domain wall (membrane) in 3+1-dimensions. Using Israel's method, we present a general solution. As a special case, a static solution is obtained which agrees with the previous result of Deser and Jackiw obtained by another method. (author)

  5. Magnetic domain wall conduits for single cell applications

    DEFF Research Database (Denmark)

    Donolato, Marco; Torti, A.; Kostesha, Natalie

    2011-01-01

    The ability to trap, manipulate and release single cells on a surface is important both for fundamental studies of cellular processes and for the development of novel lab-on-chip miniaturized tools for biological and medical applications. In this paper we demonstrate how magnetic domain walls...... walls technology in lab-on-chip systems devoted to accurate individual cell trapping and manipulation....

  6. Axion-dilaton domain walls and fake supergravity

    International Nuclear Information System (INIS)

    Sonner, Julian; Townsend, Paul K

    2007-01-01

    Dynamical systems methods are used to investigate domain-wall solutions of a two-parameter family of models in which gravity is coupled to an axion and to a dilaton with an exponential potential of either sign. A complete global analysis is presented for (i) constant axion and (ii) flat walls, including a study of bifurcations and a new exact domain-wall solution with non-constant axion. We reconsider 'fake-supergravity' issues in light of these results. We show, by example, how domain walls determine multi-valued superpotentials that branch at stationary points that are not stationary points of the potential, and we apply this result to potentials with anti-de Sitter vacua. We also show by example that 'adapted' truncation to a single-scalar model may be inconsistent, and we propose a 'generalized' fake-supergravity formalism that applies in some such cases

  7. Dynamics of cylindrical domain walls in smectic C liquid crystals

    International Nuclear Information System (INIS)

    Stewart, I W; Wigham, E J

    2009-01-01

    An analysis of the dynamics of cylindrical domain walls in planar aligned samples of smectic C liquid crystals is presented. A circular magnetic field, induced by an electric current, drives a time-dependent reorientation of the corresponding radially dependent director field. Nonlinear approximations to the relevant nonlinear dynamic equation, derived from smectic continuum theory, are solved in a comoving coordinated frame: exact solutions are found for a π-wall and numerical solutions are calculated for π/2-walls. Each calculation begins with an assumed initial state for the director that is a prescribed cylindrical domain wall. Such an initial wall will proceed to expand or contract as its central core propagates radially inwards or outwards, depending on the boundary conditions for the director, the elastic constants, the magnitude of the field and the sign of the magnetic anisotropy of the liquid crystal

  8. Webs of domain walls in supersymmetric gauge theories

    International Nuclear Information System (INIS)

    Eto, Minoru; Isozumi, Youichi; Nitta, Muneto; Ohashi, Keisuke; Sakai, Norisuke

    2005-01-01

    Webs of domain walls are constructed as 1/4 Bogomol'nyi-Prasad-Sommerfield (BPS) states in d=4, N=2 supersymmetric U(N C ) gauge theories with N F hypermultiplets in the fundamental representation. Webs of walls can contain any numbers of external legs and loops like (p,q) string/5-brane webs. We find the moduli space M of a 1/4 BPS equation for wall webs to be the complex Grassmann manifold. When moduli spaces of 1/2 BPS states (parallel walls) and the vacua are removed from M, the noncompact moduli space of genuine 1/4 BPS wall webs is obtained. All the solutions are obtained explicitly and exactly in the strong gauge coupling limit. In the case of Abelian gauge theory, we work out the correspondence between configurations of wall web and the moduli space CP N F -1

  9. Domain walls and ferroelectric reversal in corundum derivatives

    Science.gov (United States)

    Ye, Meng; Vanderbilt, David

    2017-01-01

    Domain walls are the topological defects that mediate polarization reversal in ferroelectrics, and they may exhibit quite different geometric and electronic structures compared to the bulk. Therefore, a detailed atomic-scale understanding of the static and dynamic properties of domain walls is of pressing interest. In this work, we use first-principles methods to study the structures of 180∘ domain walls, both in their relaxed state and along the ferroelectric reversal pathway, in ferroelectrics belonging to the family of corundum derivatives. Our calculations predict their orientation, formation energy, and migration energy and also identify important couplings between polarization, magnetization, and chirality at the domain walls. Finally, we point out a strong empirical correlation between the height of the domain-wall-mediated polarization reversal barrier and the local bonding environment of the mobile A cations as measured by bond-valence sums. Our results thus provide both theoretical and empirical guidance for future searches for ferroelectric candidates in materials of the corundum derivative family.

  10. Majorana Fermion Rides on a Magnetic Domain Wall

    Science.gov (United States)

    Kim, Se Kwon; Tewari, Sumanta; Tserkovnyak, Yaroslav

    Owing to the recent progress on endowing the electronic structure of magnetic nanowires with topological properties, the associated topological solitons in the magnetic texture--magnetic domain walls--appear as very natural hosts for exotic electronic excitations. Here, we propose to use the magnetic domain walls to engender Majorana fermions, which has several notable advantages compared to the existing approaches. First of all, the local tunneling density-of-states anomaly associated with the Majorana zero mode bound to a smooth magnetic soliton is immune to most of parasitic artifacts associated with the abrupt physical ends of a wire, which mar the existing experimental probes. Second, a viable route to move and braid Majorana fermions is offered by domain-wall motion. In particular, we envision the recently demonstrated heat-current induced motion of domain walls in insulating ferromagnets as a promising tool for nonintrusive displacement of Majorana modes. This leads us to propose a feasible scheme for braiding domain walls within a magnetic nanowire network, which manifests the nob-Abelian exchange statistics within the Majorana subspace. This work has been supported in part by the U.S. DOE-BES, FAME, and AFOSR grants.

  11. Implementation of one-dimensional domain wall dynamics simulator

    Science.gov (United States)

    Kim, Hyungsuk; Heo, Seo Weon; You, Chun-Yeol

    2017-12-01

    We implemented a one-dimensional domain wall (DW) dynamics simulator based on the well-developed collective coordinate approach to demonstrate DW motion under a given magnetic field and/or current flow. The simulator adopted all known influences, including three-dimensional external magnetic fields, spin transfer torque with non-adiabatic contribution, spin Hall effect, Rashba effect, and Dzyaloshinskii-Moriya interaction. The simulator can calculate the position, velocity, internal magnetization angle, and tilting angle of the domain wall to the current direction or wire axis under given simulation conditions and material parameters. It will not only provide physical insights of domain wall dynamics to experimentalists, but also can be used to more easily simulate various physical circumstances before running time-consuming micromagnetic simulations or real experiments.

  12. Highly efficient domain wall motion in ferrimagnetic trilayers

    Science.gov (United States)

    Yang, See-Hun; Garg, Chirag; Parkin, Stuart; IBM-MPI spintronics Team

    The current-induced domain wall motion arising from chiral spin torque forms the basis of a number of technologies such as the racetrack memory and 3-terminal based MRAM devices. One of the main impediments towards this implementation is the high current density usually needed to move domain walls reliably. Here, we show that in ferrimagnetic trilayers, we can reduce the critical current required to move domain walls by 2-5 times compared to a ferromagnetic trilayer while dramatically increasing the velocity for the same current densities. This in part, is effected by the use of a Pt underlayer which is grown as a mixture of (111) and (100) phase, resulting in a 50% greater Slonczewski-like SOT compared to (111) Pt, as measured by harmonic Hall voltage measurements of current-induced effective fields.

  13. Submicrometric 2D ratchet effect in magnetic domain wall motion

    Energy Technology Data Exchange (ETDEWEB)

    Castán-Guerrero, C., E-mail: ccastan@unizar.es [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Herrero-Albillos, J. [Fundación ARAID, E-50004 Zaragoza (Spain); Centro Universitario de la Defensa, E-50090 Zaragoza (Spain); Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Sesé, J. [Instituto de Nanociencia de Aragón, Laboratorio de Microscopías Avanzadas, Universidad de Zaragoza, E-50018 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Bartolomé, J.; Bartolomé, F. [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Hierro-Rodriguez, A.; Valdés-Bango, F.; Martín, J.I.; Alameda, J.M. [Dpto. Física, Universidad de Oviedo, Asturias (Spain); CINN (CSIC – Universidad de Oviedo – Principado de Asturias), Asturias (Spain); García, L.M. [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain)

    2014-12-15

    Strips containing arrays of submicrometric triangular antidots with a 2D square periodicity have been fabricated by electron beam lithography. A clear ratchet effect of 180° domain wall motion under a varying applied field parallel to the walls has been observed. The direction is determined by the direction of the triangle vertices. In contrast, no ratchet effect is observed when the antidot array is constituted by symmetric rhomb-shaped antidots.

  14. Pseudo-Supersymmetry and the Domain-Wall/Cosmology Correspondence

    OpenAIRE

    Skenderis, K.; Townsend, P. K.

    2006-01-01

    The correspondence between domain-wall and cosmological solutions of gravity coupled to scalar fields is explained. Any domain wall solution that admits a Killing spinor is shown to correspond to a cosmology that admits a pseudo-Killing spinor: whereas the Killing spinor obeys a Dirac-type equation with hermitian `mass'-matrix, the corresponding pseudo-Killing spinor obeys a Dirac-type equation with a anti-hermitian `mass'-matrix. We comment on some implications of (pseudo)supersymmetry.

  15. NMR and domain wall mobility in intermetallic compounds

    International Nuclear Information System (INIS)

    Guimaraes, A.P.; Sampaio, L.C.; Cunha, S.F.; Alves, K.M.B.

    1991-01-01

    The technique of pulsed NMR can be used to study the distribution of hyperfine fields in a magnetic matrix. The dynamics of the domain walls are relevant to the generation of NMR signals. In the present study on the (R x Y 1-x ) Fe 2 intermetallic compounds, the reduction in the signals is associated to increased propagation fields. This indicates that a smaller domain wall mobility is at the origin of these effects. NMR spectra in this system show the importance of direct and indirect (i.e., mediated by Fe atoms) terms in the transferred hyperfine field. (author)

  16. Domain Walls and Matter-Antimatter Domains in the Early Universe

    Directory of Open Access Journals (Sweden)

    Dolgov A.D.

    2017-01-01

    Full Text Available We suggest a scenario of spontaneous (or dynamical C and CP violation according to which it is possible to generate domains of matter and antimatter separated by cosmologically large distances. Such C(CP violation existed only in the early universe and later it disappeared with the only trace of generated matter and antimatter domains. So this scenario does not suffer from the problem of domain walls. According to this scenario the width of the domain wall should grow exponentially to prevent annihilation at the domain boundaries. Though there is a classical result obtained by Basu and Vilenkin that the width of the wall tends to the one of the stationary solution (constant physical width. That is why we considered thick domain walls in a de Sitter universe following paper by Basu and Vilenkin. However, we were interested not only in stationary solutions found therein, but also investigated the general case of domain wall evolution with time. When the wall thickness parameter, δ0 , is smaller than H−1/2 where H is the Hubble parameter in de Sitter space-time, then the stationary solutions exist, and initial field configurations tend with time to the stationary ones. However, there are no stationary solutions for δ0>H−1/2 We have calculated numerically the rate of the wall expansion in this case and have found that the width of the wall grows exponentially fast for δ0≫H−1 An explanation for the critical value δ0c=H−1/2 is also proposed.

  17. Conduction through 71 degrees DomainWalls in BiFeO3 Thin Films

    NARCIS (Netherlands)

    Farokhipoor, S.; Noheda, Beatriz

    2011-01-01

    Local conduction at domains and domain walls is investigated in BiFeO3 thin films containing mostly 71 degrees domain walls. Measurements at room temperature reveal conduction through 71 degrees domain walls. Conduction through domains could also be observed at high enough temperatures. It is found

  18. Casimir densities for parallel plate in the domain wall background

    International Nuclear Information System (INIS)

    Setare, M R

    2003-01-01

    The Casimir forces on two parallel plates in the conformally flat domain wall background due to a conformally coupled massless scalar field satisfying mixed boundary conditions on the plates are investigated. In the general case of mixed boundary conditions, formulae are derived for the vacuum expectation values of the energy-momentum tensor and vacuum forces acting on the boundaries

  19. Gravitational field of spherical domain wall in higher dimension

    Indian Academy of Sciences (India)

    and examine whether bound orbits are possible or not. This study will be of relevance to the structure formation because it gives some idea about the behaviour of the particles. (created at the early universe) in the gravitational field of the domain walls. Our paper is organized as follows: The basic equations are constructed ...

  20. On domain wall boundary conditions for the XXZ spin Hamiltonian

    DEFF Research Database (Denmark)

    Orlando, Domenico; Reffert, Susanne; Reshetikhin, Nicolai

    In this note, we derive the spectrum of the infinite quantum XXZ spin chain with domain wall boundary conditions. The eigenstates are constructed as limits of Bethe states for the finite XXZ spin chain with quantum sl(2) invariant boundary conditions....

  1. The Quantum Noise of Ferromagnetic π-Bloch Domain Walls

    Directory of Open Access Journals (Sweden)

    Peter R. Crompton

    2009-09-01

    Full Text Available We quantify the probability per unit Euclidean-time of reversing the magnetization of a π-Bloch vector, which describes the Ferromagnetic Domain Walls of a Ferromagnetic Nanowire at finite-temperatures. Our approach, based on Langer’s Theory, treats the double sine-Gordon model that defines the π-Bloch vectors via a procedure of nonperturbative renormalization, and uses importance sampling methods to minimise the free energy of the system and identify the saddlepoint solution corresponding to the reversal probability. We identify that whilst the general solution for the free energy minima cannot be expressed in closed form, we can obtain a closed expression for the saddlepoint by maximizing the entanglement entropy of the system as a polynomial ring. We use this approach to quantify the geometric and non-geometric contributions to the entanglement entropy of the Ferromagnetic Nanowire, defined between entangled Ferromagnetic Domain Walls, and evaluate the Euclidean-time dependence of the domain wall width and angular momentum transfer at the domain walls, which has been recently proposed as a mechanism for Quantum Memory Storage.

  2. Matter antimatter domains: A possible solution to the CP domain wall problem in the early universe

    Science.gov (United States)

    Mohanty, A. K.; Stecker, F. W.

    1984-01-01

    An SU(5) grand unified theory model is used to show how the degeneracy between vacua with different spontaneously broken charge parity can be dynamically lifted by a condensate of heavy fermion pairs. This drives a phase transition to a unique vacuum state with definite charge parity. The transition eliminates the domain walls in a matter antimatter symmetric domain cosmology.

  3. Actin Cytoskeleton and Golgi Involvement in Barley stripe mosaic virus Movement and Cell Wall Localization of Triple Gene Block Proteins

    Directory of Open Access Journals (Sweden)

    Hyoun-Sub Lim

    2013-03-01

    Full Text Available Barley stripe mosaic virus (BSMV induces massive actin filament thickening at the infection front of infected Nicotiana benthamiana leaves. To determine the mechanisms leading to actin remodeling, fluorescent protein fusions of the BSMV triple gene block (TGB proteins were coexpressed in cells with the actin marker DsRed: Talin. TGB ectopic expression experiments revealed that TGB3 is a major elicitor of filament thickening, that TGB2 resulted in formation of intermediate DsRed:Talin filaments, and that TGB1 alone had no obvious effects on actin filament structure. Latrunculin B (LatB treatments retarded BSMV cell-to-cell movement, disrupted actin filament organization, and dramatically decreased the proportion of paired TGB3 foci appearing at the cell wall (CW. BSMV infection of transgenic plants tagged with GFP-KDEL exhibited membrane proliferation and vesicle formation that were especially evident around the nucleus. Similar membrane proliferation occurred in plants expressing TGB2 and/or TGB3, and DsRed: Talin fluorescence in these plants colocalized with the ER vesicles. TGB3 also associated with the Golgi apparatus and overlapped with cortical vesicles appearing at the cell periphery. Brefeldin A treatments disrupted Golgi and also altered vesicles at the CW, but failed to interfere with TGB CW localization. Our results indicate that actin cytoskeleton interactions are important in BSMV cell-to-cell movement and for CW localization of TGB3.

  4. Highly-reliable operation of 638-nm broad stripe laser diode with high wall-plug efficiency for display applications

    Science.gov (United States)

    Yagi, Tetsuya; Shimada, Naoyuki; Nishida, Takehiro; Mitsuyama, Hiroshi; Miyashita, Motoharu

    2013-03-01

    Laser based displays, as pico to cinema laser projectors have gathered much attention because of wide gamut, low power consumption, and so on. Laser light sources for the displays are operated mainly in CW, and heat management is one of the big issues. Therefore, highly efficient operation is necessitated. Also the light sources for the displays are requested to be highly reliable. 638 nm broad stripe laser diode (LD) was newly developed for high efficiency and highly reliable operation. An AlGaInP/GaAs red LD suffers from low wall plug efficiency (WPE) due to electron overflow from an active layer to a p-cladding layer. Large optical confinement factor (Γ) design with AlInP cladding layers is adopted to improve the WPE. The design has a disadvantage for reliable operation because the large Γ causes high optical density and brings a catastrophic optical degradation (COD) at a front facet. To overcome the disadvantage, a window-mirror structure is also adopted in the LD. The LD shows WPE of 35% at 25°C, highest record in the world, and highly stable operation at 35°C, 550 mW up to 8,000 hours without any catastrophic optical degradation.

  5. Performance of synthetic antiferromagnetic racetrack memory: domain wall versus skyrmion

    KAUST Repository

    Tomasello, R

    2017-06-20

    A storage scheme based on racetrack memory, where the information can be coded in a domain or a skyrmion, seems to be an alternative to conventional hard disk drive for high density storage. Here, we perform a full micromagnetic study of the performance of synthetic antiferromagnetic (SAF) racetrack memory in terms of velocity and sensitivity to defects by using experimental parameters. We find that, to stabilize a SAF skyrmion, the Dzyaloshinskii–Moriya interaction in the top and the bottom ferromagnet should have an opposite sign. The velocity of SAF skyrmions and SAF Néel domain walls are of the same order and can reach values larger than 1200 m s−1 if a spin–orbit torque from the spin-Hall effect with opposite sign is applied to both ferromagnets. The presence of disordered anisotropy in the form of randomly distributed grains introduces a threshold current for both SAF skyrmions and SAF domain walls motions.

  6. Primordial black hole and wormhole formation by domain walls

    Science.gov (United States)

    Deng, Heling; Garriga, Jaume; Vilenkin, Alexander

    2017-04-01

    In theories with a broken discrete symmetry, Hubble sized spherical domain walls may spontaneously nucleate during inflation. These objects are subsequently stretched by the inflationary expansion, resulting in a broad distribution of sizes. The fate of the walls after inflation depends on their radius. Walls smaller than a critical radius fall within the cosmological horizon early on and collapse due to their own tension, forming ordinary black holes. But if a wall is large enough, its repulsive gravitational field becomes dominant much before the wall can fall within the cosmological horizon. In this ``supercritical'' case, a wormhole throat develops, connecting the ambient exterior FRW universe with an interior baby universe, where the exponential growth of the wall radius takes place. The wormhole pinches off in a time-scale comparable to its light-crossing time, and black holes are formed at its two mouths. As discussed in previous work, the resulting black hole population has a wide distribution of masses and can have significant astrophysical effects. The mechanism of black hole formation has been previously studied for a dust-dominated universe. Here we investigate the case of a radiation-dominated universe, which is more relevant cosmologically, by using numerical simulations in order to find the initial mass of a black hole as a function of the wall size at the end of inflation. For large supercritical domain walls, this mass nearly saturates the upper bound according to which the black hole cannot be larger than the cosmological horizon. We also find that the subsequent accretion of radiation satisfies a scaling relation, resulting in a mass increase by about a factor of 2.

  7. Primordial black hole and wormhole formation by domain walls

    International Nuclear Information System (INIS)

    Deng, Heling; Garriga, Jaume; Vilenkin, Alexander

    2017-01-01

    In theories with a broken discrete symmetry, Hubble sized spherical domain walls may spontaneously nucleate during inflation. These objects are subsequently stretched by the inflationary expansion, resulting in a broad distribution of sizes. The fate of the walls after inflation depends on their radius. Walls smaller than a critical radius fall within the cosmological horizon early on and collapse due to their own tension, forming ordinary black holes. But if a wall is large enough, its repulsive gravitational field becomes dominant much before the wall can fall within the cosmological horizon. In this ''supercritical'' case, a wormhole throat develops, connecting the ambient exterior FRW universe with an interior baby universe, where the exponential growth of the wall radius takes place. The wormhole pinches off in a time-scale comparable to its light-crossing time, and black holes are formed at its two mouths. As discussed in previous work, the resulting black hole population has a wide distribution of masses and can have significant astrophysical effects. The mechanism of black hole formation has been previously studied for a dust-dominated universe. Here we investigate the case of a radiation-dominated universe, which is more relevant cosmologically, by using numerical simulations in order to find the initial mass of a black hole as a function of the wall size at the end of inflation. For large supercritical domain walls, this mass nearly saturates the upper bound according to which the black hole cannot be larger than the cosmological horizon. We also find that the subsequent accretion of radiation satisfies a scaling relation, resulting in a mass increase by about a factor of 2.

  8. Sequential injection of domain walls into ferroelectrics at different bias voltages: Paving the way for “domain wall memristors”

    Energy Technology Data Exchange (ETDEWEB)

    Whyte, J. R.; McQuaid, R. G. P.; Einsle, J. F.; Gregg, J. M., E-mail: m.gregg@qub.ac.uk [Centre for Nanostructured Media (CNM), School of Maths and Physics, Queen' s University Belfast, University Road, Belfast BT7 1NN (United Kingdom); Ashcroft, C. M. [Centre for Nanostructured Media (CNM), School of Maths and Physics, Queen' s University Belfast, University Road, Belfast BT7 1NN (United Kingdom); Department of Physics, Cavendish Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Canalias, C. [Department of Applied Physics, Royal Institute of Technology, Roslagstullsbacken 21, 10691 Stockholm (Sweden); Gruverman, A. [Department of Physics and Astronomy, University of Nebraska Lincoln, Nebraska 68588–0299 (United States)

    2014-08-14

    Simple meso-scale capacitor structures have been made by incorporating thin (∼300 nm) single crystal lamellae of KTiOPO{sub 4} (KTP) between two coplanar Pt electrodes. The influence that either patterned protrusions in the electrodes or focused ion beam milled holes in the KTP have on the nucleation of reverse domains during switching was mapped using piezoresponse force microscopy imaging. The objective was to assess whether or not variations in the magnitude of field enhancement at localised “hot-spots,” caused by such patterning, could be used to both control the exact locations and bias voltages at which nucleation events occurred. It was found that both the patterning of electrodes and the milling of various hole geometries into the KTP could allow controlled sequential injection of domain wall pairs at different bias voltages; this capability could have implications for the design and operation of domain wall electronic devices, such as memristors, in the future.

  9. Trajectory of dynamically propagating magnetic domain walls at nanowire vertices

    Science.gov (United States)

    Burn, David M.; Walton, Stephanie K.; Chadha, Megha; Zeissler, Katharina; Cohen, Lesley F.; Branford, Will R.; Functional magnetism Team

    2014-03-01

    Nanoscale patterning techniques can be used to fabricate magnetic nanowire structures where the behavior of individual magnetic domain walls (DWs) can be investigated. In addition to the fundamental physical understanding of magnetism, research in this area is also driven by the potential to realize novel spintronic devices for technological applications. Magnetic DWs can support a wide variety of micromagnetic structures with different magnetization, chirality and topology based on their interaction with the nanostructure geometry. These interactions can govern the field dependent domain wall trajectory and subsequent magnetization reversal that takes place within nanowire vertex structures. In this work the additional factors affecting the trajectory due to the dynamic behavior of propagating DWs are investigated. This includes the time dependent periodic changes in the DW micromagnetic structure from Walker breakdown. These results have implications for future technological applications as well as suggesting processes that may govern magnetization reversal in artificial spin ice structures.

  10. Fermion condensation and gapped domain walls in topological orders

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Yidun [Department of Physics and Center for Field Theory and Particle Physics, Fudan University,Shanghai 200433 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing University,Nanjing 210093 (China); Perimeter Institute for Theoretical Physics,Waterloo N2L 2Y5, Ontario (Canada); Wang, Chenjie [Perimeter Institute for Theoretical Physics,Waterloo N2L 2Y5, Ontario (Canada)

    2017-03-31

    We study fermion condensation in bosonic topological orders in two spatial dimensions. Fermion condensation may be realized as gapped domain walls between bosonic and fermionic topological orders, which may be thought of as real-space phase transitions from bosonic to fermionic topological orders. This picture generalizes the previous idea of understanding boson condensation as gapped domain walls between bosonic topological orders. While simple-current fermion condensation was considered before, we systematically study general fermion condensation and show that it obeys a Hierarchy Principle: a general fermion condensation can always be decomposed into a boson condensation followed by a minimal fermion condensation. The latter involves only a single self-fermion that is its own anti-particle and that has unit quantum dimension. We develop the rules of minimal fermion condensation, which together with the known rules of boson condensation, provides a full set of rules for general fermion condensation.

  11. Dimensional reduction, magnetic flux strings, and domain walls

    Science.gov (United States)

    Fosco1, C. D.; López1, A.; Schaposnik2, F. A.

    2000-08-01

    We study some consequences of dimensionally reducing systems with massless fermions and Abelian gauge fields from 3+1 to 2+1 dimensions. We first consider fermions in the presence of an external Abelian gauge field. In the reduced theory, obtained by compactifying one of the coordinates "a la Kaluza-Klein", magnetic flux strings are mapped into domain wall defects. Fermionic zero modes, localized around the flux strings of the 3+1 dimensional theory, become also zero modes in the reduced theory, via the Callan and Harvey mechanism, and are concentrated around the domain wall defects. We also study a dynamical model: massless QED 4, with fermions confined to a plane, deriving the effective action that describes the "planar" system.

  12. Domain wall universe in the Einstein-Born-Infeld theory

    International Nuclear Information System (INIS)

    Lee, Bum-Hoon; Lee, Wonwoo; Minamitsuji, Masato

    2009-01-01

    In this Letter, we discuss the dynamics of a domain wall universe embedded into the charged black hole spacetime of the Einstein-Born-Infeld (EBI) theory. There are four kinds of possible spacetime structures, i.e., those with no horizon, the extremal one, those with two horizons (as the Reissner-Nordstroem black hole), and those with a single horizon (as the Schwarzshild black hole). We derive the effective cosmological equations on the wall. In contrast to the previous works, we take the contribution of the electrostatic energy on the wall into account. By examining the properties of the effective potential, we find that a bounce can always happen outside the (outer) horizon. For larger masses of the black hole, the height of the barrier between the horizon and bouncing point in the effective potential becomes smaller, leading to longer time scales of bouncing process. These results are compared with those in the previous works.

  13. Quenched scalar-meson correlator with domain wall fermions

    Energy Technology Data Exchange (ETDEWEB)

    Prelovsek, S.; Orginos, K

    2003-05-01

    We study the q-barq singlet and non-singlet scalar-meson masses using domain wall fermions and the quenched approximation. The singlet mass is found to be smaller than the non-singlet mass and indicates that the lowest singlet meson state could be lighter than 1 GeV. The two-point functions for very small quark masses are compared with expectations from the small-volume chiral perturbation theory and the presence of fermionic zero modes.

  14. Localization of bulk form fields on dilatonic domain walls

    International Nuclear Information System (INIS)

    Youm, Donam

    2001-06-01

    We study the localization properties of bulk form potentials on dilatonic domain walls. We find that bulk form potentials of any ranks can be localized as form potentials of the same ranks or one lower ranks, for any values of the dilaton coupling parameter. For large enough values of the dilaton coupling parameter, bulk form potentials of any ranks can be localized as form potentials of both the same ranks and one lower ranks. (author)

  15. Aichelburg-Sexl boost of domain walls and cosmic strings

    International Nuclear Information System (INIS)

    Barrabes, C.; Hogan, P.A.; Israel, W.

    2002-01-01

    We consider the application of the Aichelburg-Sexl boost to plane and line distributions of matter. Our analysis shows that for a domain wall the space-time after the boost is flat except on a null hypersurface which is the history of a null shell. For a cosmic string we study the influence of the boost on the conical singularity and give the new value of the conical deficit

  16. Topological Valley Transport at Bilayer Graphene Domain Walls

    Science.gov (United States)

    2015-04-22

    resistances are lower than that expected from the semiconductor bandgap in ideal bilayer graphene , presumably owing to impurities and defects in our devices...LETTER doi:10.1038/nature14364 Topological valley transport at bilayer graphene domain walls Long Ju1*, Zhiwen Shi1*, Nityan Nair1, Yinchuan Lv1...Electron valley, a degree of freedom that is analogous to spin, can lead to novel topological phases in bilayer graphene . A tunable bandgap can be

  17. Domain Walls in Helical Magnets: Elasticity and Pinning

    OpenAIRE

    Nattermann, Thomas

    2012-01-01

    Recently completely new types of domain walls (DWs) have been discovered in helical magnets, consisting generically of a regular array of {\\it pairs} of magnetic vortex lines \\cite{Li+12}. Only for special orientations DWs are free of vortices. In this article we calculate their elastic and pinning properties, using the pitch angle $\\theta$ as a small parameter. In particular we show that vortex free DWs exhibit long range elasticity which makes them very stiff and suppresses their pinning by...

  18. Domain Walls, Black Holes and Supersymmetric Quantum Mechanics.

    Energy Technology Data Exchange (ETDEWEB)

    Shmakova, Marina

    2001-07-25

    Supersymmetric solutions, such as BPS domain walls or black holes, in four- and five-dimensional supergravity theories with eight supercharges can be described by effective quantum mechanics with a potential term. We show how properties of the latter theory can help us to learn about the physics of supersymmetric vacua and BPS solutions in these supergravity theories. The general approach is illustrated in a number of specific examples where scalar fields of matter multiplets take values in symmetric coset spaces.

  19. Segmental front line dynamics of randomly pinned ferroelastic domain walls

    Science.gov (United States)

    Puchberger, S.; Soprunyuk, V.; Schranz, W.; Carpenter, M. A.

    2018-01-01

    Dynamic mechanical analysis (DMA) measurements as a function of temperature, frequency, and dynamic force amplitude are used to perform a detailed study of the domain wall motion in LaAlO3. In previous DMA measurements Harrison et al. [Phys. Rev. B 69, 144101 (2004), 10.1103/PhysRevB.69.144101] found evidence for dynamic phase transitions of ferroelastic domain walls in LaAlO3. In the present work we focus on the creep-to-relaxation region of domain wall motion using two complementary methods. We determine, in addition to dynamic susceptibility data, waiting time distributions of strain jerks during slowly increasing stress. These strain jerks, which result from self-similar avalanches close to the depinning threshold, follow a power-law behavior with an energy exponent ɛ =1.7 ±0.1 . Also, the distribution of waiting times between events follows a power law N (tw) ∝tw-(n +1 ) with an exponent n =0.9 , which transforms to a power law of susceptibility S (ω ) ∝ω-n . The present dynamic susceptibility data can be well fitted with a power law, with the same exponent (n =0.9 ) up to a characteristic frequency ω ≈ω* , where a crossover from stochastic DW motion to the pinned regime is well described using the scaling function of Fedorenko et al. [Phys. Rev. B 70, 224104 (2004), 10.1103/PhysRevB.70.224104].

  20. Joule heating and current-induced domain wall motion

    Science.gov (United States)

    Curiale, J.; Lemaître, A.; Niazi, T.; Faini, G.; Jeudy, V.

    2012-11-01

    We investigate numerically and experimentally the Joule heating produced by current pulses and its contribution to current-induced domain wall (DW) motion in a (Ga,Mn)As ferromagnetic semiconductor. Different thermal coupling between tracks and substrates are explored. A direct contact leads to a logarithmic transient temperature rise and a stationary state determined by the substrate thickness. The introduction of a low thermal conducting (Ga,In)As interlayer produces an additional temperature rise whose time variation and magnitude are analyzed. Experimentally, the measured temperature rises present a good agreement with predictions over more than four orders of magnitude in time for values of the heat conductivity and of the heat capacity close to those reported in the literature. The Joule heating is shown to produce non-linearities in the domain wall velocity versus current density characteristics. A correction of Joule heating is proposed and permits the identification of the flow regimes from a comparison of domain-wall dynamics in tracks presenting different pinning characteristics.

  1. Annihilation of Domain Walls in a Ferromagnetic Wire

    Science.gov (United States)

    Ghosh, Anirban; Huang, Kevin; Tchernyshyov, Oleg

    We study the annihilation of topological solitons in one of the simplest systems that support them: a one-dimensional ferromagnetic wire with an easy axis along its length. In the presence of energy dissipation due to viscous losses, two solitons (domain walls) on the wire, when released from afar, approach each other and eventually annihilate to create a uniformly magnetized state. Starting from a class of exact solutions for stationary two-domain-wall configurations in the absence of dissipation, we develop an effective theory that describes this annihilation in terms of four collective coordinates: a) the two zero modes corresponding to the location of the center and the average azimuthal angle of the full structure and b) their two conjugate momenta which describe the relative twist and the relative separation of the two domain walls respectively. Comparison with micromagnetic simulation on OOOMF confirms that this theory captures well the essential physics of the process. We believe this work will be a good starting point for studying the annihilation of more complicated topological solitons like vortices and skyrmions in ferromagnetic thin films. This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-FG02-08ER46544.

  2. Domain wall propagation tuning in magnetic nanowires through geometric modulation

    Energy Technology Data Exchange (ETDEWEB)

    Arzuza, L.C.C., E-mail: luisarzuza179@gmail.com [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas (SP) (Brazil); Universidad de la Costa, Departamento de Ciencias Naturales y Exactas, Calle 58 No. 55-66, Barranquilla (Colombia); López-Ruiz, R. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas (SP) (Brazil); Salazar-Aravena, D. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas (SP) (Brazil); Departamento de Física, Facultad de Ciencias, Universidad de Tarapacá, 1000007 Arica (Chile); Knobel, M. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas (SP) (Brazil); Brazilian Nanotechnology National Laboratory, Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), 13083-970 Campinas (SP) (Brazil); Béron, F.; Pirota, K.R. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas (SP) (Brazil)

    2017-06-15

    Highlights: • The modulated nanowires dynamics occurs through two reversal modes. • Modulated nanowires show a change in the χ in contrast to homogeneous ones. • The FORC method reveals a non-uniform stray field due to shape modulation. - Abstract: The magnetic behavior of nickel modulated nanowires embedded in porous alumina membranes is investigated. Their diameters exhibit a sharp transition between below (35 nm) and above (52 nm) the theoretical limit for transverse and vortex domain walls. Magnetic hysteresis loops and first-order reversal curves (FORCs) were measured on several ordered nanowire arrays with different wide-narrow segment lengths ratio and compared with those from homogenous nanowires. The experimental magnetic response evidences a rather complex susceptibility behavior for nanowires with modulated diameter. Micromagnetic simulations on isolated and first-neighbors arrays of nanowires show that the domain wall structure, which depends on the segment diameter, suffers a transformation while crossing the diameter modulation, but without any pinning. The experimental array magnetic behavior can be ascribed to a heterogeneous stray field induced by the diameter modulation, yielding a stronger interaction field at the wide extremity than at the narrow one. The results evidence the possibility to control the domain wall propagation and morphology by modulating the lateral aspect of the magnetic entity.

  3. Magnetic domain wall engineering in a nanoscale permalloy junction

    Science.gov (United States)

    Wang, Junlin; Zhang, Xichao; Lu, Xianyang; Zhang, Jason; Yan, Yu; Ling, Hua; Wu, Jing; Zhou, Yan; Xu, Yongbing

    2017-08-01

    Nanoscale magnetic junctions provide a useful approach to act as building blocks for magnetoresistive random access memories (MRAM), where one of the key issues is to control the magnetic domain configuration. Here, we study the domain structure and the magnetic switching in the Permalloy (Fe20Ni80) nanoscale magnetic junctions with different thicknesses by using micromagnetic simulations. It is found that both the 90-° and 45-° domain walls can be formed between the junctions and the wire arms depending on the thickness of the device. The magnetic switching fields show distinct thickness dependencies with a broad peak varying from 7 nm to 22 nm depending on the junction sizes, and the large magnetic switching fields favor the stability of the MRAM operation.

  4. The effect of magnetic domain walls on the complex permeability of bulk Z-type cobalt hexaferrite along both W and Y-phases

    Energy Technology Data Exchange (ETDEWEB)

    Daró, Fábio R., E-mail: vonrho.colaborador@ieav.cta.br [Post Graduate Program, Aeronautics Institute of Technology (ITA), Praça Marechal Eduardo Gomes, 50, CEP 12228-900, São José Dos Campos, SP (Brazil); Migliano, Antonio Carlos C. [Applied Physics Division (EFA), Institute for Advanced Studies (IEAv), Trevo Coronel Aviador José Alberto Albano do Amarante, 1, CEP 12228-001, São José Dos Campos, SP (Brazil); Zanella, Glauco P.; Hirata, Anderson K. [Post Graduate Program, Aeronautics Institute of Technology (ITA), Praça Marechal Eduardo Gomes, 50, CEP 12228-900, São José Dos Campos, SP (Brazil); De Polli, Yasmara C. [Applied Physics Division (EFA), Institute for Advanced Studies (IEAv), Trevo Coronel Aviador José Alberto Albano do Amarante, 1, CEP 12228-001, São José Dos Campos, SP (Brazil); Salvadori, Maria Cecília B. [Thin Films Laboratory (LFF), Institute of Physics (IFUSP), University of São Paulo - USP, Rua do Matão, Travessa R, 187, CEP 05508-090, São Paulo, SP (Brazil)

    2016-02-15

    We analyzed a bulk cobalt hexaferrite sample set with the same powder composition obtained by the solid–state reaction method, and made of the W, Y and Z-phases. Transmission/reflection method (TR) measurements of the complex impedance both in radio frequency (RF) and microwave (MW) spectra, as well as reflectance (RL) exhibited high absorption and small losses, still appearing similar to the pattern that is exhibited by the Z-type, even though the largest amount of W-phase. Magnetic force microscopy (MFM), in turn, revealed the existence of narrow magnetic domains consisting of 300–500 nm wide parallel stripes on the crystal basal plane and down to 100 nm wide parallel stripes aligned in parallel to stacked crystal layers that would not be easily perceived by other methods. These domains may contribute to the exhibited complex permeability, since in ferrite both domain wall resonance (DWR) and domain – or spin rotation – resonance (DR) are inversely proportional to the square root of domain width. Nevertheless, we concluded that several flux-pinning defects and impeding factors of the polycrystalline setup, such as charge carriers shown by TR, are probably more important than anisotropy isolated to determine domain setup, and how this acts on the complex magnetic permeability. - Highlights: • MFM detected small magnetic domains not easily perceived by other methods. • High ferromagnetic resonances are favored by narrow magnetic domains. • Electron hopping improves permittivity but is undesirable for permeability.

  5. Example of a self-consistent solution for a fermion on domain wall

    International Nuclear Information System (INIS)

    Gani, V. A.; Ksenzov, V. G.; Kudryavtsev, A. E.

    2010-01-01

    A self-consistent solution for a fermion coupled to static scalar field in the form of a kink (domain wall) is discussed. In particular, the case when the fermion occupies an excited nonzero frequency level in the presence of the domain-wall field is studied. The effect of the domain-wall profile distortion is calculated analytically.

  6. Piercing of domain walls: new mechanism of gravitational radiation

    Science.gov (United States)

    Gal'tsov, Dmitri; Melkumova, Elena; Spirin, Pavel

    2018-01-01

    Domain wall (DW) moving in media undergoes the friction force due to particle scattering. However certain particles are not scattered, but perforate the wall. As a result, the wall gets excited in the form of the branon wave, while the particle experiences an acceleration jump. This gives rise to generation of gravitational waves which we call "piercing gravitational radiation" (PGR). Though this effect is of higher order in the gravitational constant than the quadrupole radiation from the collapsing DWs, its amplitude is enhanced in the case of relativistic particles or photons because of absence of the velocity factor which is present in the quadrupole formula. We derive the spectral-angular distribution of PGR within the simplified model of the weakly gravitating particle-wall system in Minkowski space-time of arbitrary dimensions. Within this model the radiation amplitude is obtained analytically. The spectral-angular distribution of PGR in such an approach suffers from infrared and ultraviolet divergences as well as from collinear divergence in the case of a massless perforating particle. Different cut-off schemes appropriate in various dimensions are discussed. Our results are applicable both to cosmological DWs and to the braneworld models. PGR can be relevant in the infrared part of the spectrum of the relic gravitons where radiation from the collapsed DWs is damped.

  7. Higher dimensional curved domain walls on Kähler surfaces

    International Nuclear Information System (INIS)

    Akbar, Fiki T.; Gunara, Bobby E.; Radjabaycolle, Flinn C.; Wijaya, Rio N.

    2017-01-01

    In this paper we study some aspects of curved BPS-like domain walls in higher dimensional gravity theory coupled to scalars where the scalars span a complex Kähler surface with scalar potential turned on. Assuming that a fake superpotential has a special form which depends on Kähler potential and a holomorphic function, we prove that BPS-like equations have a local unique solution. Then, we analyze the vacuum structure of the theory including their stability using dynamical system and their existence in ultraviolet-infrared regions using renormalization group flow.

  8. High temperature meson propagators with domain-wall quarks

    International Nuclear Information System (INIS)

    Lagae, J.-F.; Sinclair, D. K.

    1999-01-01

    We study the chiral properties of domain-wall quarks at high temperatures on an ensemble of quenched configurations. Low lying eigenmodes of the Dirac operator are calculated and used to check the extent to which the Atiyah-Singer index theorem is obeyed on lattices with finite N 5 . We calculate the connected and disconnected screening propagators for the lowest mass scalar and pseudoscalar mesons in the sectors of different topological charge and note that they behave as expected. Separating out the would-be zero eigenmodes enables us to accurately estimate the disconnected propagators with far less effort than would be needed otherwise

  9. Higher dimensional curved domain walls on Kähler surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Akbar, Fiki T., E-mail: ftakbar@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Gunara, Bobby E., E-mail: bobby@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Radjabaycolle, Flinn C. [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Departement of Physics, Faculty of Mathematics and Natural Sciences, Cendrawasih University, Jl. Kampwolker Kampus Uncen Baru Waena-Jayapura 99351 (Indonesia); Wijaya, Rio N. [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia)

    2017-03-15

    In this paper we study some aspects of curved BPS-like domain walls in higher dimensional gravity theory coupled to scalars where the scalars span a complex Kähler surface with scalar potential turned on. Assuming that a fake superpotential has a special form which depends on Kähler potential and a holomorphic function, we prove that BPS-like equations have a local unique solution. Then, we analyze the vacuum structure of the theory including their stability using dynamical system and their existence in ultraviolet-infrared regions using renormalization group flow.

  10. Domain walls in (Ga,Mn)As diluted magnetic semiconductor

    Czech Academy of Sciences Publication Activity Database

    Sugawara, A.; Kasai, H.; Tonomura, A.; Brown, P.D.; Campion, R. P.; Edmonds, K. W.; Gallagher, B. L.; Zemen, Jan; Jungwirth, Tomáš

    2008-01-01

    Roč. 100, č. 4 (2008), 047202/1-047202/4 ISSN 0031-9007 R&D Projects: GA MŠk LC510; GA ČR GEFON/06/E002; GA ČR GA202/05/0575; GA ČR GA202/04/1519 EU Projects: European Commission(XE) 015728 - NANOSPIN Institutional research plan: CEZ:AV0Z10100521 Keywords : dilute ferromagnetic semiconductor * Néel domain walls * electron holography * Landau-Lifshitz-Gilbert simulation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.180, year: 2008

  11. Observation of injection and pinning of domain walls in magneticnanowires using photoemission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Luc; Rettner, Charles; Hayashi, Masamitsu; Samant, MaheshG.; Parkin Stuart S.P.; Doran, Andrew; Scholl, Andreas

    2005-12-19

    Photoemission electron microscopy is used to explore the injection and pinning of magnetic domain walls in 250-nm-wide, 20-nm-thick Permalloy nanowires. Domain walls are injected from a micron-sized elliptical nucleation pad at one end of the nanowire. A vortex-like structure is readily nucleated in this pad at low magnetic fields 15 Oe, whereas injection of a domain wall into the nanowire requires significantly larger fields 60 Oe. Domain walls are pinned in the nanowire at notches patterned along the wires edges. The domain walls are observed to have vortex-like structures with chiralities that vary in successive experiments.

  12. Observation of injection and pinning of domain walls in magnetic nanowires using photoemission electron microscopy

    Science.gov (United States)

    Thomas, Luc; Rettner, Charles; Hayashi, Masamitsu; Samant, Mahesh G.; Parkin, Stuart S. P.; Doran, Andrew; Scholl, Andreas

    2005-12-01

    Photoemission electron microscopy is used to explore the injection and pinning of magnetic domain walls in 250-nm-wide, 20-nm-thick Permalloy nanowires. Domain walls are injected from a micron-sized elliptical nucleation pad at one end of the nanowire. A vortex-like structure is readily nucleated in this pad at low magnetic fields (<15Oe), whereas injection of a domain wall into the nanowire requires significantly larger fields (˜60Oe). Domain walls are pinned in the nanowire at notches patterned along the wire's edges. The domain walls are observed to have vortex-like structures with chiralities that vary in successive experiments.

  13. Interactions with the actin cytoskeleton are required for cell wall localization of barley stripe mosaic virus TGB proteins

    Science.gov (United States)

    The host cytoskeleton and membrane system are the main routes by which plant viruses move within or between cells. Barley stripe mosaic virus (BSMV) -induced actin filament thickening was visualized in the cytoskeleton of agroinfiltrated Nicotiana benthamiana epidermal cells expressing DsRed:Talin. ...

  14. Localized fermions on domain walls and extended supersymmetric quantum mechanics

    International Nuclear Information System (INIS)

    Oikonomou, V K

    2014-01-01

    We study fermionic fields localized on topologically unstable domain walls bounded by strings in a grand unified theory theoretical framework. Particularly, we found that the localized fermionic degrees of freedom, which are up and down-quarks as well as charged leptons, are connected to three independent N = 2, d = 1 supersymmetric quantum mechanics algebras. As we demonstrate, these algebras can be combined to form higher order representations of N = 2, d = 1 supersymmetry. Due to the uniform coupling of the domain wall solutions to the down-quarks and leptons, we also show that a higher order N = 2, d = 1 representation of the down-quark–lepton system is invariant under a duality transformation between the couplings. In addition, the two N = 2, d = 1 supersymmetries of the down-quark–lepton system, combine at the coupling unification scale to form an N = 4, d = 1 supersymmetry. Furthermore, we present the various extra geometric and algebraic attributes that the fermionic systems acquire, owing to the underlying N = 2, d = 1 algebras. (paper)

  15. The profile of the domain walls in amorphous glass-covered microwires

    Energy Technology Data Exchange (ETDEWEB)

    Beck, F.; Rigue, J.N. [Universidade Federal de Santa Maria, Campus Cachoeira do Sul, RS (Brazil); Carara, M., E-mail: carara@smail.ufsm.br [Departamento de Física, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil)

    2017-08-01

    Highlights: • Glass-covered microwires with positive magnetostriction were studied. • The single domain wall dynamics was studied under different conditions. • We have evaluated the profile and shape of the moving domain walls. • The domain wall evolves from a bell shape to a parabolic one when a current is applied. - Abstract: We have studied the domain wall dynamics in Joule-annealed amorphous glass-covered microwires with positive magnetostriction in the presence of an electric current, in order to evaluate the profile and shape of the moving domain wall. Such microwires are known to present magnetic bi-stability when axially magnetized. The single domain wall dynamics was evaluated under different conditions, under an axially applied stress and an electric current. We have observed the well known increasing of the domain wall damping with the applied stress due to the increase in the magnetoelastic anisotropy and, when the current is applied, depending on the current intensity and direction, a modification on the axial domain wall damping. When the orthogonal motion of the domain wall is considered, we have observed that the associated velocity present a smaller dependence on the applied current intensity. It was observed a modification on both the domain wall shape and length. In a general way, the domain wall evolves from a bell shape to a parabolic shape as the current intensity is increased. The results were explained in terms of the change in the magnetic energy promoted by the additional Oersted field.

  16. Study of domain wall propagation in nanostructured CoPt multilayers by using antisymmetric magnetoresistance

    International Nuclear Information System (INIS)

    Rodriguez-Rodriguez, G; Perez-Junquera, A; Hierro-Rodriguez, A; Montenegro, N; Alameda, J M; Velez, M; Menendez, J L; Ravelosona, D

    2010-01-01

    Domain wall propagation has been studied in perpendicular anisotropy CoPt multilayers patterned by e-beam lithography into 5 μm wide wires. Positive and negative peaks appear in time resolved magnetoresistance curves, associated to the different directions of domain wall propagation along the wires. The field dependence of domain wall velocity is well described by a creep model of a 1D wall in the presence of weak disorder with critical exponent μ=1/4.

  17. Domains within domains and walls within walls: Evidence for polar domains in cryogenic SrTiO.sub.3./sub..

    Czech Academy of Sciences Publication Activity Database

    Salje, E.K.H.; Aktas, O.; Carpenter, M.A.; Laguta, Valentyn; Scott, J.F.

    2013-01-01

    Roč. 111, č. 24 (2013), "247603-1"-"247603-5" ISSN 0031-9007 Institutional support: RVO:68378271 Keywords : ferroelectric domains * SrTiO 3 * phase transition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.728, year: 2013

  18. Unfolding of Vortices into Topological Stripes in a Multiferroic Material

    Science.gov (United States)

    Wang, X.; Mostovoy, M.; Han, M. G.; Horibe, Y.; Aoki, T.; Zhu, Y.; Cheong, S.-W.

    2014-06-01

    Multiferroic hexagonal RMnO3 (R =rare earths) crystals exhibit dense networks of vortex lines at which six domain walls merge. While the domain walls can be readily moved with an applied electric field, the vortex cores so far have been impossible to control. Our experiments demonstrate that shear strain induces a Magnus-type force pulling vortices and antivortices in opposite directions and unfolding them into a topological stripe domain state. We discuss the analogy between this effect and the current-driven dynamics of vortices in superconductors and superfluids.

  19. Far- and near-field second-harmonic imaging of ferroelectric domain walls

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Pedersen, K.; Skettrup, Torben

    1998-01-01

    Domain walls in periodically poled ferroelectric LiNbO3 crystals are observed with both far- and near-field imaging techniques that make use of second harmonic generation in the transition regions between neighbouring domains. Second harmonic images of domain walls represent bright lines of about 0.......5 micrometers in width (as measured with the near-field microscope) for the polarization of the second harmonic radiation perpendicular to the domain walls. Origin and selection rules for the constrast in second harmonic images of domain walls are discussed....

  20. Nanoscale thermoelectrical detection of magnetic domain wall propagation

    Science.gov (United States)

    Krzysteczko, Patryk; Wells, James; Fernández Scarioni, Alexander; Soban, Zbynek; Janda, Tomas; Hu, Xiukun; Saidl, Vit; Campion, Richard P.; Mansell, Rhodri; Lee, Ji-Hyun; Cowburn, Russell P.; Nemec, Petr; Kazakova, Olga; Wunderlich, Joerg; Schumacher, Hans Werner

    2017-06-01

    In magnetic nanowires with perpendicular magnetic anisotropy (PMA) magnetic domain walls (DWs) are narrow and can move rapidly driven by current induced torques. This enables important applications like high-density memories for which the precise detection of the position and motion of a propagating DW is of utmost interest. Today's DW detection tools are often limited in resolution, require complex instrumentation, or can only be applied on specific materials. Here we show that the anomalous Nernst effect provides a simple and powerful tool to precisely track the position and motion of a single DW propagating in a PMA nanowire. We detect field and current driven DW propagation in both metallic heterostructures and dilute magnetic semiconductors over a broad temperature range. The demonstrated spatial accuracy below 20 nm is comparable to the DW width in typical metallic PMA systems.

  1. Anomalous Hall-like effect probe of antiferromagnetic domain wall.

    Science.gov (United States)

    Lang, Lili; Qiu, Xuepeng; Zhou, Shiming

    2018-01-10

    Of crucial importance to antiferromagnetic (AF) spintronic devices, AF domain wall (AFDW), created in exchange biased Y 3 Fe 5 O 12 /Ni 0.50 Co 0.50 O (NiCoO)/Pt, is characterized by anomalous Hall-like effect through magnetic proximity effect and spin Hall magnetoresistance at NiCoO/Pt interface. The AFDW thickness, in the order of nanometers, has been for the first time proved in experiments to increase with increasing temperature. AF spins within AFDW show the same chirality in decent and ascent branches of ferromagnetic magnetization reversal process. Moreover, the uncompensated magnetic moment at the NiCoO/Pt interface is of perpendicular magnetization anisotropy and changes linearly in magnitude with temperature due to the reduced coordination of the magnetic atoms on the AF surface. This work will help to clarify the mechanism of the spin current propagation in AF materials and fully understand the physics behind exchange bias.

  2. Instability of Walker propagating domain wall in magnetic nanowires.

    Science.gov (United States)

    Hu, B; Wang, X R

    2013-07-12

    The stability of the well-known Walker propagating domain wall (DW) solution of the Landau-Lifshitz-Gilbert equation is analytically investigated. Surprisingly, a propagating DW is always dressed with spin waves so that the Walker rigid-body propagating DW mode does not occur in reality. In the low field region only stern spin waves are emitted while both stern and bow waves are generated under high fields. In a high enough field, but below the Walker breakdown field, the Walker solution could be convective or absolute unstable if the transverse magnetic anisotropy is larger than a critical value, corresponding to a significant modification of the DW profile and DW propagating speed.

  3. Vortices and domain walls: 'Wormholes' in unconventional superconductors

    International Nuclear Information System (INIS)

    Bessarab, P F; Radievsky, A V

    2010-01-01

    In the framework of the 2D and 3D time-dependent Ginzburg-Landau model we study superconductors with multicomponent order parameter (d-pairing). We argue that topological defects inside the sample do affect its thermodynamic properties such as hysteresis loop, susceptibility, etc. Along with earlier known topological defects such as Abrikosov vortices, domain walls (DWs) which separate different magnetic phases and even vortices inside the DW, we found an interesting combination of DWs and vortices. Namely we show that equivalent magnetic phases may be linked together with a vortex going through the other magnetic phase. This configuration may correspond to a stable state even in a zero external magnetic field. We also mention that this configuration is topologically similar to the 'wormholes' in the quantum gravity.

  4. Kaon B-parameter from quenched domain-wall QCD

    International Nuclear Information System (INIS)

    Ali Khan, A.; Aoki, S.; Aoki, Y.; Burkhalter, R.; Ejiri, S.; Fukugita, M.; Hashimoto, S.; Ishizuka, N.; Iwasaki, Y.; Izubuchi, T.; Kanaya, K.; Kaneko, T.; Kuramashi, Y.; Nagai, K.-I.; Noaki, J.; Okawa, M.; Shanahan, H.P.; Taniguchi, Y.; Ukawa, A.; Yoshie, T.

    2001-01-01

    We report on a calculation of B K with domain wall fermion action in quenched QCD. Simulations are made with a renormalization group improved gauge action at β = 2.6 and 2.9 corresponding to a -1 ∼ 2GeV and 3GeV. Effects due to finite fifth dimensional size N 5 and finite spatial size N σ are examined in detail. Matching to the continuum operator is made perturbatively at one loop order. We obtain B K (μ = 2GeV) 0.5746(61), where the error is statistical only, as an estimate of the continuum value in the MS-bar scheme with naive dimensional regularization. This value is smaller but consistent with B K (μ = 2GeV) = 0.628(42) obtained by the JLQCD Collaboration using the Kogut-Susskind quark action. Results for strange quark mass are also reported

  5. Graphene Exfoliation at a Ferroelectric Domain Wall Induced by the Piezoelectric Effect: Impact on the Conductance of the Graphene Channel

    Science.gov (United States)

    Morozovska, Anna N.; Kurchak, Anatolii I.; Strikha, Maksym V.

    2017-11-01

    p -n junctions in graphene on ferroelectric substrates have been actively studied, but the impact of the piezoelectric effect in ferroelectric substrate with ferroelectric domain walls (FDWs) on graphene characteristics was not considered. Because of the piezoeffect, ferroelectric domain stripes with opposite spontaneous polarizations elongate or contract depending on the polarity of voltage applied to the substrate. We show that the alternating piezoelectric displacement of the ferroelectric domain surfaces can lead to the alternate stretching and separation of graphene areas at the steps between elongated and contracted domains. Graphene separation at FDWs induced by the piezoeffect can cause unusual effects. In particular, the conductance of the graphene channel in a field-effect transistor increases significantly because electrons in the stretched section scatter on acoustic phonons. At the same time, the graphene conductance is determined by ferroelectric spontaneous polarization and varies greatly in the presence of FDWs. The revealed piezomechanism of graphene conductance control is promising for next generations of graphene-based field-effect transistors, modulators, electrical transducers, and piezoresistive elements. Also, our results propose the method of suspended graphene fabrication based on the piezoeffect in a ferroelectric substrate that does not require any additional technological procedures.

  6. Domain walls in thermal gauge field theories - myth or reality?

    Energy Technology Data Exchange (ETDEWEB)

    Smilga, A.V. [Bern Univ. (Switzerland). Inst. fuer Theoretische Physik]|[Gosudarstvennyj Komitet po Ispol`zovaniyu Atomnoj Ehnergii SSSR, Moscow (Russian Federation). Inst. Teoreticheskoj i Ehksperimental`noj Fiziki

    1994-01-01

    We argue different Z{sub N} thermal vacua of hot pure Yang-Mills theory distinguished in the standard approach by different values of Polyakov loop average

    {sub T} corresponds actually to one and the same physical state. A critical discussion of the argument which are usually put forward in favor of the opposite conclusion (that, in pure continuum Yang-Mills theory, distinct Z{sub N}-phases may coexist in the physical space being separated by the domain walls finite surface energy) is given. In particular, we note that the same arguments can be applied with an equal ease to Abelian theories and would lead to the existence of the walls in the high-T 4-dim QED and to appearance of the queer high-T solitons with the mass {approx} T{sup 2}/e in the Schwinger model. We emphasize that these configurations may be relevant for the Euclidean path integral but whether they correspond to Minkowski space objects is unclear. (author). 16 refs, 2 figs.

  7. Tuning the magnetic properties of stripe domain structured CoFeB films using stack structure with spacer layer thickness dependent interlayer coupling

    Science.gov (United States)

    Das, Camelia; Alagarsamy, Perumal

    2018-02-01

    We report a novel approach for tuning the magnetic properties of stripe domain structured amorphous Co40Fe40B20 (CoFeB) films by using stack structured [CoFeB (100 nm)/Ta (z = 0-1.5 nm)]n= 0-4/CoFeB (100 nm) films with spacer layer thickness dependent interlayer coupling. All the as-deposited films deposited directly on thermally oxidized Si substrate at ambient temperature exhibit amorphous structure. Single-layer CoFeB (x = 100-300 nm) films display transcritical loops with high coercivity (HC > 4 kA/m) and large applied field required for magnetization saturation (HS > 40 kA/m) due to the formation of magnetic stripe domains induced by the stress quenched in during the preparation of the films at a high deposition rate to form amorphous structure. With increasing n, the number of CoFeB layers in stack structure increases providing an enhanced interlayer coupling and a better flux closure, which leads to a substantial drop in HC (∼1.8 kA/m) and changes the loop shape away from transcritical into soft magnetic type with reduced HS (∼10 kA/m) and increased remanence ratio (>75%). However, the improvement in magnetic properties strongly depends on the values of n and z. Temperature dependent M-H loops reveal a competition between interlayer coupling and interfacial strain, which provides unusual variation of HC(T), i.e., minimum in HC(T) vs T curve, depending on z and n. The observed results are explained on the basis of stress dependent stripe domains in single layer films and number of CoFeB layers and spacer layer thickness dependent interlayer coupling in stack structured films. It is revealed that the fabrication of stack of thick CoFeB films having stripe domains and separated by optimum z is an alternative approach to improve the magnetic properties of thick CoFeB films.

  8. Micromagnetic analysis of current-induced domain wall motion in a bilayer nanowire with synthetic antiferromagnetic coupling

    Energy Technology Data Exchange (ETDEWEB)

    Komine, Takashi, E-mail: komine@mx.ibaraki.ac.jp; Aono, Tomosuke [Faculty of Engineering, Ibaraki University 4-12-1, Nakanarusawa, Hitachi, Ibaraki, 316-8511 (Japan)

    2016-05-15

    We demonstrate current-induced domain wall motion in bilayer nanowire with synthetic antiferromagnetic (SAF) coupling by modeling two body problems for motion equations of domain wall. The influence of interlayer exchange coupling and magnetostatic interactions on current-induced domain wall motion in SAF nanowires was also investigated. By assuming the rigid wall model for translational motion, the interlayer exchange coupling and the magnetostatic interaction between walls and domains in SAF nanowires enhances domain wall speed without any spin-orbit-torque. The enhancement of domain wall speed was discussed by energy distribution as a function of wall angle configuration in bilayer nanowires.

  9. Domain walls collision in Fe-rich and Co-rich glass covered microwires

    Directory of Open Access Journals (Sweden)

    Gonzalez J.

    2013-01-01

    Full Text Available We report the results of the investigation of domain walls propagation in Fe-rich and Co-rich microwires performed using Sixtus-Tonks and magneto-optical Kerr effect techniques. It was found that under certain experimental conditions we are able to create the regime of the motion of two domain walls moving to opposite directions which terminates by the collision of the domain walls. Also the domain walls collision was visualized using magneto-optical Kerr effect microscope when the surface giant Barkhausen jump induced by circular magnetic field has been observed.

  10. The Effect of a Pulsed Magnetic Field on Domain Wall Resistance in Magnetic Nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Majidi, R; Tehranchi, M M; Tabrizi, K Ghafoori [Department of Physics, G.C., Shahid Beheshti University, Evin, 19838-63113, Tehran (Iran, Islamic Republic of); Phirouznia, A, E-mail: Teranchi@cc.sbu.ac.ir [Department of Physics, Azarbaijan University of Tarbiat Moallem, 53714-161 Tabriz (Iran, Islamic Republic of)

    2011-04-01

    The effect of a pulsed magnetic field on domain wall magnetoresistance for an ideal one-dimensional magnetic nanowire with a domain wall has been investigated. The analysis has been based on the Boltzmann transport equation, within the relaxation time approximation. The results indicate that the domain wall resistance increase when enhancing the magnetic field. The evaluation of local magnetization has been considered in the presence of a pulsed magnetic field. The time evaluation of the magnetization also has an effect on the domain wall resistance. The resistance depends on the contribution of the Zeeman and exchange interactions.

  11. Domain wall magnetoresistance in BiFeO3 thin films measured by scanning probe microscopy.

    Science.gov (United States)

    Domingo, N; Farokhipoor, S; Santiso, J; Noheda, B; Catalan, G

    2017-08-23

    We measure the magnetotransport properties of individual 71° domain walls in multiferroic BiFeO 3 by means of conductive-atomic force microscopy (C-AFM) in the presence of magnetic fields up to one Tesla. The results suggest anisotropic magnetoresistance at room temperature, with the sign of the magnetoresistance depending on the relative orientation between the magnetic field and the domain wall plane. A consequence of this finding is that macroscopically averaged magnetoresistance measurements for domain wall bunches are likely to underestimate the magnetoresistance of each individual domain wall.

  12. Time-resolved imaging of current-induced domain-wall oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Bocklage, Lars; Krueger, Benjamin; Eiselt, Rene; Bolte, Markus; Fischer, Peter; Meier, Guido

    2008-10-07

    Current-induced domain-wall dynamics is investigated via high-resolution soft x-ray transmission microscopy by a stroboscopic pump-and-probe measurement scheme at a temporal resolution of 200 ps. A 180{sup o} domain wall in a restoring potential of a permalloy microstructure is displaced from its equilibrium position by nanosecond current pulses leading to oscillations with velocities up to 325 m/s. The motion of the wall is described with an analytical model of a rigid domain wall in a nonharmonic potential allowing one to determine the mass of the domain wall. We show that Oersted fields dominate the domain-wall dynamics in our geometry.

  13. Modeling thermally activated domain wall dynamics in thin magnetic strips with disorder

    Energy Technology Data Exchange (ETDEWEB)

    Laurson, L; Mughal, A; Serpico, C; Durin, G; Zapperi, S, E-mail: lasse.laurson@gmail.com [ISI Foundation, Torino (Italy)

    2011-04-01

    We study the effect of disorder and temperature on the field-driven dynamics of a transverse domain wall occurring in thin and narrow magnetic strips made of a soft magnetic material such as permalloy. Motivated by a micromagnetic description of such a domain wall, we construct a model based on two coupled flexible lines enclosing the domain wall transition region, capturing both the finite width and the characteristic V-shape of the wall. Disorder is included via randomly distributed pinning centers interacting with the two lines. We study the field-driven dynamics of the domain wall in disordered strips in a finite temperature, and compare our findings to experimental observations of stochastic domain wall dynamics.

  14. SH3b Cell wall binding domains can enhance anti-staphylococcal activity of endolysin lytic domains.

    Science.gov (United States)

    Bacteriophage endolysins are peptidoglycan hydrolases and a potential new source of antimicrobials. A large subset of these proteins contain a C-terminal SH3b_5 cell wall binding domain that has been shown [for some] to be essential for accurate cell wall recognition and subsequent staphylolytic ac...

  15. Charm physics with physical light and strange quarks using domain wall fermions

    CERN Document Server

    Boyle, Peter A; Garron, Nicolas; Khamseh, Ava; Marinkovic, Marina; Sanfilippo, Francesco; Tsang, Justus Tobias; Boyle, Peter A.

    2015-01-01

    We present a study of charm physics using RBC/UKQCD 2+1 flavour physical point domain wall fermion ensembles for the light quarks as well as for the valence charm quark. After a brief motivation of domain wall fermions as a suitable heavy quark discretisation we will show first results for masses and matrix elements.

  16. Five Dimensional Domain Walls in a Scalar-Tensor Theory of Gravitation

    Science.gov (United States)

    Reddy, D. R. K.; Govinda Rao, P.; Naidu, R. L.

    2008-11-01

    Five dimensional Kaluza-Klein space-time is considered in the presence of thick domain walls in the framework of scalar-tensor theory of gravitation proposed by Saez and Ballester (Phys. Lett. A 113:467, [1986]). Exact cosmological model, which represents a stiff domain wall, is presented. Some physical and kinematical properties of the model are also discussed.

  17. Resonant amplification of magnetic domain-wall motion by a train of current pulses.

    Science.gov (United States)

    Thomas, Luc; Hayashi, Masamitsu; Jiang, Xin; Moriya, Rai; Rettner, Charles; Parkin, Stuart

    2007-03-16

    The current-induced motion of magnetic domain walls confined to nanostructures is of interest for applications in magnetoelectronic devices in which the domain wall serves as the logic gate or memory element. The injection of spin-polarized current below a threshold value through a domain wall confined to a pinning potential results in its precessional motion within the potential well. We show that by using a short train of current pulses, whose length and spacing are tuned to this precession frequency, the domain wall's oscillations can be resonantly amplified. This makes possible the motion of domain walls with much reduced currents, more than five times smaller than in the absence of resonant amplification.

  18. Inertial displacement of a domain wall excited by ultra-short circularly polarized laser pulses

    Science.gov (United States)

    Janda, T.; Roy, P. E.; Otxoa, R. M.; Šobáň, Z.; Ramsay, A.; Irvine, A. C.; Trojanek, F.; Surýnek, M.; Campion, R. P.; Gallagher, B. L.; Němec, P.; Jungwirth, T.; Wunderlich, J.

    2017-05-01

    Domain wall motion driven by ultra-short laser pulses is a pre-requisite for envisaged low-power spintronics combining storage of information in magnetoelectronic devices with high speed and long distance transmission of information encoded in circularly polarized light. Here we demonstrate the conversion of the circular polarization of incident femtosecond laser pulses into inertial displacement of a domain wall in a ferromagnetic semiconductor. In our study, we combine electrical measurements and magneto-optical imaging of the domain wall displacement with micromagnetic simulations. The optical spin-transfer torque acts over a picosecond recombination time of the spin-polarized photo-carriers that only leads to a deformation of the initial domain wall structure. We show that subsequent depinning and micrometre-distance displacement without an applied magnetic field or any other external stimuli can only occur due to the inertia of the domain wall.

  19. Modulated Magnetic Nanowires for Controlling Domain Wall Motion: Toward 3D Magnetic Memories

    KAUST Repository

    Ivanov, Yurii P.

    2016-05-03

    Cylindrical magnetic nanowires are attractive materials for next generation data storage devices owing to the theoretically achievable high domain wall velocity and their efficient fabrication in highly dense arrays. In order to obtain control over domain wall motion, reliable and well-defined pinning sites are required. Here, we show that modulated nanowires consisting of alternating nickel and cobalt sections facilitate efficient domain wall pinning at the interfaces of those sections. By combining electron holography with micromagnetic simulations, the pinning effect can be explained by the interaction of the stray fields generated at the interface and the domain wall. Utilizing a modified differential phase contrast imaging, we visualized the pinned domain wall with a high resolution, revealing its three-dimensional vortex structure with the previously predicted Bloch point at its center. These findings suggest the potential of modulated nanowires for the development of high-density, three-dimensional data storage devices. © 2016 American Chemical Society.

  20. Reply to "Domain-growth kinetics of systems with soft walls''

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Præstgaard, Eigil

    1988-01-01

    On the basis of computer-simulation results for three different models with soft domain walls it is argued that the zero-temperature domain-growth kinetics falls in a separate universality class characterized by a kinetic growth exponent n≃0.25. However, for finite temperatures there is a distinct...... crossover to Lifshitz-Allen-Cahn kinetics n=0.50, thus suggesting that the soft-wall and hard-wall universality classes become identical at finite temperatures....

  1. Domain wall pinning by magnetic inhomogeneities in Sm(CoNi) sub 2. 5

    Energy Technology Data Exchange (ETDEWEB)

    Chen, X.; Gaunt, P. (Department of Physics, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada (CA))

    1990-05-01

    Domain wall (thin 180{degree} wall) pinning by pinning sites of atomic size is studied by a new model which is based on the argument that the temperature dependence of the coercivity originates from both thermal activation of the domain wall and the temperature dependence of the height of the energy barriers. This model successfully describes the temperature dependence of the coercivity of a Sm(CoNi){sub 2.5} ferromagnet.

  2. Soft-wall domain-growth kinetics of twofold-degenerate ordering

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.

    1986-01-01

    The domain growth in a two-dimensional twofold-degenerate system with soft domain walls is shown to obey dynamical scaling. The value of the growth exponent is n≃0.25 which differs from the classical Lifshitz-Allen-Cahn prediction n=(1/2), but accords with recent findings for other growth models ...... with soft walls. The results suggest that domain-wall softness may be more important than the degeneracy of the ground state for a possible universal classification of domain-growth kinetics....

  3. Domain wall fermion QCD with the exact one flavor algorithm

    Science.gov (United States)

    Jung, C.; Kelly, C.; Mawhinney, R. D.; Murphy, D. J.

    2018-03-01

    Lattice QCD calculations including the effects of one or more nondegenerate sea quark flavors are conventionally performed using the rational hybrid Monte Carlo (RHMC) algorithm, which computes the square root of the determinant of D†D , where D is the Dirac operator. The special case of two degenerate quark flavors with the same mass is described directly by the determinant of D†D —in particular, no square root is necessary—enabling a variety of algorithmic developments, which have driven down the cost of simulating the light (up and down) quarks in the isospin-symmetric limit of equal masses. As a result, the relative cost of single quark flavors—such as the strange or charm—computed with RHMC has become more expensive. This problem is even more severe in the context of our measurements of the Δ I =1 /2 K →π π matrix elements on lattice ensembles with G -parity boundary conditions, since G -parity is associated with a doubling of the number of quark flavors described by D , and thus RHMC is needed for the isospin-symmetric light quarks as well. In this paper we report on our implementation of the exact one flavor algorithm (EOFA) introduced by the TWQCD Collaboration for simulations including single flavors of domain wall quarks. We have developed a new preconditioner for the EOFA Dirac equation, which both reduces the cost of solving the Dirac equation and allows us to reuse the bulk of our existing high-performance code. Coupling these improvements with careful tuning of our integrator, the time per accepted trajectory in the production of our 2 +1 flavor G -parity ensembles with physical pion and kaon masses has been decreased by a factor of 4.2.

  4. Temporary formation of highly conducting domain walls for non-destructive read-out of ferroelectric domain-wall resistance switching memories

    Science.gov (United States)

    Jiang, Jun; Bai, Zi Long; Chen, Zhi Hui; He, Long; Zhang, David Wei; Zhang, Qing Hua; Shi, Jin An; Park, Min Hyuk; Scott, James F.; Hwang, Cheol Seong; Jiang, An Quan

    2018-01-01

    Erasable conductive domain walls in insulating ferroelectric thin films can be used for non-destructive electrical read-out of the polarization states in ferroelectric memories. Still, the domain-wall currents extracted by these devices have not yet reached the intensity and stability required to drive read-out circuits operating at high speeds. This study demonstrated non-destructive read-out of digital data stored using specific domain-wall configurations in epitaxial BiFeO3 thin films formed in mesa-geometry structures. Partially switched domains, which enable the formation of conductive walls during the read operation, spontaneously retract when the read voltage is removed, reducing the accumulation of mobile defects at the domain walls and potentially improving the device stability. Three-terminal memory devices produced 14 nA read currents at an operating voltage of 5 V, and operated up to T = 85 °C. The gap length can also be smaller than the film thickness, allowing the realization of ferroelectric memories with device dimensions far below 100 nm.

  5. Domain wall conductivity in semiconducting hexagonal ferroelectric TbMnO3 thin films

    International Nuclear Information System (INIS)

    Kim, D J; Gruverman, A; Connell, J G; Seo, S S A

    2016-01-01

    Although enhanced conductivity of ferroelectric domain boundaries has been found in BiFeO 3 and Pb(Zr,Ti)O 3 films as well as hexagonal rare-earth manganite single crystals, the mechanism of the domain wall conductivity is still under debate. Using conductive atomic force microscopy, we observe enhanced conductance at the electrically-neutral domain walls in semiconducting hexagonal ferroelectric TbMnO 3 thin films where the structure and polarization direction are strongly constrained along the c-axis. This result indicates that domain wall conductivity in ferroelectric rare-earth manganites is not limited to charged domain walls. We show that the observed conductivity in the TbMnO 3 films is governed by a single conduction mechanism, namely, the back-to-back Schottky diodes tuned by the segregation of defects. (paper)

  6. Domain wall energy landscapes in amorphous magnetic films with asymmetric arrays of holes

    Energy Technology Data Exchange (ETDEWEB)

    Alija, A; Perez-Junquera, A; RodrIguez-RodrIguez, G; Velez, M; Alameda, J M; MartIn, J I [Depto. Fisica, Fac. Ciencias, Universidad de Oviedo - CINN, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Marconi, V I; Kolton, A B; Parrondo, J M R [Depto. Fisica Atomica, Molecular y Nuclear, and GISC, Universidad Complutense, 28040 Madrid (Spain); Anguita, J V [Instituto de Microelectronica de Madrid, CNM-CSIC, Isaac Newton 8, PTM, Tres Cantos, 28760 Madrid (Spain)

    2009-02-21

    Arrays of asymmetric holes have been defined in amorphous Co-Si films by e-beam lithography in order to study domain wall motion across the array subject to the asymmetric pinning potential created by the holes. Experimental results on Kerr effect magnetooptical measurements and hysteresis loops are compared with micromagnetic simulations in films with arrays of triangular holes. These show that the potential asymmetry favours forward wall propagation for flat walls but, if the wall contains a kink, net backward wall propagation is preferred at low fields, in agreement with minor loop experiments. The difference between the fields needed for forward and backward flat wall propagation increases as the size of the triangular holes is reduced, becoming maximum for 1 {mu}m triangles, which is the characteristic length scale set by domain wall width.

  7. Domain wall energy landscapes in amorphous magnetic films with asymmetric arrays of holes

    International Nuclear Information System (INIS)

    Alija, A; Perez-Junquera, A; RodrIguez-RodrIguez, G; Velez, M; Alameda, J M; MartIn, J I; Marconi, V I; Kolton, A B; Parrondo, J M R; Anguita, J V

    2009-01-01

    Arrays of asymmetric holes have been defined in amorphous Co-Si films by e-beam lithography in order to study domain wall motion across the array subject to the asymmetric pinning potential created by the holes. Experimental results on Kerr effect magnetooptical measurements and hysteresis loops are compared with micromagnetic simulations in films with arrays of triangular holes. These show that the potential asymmetry favours forward wall propagation for flat walls but, if the wall contains a kink, net backward wall propagation is preferred at low fields, in agreement with minor loop experiments. The difference between the fields needed for forward and backward flat wall propagation increases as the size of the triangular holes is reduced, becoming maximum for 1 μm triangles, which is the characteristic length scale set by domain wall width.

  8. N=1 domain wall solutions of massive type II supergravity as generalized geometries

    International Nuclear Information System (INIS)

    Louis, J.

    2006-05-01

    We study N=1 domain wall solutions of type IIB supergravity compactified on a Calabi-Yau manifold in the presence of RR and NS electric and magnetic fluxes. We show that the dynamics of the scalar fields along the direction transverse to the domain wall is described by gradient flow equations controlled by a superpotential W. We then provide a geometrical interpretation of the gradient flow equations in terms of the mirror symmetric compactification of type IIA. They correspond to a set of generalized Hitchin flow equations of a manifold with SU(3) x SU(3)structure which is fibered over the direction transverse to the domain wall. (Orig.)

  9. Supertube domain walls and elimination of closed timelike curves in string theory

    International Nuclear Information System (INIS)

    Drukker, Nadav

    2004-01-01

    We show that some novel physics of supertubes removes closed timelike curves from many supersymmetric spaces which naively suffer from this problem. The main claim is that supertubes naturally form domain walls, so while analytical continuation of the metric would lead to closed timelike curves, across the domain wall the metric is nondifferentiable, and the closed timelike curves are eliminated. In the examples we study, the metric inside the domain wall is always of the Goedel type, while outside the shell it looks like a localized rotating object, often a rotating black hole. Thus this mechanism prevents the appearance of closed timelike curves behind the horizons of certain rotating black holes

  10. Domain wall displacements in amorphous films and multilayers studied with a magnetic force microscope

    International Nuclear Information System (INIS)

    Pokhil, T.G.

    1997-01-01

    The magnetic force microscope (MFM) was used to study the displacement of domain walls (DW) in amorphous TbFe alloy films and Co/Pd multilayer films with high spatial resolution. The reversible bending of domain wall segments pinned to defects and irreversible, jumplike displacement of domain wall segments were imaged with the MFM in an applied magnetic field. The maximum reversible displacement of domain walls was 50 endash 100 nm and the length of the segments which reversibly curved in the field was about 150 nm. Measurement of the change in radius of curvature of a DW segment in response to an applied field allowed estimation of the DW energy density and self-demagnetizing field of the film acting on the DW. The DW energy density for the TbFe films was about 1 erg/cm 2 . It was shown that the self-demagnetizing field acting on a domain wall depends on the domain structure surrounding the studied DW segment. For instance, for a film with saturation magnetization 100 G and thickness 80 nm, which exhibited a mazelike domain structure, the demagnetizing field varied from 100 G in the center of a mazelike domain to 400 G near the edge of a domain. The irreversible displacement of a DW was not a continuous process. The 200 endash 400 nm long DW segments exhibited jumplike motion over distances of 100 endash 150 nm. copyright 1997 American Institute of Physics

  11. Unidirectional effect in domain wall propagation observed in bistable glass-coated microwire

    Energy Technology Data Exchange (ETDEWEB)

    Onufer, J., E-mail: jozef.onufer@tuke.sk; Ziman, J., E-mail: jan.ziman@tuke.sk; Kladivová, M., E-mail: maria.kladivova@tuke.sk

    2015-12-15

    Systematic study of domain wall velocity versus applied magnetic field dependences in glass-coated amorphous Fe{sub 77.5}Si{sub 7.5}B{sub 15} wire was carried out, revealing the existence of a very interesting phenomenon. Domain wall mobility can be significantly different in cases when magnetization reversal caused by domain wall motion results in different orientation of magnetization. The magnitude and sign of this so-called unidirectional effect can change along the wire. There are also samples with weak unidirectional effect in which it is possible, in regions of higher values of applied magnetic field, to observe the highest wall velocities. It is very probable that damping of domain wall motion is responsible for this effect. As a hypothesis a mechanism based on eddy current damping of domain wall motion was proposed for interpretation of this effect. In the framework of this mechanism asymmetric and non-linear volt-ampere characteristics of the metal–glass interface might be responsible for the unidirectional effect. - Highlights: • Unidirectional effect in domain wall propagation was observed. • The magnitude and sign of the unidirectional effect can change along the wire. • A hypothesis for interpretation of the unidirectional effect is proposed.

  12. Laccases Direct Lignification in the Discrete Secondary Cell Wall Domains of Protoxylem1[W][OPEN

    Science.gov (United States)

    Schuetz, Mathias; Benske, Anika; Smith, Rebecca A.; Watanabe, Yoichiro; Tobimatsu, Yuki; Ralph, John; Demura, Taku; Ellis, Brian; Samuels, A. Lacey

    2014-01-01

    Plants precisely control lignin deposition in spiral or annular secondary cell wall domains during protoxylem tracheary element (TE) development. Because protoxylem TEs function to transport water within rapidly elongating tissues, it is important that lignin deposition is restricted to the secondary cell walls in order to preserve the plasticity of adjacent primary wall domains. The Arabidopsis (Arabidopsis thaliana) inducible VASCULAR NAC DOMAIN7 (VND7) protoxylem TE differentiation system permits the use of mutant backgrounds, fluorescent protein tagging, and high-resolution live-cell imaging of xylem cells during secondary cell wall development. Enzymes synthesizing monolignols, as well as putative monolignol transporters, showed a uniform distribution during protoxylem TE differentiation. By contrast, the oxidative enzymes LACCASE4 (LAC4) and LAC17 were spatially localized to secondary cell walls throughout protoxylem TE differentiation. These data support the hypothesis that precise delivery of oxidative enzymes determines the pattern of cell wall lignification. This view was supported by lac4lac17 mutant analysis demonstrating that laccases are necessary for protoxylem TE lignification. Overexpression studies showed that laccases are sufficient to catalyze ectopic lignin polymerization in primary cell walls when exogenous monolignols are supplied. Our data support a model of protoxylem TE lignification in which monolignols are highly mobile once exported to the cell wall, and in which precise targeting of laccases to secondary cell wall domains directs lignin deposition. PMID:25157028

  13. Laccases direct lignification in the discrete secondary cell wall domains of protoxylem.

    Science.gov (United States)

    Schuetz, Mathias; Benske, Anika; Smith, Rebecca A; Watanabe, Yoichiro; Tobimatsu, Yuki; Ralph, John; Demura, Taku; Ellis, Brian; Samuels, A Lacey

    2014-10-01

    Plants precisely control lignin deposition in spiral or annular secondary cell wall domains during protoxylem tracheary element (TE) development. Because protoxylem TEs function to transport water within rapidly elongating tissues, it is important that lignin deposition is restricted to the secondary cell walls in order to preserve the plasticity of adjacent primary wall domains. The Arabidopsis (Arabidopsis thaliana) inducible VASCULAR NAC DOMAIN7 (VND7) protoxylem TE differentiation system permits the use of mutant backgrounds, fluorescent protein tagging, and high-resolution live-cell imaging of xylem cells during secondary cell wall development. Enzymes synthesizing monolignols, as well as putative monolignol transporters, showed a uniform distribution during protoxylem TE differentiation. By contrast, the oxidative enzymes LACCASE4 (LAC4) and LAC17 were spatially localized to secondary cell walls throughout protoxylem TE differentiation. These data support the hypothesis that precise delivery of oxidative enzymes determines the pattern of cell wall lignification. This view was supported by lac4lac17 mutant analysis demonstrating that laccases are necessary for protoxylem TE lignification. Overexpression studies showed that laccases are sufficient to catalyze ectopic lignin polymerization in primary cell walls when exogenous monolignols are supplied. Our data support a model of protoxylem TE lignification in which monolignols are highly mobile once exported to the cell wall, and in which precise targeting of laccases to secondary cell wall domains directs lignin deposition. © 2014 American Society of Plant Biologists. All Rights Reserved.

  14. Study of the structure of ferroelectric domain walls in barium titanate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Normand, L.; Thorel, A. [Centre des Materiaux, Evry cedex (France) ; Kilaas, R. [Lawrence Berkeley Lab., CA (United States); Montardi, Y. [Rhone-Poulenc, CRA, Aubervilliers (France)

    1995-02-01

    Structure of 90{degree} ferroelectric domain boundaries in barium titanate ceramics has been studied by means of Transmission Electron Microscopy and High Resolution TEM. Tilts of specific fringes across domain walls are measured on HREM images and Selected Area Diffraction Patterns. They are in a good agreement with the twin model admitted for these domain boundaries. A computerized method has been developed to give access to quantitative information about atomic displacements across these ferroelectric domain walls. The so calculated displacement field is then compared with Landau-Ginzburg based theoretical predictions.

  15. Stable branches of a solution for a fermion on domain wall

    Energy Technology Data Exchange (ETDEWEB)

    Gani, V. A. [National Research Nuclear University MEPhI, Department of Mathematics (Russian Federation); Ksenzov, V. G.; Kudryavtsev, A. E. [Institute for Theoretical and Experimental Physics (Russian Federation)

    2011-05-15

    The case when a fermion occupies an excited nonzero frequency level in the field of domain wall is discussed. It is demonstrated that a solution exists for the coupling constant in the limited interval 1 < g < g{sub max} Almost-Equal-To 1.65. It is shown that indeed there are different branches of stable solution for g in this interval. The first one corresponds to a fermion located on the domain wall (1 < g < 4{radical}2{pi}). The second branch, which belongs to the interval 4{radical}2{pi} {<=} g {<=} g{sub max}, describes a polarized fermion off the domain wall. The third branch with 1 < g < g{sub max} describes an excited antifermion in the field of the domain wall.

  16. Search for domain wall dark matter with atomic clocks on board global positioning system satellites.

    Science.gov (United States)

    Roberts, Benjamin M; Blewitt, Geoffrey; Dailey, Conner; Murphy, Mac; Pospelov, Maxim; Rollings, Alex; Sherman, Jeff; Williams, Wyatt; Derevianko, Andrei

    2017-10-30

    Cosmological observations indicate that dark matter makes up 85% of all matter in the universe yet its microscopic composition remains a mystery. Dark matter could arise from ultralight quantum fields that form macroscopic objects. Here we use the global positioning system as a ~ 50,000 km aperture dark matter detector to search for such objects in the form of domain walls. Global positioning system navigation relies on precision timing signals furnished by atomic clocks. As the Earth moves through the galactic dark matter halo, interactions with domain walls could cause a sequence of atomic clock perturbations that propagate through the satellite constellation at galactic velocities ~ 300 km s -1 . Mining 16 years of archival data, we find no evidence for domain walls at our current sensitivity level. This improves the limits on certain quadratic scalar couplings of domain wall dark matter to standard model particles by several orders of magnitude.

  17. Unidirectional Magnon-Driven Domain Wall Motion due to Interfacial Dzyaloshinskii-Moriya Interaction

    KAUST Repository

    Lee, Seo-Won

    2018-03-28

    We theoretically study magnon-driven motion of a tranverse domain wall in the presence of interfacial Dzyaloshinskii-Moriya interaction (DMI). Contrary to previous studies, the domain wall moves along the same direction regardless of the magnon-flow direction. Our symmetry analysis reveals that the odd order DMI contributions to the domain wall velocity are independent of the magnon-flow direction. Corresponding DMI-induced asymmetric transitions from a spin-wave state to another give rise to a large momentum transfer to the domain wall without nonreciprocity and much reflection. This counterintuitive unidirectional motion occurs not only for a spin wave with a single wavevector but also for thermal magnons with distributed wavevectors.

  18. Adiabatic spin-transfer-torque-induced domain wall creep in a magnetic metal

    Science.gov (United States)

    Duttagupta, S.; Fukami, S.; Zhang, C.; Sato, H.; Yamanouchi, M.; Matsukura, F.; Ohno, H.

    2016-04-01

    The dynamics of elastic interfaces is a general field of interest in statistical physics, where magnetic domain wall has served as a prototypical example. Domain wall `creep’ under the action of sub-threshold driving forces with thermal activation is known to be described by a scaling law with a certain universality class, which represents the mechanism of the interaction of domain walls with the applied forces over the disorder of the system. Here we show different universality classes depending on the driving forces, magnetic field or spin-polarized current, in a metallic system, which have hitherto been seen only in a magnetic semiconductor. We reveal that an adiabatic spin-transfer torque plays a major role in determining the universality class of current-induced creep, which does not depend on the intricacies of material disorder. Our results shed light on the physics of the creep motion of domain walls and other elastic systems.

  19. One-dimensional in-plane edge domain walls in ultrathin ferromagnetic films

    Science.gov (United States)

    Lund, Ross G.; Muratov, Cyrill B.; Slastikov, Valeriy V.

    2018-03-01

    We study existence and properties of 1D edge domain walls in ultrathin ferromagnetic films with uniaxial in-plane magnetic anisotropy. In these materials, the magnetization vector is constrained to lie entirely in the film plane, with the preferred directions dictated by the magnetocrystalline easy axis. We consider magnetization profiles in the vicinity of a straight film edge oriented at an arbitrary angle with respect to the easy axis. To minimize the micromagnetic energy, these profiles form transition layers in which the magnetization vector rotates away from the direction of the easy axis to align with the film edge. We prove existence of edge domain walls as minimizers of the appropriate 1D micromagnetic energy functional and show that they are classical solutions of the associated Euler–Lagrange equation with a Dirichlet boundary condition at the edge. We also perform a numerical study of these 1D domain walls and uncover further properties of these domain wall profiles.

  20. Domain-wall curvature and coercivity in pinning type Sm endash Co magnets

    International Nuclear Information System (INIS)

    Skomski, R.

    1997-01-01

    The origin of coercivity in precipitation hardened Sm endash Co magnets is investigated. By considering domain-wall pinning at boundary phase and Z phase inhomogenities, it is found that the hexagonal Z phase has no direct influence on the coercivity. The intuitive assumption of plane domain walls made in a recent calculation is unrealistic but has no direct effect on the coercivity. However, due to the comparatively large size of the 12:17 cells, the calculated three dimensional domain-wall curvature is sufficiently large to assure a nearly ideal nestling of the domain walls to the 1:5 cell boundary. This nestling yields a coercivity increase from about 0.1 to about 1 T and is therefore responsible for the high coercivity of 2:17 based Sm endash Co magnets. copyright 1997 American Institute of Physics

  1. Magnetic hysteresis and domain wall dynamics in single chain magnets with antiferromagnetic interchain coupling

    Energy Technology Data Exchange (ETDEWEB)

    Bukharov, A A; Ovchinnikov, A S; Baranov, N V [Department of Physics, Ural State University, Ekaterinburg, 620083 (Russian Federation); Inoue, K [Institute for Advanced Materials Research, Hiroshima University, Hiroshima (Japan)

    2010-11-03

    Using Monte Carlo simulations we investigate magnetic hysteresis in two- and three-dimensional systems of weakly antiferromagnetically coupled spin chains based on a scenario of domain wall (kink) motion within the chains. By adapting the model of walkers to simulate the domain wall dynamics and using the Ising-like dipole-dipole model, we study the effects of interchain coupling, temperature and anisotropy axis direction on hysteresis curves.

  2. Domain wall solitons and Hopf algebraic translational symmetries in noncommutative field theories

    International Nuclear Information System (INIS)

    Sasai, Yuya; Sasakura, Naoki

    2008-01-01

    Domain wall solitons are the simplest topological objects in field theories. The conventional translational symmetry in a field theory is the generator of a one-parameter family of domain wall solutions, and induces a massless moduli field which propagates along a domain wall. We study similar issues in braided noncommutative field theories possessing Hopf algebraic translational symmetries. As a concrete example, we discuss a domain wall soliton in the scalar φ 4 braided noncommutative field theory in Lie-algebraic noncommutative space-time, [x i ,x j ]=2iκε ijk x k (i,j,k=1,2,3), which has a Hopf algebraic translational symmetry. We first discuss the existence of a domain wall soliton in view of Derrick's theorem, and construct explicitly a one-parameter family of solutions in perturbation of the noncommutativity parameter κ. We then find the massless moduli field which propagates on the domain wall soliton. We further extend our analysis to the general Hopf algebraic translational symmetry

  3. Mobility of ferroelastic domain walls in barium titanate

    Czech Academy of Sciences Publication Activity Database

    Hlinka, Jiří

    2007-01-01

    Roč. 349, - (2007), s. 49-54 ISSN 0015-0193 R&D Projects: GA ČR GA202/06/0411 Institutional research plan: CEZ:AV0Z10100520 Keywords : ferroelectric and ferroelastic domains * BaTiO 3 * Ginzburg-Landau theory * mobility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.427, year: 2007

  4. Crossed ratchet effects on magnetic domain walls: geometry and transverse field effects

    Energy Technology Data Exchange (ETDEWEB)

    Alija, A; Hierro-Rodriguez, A; Perez-Junquera, A; Alameda, J M; Martin, J I; Velez, M, E-mail: mvelez@uniovi.es [Dept. Fisica, Universidad de Oviedo-CINN, 33007 Oviedo (Spain)

    2011-08-17

    Domain wall propagation across a 2D array of asymmetric holes is strongly dependent on the domain wall configuration: i.e. on whether the wall is flat or kinked. This results in interesting crossed ratchet and asymmetric accommodation effects that have been studied as a function of geometry and transverse field. Micromagnetic simulations have shown that the observation of crossed ratchet effects is easier for arrow than for triangular holes due to a larger field range in which kink propagation is the preferred mode for domain wall motion. Also, it has been found that dc transverse fields can produce a significant enhancement of the easy axis asymmetric accommodation and, also, that ac transverse fields can be rectified by the crossed ratchet potential.

  5. Domain Walls and Textured Vortices in a Two-Component Ginzburg-Landau Model

    DEFF Research Database (Denmark)

    Madsen, Søren Peder; Gaididei, Yu. B.; Christiansen, Peter Leth

    2005-01-01

    We look for domain wall and textured vortex solutions in a two-component Ginzburg-Landau model inspired by two-band superconductivity. The two-dimensional two-component model, with equal coherence lengths and no magnetic field, shows some interesting properties. In the absence of a Josephson type...... coupling between the two order parameters a ''textured vortex'' is found by analytical and numerical solution of the Ginzburg-Landau equations. With a Josephson type coupling between the two order parameters we find the system to split up in two domains separated by a domain wall, where the order parameter...

  6. Ferroelastic domain walls in barium titanate - quantitative phenomenological model

    Czech Academy of Sciences Publication Activity Database

    Hlinka, Jiří; Márton, Pavel

    2009-01-01

    Roč. 101, č. 1 (2009), s. 50-62 ISSN 1058-4587 R&D Projects: GA ČR GA202/06/0411; GA ČR(CZ) GD202/05/H003; GA AV ČR 1ET300100401 Institutional research plan: CEZ:AV0Z10100520 Keywords : ferroelectric and ferroelastic domains * BaTiO 3 * Ginzburg-Landau theory Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.329, year: 2009

  7. The defects influence on domain wall propagation in bistable glass-coated microwires

    Energy Technology Data Exchange (ETDEWEB)

    Rodionova, V. [Magnetism Division, Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Immanuel Kant Baltic Federal University, Kaliningrad 236041 (Russian Federation); Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, San Sebastian 20018 (Spain); Zhukova, V., E-mail: valentina.zhukova@ehu.es [Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, San Sebastian 20018 (Spain); Ilyn, M.; Ipatov, M. [Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, San Sebastian 20018 (Spain); Perov, N. [Magnetism Division, Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Zhukov, A. [Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, San Sebastian 20018 (Spain); IKERBASQUE, Basque Foundation for Science, Bilbao 48011 (Spain)

    2012-05-01

    We studied the domain wall (DW) dynamics of magnetically bistable amorphous glass-coated Fe{sub 74}B{sub 13}Si{sub 11}C{sub 2} microwires. In according to our experimental results magnetic field dependences of DW velocity of studied microwires can be divided into two groups: with uniform or uniformly accelerated DW propagation along the microwire. Strong correlation between the type of the magnetic field dependence of domain wall velocity, v(H), and the distribution of the local nucleation fields has been observed. Moreover, we observed abrupt increasing of DW velocity (jump) on the magnetic field dependences of the domain wall velocity, v(H), for the both types of the v(H) dependences. At the same time usual linear increasing of the domain wall velocity with magnetic field persists below these jumps. It was found that the jump height correlates with the location of nucleation place of the new domain wall. We have measured local nucleation field distribution in all the microwires. From local nucleation field distribution we have obtained the DW nucleation locations and estimated the jump height.

  8. The defects influence on domain wall propagation in bistable glass-coated microwires

    International Nuclear Information System (INIS)

    Rodionova, V.; Zhukova, V.; Ilyn, M.; Ipatov, M.; Perov, N.; Zhukov, A.

    2012-01-01

    We studied the domain wall (DW) dynamics of magnetically bistable amorphous glass-coated Fe 74 B 13 Si 11 C 2 microwires. In according to our experimental results magnetic field dependences of DW velocity of studied microwires can be divided into two groups: with uniform or uniformly accelerated DW propagation along the microwire. Strong correlation between the type of the magnetic field dependence of domain wall velocity, v(H), and the distribution of the local nucleation fields has been observed. Moreover, we observed abrupt increasing of DW velocity (jump) on the magnetic field dependences of the domain wall velocity, v(H), for the both types of the v(H) dependences. At the same time usual linear increasing of the domain wall velocity with magnetic field persists below these jumps. It was found that the jump height correlates with the location of nucleation place of the new domain wall. We have measured local nucleation field distribution in all the microwires. From local nucleation field distribution we have obtained the DW nucleation locations and estimated the jump height

  9. Domain wall dynamics in ultrathin Pt/Co/AlOx microstrips under large combined magnetic fields

    Science.gov (United States)

    Jué, E.; Thiaville, A.; Pizzini, S.; Miltat, J.; Sampaio, J.; Buda-Prejbeanu, L. D.; Rohart, S.; Vogel, J.; Bonfim, M.; Boulle, O.; Auffret, S.; Miron, I. M.; Gaudin, G.

    2016-01-01

    The dynamics of magnetic domain walls in ultrathin strip-patterned Pt/Co/AlOx samples with perpendicular easy axis has been studied experimentally under an easy-axis field, superposed to a hard-axis field oriented along the strip. The easy-axis field is large so that the domain walls move well beyond the creep regime. A chiral effect is observed where the domain wall velocity shows a monotonous and surprisingly large variation with an in-plane field. A micromagnetic analysis, combining analytic, one-dimensional, and two-dimensional simulations with structural disorder, shows that this behavior can be reproduced with a Dzyaloshinskii-Moriya interaction of the interfacial type, with due consideration of the dynamics of the tilt degree of freedom of the domain wall. The estimated effective value of this interaction (D ≈-2.2 mJ /m2 for a 0.6 nm Co thickness) is consistent with values obtained by other techniques. It is also shown, by micromagnetic analysis, that several modes and characteristic times occur in the dynamics of the tilt of such domain walls.

  10. Proposal for a Domain Wall Nano-Oscillator driven by Non-uniform Spin Currents

    Science.gov (United States)

    Sharma, Sanchar; Muralidharan, Bhaskaran; Tulapurkar, Ashwin

    2015-09-01

    We propose a new mechanism and a related device concept for a robust, magnetic field tunable radio-frequency (rf) oscillator using the self oscillation of a magnetic domain wall subject to a uniform static magnetic field and a spatially non-uniform vertical dc spin current. The self oscillation of the domain wall is created as it translates periodically between two unstable positions, one being in the region where both the dc spin current and the magnetic field are present, and the other, being where only the magnetic field is present. The vertical dc spin current pushes it away from one unstable position while the magnetic field pushes it away from the other. We show that such oscillations are stable under noise and can exhibit a quality factor of over 1000. A domain wall under dynamic translation, not only being a source for rich physics, is also a promising candidate for advancements in nanoelectronics with the actively researched racetrack memory architecture, digital and analog switching paradigms as candidate examples. Devising a stable rf oscillator using a domain wall is hence another step towards the realization of an all domain wall logic scheme.

  11. Electric-field control of magnetic domain-wall velocity in ultrathin cobalt with perpendicular magnetization.

    Science.gov (United States)

    Chiba, D; Kawaguchi, M; Fukami, S; Ishiwata, N; Shimamura, K; Kobayashi, K; Ono, T

    2012-06-06

    Controlling the displacement of a magnetic domain wall is potentially useful for information processing in magnetic non-volatile memories and logic devices. A magnetic domain wall can be moved by applying an external magnetic field and/or electric current, and its velocity depends on their magnitudes. Here we show that the applying an electric field can change the velocity of a magnetic domain wall significantly. A field-effect device, consisting of a top-gate electrode, a dielectric insulator layer, and a wire-shaped ferromagnetic Co/Pt thin layer with perpendicular anisotropy, was used to observe it in a finite magnetic field. We found that the application of the electric fields in the range of ± 2-3 MV cm(-1) can change the magnetic domain wall velocity in its creep regime (10(6)-10(3) m s(-1)) by more than an order of magnitude. This significant change is due to electrical modulation of the energy barrier for the magnetic domain wall motion.

  12. Metallic Interface Emerging at Magnetic Domain Wall of Antiferromagnetic Insulator: Fate of Extinct Weyl Electrons

    Directory of Open Access Journals (Sweden)

    Youhei Yamaji

    2014-05-01

    Full Text Available Topological insulators, in contrast to ordinary semiconductors, accompany protected metallic surfaces described by Dirac-type fermions. Here, we theoretically show that another emergent two-dimensional metal embedded in the bulk insulator is realized at a magnetic domain wall. The domain wall has long been studied as an ingredient of both old-fashioned and leading-edge spintronics. The domain wall here, as an interface of seemingly trivial antiferromagnetic insulators, emergently realizes a functional interface preserved by zero modes with robust two-dimensional Fermi surfaces, where pyrochlore iridium oxides proposed to host the condensed-matter realization of Weyl fermions offer such examples at low temperatures. The existence of in-gap states that are pinned at domain walls, theoretically resembling spin or charge solitons in polyacetylene, and protected as the edges of hidden one-dimensional weak Chern insulators characterized by a zero-dimensional class-A topological invariant, solves experimental puzzles observed in R_{2}Ir_{2}O_{7} with rare-earth elements R. The domain wall realizes a novel quantum confinement of electrons and embosses a net uniform magnetization that enables magnetic control of electronic interface transports beyond the semiconductor paradigm.

  13. A micromagnetic study of the oscillations of pinned domain walls in magnetic ribbons

    International Nuclear Information System (INIS)

    Alejos, Oscar; Torres, Carlos; Hernandez-Gomez, Pablo; Lopez-Diaz, Luis; Torres, Luis; Martinez, Eduardo

    2007-01-01

    The work studies the dynamics of domain walls in magnetic ribbons with thicknesses of the order of magnitude of the permalloy exchange length (5.7 nm) by means of micromagnetic simulations. Two small defects are symmetrically placed on both edges of the ribbon, one on each edge, occupying the whole ribbon thickness. One transverse domain wall is pinned by the defects, in a head-to-head configuration. A free wall oscillation is forced by applying a static external magnetic field in the direction of the large axis until the wall reaches a new equilibrium position (elongation), and then removed. Three dynamic regimes are observed depending on the size of the cross ribbon section

  14. Domain Wall Motion in Magnetic Nanostrips under the Influence of Rashba Field

    Directory of Open Access Journals (Sweden)

    Vito Puliafito

    2012-01-01

    Full Text Available Spin-orbit Rashba effect applies a torque on the magnetization of a ferromagnetic nanostrip in the case of structural inversion asymmetry, also affecting the steady domain wall motion induced by a spin-polarized current. This influence is here analytically studied in the framework of the extended Landau-Lifshitz-Gilbert equation, including the Rashba effect as an additive term of the effective field. Results of previous micromagnetic simulations and experiments have shown that this field yields an increased value of the Walker breakdown current together with an enlargement of the domain wall width. In order to analytically describe these results, the standard travelling wave ansatz for the steady domain wall motion is here adopted. Results of our investigations reveal the impossibility to reproduce, at the same time, the previous features and suggest the need of a more sophisticated model whose development requires, in turn, additional information to be extracted from ad hoc micromagnetic simulations.

  15. Resonant electron tunnelling assisted by charged domain walls in multiferroic tunnel junctions

    Science.gov (United States)

    Sanchez-Santolino, Gabriel; Tornos, Javier; Hernandez-Martin, David; Beltran, Juan I.; Munuera, Carmen; Cabero, Mariona; Perez-Muñoz, Ana; Ricote, Jesus; Mompean, Federico; Garcia-Hernandez, Mar; Sefrioui, Zouhair; Leon, Carlos; Pennycook, Steve J.; Muñoz, Maria Carmen; Varela, Maria; Santamaria, Jacobo

    2017-07-01

    The peculiar features of domain walls observed in ferroelectrics make them promising active elements for next-generation non-volatile memories, logic gates and energy-harvesting devices. Although extensive research activity has been devoted recently to making full use of this technological potential, concrete realizations of working nanodevices exploiting these functional properties are yet to be demonstrated. Here, we fabricate a multiferroic tunnel junction based on ferromagnetic La0.7Sr0.3MnO3 electrodes separated by an ultrathin ferroelectric BaTiO3 tunnel barrier, where a head-to-head domain wall is constrained. An electron gas stabilized by oxygen vacancies is confined within the domain wall, displaying discrete quantum-well energy levels. These states assist resonant electron tunnelling processes across the barrier, leading to strong quantum oscillations of the electrical conductance.

  16. Reconfigurable magnetic domain wall pinning using vortex-generated magnetic fields

    Science.gov (United States)

    Hurst, Aaron C. H.; Izaac, Joshua A.; Altaf, Fouzia; Baltz, Vincent; Metaxas, Peter J.

    2017-05-01

    Although often important for domain wall device applications, reproducible fabrication of pinning sites at the nano-scale remains challenging. Here, we demonstrate that the stray magnetic field generated beneath magnetic vortex cores can be used to generate localized pinning sites for magnetic domain walls in an underlying, perpendicularly magnetized nanostrip. Moreover, we show that the pinning strength can be tuned by switching the vortex core polarity: switching the core polarity so that it is aligned with the magnetization of the expanding domain (rather than against it) can reduce the vortex-mediated wall depinning field by between 40% and 90%, depending on the system geometry. Significant reductions in the depinning field are also demonstrated in narrow strips by shifting the core away from the strips' centers.

  17. Excitation transport through a domain wall in a Bose-Einstein condensate

    Science.gov (United States)

    Watabe, Shohei; Kato, Yusuke; Ohashi, Yoji

    2012-08-01

    We investigate the tunneling properties of collective excitations through a domain wall in the ferromagnetic phase of a spin-1 spinor Bose-Einstein condensate. Within the mean-field theory at T=0, we show that the transverse spin wave undergoes perfect reflection in the low-energy limit. This reflection property differs considerably from that of a domain wall in a Heisenberg ferromagnet where spin-wave excitations exhibit perfect transmission at arbitrary energy. When the Bogoliubov mode is scattered from this domain wall soliton, the transmission and reflection coefficients exhibit pronounced nonmonotonicity. In particular, we find perfect reflection of the Bogoliubov mode at energies where bound states appear. This is in stark contrast to the perfect transmission of the Bogoliubov mode with arbitrary energy through a dark soliton in a scalar Bose-Einstein condensate.

  18. Quasi-one-dimensional solutions for domain walls and their constraints in improper ferroelastics

    Energy Technology Data Exchange (ETDEWEB)

    Cao, W. (Materials Research Laboratory, Pennsylvania State University,University Park, PA (USA) Department of Physics, Pennsylvania StateUniversity, University Park, PA (USA) Laboratory of Atomic Solid State Physics, Cornell University, Ithaca, NY (USA)); Barsch, G.R. (Materials Research Laboratory, Pennsylvania University, University Park, PA (USA) Department of Physics, Pennsylvania State University, University Park, PA (USA)); Krumhansl, J.A. (Laboratory of Atomic and Solid StatePhysics, Cornell University, Ithaca, NY (USA))

    1990-10-01

    Based on a Landau-Ginzburg model for improper ferroelastic perovskites, we have analyzed quasi-one-dimensional (Q1D) solutions for twin boundaries (domain walls) and the associated constraints. Because of the coupling of the order parameter to the elastic strain, in general domain walls must be described by fully three-dimensional (3D) solutions. Q1D solutions exist only with the presence of one of the following: (i) body force, (ii) surface stress, and (iii) interface dislocations. The shape change induced by the domain wall is also discussed for each of the above three cases. These conclusions hold quite generally for all Landau-Ginzburg models of improper ferroelastics.

  19. Excess velocity of magnetic domain walls close to the depinning field

    Science.gov (United States)

    Caballero, Nirvana B.; Fernández Aguirre, Iván; Albornoz, Lucas J.; Kolton, Alejandro B.; Rojas-Sánchez, Juan Carlos; Collin, Sophie; George, Jean Marie; Diaz Pardo, Rebeca; Jeudy, Vincent; Bustingorry, Sebastian; Curiale, Javier

    2017-12-01

    Magnetic field driven domain wall velocities in [Co/Ni] based multilayers thin films have been measured using polar magneto-optic Kerr effect microscopy. The low field results are shown to be consistent with the universal creep regime of domain wall motion, characterized by a stretched exponential growth of the velocity with the inverse of the applied field. Approaching the depinning field from below results in an unexpected excess velocity with respect to the creep law. We analyze these results using scaling theory to show that this speeding up of domain wall motion can be interpreted as due to the increase of the size of the deterministic relaxation close to the depinning transition. We propose a phenomenological model to accurately fit the observed excess velocity and to obtain characteristic values for the depinning field Hd, the depinning temperature Td, and the characteristic velocity scale v0 for each sample.

  20. Asymmetric driven dynamics of Dzyaloshinskii domain walls in ultrathin ferromagnetic strips with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Tejerina, L. [Dpto. Electricidad y Electrónica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid (Spain); Alejos, Ó., E-mail: oscaral@ee.uva.es [Dpto. Electricidad y Electrónica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid (Spain); Martínez, E. [Dpto. Física Aplicada, Facultad de Ciencias, Universidad de Salamanca, 37011 Salamanca (Spain); Muñoz, J.M. [Dpto. Electricidad y Electrónica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid (Spain)

    2016-07-01

    The dynamics of domain walls in ultrathin ferromagnetic strips with perpendicular magnetic anisotropy is studied from both numerical and analytical micromagnetics. The influence of a moderate interfacial Dzyaloshinskii–Moriya interaction associated to a bi-layer strip arrangement has been considered, giving rise to the formation of Dzyaloshinskii domain walls. Such walls possess under equilibrium conditions an inner magnetization structure defined by a certain orientation angle that make them to be considered as intermediate configurations between Bloch and Néel walls. Two different dynamics are considered, a field-driven and a current-driven dynamics, in particular, the one promoted by the spin torque due to the spin-Hall effect. Results show an inherent asymmetry associated with the rotation of the domain wall magnetization orientation before reaching the stationary regime, characterized by a constant terminal speed. For a certain initial DW magnetization orientation at rest, the rotation determines whether the reorientation of the DW magnetization prior to reach stationary motion is smooth or abrupt. This asymmetry affects the DW motion, which can even reverse for a short period of time. Additionally, it is found that the terminal speed in the case of the current-driven dynamics may depend on either the initial DW magnetization orientation at rest or the sign of the longitudinally injected current. - Highlights: • The asymmetric response of domain walls in bilayer strips with PMA is studied. • Out-of-plane fields and SHE longitudinal currents are applied. • The response is associated to the rotation of the domain wall inner magnetization. • Clockwise and counter-clockwise magnetization rotations are not equivalent. • The asymmetry results in different travelled distances and/or terminal speeds.

  1. On the equilibrium configuration of the Kittel type domain structure with Bloch walls, l80deg

    International Nuclear Information System (INIS)

    Gavrila, H.

    1975-01-01

    Using a phenomenologic method for appreciating different components of the free energy, the equilibrium configuration of the Kittel-type domain structure with Bloch walls is obtained. By improving the known methods, more accurate magnetostatic energy calculations are reported. In order to determine the equilibrium structure, the total free energy is minimized with respect to two system parameters: the Bloch wall width and the structure half-period. (author)

  2. Endolysin of bacteriophage BFK20: evidence of a catalytic and a cell wall binding domain.

    Science.gov (United States)

    Gerova, Martina; Halgasova, Nora; Ugorcakova, Jana; Bukovska, Gabriela

    2011-08-01

    A gene product of ORF24' was identified on the genome of corynephage BFK20 as a putative phage endolysin. The protein of endolysin BFK20 (gp24') has a modular structure consisting of an N-terminal amidase_2 domain (gp24CD) and a C-terminal cell wall binding domain (gp24BD). The C-terminal domain is unrelated to any of the known cell wall binding domains of phage endolysins. The whole endolysin gene and the sequences of its N-terminal and C-terminal domains were cloned; proteins were expressed in Escherichia coli and purified to homogeneity. The lytic activities of endolysin and its catalytic domain were demonstrated on corynebacteria and bacillus substrates. The binding activity of cell wall binding domain alone and in fusion with green fluorescent protein (gp24BD-GFP) were shown by specific binding assays to the cell surface of BFK20 host Brevibacterium flavum CCM 251 as well as those of other corynebacteria. 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  3. Magnetization reversal of the transverse domain wall confined between two clusters of magnetic impurities in a ferromagnetic planar nanowire

    International Nuclear Information System (INIS)

    Toscano, D.; Leonel, S.A.; Coura, P.Z.; Sato, F.; Costa, B.V.; Vázquez, M.

    2016-01-01

    Numerical simulations have been used to investigate the polarity reversal of the transverse domain wall in rectangular magnetic nanowires and the stabilization of the domain wall position after occurring the polarity reversal. In order to control the wall position we have considered two clusters of magnetic impurities, identical and equidistant from the nanowire width axis. Traps of pinning and blocking for the transverse domain wall can be originated from magnetic impurities, consisting of a local variation of the exchange constant. Under suitable excitation amplitudes it is possible to switch the polarity of the transverse domain wall by applying a nanosecond axial magnetic field pulse in a fast and controllable way. - Highlights: • Traps for pinning and blocking transverse domain walls are proposed. • The traps consisting of localized modifications of the magnetic properties. • The wall polarity can be reversed in a fast and controllable way.

  4. Magnetization reversal of the transverse domain wall confined between two clusters of magnetic impurities in a ferromagnetic planar nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Toscano, D., E-mail: danilotoscano@fisica.ufjf.br [Departamento de Física, Laboratório de Simulação Computacional, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais 36036–330 (Brazil); Leonel, S.A., E-mail: sidiney@fisica.ufjf.br [Departamento de Física, Laboratório de Simulação Computacional, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais 36036–330 (Brazil); Coura, P.Z., E-mail: pablo@fisica.ufjf.br [Departamento de Física, Laboratório de Simulação Computacional, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais 36036–330 (Brazil); Sato, F., E-mail: sjfsato@fisica.ufjf.br [Departamento de Física, Laboratório de Simulação Computacional, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais 36036–330 (Brazil); Costa, B.V., E-mail: bvc@fisica.ufmg.br [Departamento de Física, Laboratório de Simulação, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 30123–970 (Brazil); Vázquez, M., E-mail: mvazquez@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid, CSIC. 28049 Madrid (Spain)

    2016-12-01

    Numerical simulations have been used to investigate the polarity reversal of the transverse domain wall in rectangular magnetic nanowires and the stabilization of the domain wall position after occurring the polarity reversal. In order to control the wall position we have considered two clusters of magnetic impurities, identical and equidistant from the nanowire width axis. Traps of pinning and blocking for the transverse domain wall can be originated from magnetic impurities, consisting of a local variation of the exchange constant. Under suitable excitation amplitudes it is possible to switch the polarity of the transverse domain wall by applying a nanosecond axial magnetic field pulse in a fast and controllable way. - Highlights: • Traps for pinning and blocking transverse domain walls are proposed. • The traps consisting of localized modifications of the magnetic properties. • The wall polarity can be reversed in a fast and controllable way.

  5. Critical current density of domain wall oscillation due to spin-transfer torque

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, T; Imamura, H, E-mail: tomohiro-taniguchi@aist.go.jp, E-mail: h-imamura@aist.go.jp [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2011-04-01

    The domain wall oscillation due to spin-transfer torque was studied by numerically solving the Landau-Lifshitz-Gilbert (LLG) equation. For a domain wall whose rotation angle {theta}{sub max} is less than 180{sup 0}, we found the existence of the critical current density above which the magnetization dynamics are induced. We studied the dependence of the critical current density on the rotation angle {theta}{sub max} and found that the critical current density is proportional to 180{sup 0} - {theta}{sub max}.

  6. Control and braiding of Majorana fermions bound to magnetic domain walls

    Science.gov (United States)

    Kim, Se Kwon; Tewari, Sumanta; Tserkovnyak, Yaroslav

    2015-07-01

    Owing to the recent progress on endowing the electronic structure of magnetic nanowires with topological properties, the associated topological solitons in the magnetic texture—magnetic domain walls—appear as very natural hosts for exotic electronic excitations. Here, we propose to use the magnetic domain walls to engender Majorana fermions, which has several notable advantages compared to the existing approaches. First of all, the local tunneling density-of-states anomaly associated with the Majorana zero mode bound to a smooth magnetic soliton is immune to most of parasitic artifacts associated with the abrupt physical ends of a wire, which mar the existing experimental probes. Second, a viable route to move and braid Majorana fermions is offered by domain-wall motion. In particular, we envision the recently demonstrated heat-current induced motion of domain walls in insulating ferromagnets as a promising tool for nonintrusive displacement of Majorana modes. This leads us to propose a feasible scheme for braiding domain walls within a magnetic nanowire network, which manifests the nob-Abelian exchange statistics within the Majorana subspace.

  7. Internal friction due to domain-wall motion in martensitically transformed A15 compounds

    International Nuclear Information System (INIS)

    Snead, C.L. Jr.; Welch, D.O.

    1985-01-01

    A lattice instability in A15 materials in some cases leads to a cubic-to-tetragonal martensitic transformation at low temperatures. The transformed material orients in lamellae with c axes alternately aligned along the directions producing domain walls between the lamellae. An internal-friction (delta) feature below T/sub m/ is attributed to stress-induced domain-wall motion. The magnitude of the friction increases as temperature is lowered below T/sub m/ as (1-c/a) increases, and behaves as (1-c/a) 2 from T/sub m/ down to the superconducting critical temperature where the increasing tetragonality is inhibited. The effect of strain in the lattice is to decrease the domain-wall internal friction, but not affect T/sub m/. Neutron-induced disorder and the addition of some third-elements in alloying decrease both delta and T/sub m/, with some elements reducing only the former. Less than 1 at. % H is seen to completely suppress both delta and T/sub m. Martensitically transformed V 2 Zr demonstrates low-temperature internal-friction and modulus behavior consists with easy β/m wall motion relative to the easy m/m motion of the A15's. For the V 2 Zr, a peak in delta is observed, qualitatively in agreement with expected β/m wall motion

  8. Internal friction due to domain-wall motion in martensitically transformed A15 compounds

    Energy Technology Data Exchange (ETDEWEB)

    Snead, C.L. Jr.; Welch, D.O.

    1985-01-01

    A lattice instability in A15 materials in some cases leads to a cubic-to-tetragonal martensitic transformation at low temperatures. The transformed material orients in lamellae with c axes alternately aligned along the <100> directions producing domain walls between the lamellae. An internal-friction (delta) feature below T/sub m/ is attributed to stress-induced domain-wall motion. The magnitude of the friction increases as temperature is lowered below T/sub m/ as (1-c/a) increases, and behaves as (1-c/a)/sup 2/ from T/sub m/ down to the superconducting critical temperature where the increasing tetragonality is inhibited. The effect of strain in the lattice is to decrease the domain-wall internal friction, but not affect T/sub m/. Neutron-induced disorder and the addition of some third-elements in alloying decrease both delta and T/sub m/, with some elements reducing only the former. Less than 1 at. % H is seen to completely suppress both delta and T/sub m. Martensitically transformed V/sub 2/Zr demonstrates low-temperature internal-friction and modulus behavior consists with easy ..beta../m wall motion relative to the easy m/m motion of the A15's. For the V/sub 2/Zr, a peak in delta is observed, qualitatively in agreement with expected ..beta../m wall motion.

  9. Nonadiabatic Spin Torque Investigated Using Thermally Activated Magnetic Domain Wall Dynamics

    DEFF Research Database (Denmark)

    Eltschka, M.; Woetzel, Mathias; Rhensius, J.

    2010-01-01

    Using transmission electron microscopy, we investigate the thermally activated motion of domain walls (DWs) between two positions in Permalloy (Ni80Fe20) nanowires at room temperature. We show that this purely thermal motion is well described by an Arrhenius law, allowing for a description...

  10. Simulations of super-structure domain walls in two dimensional assemblies of magnetic nanoparticles

    DEFF Research Database (Denmark)

    Jordanovic, Jelena; Beleggia, Marco; Schiøtz, Jakob

    2015-01-01

    We simulate the formation of domain walls in two-dimensional assemblies of magnetic nanoparticles. Particle parameters are chosen to match recent electron holography and Lorentz microscopy studies of almost monodisperse cobalt nanoparticles assembled into regular, elongated lattices. As the parti......We simulate the formation of domain walls in two-dimensional assemblies of magnetic nanoparticles. Particle parameters are chosen to match recent electron holography and Lorentz microscopy studies of almost monodisperse cobalt nanoparticles assembled into regular, elongated lattices...... taking the role of the atomic spins. The coupling is, however, different. The superspins interact only by dipolar interactions as exchange coupling between individual nanoparticles may be neglected due to interparticle spacing. We observe that it is energetically favorable to introduce domain walls...... oriented along the long dimension of nanoparticle assemblies rather than along the short dimension. This is unlike what is typically observed in continuous magnetic materials, where the exchange interaction introduces an energetic cost proportional to the area of the domain walls. Structural disorder...

  11. Quark matter coupled to domain walls in Bianchi types II, VIII and IX ...

    Indian Academy of Sciences (India)

    In this study of Bianchi types II, VIII and IX Universes, quark matter coupled to domain walls in the context of general relativity are explored. To obtain deterministic solution of the Einstein's field equations, various techniques are adopted. The features of the obtained solution are discussed.

  12. Free-carrier-compensated charged domain walls produced with super-bandgap illumination in insulating ferroelectrics

    Czech Academy of Sciences Publication Activity Database

    Bednyakov, Petr; Sluka, T.; Tagantsev, A.; Damjanovic, D.; Setter, N.

    2016-01-01

    Roč. 28, č. 43 (2016), s. 9498-9503 ISSN 0935-9648 R&D Projects: GA ČR GA15-04121S Institutional support: RVO:68378271 Keywords : super-bandgap illumination * charged domain walls * ferroelectric BaTiO 3 * free-carrier generation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 19.791, year: 2016

  13. Analysis of domain wall dynamics based on skewness of magnetic Barkhausen noise for applied stress determination

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Song [College of Electrical Engineering and Control Science, Nanjing Tech University, Nanjing, Jiangsu 211816 (China); School of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China); Tian, GuiYun, E-mail: tian280@hotmail.com [School of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China); School of Electrical and Electronic Engineering, Merz Court, University of Newcastle upon Tyne, Newcastle NE1 7RU (United Kingdom); Dobmann, Gerd; Wang, Ping [School of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China)

    2017-01-01

    Skewness of Magnetic Barkhausen Noise (MBN) signal is used as a new feature for applied stress determination. After experimental studies, skewness presents its ability for measuring applied tensile stress compared with conventional feature, meanwhile, a non-linear behavior of this new feature and an independence of the excitation conditions under compressive stress are found and discussed. Effective damping during domain wall motion influencing the asymmetric shape of the MBN statistical distribution function is discussed under compressive and tensile stress variation. Domain wall (DW) energy and distance between pinning edges of the DW are considered altering the characteristic relaxation time, which is the reason for the non-linear phenomenon of skewness. - Highlights: • The skewness of magnetic Barkhausen noise profile is proposed as a new feature for applied stress determination. • The skewness is sensitive to applied stress and independent to excitation frequency. • Domain wall energy and pinning distance influence the relaxation time of domain wall, which leads to a non-linear behavior of skewness under compressive stress.

  14. Domain wall magnetoresistance in BiFeO3 thin films measured by scanning probe microscopy

    NARCIS (Netherlands)

    Domingo, N.; Farokhipoor, S.; Santiso, J.; Noheda, B.; Catalan, G.

    2017-01-01

    We measure the magnetotransport properties of individual 71 degrees domain walls in multiferroic BiFeO3 by means of conductive-atomic force microscopy (C-AFM) in the presence of magnetic fields up to one Tesla. The results suggest anisotropic magnetoresistance at room temperature, with the sign of

  15. Crossover from quantum tunneling to classical hopping of domain walls in ferromagnets

    Science.gov (United States)

    Zhou, Bin; Liang, Jiu-Qing; Pu, Fu-Cho

    2001-09-01

    In the model of quantum tunneling of domain walls in ferromagnets given by Chudnovsky et al., the crossover from quantum tunneling to classical hopping is investigated. Considering the periodical boundary condition of spatial coordinate, the type of transition depends critically on the length of ferromagnet along the Y-axis.

  16. Domain-wall excitations in the two-dimensional Ising spin glass

    Science.gov (United States)

    Khoshbakht, Hamid; Weigel, Martin

    2018-02-01

    The Ising spin glass in two dimensions exhibits rich behavior with subtle differences in the scaling for different coupling distributions. We use recently developed mappings to graph-theoretic problems together with highly efficient implementations of combinatorial optimization algorithms to determine exact ground states for systems on square lattices with up to 10 000 ×10 000 spins. While these mappings only work for planar graphs, for example for systems with periodic boundary conditions in at most one direction, we suggest here an iterative windowing technique that allows one to determine ground states for fully periodic samples up to sizes similar to those for the open-periodic case. Based on these techniques, a large number of disorder samples are used together with a careful finite-size scaling analysis to determine the stiffness exponents and domain-wall fractal dimensions with unprecedented accuracy, our best estimates being θ =-0.2793 (3 ) and df=1.273 19 (9 ) for Gaussian couplings. For bimodal disorder, a new uniform sampling algorithm allows us to study the domain-wall fractal dimension, finding df=1.279 (2 ) . Additionally, we also investigate the distributions of ground-state energies, of domain-wall energies, and domain-wall lengths.

  17. Breaking of chiral symmetry in vortex domain wall propagation in ferromagnetic nanotubes

    International Nuclear Information System (INIS)

    Otálora, J.A.; López-López, J.A.; Landeros, P.; Vargas, P.; Núñez, A.S.

    2013-01-01

    This paper is focused to the field-induced dynamics of vortex-like domain walls (VDWs) in magnetic nanotubes (MNTs). Based on a dissipative Lagrangian formalism that fully includes damping as well as exchange and dipole–dipole coupling, it is shown that VDW motion is very sensitive to the chirality, giving rise to a chiral asymmetry in the vortex wall propagation. As a consequence, the dynamics of the wall is fundamentally different to that of nanostripes and solid nanowires. Besides the well-known Walker breakdown that stands at the onset of the precessional wall motion, it is found an additional breakdown field (called here the chiral breakdown) that modifies the steady regime of VDWs. We also show outstanding VDWs dynamical properties at low applied fields, as low-field mobilities (∼10km/(sT)) and very short relaxation times (∼1ns), offering a reliable fast control of VDWs velocities (∼1000m/s at applied fields of 0.7 mT). - Highlights: • We model analytically the dynamics of vortex domain walls in magnetic nanotubes. • We fully include damping, exchange and dipole–dipole coupling. • The wall dynamics is fundamentally different to that of nanostripes. • We report and describe an extra dynamical instability, the Chiral Breakdown field. • We report outstanding dynamical properties at weak magnetic fields

  18. Dynamical scaling, domain-growth kinetics, and domain-wall shapes of quenched two-dimensional anisotropic XY models

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Praestgaard, Eigil

    1988-01-01

    obeys dynamical scaling and the shape of the dynamical scaling function pertaining to the structure factor is found to depend on P. Specifically, this function is described by a Porod-law behavior, q-ω, where ω increases with the wall softness. The kinetic exponent, which describes how the linear domain...... infinite to zero temperature as well as to nonzero temperatures below the ordering transition. The continuous nature of the spin variables causes the domain walls to be ‘‘soft’’ and characterized by a finite thickness. The steady-state thickness of the walls can be varied by a model parameter, P. At zero...... size varies with time, R(t)∼tn, is for both models at zero temperature determined to be n≃0.25, independent of P. At finite temperatures, the growth kinetics is found to cross over to the Lifshitz-Allen-Cahn law characterized by n≃0.50. The results support the idea of two separate zero...

  19. Domain morphology in ultrathin ferromagnetic films with perpendicular magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, B. [Department of Secondary Science and Mathematics Education, University of Mersin, Yenisehir Campus, 33169 Mersin (Turkey)]. E-mail: bengukaplan@yahoo.com

    2006-03-15

    We determine the minimal domain structure for the equilibrium thickness of stripes as well as for the minimal energy of the domain configuration in ultrathin films of ferromagnetically coupled spins, where the easy direction of magnetization is perpendicular to the film. It is found that the equilibrium thickness of stripes and walls depend on the exchange energy. The normalized anisotropy, f, depends on interplay between the magnetic and anisotropy energies and is almost independent of the exchange energy inside the wall. The results are compared with the experimental data for thin Ag/Fe/Ag (0 0 1) films and a good coincidence is obtained between both results.

  20. Stochastic Current-Driven Domain-Wall Motion Observed by X-Ray Microscopy

    Science.gov (United States)

    Meier, Guido

    2008-03-01

    Transmission x-ray microscopy can directly visualize the influence of a spin-polarized current on the magnetization of micro- and nanostructures. We investigate the stochastic motion of domain walls in curved wires [1] and the motion of vortices in squares [2]. To observe domain-wall motion pulses of nanosecond duration and high current density are send through permalloy wires and either move or deform the domain wall. The current pulses have nanosecond duration and a high current density of up to 1.0 10^12 A/m^2 and drive the wall either undisturbed, i.e. as a composite particle through the wire or causes structural changes of the magnetization. Repetitive pulse measurements reveal the stochastic nature of current induced domain-wall motion. From the experiments we estimate the ratio between the degree of nonadiabaticity and the Gilbert damping parameter indicating the importance of the nonadiabatic contribution to current driven domain-wall motion. To compare experimental results with theory the spin-torque transfer model of Zhang and Li [3] is implemented in the micromagnetic framework OOMMF [4]. The code is applied to determine the current-induced domain wall velocity using the material parameters of permalloy. The simulations support the interpretation of the experimental results. Sinusoidal high-density currents are applied to micrometer-sized permalloy squares containing ferromagnetic vortices. Spin-torque induced vortex gyration on the nanosecond timescale is observed. The phase of the gyration in structures with different chirality are compared to an analytical model and micromagnetic simulations, considering both alternating spin-polarized currents and the current's Oersted fields. This analysis reveals that spin-torque is the main source of motion. Supported by the DFG via SFB 668 and GK 1286 as well as by the U.S. DOE Contract No. DE-AC02-05-CH11231. References: [1] G. Meier, M. Bolte, R. Eiselt, U. Merkt, B. Krüger, D. Pfannkuche, D.-H. Kim, and P

  1. High-pressure oxygenation of thin-wall YBCO single-domain samples

    International Nuclear Information System (INIS)

    Chaud, X; Savchuk, Y; Sergienko, N; Prikhna, T; Diko, P

    2008-01-01

    The oxygen annealing of ReBCO bulk material, necessary to achieve superconducting properties, usually induces micro- and macro-cracks. This leads to a crack-assisted oxygenation process that allows oxygenating large bulk samples faster than single crystals. But excellent superconducting properties are cancelled by the poor mechanical ones. More progressive oxygenation strategy has been shown to reduce drastically the oxygenation cracks. The problem then arises to keep a reasonable annealing time. The concept of bulk Y123 single-domain samples with thin-wall geometry has been introduced to bypass the inherent limitation due to a slow oxygen diffusion rate. But it is not enough. The use of a high oxygen pressure (16 MPa) enables to speed up further the process. It introduces a displacement in the equilibrium phase diagram towards higher temperatures, i.e., higher diffusion rates, to achieve a given oxygen content in the material. Remarkable results were obtained by applying such a high pressure oxygen annealing process on thin-wall single-domain samples. The trapped field of 16 mm diameter Y123 thin-wall single-domain samples was doubled (0.6T vs 0.3T at 77K) using an annealing time twice shorter (about 3 days). The initial development was made on thin bars. The advantage of thin-wall geometry is that such an annealing can be applied directly to a much larger sample

  2. Tunneling decay of false domain walls: The silence of the lambs

    Energy Technology Data Exchange (ETDEWEB)

    Haberichter, Mareike, E-mail: M.Haberichter@kent.ac.uk [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); School of Mathematics, Statistics and Actuarial Science, University of Kent, Canterbury CT2 7NF (United Kingdom); MacKenzie, Richard, E-mail: richard.mackenzie@umontreal.ca; Ung, Yvan, E-mail: klingon-ecology@hotmail.com [Groupe de Physique des Particules, Département de Physique, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montreal, Québec H3C 3J7 (Canada); Paranjape, M. B., E-mail: paranj@lps.umontreal.ca [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Groupe de Physique des Particules, Département de Physique, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montreal, Québec H3C 3J7 (Canada); St. John’s College, University of Cambridge, Cambridge CB2 1TP (United Kingdom)

    2016-04-15

    We study the decay of “false” domain walls, that is, metastable states of the quantum theory where the true vacuum is trapped inside the wall with the false vacuum outside. We consider a theory with two scalar fields, a shepherd field and a field of sheep. The shepherd field serves to herd the solitons of the sheep field so that they are nicely bunched together. However, quantum tunnelling of the shepherd field releases the sheep to spread out uncontrollably. We show how to calculate the tunnelling amplitude for such a disintegration.

  3. Tunneling decay of false domain walls: The silence of the lambs

    International Nuclear Information System (INIS)

    Haberichter, Mareike; MacKenzie, Richard; Ung, Yvan; Paranjape, M. B.

    2016-01-01

    We study the decay of “false” domain walls, that is, metastable states of the quantum theory where the true vacuum is trapped inside the wall with the false vacuum outside. We consider a theory with two scalar fields, a shepherd field and a field of sheep. The shepherd field serves to herd the solitons of the sheep field so that they are nicely bunched together. However, quantum tunnelling of the shepherd field releases the sheep to spread out uncontrollably. We show how to calculate the tunnelling amplitude for such a disintegration.

  4. Optimized cobalt nanowires for domain wall manipulation imaged by in situ Lorentz microscopy

    International Nuclear Information System (INIS)

    Rodríguez, L. A.; Magén, C.; Snoeck, E.; Gatel, C.; Serrano-Ramón, L.

    2013-01-01

    Direct observation of domain wall (DW) nucleation and propagation in focused electron beam induced deposited Co nanowires as a function of their dimensions was carried out by Lorentz microscopy (LTEM) upon in situ application of magnetic field. Optimal dimensions favoring the unambiguous DW nucleation/propagation required for applications were found in 500-nm-wide and 13-nm-thick Co nanowires, with a maximum nucleation field and the largest gap between nucleation and propagation fields. The internal DW structures were resolved using the transport-of-intensity equation formalism in LTEM images and showed that the optimal nanowire dimensions correspond to the crossover between the nucleation of transverse and vortex walls.

  5. Determination of domain wall chirality using in situ Lorentz transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    Jordan J. Chess

    2017-05-01

    Full Text Available Controlling domain wall chirality is increasingly seen in non-centrosymmetric materials. Mapping chiral magnetic domains requires knowledge about all the vector components of the magnetization, which poses a problem for conventional Lorentz transmission electron microscopy (LTEM that is only sensitive to magnetic fields perpendicular to the electron beams direction of travel. The standard approach in LTEM for determining the third component of the magnetization is to tilt the sample to some angle and record a second image. This presents a problem for any domain structures that are stabilized by an applied external magnetic field (e.g. skyrmions, because the standard LTEM setup does not allow independent control of the angle of an applied magnetic field, and sample tilt angle. Here we show that applying a modified transport of intensity equation analysis to LTEM images collected during an applied field sweep, we can determine the domain wall chirality of labyrinth domains in a perpendicularly magnetized material, avoiding the need to tilt the sample.

  6. Evaluation of rumble stripes.

    Science.gov (United States)

    2010-01-01

    The objective of this study were to: a) monitor the initial installations of rumble stripes and b) evaluate the results of rumble stripe installations. : Ten rural, two-lane road locations were selected by the Kentucky Transportation Cabinet across t...

  7. Measurements of nanoscale domain wall flexing in a ferromagnetic thin film.

    Science.gov (United States)

    Balk, A L; Nowakowski, M E; Wilson, M J; Rench, D W; Schiffer, P; Awschalom, D D; Samarth, N

    2011-08-12

    We use the high spatial sensitivity of the anomalous Hall effect in the ferromagnetic semiconductor Ga(1-x)Mn(x)As, combined with the magneto-optical Kerr effect, to probe the nanoscale elastic flexing behavior of a single magnetic domain wall in a ferromagnetic thin film. Our technique allows position sensitive characterization of the pinning site density, which we estimate to be ∼10(14) cm(-3). Analysis of single site depinning events and their temperature dependence yields estimates of pinning site forces (10 pN range) as well as the thermal deactivation energy. Our data provide evidence for a much higher intrinsic domain wall mobility for flexing than previously observed in optically probed μm scale measurements.

  8. Localization and chiral symmetry in 2+1 flavor domain wall QCD

    Energy Technology Data Exchange (ETDEWEB)

    David J. Antonio; Kenneth C. Bowler; Peter A. Boyle; Norman H. Christ; Michael A. Clark; Saul D. Cohen; Chris Dawson; Alistair Hart; Balint Joó; Chulwoo Jung; Richard D. Kenway; Shu Li; Meifeng Lin; Robert D. Mawhinney; Christopher M. Maynard; Shigemi Ohta; Robert J. Tweedie; Azusa Yamaguchi

    2008-01-01

    We present results for the dependence of the residual mass of domain wall fermions (DWF) on the size of the fifth dimension and its relation to the density and localization properties of low-lying eigenvectors of the corresponding hermitian Wilson Dirac operator relevant to simulations of 2+1 flavor domain wall QCD. Using the DBW2 and Iwasaki gauge actions, we generate ensembles of configurations with a $16^3\\times 32$ space-time volume and an extent of 8 in the fifth dimension for the sea quarks. We demonstrate the existence of a regime where the degree of locality, the size of chiral symmetry breaking and the rate of topology change can be acceptable for inverse lattice spacings $a^{-1} \\ge 1.6$ GeV.

  9. Switching of ± 360° domain wall states in a nanoring by an azimuthal Oersted field.

    Science.gov (United States)

    Pradhan, N R; Licht, A S; Li, Y; Sun, Y; Tuominen, M T; Aidala, K E

    2011-12-02

    We demonstrate magnetic switching between two 360° domain wall vortex states in cobalt nanorings, which are candidate magnetic states for robust and low power magnetoresistive random access memory (MRAM) devices. These 360° domain wall (DW) or 'twisted onion' states can have clockwise or counterclockwise circulation, the two states for data storage. Reliable switching between the states is necessary for any realistic device. We accomplish this switching by applying a circular Oersted field created by passing current through a metal atomic force microscope tip placed at the center of the ring. After initializing in an onion state, we rotate the DWs to one side of the ring by passing a current through the center, and can switch between the two twisted states by reversing the current, causing the DWs to split and meet again on the opposite side of the ring. A larger current will annihilate the DWs and create a perfect vortex state in the rings.

  10. Current-driven domain wall ratchet in a nanomagnet with functionally graded Dzyaloshinskii-Moriya interaction

    Science.gov (United States)

    Yershov, Kostiantyn V.; Sheka, Denis D.; Kravchuk, Volodymyr P.; Gaididei, Yuri; Saxena, Avadh

    We develop a concept of functionally graded Dzyaloshinskii-Moriya interaction, which provides novel ways of efficient control of the magnetization dynamics. Using this approach we realize the ratchet motion of the domain wall in a magnetic nanowire driven by spin polarized current with potential applications in magnetic devices such as race-track memory and magnetic logical devices. By engineering the spatial profile of Dzyaloshinskii-Moriya parameters we provide a unidirectional motion of the domain wall along the wire. We base our study on phenomenological Landau-Lifshitz-Gilbert equations using a collective variable approach. In effective equations of motion the functionally graded Dzyaloshinskii-Moriya interaction appears as a driving force, which can either suppress the action of the pumping by the current or can reinforce it. All analytical predictions are well confirmed by numerical simulations.

  11. Logic circuit prototypes for three-terminal magnetic tunnel junctions with mobile domain walls.

    Science.gov (United States)

    Currivan-Incorvia, J A; Siddiqui, S; Dutta, S; Evarts, E R; Zhang, J; Bono, D; Ross, C A; Baldo, M A

    2016-01-12

    Spintronic computing promises superior energy efficiency and nonvolatility compared to conventional field-effect transistor logic. But, it has proven difficult to realize spintronic circuits with a versatile, scalable device design that is adaptable to emerging material physics. Here we present prototypes of a logic device that encode information in the position of a magnetic domain wall in a ferromagnetic wire. We show that a single three-terminal device can perform inverter and buffer operations. We demonstrate one device can drive two subsequent gates and logic propagation in a circuit of three inverters. This prototype demonstration shows that magnetic domain wall logic devices have the necessary characteristics for future computing, including nonlinearity, gain, cascadability, and room temperature operation.

  12. Perterbative O(asa) matching in static heavy and domain-wall light quark system

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa,T.

    2008-07-14

    We discuss the perturbative O(a{sub s}a) matching in the static heavy and domain-wall light quark system. The gluon action is the Iwasaki action and the link smearing is performed in the static heavy action. The chiral symmetry of the light quark realized by using the domain-wall fermion formulation does not prohibit the mixing of the operators at O(a). The application of O(a) improvement to the actual data shows that the B meson decay constant f{sub B}, the matrix elements M{sub B} and the B parameter B{sub B} have non-negligible effects, while the effect on the SU(3) breaking ratio {zeta} is small.

  13. Strain-controlled magnetic domain wall propagation in hybrid piezoelectric/ferromagnetic structures.

    Science.gov (United States)

    Lei, Na; Devolder, Thibaut; Agnus, Guillaume; Aubert, Pascal; Daniel, Laurent; Kim, Joo-Von; Zhao, Weisheng; Trypiniotis, Theodossis; Cowburn, Russell P; Chappert, Claude; Ravelosona, Dafiné; Lecoeur, Philippe

    2013-01-01

    The control of magnetic order in nanoscale devices underpins many proposals for integrating spintronics concepts into conventional electronics. A key challenge lies in finding an energy-efficient means of control, as power dissipation remains an important factor limiting future miniaturization of integrated circuits. One promising approach involves magnetoelectric coupling in magnetostrictive/piezoelectric systems, where induced strains can bear directly on the magnetic anisotropy. While such processes have been demonstrated in several multiferroic heterostructures, the incorporation of such complex materials into practical geometries has been lacking. Here we demonstrate the possibility of generating sizeable anisotropy changes, through induced strains driven by applied electric fields, in hybrid piezoelectric/spin-valve nanowires. By combining magneto-optical Kerr effect and magnetoresistance measurements, we show that domain wall propagation fields can be doubled under locally applied strains. These results highlight the prospect of constructing low-power domain wall gates for magnetic logic devices.

  14. Enhanced Worldvolume Supersymmetry and Intersecting Domain Walls in N=1 SQCD

    CERN Document Server

    Shifman, M; Vainshtein, A I

    2004-01-01

    We study the worldvolume dynamics of BPS domain walls in N=1 SQCD with N_f=N flavors, and exhibit an enhancement of supersymmetry for the reduced moduli space associated with broken flavor symmetries. We provide an explicit construction of the worldvolume superalgebra which corresponds to an N=2 Kahler sigma model in 2+1D deformed by a potential, given by the norm squared of a U(1) Killing vector, resulting from the flavor symmetries broken by unequal quark masses. This framework leads to a worldvolume description of novel two-wall junction configurations, which are 1/4-BPS objects, but nonetheless preserve two supercharges when viewed as kinks on the wall worldvolume.

  15. Inertial displacement of a domain wall excited by ultra-short circularly polarized laser pulses

    Czech Academy of Sciences Publication Activity Database

    Janda, Tomáš; Roy, P.E.; Otxoa, R.M.; Šobáň, Zbyněk; Ramsay, A.; Irvine, A.C.; Trojánek, F.; Surynek, M.; Campion, R. P.; Gallagher, B. L.; Němec, P.; Jungwirth, Tomáš; Wunderlich, Joerg

    2017-01-01

    Roč. 8, May (2017), 1-7, č. článku 15226. ISSN 2041-1723 R&D Projects: GA MŠk LM2015087; GA ČR GB14-37427G EU Projects: European Commission(XE) 610115 - SC2 Institutional support: RVO:68378271 Keywords : spintronics * domain walls Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 12.124, year: 2016

  16. On-Chip Manipulation of Protein-Coated Magnetic Beads via Domain-Wall Conduits

    DEFF Research Database (Denmark)

    Donolato, Marco; Vavassori, Paolo; Gobbi, Marco

    2010-01-01

    Geometrically constrained magnetic domain walls (DWs) in magnetic nanowires can be manipulated at the nanometer scale. The inhomogeneous magnetic stray field generated by a DW can capture a magnetic nanoparticle in solution. On-chip nanomanipulation of individual magnetic beads coated with proteins...... is demonstrated through the motion of geometrically constrained DWs in specially designed magnetic nanoconduits fully integrated in a lab-on-a-chip platform....

  17. Magneto-transport measurements of domain wall propagation in individual multi segmented cylindrical nanowires

    KAUST Repository

    Mohammed, Hanan

    2016-03-01

    Magnetotransport measurements were performed on multisegmented Co/Ni nanowires fabricated by template-assisted electrodeposition. Individual nanowires were isolated and electrodes patterned to study their magnetization reversal process. The magnetoresistance reversal curve of the multisegmented nanowire exhibits a step in the switching field. Micromagnetic simulations of the magnetization reversal process are in agreement with the experimental findings and attribute the step at the switching field to the pinning of a domain wall at the interface of the Co/Ni nanowire.

  18. High antiferromagnetic domain wall velocity induced by Néel spin-orbit torques

    Czech Academy of Sciences Publication Activity Database

    Gomonay, O.; Jungwirth, Tomáš; Sinova, Jairo

    2016-01-01

    Roč. 117, č. 1 (2016), 1-5, č. článku 017202. ISSN 0031-9007 R&D Projects: GA MŠk(CZ) LM2011026; GA ČR GB14-37427G EU Projects: European Commission(XE) 268066 - 0MSPIN Institutional support: RVO:68378271 Keywords : spintronics * domain walls * antiferromagnets Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 8.462, year: 2016

  19. The Kaon B-parameter from Two-Flavour Dynamical Domain Wall Fermions

    International Nuclear Information System (INIS)

    Dawson, C.

    2005-01-01

    We report on the calculation of the kaon B-parameter using two dynamical flavours of domain wall fermions. Our analysis is based on three ensembles of configurations, each consisting of about 5,000 HMC trajectories, with a lattice spacing of approximately 1.7 GeV for 16 3 x32 lattices; dynamical quark masses range from approximately the strange quark mass to half of that. Both degenerate and non-degenerate quark masses are used for the kaons

  20. Identification of microscopic domain wall motion from temperature dependence of nonlinear dielectric response.

    Czech Academy of Sciences Publication Activity Database

    Mokrý, Pavel; Sluka, T.

    2017-01-01

    Roč. 110, č. 16 (2017), č. článku 162906. ISSN 0003-6951 R&D Projects: GA ČR(CZ) GA14-32228S Institutional support: RVO:61389021 Keywords : microscopic domain wall * electric fields * temperature dependence Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Electrical and electronic engineering Impact factor: 3.411, year: 2016 http://dx.doi.org/10.1063/1.4981874

  1. The Cosmological Constant and Domain Walls in Orientifold Field Theories and N=1 Gluodynamics

    CERN Document Server

    Armoni, Adi

    2003-01-01

    We discuss domain walls and vacuum energy density (cosmological constant) in N=1 gluodynamics and in non-supersymmetric large N orientifold field theories which have been recently shown to be planar equivalent (in the boson sector) to N=1 gluodynamics. A relation between the vanishing force between two parallel walls and vanishing cosmological constant is pointed out. This relation may explain why the cosmological constant vanishes in the orientifold field theory at leading order although the hadronic spectrum of this theory does not contain fermions in the limit N-->infinity. The cancellation is among even and odd parity bosonic contributions, due to NS-NS and R-R cancellations in the annulus amplitude of the underlying string theory. We use the open-closed string channel duality to describe interaction between the domain walls which is interpreted as the exchange of composite ``dilatons'' and ``axions'' coupled to the walls. Finally, we study some planar equivalent pairs in which both theories in the parent...

  2. Exploring Cell Wall Composition and Modifications During the Development of the Gynoecium Medial Domain in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Humberto Herrera-Ubaldo

    2018-04-01

    Full Text Available In Arabidopsis, the gynoecium, the inner whorl of the flower, is the female reproductive part. Many tissues important for fertilization such as the stigma, style, transmitting tract, placenta, ovules, and septum, comprising the medial domain, arise from the carpel margin meristem. During gynoecium development, septum fusion occurs and tissues form continuously to prepare for a successful pollination and fertilization. During gynoecium development, cell wall modifications take place and one of the most important is the formation of the transmitting tract, having a great impact on reproductive competence because it facilitates pollen tube growth and movement through the ovary. In this study, using a combination of classical staining methods, fluorescent dyes, and indirect immunolocalization, we analyzed cell wall composition and modifications accompanying medial domain formation during gynoecium development. We detected coordinated changes in polysaccharide distribution through time, cell wall modifications preceding the formation of the transmitting tract, mucosubstances increase during transmitting tract formation, and a decrease of mannan distribution. Furthermore, we also detected changes in lipid distribution during septum fusion. Proper cell wall composition and modifications are important for postgenital fusion of the carpel (septum fusion and transmitting tract formation, because these tissues affect plant reproductive competence.

  3. Magnetic scanning gate microscopy of a domain wall nanosensor using microparticle probe

    Energy Technology Data Exchange (ETDEWEB)

    Corte-León, H., E-mail: hector.corte@npl.co.uk [National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Royal Holloway University of London, Egham TW20 0EX (United Kingdom); Gribkov, B. [National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Krzysteczko, P. [Physikalisch-Technische Bundesanstalt, Braunschweig D-38116 (Germany); Marchi, F.; Motte, J.-F. [University of Grenoble Alpes, Inst. NEEL, Grenoble F-38042 (France); CNRS, Inst. NEEL, Grenoble F-38042 (France); Schumacher, H.W. [Physikalisch-Technische Bundesanstalt, Braunschweig D-38116 (Germany); Antonov, V. [Royal Holloway University of London, Egham TW20 0EX (United Kingdom); Kazakova, O. [National Physical Laboratory, Teddington TW11 0LW (United Kingdom)

    2016-02-15

    We apply the magnetic scanning gate microscopy (SGM) technique to study the interaction between a magnetic bead (MB) and a domain wall (DW) trapped in an L-shaped magnetic nanostructure. Magnetic SGM is performed using a custom-made probe, comprising a hard magnetic NdFeB bead of diameter 1.6 µm attached to a standard silicon tip. The MB–DW interaction is detected by measuring changes in the electrical resistance of the device as a function of the tip position. By scanning at different heights, we create a 3D map of the MB–DW interaction and extract the sensing volume for different widths of the nanostructure's arms. It is shown that for 50 nm wide devices the sensing volume is a cone of 880 nm in diameter by 1.4 µm in height, and reduces down to 800 nm in height for 100 nm devices with almost no change in its diameter. - Highlights: • AFM tips with a magnetic bead attached used to test interaction with domain wall. • Domain wall inside a nanostructure affect the electrical resistance. • Recording electrical resistance while scanning with modified AFM probe. • Change of resistance as a function of the position of the magnetic bead. • This allows comparing different devices in a reproducible and controllable way.

  4. Logic and memory concepts for all-magnetic computing based on transverse domain walls

    Science.gov (United States)

    Vandermeulen, J.; Van de Wiele, B.; Dupré, L.; Van Waeyenberge, B.

    2015-06-01

    We introduce a non-volatile digital logic and memory concept in which the binary data is stored in the transverse magnetic domain walls present in in-plane magnetized nanowires with sufficiently small cross sectional dimensions. We assign the digital bit to the two possible orientations of the transverse domain wall. Numerical proofs-of-concept are presented for a NOT-, AND- and OR-gate, a FAN-out as well as a reading and writing device. Contrary to the chirality based vortex domain wall logic gates introduced in Omari and Hayward (2014 Phys. Rev. Appl. 2 044001), the presented concepts remain applicable when miniaturized and are driven by electrical currents, making the technology compatible with the in-plane racetrack memory concept. The individual devices can be easily combined to logic networks working with clock speeds that scale linearly with decreasing design dimensions. This opens opportunities to an all-magnetic computing technology where the digital data is stored and processed under the same magnetic representation.

  5. Logic and memory concepts for all-magnetic computing based on transverse domain walls

    International Nuclear Information System (INIS)

    Vandermeulen, J; Van de Wiele, B; Dupré, L; Van Waeyenberge, B

    2015-01-01

    We introduce a non-volatile digital logic and memory concept in which the binary data is stored in the transverse magnetic domain walls present in in-plane magnetized nanowires with sufficiently small cross sectional dimensions. We assign the digital bit to the two possible orientations of the transverse domain wall. Numerical proofs-of-concept are presented for a NOT-, AND- and OR-gate, a FAN-out as well as a reading and writing device. Contrary to the chirality based vortex domain wall logic gates introduced in Omari and Hayward (2014 Phys. Rev. Appl. 2 044001), the presented concepts remain applicable when miniaturized and are driven by electrical currents, making the technology compatible with the in-plane racetrack memory concept. The individual devices can be easily combined to logic networks working with clock speeds that scale linearly with decreasing design dimensions. This opens opportunities to an all-magnetic computing technology where the digital data is stored and processed under the same magnetic representation. (paper)

  6. Transmission XMCD-PEEM imaging of an engineered vertical FEBID cobalt nanowire with a domain wall

    Science.gov (United States)

    Wartelle, A.; Pablo-Navarro, J.; Staňo, M.; Bochmann, S.; Pairis, S.; Rioult, M.; Thirion, C.; Belkhou, R.; de Teresa, J. M.; Magén, C.; Fruchart, O.

    2018-01-01

    Using focused electron-beam-induced deposition, we fabricate a vertical, platinum-coated cobalt nanowire with a controlled three-dimensional structure. The latter is engineered to feature bends along the height: these are used as pinning sites for domain walls, which are obtained at remanence after saturation of the nanostructure in a horizontally applied magnetic field. The presence of domain walls is investigated using x-ray magnetic circular dichroism (XMCD) coupled to photoemission electron microscopy (PEEM). The vertical geometry of our sample combined with the low incidence of the x-ray beam produce an extended wire shadow which we use to recover the wire’s magnetic configuration. In this transmission configuration, the whole sample volume is probed, thus circumventing the limitation of PEEM to surfaces. This article reports on the first study of magnetic nanostructures standing perpendicular to the substrate with XMCD-PEEM. The use of this technique in shadow mode enabled us to confirm the presence of a domain wall without direct imaging of the nanowire.

  7. Domain Wall Dynamics Driven by a Localized Injection of a Spin-Polarized Current

    Science.gov (United States)

    Finocchio, Giovanni; Maugeri, Natale; Torres, Luis; Azzerboni, Bruno

    2010-06-01

    This paper introduces an oscillator scheme based on the oscillations of magnetic domain walls due to spin-polarized currents, where the current is injected perpendicular to the sample plane in a localized part of a nanowire. Depending on the geometrical and physical characteristic of the system, we identify two different dynamical regimes (auto-oscillations) when an out-of-plane external field is applied. The first regime is characterized by nucleation of domain walls (DWs) below the current injection site and the propagation of those up to the end of the nanowire, we also found an oscillation frequency larger than 5GHz with a linear dependence on the applied current density. This simple system can be used as a tuneable steady-state domain wall oscillator. In the second dynamical regime, we observe the nucleation of two DWs which propagate back and forth in the nanowire with a sub-GHz oscillation frequency. The micromagnetic spectral mapping technique shows the spatial distribution of the output power is localized symmetrically in the nanowire. We suggest that this configuration can be used as micromagnetic transformer to decouple electrically two different circuits.

  8. Steady-state configurations of Dzyaloshinskii domain walls driven by field and current

    International Nuclear Information System (INIS)

    Sánchez-Tejerina, L.; Alejos, O.; Martínez, E.

    2017-01-01

    The dynamics of Dzyaloshinskii domain walls (DDW) in ultrathin ferromagnetic strips with perpendicular magnetic anisotropy, for different values of both perpendicular field and longitudinal current excitation associated to the Spin-Hall effect, has been studied, taking into account different values of the interfacial Dzyaloshinskii-Moriya interaction (DMI). This study has been carried out with the help of the q-Φ one-dimensional model and micromagnetic simulations. We have found that Walker breakdown may be avoided by applying a certain threshold current, even though the inverse effect is also possible. We have also found that, for particular values of field and current, the magnetization within the DDW experiences an abrupt change of orientation, which provokes a change on the contribution of current to the terminal DDW velocity. This effect disappears for sufficiently strong DMI, as it is expected from the model. - Highlights: • Steady-state configurations of Dzyaloshinskii domain walls driven by field and current have been reported. • Field-like torques and Slonczewskii-like torques due to spin-orbit interactions have been considered. • The response is associated with the rotation of the domain wall inner magnetization. • An asymmetric behavior arising from the existence of degenerate states is shown. • The asymmetry results in different travelled distances and/or terminal speeds.

  9. Steady-state configurations of Dzyaloshinskii domain walls driven by field and current

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Tejerina, L., E-mail: luis.st@ee.uva.es [Departamento de Electricidad y Electrónica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid (Spain); Departamento de Física Aplicada, Facultad de Ciencias, Universidad de Salamanca, 37011 Salamanca (Spain); Alejos, O. [Departamento de Electricidad y Electrónica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid (Spain); Martínez, E. [Departamento de Física Aplicada, Facultad de Ciencias, Universidad de Salamanca, 37011 Salamanca (Spain)

    2017-02-01

    The dynamics of Dzyaloshinskii domain walls (DDW) in ultrathin ferromagnetic strips with perpendicular magnetic anisotropy, for different values of both perpendicular field and longitudinal current excitation associated to the Spin-Hall effect, has been studied, taking into account different values of the interfacial Dzyaloshinskii-Moriya interaction (DMI). This study has been carried out with the help of the q-Φ one-dimensional model and micromagnetic simulations. We have found that Walker breakdown may be avoided by applying a certain threshold current, even though the inverse effect is also possible. We have also found that, for particular values of field and current, the magnetization within the DDW experiences an abrupt change of orientation, which provokes a change on the contribution of current to the terminal DDW velocity. This effect disappears for sufficiently strong DMI, as it is expected from the model. - Highlights: • Steady-state configurations of Dzyaloshinskii domain walls driven by field and current have been reported. • Field-like torques and Slonczewskii-like torques due to spin-orbit interactions have been considered. • The response is associated with the rotation of the domain wall inner magnetization. • An asymmetric behavior arising from the existence of degenerate states is shown. • The asymmetry results in different travelled distances and/or terminal speeds.

  10. Three-dimensional, time-resolved profiling of ferroelectric domain wall dynamics by spectral-domain optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Haussmann, Alexander; Schmidt, Sebastian; Wehmeier, Lukas; Eng, Lukas M. [Technische Universitaet Dresden, Institute of Applied Physics and Center for Advancing Electronics Dresden (cfaed), Dresden (Germany); Kirsten, Lars; Cimalla, Peter; Koch, Edmund [Technische Universitaet Dresden, Faculty of Medicine Carl Gustav Carus, Anesthesiology and Intensive Care Medicine, Clinical Sensoring and Monitoring, Dresden (Germany)

    2017-08-15

    We apply here spectral-domain optical coherence tomography (SD-OCT) for the precise detection and temporal tracking of ferroelectric domain walls (DWs) in magnesium-doped periodically poled lithium niobate (Mg:PPLN). We reproducibly map static DWs at an axial (depth) resolution down to ∝ 0.6 μm, being located up to 0.5 mm well inside the single crystalline Mg:PPLN sample. We show that a full 3-dimensional (3D) reconstruction of the DW geometry is possible from the collected data, when applying a special algorithm that accounts for the nonlinear optical dispersion of the material. Our OCT investigation provides valuable reference information on the DWs' polarization charge distribution, which is known to be the key to the electrical conductivity of ferroelectric DWs in such systems. Hence, we carefully analyze the SD-OCT signal dependence both when varying the direction of incident polarization, and when applying electrical fields along the polar axis. Surprisingly, the large backreflection intensities recorded under extraordinary polarization are not affected by any electrical field, at least for field strengths below the switching threshold, while no significant signals above noise floor are detected under ordinary polarization. Finally, we employed the high-speed SD-OCT setup for the real-time DW tracking upon ferroelectric domain switching under high external fields. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Domain Walls, near-BPS Bubbles and Probabilities in the Landscape

    Energy Technology Data Exchange (ETDEWEB)

    Ceresole, Anna; /INFN, Turin /Turin U.; Dall' Agata, Gianguido; /CERN; Giryavets, Alexander; Kallosh, Renata; Linde, Andrei; /Stanford U., Phys. Dept.

    2006-06-27

    We develop a theory of static BPS domain walls in stringy landscape and present a large family of BPS walls interpolating between different supersymmetric vacua. Examples include KKLT models, STU models, type IIB multiple flux vacua, and models with several Minkowski and AdS vacua. After the uplifting, some of the vacua become dS, whereas some others remain AdS. The near-BPS walls separating these vacua may be seen as bubble walls in the theory of vacuum decay. As an outcome of our investigation of the BPS walls, we found that the decay rate of dS vacua to a collapsing space with a negative vacuum energy can be quite large. The parts of space that experience a decay to a collapsing space, or to a Minkowski vacuum, never return back to dS space. The channels of irreversible vacuum decay serve as sinks for the probability flow. The existence of such sinks is a distinguishing feature of the landscape. We show that it strongly affects the probability distributions in string cosmology.

  12. Quantum Interference Control of Ballistic Magneto- resistance in a Magnetic Nanowire Containing Two Atomic- Size Domain Walls

    Directory of Open Access Journals (Sweden)

    V. Fallahi

    2012-06-01

    Full Text Available The magnetoresistance of a one-dimensional electron gas in a metallic ferromagnetic nanowire containing two atomic-size domain walls has been investigated in the presence of spin-orbit interaction. The magnetoresistance is calculated in the ballistic regime, within the Landauer-Büttiker formalism. It has been demonstrated that the conductance of a magnetic nanowire with double domain walls can be controlled through the domain walls separation. Also, we have represented another alternative way that enables us to handle easily the magnetoresistance of such a system as well as its conductance by utilizing the Rashba-type spin-orbit interaction induced by the external gates.

  13. Formation of self-organized domain structures with charged domain walls in lithium niobate with surface layer modified by proton exchange

    Science.gov (United States)

    Shur, V. Ya.; Akhmatkhanov, A. R.; Chuvakova, M. A.; Dolbilov, M. A.; Zelenovskiy, P. S.; Lobov, A. I.

    2017-03-01

    We have studied the self-organized dendrite domain structures appeared as a result of polarization reversal in the uniform field in lithium niobate single crystals with the artificial surface layer created by proton exchange. We have revealed the self-organized sub-micron scale dendrite domain patterns consisting of domain stripes oriented along the X crystallographic directions separated by arrays of dashed residual domains at the surface by scanning probe microscopy. Raman confocal microscopy allowed visualizing the quasi-regular dendrite domain structures with similar geometry in the vicinity of both polar surfaces. The depth of the structure was about 20 μm for Z+ polar surface and 70 μm for Z- one. According to the proposed mechanism, the dendrite structure formation at the surface was related to the ineffective screening of the residual depolarization field. The computer simulation of the structure formation based on the cellular automata model with probabilistic switching rule proved the eligibility of the proposed scheme, the simulated dendrite domain patterns at various depths being similar to the experimental ones.

  14. Exploding Stars and Stripes

    Science.gov (United States)

    2011-03-01

    The discovery of a pattern of X-ray "stripes" in the remains of an exploded star may provide the first direct evidence that a cosmic event can accelerate particles to energies a hundred times higher than achieved by the most powerful particle accelerator on Earth. This result comes from a very long observation of the Tycho supernova remnant with NASA's Chandra X-ray Observatory. It could explain how some of the extremely energetic particles bombarding the Earth, called cosmic rays, are produced. "We've seen lots of intriguing structures in supernova remnants, but we've never seen stripes before," said Kristoffer Eriksen, a postdoctoral researcher at Rutgers University who led the study. "This made us think very hard about what's happening in the blast wave of this powerful explosion." This latest study from Chandra provides support for a theory about how magnetic fields can be dramatically amplified in such blast waves. In this theory, the magnetic fields become highly tangled and the motions of the particles very turbulent near the expanding supernova shock wave at the front edge of the supernova remnant. High-energy charged particles can bounce back and forth across the shock wave repeatedly, gaining energy with each crossing. Theoretical models of the motion of the most energetic particles -- which are mostly protons -- are predicted to leave a messy network of holes and dense walls corresponding to weak and strong regions of magnetic fields, respectively. The X-ray stripes discovered by the Chandra researchers are thought to be regions where the turbulence is greater and the magnetic fields more tangled than surrounding areas, and may be the walls predicted by the theory. Electrons become trapped in these regions and emit X-rays as they spiral around the magnetic field lines. However, the regular and almost periodic pattern of the X-ray stripes was not predicted by the theory. "It was a big surprise to find such a neatly arranged set of stripes," said co

  15. Role of spin diffusion in current-induced domain wall motion for disordered ferromagnets

    KAUST Repository

    Akosa, Collins Ashu

    2015-03-12

    Current-induced spin transfer torque and magnetization dynamics in the presence of spin diffusion in disordered magnetic textures is studied theoretically. We demonstrate using tight-binding calculations that weak, spin-conserving impurity scattering dramatically enhances the nonadiabaticity. To further explore this mechanism, a phenomenological drift-diffusion model for incoherent spin transport is investigated. We show that incoherent spin diffusion indeed produces an additional spatially dependent torque of the form ∼∇2[m×(u⋅∇)m]+ξ∇2[(u⋅∇)m], where m is the local magnetization direction, u is the direction of injected current, and ξ is a parameter characterizing the spin dynamics (precession, dephasing, and spin-flip). This torque, which scales as the inverse square of the domain wall width, only weakly enhances the longitudinal velocity of a transverse domain wall but significantly enhances the transverse velocity of vortex walls. The spatial-dependent spin transfer torque uncovered in this study is expected to have significant impact on the current-driven motion of abrupt two-dimensional textures such as vortices, skyrmions, and merons.

  16. Investigation of domain walls in PPLN by confocal raman microscopy and PCA analysis

    Science.gov (United States)

    Shur, Vladimir Ya.; Zelenovskiy, Pavel; Bourson, Patrice

    2017-07-01

    Confocal Raman microscopy (CRM) is a powerful tool for investigation of ferroelectric domains. Mechanical stresses and electric fields existed in the vicinity of neutral and charged domain walls modify frequency, intensity and width of spectral lines [1], thus allowing to visualize micro- and nanodomain structures both at the surface and in the bulk of the crystal [2,3]. Stresses and fields are naturally coupled in ferroelectrics due to inverse piezoelectric effect and hardly can be separated in Raman spectra. PCA is a powerful statistical method for analysis of large data matrix providing a set of orthogonal variables, called principal components (PCs). PCA is widely used for classification of experimental data, for example, in crystallization experiments, for detection of small amounts of components in solid mixtures etc. [4,5]. In Raman spectroscopy PCA was applied for analysis of phase transitions and provided critical pressure with good accuracy [6]. In the present work we for the first time applied Principal Component Analysis (PCA) method for analysis of Raman spectra measured in periodically poled lithium niobate (PPLN). We found that principal components demonstrate different sensitivity to mechanical stresses and electric fields in the vicinity of the domain walls. This allowed us to separately visualize spatial distribution of fields and electric fields at the surface and in the bulk of PPLN.

  17. Control of domain wall pinning by localised focused Ga + ion irradiation on Au capped NiFe nanowires

    International Nuclear Information System (INIS)

    Burn, D. M.; Atkinson, D.

    2014-01-01

    Understanding domain wall pinning and propagation in nanowires are important for future spintronics and nanoparticle manipulation technologies. Here, the effects of microscopic local modification of the magnetic properties, induced by focused-ion-beam intermixing, in NiFe/Au bilayer nanowires on the pinning behavior of domain walls was investigated. The effects of irradiation dose and the length of the irradiated features were investigated experimentally. The results are considered in the context of detailed quasi-static micromagnetic simulations, where the ion-induced modification was represented as a local reduction of the saturation magnetization. Simulations show that domain wall pinning behavior depends on the magnitude of the magnetization change, the length of the modified region, and the domain wall structure. Comparative analysis indicates that reduced saturation magnetisation is not solely responsible for the experimentally observed pinning behavior.

  18. Brownian motion and entropic torque driven motion of domain walls in antiferromagnets

    Science.gov (United States)

    Yan, Zhengren; Chen, Zhiyuan; Qin, Minghui; Lu, Xubing; Gao, Xingsen; Liu, Junming

    2018-02-01

    We study the spin dynamics in antiferromagnetic nanowire under an applied temperature gradient using micromagnetic simulations on a classical spin model with a uniaxial anisotropy. The entropic torque driven domain-wall motion and the Brownian motion are discussed in detail, and their competition determines the antiferromagnetic wall motion towards the hotter or colder region. Furthermore, the spin dynamics in an antiferromagnet can be well tuned by the anisotropy and the temperature gradient. Thus, this paper not only strengthens the main conclusions obtained in earlier works [Kim et al., Phys. Rev. B 92, 020402(R) (2015), 10.1103/PhysRevB.92.020402; Selzer et al., Phys. Rev. Lett. 117, 107201 (2016), 10.1103/PhysRevLett.117.107201], but more importantly gives the concrete conditions under which these conclusions apply, respectively. Our results may provide useful information on the antiferromagnetic spintronics for future experiments and storage device design.

  19. Direct observation of current-induced motion of a 3D vortex domain wall in cylindrical nanowires

    KAUST Repository

    Ivanov, Yurii P.

    2017-05-08

    The current-induced dynamics of 3D magnetic vortex domain walls in cylindrical Co/Ni nanowires are revealed experimentally using Lorentz microscopy and theoretically using micromagnetic simulations. We demonstrate that a spin-polarized electric current can control the reversible motion of 3D vortex domain walls, which travel with a velocity of a few hundred meters per second. This finding is a key step in establishing fast, high-density memory devices based on vertical arrays of cylindrical magnetic nanowires.

  20. Interplay between collective pinning and artificial defects on domain wall propagation in Co/Pt multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Rodriguez, G; Hierro-Rodriguez, A; Perez-Junquera, A; Montenegro, N; Alameda, J M; Velez, M [Dept. Fisica, Universidad de Oviedo-CINN, 33007 Oviedo (Spain); Menendez, J L [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN). Principado de Asturias-Consejo Superior de Investigaciones Cientificas (CSIC)-Univ. Oviedo -UO, Parque Tecnologico de Asturias, 33428 Llanera (Spain); Ravelosona, D, E-mail: mvelez@uniovi.e [Institut d' Electronique Fondamentale, UMR CNRS 8622, Univ. Paris Sud, 91405 Orsay Cedex (France)

    2010-08-04

    The interplay between collective pinning on intrinsic structural defects and artificial pinning at a patterned hole is studied in magnetic multilayers with perpendicular anisotropy. The pinning strength of a patterned hole is measured through its efficiency to stop domain wall (DW) propagation into a consecutive unpatterned nanowire section (using antisymmetric magnetoresistance to detect the direction of DW propagation) whereas collective pinning is characterized by the field dependence of DW velocity. Close to room temperature, collective pinning becomes weaker than artificial pinning so that pinning at the hole compensates nucleation-pad geometry, blocking DW propagation across the nanowire.

  1. Flavor connections and neutrino mass hierarchy in variant invisible axion models without domain wall problem

    International Nuclear Information System (INIS)

    Geng, C.Q.; Ng, J.N.

    1988-08-01

    New types of invisible axion model based on the recent variant axion models are presented. They belong to the N=1 type model and hence are free of domain wall problems. The Peccei-Quinn symmetry transformations are not totally generation and flavor blind, which may help in understanding the small values of electron and u-quark and large t-quark masses. The light neutrino mass pattern in the two Higgs singlet models can have a very different hierarchy that differs from the other type invisible axion model. (Author) (25 refs.)

  2. General purpose graphics-processing-unit implementation of cosmological domain wall network evolution.

    Science.gov (United States)

    Correia, J R C C C; Martins, C J A P

    2017-10-01

    Topological defects unavoidably form at symmetry breaking phase transitions in the early universe. To probe the parameter space of theoretical models and set tighter experimental constraints (exploiting the recent advances in astrophysical observations), one requires more and more demanding simulations, and therefore more hardware resources and computation time. Improving the speed and efficiency of existing codes is essential. Here we present a general purpose graphics-processing-unit implementation of the canonical Press-Ryden-Spergel algorithm for the evolution of cosmological domain wall networks. This is ported to the Open Computing Language standard, and as a consequence significant speedups are achieved both in two-dimensional (2D) and 3D simulations.

  3. Nucleon structure in the chiral regime with domain wall fermions on an improved staggered sea

    International Nuclear Information System (INIS)

    R.G. Edwards; G. Fleming; Ph. Hagler; J.W. Negele; K. Orginos; A.V. Pochinsky; D.B. Renner; D.G. Richards; W. Schroers

    2006-01-01

    Moments of unpolarized, helicity, and transversity distributions, electromagnetic form factors, and generalized form factors of the nucleon are presented from a preliminary analysis of lattice results using pion masses down to 359 MeV. The twist two matrix elements are calculated using a mixed action of domain wall valence quarks and asqtad staggered sea quarks and are renormalized perturbatively. Several observables are extrapolated to the physical limit using chiral perturbation theory. Results are compared with experimental moments of quark distributions and electromagnetic form factors and phenomenologically determined generalized form factors, and the implications on the transverse structure and spin content of the nucleon are discussed

  4. General purpose graphics-processing-unit implementation of cosmological domain wall network evolution

    Science.gov (United States)

    Correia, J. R. C. C. C.; Martins, C. J. A. P.

    2017-10-01

    Topological defects unavoidably form at symmetry breaking phase transitions in the early universe. To probe the parameter space of theoretical models and set tighter experimental constraints (exploiting the recent advances in astrophysical observations), one requires more and more demanding simulations, and therefore more hardware resources and computation time. Improving the speed and efficiency of existing codes is essential. Here we present a general purpose graphics-processing-unit implementation of the canonical Press-Ryden-Spergel algorithm for the evolution of cosmological domain wall networks. This is ported to the Open Computing Language standard, and as a consequence significant speedups are achieved both in two-dimensional (2D) and 3D simulations.

  5. Interplay between collective pinning and artificial defects on domain wall propagation in Co/Pt multilayers

    International Nuclear Information System (INIS)

    Rodriguez-Rodriguez, G; Hierro-Rodriguez, A; Perez-Junquera, A; Montenegro, N; Alameda, J M; Velez, M; Menendez, J L; Ravelosona, D

    2010-01-01

    The interplay between collective pinning on intrinsic structural defects and artificial pinning at a patterned hole is studied in magnetic multilayers with perpendicular anisotropy. The pinning strength of a patterned hole is measured through its efficiency to stop domain wall (DW) propagation into a consecutive unpatterned nanowire section (using antisymmetric magnetoresistance to detect the direction of DW propagation) whereas collective pinning is characterized by the field dependence of DW velocity. Close to room temperature, collective pinning becomes weaker than artificial pinning so that pinning at the hole compensates nucleation-pad geometry, blocking DW propagation across the nanowire.

  6. Tracking random walk of individual domain walls in cylindrical nanomagnets with resistance noise.

    Science.gov (United States)

    Singh, Amrita; Mukhopadhyay, Soumik; Ghosh, Arindam

    2010-08-06

    The stochasticity of domain-wall (DW) motion in magnetic nanowires has been probed by measuring slow fluctuations, or noise, in electrical resistance at small magnetic fields. By controlled injection of DWs into isolated cylindrical nanowires of nickel, we have been able to track the motion of the DWs between the electrical leads by discrete steps in the resistance. Closer inspection of the time dependence of noise reveals a diffusive random walk of the DWs with a universal kinetic exponent. Our experiments outline a method with which electrical resistance is able to detect the kinetic state of the DWs inside the nanowires, which can be useful in DW-based memory designs.

  7. Direct Observation of Domain-Wall Surface Tension by Deflating or Inflating a Magnetic Bubble

    Science.gov (United States)

    Zhang, Xueying; Vernier, Nicolas; Zhao, Weisheng; Yu, Haiming; Vila, Laurent; Zhang, Yue; Ravelosona, Dafiné

    2018-02-01

    The surface energy of a magnetic domain wall (DW) strongly affects its static and dynamic behaviors. However, this effect is seldom directly observed, and some of the related phenomena are not well understood. Moreover, a reliable method to quantify the DW surface energy is still absent. Here, we report a series of experiments in which the DW surface energy becomes a dominant parameter. We observe that a semicircular magnetic domain bubble can spontaneously collapse under the Laplace pressure induced by DW surface energy. We further demonstrate that the surface energy can lead to a geometrically induced pinning when the DW propagates in a Hall cross or from a nanowire into a nucleation pad. Based on these observations, we develop two methods to quantify the DW surface energy, which can be very helpful in the estimation of intrinsic parameters such as Dzyaloshinskii-Moriya interactions or exchange stiffness in magnetic ultrathin films.

  8. Nucleation and pinning at 360degree domain walls in SmCo/sub 5/ and related alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gaunt, P.; Mylvaganam, C.K.

    1977-06-01

    It is shown that in a high forward field neighboring 180degree ferromagnetic domain walls come together and either annihilate one another (''unwinding walls'') or combine to form 360degree walls separating domains magnetized in the same direction (''winding walls''). If the 360degree wall encounters:i an inhomogeneity of lower zero-field wall energy (infinityZAK), it may be pinned. A finite reverse field is then required to split the 360degree wall nucleus into two transient 180 degree walls which will reverse the magnetization. The model is developed micromagnetically and applied to the pinning of domain walls at grain boundary inhomogeneities in SmCo/sub 5/ alloys. The nucleation--unpinning coercive field is calculated for inhomogeneities which are assumed to have the magnetic properties of pure cobalt. Inhomogeneity widths from 55.6 to 204 A give coercive forces from zero to 3.8 x 10/sup 4/ Oe..A critical constants chosen, this thickness is 55.6 A It is suggested that one function of liquid-phase sintering may be to increase the inhomogeneity thickness beyond the critical value.

  9. Manipulation of multiple 360o domain wall structures and its current-driven motion in a magnetic nanostripe

    Directory of Open Access Journals (Sweden)

    Wenjun Dong

    2015-11-01

    Full Text Available Dynamics of multiple transverse walls (TWs in a magnetic nanostripe is studied by micromagnetic simulations. It shows that, when TWs are arranged in a stripe with same orientation, they will attract each other and finally annihilate. However, when adjacent TWs are arranged with opposite orientation, a metastable complex wall can be formed, e.g., two TWs lead to 360o wall. For three or more TWs, the formed complex wall includes a number of 360o substructures, which is called multiple 360o structure (M360S here. The M360S itself may be used to store multiple logical data since each 360o substructure can act as logical ”0” or ”1”. On the other hand, the M360S may behave like single TW under an applied current, namely, the M360S can be driven steadily by current like that of single TW. A parity effect of the number of 360o substructures on the critical current for the annihilation is found. Namely, when the number is odd or even, the critical current increase or decrease with the increasing of the number, respectively. The parity effect is relevant to the out-of-plane magnetic moment of the M360S.

  10. Quenched lattice QCD with domain wall fermions and the chiral limit

    International Nuclear Information System (INIS)

    Blum, T.; Wingate, M.; Chen, P.; Christ, N.; Cristian, C.; Fleming, G.; Kaehler, A.; Liao, X.; Liu, G.; Malureanu, C.; Mawhinney, R.; Siegert, G.; Sui, C.; Wu, L.; Zhestkov, Y.; Dawson, C.; Soni, A.; Ohta, S.; Vranas, P.

    2004-01-01

    Quenched QCD simulations on three volumes 8 3 x, 12 3 x and 16 3 x32 and three couplings β=5.7, 5.85 and 6.0 using domain wall fermions provide a consistent picture of quenched QCD. We demonstrate that the small induced effects of chiral symmetry breaking inherent in this formulation can be described by a residual mass (m res ) whose size decreases as the separation between the domain walls (L s ) is increased. However, at stronger couplings much larger values of L s are required to achieve a given physical value of m res . For β=6.0 and L s =16, we find m res /m s =0.033(3), while for β=5.7, and L s =48, m res /m s =0.074(5), where m s is the strange quark mass. These values are significantly smaller than those obtained from a more naive determination in our earlier studies. Important effects of topological near zero modes which should afflict an accurate quenched calculation are easily visible in both the chiral condensate and the pion propagator. These effects can be controlled by working at an appropriately large volume. A non-linear behavior of m π 2 in the limit of small quark mass suggests the presence of additional infrared subtlety in the quenched approximation. Good scaling is seen both in masses and in f π over our entire range, with inverse lattice spacing varying between 1 and 2 GeV

  11. Steady motion of skyrmions and domains walls under diffusive spin torques

    KAUST Repository

    Elías, Ricardo Gabriel

    2017-03-09

    We explore the role of the spin diffusion of conducting electrons in two-dimensional magnetic textures (domain walls and skyrmions) with spatial variation of the order of the spin precession length λex. The effect of diffusion reflects in four additional torques that are third order in spatial derivatives of magnetization and bilinear in λex and in the nonadiabatic parameter β′. In order to study the dynamics of the solitons when these diffusive torques are present, we derive the Thiele equation in the limit of steady motion and we compare the results with the nondiffusive limit. When considering a homogenous current these torques increase the longitudinal velocity of transverse domain walls of width Δ by a factor (λex/Δ)2(α/3), α being the magnetic damping constant. In the case of single skyrmions with core radius r0 these new contributions tend to increase the Magnus effect in an amount proportional to (λex/r0)2(1+2αβ′).

  12. Domain walls of gauged supergravity, M-branes and algebraic curves

    CERN Document Server

    Bakas, I.; Sfetsos, K.

    1999-01-01

    We provide an algebraic classification of all supersymmetric domain wall solutions of maximal gauged supergravity in four and seven dimensions, in the presence of non-trivial scalar fields in the coset SL(8,R)/SO(8) and SL(5,R)/SO(5) respectively. These solutions satisfy first-order equations, which can be obtained using the method of Bogomol'nyi. From an eleven-dimensional point of view they correspond to various continuous distributions of M2- and M5-branes. The Christoffel-Schwarz transformation and the uniformization of the associated algebraic curves are used in order to determine the Schrodinger potential for the scalar and graviton fluctuations on the corresponding backgrounds. In many cases we explicitly solve the Schrodinger problem by employing techniques of supersymmetric quantum mechanics. The analysis is parallel to the construction of domain walls of five-dimensional gauged supergravity, with scalar fields in the coset SL(6,R)/SO(6), using algebraic curves or continuous distributions of D3-brane...

  13. Current-driven domain wall motion based memory devices: Application to a ratchet ferromagnetic strip

    Science.gov (United States)

    Sánchez-Tejerina, Luis; Martínez, Eduardo; Raposo, Víctor; Alejos, Óscar

    2018-04-01

    Ratchet memories, where perpendicular magnetocristalline anisotropy is tailored so as to precisely control the magnetic transitions, has been recently proven to be a feasible device to store and manipulate data bits. For such devices, it has been shown that the current-driven regime of domain walls can improve their performances with respect to the field-driven one. However, the relaxing time required by the traveling domain walls constitutes a certain drawback if the former regime is considered, since it results in longer device latencies. In order to speed up the bit shifting procedure, it is demonstrated here that the application of a current of inverse polarity during the DW relaxing time may reduce such latencies. The reverse current must be sufficiently high as to drive the DW to the equilibrium position faster than the anisotropy slope itself, but with an amplitude sufficiently low as to avoid DW backward shifting. Alternatively, it is possible to use such a reverse current to increase the proper range of operation for a given relaxing time, i.e., the pair of values of the current amplitude and pulse time that ensures single DW jumps for a certain latency time.

  14. Magnetic fingerprint of interfacial coupling between CoFe and nanoscale ferroelectric domain walls

    Science.gov (United States)

    Zhang, Qintong; Murray, Peyton; You, Lu; Wan, Caihua; Zhang, Xuan; Li, Wenjing; Khan, Usman; Wang, Junling; Liu, Kai; Han, Xiufeng

    2016-08-01

    Magnetoelectric coupling in ferromagnetic/multiferroic systems is often manifested in the exchange bias effect, which may have combined contributions from multiple sources, such as domain walls, chemical defects, or strain. In this study we magnetically "fingerprint" the coupling behavior of CoFe grown on epitaxial BiFeO3 (BFO) thin films by magnetometry and the first-order-reversal-curves (FORC). The contribution to exchange bias from 71°, 109° and charged ferroelectric domain walls (DWs) was elucidated by the FORC distribution. CoFe samples grown on BFO with 71° DWs only exhibit an enhancement of the coercivity, but little exchange bias. Samples grown on BFO with 109° DWs and mosaic DWs exhibit a much larger exchange bias, with the main enhancement attributed to 109° and charged DWs. Based on the Malozemoff random field model, a varying-anisotropy model is proposed to account for the exchange bias enhancement. This work sheds light on the relationship between the exchange bias effect of the CoFe/BFO heterointerface and the ferroelectric DWs, and provides a path for multiferroic device analysis and design.

  15. Monte Carlo calculations on the magnetization profile and domain wall structure in bulk systems and nanoconstricitons

    Energy Technology Data Exchange (ETDEWEB)

    Serena, P. A. [Instituto de Ciencias de Materiales de Madrid, Madrid (Spain); Costa-Kraemer, J. L. [Instituto de Microelectronica de Madrid, Madrid (Spain)

    2001-03-01

    A Monte Carlo algorithm suitable to study systems described by an anisotropic Heisenberg Hamiltonian is presented. This technique has been tested successfully with 3D and 2D systems, illustrating how magnetic properties depend on the dimensionality and the coordination number. We have found that magnetic properties of constrictions differ from those appearing in bulk. In particular, spin fluctuations are considerable larger than those calculated for bulk materials. In addition, domain walls are strongly modified when a constriction is present, with a decrease of the domain-wall width. This decrease is explained in terms of previous theoretical works. [Spanish] Se presenta un algoritmo de Monte Carlo para estudiar sistemas discritos por un hamiltoniano anisotropico de Heisenburg. Esta tecnica ha sido probada exitosamente con sistemas de dos y tres dimensiones, ilustrado con las propiedades magneticas dependen de la dimensionalidad y el numero de coordinacion. Hemos encontrado que las propiedades magneticas de constricciones difieren de aquellas del bulto. En particular, las fluctuaciones de espin son considerablemente mayores. Ademas, las paredes de dominio son fuertemente modificadas cuando una construccion esta presente, originando un decrecimiento del ancho de la pared de dominio. Damos cuenta de este decrecimiento en terminos de un trabajo teorico previo.

  16. Enhancement of spin Hall effect induced torques for current-driven magnetic domain wall motion: Inner interface effect

    KAUST Repository

    Bang, Do

    2016-05-23

    We investigate the current-induced domain wall motion in perpendicular magnetized Tb/Co wires with structure inversion asymmetry and different layered structures. We find that the critical current density to drive domain wall motion strongly depends on the layered structure. The lowest critical current density ∼15MA/cm2 and the highest slope of domain wall velocity curve are obtained for the wire having thin Co sublayers and more inner Tb/Co interfaces, while the largest critical current density ∼26MA/cm2 required to drive domain walls is observed in the Tb-Co alloy magnetic wire. It is found that the Co/Tb interface contributes negligibly to Dzyaloshinskii-Moriya interaction, while the effective spin-orbit torque strongly depends on the number of Tb/Co inner interfaces (n). An enhancement of the antidamping torques by extrinsic spin Hall effect due to Tb rare-earth impurity-induced skew scattering is suggested to explain the high efficiency of current-induced domain wall motion.

  17. Pseudoscalar meson in two flavors QCD with the optimal domain-wall fermion

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Ting-Wai [Physics Department, National Taiwan University, Taipei 10617, Taiwan (China); Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Hsieh, Tung-Han, E-mail: thhsieh@gate.sinica.edu.tw [Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan (China); Mao, Yao-Yuan [Physics Department, National Taiwan University, Taipei 10617, Taiwan (China)

    2012-10-31

    We perform hybrid Monte Carlo (HMC) simulations of two flavors QCD with the optimal domain-wall fermion (ODWF), on the 16{sup 3} Multiplication-Sign 32 lattice (with lattice spacing a{approx}0.1 fm), for eight sea-quark masses corresponding to pion masses in the range 228-565 MeV. We calculate the mass and the decay constant of the pseudoscalar meson, and compare our data with the chiral perturbation theory (ChPT). We find that our data is in good agreement with the sea-quark mass dependence predicted by the next-to-leading order (NLO) ChPT, and provides a determination of the low-energy constants l{sup Macron }{sub 3} and l{sup Macron }{sub 4}, the pion decay constant, the chiral condensate, and the average up and down quark mass.

  18. Current-driven domain wall motion enhanced by the microwave field

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xi-guang; Guo, Guang-hua, E-mail: guogh@mail.csu.edu.cn; Nie, Yao-zhuang; Wang, Dao-wei; Li, Zhi-xiong; Tang, Wei [School of Physics and Electronics, Central South University, Changsha 410083 (China); Zeng, Zhong-ming [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China)

    2014-07-14

    The magnetic domain wall (DW) motion driven by a spin-polarized current opens a new concept for memory and logic devices. However, the critical current density required to overcome the intrinsic and/or extrinsic pinning of DW remains too large for practical applications. Here, we show, by using micromagnetic simulations and analytical approaches, that the application of a microwave field offers an effective solution to this problem. When a transverse microwave field is applied, the adiabatic spin-transfer torque (STT) alone can sustain a steady-state DW motion without the sign of Walker breakdown, meaning that the intrinsic pinning disappears. The extrinsic pinning can also be effectively reduced. Moreover, the DW velocity is increased greatly for the microwave-assisted DW motion. This provides a new way to manipulate the DW motion at low current densities.

  19. Possible method to observe the breathing mode of a magnetic domain wall in the Josephson junction

    International Nuclear Information System (INIS)

    Mori, Michiyasu; Maekawa, Sadamichi; Koshibae, Wataru; Hikino, Shin-ichi

    2014-01-01

    A magnetic domain wall (DW) behaves as a massive particle with elasticity. Sliding and oscillation of the DW have been observed experimentally, whereas vibration of a width in the DW, ‘breathing mode’, has not been measured so far. We theoretically propose how to observe the breathing mode by the Josephson junction having a ferromagnetic layer between superconducting electrodes. The current-voltage (I-V) curve is calculated by an equivalent circuit of the resistively shunted junction model. The breathing mode is identified by stepwise structures in the I-V curve, which appear at the voltages V = n (ℏ/2e)ω with the fundamental constant ℏ/e, integer number n and the frequency of the breathing mode ω. (paper)

  20. An Analytical Time Domain Solution for the Forced Vibration Analysis of Thick-Walled Cylinders

    Directory of Open Access Journals (Sweden)

    Bashir Movahedian

    Full Text Available Abstract In this paper, we propose a time domain analytical solution for the forced vibration analysis of thick-walled hollow cylinders in presence of polar orthotropy. In this regard, solution of the governing equation is decomposed into two parts. The role of the first one is to satisfy boundary conditions utilizing the method of separation of variables besides of Fourier series expansion of the non-homogenous boundary conditions. The second part has been also expressed as the series of orthogonal characteristic functions with the aim of satisfaction of initial conditions. The proposed analytical solution has been implemented to evaluate the dynamic response of the cylinder in solution of some sample problems which are chosen from previous studies.

  1. Vortices and domain walls: 'Wormholes' in unconventional superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bessarab, P F [St. Petersburg State University, Universitetskaya nab. 7/9, 199164 St. Petersburg (Russian Federation); Radievsky, A V, E-mail: van_der_paul@yahoo.co.u [Immanuel Kant State University of Russia, Nevskogo str. 14, 236016 Kaliningrad (Russian Federation)

    2010-01-15

    In the framework of the 2D and 3D time-dependent Ginzburg-Landau model we study superconductors with multicomponent order parameter (d-pairing). We argue that topological defects inside the sample do affect its thermodynamic properties such as hysteresis loop, susceptibility, etc. Along with earlier known topological defects such as Abrikosov vortices, domain walls (DWs) which separate different magnetic phases and even vortices inside the DW, we found an interesting combination of DWs and vortices. Namely we show that equivalent magnetic phases may be linked together with a vortex going through the other magnetic phase. This configuration may correspond to a stable state even in a zero external magnetic field. We also mention that this configuration is topologically similar to the 'wormholes' in the quantum gravity.

  2. Easy moment direction and antiferromagnetic domain wall motion in Mn{sub 2}Au

    Energy Technology Data Exchange (ETDEWEB)

    Barthem, Vitoria M.T.S. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Ilha do Fundao, 21941-972 Rio de Janeiro (Brazil); Colin, Claire V.; Haettel, Richard; Dufeu, Didier [Université Grenoble Alpes, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France); CNRS, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France); Givord, Dominique, E-mail: dominique.givord@neel.cnrs.fr [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Ilha do Fundao, 21941-972 Rio de Janeiro (Brazil); Université Grenoble Alpes, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France); CNRS, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France)

    2016-05-15

    The interest of giving active functions to antiferromagnetic (AFM) materials in spintronics devices has been realized recently. Mn{sub 2}Au is a high-Néel temperature antiferromagnet with large Mn moment, lying in plane of the tetragonal structure. To determine the direction of the moments in Mn{sub 2}Au, an original approach is demonstrated, which should be generic to planar AFM materials. It involves the rotation of the granular sample around an axis perpendicular to the applied magnetic field. The family of easy moment directions is 〈110〉. For grains prevented from rotating, the dominant magnetization process is AFM domain wall motion. Textured Mn{sub 2}Au nanoelements could be introduced in spintronics devices, in which the Mn moments would be switched under modest external excitation.

  3. fK /f{pi} in Full QCD with Domain Wall Valence Quarks

    Energy Technology Data Exchange (ETDEWEB)

    Silas Beane; Paulo Bedaque; Konstantinos Orginos; Martin Savage

    2007-05-01

    We compute the ratio of pseudoscalar decay constants f{sub K}/f{sub {pi}} using domain-wall valence quarks and rooted improved Kogut-Susskind sea quarks. By employing continuum chiral perturbation theory, we extract the Gasser-Leutwyler low-energy constant L{sub 5}, and extrapolate f{sub K}/f{sub {pi}} to the physical point. We find: f{sub K}/f{sub {pi}} = 1.218 {+-} 0.002{sub -0.024}{sup +0.011} where the first error is statistical and the second error is an estimate of the systematic due to chiral extrapolation and fitting procedures. This value agrees within the uncertainties with the determination by the MILC collaboration, calculated using Kogut-Susskind valence quarks, indicating that systematic errors arising from the choice of lattice valence quark are small.

  4. Exact pseudofermion action for Monte Carlo simulation of domain-wall fermion

    Directory of Open Access Journals (Sweden)

    Yu-Chih Chen

    2014-11-01

    Full Text Available We present an exact pseudofermion action for hybrid Monte Carlo simulation (HMC of one-flavor domain-wall fermion (DWF, with the effective 4-dimensional Dirac operator equal to the optimal rational approximation of the overlap-Dirac operator with kernel H=cHw(1+dγ5Hw−1, where c and d are constants. Using this exact pseudofermion action, we perform HMC of one-flavor QCD, and compare its characteristics with the widely used rational hybrid Monte Carlo algorithm (RHMC. Moreover, to demonstrate the practicality of the exact one-flavor algorithm (EOFA, we perform the first dynamical simulation of the (1+1-flavors QCD with DWF.

  5. Selective Killing of Pathogenic Bacteria by Antimicrobial Silver Nanoparticle - Cell Wall Binding Domain (CBD) Conjugates.

    Science.gov (United States)

    Kim, Domyoung; Kwon, Seok Joon; Wu, Xia; Sauve, Jessica; Lee, Inseon; Nam, Jahyun; Kim, Jungbae; Dordick, Jonathan S

    2018-04-05

    Broad-spectrum antibiotics indiscriminately kill bacteria, removing non-pathogenic microorganisms and leading to evolution of antibiotic resistant strains. Specific antimicrobials that could selectively kill pathogenic bacteria without targeting other bacteria in the natural microbial community or microbiome may be able to address this concern. In this work, we demonstrate that silver nanoparticles, suitably conjugated to a selective cell wall binding domain (CBD), can efficiently target and selectively kill bacteria. As a relevant example, CBDBA from Bacillus anthracis selectively bound to B. anthracis in a mixture with B. subtilis, as well in a mixture with Staphylococcus aureus. This new biologically-assisted hybrid strategy, therefore, has the potential to provide selective decontamination of pathogenic bacteria with minimal impact on normal microflora.

  6. Adsorbate induced domain-wall ordering on silicon(111); Adsorbatinduzierte Domaenenwandordnung auf Silizium(111)

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, C.

    2006-09-14

    The gold-induced (5 x 2)-reconstruction on the Si(111) surface has been investigated in detail. Investigations with scanning tunneling microscopy, electron diffraction and simple electron diffraction simulation as combining element are presented. The defect density in the (5 x 2)-reconstructed areas has been analysed in dependency on temperature and gold density on the surface. One important result is the categorization of this reconstruction as domain-wall reconstruction like the other gold induced reconstructions on this surface in the submonolayer-coverage regime. The correlation of the adatoms on the (5 x 2)-reconstructed areas is analysed and the silicon coverage in the areas is determined from the growth dynamics of the reconstruction. Based on this, a new model, which has been developed in cooperation with Steve Erwin from the Naval Research Center, Washington, is presented. (orig.)

  7. Condition of the ratchet effect of a magnetic domain wall motion under an asymmetric potential energy

    Science.gov (United States)

    Piao, Hong-Guang; Zhang, Xiaozhong; Choi, Hyeok-Cheol; Kim, Dong-Hyun; You, Chun-Yeol

    2012-04-01

    We have investigated the ratchet effect of magnetic domain wall (DW) motion in a straight ferromagnetic nanowire under ac magnetic field by means of micromagnetic simulation. A structure-stable DW ratchet effect along the ferromagnetic nanowire is observed utilizing an asymmetric potential produced by a nonuniform magnetostatic stray field from an array of a periodic non-contact trapezoidal stubs. A diode-like consecutive operation process for a transverse DW motion is examined with variation of the ac field frequency and amplitude, where the necessary conditions for the DW ratchet effect are systematically examined. We have also obtained the empirical relation between a DW velocity of the ratchet effect and the ac field frequency and amplitude.

  8. Coercivity of domain wall motion in thin films of amorphous rare earth-transition metal alloys

    Science.gov (United States)

    Mansuripur, M.; Giles, R. C.; Patterson, G.

    1991-01-01

    Computer simulations of a two dimensional lattice of magnetic dipoles are performed on the Connection Machine. The lattice is a discrete model for thin films of amorphous rare-earth transition metal alloys, which have application as the storage media in erasable optical data storage systems. In these simulations, the dipoles follow the dynamic Landau-Lifshitz-Gilbert equation under the influence of an effective field arising from local anisotropy, near-neighbor exchange, classical dipole-dipole interactions, and an externally applied field. Various sources of coercivity, such as defects and/or inhomogeneities in the lattice, are introduced and the subsequent motion of domain walls in response to external fields is investigated.

  9. Mesoscopic Metal-Insulator Transition at Ferroelastic Domain Walls in VO2

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Keith M [ORNL; Kalinin, Sergei V [ORNL; Kolmakov, Andrei [ORNL; Luk' yanchuk, Prof. Igor A. [University of Picardie Jules Verne, Amiens, France; Meunier, Vincent [ORNL; Proksch, Roger [Asylum Research, Santa Barbara, CA; Shelton Jr, William Allison [ORNL; Strelcov, Evgheni [Southern Illinois University; Tselev, Alexander [ORNL

    2010-01-01

    The novel phenomena induced by symmetry breaking at homointerfaces between ferroic variants in ferroelectric and ferroelastic materials have attracted recently much attention. Using variable temperature scanning microwave microscopy, we demonstrate the mesoscopic strain-induced metal-insulator phase transitions in the vicinity of ferroelastic domain walls in the semiconductive VO2 that nucleated at temperatures as much as 10-12 C below bulk transition, resulting in the formation of conductive channels in the material. Density functional theory is used to rationalize the process low activation energy. This behavior, linked to the strain inhomogeneity inherent in ferroelastic materials, can strongly affect interpretation of phase-transition studies in VO2 and similar materials with symmetry-lowering transitions, and can also be used to enable new generations of electronic devices though strain engineering of conductive and semiconductive regions.

  10. Atiyah-Patodi-Singer index from the domain-wall fermion Dirac operator

    Science.gov (United States)

    Fukaya, Hidenori; Onogi, Tetsuya; Yamaguchi, Satoshi

    2017-12-01

    The Atiyah-Patodi-Singer (APS) index theorem attracts attention for understanding physics on the surface of materials in topological phases. The mathematical setup for this theorem is, however, not directly related to the physical fermion system, as it imposes on the fermion fields a nonlocal boundary condition known as the "APS boundary condition" by hand, which is unlikely to be realized in the materials. In this work, we attempt to reformulate the APS index in a "physicist-friendly" way for a simple setup with U (1 ) or S U (N ) gauge group on a flat four-dimensional Euclidean space. We find that the same index as APS is obtained from the domain-wall fermion Dirac operator with a local boundary condition, which is naturally given by the kink structure in the mass term. As the boundary condition does not depend on the gauge fields, our new definition of the index is easy to compute with the standard Fujikawa method.

  11. Soliton-like magnetic domain wall motion induced by the interfacial Dzyaloshinskii-Moriya interaction

    Science.gov (United States)

    Ono, Teruo

    Topological defects such as magnetic solitons, vortices, Bloch lines, and skyrmions start to play an important role in modern magnetism due to their extraordinary stability which can be hailed as future memory devices. Recently, novel type of antisymmetric exchange interaction, namely the Dzyaloshinskii-Moriya interaction (DMI), has been uncovered and found to influence on the formation of topological defects. Exploring how the DMI affects the dynamics of topological defects is therefore an important task. Here we investigate the dynamics of the magnetic domain wall (DW) under a DMI by developing a time-of-flight measurement scheme which allows us to measure the DW velocity for magnetic fields up to 0.3T. For a weak DMI, the trend of DW velocity follows the Walker's model which predicts that the velocity of DW increases with field up to a threshold (Walker field) and decreases abruptly. On the other hand, for a strong DMI, velocity breakdown is completely suppressed and the DW keeps its maximum velocity even far above the Walker field. Such a distinct trend of the DW velocity, which has never been predicted, can be explained in terms of magnetic soliton, of which topology can be protected by the DMI. Importantly, such a soliton-like DW motion is only observed in two dimensional systems, implying that the vertical Bloch lines (VBLs) creating inside of the magnetic domain-wall play a crucial role. This work was partly supported by JSPS KAKENHI Grant Numbers 15H05702, 26870300, 26870304, 26103002, 25.4251, Collaborative Research Program of the Institute for Chemical Research, Kyoto University, and R & D Project for ICT Key Technology of MEXT from the Japan Society for the Promotion of Science (JSPS).

  12. Substructure hybrid testing of reinforced concrete shear wall structure using a domain overlapping technique

    Science.gov (United States)

    Zhang, Yu; Pan, Peng; Gong, Runhua; Wang, Tao; Xue, Weichen

    2017-10-01

    An online hybrid test was carried out on a 40-story 120-m high concrete shear wall structure. The structure was divided into two substructures whereby a physical model of the bottom three stories was tested in the laboratory and the upper 37 stories were simulated numerically using ABAQUS. An overlapping domain method was employed for the bottom three stories to ensure the validity of the boundary conditions of the superstructure. Mixed control was adopted in the test. Displacement control was used to apply the horizontal displacement, while two controlled force actuators were applied to simulate the overturning moment, which is very large and cannot be ignored in the substructure hybrid test of high-rise buildings. A series of tests with earthquake sources of sequentially increasing intensities were carried out. The test results indicate that the proposed hybrid test method is a solution to reproduce the seismic response of high-rise concrete shear wall buildings. The seismic performance of the tested precast high-rise building satisfies the requirements of the Chinese seismic design code.

  13. Insights into Substrate Specificity of NlpC/P60 Cell Wall Hydrolases Containing Bacterial SH3 Domains

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qingping; Mengin-Lecreulx, Dominique; Liu, Xueqian W.; Patin, Delphine; Farr, Carol L.; Grant, Joanna C.; Chiu, Hsiu-Ju; Jaroszewski, Lukasz; Knuth, Mark W.; Godzik, Adam; Lesley, Scott A.; Elsliger, Marc-André; Deacon, Ashley M.; Wilson, Ian A.

    2015-09-15

    ABSTRACT

    Bacterial SH3 (SH3b) domains are commonly fused with papain-like Nlp/P60 cell wall hydrolase domains. To understand how the modular architecture of SH3b and NlpC/P60 affects the activity of the catalytic domain, three putative NlpC/P60 cell wall hydrolases were biochemically and structurally characterized. These enzymes all have γ-d-Glu-A2pm (A2pm is diaminopimelic acid) cysteine amidase (ordl-endopeptidase) activities but with different substrate specificities. One enzyme is a cell wall lysin that cleaves peptidoglycan (PG), while the other two are cell wall recycling enzymes that only cleave stem peptides with an N-terminall-Ala. Their crystal structures revealed a highly conserved structure consisting of two SH3b domains and a C-terminal NlpC/P60 catalytic domain, despite very low sequence identity. Interestingly, loops from the first SH3b domain dock into the ends of the active site groove of the catalytic domain, remodel the substrate binding site, and modulate substrate specificity. Two amino acid differences at the domain interface alter the substrate binding specificity in favor of stem peptides in recycling enzymes, whereas the SH3b domain may extend the peptidoglycan binding surface in the cell wall lysins. Remarkably, the cell wall lysin can be converted into a recycling enzyme with a single mutation.

    IMPORTANCEPeptidoglycan is a meshlike polymer that envelops the bacterial plasma membrane and bestows structural integrity. Cell wall lysins and recycling enzymes are part of a set of lytic enzymes that target covalent bonds connecting the amino acid and amino sugar building blocks of the PG network. These hydrolases are involved in processes such as cell growth and division, autolysis, invasion, and PG turnover and recycling. To avoid cleavage of unintended substrates, these enzymes have very selective substrate specificities. Our biochemical and structural

  14. Magnetic domain-wall motion study under an electric field in a Finemet{sup ®} thin film on flexible substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Ngo Thi [Laboratoire des Sciences des Procédés et des Matériaux, CNRS-Université Paris XIII, 93430 Villetaneuse (France); Mercone, Silvana, E-mail: silvana.mercone@univ-paris13.fr [Laboratoire des Sciences des Procédés et des Matériaux, CNRS-Université Paris XIII, 93430 Villetaneuse (France); Moulin, Johan [Institut d' Electronique Fondamentale, UMR 8622 Université Paris Sud/CNRS, Orsay (France); Bahoui, Anouar El; Faurie, Damien; Zighem, Fatih; Belmeguenai, Mohamed; Haddadi, Halim [Laboratoire des Sciences des Procédés et des Matériaux, CNRS-Université Paris XIII, 93430 Villetaneuse (France)

    2015-01-01

    We study the influence of applied in-plane elastic strains on the static magnetic configuration of a 530 nm magnetostrictive FeCuNbSiB (Finemet{sup ®}) thin film. The in-plane strains are induced via the application of a voltage to a piezoelectric actuator on which the film/substrate system was glued. A quantitative characterization of the voltage dependence of the induced-strain at the surface of the film was performed using a digital image correlation technique. Magnetic Force Microscopy (MFM) images at remanence (H=0 Oe and U=0 V) clearly reveal the presence of weak stripe domains. The effect of the voltage-induced strain shows the existence of a voltage threshold value for the strike configuration break. For a maximum strain of ε{sub XX}∼0.5×10{sup −3} we succeed in destabilizing the stripes configuration helping the setting up of a complete homogeneous magnetic pattern. - Highlights: • Elastic strain effect on the magnetic domain structure of a Finemet/Kapton is investigated. • External loading is applied thanks to a piezo-actuator on which the sample is glued. • The amount of strains was measured by the Digital Image Correlation technique. • Magnetic Force Microscopy showed high mobility of magnetic stripes domains. • Bending, curving and branching of domains go into maze-like pattern.

  15. Steady-state domain wall motion driven by adiabatic spin-transfer torque with assistance of microwave field

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xi-guang; Guo, Guang-hua, E-mail: guogh@mail.csu.edu.cn; Nie, Yao-zhuang; Xia, Qing-lin; Tang, Wei [School of Physics and Electronics, Central South University, Changsha 410083 (China); Wang, D. [Department of Physics, National University of Defense Technology, Changsha 410073 (China); Zeng, Zhong-ming [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China)

    2013-12-23

    We have studied the current-induced displacement of a 180° Bloch wall by means of micromagnetic simulation and analytical approach. It is found that the adiabatic spin-transfer torque can sustain a steady-state domain wall (DW) motion in the direction opposite to that of the electron flow without Walker Breakdown when a transverse microwave field is applied. This kind of motion is very sensitive to the microwave frequency and can be resonantly enhanced by exciting the domain wall thickness oscillation mode. A one-dimensional analytical model was established to account for the microwave-assisted wall motion. These findings may be helpful for reducing the critical spin-polarized current density and designing DW-based spintronic devices.

  16. Characterization of applied tensile stress using domain wall dynamic behavior of grain-oriented electrical steel

    Science.gov (United States)

    Qiu, Fasheng; Ren, Wenwei; Tian, Gui Yun; Gao, Bin

    2017-06-01

    Stress measurement that provides early indication of stress status has become increasingly demanding in the field of Non-destructive testing and evaluation (NDT&E). Bridging the correlation between micro magnetic properties and the applied tensile stress is the first conceptual step to come up with a new method of non-destructive testing. This study investigates the characterization of applied tensile stress with in-situ magnetic domain imaging and their dynamic behaviors by using magneto-optical Kerr effect (MOKE) microscopy assisted with magneto-optical indicator film (MOIF). Threshold magnetic field (TMF) feature to reflect 180 ° domain wall (DW) characteristics behaviors in different grains is proposed for stress detection. It is verified that TMF is a threshold feature with better sensitivity and brings linear correlation for stress characterization in comparison to classical coercive field, remanent magnetization, hysteresis loss and permeability parameters. The results indicate that 180 ° DWs dynamic in the inner grain is highly correlated with stress. The DW dynamics of turn over (TO) tests for different grains is studied to illustrate the repeatability of TMF. Experimental tests of high permeability grain oriented (HGO) electrical steels under stress loading have been conducted to verify this study.

  17. Imaging and tuning polarity at SrTiO3 domain walls

    Science.gov (United States)

    Frenkel, Yiftach; Haham, Noam; Shperber, Yishai; Bell, Christopher; Xie, Yanwu; Chen, Zhuoyu; Hikita, Yasuyuki; Hwang, Harold Y.; Salje, Ekhard K. H.; Kalisky, Beena

    2017-12-01

    Electrostatic fields tune the ground state of interfaces between complex oxide materials. Electronic properties, such as conductivity and superconductivity, can be tuned and then used to create and control circuit elements and gate-defined devices. Here we show that naturally occurring twin boundaries, with properties that are different from their surrounding bulk, can tune the LaAlO3/SrTiO3 interface 2DEG at the nanoscale. In particular, SrTiO3 domain boundaries have the unusual distinction of remaining highly mobile down to low temperatures, and were recently suggested to be polar. Here we apply localized pressure to an individual SrTiO3 twin boundary and detect a change in LaAlO3/SrTiO3 interface current distribution. Our data directly confirm the existence of polarity at the twin boundaries, and demonstrate that they can serve as effective tunable gates. As the location of SrTiO3 domain walls can be controlled using external field stimuli, our findings suggest a novel approach to manipulate SrTiO3-based devices on the nanoscale.

  18. Hysteresis loop design by geometry of garnet film element with single domain wall

    International Nuclear Information System (INIS)

    Skidanov, V A; Vetoshko, P M; Stempkovskiy, A L

    2011-01-01

    Numerical modeling and experimental investigation of magnetostatic stable states of two-domain structure in Bi-substituted uniaxial garnet film elements was made. Single domain walls (DW) between two opposite normally magnetized parts in isolated rectangular strip and strip-like bridge are found to exhibit different behavior. DW inside strip (bridge) suffers increasing repulsion (attraction) from nearest edge when shifted from element center. DW position center position is stable in isolated strip but bridge is magnetized spontaneously to one of two saturated states in zero external field. Isolated strip magnetization process occurs reversibly while bridge magnetization reversal occurs by coercive manner. Strip susceptibility and bridge coercive field are entirely defined by magnetostatic barrier created by element boundary stray field in case of constant DW length during magnetization reversal. Variation of strip and bridge boundary shape along DW trajectory gives the opportunity to create additional controllable potential profile due to DW surface energy modulation by DW length. Garnet elements with high Faraday rotation and low light switching field were developed for fine magnetic sensing and optical data processing applications.

  19. Dispersion relation and unphysical poles of Möbius domain-wall fermions in free field theory at finite Ls

    Science.gov (United States)

    Tomii, Masaaki

    2018-03-01

    We investigate the dispersion relation of Möbius domain-wall fermions in free field theory at finite Ls. We find that there are Ls - 1 extra poles of Möbius domain-wall fermions in addition to the pole which realizes the physical mode in the continuum limit. The unphysical contribution of these extra poles could be significant when we introduce heavy quarks. We show in this report the fundamental properties of these unphysical poles and discuss the optimal choice of Möbius parameters to minimize their contribution to four-dimensional physics.

  20. Lytic activity of the staphylolytic Twort phage endolysin CHAP domain is enhanced by the SH3b cell wall binding domain.

    Science.gov (United States)

    Becker, Stephen C; Swift, Steven; Korobova, Olga; Schischkova, Nina; Kopylov, Pavel; Donovan, David M; Abaev, Igor

    2015-01-01

    Increases in the prevalence of antibiotic-resistant strains of Staphylococcus aureus have elicited efforts to develop novel antimicrobials to treat these drug-resistant pathogens. One potential treatment repurposes the lytic enzymes produced by bacteriophages as antimicrobials. The phage Twort endolysin (PlyTW) harbors three domains, a cysteine, histidine-dependent amidohydrolases/peptidase domain (CHAP), an amidase-2 domain and a SH3b-5 cell wall binding domain (CBD). Our results indicate that the CHAP domain alone is necessary and sufficient for lysis of live S. aureus, while the amidase-2 domain is insufficient for cell lysis when provided alone. Loss of the CBD results in ∼10X reduction of enzymatic activity in both turbidity reduction and plate lysis assays compared to the full length protein. Deletion of the amidase-2 domain resulted in a protein (PlyTW Δ172-373) with lytic activity that exceeded the activity of the full length construct in both the turbidity reduction and plate lysis assays. Addition of Ca(2+) enhanced the turbidity reduction activity of both the full length protein and truncation constructs harboring the CHAP domain. Chelation by addition of EDTA or the addition of zinc inhibited the activity of all PlyTW constructs. Published by Oxford University Press on behalf of FEMS 2014. This work is written by US Government employees and is in the public domain in the US.

  1. Piezoelectric properties of twinned ferroelectric perovskites with head-to-head and tail-to-tail domain walls

    Czech Academy of Sciences Publication Activity Database

    Ondrejkovič, Petr; Márton, Pavel; Guennou, Mael; Setter, N.; Hlinka, Jiří

    2013-01-01

    Roč. 88, č. 2 (2013), "024114-1"-"024114-9" ISSN 1098-0121 Grant - others:7th Framework Programme(XE) 268058 Institutional support: RVO:68378271 Keywords : piezoelectric properties * charged domain walls * domain structure * twinned ferroelectric Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.664, year: 2013 http://link. aps .org/doi/10.1103/PhysRevB.88.024114

  2. Role of net charge on catalytic domain and influence of cell wall binding domain on bactericidal activity, specificity, and host range of phage lysins.

    Science.gov (United States)

    Low, Lieh Yoon; Yang, Chen; Perego, Marta; Osterman, Andrei; Liddington, Robert

    2011-09-30

    The recombinant lysins of lytic phages, when applied externally to Gram-positive bacteria, can be efficient bactericidal agents, typically retaining high specificity. Their development as novel antibacterial agents offers many potential advantages over conventional antibiotics. Protein engineering could exploit this potential further by generating novel lysins fit for distinct target populations and environments. However, access to the peptidoglycan layer is controlled by a variety of secondary cell wall polymers, chemical modifications, and (in some cases) S-layers and capsules. Classical lysins require a cell wall-binding domain (CBD) that targets the catalytic domain to the peptidoglycan layer via binding to a secondary cell wall polymer component. The cell walls of Gram-positive bacteria generally have a negative charge, and we noticed a correlation between (positive) charge on the catalytic domain and bacteriolytic activity in the absence of the CBD (nonclassical behavior). We investigated a physical basis for this correlation by comparing the structures and activities of pairs of lysins where the lytic activity of one of each pair was CBD-independent. We found that by engineering a reversal of sign of the net charge of the catalytic domain, we could either eliminate or create CBD dependence. We also provide evidence that the S-layer of Bacillus anthracis acts as a molecular sieve that is chiefly size-dependent, favoring catalytic domains over full-length lysins. Our work suggests a number of facile approaches for fine-tuning lysin activity, either to enhance or reduce specificity/host range and/or bactericidal potential, as required.

  3. Interplay of domain walls and magnetization rotation on dynamic magnetization process in iron/polymer–matrix soft magnetic composites

    Energy Technology Data Exchange (ETDEWEB)

    Dobák, Samuel, E-mail: samuel.dobak@student.upjs.sk [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik University, Park Angelinum 9, 041 54 Košice (Slovakia); Füzer, Ján; Kollár, Peter [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik University, Park Angelinum 9, 041 54 Košice (Slovakia); Fáberová, Mária; Bureš, Radovan [Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 043 53 Košice (Slovakia)

    2017-03-15

    This study sheds light on the dynamic magnetization process in iron/resin soft magnetic composites from the viewpoint of quantitative decomposition of their complex permeability spectra into the viscous domain wall motion and magnetization rotation. We present a comprehensive view on this phenomenon over the broad family of samples with different average particles dimension and dielectric matrix content. The results reveal the pure relaxation nature of magnetization processes without observation of spin resonance. The smaller particles and higher amount of insulating resin result in the prevalence of rotations over domain wall movement. The findings are elucidated in terms of demagnetizing effects rising from the heterogeneity of composite materials. - Highlights: • A first decomposition of complex permeability into domain wall and rotation parts in soft magnetic composites. • A pure relaxation nature of dynamic magnetization processes. • A complete loss separation in soft magnetic composites. • The domain walls activity is considerably suppressed in composites with smaller iron particles and higher matrix content. • The demagnetizing field acts as a significant factor at the dynamic magnetization process.

  4. Higher Dimensional LRS Bianchi Type-I Domain Walls in a Scalar-Tensor Theory of Gravitation

    Science.gov (United States)

    Katore, S. D.; Adhav, K. S.; Shaikh, A. Y.; Sarkate, N. K.

    2010-10-01

    An exact higher dimensional LRS Bianchi type-I cosmological model is obtained in presence of thick domain walls in a scalar tensor theory of gravitation proposed by Saez and Ballester (Phys. Lett. A113:467, 1985). Some physical and kinematical properties of the models are also discussed.

  5. Contribution of the irreversible displacement of domain walls to the piezoelectric effect in barium titanate and lead zirconate titanate ceramics

    CERN Document Server

    Damjanovic, D

    1997-01-01

    The contribution from the irreversible displacement of non-180 deg domain walls to the direct longitudinal piezoelectric d sub 3 sub 3 coefficient of BaTiO sub 3 and Pb(Zr, Ti)O sub 3 ceramics was determined quantitatively by using the Rayleigh law. Effects of the crystal structure and microstructure of the ceramics as well as the external d.c. pressure on the domain wall contribution to d sub 3 sub 3 were examined. In barium titanate, this domain wall contribution is large (up to 35% of the total d sub 3 sub 3 , under the experimental conditions used) and dependent on the external d.c. pressure in coarse grained ceramics, and much smaller and independent of the external d.c. pressure in fine-grained samples. The presence of internal stresses in fine-grained ceramics could account for the observed behaviour. The analysis shows that the domain-wall contribution to the d sub 3 sub 3 in lead zirconate titanate ceramics is large in compositions close to the morphotropic phase boundary that contain a mixture of te...

  6. Domain walls and perturbation theory in high temperature gauge theory SU(2) in 2+1 dimensions

    CERN Document Server

    Korthals-Altes, C P; Stephanov, M A; Teper, M; Altes, C Korthals

    1997-01-01

    We study the detailed properties of Z_2 domain walls in the deconfined high temperature phase of the d=2+1 SU(2) gauge theory. These walls are studied both by computer simulations of the lattice theory and by one-loop perturbative calculations. The latter are carried out both in the continuum and on the lattice. We find that leading order perturbation theory reproduces the detailed properties of these domain walls remarkably accurately even at temperatures where the effective dimensionless expansion parameter, g^2/T, is close to unity. The quantities studied include the surface tension, the action density profiles, roughening and the electric screening mass. It is only for the last quantity that we find an exception to the precocious success of perturbation theory. All this shows that, despite the presence of infrared divergences at higher orders, high-T perturbation theory can be an accurate calculational tool.

  7. Domain walls and perturbation theory in high-temperature gauge theory: SU(2) in 2+1 dimensions

    International Nuclear Information System (INIS)

    Korthals Altes, C.; Michels, A.; Teper, M.; Stephanov, M.

    1997-01-01

    We study the detailed properties of Z 2 domain walls in the deconfined high-temperature phase of the d=2+1 SU(2) gauge theory. These walls are studied both by computer simulations of the lattice theory and by one-loop perturbative calculations. The latter are carried out both in the continuum and on the lattice. We find that leading order perturbation theory reproduces the detailed properties of these domain walls remarkably accurately even at temperatures where the effective dimensionless expansion parameter g 2 /T is close to unity. The quantities studied include the surface tension, the action density profiles, roughening, and the electric screening mass. It is only for the last quantity that we find an exception to the precocious success of perturbation theory. All this shows that, despite the presence of infrared divergences at higher orders, high-T perturbation theory can be an accurate calculational tool. copyright 1997 The American Physical Society

  8. Influence of temperature on the critical in-plane field range for VBLs in the walls of hard domains

    International Nuclear Information System (INIS)

    Nie, X.F.; Guo, G.X.; Xu, J.P.; Liu, S.P.; Wang, L.N.; Huo, S.G.

    2006-01-01

    The influence of temperature on the critical in-plane field range for vertical Bloch lines in the walls of three kinds of hard domains is investigated experimentally. It is found that for each kind of three hard domains, there exists a critical in-plane field range, i. e. [H ip (1) (T),H ip (2) (T)], which depends on temperatures and in which vertical Bloch lines are unstable. Here, H ip (1) (T) is the initial critical in-plane field where VBLs in the walls of three kinds of hard domains are annihilated, and H ip (2) (T) is the lowest in-plane field where VBLs in their corresponding hard domains are annihilated completely. H ip (1) (T), H ip (2) (T) and [H ip (1) (T),H ip (2) (T)], all decrease as the temperature increase. Furthermore, H ip (1) (T) and H ip (2) (T) reach zero at T 0 1 and T 0 , respectively. In addition, there exists a relationship among them, when T is unchanged, H ip (1) (T) of the three kinds of hard domains (ordinary hard bubbles (OHB), first kind of dumbbell domain (ID) and second kind of dumbbell domains (IID)) decrease successively, and theirH ip (2) (T) are the same

  9. Magnetic properties, domain-wall creep motion, and the Dzyaloshinskii-Moriya interaction in Pt/Co/Ir thin films

    Science.gov (United States)

    Shepley, Philippa M.; Tunnicliffe, Harry; Shahbazi, Kowsar; Burnell, Gavin; Moore, Thomas A.

    2018-04-01

    We study the magnetic properties of perpendicularly magnetized Pt/Co/Ir thin films and investigate the domain-wall creep method of determining the interfacial Dzyaloshinskii-Moriya (DM) interaction in ultrathin films. Measurements of the Co layer thickness dependence of saturation magnetization, perpendicular magnetic anisotropy, and symmetric and antisymmetric (i.e., DM) exchange energies in Pt/Co/Ir thin films have been made to determine the relationship between these properties. We discuss the measurement of the DM interaction by the expansion of a reverse domain in the domain-wall creep regime. We show how the creep parameters behave as a function of in-plane bias field and discuss the effects of domain-wall roughness on the measurement of the DM interaction by domain expansion. Whereas modifications to the creep law with DM field and in-plane bias fields have taken into account changes in the energy barrier scaling parameter α , we find that both α and the velocity scaling parameter v0 change as a function of in-plane bias field.

  10. All-optical switching by domain wall motion in Co/Pd superlattices with a high-repetition-rate laser

    Science.gov (United States)

    Hoveyda, Farzaneh; Hohenstein, Erich; Smadici, Serban

    All-optical switching (AOS) of magnetization with femtosecond laser pulses has been demonstrated in ferri- and ferromagnetic materials. Current models mostly correlate ultrafast reversal with the uniform rotation of magnetization. In addition, while single-pulse switching in ferrimagnets has been reported, AOS in ferromagnetic Co/Pt has also been observed with overlapping pulses. This suggests the possibility to initiate a magnetization reversal with a high repetition rate laser. In our work, ferromagnetic Co/Pd superlattices, deposited by e-beam evaporation, were scanned under a high repetition rate Ti:Sapphire laser beam. Imaging with polarizing and magnetic force microscopes confirmed that AOS was attained. Intriguingly, measurements with a chopped beam showed a few ms delay before the reversed domains become visible. These domains gradually expanded by domain wall motion. We explain the delay with heat accumulation due to the high-repetition-rate laser pulses. The heat accumulation introduces in-plane thermal gradients, which apply forces on the magnetic domain walls. This suggests a model of the observed reversal by thermally driven domain wall motion.

  11. 4D Lorentz electron microscopy imaging: magnetic domain wall nucleation, reversal, and wave velocity.

    Science.gov (United States)

    Park, Hyun Soon; Baskin, J Spencer; Zewail, Ahmed H

    2010-09-08

    Magnetization reversal is an important topic of research in the fields of both basic and applied ferromagnetism. For the study of magnetization reversal dynamics and magnetic domain wall (DW) motion in ferromagnetic thin films, imaging techniques are indispensable. Here, we report 4D imaging of DWs by the out-of-focus Fresnel method in Lorentz ultrafast electron microscopy (UEM), with in situ spatial and temporal resolutions. The temporal change in magnetization, as revealed by changes in image contrast, is clocked using an impulsive optical field to produce structural deformation of the specimen, thus modulating magnetic field components in the specimen plane. Directly visualized are DW nucleation and subsequent annihilation and oscillatory reappearance (periods of 32 and 45 ns) in nickel films on two different substrates. For the case of Ni films on a Ti/Si(3)N(4) substrate, under conditions of minimum residual external magnetic field, the oscillation is associated with a unique traveling wave train of periodic magnetization reversal. The velocity of DW propagation in this wave train is measured to be 172 m/s with a wavelength of 7.8 microm. The success of this study demonstrates the promise of Lorentz UEM for real-space imaging of spin switching, ferromagnetic resonance, and laser-induced demagnetization in ferromagnetic nanostructures.

  12. Fast domain wall motion in the vicinity of the angular momentum compensation temperature of ferrimagnets

    Science.gov (United States)

    Kim, Kab-Jin; Kim, Se Kwon; Hirata, Yuushou; Oh, Se-Hyeok; Tono, Takayuki; Kim, Duck-Ho; Okuno, Takaya; Ham, Woo Seung; Kim, Sanghoon; Go, Gyoungchoon; Tserkovnyak, Yaroslav; Tsukamoto, Arata; Moriyama, Takahiro; Lee, Kyung-Jin; Ono, Teruo

    2017-12-01

    Antiferromagnetic spintronics is an emerging research field which aims to utilize antiferromagnets as core elements in spintronic devices. A central motivation towards this direction is that antiferromagnetic spin dynamics is expected to be much faster than its ferromagnetic counterpart. Recent theories indeed predicted faster dynamics of antiferromagnetic domain walls (DWs) than ferromagnetic DWs. However, experimental investigations of antiferromagnetic spin dynamics have remained unexplored, mainly because of the magnetic field immunity of antiferromagnets. Here we show that fast field-driven antiferromagnetic spin dynamics is realized in ferrimagnets at the angular momentum compensation point TA. Using rare earth-3d-transition metal ferrimagnetic compounds where net magnetic moment is nonzero at TA, the field-driven DW mobility is remarkably enhanced up to 20 km s-1 T-1. The collective coordinate approach generalized for ferrimagnets and atomistic spin model simulations show that this remarkable enhancement is a consequence of antiferromagnetic spin dynamics at TA. Our finding allows us to investigate the physics of antiferromagnetic spin dynamics and highlights the importance of tuning of the angular momentum compensation point of ferrimagnets, which could be a key towards ferrimagnetic spintronics.

  13. An exploratory study of heavy domain wall fermions on the lattice

    CERN Document Server

    Boyle, Peter; Marinkovic, Marina Krstic; Sanfilippo, Francesco; Spraggs, Matthew; Tsang, Justus Tobias

    2016-01-01

    We report on an exploratory study of domain wall fermions (DWF) as a lattice regularisation for heavy quarks. Within the framework of quenched QCD with the tree-level improved Symanzik gauge action we identify the DWF parameters which minimise discretisation effects. We find the corresponding effective 4$d$ overlap operator to be exponentially local, independent of the quark mass. We determine a maximum bare heavy quark mass of $am_h\\approx 0.4$, below which the approximate chiral symmetry and O(a)-improvement of DWF are sustained. This threshold appears to be largely independent of the lattice spacing. Based on these findings, we carried out a detailed scaling study for the heavy-strange meson dispersion relation and decay constant on four ensembles with lattice spacings in the range $2.0-5.7\\,\\mathrm{GeV}$. We observe very mild $a^2$ scaling towards the continuum limit. Our findings establish a sound basis for heavy DWF in dynamical simulations of lattice QCD with relevance to Standard Model phenomenology.

  14. Atomic structure and domain wall pinning in samarium-cobalt-based permanent magnets.

    Science.gov (United States)

    Duerrschnabel, M; Yi, M; Uestuener, K; Liesegang, M; Katter, M; Kleebe, H-J; Xu, B; Gutfleisch, O; Molina-Luna, L

    2017-07-04

    A higher saturation magnetization obtained by an increased iron content is essential for yielding larger energy products in rare-earth Sm 2 Co 17 -type pinning-controlled permanent magnets. These are of importance for high-temperature industrial applications due to their intrinsic corrosion resistance and temperature stability. Here we present model magnets with an increased iron content based on a unique nanostructure and -chemical modification route using Fe, Cu, and Zr as dopants. The iron content controls the formation of a diamond-shaped cellular structure that dominates the density and strength of the domain wall pinning sites and thus the coercivity. Using ultra-high-resolution experimental and theoretical methods, we revealed the atomic structure of the single phases present and established a direct correlation to the macroscopic magnetic properties. With further development, this knowledge can be applied to produce samarium cobalt permanent magnets with improved magnetic performance.Understanding the factors that determine the properties of permanent magnets, which play a central role in many industrial applications, can help in improving their performance. Here, the authors study how changes in the iron content affect the microstructure of samarium cobalt magnets.

  15. Prediction and Experimental Evidence for Thermodynamically Stable Charged Orbital Domain Walls

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qing’an; Gray, K. E.; Wilkins, S. B.; Garcia Fernandez, M.; Rosenkranz, S.; Zheng, H.; Mitchell, J. F.

    2014-08-01

    The quest for miniaturization is prevalent in many fields of modern science and technology. The ultimate limit for conduction would be a one-dimensional (1D) chain of atoms and, for example, carbon nanotubes are a notable approximation to this ideal. Here we present strong evidence for an unexpected phenomenon—a sliding charge-density wave along pseudo-1D, atomically homogeneous orbital domain walls (ODWs) in insulating bilayer manganite crystals. At a threshold electric field, crystals exhibit abrupt transformations to higher conductance, while x-ray diffraction confirms that these are not due to heating or melting of charge order. The conductance data resemble those of well-known pseudo-1D sliding-charge-density waves, in particular the presence of a depinning voltage. The vital link is our theoretical insight that ODWs must be partially charged due to competition between orbital-induced strain and Coulomb repulsion. The ideas found here embody a new principle for creating ultra-nano conductive paths in other materials and devices.

  16. Exact Solution of the Six-Vertex Model with Domain Wall Boundary Conditions. Disordered Phase

    CERN Document Server

    Bleher, P M

    2005-01-01

    The six-vertex model, or the square ice model, with domain wall boundary conditions (DWBC) has been introduced and solved for finite $N$ by Korepin and Izergin. The solution is based on the Yang-Baxter equations and it represents the free energy in terms of an $N\\times N$ Hankel determinant. Paul Zinn-Justin observed that the Izergin-Korepin formula can be re-expressed in terms of the partition function of a random matrix model with a nonpolynomial interaction. We use this observation to obtain the large $N$ asymptotics of the six-vertex model with DWBC in the disordered phase. The solution is based on the Riemann-Hilbert approach and the Deift-Zhou nonlinear steepest descent method. As was noticed by Kuperberg, the problem of enumeration of alternating sign matrices (the ASM problem) is a special case of the the six-vertex model. We compare the obtained exact solution of the six-vertex model with known exact results for the 1, 2, and 3 enumerations of ASMs, and also with the exact solution on the so-called f...

  17. Manipulation of domain-wall solitons in bi- and trilayer graphene

    Science.gov (United States)

    Jiang, Lili; Wang, Sheng; Shi, Zhiwen; Jin, Chenhao; Utama, M. Iqbal Bakti; Zhao, Sihan; Shen, Yuen-Ron; Gao, Hong-Jun; Zhang, Guangyu; Wang, Feng

    2018-01-01

    Topological dislocations and stacking faults greatly affect the performance of functional crystalline materials1-3. Layer-stacking domain walls (DWs) in graphene alter its electronic properties and give rise to fascinating new physics such as quantum valley Hall edge states4-10. Extensive efforts have been dedicated to the engineering of dislocations to obtain materials with advanced properties. However, the manipulation of individual dislocations to precisely control the local structure and local properties of bulk material remains an outstanding challenge. Here we report the manipulation of individual layer-stacking DWs in bi- and trilayer graphene by means of a local mechanical force exerted by an atomic force microscope tip. We demonstrate experimentally the capability to move, erase and split individual DWs as well as annihilate or create closed-loop DWs. We further show that the DW motion is highly anisotropic, offering a simple approach to create solitons with designed atomic structures. Most artificially created DW structures are found to be stable at room temperature.

  18. A novel and highly specific phage endolysin cell wall binding domain for detection of Bacillus cereus.

    Science.gov (United States)

    Kong, Minsuk; Sim, Jieun; Kang, Taejoon; Nguyen, Hoang Hiep; Park, Hyun Kyu; Chung, Bong Hyun; Ryu, Sangryeol

    2015-09-01

    Rapid, specific and sensitive detection of pathogenic bacteria is crucial for public health and safety. Bacillus cereus is harmful as it causes foodborne illness and a number of systemic and local infections. We report a novel phage endolysin cell wall-binding domain (CBD) for B. cereus and the development of a highly specific and sensitive surface plasmon resonance (SPR)-based B. cereus detection method using the CBD. The newly discovered CBD from endolysin of PBC1, a B. cereus-specific bacteriophage, provides high specificity and binding capacity to B. cereus. By using the CBD-modified SPR chips, B. cereus can be detected at the range of 10(5)-10(8) CFU/ml. More importantly, the detection limit can be improved to 10(2) CFU/ml by using a subtractive inhibition assay based on the pre-incubation of B. cereus and CBDs, removal of CBD-bound B. cereus, and SPR detection of the unbound CBDs. The present study suggests that the small and genetically engineered CBDs can be promising biological probes for B. cereus. We anticipate that the CBD-based SPR-sensing methods will be useful for the sensitive, selective, and rapid detection of B. cereus.

  19. Spin Hall driven domain wall motion in magnetic bilayers coupled by a magnetic oxide interlayer

    Science.gov (United States)

    Liu, Yang; Furuta, Masaki; Zhu, Jian-Gang Jimmy

    2018-05-01

    mCell, previously proposed by our group, is a four-terminal magnetoresistive device with isolated write- and read-paths for all-spin logic and memory applications. A mCell requires an electric-insulating magnetic layer to couple the spin Hall driven write-path to the magnetic free layer of the read-path. Both paths are magnetic layers with perpendicular anisotropy and their perpendicularly oriented magnetization needs to be maintained with this insertion layer. We have developed a magnetic oxide (FeOx) insertion layer to serve for these purposes. We show that the FeOx insertion layer provides sufficient magnetic coupling between adjacent perpendicular magnetic layers. Resistance measurement shows that this magnetic oxide layer can act as an electric-insulating layer. In addition, spin Hall driven domain wall motion in magnetic bi-layers coupled by the FeOx insertion layer is significantly enhanced compared to that in magnetic single layer; it also requires low voltage threshold that poses possibility for power-efficient device applications.

  20. Dramatic effect of curvature on DW velocity in chiral domain walls

    Science.gov (United States)

    Garg, Chirag; Yang, See-Hun; Phung, Timothy; Pushp, Aakash; Parkin, Stuart S. P.; Magnetoelectronics Group, IBM Almaden Team

    The use of current pulses to manipulate domain walls (DWs) in nanowires is one of the most exciting developments in spintronics over the past decade, promising a range of novel devices. However, even after more than 10 years of work on current induced DW motion it has not been realized that the curvature of the nanowire can affect the speed of chiral DWs. Here we show that simply changing the sign of the curvature of a nanowire, dramatically changes the speed of Néel DWs in perpendicularly magnetized nanowires, by up to a factor of 10. We find that, DWs have an increased or decreased velocity in wires of a given curvature, independent of the DW chirality and the sign of the current induced torques. The fundamental origin of this effect is due to a current induced tilting of the DW that breaks the symmetry of the DW's motion with respect to the curvature of the wire. Whilst the strong dependence of the DW velocity on the nanowire's curvature may offer added device functionalities, we find that in synthetic antiferromagnetic nanowires, the influence of the curvature on the DW's velocity can be completely removed.

  1. Spin-orbit torques for current parallel and perpendicular to a domain wall

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Tomek; Lee, Kyujoon; Karnad, Gurucharan V. [Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, 55128 Mainz (Germany); Alejos, Oscar [Departamento de Electricidad y Electrónica, Universidad de Valladolid, Paseo de Belen, 7, E-47011 Valladolid (Spain); Martinez, Eduardo; Moretti, Simone [Departamento Fisica Aplicada, Universidad de Salamanca, Plaza de los Caidos s/n, E-38008 Salamanca (Spain); Hals, Kjetil M. D. [Niels Bohr International Academy and the Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Garcia, Karin; Ravelosona, Dafiné [Institut d' Electronique Fondamentale, UMR CNRS 8622, Université Paris Sud, 91405 Orsay Cedex (France); Vila, Laurent [Institut Nanosciences et Cryogénie, Université Grenoble Alpes, F-38000 Grenoble (France); Institut Nanosciences et Cryogénie, CEA, F-38000 Grenoble (France); Lo Conte, Roberto; Kläui, Mathias [Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, 55128 Mainz (Germany); Graduate School of Excellence “Materials Science in Mainz” (MAINZ), Staudinger Weg 9, 55128 Mainz (Germany); Ocker, Berthold [Singulus Technologies AG, 63796 Kahl am Main (Germany); Brataas, Arne [Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

    2015-09-21

    We report field- and current-induced domain wall (DW) depinning experiments in Ta\\Co{sub 20}Fe{sub 60}B{sub 20}\\MgO nanowires through a Hall cross geometry. While purely field-induced depinning shows no angular dependence on in-plane fields, the effect of the current depends crucially on the internal DW structure, which we manipulate by an external magnetic in-plane field. We show depinning measurements for a current sent parallel to the DW and compare its depinning efficiency with the conventional case of current flowing perpendicularly to the DW. We find that the maximum efficiency is similar for both current directions within the error bars, which is in line with a dominating damping-like spin-orbit torque (SOT) and indicates that no large additional torques arise for currents perpendicular to the DW. Finally, we find a varying dependence of the maximum depinning efficiency angle for different DWs and pinning levels. This emphasizes the importance of our full angular scans compared with previously used measurements for just two field directions (parallel and perpendicular to the DW) to determine the real torque strength and shows the sensitivity of the SOT to the precise DW structure and pinning sites.

  2. Interlocked chiral/polar domain walls and large optical rotation in Ni3TeO6

    Directory of Open Access Journals (Sweden)

    Xueyun Wang

    2015-07-01

    Full Text Available Chirality, i.e., handedness, pervades much of modern science from elementary particles, DNA-based biology to molecular chemistry; however, most of the chirality-relevant materials have been based on complex molecules. Here, we report inorganic single-crystalline Ni3TeO6, forming in a corundum-related R3 structure with both chirality and polarity. These chiral Ni3TeO6 single crystals exhibit a large optical specific rotation (α—1355° dm−1 cm3 g−1. We demonstrate, for the first time, that in Ni3TeO6, chiral and polar domains form an intriguing domain pattern, resembling a radiation warning sign, which stems from interlocked chiral and polar domain walls through lowering of the wall energy.

  3. Spherical domain wall formed by field dynamics of Hawking radiation and spontaneous charging-up of black hole

    International Nuclear Information System (INIS)

    Nagatani, Yukinori

    2004-01-01

    We investigate the Hawking radiation in the gauge Higgs-Yukawa theory. The ballistic model is proposed as an effective description of the system. We find that a spherical domain wall around the black hole is formed by field dynamics rather than thermal phase transition. The formation is a general property of the black hole whose Hawking temperature is equal to or greater than the energy scale of the theory. The formation of the electroweak wall and that of the GUT wall are shown. We also find a phenomenon of the spontaneous charging-up of the black hole by the wall. The Hawking radiation drives a mechanism of the charge transportation into the black hole when C- and CP-violation are assumed. The mechanism can strongly transport the hyper-charge into a black hole of the electroweak scale

  4. Hysteresis modelling of GO laminations for arbitrary in-plane directions taking into account the dynamics of orthogonal domain walls

    Energy Technology Data Exchange (ETDEWEB)

    Baghel, A.P.S.; Sai Ram, B. [Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India); Chwastek, K. [Department of Electrical Engineering Czestochowa University of Technology (Poland); Daniel, L. [Group of Electrical Engineering-Paris (GeePs), CNRS(UMR8507)/CentraleSupelec/UPMC/Univ Paris-Sud, 11 rue Joliot-Curie, 91192 Gif-sur-Yvette (France); Kulkarni, S.V. [Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India)

    2016-11-15

    The anisotropy of magnetic properties in grain-oriented steels is related to their microstructure. It results from the anisotropy of the single crystal properties combined to crystallographic texture. The magnetization process along arbitrary directions can be explained using phase equilibrium for domain patterns, which can be described using Neel's phase theory. According to the theory the fractions of 180° and 90° domain walls depend on the direction of magnetization. This paper presents an approach to model hysteresis loops of grain-oriented steels along arbitrary in-plane directions. The considered description is based on a modification of the Jiles–Atherton model. It includes a modified expression for the anhysteretic magnetization which takes into account contributions of two types of domain walls. The computed hysteresis curves for different directions are in good agreement with experimental results. - Highlights: • An extended Jiles–Atherton description is used to model hysteresis loops in GO steels. • The model stresses the role of material anisotropy and different contributions of the two types of domain walls. • Hysteresis loops can be modeled along arbitrary in-plane directions. • Modeling results are in good agreement with experiments.

  5. Towards a more analytic understanding of the pinning of domain walls in high-temperature permanent magnets

    CERN Document Server

    Chui, S T

    2000-01-01

    We discuss analytic results for the depinning of domain walls based on different models for wall pinning in permanent magnets. We propose an explanation for the different temperature dependences of the coercive field for repulsive and attractive pinning potential when the pinning boundary forms an array of pyramids and suggest that the switching dynamics are different in the two regimes. This may be tested experimentally by magnetic viscosity measurements on samples with different Cu contents. We also found analytically that when the pinning boundary forms an array of cubes, the coercive field always decreases no matter whether the pinning potential is repulsive or attractive. This is confirmed by Monte Carlo simulations.

  6. Field driven ferromagnetic phase nucleation and propagation from the domain boundaries in antiferromagnetically coupled perpendicular anisotropy films

    Energy Technology Data Exchange (ETDEWEB)

    Hauet, Thomas; Gunther, Christian M.; Hovorka, Ondrej; Berger, Andreas; Im, Mi-Young; Fischer, Peter; Hellwig, Olav

    2008-12-09

    We investigate the reversal process in antiferromagnetically coupled [Co/Pt]{sub X-1}/{l_brace}Co/Ru/[Co/Pt]{sub X-1}{r_brace}{sub 16} multilayer films by combining magnetometry and Magnetic soft X-ray Transmission Microscopy (MXTM). After out-of-plane demagnetization, a stable one dimensional ferromagnetic (FM) stripe domain phase (tiger-tail phase) for a thick stack sample (X=7 is obtained), while metastable sharp antiferromagnetic (AF) domain walls are observed in the remanent state for a thinner stack sample (X=6). When applying an external magnetic field the sharp domain walls of the thinner stack sample transform at a certain threshold field into the FM stripe domain wall phase. We present magnetic energy calculations that reveal the underlying energetics driving the overall reversal mechanisms.

  7. Nucleon structure in lattice QCD with dynamical domain-wall fermions quarks

    International Nuclear Information System (INIS)

    Huey-Wen Lin; Shigemi Ohta

    2006-01-01

    We report RBC and RBC/UKQCD lattice QCD numerical calculations of nucleon electroweak matrix elements with dynamical domain-wall fermions (DWF) quarks. The first, RBC, set of dynamical DWF ensembles employs two degenerate flavors of DWF quarks and the DBW2 gauge action. Three sea quark mass values of 0.04, 0.03 and 0.02 in lattice units are used with about 200 gauge configurations each. The lattice cutoff is about 1.7 GeV and the spatial volume is about (1.9 fm) 3 . Despite the small volume, the ratio of the isovector vector and axial charges g A /g V and that of structure function moments u-d / Δ u-Δ d are in agreement with experiment, and show only very mild quark mass dependence. The second, RBC/UK, set of ensembles employs one strange and two degenerate (up and down) dynamical DWF quarks and Iwasaki gauge action. The strange quark mass is set at 0.04, and three up/down mass values of 0.03, 0.02 and 0.01 in lattice units are used. The lattice cutoff is about 1.6 GeV and the spatial volume is about (3.0 fm) 3 . Even with preliminary statistics of 25-30 gauge configurations, the ratios g A /g V and u-d / Δu - Δd are consistent with experiment and show only very mild quark mass dependence. Another structure function moment, d 1 , though yet to be renormalized, appears small in both sets

  8. NUCLEON STRUCTURE IN LATTICE QCD WITH DYNAMICAL DOMAIN--WALL FERMIONS QUARKS

    International Nuclear Information System (INIS)

    LIN, H.W.; OHTA, S.

    2006-01-01

    We report RBC and RBC/UKQCD lattice QCD numerical calculations of nucleon electroweak matrix elements with dynamical domain-wall fermions (DWF) quarks. The first, RBC, set of dynamical DWF ensembles employs two degenerate flavors of DWF quarks and the DBW2 gauge action. Three sea quark mass values of 0.04, 0.03 and 0.02 in lattice units are used with 220 gauge configurations each. The lattice cutoff is a -1 ∼ 1.7GeV and the spatial volume is about (1.9fm) 3 . Despite the small volume, the ratio of the isovector vector and axial charges g A /g V and that of structure function moments u-d / Δu-Δd are in agreement with experiment, and show only very mild quark mass dependence. The second, RBC/UK, set of ensembles employs one strange and two degenerate (up and down) dynamical DWF quarks and Iwasaki gauge action. The strange quark mass is set at 0.04, and three up/down mass values of 0.03, 0.02 and 0.01 in lattice units are used. The lattice cutoff is a -1 ∼ 1.6GeV and the spatial volume is about (3.0fm) 3 . Even with preliminary statistics of 25-30 gauge configurations, the ratios g A /g V and u-d / Δu-Δd are consistent with experiment and show only very mild quark mass dependence. Another structure function moment, d 1 , though yet to be renormalized, appears small in both sets

  9. Time evolution of one-dimensional gapless models from a domain wall initial state: stochastic Loewner evolution continued?

    International Nuclear Information System (INIS)

    Calabrese, Pasquale; Hagendorf, Christian; Doussal, Pierre Le

    2008-01-01

    We study the time evolution of quantum one-dimensional gapless systems evolving from initial states with a domain wall. We generalize the path integral imaginary time approach that together with boundary conformal field theory allows us to derive the time and space dependence of general correlation functions. The latter are explicitly obtained for the Ising universality class, and the typical behavior of one- and two-point functions is derived for the general case. Possible connections with the stochastic Loewner evolution are discussed and explicit results for one-point time dependent averages are obtained for generic κ for boundary conditions corresponding to stochastic Loewner evolution. We use this set of results to predict the time evolution of the entanglement entropy and obtain the universal constant shift due to the presence of a domain wall in the initial state

  10. Identification of defect distribution at ferroelectric domain walls from evolution of nonlinear dielectric response during the aging process

    Czech Academy of Sciences Publication Activity Database

    Mokrý, Pavel; Sluka, T.

    2016-01-01

    Roč. 93, č. 6 (2016), č. článku 064114. ISSN 2469-9950 R&D Projects: GA ČR(CZ) GA14-32228S Institutional support: RVO:61389021 Keywords : Nonlinear dielectric response * ferroelectric domain walls * aging process * phase field simulations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.836, year: 2016 http://journals.aps.org/prb/abstract/10.1103/PhysRevB.93.064114

  11. Nucleon structure from mixed action calculations using 2+1 flavors of asqtad sea and domain wall valence fermions

    CERN Document Server

    Bratt, J.D.; Engelhardt, M.; Hagler, Ph.; Lin, H.W.; Lin, M.F.; Meyer, H.B.; Musch, B.; Negele, J.W.; Orginos, K.; Pochinsky, A.V.; Procura, M.; Richards, D.G.; Schroers, W.; Syritsyn, S.N.

    2010-01-01

    We present high statistics results for the structure of the nucleon from a mixed-action calculation using 2+1 flavors of asqtad sea and domain wall valence fermions. We perform extrapolations of our data based on different chiral effective field theory schemes and compare our results with available information from phenomenology. We discuss vector and axial form factors of the nucleon, moments of generalized parton distributions, including moments of forward parton distributions, and implications for the decomposition of the nucleon spin.

  12. Stress-induced phase transition in ferroelectric domain walls of BaTiO.sub.3./sub

    Czech Academy of Sciences Publication Activity Database

    Stepkova, Vilgelmina; Márton, Pavel; Hlinka, Jiří

    2012-01-01

    Roč. 24, č. 21 (2012), 1-4 ISSN 0953-8984 R&D Projects: GA ČR GAP204/10/0616 Institutional research plan: CEZ:AV0Z10100520 Keywords : phase transition * ferroelectric domain walls * BaTiO 3 * rhombohedral * phase-field simulations * epitaxial stress * chiral Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.355, year: 2012

  13. Nucleon structure from mixed action calculations using 2+1 flavors of asqtad sea and domain wall valence fermions

    Energy Technology Data Exchange (ETDEWEB)

    Bratt, Jonathan; Engelhardt, Michael; Haegler, Philipp; Huey-Wen, Lin; Lin, Meifeng; Meyer, Harvey; Musch, Bernhard; Negele, John; Orginos, Konstantinos; Pochinsky, Andrew; Procura, Massimiliano; Richards, David; Schroers, Wolfram; Syritsyn, Sergey

    2010-11-01

    We present high statistics results for the structure of the nucleon from a mixed-action calculation using 2+1 flavors of asqtad sea and domain wall valence fermions. We perform extrapolations of our data based on different chiral effective field theory schemes and compare our results with available information from phenomenology. We discuss vector and axial form factors of the nucleon, moments of generalized parton distributions, including moments of forward parton distributions, and implications for the decomposition of the nucleon spin.

  14. Characterization of a novel cell wall binding domain-containing Staphylococcus aureus endolysin LysSA97.

    Science.gov (United States)

    Chang, Yoonjee; Ryu, Sangryeol

    2017-01-01

    Endolysin from Staphylococcus aureus phage SA97 (LysSA97) was cloned and investigated. LysSA97 specifically lyse the staphylococcal strains and effectively disrupted staphylococcal biofilms. Bioinformatic analysis of LysSA97 revealed a novel putative cell wall binding domain (CBD) as well as two enzymatically active domains (EADs) containing cysteine, histidine-dependent amidohydrolases/peptidases (CHAP, PF05257) and N-acetylmuramoyl-L-alanine amidase (Amidase-3, PF01520) domains. Comparison of 98 endolysin genes of S. aureus phages deposited in GenBank showed that they can be classified into six groups based on their domain composition. Interestingly, approximately 80.61 % of the staphylococcal endolysins have a src-homology 3 (SH3, PF08460) domain as CBD, but the remaining 19.39 %, including LysSA97, has a putative C-terminal CBD with no homology to the known CBD. The fusion protein containing green fluorescent protein and the putative CBD of LysSA97 showed a specific binding spectrum against staphylococcal cells comparable to SH3 domain (PF08460), suggesting that the C-terminal domain of LysSA97 is a novel CBD of staphylococcal endolysins.

  15. Murein and pseudomurein cell wall binding domains of bacteria and archaea-a comparative view

    NARCIS (Netherlands)

    Visweswaran, Ganesh Ram R.; Dijkstra, Bauke W.; Kok, Jan

    2011-01-01

    The cell wall, a major barrier protecting cells from their environment, is an essential compartment of both bacteria and archaea. It protects the organism from internal turgor pressure and gives a defined shape to the cell. The cell wall serves also as an anchoring surface for various proteins and

  16. Distinct Nature of Static and Dynamic Magnetic Stripes in Cuprate Superconductors

    Science.gov (United States)

    Jacobsen, H.; Holm, S. L.; Lǎcǎtuşu, M.-E.; Rømer, A. T.; Bertelsen, M.; Boehm, M.; Toft-Petersen, R.; Grivel, J.-C.; Emery, S. B.; Udby, L.; Wells, B. O.; Lefmann, K.

    2018-01-01

    We present detailed neutron scattering studies of the static and dynamic stripes in an optimally doped high-temperature superconductor, La2 CuO4 +y . We observe that the dynamic stripes do not disperse towards the static stripes in the limit of vanishing energy transfer. Therefore, the dynamic stripes observed in neutron scattering experiments are not the Goldstone modes associated with the broken symmetry of the simultaneously observed static stripes, and the signals originate from different domains in the sample. These observations support real-space electronic phase separation in the crystal, where the static stripes in one phase are pinned versions of the dynamic stripes in the other, having slightly different periods. Our results explain earlier observations of unusual dispersions in underdoped La2 -xSrx CuO4 (x =0.07 ) and La2 -xBax CuO4 (x =0.095 ).

  17. Distinct Nature of Static and Dynamic Magnetic Stripes in Cuprate Superconductors

    DEFF Research Database (Denmark)

    Jacobsen, H.; Holm, S. L.; Lăcătuşu, M. E.

    2018-01-01

    We present detailed neutron scattering studies of the static and dynamic stripes in an optimally doped high-Temperature superconductor, La2CuO4+y. We observe that the dynamic stripes do not disperse towards the static stripes in the limit of vanishing energy transfer. Therefore, the dynamic stripes...... observed in neutron scattering experiments are not the Goldstone modes associated with the broken symmetry of the simultaneously observed static stripes, and the signals originate from different domains in the sample. These observations support real-space electronic phase separation in the crystal, where...... the static stripes in one phase are pinned versions of the dynamic stripes in the other, having slightly different periods. Our results explain earlier observations of unusual dispersions in underdoped La2-xSrxCuO4 (x=0.07) and La2-xBaxCuO4 (x=0.095)....

  18. Domain configuration and magnetization switching in arrays of permalloy nanostripes

    International Nuclear Information System (INIS)

    Iglesias-Freire, Ó.; Jaafar, M.; Pérez, L.; Abril, O. de; Vázquez, M.; Asenjo, A.

    2014-01-01

    The proximity effect in the collective behavior of arrays of magnetic nanostripes is currently a subject of intensive research. The imperative of reducing the size and distances between elements in order to achieve higher storage capacity, faster access to the information as well as low energy consumption, brings consequences about the isolated behavior of the elements and devices. Parallel to each other permalloy nanostripes with high aspect ratio have been prepared by the nanolithography technique. The evolution of the closure domains and the magnetization direction in individual nanostructures has been imaged under applied magnetic fields using Variable Field Magnetic Force Microscopy. Moreover, the magnetostatic interactions between neighboring elements and the proximity effects in arrays of such nanostructures have been quantitatively analyzed by Magnetic Force Microscopy and micromagnetic simulations. The agreement between simulations and the experimental results allows us to conclude the relevance of those interactions depending on the geometry characteristics. In particular, results suggest that the magnetostatic coupling between adjacent nanostripes vanishes for separation distances higher than 500 nm. - Highlights: • A shape anisotropy-induced single domain remanent state is present in the stripes. Closure domains are formed under external fields. • Separation distances between neighboring stripes (500 nm) are enough to overcome the magnetostatic coupling and avoid a multi-stripe character. • Micromagnetic simulations predict critical distances of around 500 nm for the onset of magnetostatic coupling between neighboring elements. • Simulations predict stripes with a small longitudinal separation to behave as single elements, with domain walls “jumping” between them

  19. Domain configuration and magnetization switching in arrays of permalloy nanostripes

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias-Freire, Ó., E-mail: aasenjo@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, Madrid 28049 (Spain); Jaafar, M. [Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, Madrid 28049 (Spain); Dpto. Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco 28049 (Spain); Pérez, L. [Dpto. Física de Materiales, Universidad Complutense de Madrid, Madrid 28040 (Spain); Abril, O. de [Dpto. Física e Instalaciones Aplicadas a la Edificación, al Medio Ambiente y al Urbanismo, Universidad Politécnica de Madrid, Madrid 28040 (Spain); Vázquez, M.; Asenjo, A. [Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, Madrid 28049 (Spain)

    2014-04-15

    The proximity effect in the collective behavior of arrays of magnetic nanostripes is currently a subject of intensive research. The imperative of reducing the size and distances between elements in order to achieve higher storage capacity, faster access to the information as well as low energy consumption, brings consequences about the isolated behavior of the elements and devices. Parallel to each other permalloy nanostripes with high aspect ratio have been prepared by the nanolithography technique. The evolution of the closure domains and the magnetization direction in individual nanostructures has been imaged under applied magnetic fields using Variable Field Magnetic Force Microscopy. Moreover, the magnetostatic interactions between neighboring elements and the proximity effects in arrays of such nanostructures have been quantitatively analyzed by Magnetic Force Microscopy and micromagnetic simulations. The agreement between simulations and the experimental results allows us to conclude the relevance of those interactions depending on the geometry characteristics. In particular, results suggest that the magnetostatic coupling between adjacent nanostripes vanishes for separation distances higher than 500 nm. - Highlights: • A shape anisotropy-induced single domain remanent state is present in the stripes. Closure domains are formed under external fields. • Separation distances between neighboring stripes (500 nm) are enough to overcome the magnetostatic coupling and avoid a multi-stripe character. • Micromagnetic simulations predict critical distances of around 500 nm for the onset of magnetostatic coupling between neighboring elements. • Simulations predict stripes with a small longitudinal separation to behave as single elements, with domain walls “jumping” between them.

  20. A minimum of three motifs is essential for optimal binding of pseudomurein cell wall-binding domain of Methanothermobacter thermautotrophicus.

    Directory of Open Access Journals (Sweden)

    Ganesh Ram R Visweswaran

    Full Text Available We have biochemically and functionally characterized the pseudomurein cell wall-binding (PMB domain that is present at the C-terminus of the Surface (S-layer protein MTH719 from Methanothermobacter thermautotrophicus. Chemical denaturation of the protein with guanidinium hydrochloride occurred at 3.8 M. A PMB-GFP fusion protein not only binds to intact pseudomurein of methanogenic archaea, but also to spheroplasts of lysozyme-treated bacterial cells. This binding is pH dependent. At least two of the three motifs that are present in the domain are necessary for binding. Limited proteolysis revealed a possible cleavage site in the spacing sequence between motifs 1 and 2 of the PMB domain, indicating that the motif region itself is protected from proteases.

  1. Wheat Stripe Rust

    OpenAIRE

    Pace, Mike; Israelsen, Clark; Evans, Kent; Barnhill, James

    2008-01-01

    Stripe rust, or yellow rust, is primarily a foliar fungal disease of wheat, although it can infect spike and stem tissues. If the pathogen infects the spike (head) it causes extensive quality and grain yield loss. The disease is caused by the fungus Puccinia striiformis f. sp. tritici. The fungus can only survive and reproduce on wheat. It survives from one season to the next on volunteer plants.

  2. An investigation of domains and walls in two NdFeB alloys by transmission electron microscopy

    International Nuclear Information System (INIS)

    Young, S.; Chapman, J.N.

    1993-01-01

    Transmission Electron Microscopy (TEM) has been used to investigate the domain structure in NdFeB alloy ampersand The variation of domain period in thinned sections has been studied for two different alloys and an energy minimization model has been used to calculate the specific domain wall energy (σ) for each alloy. For the basic alloy (A) a value for σ of 20.4mJ/m 2 Was found, whilst the alloy with additions of Dy (B) had a value which was ∼10% lower. This apparently surprising result is attributed to a decrease in the RE-TM exchange energy which more than offsets the increase in anisotropy resulting from the addition of Dy. The behavior of domains as they approach a grain boundary has also been investigated. It has been observed that the relative orientation of the c-axes of two adjacent grains is extremely important in determining the behavior of the domain structure at the grain boundary

  3. Cell wall domain and moisture content influence southern pine electrical conductivity

    Science.gov (United States)

    Samuel L. Zelinka; Leandro Passarini; José L. Colon Quintana; Samuel V. Glass; Joseph E. Jakes; Alex C. Wiedenhoeft

    2016-01-01

    Recent work has highlighted the importance of movement of chemicals and ions through the wood cell wall. This movement depends strongly on moisture content and is necessary for structural damage mechanisms such as fastener corrosion and wood decay. Here, we present the first measurements of electrical resistance of southern pine at the subcellular level as a function...

  4. Nucleon transverse momentum-dependent parton distributions from domain wall fermion calculations at 297 MeV pion mass

    Energy Technology Data Exchange (ETDEWEB)

    Engelhardt, Michael; Musch, Bernhard; Bhattacharya, Tanmoy; Gupta, Rajan; Hagler, Phillip; Negele, John; Pochinsky, Andrew; Shafer, Andreas; Syritsyn, Sergey; Yoon, Boram

    2014-12-01

    Lattice QCD calculations of transverse momentum-dependent parton distributions (TMDs) in a nucleon are performed based on a definition of TMDs via hadronic matrix elements of quark bilocal operators containing staple-shaped gauge connections. A parametrization of the matrix elements in terms of invariant amplitudes serves to cast them in the Lorentz frame preferred for the lattice calculation. Using a RBC/UKQCD domain wall fermion ensemble corresponding to a pion mass of 297MeV, on a lattice with spacing 0.084fm, selected TMD observables are accessed and compared to previous explorations at heavier pion masses on coarser lattices.

  5. Ferroelectricity driven magnetism at domain walls in LaAlO3/PbTiO3 superlattices

    Science.gov (United States)

    Zhou, P. X.; Dong, S.; Liu, H. M.; Ma, C. Y.; Yan, Z. B.; Zhong, C. G.; Liu, J. -M.

    2015-01-01

    Charge dipole moment and spin moment rarely coexist in single-phase bulk materials except in some multiferroics. Despite the progress in the past decade, for most multiferroics their magnetoelectric performance remains poor due to the intrinsic exclusion between charge dipole and spin moment. As an alternative approach, the oxide heterostructures may evade the intrinsic limits in bulk materials and provide more attractive potential to realize the magnetoelectric functions. Here we perform a first-principles study on LaAlO3/PbTiO3 superlattices. Although neither of the components is magnetic, magnetic moments emerge at the ferroelectric domain walls of PbTiO3 in these superlattices. Such a twist between ferroelectric domain and local magnetic moment, not only manifests an interesting type of multiferroicity, but also is possible useful to pursuit the electrical-control of magnetism in nanoscale heterostructures. PMID:26269322

  6. Birth, growth and death of an antivortex during the propagation of a transverse domain wall in magnetic nanostrips

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, H.Y. [Physics Department, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); HKUST Shenzhen Research Institute, Shenzhen 518057 (China); Wang, X.R., E-mail: phxwan@ust.hk [Physics Department, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); HKUST Shenzhen Research Institute, Shenzhen 518057 (China)

    2014-11-15

    Antivortex birth, growth and death accompanying the propagation of a transverse domain wall (DW) in magnetic nanostrips are observed and analyzed. Antivortex formation is an intrinsic process of a strawberry-like transverse DW originated from magnetostatic interaction. Under an external magnetic field, the wider width region of a DW tends to move faster than the narrower one. This speed mismatch tilts and elongates DW center line. As a result, an antivortex with a well-defined polarity is periodically born near the tail of the DW center line. The antivortex either moves along the center line and dies on the other side of the nanostrip, or grows to its maximum size, detaches itself from the DW, and vanishes eventually. The former route reverses the polarity of DW while the later keeps the DW polarity unchanged. The evolution of the DW structures is analyzed using winding numbers assigned to each topological defects. The phase diagram in the field-width plane is obtained and the damping constant's influence on the phase diagram is discussed. - Highlights: • The magnetostatic interaction leads to a strawberry-like domain wall. • Two types of antivortices evolutions are identified. • Antivortex generation can cause decrease of Walker breakdown field. • The phase diagrams on the field-width plane are obtained.

  7. Role of flexoelectric coupling in polarization rotations at the a-c domain walls in ferroelectric perovskites

    Science.gov (United States)

    Cao, Ye; Chen, Long-Qing; Kalinin, Sergei V.

    2017-05-01

    Ferroelectric and ferroelastic domain walls play important roles in ferroelectric properties. However, their couplings with flexoelectricity have been less understood. In this work, we applied phase-field simulation to investigate the flexoelectric coupling with ferroelectric a/c twin structures in lead ziconate titanate thin films. Local stress gradients were found to exist near twin walls that created both lateral and vertical electric fields through the flexoelectric effect, resulting in polarization inclinations from either horizontal or normal orientation, polarization rotation angles deviated from 90°, and consequently highly asymmetric a/c twin walls. By tuning the flexoelectric strengths in a reasonable range from first-principles calculations, we found that the transverse flexoelectric coefficient has a larger influence on the polarization rotation than longitudinal and shear coefficients. As polar rotations that commonly occur at compositional morphotropic phase boundaries contribute to the piezoelectric enhancement, this work calls for further exploration of alternative strain-engineered polar rotations via flexoelectricity in ferroelectric thin films.

  8. Lighting up superconducting stripes

    Science.gov (United States)

    Ergeçen, Emre; Gedik, Nuh

    2018-02-01

    Cuprate superconductors display a plethora of complex phases as a function of temperature and carrier concentration, the understanding of which could provide clues into the mechanism of superconductivity. For example, when about one-eighth of the conduction electrons are removed from the copper oxygen planes in cuprates such as La2‑xBaxCuO4 (LBCO), the doped holes (missing electrons) organize into one-dimensional stripes (1). The bulk superconducting transition temperature (Tc) is greatly reduced, and just above Tc, electrical transport perpendicular to the planes (along the c axis) becomes resistive, but parallel to the copper oxygen planes, resistivity remains zero for a range of temperatures (2). It was proposed a decade ago (3) that this anisotropic behavior is caused by pair density waves (PDWs); superconducting Cooper pairs exist along the stripes within the planes but cannot tunnel to the adjacent layers. On page 575 of this issue, Rajasekaran et al. (4) now report detection of this state in LBCO using nonlinear reflection of high-intensity terahertz (THz) light.

  9. A New Boundary Model for Simulating Complex and Flexible Wall Bounded Domain in Dissipative Particle Dynamics

    Directory of Open Access Journals (Sweden)

    Saeid Mokhtarian

    2014-01-01

    Full Text Available Despite extensive area of applications, simulation of complex wall bounded problems or any deformable boundary is still a challenge in a Dissipative Particle Dynamics simulation. This limitation is rooted in the soft force nature of DPD and the fact that we need to use an antipenetration model for escaped particles. In the present paper, we propose a new model of antipenetration which preserves the conservation of linear momentum on the boundaries and enables us to simulate complex and flexible boundaries. Finally by performing numerical simulations, we demonstrate the validity of our new model.

  10. Depinning of the transverse domain wall trapped at magnetic impurities patterned in planar nanowires: Control of the wall motion using low-intensity and short-duration current pulses

    Science.gov (United States)

    Paixão, E. L. M.; Toscano, D.; Gomes, J. C. S.; Monteiro, M. G.; Sato, F.; Leonel, S. A.; Coura, P. Z.

    2018-04-01

    Understanding and controlling of domain wall motion in magnetic nanowires is extremely important for the development and production of many spintronic devices. It is well known that notches are able to pin domain walls, but their pinning potential strength are too strong and it demands high-intensity current pulses to achieve wall depinning in magnetic nanowires. However, traps of pinning can be also originated from magnetic impurities, consisting of located variations of the nanowire's magnetic properties, such as exchange stiffness constant, saturation magnetization, anisotropy constant, damping parameter, and so on. In this work, we have performed micromagnetic simulations to investigate the depinning mechanism of a transverse domain wall (TDW) trapped at an artificial magnetic defect using spin-polarized current pulses. In order to create pinning traps, a simplified magnetic impurity model, only based on a local reduction of the exchange stiffness constant, have been considered. In order to provide a background for experimental studies, we have varied the parameter related to the pinning potential strength of the magnetic impurity. By adjusting the pinning potential of magnetic impurities and choosing simultaneously a suitable current pulse, we have found that it is possible to obtain domain wall depinning by applying low-intensity and short-duration current pulses. Furthermore, it was considered a planar magnetic nanowire containing a linear distribution of equally-spaced magnetic impurities and we have demonstrated the position control of a single TDW by applying sequential current pulses; that means the wall movement from an impurity to another.

  11. Peculiarities of low-frequency dielectric spectra and domain wall motion in gadolinium molybdate

    International Nuclear Information System (INIS)

    Galiyarova, N.M.; Gorin, S.V.; Dontsova, L.I.; Shil'nikov, A.V.; Shuvalov, L.A.

    1994-01-01

    Low-frequency Debye dispersion of dielectric permeability in GMO with the low values of high-frequency limit ε ∞ was investigated in a wide temperature range as well as in fields of variable amplitude. The features of domain boundaries motion were studied at the partial repolarization in monopolar P-pulsed fields. The model of cooperationrelaxation motion brifing in parallel with positive to negative contribution to polarization that explained the low values of ε ∞ was suggested

  12. Resistance spikes and domain wall loops in Ising quantum Hall ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; MacDonald, A. H.

    2001-01-01

    Roč. 87, č. 21 (2001), s. 236801-1 - 216501-4 ISSN 0031-9007 R&D Projects: GA MŠk OC P5.10; GA ČR GA202/01/0754 Institutional research plan: CEZ:AV0Z1010914 Keywords : quantum Hall ferromagnet * domains Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 6.668, year: 2001

  13. Ferroelectric Domain Walls in BaTiO_3: Fingerprints in XRPD Diagrams and Quantitative HRTEM Image Analysis

    Science.gov (United States)

    Floquet, N.; Valot, C. M.; Mesnier, M. T.; Niepce, J. C.; Normand, L.; Thorel, A.; Kilaas, R.

    1997-06-01

    The structure of ferroelectric domain walls in BaTiO3 has been investigated through two complementary approaches, a global one by the fine analysis of X-ray diffraction patterns, the other essentially local via a quantitative image analysis method developed and applied to High Resolution Transmission Electron Microscopy images. These two original approaches converge towards a clear description of 90^{circ} walls which are shown to be a 4 6 nm wide region where the crystallographic discontinuity is accommodated by irregular atomic displacements. The results given here demonstrate that the usual structural theoretical description of walls commonly accepted for energy calculations are far too simplistic. The two underlying methodologies which have been developed to carry out these approaches can possibly be applied to other ferroelectrics, but without any doubt to other systems where twins or coherent interfaces are expected. Une étude de la structure des murs de domaines ferroélectriques dans BaTiO3 est réalisée à travers deux approches complémentaires : une approche globale par une méthode fine d'analyse des diagrammes de poudre de diffraction des rayons X, et une autre très locale par une méthode quantitative d'analyse des images obtenues par microscopie électronique de haute résolution. Ces deux approches originales convergent vers une description claire des murs de domaines à 90^{circ} : c'est une région large de 4 6 nm où la discontinuité cristallographique est accommodée par des déplacements atomiques irréguliers. Ces résultats montrent que la description structurale théorique communément utilisée pour des calculs d'énergies est de loin trop simpliste. Les méthodologies développées, propres à chacune des analyses structurales utilisées, peuvent être appliquées à l'étude de tout autre matériau ferroélectrique, mais aussi à tout autre matériau cristallisé où des maclages ou interfaces cohérentes sont attendues.

  14. Switchable field-tuned control of magnetic domain wall pinning along Co microwires by 3D e-beam lithographed structures

    International Nuclear Information System (INIS)

    Blanco-Roldán, C.; Quirós, C.; Rodriguez-Rodriguez, G.; Vélez, M.; Martín, J.I.; Alameda, J.M.

    2016-01-01

    Three-dimensional magnetic circuits composed of Co microwires crossed by elevated Co bridges have been patterned on Si substrate by e-beam lithography and lift-off process. The lithographic procedure includes a double resist procedure that optimizes the shape of the bridge, so that 200 nm air gaps can be routinely achieved in between the wire and bridge elements. Microwire magnetization reversal processes have been analyzed by magneto-optical Kerr effect microscopy with different remanent bridge configurations. When the Co bridge is magnetized along the in-plane direction parallel to the wire axis, its stray field induces a marked pinning effect on domain wall propagation along the wire below it, even without being in contact. Changing the sign of the remanent state of the bridge, domain wall pinning can be selected to occur in either the ascending or descending branches of the wire hysteresis loop. Thus, these wire-bridge 3D circuits provide a simple system for tunable domain wall pinning controllable through the pre-recorded bridge remanent state. - Highlights: • Electron beam lithography is used to fabricate a tridimensional magnetic circuit. • Proposed circuit is made of a Co bridge overcrossing a non-contacted Co microwire. • Domain wall propagation can be controlled by previous magnetization of the system. • Domain wall pinning in the wire depends on the applied magnetic field sign.

  15. Switchable field-tuned control of magnetic domain wall pinning along Co microwires by 3D e-beam lithographed structures

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Roldán, C., E-mail: c.blanco@cinn.es [Departamento de Física, Universidad de Oviedo, Avenida Calvo Sotelo s/n, 33007 Oviedo (Spain); Centro de Investigación en Nanomateriales y Nanotecnología CINN (CSIC, Universidad de Oviedo), Avenida de la Vega 4-6, 33940 El Entrego (Spain); Quirós, C.; Rodriguez-Rodriguez, G.; Vélez, M.; Martín, J.I.; Alameda, J.M. [Departamento de Física, Universidad de Oviedo, Avenida Calvo Sotelo s/n, 33007 Oviedo (Spain); Centro de Investigación en Nanomateriales y Nanotecnología CINN (CSIC, Universidad de Oviedo), Avenida de la Vega 4-6, 33940 El Entrego (Spain)

    2016-02-15

    Three-dimensional magnetic circuits composed of Co microwires crossed by elevated Co bridges have been patterned on Si substrate by e-beam lithography and lift-off process. The lithographic procedure includes a double resist procedure that optimizes the shape of the bridge, so that 200 nm air gaps can be routinely achieved in between the wire and bridge elements. Microwire magnetization reversal processes have been analyzed by magneto-optical Kerr effect microscopy with different remanent bridge configurations. When the Co bridge is magnetized along the in-plane direction parallel to the wire axis, its stray field induces a marked pinning effect on domain wall propagation along the wire below it, even without being in contact. Changing the sign of the remanent state of the bridge, domain wall pinning can be selected to occur in either the ascending or descending branches of the wire hysteresis loop. Thus, these wire-bridge 3D circuits provide a simple system for tunable domain wall pinning controllable through the pre-recorded bridge remanent state. - Highlights: • Electron beam lithography is used to fabricate a tridimensional magnetic circuit. • Proposed circuit is made of a Co bridge overcrossing a non-contacted Co microwire. • Domain wall propagation can be controlled by previous magnetization of the system. • Domain wall pinning in the wire depends on the applied magnetic field sign.

  16. Interface-induced chiral domain walls, spin spirals and skyrmions revealed by spin-polarized scanning tunneling microscopy.

    Science.gov (United States)

    von Bergmann, Kirsten; Kubetzka, André; Pietzsch, Oswald; Wiesendanger, Roland

    2014-10-01

    The spin textures of ultra-thin magnetic layers exhibit surprising variety. The loss of inversion symmetry at the interface of the magnetic layer and substrate gives rise to the so-called Dzyaloshinskii-Moriya interaction which favors non-collinear spin arrangements with unique rotational sense. Here we review the application of spin-polarized scanning tunneling microscopy to such systems, which has led to the discovery of interface-induced chiral domain walls and spin spirals. Recently, different interface-driven skyrmion lattices have been found, and the writing as well as the deleting of individual skyrmions based on local spin-polarized current injection has been demonstrated. These interface-induced non-collinear magnetic states offer new exciting possibilities to study fundamental magnetic interactions and to tailor material properties for spintronic applications.

  17. Inhomogeneous nucleation and domain wall motion with Barkhausen avalanches in epitaxial PbZr0.4Ti0.6O3 thin films

    International Nuclear Information System (INIS)

    Yang, Sang Mo; Kim, Hun Ho; Kim, Tae Heon; Kim, Ik Joo; Yoon, Jong Gul

    2012-01-01

    We investigated the ferroelectric (FE) domain nucleation and domain wall motion in epitaxial PbZr 0.4 Ti 0.6 O 3 capacitors by using modified piezoresponse force microscopy with the domain-tracing method. From time-dependent FE domain evolution images, we observed that defect-mediated inhomogeneous nucleation occurred with a stochastic nature. In addition, we found that the number of nuclei N(t) was linearly proportional to log t, where t is the accumulated time of the applied pulse fields. The time-dependence of N(t) suggests a distribution of energy barriers for nucleation, which may determine the stochastic nature of domain nucleation. We also observed that the domain grew with consecutive Barkhausen avalanches and that the growth direction became anisotropic when the domain radius was larger than a critical radius of about 100 nm.

  18. The influence of thermal activation and the intrinsic temperature dependence of the spin torque effect in current-induced domain wall motion

    International Nuclear Information System (INIS)

    Dagras, P; Klaeui, M; Laufenberg, M; Bedau, D; Vila, L; Faini, G; Vaz, C A F; Bland, J A C; Ruediger, U

    2007-01-01

    An experimental study of domain wall motion in Ni 80 Fe 20 ring structures induced by current pulses as well as conventional magnetic fields is presented. Using constrictions we demonstrate that current-induced domain wall motion can be used to displace walls into parts of the structure where no pulsed currents are flowing. Measurements at variable temperatures between 2 and 300 K show that the fields necessary for wall motion decrease with increasing temperature, which can be explained by thermal activation. For the current-induced case we find, depending on the geometry and temperature range, that the current densities necessary for displacement can increase or decrease with rising temperature. This indicates that, in addition to thermal excitations, an intrinsic temperature dependence of the efficiency of the spin torque effect is present and leads to an increase in the critical current density with increasing temperature

  19. Spontaneous Z2 symmetry breaking in the orbifold daughter of N=1 super-Yang-Mills theory, fractional domain walls and vacuum structure

    International Nuclear Information System (INIS)

    Armoni, A.; Gorsky, A.; Shifman, M.

    2005-01-01

    We discuss the fate of the Z 2 symmetry and the vacuum structure in a SU(N)xSU(N) gauge theory with one bifundamental Dirac fermion. This theory can be obtained from SU(2N) supersymmetric Yang-Mills theory by virtue of Z 2 orbifolding. We analyze dynamics of domain walls and argue that the Z 2 symmetry is spontaneously broken. Since unbroken Z 2 is a necessary condition for nonperturbative planar equivalence we conclude that the orbifold daughter is nonperturbatively nonequivalent to its supersymmetric parent. En route, our investigation reveals the existence of fractional domain walls, similar to fractional D-branes of string theory on orbifolds. We conjecture on the fate of these domain walls in the true solution of the Z 2 -broken orbifold theory. We also comment on relation with nonsupersymmetric string theories and closed-string tachyon condensation

  20. Collective coordinate models of domain wall motion in perpendicularly magnetized systems under the spin hall effect and longitudinal fields

    Energy Technology Data Exchange (ETDEWEB)

    Nasseri, S. Ali, E-mail: ali.nasseri@isi.it [ISI Foundation - Via Alassio 11/c –10126 Torino (Italy); Politecnico di Torino - Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Moretti, Simone; Martinez, Eduardo [University of Salamanca - Cardenal Plá y Deniel, 22, 37008 Salamanca (Spain); Serpico, Claudio [ISI Foundation - Via Alassio 11/c –10126 Torino (Italy); University of Naples Federico II - Via Claudio 21, 80125 Napoli (Italy); Durin, Gianfranco [ISI Foundation - Via Alassio 11/c –10126 Torino (Italy); Istituto Nazionale di Ricerca Metrologica (INRIM) - Strada delle Cacce 91, 10135 Torino (Italy)

    2017-03-15

    Recent studies on heterostructures of ultrathin ferromagnets sandwiched between a heavy metal layer and an oxide have highlighted the importance of spin-orbit coupling (SOC) and broken inversion symmetry in domain wall (DW) motion. Specifically, chiral DWs are stabilized in these systems due to the Dzyaloshinskii-Moriya interaction (DMI). SOC can also lead to enhanced current induced DW motion, with the Spin Hall effect (SHE) suggested as the dominant mechanism for this observation. The efficiency of SHE driven DW motion depends on the internal magnetic structure of the DW, which could be controlled using externally applied longitudinal in-plane fields. In this work, micromagnetic simulations and collective coordinate models are used to study current-driven DW motion under longitudinal in-plane fields in perpendicularly magnetized samples with strong DMI. Several extended collective coordinate models are developed to reproduce the micromagnetic results. While these extended models show improvements over traditional models of this kind, there are still discrepancies between them and micromagnetic simulations which require further work. - Highlights: • Moving DWs in PMA material maintain their structure under longitudinal in-plane fields. • As a result of longitudinal fields, magnetization in the domains becomes canted. • A critical longitudinal field was identified and correlated with the DMI strength. • A canted collective coordinate model was developed for DW motion under in-plane fields.

  1. Wall Painting Investigation by Means of Non-invasive Terahertz Time-Domain Imaging (THz-TDI): Inspection of Subsurface Structures Buried in Historical Plasters

    Science.gov (United States)

    Dandolo, Corinna Ludovica Koch; Jepsen, Peter Uhd

    2016-02-01

    Characterization of subsurface features of wall paintings is important in conservation and technical art history as well as in building archaeology and architecture fields. In this study, an area of the apsidal wall painting of Nebbelunde Church (Rødby, Denmark) has been investigated by means of terahertz time-domain imaging (THz-TDI). Subsurface structures have been detected at different depths inside the lime-based plaster of the wall painting until approximately 1 cm from the surface. The surface morphology of the buried structures has been 3D imaged in detail, providing a substantial contribution in their characterization.

  2. MFM observations of domain wall creep and pinning effects in amorphous Co{sub x}Si{sub 1-x} films with diluted arrays of antidots

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Rodriguez, G [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Perez-Junquera, A [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Velez, M [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Anguita, J V [Instituto de Microelectronica de Madrid, CNM-CSIC, Isaac Newton 8, PTM, Tres Cantos, 28760 Madrid (Spain); Martin, J I [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Rubio, H [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Alameda, J M [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain)

    2007-05-21

    Magnetic force microscopy (MFM) has been used to analyse the behaviour of domain walls in uniaxial amorphous Co{sub x}Si{sub 1-x} films patterned with diluted arrays of antidots by electron beam lithography. The walls are found to be pinned by the antidot array when the antidot density is high enough along the easy axis. The expansion of reversed nuclei under the influence of the tip stray field has been observed in several consecutive MFM images of the same area, showing how the competition between line tension effects and pinning by the patterned holes governs the creep motion of the 180{sup 0} walls across the array of antidots.

  3. MFM observations of domain wall creep and pinning effects in amorphous CoxSi1-x films with diluted arrays of antidots

    International Nuclear Information System (INIS)

    Rodriguez-Rodriguez, G; Perez-Junquera, A; Velez, M; Anguita, J V; Martin, J I; Rubio, H; Alameda, J M

    2007-01-01

    Magnetic force microscopy (MFM) has been used to analyse the behaviour of domain walls in uniaxial amorphous Co x Si 1-x films patterned with diluted arrays of antidots by electron beam lithography. The walls are found to be pinned by the antidot array when the antidot density is high enough along the easy axis. The expansion of reversed nuclei under the influence of the tip stray field has been observed in several consecutive MFM images of the same area, showing how the competition between line tension effects and pinning by the patterned holes governs the creep motion of the 180 0 walls across the array of antidots

  4. Separating spin torque and heating effects in current-induced domain wall motion probed by high-resolution transmission electron microscopy

    DEFF Research Database (Denmark)

    Junginger, F.; Klaeui, M.; Backes, D.

    2007-01-01

    Observations of domain wall motion and transformations due to injected current pulses in permalloy zigzag structures using off-axis electron holography and Lorentz microscopy are reported. Heating on membranes leads to thermally activated random behavior at low current densities and by backcoatin...

  5. Wall Painting Investigation by Means of Non-invasive Terahertz Time-Domain Imaging (THz-TDI): Inspection of Subsurface Structures Buried in Historical Plasters

    DEFF Research Database (Denmark)

    Dandolo, Corinna Ludovica Koch; Jepsen, Peter Uhd

    2016-01-01

    of terahertz time-domain imaging (THz-TDI). Subsurface structures have been detected at different depths inside the lime-based plaster of the wall painting until approximately 1 cm from the surface. The surface morphology of the buried structures has been 3D imaged in detail, providing a substantial...

  6. The Stripe State in Cupratesa

    Directory of Open Access Journals (Sweden)

    Lee T.-K.

    2012-03-01

    Full Text Available Since the discovery of high temperature superconductors (HTS two decades ago, many anomalous properties have been reported. One of the most interesting properties is the possible existence of the stripe state consisting of one dimensional charge-density modulation coupled with some kind of spin ordering. X-ray and neutron scattering experiments and recently high resolution scanning tunneling microscopy have reported direct evidences of such a structure. In particular it has found in the La-Sr-Cu-O (LSCO family the existence of the half-doped stripe with average of half a hole in one charge modulation period below and about 1/8 hole density. These results have fueled the idea about the presence of these charge or spin density wave states competing with the superconducting phase in underdoped HTS. They may even contribute to the pairing mechanism. In this talk, we will demonstrate that the presence of these stripes is actually a natural consequence of the strongly interacting t-J model by using a variational approach which provides a good enough accuracy to address the subtle result. Furthermore we show that half-doped stripes could be stabilized in hole-doped systems if we assume a simple electron-phonon interaction to renormalize the electron mass. However we have not found any evidence to support half-doped stripes in electron-doped systems.

  7. Birth, growth and death of an antivortex during the propagation of a transverse domain wall in magnetic nanostrips

    Science.gov (United States)

    Yuan, H. Y.; Wang, X. R.

    2014-11-01

    Antivortex birth, growth and death accompanying the propagation of a transverse domain wall (DW) in magnetic nanostrips are observed and analyzed. Antivortex formation is an intrinsic process of a strawberry-like transverse DW originated from magnetostatic interaction. Under an external magnetic field, the wider width region of a DW tends to move faster than the narrower one. This speed mismatch tilts and elongates DW center line. As a result, an antivortex with a well-defined polarity is periodically born near the tail of the DW center line. The antivortex either moves along the center line and dies on the other side of the nanostrip, or grows to its maximum size, detaches itself from the DW, and vanishes eventually. The former route reverses the polarity of DW while the later keeps the DW polarity unchanged. The evolution of the DW structures is analyzed using winding numbers assigned to each topological defects. The phase diagram in the field-width plane is obtained and the damping constant's influence on the phase diagram is discussed.

  8. Domain-wall motion at an ultrahigh speed driven by spin–orbit torque in synthetic antiferromagnets

    Science.gov (United States)

    Yu, Ziyang; Zhang, Yue; Zhang, Zhenhua; Cheng, Ming; Lu, Zhihong; Yang, Xiaofei; Shi, Jing; Xiong, Rui

    2018-04-01

    In this article, we present our numerical investigation about the spin–orbit-torque induced domain-wall (DW) motion in a synthetic antiferromagnetic multilayer nanotrack. This nanotrack was composed by two ferromagnetic (FM) layers with a RKKY inter-layer antiferromagnetic (AFM) exchange coupling. The velocity of DW was well manipulated by varying parameters including inter-layer exchange constant, the Dzyaloshinskii–Moriya interaction (DMI) strength, the current density and the magnetic anisotropy. The DW velocity was found to be strictly related to the orientation of the moments in the two FM layers. When the interlayer exchange constant or the DMI constant were larger than a critical value, there was a large angle between the moments in one FM layer and that in the other one under the current, and the DW was driven to move at an ultrahigh speed (around 10 000 m s‑1). However, when the DMI or the AFM exchange coupling was weaker than the critical value, the moments in one FM layer were parallel to that in the other one under the current, and the velocity was significantly reduced.

  9. Magnetic domain-wall creep driven by field and current in Ta/CoFeB/MgO

    Science.gov (United States)

    DuttaGupta, S.; Fukami, S.; Kuerbanjiang, B.; Sato, H.; Matsukura, F.; Lazarov, V. K.; Ohno, H.

    2017-05-01

    Creep motion of magnetic domain wall (DW), thermally activated DW dynamics under subthreshold driving forces, is a paradigm to understand the interaction between driven interfaces and applied external forces. Previous investigation has shown that DW in a metallic system interacts differently with current and magnetic field, manifesting itself as different universality classes for the creep motion. In this article, we first review the experimental determination of the universality classes for current- and field-driven DW creeps in a Ta/CoFeB/MgO wire, and then elucidate the underlying factors governing the obtained results. We show that the nature of torque arising from current in association with DW configuration determines universality class for the current-induced creep in this system. We also discuss the correlation between the field-induced DW creep characteristics and structure observed by a transmission electron microscope. The observed results are expected to provide a deeper understanding for physics of DW motion in various magnetic materials.

  10. Magnetic domain-wall creep driven by field and current in Ta/CoFeB/MgO

    Directory of Open Access Journals (Sweden)

    S. DuttaGupta

    2017-05-01

    Full Text Available Creep motion of magnetic domain wall (DW, thermally activated DW dynamics under subthreshold driving forces, is a paradigm to understand the interaction between driven interfaces and applied external forces. Previous investigation has shown that DW in a metallic system interacts differently with current and magnetic field, manifesting itself as different universality classes for the creep motion. In this article, we first review the experimental determination of the universality classes for current- and field-driven DW creeps in a Ta/CoFeB/MgO wire, and then elucidate the underlying factors governing the obtained results. We show that the nature of torque arising from current in association with DW configuration determines universality class for the current-induced creep in this system. We also discuss the correlation between the field-induced DW creep characteristics and structure observed by a transmission electron microscope. The observed results are expected to provide a deeper understanding for physics of DW motion in various magnetic materials.

  11. Lateral flow assay-based bacterial detection using engineered cell wall binding domains of a phage endolysin.

    Science.gov (United States)

    Kong, Minsuk; Shin, Joong Ho; Heu, Sunggi; Park, Je-Kyun; Ryu, Sangryeol

    2017-10-15

    The development of a cost-effective and efficient bacterial detection assay is essential for diagnostic fields, particularly in resource-poor settings. Although antibodies have been widely used for bacterial capture, the production of soluble antibodies is still expensive and time-consuming. Here, we developed a nitrocellulose-based lateral flow assay using cell wall binding domains (CBDs) from phage as a recognition element and colloidal gold nanoparticles as a colorimetric signal for the detection of a model pathogenic bacterium, Bacillus cereus (B. cereus). To improve conjugation efficiency and detection sensitivity, cysteine-glutathione-S-transferase-tagged CBDs and maltose-binding protein-tagged CBDs were produced in Escherichia coli (E. coli) and incorporated in our assays. The sensitivity of the strip to detect B. cereus was 1×10 4 CFU/mL and the overall assay time was 20min. The assay showed superior results compared to the antibody-based approach, and did not show any significant cross-reactivity. This proof of concept study indicates that the lateral flow assay using engineered CBDs hold considerable promise as simple, rapid, and cost-effective biosensors for whole cell detection. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Competition between domain walls and the reverse magnetization in the magnetic relaxation of a Pt/Co/Ir/Co/Pt spin switcher

    Science.gov (United States)

    Morgunov, R. B.; L'vova, G. L.; Hamadeh, A.; Mangin, S.

    2018-01-01

    A multilayer Pt/Co/Ir/Co/Pt/GaAs heterostructures demonstrates a long term (to several hours) magnetic relaxation between two stable states of the magnetization of the system. The magnetization reversal of the heterostructure layers occurs both due to the formation of nuclei of the reverse magnetization domains and as a result of their further growth by means of motion of domain walls. The competition between two these processes provides a nonexponential character of the magnetic relaxation. At 300 K, the contributions of these processes to the relaxation are commensurable, while, at temperatures lower than 200 K, the contribution of the nucleation is suppressed and the magnetic relaxation occurs as a result of motion of the domain walls.

  13. Improving striping operations through system optimization.

    Science.gov (United States)

    2015-09-01

    Striping operations generate a significant workload for Missouri Department of Transportation (MoDOT) maintenance : operations. The requirement for each striping crew to replenish its stock of paint and other consumable items from a bulk storage : fa...

  14. Domain Walls Conductivity in Hybrid Organometallic Perovskites and Their Essential Role in CH3NH3PbI3 Solar Cell High Performance

    Science.gov (United States)

    Rashkeev, Sergey N.; El-Mellouhi, Fedwa; Kais, Sabre; Alharbi, Fahhad H.

    2015-01-01

    The past several years has witnessed a surge of interest in organometallic trihalide perovskites, which are at the heart of the new generation of solid-state solar cells. Here, we calculated the static conductivity of charged domain walls in n- and p- doped organometallic uniaxial ferroelectric semiconductor perovskite CH3NH3PbI3 using the Landau-Ginzburg-Devonshire (LGD) theory. We find that due to the charge carrier accumulation, the static conductivity may drastically increase at the domain wall by 3 – 4 orders of magnitude in comparison with conductivity through the bulk of the material. Also, a two-dimensional degenerated gas of highly mobile charge carriers could be formed at the wall. The high values of conductivity at domain walls and interfaces explain high efficiency in organometallic solution-processed perovskite films which contains lots of different point and extended defects. These results could suggest new routes to enhance the performance of this promising class of novel photovoltaic materials. PMID:26088321

  15. Charge stripes and spin correlations in copper-oxide superconductors

    OpenAIRE

    Tranquada, J. M.

    1997-01-01

    Recent neutron diffraction studies have yielded evidence that, in a particular cuprate family, holes doped into the CuO(2) planes segregate into stripes that separate antiferromagnetic domains. Here it is shown that such a picture provides a quantitatively consistent interpretation of the spin fluctuations measured by neutron scattering in La(1.85)Sr(0.15)CuO(4) and YBa(2)Cu(3)O(6+x).

  16. Domain walls of BaTiO.sub.3./sub. and PbTiO.sub.3./sub. within Ginzburg-Landau-Devonshire model

    Czech Academy of Sciences Publication Activity Database

    Hlinka, Jiří

    2008-01-01

    Roč. 375, č. 1 (2008), 132-137 ISSN 0015-0193 R&D Projects: GA ČR GA202/06/0411 Institutional research plan: CEZ:AV0Z10100520 Keywords : domain walls * Landau- Ginsburg theory * ferroelectricity * BaTiO 3 * PbTiO 3 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.562, year: 2008

  17. Phenomenological model of a 90.sup.o./sup. domain wall in BaTiO.sub.3./sub.-type ferroelectrics

    Czech Academy of Sciences Publication Activity Database

    Hlinka, Jiří; Márton, Pavel

    2006-01-01

    Roč. 74, č. 10 (2006), 104104/1-104104/12 ISSN 1098-0121 R&D Projects: GA ČR(CZ) GD202/05/H003; GA ČR GA202/06/0411 Institutional research plan: CEZ:AV0Z10100520 Keywords : BaTiO3 3 * ferroelectrics * domain wall * Ginzburg-Landau model Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.107, year: 2006

  18. Transcript Profiling Identifies NAC-Domain Genes Involved in Regulating Wall Ingrowth Deposition in Phloem Parenchyma Transfer Cells of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Yuzhou Wu

    2018-03-01

    Full Text Available Transfer cells (TCs play important roles in facilitating enhanced rates of nutrient transport at key apoplasmic/symplasmic junctions along the nutrient acquisition and transport pathways in plants. TCs achieve this capacity by developing elaborate wall ingrowth networks which serve to increase plasma membrane surface area thus increasing the cell's surface area-to-volume ratio to achieve increased flux of nutrients across the plasma membrane. Phloem parenchyma (PP cells of Arabidopsis leaf veins trans-differentiate to become PP TCs which likely function in a two-step phloem loading mechanism by facilitating unloading of photoassimilates into the apoplasm for subsequent energy-dependent uptake into the sieve element/companion cell (SE/CC complex. We are using PP TCs in Arabidopsis as a genetic model to identify transcription factors involved in coordinating deposition of the wall ingrowth network. Confocal imaging of pseudo-Schiff propidium iodide-stained tissue revealed different profiles of temporal development of wall ingrowth deposition across maturing cotyledons and juvenile leaves, and a basipetal gradient of deposition across mature adult leaves. RNA-Seq analysis was undertaken to identify differentially expressed genes common to these three different profiles of wall ingrowth deposition. This analysis identified 68 transcription factors up-regulated two-fold or more in at least two of the three experimental comparisons, with six of these transcription factors belonging to Clade III of the NAC-domain family. Phenotypic analysis of these NAC genes using insertional mutants revealed significant reductions in levels of wall ingrowth deposition, particularly in a double mutant of NAC056 and NAC018, as well as compromised sucrose-dependent root growth, indicating impaired capacity for phloem loading. Collectively, these results support the proposition that Clade III members of the NAC-domain family in Arabidopsis play important roles in

  19. Transcript Profiling Identifies NAC-Domain Genes Involved in Regulating Wall Ingrowth Deposition in Phloem Parenchyma Transfer Cells ofArabidopsis thaliana.

    Science.gov (United States)

    Wu, Yuzhou; Hou, Jiexi; Yu, Fen; Nguyen, Suong T T; McCurdy, David W

    2018-01-01

    Transfer cells (TCs) play important roles in facilitating enhanced rates of nutrient transport at key apoplasmic/symplasmic junctions along the nutrient acquisition and transport pathways in plants. TCs achieve this capacity by developing elaborate wall ingrowth networks which serve to increase plasma membrane surface area thus increasing the cell's surface area-to-volume ratio to achieve increased flux of nutrients across the plasma membrane. Phloem parenchyma (PP) cells of Arabidopsis leaf veins trans -differentiate to become PP TCs which likely function in a two-step phloem loading mechanism by facilitating unloading of photoassimilates into the apoplasm for subsequent energy-dependent uptake into the sieve element/companion cell (SE/CC) complex. We are using PP TCs in Arabidopsis as a genetic model to identify transcription factors involved in coordinating deposition of the wall ingrowth network. Confocal imaging of pseudo-Schiff propidium iodide-stained tissue revealed different profiles of temporal development of wall ingrowth deposition across maturing cotyledons and juvenile leaves, and a basipetal gradient of deposition across mature adult leaves. RNA-Seq analysis was undertaken to identify differentially expressed genes common to these three different profiles of wall ingrowth deposition. This analysis identified 68 transcription factors up-regulated two-fold or more in at least two of the three experimental comparisons, with six of these transcription factors belonging to Clade III of the NAC-domain family. Phenotypic analysis of these NAC genes using insertional mutants revealed significant reductions in levels of wall ingrowth deposition, particularly in a double mutant of NAC056 and NAC018 , as well as compromised sucrose-dependent root growth, indicating impaired capacity for phloem loading. Collectively, these results support the proposition that Clade III members of the NAC-domain family in Arabidopsis play important roles in regulating wall

  20. Current induced domain wall motion and tilting in Pt/Co/Ta structures with perpendicular magnetic anisotropy in the presence of the Dyzaloshinskii–Moriya interaction

    Science.gov (United States)

    Yun, Jijun; Li, Dong; Cui, Baoshan; Guo, Xiaobin; Wu, Kai; Zhang, Xu; Wang, Yupei; Mao, Jian; Zuo, Yalu; Xi, Li

    2018-04-01

    Current induced domain wall motion (CIDWM) was studied in Pt/Co/Ta structures with perpendicular magnetic anisotropy and the Dyzaloshinskii–Moriya interaction (DMI) by the spin-orbit torque (SOT). We measured the strength of DMI and SOT efficiency in Pt/Co/Ta with the variation of the thickness of Ta using a current induced hysteresis loop shift method. The results indicate that the DMI stabilizes a chiral Néel-type domain wall (DW), and the DW motion can be driven by the enhanced large SOT generated from Pt and Ta with opposite signs of spin Hall angle in Pt/Co/Ta stacks. The CIDWM velocity, which is 104 times larger than the field driven DW velocity, obeys a creep law, and reaches around tens of meters per second with current density of ~106 A cm‑2. We also found that the Joule heating accompanied with current also accelerates the DW motion. Meanwhile, a domain wall tilting was observed, which increases with current density increasing. These results can be explained by the spin Hall effect generated from both heavy metals Pt and Ta, inherent DMI, and the current accompanying Joule heating effect. Our results could provide some new designing prospects to move multiple DWs by SOT for achieving racetrack memories.

  1. Overlap valence on 2+1 flavor domain wall fermion configurations with deflation and low-mode substitution

    International Nuclear Information System (INIS)

    Li, A.; Alexandru, A.; Lee, F. X.; Chen, Y.; Doi, T.; Dong, S. J.; Draper, T.; Gong, M.; Horvath, I.; Liu, K. F.; Hasenfratz, A.; Mathur, N.; Streuer, T.; Zhang, J. B.

    2010-01-01

    The overlap fermion propagator is calculated on 2+1 flavor domain-wall fermion gauge configurations on 16 3 x32, 24 3 x64 and 32 3 x64 lattices. With hyper-cubic (HYP) smearing and low eigenmode deflation, it is shown that the inversion of the overlap operator can be expedited by ∼20 times for the 16 3 x32 lattice and ∼80 times for the 32 3 x64 lattice. The overhead cost for calculating eigenmodes ranges from 4.5 to 7.9 propagators for the above lattices. Through the study of hyperfine splitting, we found that the O(m 2 a 2 ) error is small and these dynamical fermion lattices can adequately accommodate quark mass up to the charm quark. A preliminary calculation of the low-energy constant Δ mix which characterizes the discretization error of the pion made up of a pair of sea and valence quarks in this mixed-action approach is carried out via the scalar correlator with periodic and antiperiodic boundary conditions. It is found to be small which shifts a 300 MeV pion mass by ∼10 to 19 MeV on these sets of lattices. We have studied the signal-to-noise issue of the noise source for the meson and baryon. We introduce a new algorithm with Z 3 grid source and low eigenmode substitution to study the many-to-all meson and baryon correlators. It is found to be efficient in reducing errors for the correlators of both mesons and baryons. With 64-point Z 3 grid source and low-mode substitution, it can reduce the statistical errors of the light quark (m π ∼200-300 MeV) meson and nucleon correlators by a factor of ∼3-4 as compared to the point source. The Z 3 grid source itself can reduce the errors of the charmonium correlators by a factor of ∼3.

  2. Bulk temperature measurement in thermally striped pipe flows

    International Nuclear Information System (INIS)

    Lemure, N.; Olvera, J.R.; Ruggles, A.E.

    1995-12-01

    The hot leg flows in some Pressurized Water Reactor (PWR) designs have a temperature distribution across the pipe cross-section. This condition is often referred to as a thermally striped flow. Here, the bulk temperature measurement of pipe flows with thermal striping is explored. An experiment is conducted to examine the feasibility of using temperature measurements on the external surface of the pipe to estimate the bulk temperature of the flow. Simple mixing models are used to characterize the development of the temperature profile in the flow. Simple averaging techniques and Backward Propagating Neural Net are used to predict bulk temperature from the external temperature measurements. Accurate bulk temperatures can be predicted. However, some temperature distributions in the flow effectively mask the bulk temperature from the wall and cause significant error in the bulk temperature predicted using this technique

  3. Dynamical implications of sample shape for avalanches in 2-dimensional random-field Ising model with saw-tooth domain wall

    Science.gov (United States)

    Tadić, Bosiljka

    2018-03-01

    We study dynamics of a built-in domain wall (DW) in 2-dimensional disordered ferromagnets with different sample shapes using random-field Ising model on a square lattice rotated by 45 degrees. The saw-tooth DW of the length Lx is created along one side and swept through the sample by slow ramping of the external field until the complete magnetisation reversal and the wall annihilation at the open top boundary at a distance Ly. By fixing the number of spins N =Lx ×Ly = 106 and the random-field distribution at a value above the critical disorder, we vary the ratio of the DW length to the annihilation distance in the range Lx /Ly ∈ [ 1 / 16 , 16 ] . The periodic boundary conditions are applied in the y-direction so that these ratios comprise different samples, i.e., surfaces of cylinders with the changing perimeter Lx and height Ly. We analyse the avalanches of the DW slips between following field updates, and the multifractal structure of the magnetisation fluctuation time series. Our main findings are that the domain-wall lengths materialised in different sample shapes have an impact on the dynamics at all scales. Moreover, the domain-wall motion at the beginning of the hysteresis loop (HLB) probes the disorder effects resulting in the fluctuations that are significantly different from the large avalanches in the central part of the loop (HLC), where the strong fields dominate. Specifically, the fluctuations in HLB exhibit a wide multi-fractal spectrum, which shifts towards higher values of the exponents when the DW length is reduced. The distributions of the avalanches in this segments of the loops obey power-law decay and the exponential cutoffs with the exponents firmly in the mean-field universality class for long DW. In contrast, the avalanches in the HLC obey Tsallis density distribution with the power-law tails which indicate the new categories of the scale invariant behaviour for different ratios Lx /Ly. The large fluctuations in the HLC, on the other

  4. Unfolding of Vortices into Topological Stripes in a Multiferroic Material

    NARCIS (Netherlands)

    Mostovoy, Maxim; Wang, X.; Han, M. G.; Horibe, Y.; Aoki, T.; Zhu, Y.; Cheong, S.-W.

    2014-01-01

    Multiferroic hexagonal RMnO3 (R=rare earths) crystals exhibit dense networks of vortex lines at which six domain walls merge. While the domain walls can be readily moved with an applied electric field, the vortex cores so far have been impossible to control. Our experiments demonstrate that shear

  5. One repeat of the cell wall binding domain is sufficient for anchoring the Lactobacillus acidophilus surface layer protein

    NARCIS (Netherlands)

    Smit, E.; Pouwels, P.H.

    2002-01-01

    The N-terminal repeat (SAC1) of the S-protein of Lactobacillus acidophilus bound efficiently and specifically to cell wall fragments (CWFs) when fused to green fluorescent protein, whereas the C-terminal repeat (SAC2) did not. Treatment of CWFs with hydrofluoric acid, but not phenol, prevented

  6. Superstructural chirality of a periodic system of domains of opposite chirality and π-walls in B.sub.2./sub. phase composed of bent-shaped molecules

    Czech Academy of Sciences Publication Activity Database

    Lejček, Lubor

    2010-01-01

    Roč. 83, 10-11 (2010), s. 1001-1013 ISSN 0141-1594 R&D Projects: GA AV ČR IAA100100911; GA AV ČR(CZ) GA202/09/0047; GA MŠk(CZ) OC10006 Institutional research plan: CEZ:AV0Z10100520 Keywords : B 2 phase * bent-shaped molecules * domains of opposite chirality * π-walls * superstructural chirality Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.006, year: 2010

  7. Invasion of the striped mollusks

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Introduced to this country only five years ago, the prolific zebra mussel has infested the Great Lakes and has already begun to move into fresh waters beyond the region. Dense populations in utility water systems have caused serious problems, reducing plant efficiency and blocking lines used for cooling and fire fighting. Experts say the striped mollusk has the potential to become the industry's worst biological problem, possibly affecting 70% of US power plants. While it appears that the invader is here to stay, EPRI and others continue to develop and refine techniques to control mussel growth

  8. Computer simulations of sequency-dependent dielectric response of 90-degree domain walls in tetragonal barium titanate

    Czech Academy of Sciences Publication Activity Database

    Márton, Pavel; Hlinka, Jiří

    2008-01-01

    Roč. 373, č. 1 (2008), s. 139-144 ISSN 0015-0193 R&D Projects: GA ČR GA202/06/0411 Institutional research plan: CEZ:AV0Z10100520 Keywords : ferroelectric and ferroelastic domains * BaTiO 3 * Ginzburg-Landau theory * mobility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.562, year: 2008

  9. Response to "Critical Assessment of the Evidence for Striped Nanoparticles".

    Directory of Open Access Journals (Sweden)

    Quy Khac Ong

    Full Text Available Stirling et al., (10.1371/journal.pone.0108482 presented an analysis on some of our publications on the formation of stripe-like domains on mixed-ligand coated gold nanoparticles. The authors shed doubts on some of our results however no valid argument is provided against what we have shown since our first publication: scanning tunneling microscopy (STM images of striped nanoparticles show stripe-like domains that are independent of imaging parameters and in particular of imaging speed. We have consistently ruled out the presence of artifacts by comparing sets of images acquired at different tip speeds, finding invariance of the stipe-like domains. Stirling and co-workers incorrectly analyzed this key control, using a different microscope and imaging conditions that do not compare to ours. We show here data proving that our approach is rigorous. Furthermore, we never solely relied on image analysis to draw our conclusions; we have always used the chemical nature of the particles to assess the veracity of our images. Stirling et al. do not provide any justification for the spacing of the features that we find on nanoparticles: ~1 nm for mixed ligand particles and ~ 0.5 nm for homoligand particles. Hence our two central arguments remain unmodified: independence from imaging parameters and dependence on ligand shell chemical composition. The paper report observations on our STM images; none is a sufficient condition to prove that our images are artifacts. We thoroughly addressed issues related to STM artifacts throughout our microscopy work. Stirling et al. provide guidelines for what they consider good STM images of nanoparticles, such images are indeed present in our literature. They conclude that the evidences we provided to date are insufficient, this is a departure from one of the authors' previous article which concluded that our images were composed of artifacts. Given that four independent laboratories have reproduced our measurements and

  10. Invasion of the striped mollusks

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    Introduced to this country only five years ago, the prolific zebra mussel has infested the Great Lakes and has already begun to move into fresh waters beyond the region. Dense populations in utility water systems have caused serious problems, reducing plant efficiency and blocking lines used for cooling and fire fighting. Experts say the striped mollusk has the potential to become the industry's worst biological problem, possibly affecting 70% of US power plants. While it appears that the invader is here to stay, EPRI and others continue to develop and refine techniques to control mussel growth. This article describes how the mollusk got here, reviews the problems it can cause and what is being done to mitigate the problems and control the growth and spread of the mollusk.

  11. The myosin motor domain-containing chitin synthase PdChsVII is required for development, cell wall integrity and virulence in the citrus postharvest pathogen Penicillium digitatum.

    Science.gov (United States)

    Gandía, Mónica; Harries, Eleonora; Marcos, Jose F

    2014-06-01

    Chitin is an essential component of the fungal cell wall and a potential target in the development of new antifungal compounds, due to its presence in fungi and not in plants or vertebrates. Chitin synthase genes (chs) constitute a complex family in filamentous fungi and are involved in fungal development, morphogenesis, pathogenesis and virulence. In this study, additional chs genes in the citrus postharvest pathogen Penicillium digitatum have been identified. Comparative analyses included each PdChs in each one of the classes I to VII previously established, and support the grouping of these into three divisions. Disruption of the gene coding PdChsVII, which contains a short version of a myosin motor domain, has been achieved by using Agrobacterium tumefaciens-mediated transformation and revealed its role in the life cycle of the fungus. Disruption strains were viable but showed reduced growth and conidia production. Moreover, Pdchs mutants developed morphological defects as balloon-like enlarged cells and increased chitin content, indicative of an altered cell wall structure. Gene disruption also increased susceptibility to antifungal compounds such as calcofluor white (CFW), sodium dodecyl sulfate (SDS), hydroxide peroxide (H2O2) and commercial fungicides, but significantly no change was observed in the sensitivity to antifungal peptides. The PdchsVII mutants were able to infect citrus fruit and produced tissue maceration, although had reduced virulence and most importantly were greatly impaired in the production of visible mycelium and conidia on the fruit. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Identification of Two Binding Domains, One for Peptidoglycan and Another for a Secondary Cell Wall Polymer, on the N-Terminal Part of the S-Layer Protein SbsB from Bacillus stearothermophilus PV72/p2

    Science.gov (United States)

    Sára, Margit; Egelseer, Eva M.; Dekitsch, Christine; Sleytr, Uwe B.

    1998-01-01

    First studies on the structure-function relationship of the S-layer protein from B. stearothermophilus PV72/p2 revealed the coexistence of two binding domains on its N-terminal part, one for peptidoglycan and another for a secondary cell wall polymer (SCWP). The peptidoglycan binding domain is located between amino acids 1 to 138 of the mature S-layer protein comprising a typical S-layer homologous domain. The SCWP binding domain lies between amino acids 240 to 331 and possesses a high serine plus glycine content. PMID:9852032

  13. Stock characteristics of Hudson River striped bass

    International Nuclear Information System (INIS)

    Hoff, T.B.; McLaren, J.B.; Cooper, J.C.

    1988-01-01

    Striped bass, because of their tremendous popularity both commercially and recreationally, were a principal focus of the Hudson River power plant case. Between 1976 and 1979, over 23,000 age-II and older striped bass were studied as one facet of an extensive research program on the spring population in the Hudson River. Samples were collected from the overwintering as well as the spawning portion of the striped bass population, and included immature as well as mature fish. At least 12 age-groups contributed to spawning each year. Of these 12, age-groups III, IV, and V usually were most abundant, but the percentage of the population represented by any single age-group varied as the result of fluctuations in year-class strength. Males first became sexually mature at age II and females at age IV. Fast-growing individuals within a year class tended to mature earlier. Fecundity increased with the size of fish, reaching an observed maximum of about 3 million eggs per female. Although significant annual variations in maturity and growth were detected for Hudson River striped bass, there was no evidence of a consistent change in either variable that might be associated with increasing power plant operations and a reduction in striped bass abundance. Age at maturity and age structure are the two life history components that differ the most between the Hudson River population and other striped bass populations. 36 refs., 7 tabs

  14. A Thermophilic Phage Endolysin Fusion to a Clostridium perfringens-Specific Cell Wall Binding Domain Creates an Anti-Clostridium Antimicrobial with Improved Thermostability

    Directory of Open Access Journals (Sweden)

    Steven M. Swift

    2015-06-01

    Full Text Available Clostridium perfringens is the third leading cause of human foodborne bacterial disease and is the presumptive etiologic agent of necrotic enteritis among chickens. Treatment of poultry with antibiotics is becoming less acceptable. Endolysin enzymes are potential replacements for antibiotics. Many enzymes are added to animal feed during production and are subjected to high-heat stress during feed processing. To produce a thermostabile endolysin for treating poultry, an E. coli codon-optimized gene was synthesized that fused the N-acetylmuramoyl-L-alanine amidase domain from the endolysin of the thermophilic bacteriophage ɸGVE2 to the cell-wall binding domain (CWB from the endolysin of the C. perfringens-specific bacteriophage ɸCP26F. The resulting protein, PlyGVE2CpCWB, lysed C. perfringens in liquid and solid cultures. PlyGVE2CpCWB was most active at pH 8, had peak activity at 10 mM NaCl, 40% activity at 150 mM NaCl and was still 16% active at 600 mM NaCl. The protein was able to withstand temperatures up to 50° C and still lyse C. perfringens. Herein, we report the construction and characterization of a thermostable chimeric endolysin that could potentially be utilized as a feed additive to control the bacterium during poultry production.

  15. A Thermophilic Phage Endolysin Fusion to a Clostridium perfringens-Specific Cell Wall Binding Domain Creates an Anti-Clostridium Antimicrobial with Improved Thermostability.

    Science.gov (United States)

    Swift, Steven M; Seal, Bruce S; Garrish, Johnna K; Oakley, Brian B; Hiett, Kelli; Yeh, Hung-Yueh; Woolsey, Rebekah; Schegg, Kathleen M; Line, John Eric; Donovan, David M

    2015-06-12

    Clostridium perfringens is the third leading cause of human foodborne bacterial disease and is the presumptive etiologic agent of necrotic enteritis among chickens. Treatment of poultry with antibiotics is becoming less acceptable. Endolysin enzymes are potential replacements for antibiotics. Many enzymes are added to animal feed during production and are subjected to high-heat stress during feed processing. To produce a thermostabile endolysin for treating poultry, an E. coli codon-optimized gene was synthesized that fused the N-acetylmuramoyl-L-alanine amidase domain from the endolysin of the thermophilic bacteriophage ɸGVE2 to the cell-wall binding domain (CWB) from the endolysin of the C. perfringens-specific bacteriophage ɸCP26F. The resulting protein, PlyGVE2CpCWB, lysed C. perfringens in liquid and solid cultures. PlyGVE2CpCWB was most active at pH 8, had peak activity at 10 mM NaCl, 40% activity at 150 mM NaCl and was still 16% active at 600 mM NaCl. The protein was able to withstand temperatures up to 50° C and still lyse C. perfringens. Herein, we report the construction and characterization of a thermostable chimeric endolysin that could potentially be utilized as a feed additive to control the bacterium during poultry production.

  16. METHODS OF OBTAINING LONGITUDINAL STRIPES LAYOUTS

    Directory of Open Access Journals (Sweden)

    OANA Dorina

    2014-05-01

    Full Text Available From the technological point of view it is necessary that the phase of warping to be done two or three multiple warp, which results in two or three rolls of the warp final will meet only the warping. To achieve longitudinal striped fabric spinning machines is necessary to have all tensioning mechanism dispensing rolls which requires their special construction. The homogeneity of the fabric from the point of view of the warp yarns tension must be ensured by synchronizing operation of the tensioning two cutting mechanisms of the two reels on which the wires are wound with a degree of waving and thus the fuel consumption at the different weaving. It is recommended that the design be adopted average float bonds, such that the wires can be wrapped around more than two final reels. In terms of manufacturing technology with longitudinal stripes fabrics have a more complicated and expensive technology to cross-striped fabrics for the manufacture of which technology is simplified. Cross-striped fabrics containing groups of warp threads those linked to floating average is materially different. Due to this degree of crimping of wires in the stripes with different bonds makes their contract to be different, having a direct influence on the wires consumption. The different contraction of wire weaving makes warp yarn length, contained in a linked reports are so different that it requires winding wires with different bonds also differing on the final rolls.

  17. Bioinspired Heterogeneous Structural Color Stripes from Capillaries.

    Science.gov (United States)

    Zhao, Ze; Wang, Huan; Shang, Luoran; Yu, Yunru; Fu, Fanfan; Zhao, Yuanjin; Gu, Zhongze

    2017-12-01

    As an important characteristic of many creatures, structural colors play a crucial role in the survival of organisms. Inspired by these features, an intelligent structural color material with a heterogeneous striped pattern and stimuli-responsivity by fast self-assembly of colloidal nanoparticles in capillaries with a certain diameter range are presented here. The width, spacing, color, and even combination of the structural color stripe patterns can be precisely tailored by adjusting the self-assembly parameters. Attractively, with the integration of a near-infrared (NIR) light responsive graphene hydrogel into the structural color stripe pattern, the materials are endowed with light-controlled reversible bending behavior with self-reporting color indication. It is demonstrated that the striped structural color materials can be used as NIR-light-triggered dynamic barcode labels for the anti-counterfeiting of different products. These features of the bioinspired structural color stripe pattern materials indicate their potential values for mimicking structural color organisms, which will find important applications in constructing intelligent sensors, anti-counterfeiting devices, and so on. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Guiding thermomagnetic avalanches with soft magnetic stripes

    Energy Technology Data Exchange (ETDEWEB)

    Vlasko-Vlasov, V. K.; Colauto, F.; Benseman, T.; Rosenmann, D.; Kwok, W. -K.

    2017-12-01

    We demonstrate the potential for manipulating the ultrafast dynamics of thermomagnetic flux avalanches (TMA) in superconducting films with soft magnetic stripes deposited on the film. By tuning the in-plane magnetization of the stripes, we induce lines of strong magnetic potentials for Abrikosov vortices, resulting in guided slow motion of vortices along the stripe edges and preferential bursts of TMA along the stripes. Furthermore, we show that transversely polarized stripes can reduce the TMA size by diverting magnetic flux away from the major trunk of the TMA into interstripe gaps. Our data indicate that TMAs are launched from locations with enhanced vortex entry barrier, where flux accumulation followed by accelerated vortex discharge significantly reduces the threshold of the applied field ramping speed required for the creation of TMAs. Finally, vortex-antivortex annihilation at the moving front of an expanding TMA can account for the enhanced TMA activity in the receding branches of the sample's magnetization cycle and the preferred propagation of TMAs into maximum trapped flux regions.

  19. B-meson decay constants from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    Energy Technology Data Exchange (ETDEWEB)

    Christ, Norman H. [Columbia Univ., New York, NY (United States); Flynn, Jonathan M. [Univ. of Southampton, Southampton (United Kingdom); Izubuchi, Taku [Brookhaven National Lab. (BNL), Upton, NY (United States); Kawanai, Taichi [RIKEN, Wako (Japan); Brookhaven National Lab. (BNL), Upton, NY (United States); Lehner, Christoph [Brookhaven National Lab. (BNL), Upton, NY (United States); Soni, Amarjit [Brookhaven National Lab. (BNL), Upton, NY (United States); Van de Water, Ruth S. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Witzel, Oliver [Boston Univ., Boston, MA (United States)

    2015-03-10

    We calculate the B-meson decay constants fB, fBs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as Mπ ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b-quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(αsa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain fB0 = 196.2(15.7) MeV, fB+ = 195.4(15.8) MeV, fBs = 235.4(12.2) MeV, fBs/fB0 = 1.193(59), and fBs/fB+ = 1.220(82), where the errors are statistical and total systematic added in quadrature. In addition, these results are in good agreement with other published results and provide an important independent cross check of other three-flavor determinations of B-meson decay constants using staggered light quarks.

  20. Domain wall and interphase boundary motion in (1−x)Bi(Mg{sub 0.5}Ti{sub 0.5})O{sub 3}–xPbTiO{sub 3} near the morphotropic phase boundary

    Energy Technology Data Exchange (ETDEWEB)

    Tutuncu, Goknur [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Chen, Jun; Fan, Longlong [Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Fancher, Chris M.; Zhao, Jianwei [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Forrester, Jennifer S.; Jones, Jacob L., E-mail: JacobJones@ncsu.edu [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2016-07-28

    Electric field-induced changes in the domain wall motion of (1−x)Bi(Mg{sub 0.5}Ti{sub 0.5})O{sub 3}–xPbTiO{sub 3} (BMT-xPT) near the morphotropic phase boundary (MPB) where x = 0.37 (BMT-37PT) and x = 0.38 (BMT-38PT), are studied by means of synchrotron x-ray diffraction. Through Rietveld analysis and profile fitting, a mixture of coexisting monoclinic (Cm) and tetragonal (P4mm) phases is identified at room temperature. Extrinsic contributions to the property coefficients are evident from electric-field-induced domain wall motion in both the tetragonal and monoclinic phases, as well as through the interphase boundary motion between the two phases. Domain wall motion in the tetragonal and monoclinic phases for BMT-37PT is larger than that of BMT-38PT, possibly due to this composition's closer proximity to the MPB. Increased interphase boundary motion was also observed in BMT-37PT. Lattice strain, which is a function of both intrinsic piezoelectric strain and elastic interactions of the grains (the latter originating from domain wall and interphase boundary motion), is similar for the respective tetragonal and monoclinic phases.

  1. The IAC stripe82 legacy project

    Science.gov (United States)

    Román, Javier; Fliri, Juergen; Trujillo, Ignacio

    2017-03-01

    We present new deep co-adds of data taken within Stripe 82 of the Sloan Digital Sky Survey (SDSS), especially stacked to reach the faintest surface brightness limits of this data set. Our reduction puts special emphasis on preserving the characteristics of the background (sky + diffuse light) in the input images using a non-aggressive sky subtraction strategy, resulting in an exquisite quality on extremely faint structures. The IAC Stripe 82 co-adds offer a rather unique possibility to study the low surface brightness Universe like stellar haloes and disc truncations, low surface brightness, tidal galactic interactions, extremely faint dwarf galaxies, intra-cluster light or diffuse light from galactic dust. The imaging data is publicly available at http://www.iac.es/proyecto/stripe82/.

  2. Improving striping operations through system optimization - phase 2 : final report.

    Science.gov (United States)

    2016-07-01

    Striping operations generate a significant workload for MoDOT maintenance operations. The requirement for each striping crew : to replenish its stock of paint and other consumable items from a bulk storage facility, along with the necessity to make s...

  3. First results from 2+1-Flavor Domain Wall QCD: Mass Spectrum, Topology Change and Chiral Symmetry with $L_s=8$

    Energy Technology Data Exchange (ETDEWEB)

    D. J. Antonio; T. Blum; K. C. Bowler; P. A. Boyle; N. H. Christ; S. D. Cohen; M. A. Clark; C. Dawson; A. Hart; K. Hashimoto; T. Izubuchi; B. Joó; C. Jung; A. D. Kennedy; R. D. Kenway; S. Li; H. W. Lin; M.F. Lin; R. D. Mawhinney; C.M. Maynard; J. Noaki; S. Ohta; S. Sasaki; A. Soni; R. J. Tweedie; A. Yamaguchi

    2007-06-01

    We present results for the static interquark potential, light meson and baryon masses, and light pseudoscalar meson decay constants obtained from simulations of domain wall QCD with one dynamical flavour approximating the $s$ quark, and two degenerate dynamical flavours with input bare masses ranging from $m_s$ to $m_s/4$ approximating the $u$ and $d$ quarks. We compare these quantities obtained using the Iwasaki and DBW2 improved gauge actions, and actions with larger rectangle coefficients, on $16^3\\times32$ lattices. We seek parameter values at which both the chiral symmetry breaking residual mass due to the finite lattice extent in the fifth dimension and the Monte Carlo time history for topological charge are acceptable for this set of quark masses at lattice spacings above 0.1 fm. We find that the Iwasaki gauge action is best, demonstrating the feasibility of using QCDOC to generate ensembles which are good representations of the QCD path integral on lattices of up to 3 fm in spatial extent with lattice spacings in the range 0.09-0.13 fm. Despite large residual masses and a limited number of sea quark mass values with which to perform chiral extrapolations, our results for light hadronic physics scale and agree with experimental measurements within our statistical uncertainties.

  4. Comparison between collective coordinate models for domain wall motion in PMA nanostrips in the presence of the Dzyaloshinskii-Moriya interaction

    Science.gov (United States)

    Vandermeulen, J.; Nasseri, S. A.; Van de Wiele, B.; Durin, G.; Van Waeyenberge, B.; Dupré, L.

    2018-03-01

    Lagrangian-based collective coordinate models for magnetic domain wall (DW) motion rely on an ansatz for the DW profile and a Lagrangian approach to describe the DW motion in terms of a set of time-dependent collective coordinates: the DW position, the DW magnetization angle, the DW width and the DW tilting angle. Another approach was recently used to derive similar equations of motion by averaging the Landau-Lifshitz-Gilbert equation without any ansatz, and identifying the relevant collective coordinates afterwards. In this paper, we use an updated version of the semi-analytical equations to compare the Lagrangian-based collective coordinate models with micromagnetic simulations for field- and STT-driven (spin-transfer torque-driven) DW motion in Pt/CoFe/MgO and Pt/Co/AlOx nanostrips. Through this comparison, we assess the accuracy of the different models, and provide insight into the deviations of the models from simulations. It is found that the lack of terms related to DW asymmetry in the Lagrangian-based collective coordinate models significantly contributes to the discrepancy between the predictions of the most accurate Lagrangian-based model and the micromagnetic simulations in the field-driven case. This is in contrast to the STT-driven case where the DW remains symmetric.

  5. Probing optically silent superfluid stripes in cuprates

    Science.gov (United States)

    Rajasekaran, S.; Okamoto, J.; Mathey, L.; Fechner, M.; Thampy, V.; Gu, G. D.; Cavalleri, A.

    2018-02-01

    In many theoretical models of high-temperature superconductors, remnants of superconductivity persist to temperatures higher than the transition temperature, TC. Rajasekaran et al. used nonlinear terahertz spectroscopy to probe this region of the phase diagram of a cuprate superconductor that is well known for a stripe phase that appears for certain doping levels (see the Perspective by Ergeçen and Gedik). For a sample deep in the stripe phase, a large nonlinear signal persisted from the superconducting region up to temperatures much higher than TC. The findings suggest the formation of a peculiar spatially modulated superconducting state called the pair-density wave.

  6. DNA methylation profiles correlated to striped bass sperm fertility

    Science.gov (United States)

    Striped bass (Morone saxatilis) spermatozoa are used to fertilize in vitro the eggs of white bass (Morone chrysops) to produce the preferred hybrid for the striped bass aquaculture industry. Currently, only one source of domestic striped bass juveniles are available to growers that are not obtained ...

  7. substitution line for resistance to stripe rust

    Indian Academy of Sciences (India)

    2011-08-19

    Aug 19, 2011 ... c Indian Academy of Sciences. RESEARCH ARTICLE. Molecular cytogenetic characterization of a new wheat Secale africanum. 2R a. (2D) substitution line for resistance to stripe rust. MENGPING LEI, GUANGRONG LI, SUFEN ZHANG, CHENG LIU and ZUJUN YANG. ∗. School of Life Science and ...

  8. Breakup Behavior of a Capillary Bridge on a Hydrophobic Stripe Separating Two Hydrophilic Stripes

    Science.gov (United States)

    Hartmann, Maximilian; Hardt, Steffen

    2017-11-01

    The breakup dynamics of a capillary bridge on a hydrophobic area between two liquid filaments occupying two parallel hydrophilic stripes is studied experimentally. In addition calculations with the finite-element software Surface Evolver are performed to obtain the corresponding stable minimal surfaces. Droplets of de-ionized water are placed on substrates with alternating hydrophilic and hydrophobic stripes of different width. Their volume decreases by evaporation. This results in a droplet shaped as the letter ``H'' covering two hydrophilic stripes separated by one hydrophobic stripe. The width of the capillary bridge d(t) on the hydrophobic stripe during the breakup process is observed using a high-speed camera mounted on a bright-field microscope. The results of the experiments and the numerical studies show that the critical width dcrit, indicating the point where the capillary bridge becomes unstable, mainly depends on the width ratio of the hydrophilic and hydrophobic stripes. It is found that the time derivative of d(t) first decreases after dcrit has been reached. The final breakup dynamics then follows a t 2 / 3 scaling. We kindly acknowledge the financial support by the German Research Foundation (DFG) within the Collaborative Research Centre 1194 ``Interaction of Transport and Wetting Processes'', Project A02a.

  9. Single-domain epitaxial silicene on diboride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Fleurence, A., E-mail: antoine@jaist.ac.jp; Friedlein, R.; Aoyagi, K.; Yamada-Takamura, Y. [School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Gill, T. G. [School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH (United Kingdom); Department of Chemistry, UCL, London WC1H 0AJ (United Kingdom); Sadowski, J. T. [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973 (United States); Copel, M.; Tromp, R. M. [IBM Research Division, Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Hirjibehedin, C. F. [London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH (United Kingdom); Department of Chemistry, UCL, London WC1H 0AJ (United Kingdom); Department of Physics and Astronomy, UCL, London WC1E 6BT (United Kingdom)

    2016-04-11

    Epitaxial silicene, which forms spontaneously on ZrB{sub 2}(0001) thin films grown on Si(111) wafers, has a periodic stripe domain structure. By adsorbing additional Si atoms on this surface, we find that the domain boundaries vanish, and a single-domain silicene sheet can be prepared without altering its buckled honeycomb structure. The amount of Si required to induce this change suggests that the domain boundaries are made of a local distortion of the silicene honeycomb lattice. The realization of a single domain sheet with structural and electronic properties close to those of the original striped state demonstrates the high structural flexibility of silicene.

  10. Effect of Electric Field and Temperature on Average Structure and Domain Wall Motion in 0.93Bi0.5Na0.5TiO3-0.07BaTiO3 Ceramic

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2013-01-01

    Full Text Available In situ neutron powder diffraction patterns and dielectric spectra of 0.93Bi0.5Na0.5TiO3-0.07BaTiO3 ceramic were investigated under different electrical fields and temperatures. An electric-field-induced phase transition from metrically cubic to metrically tetragonal, associated with strong domain wall motion, occurs. Such induced phase and domain wall motion are unchanged until the high-temperature phase transition occurs from metrically tetragonal to metrically cubic. All these changes are irrelevant to the observed depolarization temperature (75°C. The depolarization behaviour is thus suggested to be associated with the local structure caused by the octahedral tilt twinning disorder.

  11. STRIPE: Remote Driving Using Limited Image Data

    Science.gov (United States)

    Kay, Jennifer S.

    1997-01-01

    Driving a vehicle, either directly or remotely, is an inherently visual task. When heavy fog limits visibility, we reduce our car's speed to a slow crawl, even along very familiar roads. In teleoperation systems, an operator's view is limited to images provided by one or more cameras mounted on the remote vehicle. Traditional methods of vehicle teleoperation require that a real time stream of images is transmitted from the vehicle camera to the operator control station, and the operator steers the vehicle accordingly. For this type of teleoperation, the transmission link between the vehicle and operator workstation must be very high bandwidth (because of the high volume of images required) and very low latency (because delayed images can cause operators to steer incorrectly). In many situations, such a high-bandwidth, low-latency communication link is unavailable or even technically impossible to provide. Supervised TeleRobotics using Incremental Polyhedral Earth geometry, or STRIPE, is a teleoperation system for a robot vehicle that allows a human operator to accurately control the remote vehicle across very low bandwidth communication links, and communication links with large delays. In STRIPE, a single image from a camera mounted on the vehicle is transmitted to the operator workstation. The operator uses a mouse to pick a series of 'waypoints' in the image that define a path that the vehicle should follow. These 2D waypoints are then transmitted back to the vehicle, where they are used to compute the appropriate steering commands while the next image is being transmitted. STRIPE requires no advance knowledge of the terrain to be traversed, and can be used by novice operators with only minimal training. STRIPE is a unique combination of computer and human control. The computer must determine the 3D world path designated by the 2D waypoints and then accurately control the vehicle over rugged terrain. The human issues involve accurate path selection, and the

  12. The preparation of immunochromatographic stripe of methamphetamine

    International Nuclear Information System (INIS)

    Jiang Jing; Liu Yibing; Zhou Ling; Guo Weizheng

    2004-01-01

    A gold immunochromatographic assay (GICA) is developed for methamphetamine in urine. Colloidal gold is obtained by reducing the gold chloride with sodium citrate, and labeled methamphetamine monoclonal antibody. The drug or metabolite competes with the immobilized drug conjugate in the test area for the limited colloidal gold-labeled antibody complex in which the stripe is made to screen the drug abuser. This method has sensitivity of 1000 μg/L, and without cross-reaction with some drugs

  13. 3D face recognition using isogeodesic stripes.

    Science.gov (United States)

    Berretti, Stefano; Del Bimbo, Alberto; Pala, Pietro

    2010-12-01

    In this paper, we present a novel approach to 3D face matching that shows high effectiveness in distinguishing facial differences between distinct individuals from differences induced by nonneutral expressions within the same individual. The approach takes into account geometrical information of the 3D face and encodes the relevant information into a compact representation in the form of a graph. Nodes of the graph represent equal width isogeodesic facial stripes. Arcs between pairs of nodes are labeled with descriptors, referred to as 3D Weighted Walkthroughs (3DWWs), that capture the mutual relative spatial displacement between all the pairs of points of the corresponding stripes. Face partitioning into isogeodesic stripes and 3DWWs together provide an approximate representation of local morphology of faces that exhibits smooth variations for changes induced by facial expressions. The graph-based representation permits very efficient matching for face recognition and is also suited to being employed for face identification in very large data sets with the support of appropriate index structures. The method obtained the best ranking at the SHREC 2008 contest for 3D face recognition. We present an extensive comparative evaluation of the performance with the FRGC v2.0 data set and the SHREC08 data set.

  14. Classifying Variable Sources in SDSS Stripe 82

    Science.gov (United States)

    Willecke Lindberg, Christina

    2018-01-01

    SDSS (Sloan Digital Sky Survey) Stripe 82 is a well-documented and researched region of the sky that does not have all of its ~67,500 variable objects labeled. By collecting data and consulting different catalogs such as the Catalina Survey, we are able to slowly cross-match more objects and add classifications within the Stripe 82 catalog. Such matching is performed either by pairing SDSS identification numbers, or by converting and comparing the coordinates of every object within the Stripe 82 catalog to every object within the classified catalog, such as the Catalina Survey catalog. If matching is performed with converted coordinates, a follow-up check is performed to ascertain that the magnitudes of the paired objects are within a reasonable margin of error and that objects have not been mismatched. Once matches have been confirmed, the light curves of classified objects can then be used to determine features that most effectively separate the different types of variable objects in feature spaces. By classifying variable objects, we can construct a reference for subsequent large research surveys, such as LSST (the Large Synoptic Survey Telescope), that could utilize SDSS data as a training set for its own classifications.

  15. Occupational Noise Reduction in CNC Striping Process

    Science.gov (United States)

    Mahmad Khairai, Kamarulzaman; Shamime Salleh, Nurul; Razlan Yusoff, Ahmad

    2018-03-01

    Occupational noise hearing loss with high level exposure is common occupational hazards. In CNC striping process, employee that exposed to high noise level for a long time as 8-hour contributes to hearing loss, create physical and psychological stress that reduce productivity. In this paper, CNC stripping process with high level noises are measured and reduced to the permissible noise exposure. First condition is all machines shutting down and second condition when all CNC machine under operations. For both conditions, noise exposures were measured to evaluate the noise problems and sources. After improvement made, the noise exposures were measured to evaluate the effectiveness of reduction. The initial average noise level at the first condition is 95.797 dB (A). After the pneumatic system with leakage was solved, the noise reduced to 55.517 dB (A). The average noise level at the second condition is 109.340 dB (A). After six machines were gathered at one area and cover that area with plastic curtain, the noise reduced to 95.209 dB (A). In conclusion, the noise level exposure in CNC striping machine is high and exceed the permissible noise exposure can be reduced to acceptable levels. The reduction of noise level in CNC striping processes enhanced productivity in the industry.

  16. Explanation of the nature of stripe magnetic anomalies without inversions

    Science.gov (United States)

    Melikhov, Vjacheslav; Lygin, Ivan; Sokolova, Tatiana

    2014-05-01

    Several scientists of different branches express doubts on the validity of the Earth's geomagnetic field inversions hypothesis [Vine F.J., Matthews D.H, 1963]. Presently a lot of information allows to link the appearance of stripe magnetic anomalies of both signs with the spreading fracture structure (horizontal segmentation of intrusions and sills, breaks in the strong crust, vertical movements of blocks), remagnetization near the borders of the blocks, hydrothermal activity. Non-inversion mechanism of origin of linear stripe magnetic anomalies in the oceans could be explained as follows. Ascending asthenospheric flows have been enrich with volatile components, become thinner, pressure on the walls of the lithospheric plates grows and part them. When it approaches the surface: - horizontal tensile pressure grows, - lithostatic pressure in the vertical column of rocks decreases, - crust strong upper layer flakes away and begins to move horizontally. It is important that thin magmatic and magnetic layers (further layers) of the newly formed strong upper crust move away from the ridge axis. The structure of such layers forms by horizontal stresses and so consist of the hills and depressions sequences or updiped and downdiped blocks heaped each other. This layer is the main source of the magnetic field and cannot be approximated by a horizontal homogeneous plate as it proved before. In the mid-ocean ridges (MOR) the folding periods of layer depend on its thickness and rigidity and horizontal velocity of spreading. The higher velocity - the longer periods of roughness are and contrary. Same pattern is observed for the stripe magnetic anomalies distribution. The magnetic field of the MOR forms there due to young lava flows which get thermoremanent magnetization according the current direction of geomagnetic field. Partial destruction of the relief, overlaying and creation of the new shapes occur when new magma penetrates the moved magnetic layer. The process entails

  17. Visualization analysis of tiger-striped flow mark generation phenomena in injection molding

    Science.gov (United States)

    Owada, Shigeru; Yokoi, Hidetoshi

    2016-03-01

    The generation mechanism of tiger-striped flow marks of polypropylene (PP)/rubber/talc blends in injection molding was investigated by dynamic visualization analysis in a glass-inserted mold. The analysis revealed that the behavior of the melt flow front correlates with the flow mark generation. The cloudy part in the tiger-striped flow marks corresponded to the low transcription rate area of the melt diverging near the cavity wall, while the glossy part corresponded to the high transcription rate area of the melt converging toward the cavity wall side. The melt temperature at the high transcription rate area was slightly lower than that at the low transcription rate area. These phenomena resulted due to the difference in the temperature of the melt front that was caused by the asymmetric fountain flow. These results suggest the followings; At the moment when the melt is broken near the one side of cavity wall due to piling the extensional strains up to a certain level, the melt spurts out near the broken side. It results in generating asymmetric fountain flow temporarily to relax the extensional front surface, which moves toward the opposite side to form the high transcription area.

  18. Inhomogeneous Stripe Phase Revisited for Surface Superconductivity

    Science.gov (United States)

    Barzykin, Victor; Gor'kov, Lev P.

    2002-11-01

    We consider 2D surface superconductivity in high magnetic fields parallel to the surface. We demonstrate that the spin-orbit interaction at the surface changes the properties of the inhomogeneous superconducting Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) state that develops above fields given by the paramagnetic criterion. Strong spin-orbit interaction significantly broadens the range of existence of the LOFF phase, which takes the form of periodic superconducting stripes running along the field direction on the surface, leading to the anisotropy of its properties. Our results provide a tool for studying surface superconductivity as a function of doping.

  19. leaf and stripe rust resistance among ethiopian grown wheat ...

    African Journals Online (AJOL)

    ADMIN

    pathogen pathotypes. These varieties and lines, therefore, may be utilized in leaf and stripe rust resistance breeding programs. Key words/phrases: Leaf rust, resistance, stripe rust, Triticum aestivum, Triticum turgidum. * Current address: University of Limpopo, School of Agricultural and Environmental Sciences, Private Bag ...

  20. Transfer of stripe rust resistance from Aegilops variabilis to bread ...

    African Journals Online (AJOL)

    In terms of area, the bread wheat producing regions of China comprise the largest area in the world that is constantly threatened by stripe rust epidemics. Consequently, it is important to exploit new adultplant resistance genes in breeding. This study reports the transfer of stripe rust resistance from Aegilops variabilis to ...

  1. Competing States in the t-J Model: Uniform d-Wave State versus Stripe State versus Stripe State

    NARCIS (Netherlands)

    Corboz, P.R.; Rice, T.M.; Troyer, M.

    2014-01-01

    Variational studies of the t-J model on the square lattice based on infinite projected-entangled pair states confirm an extremely close competition between a uniform d-wave superconducting state and different stripe states. The site-centered stripe with an in-phase d-wave order has an equal or only

  2. Theoretical and experimental investigations of efficient light coupling with spatially varied all dielectric striped waveguides

    Science.gov (United States)

    Yilmaz, Y. A.; Tandogan, S. E.; Hayran, Z.; Giden, I. H.; Turduev, M.; Kurt, H.

    2017-07-01

    Integrated photonic systems require efficient, compact, and broadband solutions for strong light coupling into and out of optical waveguides. The present work investigates an efficient optical power transferring the problem between optical waveguides having different widths of in/out terminals. We propose a considerably practical and feasible concept to implement and design an optical coupler by introducing gradually index modulation to the coupler section. The index profile of the coupler section is modulated with a Gaussian function by the help of striped waveguides. The effective medium theory is used to replace the original spatially varying index profile with dielectric stripes of a finite length/width having a constant effective refractive index. 2D and 3D finite-difference time-domain analyzes are utilized to investigate the sampling effect of the designed optical coupler and to determine the parameters that play a crucial role in enhancing the optical power transfer performance. Comparing the coupling performance of conventional benchmark adiabatic and butt couplers with the designed striped waveguide coupler, the corresponding coupling efficiency increases from approximately 30% to 95% over a wide frequency interval. In addition, to realize the realistic optical coupler appropriate to integrated photonic applications, the proposed structure is numerically designed on a silicon-on-insulator wafer. The implemented SOI platform based optical coupler operates in the telecom wavelength regime (λ = 1.55 μm), and the dimensions of the striped coupler are kept as 9.77 μm (along the transverse to propagation direction) and 7.69 μm (along the propagation direction) where the unit distance is fixed to be 465 nm. Finally, to demonstrate the operating design principle, the microwave experiments are conducted and the spot size conversion ratio as high as 7.1:1 is measured, whereas a coupling efficiency over 60% in the frequency range of 5.0-16.0 GHz has been also

  3. Critical assessment of the evidence for striped nanoparticles.

    Directory of Open Access Journals (Sweden)

    Julian Stirling

    Full Text Available There is now a significant body of literature which reports that stripes form in the ligand shell of suitably functionalised Au nanoparticles. This stripe morphology has been proposed to strongly affect the physicochemical and biochemical properties of the particles. We critique the published evidence for striped nanoparticles in detail, with a particular focus on the interpretation of scanning tunnelling microscopy (STM data (as this is the only technique which ostensibly provides direct evidence for the presence of stripes. Through a combination of an exhaustive re-analysis of the original data, in addition to new experimental measurements of a simple control sample comprising entirely unfunctionalised particles, we show that all of the STM evidence for striped nanoparticles published to date can instead be explained by a combination of well-known instrumental artefacts, or by issues with data acquisition/analysis protocols. We also critically re-examine the evidence for the presence of ligand stripes which has been claimed to have been found from transmission electron microscopy, nuclear magnetic resonance spectroscopy, small angle neutron scattering experiments, and computer simulations. Although these data can indeed be interpreted in terms of stripe formation, we show that the reported results can alternatively be explained as arising from a combination of instrumental artefacts and inadequate data analysis techniques.

  4. Critical assessment of the evidence for striped nanoparticles.

    Science.gov (United States)

    Stirling, Julian; Lekkas, Ioannis; Sweetman, Adam; Djuranovic, Predrag; Guo, Quanmin; Pauw, Brian; Granwehr, Josef; Lévy, Raphaël; Moriarty, Philip

    2014-01-01

    There is now a significant body of literature which reports that stripes form in the ligand shell of suitably functionalised Au nanoparticles. This stripe morphology has been proposed to strongly affect the physicochemical and biochemical properties of the particles. We critique the published evidence for striped nanoparticles in detail, with a particular focus on the interpretation of scanning tunnelling microscopy (STM) data (as this is the only technique which ostensibly provides direct evidence for the presence of stripes). Through a combination of an exhaustive re-analysis of the original data, in addition to new experimental measurements of a simple control sample comprising entirely unfunctionalised particles, we show that all of the STM evidence for striped nanoparticles published to date can instead be explained by a combination of well-known instrumental artefacts, or by issues with data acquisition/analysis protocols. We also critically re-examine the evidence for the presence of ligand stripes which has been claimed to have been found from transmission electron microscopy, nuclear magnetic resonance spectroscopy, small angle neutron scattering experiments, and computer simulations. Although these data can indeed be interpreted in terms of stripe formation, we show that the reported results can alternatively be explained as arising from a combination of instrumental artefacts and inadequate data analysis techniques.

  5. Wheat stripe rust resistance protein WKS1 reduces the ability of the thylakoid-associated ascorbate peroxidase to detoxify reactive oxygen species

    Science.gov (United States)

    Stripe rust is a devastating fungal disease of wheat caused by Puccinia striiformis f. sp. tritici(Pst). The WKS1 resistance gene has an unusual combination of serine/threonine kinase and START lipid-binding domains and confers partial resistance to Pst. Here we show that wheat plants transformed w...

  6. Scaling behavior of thin films on chemically heterogeneous walls

    Science.gov (United States)

    Malijevský, Alexandr; Parry, Andrew O.; Pospíšil, Martin

    2017-09-01

    We study the adsorption of a fluid in the grand canonical ensemble occurring at a planar heterogeneous wall which is decorated with a chemical stripe of width L . We suppose that the material of the stripe strongly preferentially adsorbs the liquid in contrast to the outer material which is only partially wet. This competition leads to the nucleation of a droplet of liquid on the stripe, the height hm and shape of which (at bulk two-phase coexistence) has been predicted previously using mesoscopic interfacial Hamiltonian theory. We test these predictions using a microscopic Fundamental Measure Density Functional Theory which incorporates short-ranged fluid-fluid and fully long-ranged wall-fluid interactions. Our model functional accurately describes packing effects not captured by the interfacial Hamiltonian but still we show that there is excellent agreement with the predictions hm≈L1 /2 and for the scaled circular shape of the drop even for L as small as 50 molecular diameters. For smaller stripes the droplet height is considerably lower than that predicted by the mesoscopic interfacial theory. Phase transitions for droplet configurations occurring on substrates with multiple stripes are also discussed.

  7. Stripe order from the perspective of the Hubbard model

    Energy Technology Data Exchange (ETDEWEB)

    Devereaux, Thomas Peter

    2018-03-01

    A microscopic understanding of the strongly correlated physics of the cuprates must account for the translational and rotational symmetry breaking that is present across all cuprate families, commonly in the form of stripes. Here we investigate emergence of stripes in the Hubbard model, a minimal model believed to be relevant to the cuprate superconductors, using determinant quantum Monte Carlo (DQMC) simulations at finite temperatures and density matrix renormalization group (DMRG) ground state calculations. By varying temperature, doping, and model parameters, we characterize the extent of stripes throughout the phase diagram of the Hubbard model. Our results show that including the often neglected next-nearest-neighbor hopping leads to the absence of spin incommensurability upon electron-doping and nearly half-filled stripes upon hole-doping. The similarities of these findings to experimental results on both electron and hole-doped cuprate families support a unified description across a large portion of the cuprate phase diagram.

  8. Curcurbita pepo subspecies delineates striped cucumber beetle (Acalymma vittatum) preference

    Science.gov (United States)

    Brzozowski, L; Leckie, B M; Gardner, J; Hoffmann, M P; Mazourek, M

    2016-01-01

    The striped cucumber beetle (Acalymma vittatum (F.)) is a destructive pest of cucurbit crops, and management could be improved by host plant resistance, especially in organic farming systems. However, despite the variation in striped cucumber beetle preference observed within the economically important species, Cucurbita pepo L., plant breeders and entomologists lacked a simple framework to classify and exploit these differences. This study used recent phylogenetic evidence and bioassays to organize striped cucumber beetle preference within C. pepo. Our results indicate preference contrasts between the two agriculturally relevant subspecies: C. pepo subsp. texana and C. pepo subsp. pepo. Plants of C. pepo subsp. pepo were more strongly preferred than C. pepo subsp. texana plants. This structure of beetle preference in C. pepo will allow plant breeders and entomologists to better focus research efforts on host plant non-preference to control striped cucumber beetles. PMID:27347423

  9. Pathological changes associated with white striping in broiler breast muscles.

    Science.gov (United States)

    Kuttappan, V A; Shivaprasad, H L; Shaw, D P; Valentine, B A; Hargis, B M; Clark, F D; McKee, S R; Owens, C M

    2013-02-01

    White striping is a condition in broiler chickens characterized grossly by the occurrence of white striations, seen parallel to the direction of muscle fibers, on broiler breast fillets and thighs. Based on visual evaluation of the intensity of white striping, breast fillets can be categorized into normal (NORM), moderate (MOD), and severe (SEV) categories. This study was undertaken to evaluate the details of changes in histology as well as proximate composition occurring in the fillets with respect to the 3 degrees of white striping. In experiment 1, representative breast fillets for each degree of white striping (n = 20) were collected from 45-d-old broilers, approximately 2 h postmortem. From each fillet, 2 skeletal muscle samples were obtained and fixed in 10% neutral buffered formalin. To identify and differentiate the histological changes, slides were prepared and stained using hematoxylin and eosin, Masson's Trichrome, and Oil Red O stains. In experiment 2, samples with 3 degrees of white striping were collected from 57-d-old birds for conducting proximate analysis. Major histopathological changes observed in the MOD and SEV samples consisted of loss of cross striations, variability in fiber size, floccular/vacuolar degeneration and lysis of fibers, mild mineralization, occasional regeneration (nuclear rowing and multinucleated cells), mononuclear cell infiltration, lipidosis, and interstitial inflammation and fibrosis. Microscopic lesions were visually scored for degeneration and necrosis, fibrosis, and lipidosis. The scale used to score the samples ranged from 0 (normal) to 3 (severe). There was an increase (P white striping increased from NORM to SEV. The results from the histopathological study were supported by the findings from proximate analysis confirming that the fat and protein contents of muscle increased (P white striping increased. In conclusion, the histopathological changes occurring in white striping indicate a degenerative myopathy that

  10. Domain wall motion and magnetization reversal processes in a FeSi picture frame single crystal studied by the time-dependent neutron depolarization technique

    International Nuclear Information System (INIS)

    Schaik, F.J. van.

    1979-01-01

    The three dimensional neutron depolarization technique, which gives detailed information about the static properties of ferromagnetic materials, has been extended to a method by means of which the time dependence of magnetic phenomena can be studied. The measurement of the neutron depolarization against time is made possible by applying a periodical magnetic field on the investigated specimen and by continuous sampling of the transmitted neutron intensity in time channels, which are started synchronously with the applied field. The technique has been used in the study of the magnetic domain structure at room temperature of a (010) [001] picture frame FeSi single crystal (3.5 wt.% Si) with outer dimensions of (15 x 10 x 0.26) mm and a frame width of 2.78 mm. (Auth.)

  11. Plasma-wall interactions in tokamaks, a scope between physics and chemistry; Interactions plasma-paroi dans les tokamaks. Un domaine a l'interface de la physique et de la chimie

    Energy Technology Data Exchange (ETDEWEB)

    Brosset, Ch. [CEA Cadarache, Dept. de Recherches sur la Fusion Controlee, 13 - Saint-Paul-lez-Durance (France); Allouche, A. [Centre National de la Recherche Scientifique (CNRS), Lab. de Physique des Interactions Ioniques et Moleculaires, 13 - Marseille (France)

    2005-09-01

    Remarkable results have been obtained in thermonuclear fusion researches since the first experiments performed in tokamaks, about 40 years ago. The next step is now to succeed in controlling deuterium-tritium long discharges in order to demonstrate the feasibility of fusion energy for peaceful purposes. This is the aim of ITER (International Thermonuclear Experimental Reactor), the next magnetic fusion device. While great progresses have been made, new questions emerged and the plasma-wall interactions are one of them. In this paper, we show that this domain is interdisciplinary, particularly because of the presence of carbon and hydrogen. Indeed, we highlight the fundamental role played by chemical processes in the interactions between hydrogen and carbon-based materials and the beneficial contribution of quantum-modelling works in the understanding of them. Ab initio calculations, using the density functional theory, allow studying chemical reactivity of the concerned species. Elementary processes and associated energies can be investigated without any empirical assumptions. The understanding of the elementary reactions, the calculation of the energy transfer and barriers of reaction, together with the modelling of reactions through quantum molecular dynamics provide helpful and more realistic input data to plasma-wall interaction simulation codes. (authors)

  12. Magnetic vortex state and multi-domain pattern in electrodeposited hemispherical nanogranular nickel films

    International Nuclear Information System (INIS)

    Samardak, Alexander; Sukovatitsina, Ekaterina; Ognev, Alexey; Stebliy, Maksim; Davydenko, Alexander; Chebotkevich, Ludmila; Keun Kim, Young; Nasirpouri, Forough; Janjan, Seyed-Mehdi; Nasirpouri, Farzad

    2014-01-01

    Magnetic states of nickel nanogranular films were studied in two distinct structures of individual and agglomerated granules electrodeposited on n-type Si(1 1 1) surface from a modified Watts bath at a low pH of 2. Magnetic force microscopy and micromagnetic simulations revealed three-dimensional out-of-plane magnetic vortex states in stand-alone hemispherical granules and their arrays, and multi-domain patterns in large agglomerates and integrated films. Once the granules coalesce into small chains or clusters, the coercivity values increased due to the reduction of inter-granular spacing and strengthening of the magnetostatic interaction. Further growth leads to the formation of a continuous granulated film which strongly affected the coercivity and remanence. This was characterized by the domain wall nucleation and propagation leading to a stripe domain pattern. Magnetoresistance measurements as a function of external magnetic field are indicative of anisotropic magnetoresistance (AMR) for the continuous films electrodeposited on Si substrate. - Highlights: • Magnetic states of electrodeposited nickel in isolated spherical and agglomerated nanogranules, and a continuous film. • Preferential magnetization reversal mechanism in isolated granules is vortex state. • Micromagnetic simulations confirm the three-dimensional vortex. • Transition between the vortex state and multi-domain magnetic pattern causes a significant decrease in the coercive force. • Continuous nickel films electrodeposited on silicon substrate exhibit AMR whose magnitude increases with the film thickness

  13. Development of structural response diagram approach to evaluation of thermal stress caused by thermal striping

    Energy Technology Data Exchange (ETDEWEB)

    Kasahara, Naoto; Yacumpai, Apisara [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center; Takasho, Hideki

    1999-02-01

    At incomplete mixing area of high temperature and low temperature fluids near the surface of structures, temperature fluctuation of fluid gives thermal fatigue damage to wall structures. This thermohydraulic and thermomechanical coupled phenomenon is called thermal striping, which has so complex mechanism and sometimes causes crack initiation on the structural surfaces that rational evaluation methods are required for screening rules in design codes. In this study, frequency response characteristics of structures and its mechanism were investigated by both numerical and theoretical methods. Based on above investigation, a structural response diagram was derived, which can predict stress amplitude of structures from temperature amplitude and frequency of fluids. Furthermore, this diagram was generalized to be the Non-dimensional structural response diagram by introducing non-dimensional parameters such as Biot number, non-dimensional frequency, and non-dimensional stress. The use of the Non-dimensional structural response diagram appears to evaluate thermal stress caused by thermal striping, rapidly without structural analysis, and rationally with considering attenuation by non-stationary heat transfer and thermal unloading. This diagram can also give such useful information as sensitive frequency range to adjust coupled thermohydraulic and thermomechanical analysis models taking account of four kinds of attenuation factors: turbulent mixing, molecular diffusion, non-stationary heat transfer, and thermal unloading. (author)

  14. Millijansky radio variability in SDSS stripe 82

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, J. A.; Becker, R. H. [University of California, 1 Shields Avenue, Davis, CA 95616 (United States); White, R. L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Richards, G. T., E-mail: hodge@mpia.de [Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States)

    2013-06-01

    We report on a blind survey for extragalactic radio variability that was carried out by comparing two epochs of data from the Faint Images of the Radio Sky at Twenty centimeters survey with a third epoch from a new 1.4 GHz survey of SDSS Stripe 82. The three epochs are spaced seven years apart and have an overlapping area of 60 deg{sup 2}. We uncover 89 variable sources down to the millijansky level, 75 of which are newly identified, and we find no evidence for transient phenomena. This new sample of variable sources allows us to infer an upper limit to the mean characteristic timescale of active galactic nucleus radio variability of 14 yr. We find that only 1% of extragalactic sources have fractional variability f {sub var} > 3, while 44% of Galactic sources vary by this much. The variable sample contains a larger fraction of quasars than a comparable non-variable control sample, though the majority of the variable sources appear to be extended galaxies in the optical. This implies that either quasars are not the dominant contributor to the variability of the sample, or that the deep optical data allow us to detect the host galaxies of some low-z quasars. We use the new, higher resolution data to report on the morphology of the variable sources. Finally, we show that the fraction of sources that are variable remains constant or increases at low flux densities. This may imply that next generation radio surveys with telescopes like Australian Square Kilometer Array Pathfinder and MeerKAT will see a constant or even increasing fraction of variable sources down into the sub-millijansky regime.

  15. Domains and domain loss

    DEFF Research Database (Denmark)

    Haberland, Hartmut

    2005-01-01

    politicians and in the media, especially in the discussion whether some languages undergo ‘domain loss’ vis-à-vis powerful international languages like English. An objection that has been raised here is that domains, as originally conceived, are parameters of language choice and not properties of languages...... not described in terms of domains, and recent research e.g. about the multilingual communities in the Danish-German border area seems to confirm this....

  16. From stripe to slab confinement for DNA linearization in nanochannels

    Science.gov (United States)

    Cifra, Peter; Benkova, Zuzana; Namer, Pavol

    We investigate suggested advantageous analysis in the linearization experiments with macromolecules confined in a stripe-like channel using Monte Carlo simulations. The enhanced chain extension in a stripe that is due to significant excluded volume interactions between monomers in two dimensions weakens on transition to experimentally feasible slit-like channel. Based on the chain extension-confinement strength dependence and the structure factor behavior for the chain in stripe we infer the excluded volume regime typical for two-dimensional systems. On transition to the slab geometry, the advantageous chain extension decreases and the Gaussian regime is observed for not very long semiflexible chains. The evidence for pseudo-ideality in confined chains is based on indicators such as the extension curves, variation of the extension with the persistence length or the structure factor. The slab behavior is observed when the stripe (originally of monomer thickness) reaches the thickness larger than cca 10nm in the third dimension. This maximum height of the slab to retain the advantage of the stripe is very low and this have implication for DNA linearization experiments. The presented analysis, however, has a broader relevance for confined polymers. Support from Slovak R&D Agency (SRDA-0451-11) is acknowledged.

  17. Roadway striping productivity data analysis for INDOT Greenfield and Crawfordsville districts.

    Science.gov (United States)

    2013-11-01

    The main objective of the SPR3650 project is to provide an accurate overview of striping operation so that INDOT finds a way to : effectively save significant investment for purchasing new striping trucks in near future without compromising roadwa...

  18. Twin InSb/GaAs quantum nano-stripes: Growth optimization and related properties

    Science.gov (United States)

    Narabadeesuphakorn, Phisut; Thainoi, Supachok; Tandaechanurat, Aniwat; Kiravittaya, Suwit; Nuntawong, Noppadon; Sopitopan, Suwat; Yordsri, Visittapong; Thanachayanont, Chanchana; Kanjanachuchai, Songphol; Ratanathammaphan, Somchai; Panyakeow, Somsak

    2018-04-01

    Growth of InSb/GaAs quantum nanostructures on GaAs substrate by using molecular beam epitaxy with low growth temperature and slow growth rate typically results in a mixture of isolated and paired nano-stripe structures, which are termed as single and twin nano-stripes, respectively. In this work, we investigate the growth conditions to maximize the number ratio between twin and single nano-stripes. The highest percentage of the twin nano-stripes of up to 59% was achieved by optimizing the substrate temperature and the nano-stripe growth rate. Transmission electron microscopy reveals the substantial size and height reduction of the buried nano-stripes. We also observed the Raman shift and photon emission from our twin nano-stripes. These twin nano-stripes are promising for spintronics and quantum computing devices.

  19. STRIPING NOISE REMOVAL OF IMAGES ACQUIRED BY CBERS 2 CCD CAMERA SENSOR

    Directory of Open Access Journals (Sweden)

    E. Amraei

    2014-10-01

    Full Text Available CCD Camera is a multi-spectral sensor that is carried by CBERS 2 satellite. Imaging technique in this sensor is push broom. In images acquired by the CCD Camera, some vertical striping noise can be seen. This is due to the detectors mismatch, inter detector variability, improper calibration of detectors and low signal-to-noise ratio. These noises are more profound in images acquired from the homogeneous surfaces, which are processed at level 2. However, the existence of these noises render the interpretation of the data and extracting information from these images difficult. In this work, spatial moment matching method is proposed to modify these images. In this method, the statistical moments such as mean and standard deviation of columns in each band are used to balance the statistical specifications of the detector array to those of reference values. After the removal of the noise, some periodic diagonal stripes remain in the image where their removal by using the aforementioned method seems impossible. Therefore, to omit them, frequency domain Butterworth notch filter was applied. Finally to evaluate the results, the image statistical moments such as the mean and standard deviation were deployed. The study proves the effectiveness of the method in noise removal.

  20. Magnetostatic Green's functions for the description of spin waves in finite rectangular magnetic dots and stripes

    International Nuclear Information System (INIS)

    Guslienko, Konstantin Y.; Slavin, Andrei N.

    2011-01-01

    We present derivation of the magnetostatic Green's functions used in calculations of spin-wave spectra of finite-size non-ellipsoidal (rectangular) magnetic elements. The elements (dots) are assumed to be single domain particles having uniform static magnetization. We consider the case of flat dots, when the in-plane dot size is much larger than the dot height (film thickness), and assume the uniform distribution of the variable magnetization along the dot height. The limiting cases of magnetic waveguides with rectangular cross-section and thin magnetic stripes are also considered. The developed method of tensorial Green's functions is used to solve the Maxwell equations in the magnetostatic limit, and to represent the Landau-Lifshitz equation of motion for the magnetization of a magnetic element in a closed integro-differential form. - Highlights: → The Green's functions method is used to solve the magnetostatic equations. → Explicit Green's functions are written for thin magnetic dots and stripes. → Spin-wave frequencies for finite rectangular magnetic elements are calculated.

  1. Distinguishing Patterns of Charge Order: Stripes or Checkerboards

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, J.A.

    2010-04-06

    In two dimensions, quenched disorder always rounds transitions involving the breaking of spatial symmetries so, in practice, it can often be difficult to infer what form the symmetry breaking would take in the 'ideal,' zero disorder limit. We discuss methods of data analysis which can be useful for making such inferences, and apply them to the problem of determining whether the preferred order in the cuprates is 'stripes' or 'checkerboards.' In many cases we show that the experiments clearly indicate stripe order, while in others (where the observed correlation length is short), the answer is presently uncertain.

  2. Visual acuity in the striped skunk (Mephitis mephitis).

    Science.gov (United States)

    Johnson-Ulrich, Zoe; Hoffmaster, Eric; Robeson, Audrey; Vonk, Jennifer

    2017-11-01

    The visual acuity of striped skunks (Mephitis mephitis) was tested using a 2 alternative forced-choice task with square wave gratings. Skunks were reinforced with food items for touching a ball in front of a striped stimulus when paired with a ball in front of a solid gray stimulus. Skunks demonstrated a maximum visual acuity of 0.42 cycles per degree when tested with bright outdoor illumination. This poor visual acuity may be due to their nocturnal lifestyle, lack of predation, and is consistent with their preferential use of smell and sound during foraging. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  3. 32 CFR Appendix E to Part 246 - Stars and Stripes (S&S) Board of Directors

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Stars and Stripes (S&S) Board of Directors E... DEFENSE (CONTINUED) MISCELLANEOUS STARS AND STRIPES (S&S) NEWSPAPER AND BUSINESS OPERATIONS Pt. 246, App. E Appendix E to Part 246—Stars and Stripes (S&S) Board of Directors A. Organization and Management...

  4. Mapping of stripe rust resistance gene in an Aegilops caudata ...

    Indian Academy of Sciences (India)

    ... rust resistance depicted a single major gene conditioning adult plant resistance (APR) with stripe rust reaction varying from TR-20MS in resistant RILs signifying the presence of some minor genes as well. Genetic association with leaf rust resistance revealed that two genes are located at a recombination distance of 13%.

  5. Anatomical studies of the gastrointestinal tract of the striped sand ...

    African Journals Online (AJOL)

    A study was carried out on the gross anatomical, morphometric features and histology of the gastrointestinal tract of the Striped Sand Snake (Psammophis sibilans). Ten snakes (five males and five females) were euthanized and dissected for the study. The gastrointestinal tract appeared as a straight tubular organ from oral ...

  6. Distribution patterns of striped mullet Mugil cephalus in mangrove ...

    African Journals Online (AJOL)

    Spatial and seasonal variations in density of striped mullet Mugil cephalus were investigated in four mangrove creeks in Zanzibar, Tanzania, during a one-year cycle. Fish were collected monthly in the lower, intermediate and upper reaches of each creek using a beach-seine net. All fish collected were juveniles between 2 ...

  7. Mapping of stripe rust resistance gene in an Aegilops caudata ...

    Indian Academy of Sciences (India)

    Artificial rust epidemic was created by spraying the infector rows and experimental material with the mixture of uredinospores of Pst isolates 78S84 and 46S119. Stripe rust assessment was according to the modified Cobb's scale. (Peterson et al. 1948). The RIL population was screened at the seedling stage against leaf rust ...

  8. Monitoring quantity and quality of striped catfish pond effluent

    NARCIS (Netherlands)

    Heijden, van der P.G.M.; Poelman, M.; Bosma, R.H.; Long, N.; Son, V.M.

    2012-01-01

    The production of striped catfish and other fish species in ponds has several possible impacts on the environment, one of which is caused by the discharge of pond waste water (effluent), which is enriched with nitrogen and phosphorous compounds as result of feeding and fish faeces. To restrict the

  9. Intervertebral Disk Disease in 3 Striped Skunks (Mephitis mephitis)

    NARCIS (Netherlands)

    Krauss, M.W.; Benato, L.; McDonnell, J.; Schoemaker, N.J.; Westerhof, I.; Bronson, E.; Gielen, I.; van Caelenberg, A.; Hellebuyck, T.; Meij, B.P.; de Decker, S.

    Objective To describe diagnostic findings, surgical technique, and outcome in 3 striped skunks (Mephitis mephitis) with a history of paraparesis. Study Design Case series. Animals Skunks (n = 3) with paraparesis. Methods Neurologic examination revealed upper motor neuron disease (T2–L2) in 2 skunks

  10. Modulation of the innate immune responses in the striped ...

    African Journals Online (AJOL)

    Thus, most of the innate non-specific immune responses are inducible though they are constitutive of fish immune system exhibiting a basal level of activity even in the absence of pathogen challenge. Keywords: Aeromonas hydrophila, Experimental challenge, Innate immune response, Striped snakehead murrel ...

  11. Siim Nestor soovitab : Supreme 7aastane. White Stripes / Siim Nestor

    Index Scriptorium Estoniae

    Nestor, Siim, 1974-

    2005-01-01

    Kolmik Supreme tähistab oma 7. tegutsemisaastat 24. juunil Von Krahlis, kus toimub ka Krecki debüütalbumi "If You Live" (väljaandjaks ettevõte Umblu) esitlus. Detroidi blues-rock duo White Stripes esitleb oma uut albumit "Get Behind Me Satan" 29. juunil Tallinnas klubis Hollywood

  12. Mapping of stripe rust resistance gene in an Aegilops caudata ...

    Indian Academy of Sciences (India)

    Genetic mapping indicated the introgression of stripe rust resistance gene on wheat chromosome. 5DS in the region carrying leaf rust resistance gene LrAc, but as an independent introgression. Simple sequence repeat (SSR) and sequence-tagged site (STS) markers designed from the survey sequence data of 5DS ...

  13. The complete mitochondrial genome of the critically endangered Vietnamese three-striped box turtle (Testudines: Geoemydidae).

    Science.gov (United States)

    Li, Wei; Zhao, Jian; Shi, Yan; Xiao, Feng-Fang; Zhang, Xin-Cheng; Zhu, Xin-Ping

    2015-01-01

    The complete mitochondrial genome of the Vietnamese three-striped box turtle (Cuora cyclornata) was first determined in this study. It was a circular molecule of 16,594 bp in length, consisting of 37 genes typically found in other vertebrates. The AT content of the overall base composition of the whole mitogenome was 60.39%, while the control region was 70.23%. Two ETAS and 4 CSBs were identified, while a remarkable feature was found in the control region: a large number of (TTATTATA)10 direct tandem repeats followed by (TTATA)n (n=10, 8 and 1), which were spaced into three domains by (TA)n (n=1, 1 and 2). The sequence information could play an important role in the study of phylogenetic relationships in turtles and preservation of genetic resources for helping conservation of the endangered species.

  14. Slinky evolution of domain wall brane cosmology

    Science.gov (United States)

    Kadosh, Avihay; Davidson, Aharon; Pallante, Elisabetta

    2012-12-01

    Invoking an initial symmetry between the time t and some extra spatial dimension y, we discuss a novel scenario where the dynamical formation of the 4 dimensional brane and its cosmological evolution are induced simultaneously by a common t↔y symmetry breaking mechanism. The local maximum of the underlying scalar potential is mapped onto a “watershed” curve in the (t,y) plane; the direction tangent to this curve is identified as the cosmic time, whereas the perpendicular direction serves locally as the extra spatial dimension. Special attention is devoted to the so-called slinky configurations, whose brane cosmology is characterized by a decaying cosmological constant along the watershed curve. Such a slinky solution is first constructed within a simplified case where the watershed is constrained by y=0. The physical requirements for a slinky configuration to generate a realistic model of cosmological evolution are then discussed in a more elaborated framework.

  15. Slinky evolution of domain wall brane cosmology

    NARCIS (Netherlands)

    Kadosh, Avihay; Davidson, Aharon; Pallante, Elisabetta

    2012-01-01

    Invoking an initial symmetry between the time t and some extra spatial dimension y, we discuss a novel scenario where the dynamical formation of the 4 dimensional brane and its cosmological evolution are induced simultaneously by a common t y symmetry breaking mechanism. The local maximum of the

  16. Slinky evolution of domain wall brane cosmology

    OpenAIRE

    Kadosh, Avihay; Davidson, Aharon; Pallante, Elisabetta

    2012-01-01

    Invoking an initial symmetry between the time $ t $ and some extra spatial dimension $ y $, we discuss a novel scenario where the dynamical formation of the 4-dim brane and its cosmological evolution are induced simultaneously by a common $ ty $ symmetry breaking mechanism. The local maximum of the underlying scalar potential is mapped onto a 'watershed' curve in the $ (t,y) $ plane; the direction tangent to this curve is identified as the cosmic time, whereas the perpendicular direction serv...

  17. Leptogenesis with left-right domain walls

    Indian Academy of Sciences (India)

    gauge theories and the standard Big Bang cosmology remains an open problem. The combination B + L of the baryon and lepton numbers is known to be anomalous in the standard model (sM). For T >TEW, the temperature of the electroweak phase transition, the B +L violation becomes unsuppressed [1-3]. Thus any B +L.

  18. Ferroelectric domain continuity over grain boundaries

    DEFF Research Database (Denmark)

    Mantri, Sukriti; Oddershede, Jette; Damjanovic, Dragan

    2017-01-01

    Formation and mobility of domain walls in ferroelectric materials is responsible for many of their electrical and mechanical properties. Domain wall continuity across grain boundaries has been observed since the 1950's and is speculated to affect the grain boundary-domain interactions, thereby...... techniques in manipulating the micro-structure and domain structure to result in desired interactions between neighbouring grains could prove to be beneficial for future polycrystalline ferroelectric materials....

  19. Strain Engineering of Ferroelectric Domains in KxNa1−xNbO3 Epitaxial Layers

    Directory of Open Access Journals (Sweden)

    Jutta Schwarzkopf

    2017-08-01

    Full Text Available The application of lattice strain through epitaxial growth of oxide films on lattice mismatched perovskite-like substrates strongly influences the structural properties of ferroelectric domains and their corresponding piezoelectric behavior. The formation of different ferroelectric phases can be understood by a strain-phase diagram, which is calculated within the framework of the Landau–Ginzburg–Devonshire theory. In this paper, we illustrate the opportunity of ferroelectric domain engineering in the KxNa1−xNbO3 lead-free material system. In particular, the following examples are discussed in detail: (i Different substrates (NdGaO3, SrTiO3, DyScO3, TbScO3, and GdScO3 are used to systematically tune the incorporated epitaxial strain from compressive to tensile. This can be exploited to adjust the NaNbO3 thin film surface orientation and, concomitantly, the vector of electrical polarization, which rotates from mainly vertical to exclusive in-plane orientation. (ii In ferroelectric NaNbO3, thin films grown on rare-earth scandate substrates, highly regular stripe domain patterns are observed. By using different film thicknesses, these can be tailored with regard to domain periodicity and vertical polarization component. (iii A featured potassium concentration of x = 0.9 of KxNa1−xNbO3 thin films grown on (110 NdScO3 substrates favors the coexistence of two equivalent, monoclinic, but differently oriented ferroelectric phases. A complicated herringbone domain pattern is experimentally observed which consists of alternating MC and a1a2 domains. The coexistence of different types of ferroelectric domains leads to polarization discontinuities at the domain walls, potentially enabling high piezoelectric responses. In each of these examples, the experimental results are in excellent agreement with predictions based on the linear elasticity theory.

  20. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how walls...

  1. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how walls...... have encouraged architectural thinking of enclosure, materiality, construction and inhabitation in architectural history, the paper’s aim is to define new directions for the integration of LEDs in walls, challenging the thinking of inhabitation and program. This paper introduces the notion...... of “ambiguous walls” as a more “critical” approach to design [1]. The concept of ambiguous walls refers to the diffuse status a lumious and possibly responsive wall will have. Instead of confining it can open up. Instead of having a static appearance, it becomes a context over time. Instead of being hard...

  2. Computer code system for the R and D of nuclear fuel cycle with fast reactor. 2. Development and application of analytical evaluation system for thermal striping phenomena

    International Nuclear Information System (INIS)

    Muramatsu, Toshiharu

    2001-01-01

    Fluid-structure thermal interaction phenomena characterized by stationary random temperature fluctuations, namely thermal striping are observed in the downstream region such as a T-junction piping system of liquid metal fast reactors (LMFRs). Therefore, the piping wall located in the downstream region must be protected against the stationary random thermal process, which might induce high-cycle fatigue. This paper describes the evaluation system based on numerical simulation methods consisting of three thermohydraulics computer programs AQUA, DINUS-3 and THEMIS and of three thermomechanical computer programs BEMSET, FINAS and CANIS, for the thermal striping developed at Japan Nuclear Cycle Development Institute (JNC). Verification results for each computer code and the system are also introduced based on out-of-pile experimental data using water and sodium as working fluids. (author)

  3. Experimental study on thermal-hydraulic for thermal striping phenomena. Results of temperature and velocity measurement among parallel triple jets

    International Nuclear Information System (INIS)

    Miyakoshi, Hiroyuki; Kimura, Nobuyuki; Kamide, Hideki; Miyake, Yasuhiro

    2003-03-01

    A quantitative evaluation on thermal striping, in which temperature fluctuation due to convective mixing among jets causes thermal fatigue in structural components, is of importance for structural integrity and also reactor safety. The treasonable and safety design could be approved by taking account of decay of temperature fluctuation in fluid, during heat transfer from fluid to structure surface and thermal conduction in the structure. In this study, water experiment was performed for vertical and parallel triple jets along wall, those are cold jet in the center and hot jets on both sides. The local temperature and velocity were measured by movable thermocouples and particle image velocimetry (PIV). The both hot jets flowed leaning to the cold jet. The lean of the jets increased as the jets approached the wall. So the convective mixing region among the jets was shifted upstream near the wall. Temperature fluctuation intensity was dependent of the distance from the wall. Under isovelocity condition, prominent frequency component was observed in the power spectrum density of the temperature fluctuation at the furthest position from the wall. The power at the prominent component decreased as the jets approached the wall. Under non-isovelocity condition, on the other hand, the power spectrum density of temperature fluctuation was independent of the distance from the wall. Comparison of the second moment between of velocity PIV and laser Doppler velocimetry showed that the PIV system had high measurement accuracy. Under non-isovelocity condition, the normal components in the second-order moments of fluctuation were smaller than those under isovelocity condition. Normal components in the second-order moments in turbulence was dependent of the distance from the wall. (author)

  4. Domain shape instabilities and dendrite domain growth in uniaxial ferroelectrics

    Science.gov (United States)

    Shur, Vladimir Ya.; Akhmatkhanov, Andrey R.

    2018-01-01

    The effects of domain wall shape instabilities and the formation of nanodomains in front of moving walls obtained in various uniaxial ferroelectrics are discussed. Special attention is paid to the formation of self-assembled nanoscale and dendrite domain structures under highly non-equilibrium switching conditions. All obtained results are considered in the framework of the unified kinetic approach to domain structure evolution based on the analogy with first-order phase transformation. This article is part of the theme issue `From atomistic interfaces to dendritic patterns'.

  5. TaLHY, a 1R-MYB Transcription Factor, Plays an Important Role in Disease Resistance against Stripe Rust Fungus and Ear Heading in Wheat.

    Science.gov (United States)

    Zhang, Zijin; Chen, Jieming; Su, Yongying; Liu, Hanmei; Chen, Yanger; Luo, Peigao; Du, Xiaogang; Wang, Dan; Zhang, Huaiyu

    2015-01-01

    LHY (late elongated hypocotyl) is an important gene that regulates and controls biological rhythms in plants. Additionally, LHY is highly expressed in the SSH (suppression subtractive hybridization) cDNA library-induced stripe rust pathogen (CYR32) in our previous research. To identify the function of the LHY gene in disease resistance against stripe rust, we used RACE-PCR technology to clone TaLHY in the wheat variety Chuannong19. The cDNA of TaLHY is 3085 bp long with an open reading frame of 1947 bp. TaLHY is speculated to encode a 70.3 kDa protein of 648 amino acids , which has one typical plant MYB-DNA binding domain; additionally, phylogenetic tree shows that TaLHY has the highest homology with LHY of Brachypodium distachyon(BdLHY-like). Quantitative fluorescence PCR indicates that TaLHY has higher expression in the leaf, ear and stem of wheat but lower expression in the root. Infestation of CYR32 can result in up-regulated expression of TaLHY, peaking at 72 h. Using VIGS (virus-induced gene silencing) technology to disease-resistant wheat in the fourth leaf stage, plants with silenced TaLHY cannot complete their heading stage. Through the compatible interaction with the stripe rust physiological race CYR32, Chuannong 19 loses its immune capability toward the stripe rust pathogen, indicating that TaLHY may regulate and participate in the heading of wheat, as well as the defense responses against stripe rust infection.

  6. TaLHY, a 1R-MYB Transcription Factor, Plays an Important Role in Disease Resistance against Stripe Rust Fungus and Ear Heading in Wheat.

    Directory of Open Access Journals (Sweden)

    Zijin Zhang

    Full Text Available LHY (late elongated hypocotyl is an important gene that regulates and controls biological rhythms in plants. Additionally, LHY is highly expressed in the SSH (suppression subtractive hybridization cDNA library-induced stripe rust pathogen (CYR32 in our previous research. To identify the function of the LHY gene in disease resistance against stripe rust, we used RACE-PCR technology to clone TaLHY in the wheat variety Chuannong19. The cDNA of TaLHY is 3085 bp long with an open reading frame of 1947 bp. TaLHY is speculated to encode a 70.3 kDa protein of 648 amino acids , which has one typical plant MYB-DNA binding domain; additionally, phylogenetic tree shows that TaLHY has the highest homology with LHY of Brachypodium distachyon(BdLHY-like. Quantitative fluorescence PCR indicates that TaLHY has higher expression in the leaf, ear and stem of wheat but lower expression in the root. Infestation of CYR32 can result in up-regulated expression of TaLHY, peaking at 72 h. Using VIGS (virus-induced gene silencing technology to disease-resistant wheat in the fourth leaf stage, plants with silenced TaLHY cannot complete their heading stage. Through the compatible interaction with the stripe rust physiological race CYR32, Chuannong 19 loses its immune capability toward the stripe rust pathogen, indicating that TaLHY may regulate and participate in the heading of wheat, as well as the defense responses against stripe rust infection.

  7. Striped bass stocks and concentrations of polychlorinated biphenyls

    Science.gov (United States)

    Fabrizio, Mary C.; Sloan, Ronald J.; O'Brien, John F.

    1991-01-01

    Harvest restrictions on striped bass Morone saxatilis fisheries in Atlantic coastal states were relaxed in 1990, but consistent, coastwide regulations of the harvest have been difficult to implement because of the mixed-stock nature of the fisheries and the recognized contamination of Hudson River fish by polychlorinated biphenyls (PCBs). We examined PCB concentrations and stock of origin of coastal striped bass to better understand the effects of these two factors on the composition of the harvest. The probability of observing differences in PCB concentration among fish from the Hudson River stock and the 'southern' group (Chesapeake Bay and Roanoke River stocks combined) was investigated with the logit model (a linear model for analysis of categorical data). Although total PCB concentrations were highly variable among fish from the two groups, striped bass classified as Hudson River stock had a significantly greater probability of having PCB concentrations equal to or greater than 2.00 mg/kg than did fish belonging to the southern group for all age- and size-classes examined. There was a significantly greater probability of observing total PCB concentrations equal to or exceeding 2.00 mg/kg in fish that were 5, 6, and 7 or more years old, and this probability increased linearly with age. We observed similar results when we examined the effect of size on total PCB concentration. The minimum-size limit estimated to permit escapement of fish to sustain stock production is 610 mm total length. Unless total PCB concentrations decrease in striped bass, it is likely that many harvestable fish will have concentrations that exceed the tolerance limit set by the U.S. Food and Drug Administration.

  8. Dynamics of strings between walls

    International Nuclear Information System (INIS)

    Eto, Minoru; Fujimori, Toshiaki; Nagashima, Takayuki; Nitta, Muneto; Ohashi, Keisuke; Sakai, Norisuke

    2009-01-01

    Configurations of vortex strings stretched between or ending on domain walls were previously found to be 1/4 Bogomol'nyi-Prasad-Sommerfield (BPS) states in N=2 supersymmetric gauge theories in 3+1 dimensions. Among zero modes of string positions, the center of mass of strings in each region between two adjacent domain walls is shown to be non-normalizable whereas the rests are normalizable. We study dynamics of vortex strings stretched between separated domain walls by using two methods, the moduli space (geodesic) approximation of full 1/4 BPS states and the charged particle approximation for string end points in the wall effective action. In the first method we explicitly obtain the effective Lagrangian in the strong coupling limit, which is written in terms of hypergeometric functions, and find the 90 deg. scattering for head-on collision. In the second method the domain wall effective action is assumed to be U(1) N gauge theory, and we find a good agreement between two methods for well-separated strings.

  9. Disorder induced stripes in d-wave superconductors

    Science.gov (United States)

    Schmid, Markus; Loder, Florian; Kampf, Arno P.; Kopp, Thilo

    2013-07-01

    Stripe phases are observed experimentally in several copper-based high-Tc superconductors near 1/8 hole doping. However, the specific characteristics may vary depending on the degree of dopant disorder and the presence or absence of a low-temperature tetragonal phase. On the basis of a Hartree-Fock decoupling scheme for the t-J model, we discuss the diverse behavior of stripe phases. In particular, the effect of inhomogeneities is investigated in two distinctly different parameter regimes which are characterized by the strength of the interaction. We observe that small concentrations of impurities or vortices pin the unidirectional density waves, and dopant disorder is capable of stabilizing a stripe phase in parameter regimes where homogeneous phases are typically favored in clean systems. The momentum-space results exhibit universal features for all coexisting density-wave solutions, nearly unchanged even in strongly disordered systems. These coexisting solutions feature generically a full energy gap and a particle-hole asymmetry in the density of states.

  10. Survey of cardiac pathologies in captive striped skunks (Mephitis mephitis).

    Science.gov (United States)

    Benato, Livia; Wack, Allison; Cerveny, Shannon N S; Rosenthal, Steven L; Bronson, Ellen

    2014-06-01

    Cardiac disease is a common finding in small mammals but it is rarely reported in striped skunks (Mephitis mephitis). The aim of this survey was to evaluate the prevalence of cardiac disease in striped skunks and to characterize the types of cardiac disease that might be present. In April 2010, a questionnaire was sent to veterinarians in zoologic collections with membership in the International Species Inventory System. Surveys were distributed to 55 institutions in the United States, Canada, and Europe. Twenty collections with a total of 95 skunks replied to the questionnaire. Of these, five collections reported at least one skunk with cardiac conditions for a total of 11 cases. In these 11 animals, the following conditions were diagnosed: myocardial fibrosis (n = 4), myxomatous valve degeneration (n = 4), hypertrophic cardiomyopathy (n = 1), dilated cardiomyopathy (n = 1), and valvular endocarditis (n = 1). Based on these findings, cardiac diseases should be considered as part of the differential diagnosis in captive striped skunks presenting with weakness, lethargy, and decreased appetite. Cardiac ultrasound also should be considered at the time of annual health examinations to evaluate for possible cardiac conditions at an early stage.

  11. Ultrafast charge localization in a stripe-phase nickelate

    Energy Technology Data Exchange (ETDEWEB)

    Coslovich, Giacomo; Huber, Bernhard; Lee, Wei-Sheng; Sasagawa, Takao; Hussain, Zahid; Bechtel, Hans A.; Martin, Michael C.; Shen, Zhi-Xun; W. Schoenlein, Robert; A. Kaindl, Robert

    2013-08-30

    Self-organized electronically-ordered phases are a recurring feature in correlated materials, resulting in e.g. fluctuating charge stripes whose role in high-Tc superconductivity is under debate. However, the relevant cause-effect relations between real-space charge correlations and low-energy excitations remain hidden in time-averaged studies. Here, we reveal ultrafast charge localization and lattice vibrational coupling as dynamical precursors of stripe formation in the model compound La1.75Sr0.25NiO4, using ultrafast and equilibrium mid-infrared spectroscopy. The opening of a pseudogap at a crossover temperature T* far above long-range stripe formation establishes the onset of electronic localization which is accompanied by an enhanced Fano asymmetry of Ni-O stretch vibrations. Ultrafast excitation triggers a sub-picosecond dynamics exposing the synchronous modulation of electron-phonon coupling and charge localization. These results illuminate the role of localization in forming the pseudogap in nickelates, opening a path to understanding this mysterious phase in a broad class of complex oxides.

  12. NATURAL TRANSVERSE VIBRATIONS OF A PRESTRESSED ORTHOTROPIC PLATE-STRIPE

    Directory of Open Access Journals (Sweden)

    Egorychev Oleg Aleksandrovich

    2012-10-01

    Full Text Available The article represents a new outlook at the boundary-value problem of natural vibrations of a homogeneous pre-stressed orthotropic plate-stripe. In the paper, the motion equation represents a new approximate hyperbolic equation (rather than a parabolic equation used in the majority of papers covering the same problem describing the vibration of a homogeneous orthotropic plate-stripe. The proposed research is based on newly derived boundary conditions describing the pin-edge, rigid, and elastic (vertical types of fixing, as well as the boundary conditions applicable to the unfixed edge of the plate. The paper contemplates the application of the Laplace transformation and a non-standard representation of a homogeneous differential equation with fixed factors. The article proposes a detailed representation of the problem of natural vibrations of a homogeneous orthotropic plate-stripe if rigidly fixed at opposite sides; besides, the article also provides frequency equations (no conclusions describing the plate characterized by the following boundary conditions: rigid fixing at one side and pin-edge fixing at the opposite side; pin-edge fixing at one side and free (unfixed other side; rigid fixing at one side and elastic fixing at the other side. The results described in the article may be helpful if applied in the construction sector whenever flat structural elements are considered. Moreover, specialists in solid mechanics and theory of elasticity may benefit from the ideas proposed in the article.

  13. The STRIPES Trial - Support to Rural India's Public Education System

    Science.gov (United States)

    2010-01-01

    Background Performance of primary school students in India lags far below government expectations, and major disparity exists between rural and urban areas. The Naandi Foundation has designed and implemented a programme using community members to deliver after-school academic support for children in over 1,100 schools in five Indian states. Assessments to date suggest that it might have a substantial effect. This trial aims to evaluate the impact of this programme in villages of rural Andhra Pradesh and will compare test scores for children in three arms: a control and two intervention arms. In both intervention arms additional after-school instruction and learning materials will be offered to all eligible children and in one arm girls will also receive an additional 'kit' with a uniform and clothes. Methods/Design The trial is a cluster-randomised controlled trial conducted in conjunction with the CHAMPION trial. In the CHAMPION trial 464 villages were randomised so that half receive health interventions aiming to reduce neonatal mortality. STRIPES will be introduced in those CHAMPION villages which have a public primary school attended by at least 15 students at the time of a baseline test in 2008. 214 villages of the 464 were found to fulfil above criteria, 107 belonging to the control and 107 to the intervention arm of the CHAMPION trial. These latter 107 villages will serve as control villages in the STRIPES trial. A further randomisation will be carried out within the 107 STRIPES intervention villages allocating half to receive an additional kit for girls on the top of the instruction and learning materials. The primary outcome of the trial is a composite maths and language test score. Discussion The study is designed to measure (i) whether the educational intervention affects the exam score of children compared to the control arm, (ii) if the exam scores of girls who receive the additional kit are different from those of girls living in the other STRIPES

  14. Characterization of non-host resistance in broad bean to the wheat stripe rust pathogen

    Directory of Open Access Journals (Sweden)

    Cheng Yulin

    2012-06-01

    Full Text Available Abstract Background Non-host resistance (NHR confers plant species immunity against the majority of microbial pathogens and represents the most robust and durable form of plant resistance in nature. As one of the main genera of rust fungi with economic and biological importance, Puccinia infects almost all cereals but is unable to cause diseases on legumes. Little is known about the mechanism of this kind of effective defense in legumes to these non-host pathogens. Results In this study, the basis of NHR in broad bean (Vicia faba L. against the wheat stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst, was characterized. No visible symptoms were observed on broad bean leaves inoculated with Pst. Microscopic observations showed that successful location of stomata and haustoria formation were significantly reduced in Pst infection of broad bean. Attempted infection induced the formation of papillae, cell wall thickening, production of reactive oxygen species, callose deposition and accumulation of phenolic compounds in plant cell walls. The few Pst haustoria that did form in broad bean cells were encased in reactive oxygen and callose materials and those cells elicited cell death. Furthermore, a total of seven defense-related genes were identified and found to be up-regulated during the Pst infection. Conclusions The results indicate that NHR in broad bean against Pst results from a continuum of layered defenses, including basic incompatibility, structural and chemical strengthening of cell wall, posthaustorial hypersensitive response and induction of several defense-related genes, demonstrating the multi-layered feature of NHR. This work also provides useful information for further determination of resistance mechanisms in broad bean to rust fungi, especially the adapted important broad bean rust pathogen, Uromyces viciae-fabae, because of strong similarity and association between NHR of plants to unadapted pathogens and basal

  15. Microwave permeability of stripe patterned FeCoN thin film

    International Nuclear Information System (INIS)

    Wu, Yuping; Yang, Yong; Ma, Fusheng; Zong, Baoyu; Yang, Zhihong; Ding, Jun

    2017-01-01

    Magnetic stripe patterns are of great importance for microwave applications owing to their highly tunable microwave permeability by adjusting the geometrical dimensions. In this work, stripe patterned FeCoN films with 160 nm thickness are fabricated by using standard UV photolithography. Their microwave permeability are investigated systematically via both experiment and micromagnetic simulation. The good agreement between experimental and simulation results suggests that stripe width is crucial for the microwave magnetic properties of the stripe pattern. It is demonstrated by simulation that with increasing stripe width from 1 to 80 µm the initial permeability shows a continuous growth from about 8–322, whiles the resonance frequency drops dramatically from 18.7 to 3.1 GHz at 4 µm gap size. Smaller gap size would result in slightly increased initial permeability due to larger magnetic volume ratio, accompanied by decreased resonance frequency because of stronger magnetostatic interaction. Moreover, the experimental investigation on stripe length effect indicates that the stripe length should be kept as long as possible to achieve uniform bulk resonance mode and high permeability value. Insufficient stripe length would result in low frequency edge mode and decayed bulk mode. This study could provide valuable guidelines on the selection of proper geometry dimensions of FeCoN stripe patterns for high frequency applications. - Highlights: • This work presents a systematic study on permeability of FeCoN stripe pattern. • Geometrical parameters of the stripe pattern are systematically optimized. • Several important conclusions has been obtained. • The results offer guideline on FeCoN stripe patterns for high frequency applications.

  16. Microwave permeability of stripe patterned FeCoN thin film

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yuping [Temasek Laboratories, National University of Singapore, 5A Engineering Drive 1, Singapore 117411 (Singapore); Yang, Yong, E-mail: tslyayo@nus.edu.sg [Temasek Laboratories, National University of Singapore, 5A Engineering Drive 1, Singapore 117411 (Singapore); Ma, Fusheng; Zong, Baoyu; Yang, Zhihong [Temasek Laboratories, National University of Singapore, 5A Engineering Drive 1, Singapore 117411 (Singapore); Ding, Jun [Department of Materials Science and Engineering, National University of Singapore, Singapore 117574 (Singapore)

    2017-03-15

    Magnetic stripe patterns are of great importance for microwave applications owing to their highly tunable microwave permeability by adjusting the geometrical dimensions. In this work, stripe patterned FeCoN films with 160 nm thickness are fabricated by using standard UV photolithography. Their microwave permeability are investigated systematically via both experiment and micromagnetic simulation. The good agreement between experimental and simulation results suggests that stripe width is crucial for the microwave magnetic properties of the stripe pattern. It is demonstrated by simulation that with increasing stripe width from 1 to 80 µm the initial permeability shows a continuous growth from about 8–322, whiles the resonance frequency drops dramatically from 18.7 to 3.1 GHz at 4 µm gap size. Smaller gap size would result in slightly increased initial permeability due to larger magnetic volume ratio, accompanied by decreased resonance frequency because of stronger magnetostatic interaction. Moreover, the experimental investigation on stripe length effect indicates that the stripe length should be kept as long as possible to achieve uniform bulk resonance mode and high permeability value. Insufficient stripe length would result in low frequency edge mode and decayed bulk mode. This study could provide valuable guidelines on the selection of proper geometry dimensions of FeCoN stripe patterns for high frequency applications. - Highlights: • This work presents a systematic study on permeability of FeCoN stripe pattern. • Geometrical parameters of the stripe pattern are systematically optimized. • Several important conclusions has been obtained. • The results offer guideline on FeCoN stripe patterns for high frequency applications.

  17. A Content Analysis Comparison between Stars and Stripes and Commercial National Newspapers

    Science.gov (United States)

    1990-01-01

    McQuail , Mass Communication Theory , (London: Sage Publications, 1983) 126. 15 He notes that some of the concerns... Communication Theory . London: SAGE Publications, 1983. " S & S Ombudsman’E Plan Draws Fire," European Stars and Stripes, 4 February 1990. "Stars and Stripes May...STRIPES AND COMMERCIAL NATIONAL NEWSPAPERS A THESIS APPROVED FOR THE DEPARTMENT OF JOURNALISM AND MASS COMMUNICATION By Shirley Rafey Bruce Hinson

  18. Relationship of Soil Properties and Sugarcane Yields to Red Stripe in Louisiana.

    Science.gov (United States)

    Johnson, Richard M; Grisham, Michael P; Warnke, Kathryn Z; Maggio, Jeri R

    2016-07-01

    Symptoms of red stripe disease caused by Acidovorax avenae subsp. avenae in Louisiana between 1985 and 2010 were limited to the leaf stripe form, which caused no apparent yield loss. During 2010, the more severe top rot form was observed, and a study was initiated to investigate the distribution of red stripe in the field and determine its effects on cane and sugar yields. Soil properties data, red stripe incidence, and sugarcane yields were all highly variable and were not randomly distributed in the field. Combined harvest data showed a negative correlation between yield components and red stripe incidence, with the strongest relationship between sucrose per metric ton and disease incidence. Red stripe incidence was positively correlated with several soil properties, including phosphorus, potassium, zinc, and calcium. Red stripe incidence also was found to increase with increasing nitrogen rate, with the greatest effects in heavy soils. Results also indicated that using red-stripe-infected cane as a seed source can significantly decrease shoot emergence, stalk population, and subsequent cane and sugar yields. These combined data suggest that red stripe disease can exhibit a highly variable rate of infection in commercial sugarcane fields and may also significantly decrease sugar yields.

  19. Microsatellite markers linked to the locus of the watermelon fruit stripe pattern.

    Science.gov (United States)

    Gama, R N C S; Santos, C A F; Dias, R C S; Alves, J C S F; Nogueira, T O

    2015-01-16

    Agronomic performance and external and internal appearance of watermelon (Citrullus lanatus) fruit are important traits that should be taken into consideration during the development of a new cultivar, as well as being the principal identification elements used by the consumer, which are based on the external appearance and quality of the fruit. Externally, the fruit can be characterized in terms of the shape, the color of the lower rind, and the presence of grooves and stripes, the stripes can be classified as clearly defined or diffuse. The objective of this study was to identify microsatellite markers linked to the stripe pattern of watermelon fruit to support watermelon improvement programs, with the selection of this characteristic in the plantlet stage. F1 and F2 populations, result of a cross between the cultivars BRS Opara (clearly defined stripes) and Pérola (diffuse stripes), were phenotyped for their fruit stripe pattern. The CTAB 2X protocol was used for DNA extraction and 116 microsatellite markers were examined in a group of F2 plants that had fruit with well-defined stripes and fruit with diffuse stripes. The microsatellite loci MCPI_05 and MCPI_16 exhibited a linkage to the stripe pattern at a distance of 1.5 and 1.8 cM, respectively, with LOD scores of 39.28 and 38.11, respectively, which were located on chromosome six of the watermelon genome. These markers can be used in marker-assisted selection in watermelon improvement programs, by various research institutions.

  20. Physical Localization of a Locus from Agropyron cristatum Conferring Resistance to Stripe Rust in Common Wheat.

    Science.gov (United States)

    Zhang, Zhi; Song, Liqiang; Han, Haiming; Zhou, Shenghui; Zhang, Jinpeng; Yang, Xinming; Li, Xiuquan; Liu, Weihua; Li, Lihui

    2017-11-13

    Stripe rust, caused by Puccinia striiformis f. sp. tritici ( Pst ), is one of the most destructive diseases of wheat ( Triticum aestivum L.) worldwide. Agropyron cristatum (L.) Gaertn. (2 n = 28, PPPP), one of the wild relatives of wheat, exhibits resistance to stripe rust. In this study, wheat- A . cristatum 6P disomic addition line 4844-12 also exhibited resistance to stripe rust. To identify the stripe rust resistance locus from A . cristatum 6P, ten translocation lines, five deletion lines and the BC₂F₂ and BC₃F₂ populations of two wheat- A . cristatum 6P whole-arm translocation lines were tested with a mixture of two races of Pst in two sites during 2015-2016 and 2016-2017, being genotyped with genomic in situ hybridization (GISH) and molecular markers. The result indicated that the locus conferring stripe rust resistance was located on the terminal 20% of 6P short arm's length. Twenty-nine 6P-specific sequence-tagged-site (STS) markers mapped on the resistance locus have been acquired, which will be helpful for the fine mapping of the stripe rust resistance locus. The stripe rust-resistant translocation lines were found to carry some favorable agronomic traits, which could facilitate their use in wheat improvement. Collectively, the stripe rust resistance locus from A . cristatum 6P could be a novel resistance source and the screened stripe rust-resistant materials will be valuable for wheat disease breeding.

  1. WE-EF-207-10: Striped Ratio Grids: A New Concept for Scatter Estimation

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, S [Stanford University, Stanford, CA (United States)

    2015-06-15

    Purpose: To propose a new method for estimating scatter in x-ray imaging. We propose the “striped ratio grid,” an anti-scatter grid with alternating stripes of high scatter rejection (attained, for example, by high grid ratio) and low scatter rejection. To minimize artifacts, stripes are oriented parallel to the direction of the ramp filter. Signal discontinuities at the boundaries between stripes provide information on local scatter content, although these discontinuities are contaminated by variation in primary radiation. Methods: We emulated a striped ratio grid by imaging phantoms with two sequential CT scans, one with and one without a conventional grid, and processed them together to mimic a striped ratio grid. Two phantoms were scanned with the emulated striped ratio grid and compared with a conventional anti-scatter grid and a fan-beam acquisition, which served as ground truth. A nonlinear image processing algorithm was developed to mitigate the problem of primary variation. Results: The emulated striped ratio grid reduced scatter more effectively than the conventional grid alone. Contrast is thereby improved in projection imaging. In CT imaging, cupping is markedly reduced. Artifacts introduced by the striped ratio grid appear to be minimal. Conclusion: Striped ratio grids could be a simple and effective evolution of conventional anti-scatter grids. Unlike several other approaches currently under investigation for scatter management, striped ratio grids require minimal computation, little new hardware (at least for systems which already use removable grids) and impose few assumptions on the nature of the object being scanned.

  2. Bi-sensory, striped representations: comparative insights from owl and platypus.

    Science.gov (United States)

    Pettigrew, John D

    2004-01-01

    Bi-sensory striped arrays are described in owl and platypus that share some similarities with the other variant of bi-sensory striped array found in primate and carnivore striate cortex: ocular dominance columns. Like ocular dominance columns, the owl and platypus striped systems each involve two different topographic arrays that are cut into parallel stripes, and interdigitated, so that higher-order neurons can integrate across both arrays. Unlike ocular dominance stripes, which have a separate array for each eye, the striped array in the middle third of the owl tectum has a separate array for each cerebral hemisphere. Binocular neurons send outputs from both hemispheres to the striped array where they are segregated into parallel stripes according to hemisphere of origin. In platypus primary somatosensory cortex (S1), the two arrays of interdigitated stripes are derived from separate sensory systems in the bill, 40,000 electroreceptors and 60,000 mechanoreceptors. The stripes in platypus S1 cortex produce bimodal electrosensory-mechanosensory neurons with specificity for the time-of-arrival difference between the two systems. This "thunder-and-lightning" system would allow the platypus to estimate the distance of the prey using time disparities generated at the bill between the earlier electrical wave and the later mechanical wave caused by the motion of benthic prey. The functional significance of parallel, striped arrays is not clear, even for the highly-studied ocular dominance system, but a general strategy is proposed here that is based on the detection of temporal disparities between the two arrays that can be used to estimate distance.

  3. Spatial distribution of Prosopis glandulosa var. torreyana in vegetation stripes of the southern Chihuahuan Desert

    Science.gov (United States)

    López-Portillo, Jorge; Montaña, Carlos

    1999-05-01

    Mosaics consisting of vegetation stripes surrounded by bare areas have been described in several arid and semiarid ecosystems. The dynamics of the system depends on the redistribution of rainwater which is preferentially stored and evapotranspired in the vegetated stripes. A process of plant `colonization' in the upslope fringe of the stripes has been described in some cases and a consequent upslope migration of the stripes has been inferred, but not confirmed in all cases quoted in the literature. In this paper, we studied the spatial distribution of mesquite ( Prosopis glandulosa var. torreyana) and the soil parameters in three vegetation stripes and their associated bare areas in the southern Chihuahuan Desert. The spatial distribution of mesquites of different sizes do not coincide with that expected under the hypothesis of an uniform upslope stripe migration, but soil data suggest that current bare areas had been vegetated some time ago. Dispersion and establishment abilities enhanced by overgrazing may explain the observed mesquite distribution, but the presence of trees with high basal diameters in any part of the stripes suggests stripe permanence at the same site and no upslope migration. These results point to the conflicting evidence on stripe migration that has been already found in other areas. The most probable scenario in our study area is that of a general long-term change of form of the stripes taking place at very variable speeds in different stripes, including the possibility that some of them remain stationary for prolonged periods, and showing different histories of colonization according to the life-history of the different species concerned. The speed and regularity of the process would show a very high temporal and spatial variability due to the interaction of climatic, geomorphologic and biotic interactions.

  4. Assessing Fishers' Support of Striped Bass Management Strategies.

    Science.gov (United States)

    Murphy, Robert D; Scyphers, Steven B; Grabowski, Jonathan H

    2015-01-01

    Incorporating the perspectives and insights of stakeholders is an essential component of ecosystem-based fisheries management, such that policy strategies should account for the diverse interests of various groups of anglers to enhance their efficacy. Here we assessed fishing stakeholders' perceptions on the management of Atlantic striped bass (Morone saxatilis) and receptiveness to potential future regulations using an online survey of recreational and commercial fishers in Massachusetts and Connecticut (USA). Our results indicate that most fishers harbored adequate to positive perceptions of current striped bass management policies when asked to grade their state's management regime. Yet, subtle differences in perceptions existed between recreational and commercial fishers, as well as across individuals with differing levels of fishing experience, resource dependency, and tournament participation. Recreational fishers in both states were generally supportive or neutral towards potential management actions including slot limits (71%) and mandated circle hooks to reduce mortality of released fish (74%), but less supportive of reduced recreational bag limits (51%). Although commercial anglers were typically less supportive of management changes than their recreational counterparts, the majority were still supportive of slot limits (54%) and mandated use of circle hooks (56%). Our study suggests that both recreational and commercial fishers are generally supportive of additional management strategies aimed at sustaining healthy striped bass populations and agree on a variety of strategies. However, both stakeholder groups were less supportive of harvest reductions, which is the most direct measure of reducing mortality available to fisheries managers. By revealing factors that influence stakeholders' support or willingness to comply with management strategies, studies such as ours can help managers identify potential stakeholder support for or conflicts that may

  5. MEDIASTINAL LYMPHOMA AND CHYLOTHORAX IN A STRIPED SKUNK (MEPHITIS MEPHITIS).

    Science.gov (United States)

    Liptovszky, Mátyás; Kerekes, Zoltán; Perge, Edina; Vajdovich, Péter; Papp, Endre Ákos; Molnár, Viktor

    2017-06-01

    Tumors are infrequently reported in skunks, with only a few case reports published in the literature. Chylothorax associated with mediastinal lymphoma was diagnosed in a captive 7-yr-old male striped skunk ( Mephitis mephitis ). The animal presented with anorexia and apathy. Supportive care and prednisolone improved the animal's clinical status for 2 wk preceding its death. Histopathology supported the clinical findings, and the tumor was classified as a mediastinal non-Hodgkin lymphoma, stage 2b, which has not been documented in the literature.

  6. Behavior and Body Patterns of the Larger Pacific Striped Octopus.

    Directory of Open Access Journals (Sweden)

    Roy L Caldwell

    Full Text Available Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012-2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown.

  7. Behavior and Body Patterns of the Larger Pacific Striped Octopus.

    Science.gov (United States)

    Caldwell, Roy L; Ross, Richard; Rodaniche, Arcadio; Huffard, Christine L

    2015-01-01

    Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012-2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown.

  8. Domain Selectivity in BiFeO3 Thin Films by Modified Substrate Termination

    NARCIS (Netherlands)

    Solmaz, Alim; Huijben, Mark; Koster, Gertjan; Egoavil, Ricardo; Gauquelin, Nicolas; Van Tendeloo, Gustaaf; Verbeeck, Jo; Noheda, Beatriz; Rijnders, Guus

    2016-01-01

    Ferroelectric domain formation is an essential feature in ferroelectric thin films. These domains and domain walls can be manipulated depending on the growth conditions. In rhombohedral BiFeO3 thin films, the ordering of the domains and the presence of specific types of domain walls play a crucial

  9. THz reflectometric imaging of medieval wall paintings

    DEFF Research Database (Denmark)

    Dandolo, Corinna Ludovica Koch; Jepsen, Peter Uhd

    2013-01-01

    Terahertz time-domain reflectometry has been applied to the investigation of a medieval Danish wall painting. The technique has been able to detect the presence of carbonblack layer on the surface of the wall painting and a buried insertion characterized by high reflectivity values has been found...

  10. CLIMBING WALL

    CERN Multimedia

    1999-01-01

    The FIRE AND RESCUE Group of TIS Commission informs that the climbing wall in the yard of the Fire-fighters Station, is intended for the sole use of the members of that service, and recalls that access to this installation is forbidden for safety reasons to all persons not belonging to the Service.CERN accepts no liability for damage or injury suffered as a result of failure to comply with this interdiction.TIS/DI

  11. Assessing the variability of Red Stripe Disease in Louisiana sugarcane using precision agriculture methods

    Science.gov (United States)

    Symptoms of red stripe disease caused by Acidovorax avenae subsp. avenae in Louisiana between 1985 and 2010 were limited to the leaf stripe form which caused no apparent yield loss. During 2010, the more severe top rot form was observed, and a study was initiated to investigate the distribution of r...

  12. Osmoregulatory effects of hypophysectomy and homologous prolactin replacement in hybrid striped bass

    DEFF Research Database (Denmark)

    Jackson, Leslie F; McCormick, Stephen D; Madsen, Steffen S

    2005-01-01

    The effects of ovine prolactin (oPRL) and striped bass prolactin (sbPRL; Morone saxatilis) on plasma osmolality, electrolyte balance, and gill Na+,K+-ATPase activity were investigated in hypophysectomized (Hx), freshwater (FW)-acclimated, hybrid striped bass (M. saxatilis x Morone chrysops...

  13. Color Fringes Bordering Black Stripes at the Bottom of a Swimming Pool

    Science.gov (United States)

    Fuster, Gonzalo; Rojas, Roberto; Slüsarenko, Viktor

    2016-01-01

    We have observed a nice example of chromatic dispersion due to refraction in water, in the form of color fringes bordering the black stripes that exist at the bottom of a swimming pool. Here we give a qualitative description of the phenomenon, explaining the role of the black stripes and the dispersive index of refraction of water.

  14. Genetics of leaf and stripe rust resistance in a bread wheat cultivar ...

    Indian Academy of Sciences (India)

    MYT), Mexico, has shown resistance to leaf rust and stripe rust in the Indian ... rust resistance against. -isogenic line genes present Leaf rust. Stripe rust. Origin. Source. Parentage. Tonichi. –. TR. 10.0. Mexico. RAMC CAR422/Anahuac75. CSP44. Lr48 .... separately have been reported earlier by several authors. Table 2.

  15. Genetics of adult plant stripe rust resistance in CSP44, a selection ...

    Indian Academy of Sciences (India)

    This suggests the presence of nonhypersensitive adult plant stripe rust resistance in the line CSP44. The evaluation of F1, F2 and F3 generations and F6 SSD families from the cross of CSP44 with susceptible wheat cultivar WL711 for stripe rust severity indicated that the resistance in CSP44 is based on two genes showing ...

  16. Genetics of adult plant stripe rust resistance in CSP44, a selection ...

    Indian Academy of Sciences (India)

    Unknown

    Wheat line CSP44, a selection from an Australian bread wheat cultivar Condor, has shown resistance to stripe rust in. India since the last twenty years. Seedlings and adult plants of CSP44 showed susceptible infection types against stripe rust race 46S119 but displayed average terminal disease severity of 2.67 on adult ...

  17. Comparisons of egg quality traits, egg weight loss and hatchability between striped and normal duck eggs.

    Science.gov (United States)

    Yuan, J; Wang, B; Huang, Z; Fan, Y; Huang, C; Hou, Z

    2013-01-01

    1. The egg quality of striped and normal duck eggs was compared to determine why striped eggs show decreased hatchability. A total of 430 eggs, obtained from a Pekin duck breeder flock aged 50-65 wks, were used in three experiments. The eggs were weighed and assigned randomly to measure egg quality traits, egg weight (EW) loss and hatchability during incubation. 2. There were no significant differences between egg types in terms of egg shape index, eggshell strength and thickness, albumen height, Haugh unit, yolk colour, weight of the eggshell with or without membranes, calcium, phosphorus, copper and manganese contents in the eggshell (with the inner and outer membranes or without the inner membrane), albumen weight, dry matter of albumen, crude protein (CP) of thick albumen and pH of the thick albumen. 3. The weight of eggshells with membranes, weight of thick albumen and CP of thin albumen in striped eggs were lower than those in normal eggs. 4. The thin albumen in striped eggs was heavier than that in normal eggs. The pH of the thin albumin in striped egg was significantly higher than that in normal eggs. 5. There were no significant differences in EW loss during incubation or duckling weight between striped and normal eggs. However, the hatchability of striped eggs was lower. 6. The lower weight of the eggshell inner membrane and thick albumen, lower CP content and higher pH in the thin albumen of striped eggs might contribute to lower hatchability.

  18. Mapping genes for resistance to stripe rust in spring wheat landrace PI 480035

    Science.gov (United States)

    Stripe rust caused by Puccinia striiformis Westend. f. sp. tritici Erikks. is an economically important disease of wheat (Triticum aestivum L.). Hexaploid spring wheat landrace PI 480035 was highly resistant to stripe rust in the field in Washington during 2011 and 2012. The objective of this resear...

  19. Influence of single-walled carbon nanotubes (< 0.001 wt %) and/or zwitter-ionic phospholipid (SOPC) surface layer on the behaviour of the gradient flexoelectric and surface induced polarization domains arising in a homeotropic E7 (a mixture of 5CB, 7CB, 8OCB and 5CT) nematic layer

    International Nuclear Information System (INIS)

    Hinov, H P; Pavlic, J I; Marinov, Y G; Petrov, A G; Sridevi, S; Rafailov, P M; Dettlaff-Weglikowska, U

    2010-01-01

    The influence has been studied of single-walled carbon nanotubes with a concentration between 0.0001 and 0.001 wt % and a dried zwitter-ionic phospholipid (SOPC: l-stearoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine) layer of thickness, smaller than 0.5 μm, deposited only on a half of one of the two glass plates, on the behaviour of the gradient flexoelectric and surface polarization induced domains arising in a homeotropic nematic E7 (a mixture of 5CB, 7CB, 8OCB and 5CT) layer. We have observed for the first time different polar on/off formation of the surface polarization induced domains in the region of the liquid crystal cell without surface deposited lipid SOPC layer. On the other hand, the SOPC layer strongly decreases the gradient of the electric field thus leading to less-pronounced flexoelectric domains. However, the SOPC layer does not influence the creation of surface polarization induced domains and of injection induced domains arising at voltages above 4V. Appropriate dynamic light transmitted curves have been recorded and typical microphotographs have been taken.

  20. Mice as stowaways? Colonization history of Danish striped field mice.

    Science.gov (United States)

    Andersen, Liselotte Wesley; Jacobsen, Magnus; Vedel-Smith, Christina; Jensen, Thomas Secher

    2017-07-01

    Species from the steppe region of Eastern Europe likely colonized northwestern Europe in connection with agriculture after 6500 BP. The striped field mouse ( Apodemus agrarius Pallas, 1783), is a steppe-derived species often found in human crops. It is common on the southern Danish islands of Lolland and Falster, which have been isolated from mainland Europe since approximately 10 300-8000 BP. Thus, this species could have been brought in with humans in connection with agriculture, or it could be an earlier natural invader. We sequenced 86 full mitochondrial genomes from the northwestern range of the striped field mouse, analysed phylogenetic relationships and estimated divergence time. The results supported human-induced colonization of Denmark in the Subatlantic or Subboreal period. A newly discovered population from Central Jutland in Denmark diverged from Falster approximately 100-670 years ago, again favouring human introduction. One individual from Sweden turned out to be a recent introduction from Central Jutland. © 2017 The Author(s).

  1. Systemic sarcocystosis in a striped skunk (Mephitis mephitis).

    Science.gov (United States)

    Burcham, G N; Ramos-Vara, J A; Vemulapalli, R

    2010-05-01

    A striped skunk with neurological signs was euthanized and examined via necropsy. Histologically, protozoa were found in multiple tissues. Protozoal schizonts measured 15 to 25 mum in diameter and contained 4 to 6 mum crescent-shaped merozoites. Protozoa were associated with necrosis and inflammation in the lung, brain, liver, and nasal epithelium. Immunohistochemistry labeled protozoa strongly positive for Sarcocystis neurona. Polymerase chain reaction-amplified products from the protozoan were 99.6% identical to the corresponding portion of the nuclear small subunit ribosomal RNA gene of S neurona. S neurona origin was further confirmed by amplifying a 451-base pair DNA fragment from the skunk lung, which differed by just 2 or 3 base pairs from the small subunit ribosomal RNA gene of S neurona. Striped skunks act as intermediate and aberrant hosts for S neurona; however, S neurona has rarely been found in extraneural tissues in any species, and systemic sarcocystosis has not been reported in skunks. Additionally, canine distemper virus infection was confirmed with histopathology and immunohistochemistry. Concurrent canine distemper suggests that immunosuppression may have played a role in S neurona infection in this skunk.

  2. Spatial inhomogeneities in iron pnictide superconductors: The formation of charge stripes

    Science.gov (United States)

    Gor'Kov, Lev P.; Teitel'Baum, Gregory B.

    2010-07-01

    The heterogeneous coexistence of antiferromagnetism [spin-density wave (SDW)] and superconductivity on a mesoscopic scale was observed in iron pnictides in many recent experiments. We suggest and discuss the scenario in which the heterogeneity is caused by formation of domain walls inherent to the SDW state of pnictides at a proper doping or under applied pressure. Superconductivity would emerge from the modulated SDW structure. The phenomenon is akin to the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) phase in superconductors.

  3. Stripe to slab confinement for the linearization of macromolecules in nanochannels.

    Science.gov (United States)

    Benková, Zuzana; Námer, Pavol; Cifra, Peter

    2015-03-21

    We investigated the recently suggested advantageous analysis of chain linearization experiments with macromolecules confined in a stripe-like channel (Huang and Battacharya, EPL, 2014, 106, 18004) using Monte Carlo simulations. The enhanced chain extension in a stripe, which is due to the significant excluded volume interactions between the monomers in two dimensions, weakens considerably on transition to an experimentally feasible slit-like channel. Based on the chain extension-confinement strength dependence and the structure factor behavior for a chain in a stripe, we infer the excluded volume regime (de Gennes regime) typical for two-dimensional systems. On widening of the stripe in a direction perpendicular to the stripe plane, i.e. on the transition to the slab geometry, the advantageous chain extension decreases and a Gaussian regime is observed for not very long semiflexible chains. The evidence for pseudo-ideality in confined chains is based on four indicators: the extension curves, variation of the extension with the persistence length P, estimated limits for the regimes in the investigated systems, and the structure factor behavior. The slab behavior can be observed when the two-dimensional stripe (originally of a one-monomer thickness) reaches a reduced thickness D larger than approximately D/P ≈ 0.2 in the third dimension. This maximum height of a slab at which the advantage of a stripe is retained is very low and has implications for DNA linearization experiments.

  4. Intervertebral disk disease in 3 striped skunks (Mephitis mephitis).

    Science.gov (United States)

    Krauss, Maximiljan W; Benato, Livia; Wack, Allison; McDonnell, John J; Schoemaker, Nico J; Westerhof, Ineke; Bronson, Ellen; Gielen, Ingrid; Van Caelenberg, Annemie; Hellebuyck, Tom; Meij, Björn P; De Decker, Steven

    2014-07-01

    To describe diagnostic findings, surgical technique, and outcome in 3 striped skunks (Mephitis mephitis) with a history of paraparesis. Case series. Skunks (n = 3) with paraparesis. Neurologic examination revealed upper motor neuron disease (T2-L2) in 2 skunks and lower motor neuron disease (L3-S3) in 1 skunk. Diagnostic imaging included radiography, myelography, CT, and MRI and confirmed intervertebral disk herniation (IVDH) in each skunk. Because initial treatment with pain medication and cage rest did not result in lasting improvement, spinal surgery was performed. Hemilaminectomy (2 skunks) and dorsal laminectomy (1 skunk) was performed with removal of extruded disk material. The skunks improved after surgery but all had minor residual neurologic deficits when examined at various times postoperatively. Thoracolumbar intervertebral disk herniation occurs in skunks, and must be included in the differential diagnosis of paraparesis. © Copyright 2014 by The American College of Veterinary Surgeons.

  5. Rogue wave and a pair of resonance stripe solitons to a reduced (3+1)-dimensional Jimbo-Miwa equation

    Science.gov (United States)

    Zhang, Xiaoen; Chen, Yong

    2017-11-01

    In this paper, a combination of stripe soliton and lump soliton is discussed to a reduced (3+1)-dimensional Jimbo-Miwa equation, in which such solution gives rise to two different excitation phenomena: fusion and fission. Particularly, a new combination of positive quadratic functions and hyperbolic functions is considered, and then a novel nonlinear phenomenon is explored. Via this method, a pair of resonance kink stripe solitons and rogue wave is studied. Rogue wave is triggered by the interaction between lump soliton and a pair of resonance kink stripe solitons. It is exciting that rogue wave must be attached to the stripe solitons from its appearing to disappearing. The whole progress is completely symmetry, the rogue wave starts itself from one stripe soliton and lose itself in another stripe soliton. The dynamic properties of the interaction between one stripe soliton and lump soliton, rogue wave are discussed by choosing appropriate parameters.

  6. Static and dynamic magnetic properties of stripe-patterned Fe20Ni80 soft magnetic films

    Science.gov (United States)

    Zhu, Zengtai; Feng, Hongmei; Cheng, Xiaohong; Xie, Hongkang; Liu, Qingfang; Wang, Jianbo

    2018-01-01

    Stripe-patterned soft magnetic Fe20Ni80 films were fabricated on silicon substrate via radio frequency magnetron sputtering technology. The static and dynamic magnetic properties of samples were measured by a vibrating sample magnetometer and vector network analyzer. The vector network analyzer ferromagnetic resonance technique was used to analyze the experimental results, which showed that damping and in-plane uniaxial anisotropy can be tuned significantly for the samples with various stripe widths from 5 to 20 µm. A stripe-shaped anisotropy model was used to analyze the experimental results, which were in accord with the theoretical predictions. Moreover, the variation of damping was investigated in detail.

  7. Striped Bass Spawning in Non-Estuarine Portions of the Savannah River

    Energy Technology Data Exchange (ETDEWEB)

    Martin, D.; Paller, M.

    2007-04-17

    Historically, the estuarine portions of the Savannah River have been considered to be the only portion of the river in which significant amounts of striped bass (Morone saxatilis) spawning normally occur. A reexamination of data from 1983 through 1985 shows a region between River Kilometers 144 and 253 where significant numbers of striped bass eggs and larvae occur with estimated total egg production near that currently produced in the estuarine reaches. It appears possible that there are two separate spawning populations of striped bass in the Savannah River.

  8. Sequence analysis of RNA3 of Maize stripe virus associated with stripe disease of sorghum (Sorghum bicolor in India

    Directory of Open Access Journals (Sweden)

    Kalanghad Puthankalam SRINIVAS

    2014-05-01

    Full Text Available Maize stripe virus (MSpV, one of the distinct species of the genus Tenuivirus, has been associated with stripe disease of sorghum in India. In this study, we report the complete sequence analysis of ambisense RNA3 of four MSpV isolates associated with this disease, to confirm its correct identity. The RNA3 of four MSpV-Sorg isolates is 2357 nucleotides in length with two ORFs, one in virion sense (594 nucleotides, non-structural protein 3, NS3 and the other in complementary sense (951 nucleotides, coat protein, CP. The intergenic region between these two ORFs is 653 nucleotides in length, which is rich in U and A residues. The deduced molecular weights of NS3 and CP are ≈22 and ≈34 kDa, respectively. RNA3 has ≈82% sequence identity at nucleotide level with RNA3 of MSpV infecting maize in Florida, USA and Reunion. NS3 and CP ORFs shared ≈94% and ≈95% identities at amino acid levels, respectively with MSpV isolates of maize from Florida and Reunion. The internal non-coding region between two ORFs has 67–68% identity at nucleotide level with the reported MSpV isolates from Florida and Reunion. The sequence identity was more than ≈98% among the four isolates of MSpV-Sorg. Compared to maize-infecting MSpV isolates in USA and Reunion, the sorghum-infecting MSpV isolates in India had more amino acid substitutions in both NS3 and CP. This is the first report of complete sequence analysis of MSpV RNA3 from Asia.

  9. Falling walls

    CERN Multimedia

    It was 20 years ago this week that the Berlin wall was opened for the first time since its construction began in 1961. Although the signs of a thaw had been in the air for some time, few predicted the speed of the change that would ensue. As members of the scientific community, we can take a moment to reflect on the role our field played in bringing East and West together. CERN’s collaboration with the East, primarily through links with the Joint Institute for Nuclear Research, JINR, in Dubna, Russia, is well documented. Less well known, however, is the role CERN played in bringing the scientists of East and West Germany together. As the Iron curtain was going up, particle physicists on both sides were already creating the conditions that would allow it to be torn down. Cold war historian Thomas Stange tells the story in his 2002 CERN Courier article. It was my privilege to be in Berlin on Monday, the anniversary of the wall’s opening, to take part in a conference entitled &lsquo...

  10. First wall

    International Nuclear Information System (INIS)

    Omori, Junji.

    1991-01-01

    Graphite and C/C composite are used recently for the first wall of a thermonuclear device since materials with small atom number have great impurity allowable capacity for plasmas. Among them, those materials having high thermal conduction are generally anisotropic and have an upper limit for the thickness upon production. Then, anisotropic materials are used for a heat receiving plate, such that the surfaces of the heat receiving plate on the side of lower heat conductivity are brought into contact with each other, and the side of higher thermal conductivity is arranged in parallel with small radius direction and the toroidal direction of the thermonuclear device. As a result, the incident heat on an edge portion can be transferred rapidly to the heat receiving plate, which can suppress the temperature elevation at the surface to thereby reduce the amount of abrasion. Since the heat expansion coefficient of the anisotropic materials is great in the direction of the lower heat conductivity and small in the direction of the higher heat conductivity, the gradient of a thermal load distribution in the direction of the higher heat expansion coefficient is small, and occurrence of thermal stresses due to temperature difference is reduced, to improve the reliability. (N.H.)

  11. Improving sustainability of striped catfish (Pangasianodon hypophthalmus) farming in the Mekong Delta, Vietnam through recirculation technology

    NARCIS (Netherlands)

    Nguyen, Nhut

    2016-01-01

    The aim of this thesis was to document improvements in sustainability indicators of striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878) production through the application of recirculation and waste treatment techniques. To be able to document improvements in sustainability, in each system

  12. Nonlocal Electron-Phonon Interaction as a Source of Dynamic Charge Stripes in the Cuprates

    Directory of Open Access Journals (Sweden)

    Claus Falter

    2012-01-01

    small pockets with reduced doping. We argue that the incompressibility of the orbital and simultaneously the compressibility of the orbital in the pseudogap state seem to be required to nucleate dynamic stripes.

  13. Striped Marlin Hardparts and Gonads Collected by the PIRO Hawaii Longline Observer Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Compilation of all samples collected from striped marlin (Tetrapturus audax) collected and brought to the Aiea Heights Research Facility by the PIRO Hawaii Longline...

  14. Complementary Response of Static Spin-Stripe Order and Superconductivity to Nonmagnetic Impurities in Cuprates

    Science.gov (United States)

    Guguchia, Z.; Roessli, B.; Khasanov, R.; Amato, A.; Pomjakushina, E.; Conder, K.; Uemura, Y. J.; Tranquada, J. M.; Keller, H.; Shengelaya, A.

    2017-08-01

    We report muon-spin rotation and neutron-scattering experiments on nonmagnetic Zn impurity effects on the static spin-stripe order and superconductivity of the La214 cuprates. Remarkably, it was found that, for samples with hole doping x ≈1 /8 , the spin-stripe ordering temperature Tso decreases linearly with Zn doping y and disappears at y ≈4 %, demonstrating a high sensitivity of static spin-stripe order to impurities within a CuO2 plane. Moreover, Tso is suppressed by Zn in the same manner as the superconducting transition temperature Tc for samples near optimal hole doping. This surprisingly similar sensitivity suggests that the spin-stripe order is dependent on intertwining with superconducting correlations.

  15. Evaluation of the effectiveness of centerline rumble stripes on rural roads.

    Science.gov (United States)

    2015-03-01

    This report documents the site characteristics, constructability, summary of audibility testing, and maintenance response of centerline rumble : stripes at two locations: US Route 4 in Mendon-Killington and VT Route 105 in Sheldon. : The primary obje...

  16. Histopathologic correlates of radial stripes on MR images in lysosomal storage disorders.

    NARCIS (Netherlands)

    Voorn, J.P. van der; Pouwels, P.J.; Kamphorst, W.; Powers, J.M.; Lammens, M.M.Y.; Barkhof, F.; Knaap, M.S. van der

    2005-01-01

    BACKGROUND AND PURPOSE: Radially oriented hypointense stripes in hyperintense cerebral white matter are recognized on T2-weighted images of certain lysosomal storage disorders. We compared in vivo and postmortem MR imaging with histopathologic findings in three patients with metachromatic

  17. Yr32 for resistance to stripe (yellow) rust present in the wheat cultivar Carstens V

    DEFF Research Database (Denmark)

    Eriksen, L.; Afshari, F.; Christiansen, M.J.

    2004-01-01

    Stripe or yellow rust of wheat, caused by Puccinia striiformis f. sp. tritici, is an important disease in many wheat-growing regions of the world. A number of major genes providing resistance to stripe rust have been used in breeding, including one gene that is present in the differential tester...... Carstens V. The objective of this study was to locate and map a stripe rust resistance gene transferred from Carstens V to Avocet S and to use molecular tools to locate a number of genes segregating in the cross Savannah/Senat. One of the genes present in Senat was predicted to be a gene that is present...... in Carstens V. For this latter purpose, stripe rust response data from both seedling and field tests on a doubled haploid population consisting of 77 lines were compared to an available molecular map for the same lines using a non-parametric quantitative trait loci (QTL) analysis. Results obtained in Denmark...

  18. Propagation of dark stripe beams in nonlinear media: Snake instability and creation of optical vortices

    DEFF Research Database (Denmark)

    Mamaev, A.V.; Saffman, M.; Zozulya, A.A.

    1996-01-01

    We analyze the evolution of (1+1) dimensional dark stripe beams in bulk media with a photorefractive nonlinear response. These beams, including solitary wave solutions, are shown to be unstable with respect to symmetry breaking and formation of structure along the initially homogeneous coordinate....... Experimental results show the complete sequence of events starting from self-focusing of the stripe, its bending due to the snake instability, and subsequent decay into a set of optical vortices....

  19. Topographic Organization of Inferior Olive Projections to the Zebrin II Stripes in the Pigeon Cerebellar Uvula

    Directory of Open Access Journals (Sweden)

    Iulia Craciun

    2018-03-01

    Full Text Available This study was aimed at mapping the organization of the projections from the inferior olive (IO to the ventral uvula in pigeons. The uvula is part of the vestibulocerebellum (VbC, which is involved in the processing of optic flow resulting from self-motion. As in other areas of the cerebellum, the uvula is organized into sagittal zones, which is apparent with respect to afferent inputs, the projection patterns of Purkinje cell (PC efferents, the response properties of PCs and the expression of molecular markers such as zebrin II (ZII. ZII is heterogeneously expressed such that there are sagittal stripes of PCs with high ZII expression (ZII+, alternating with sagittal stripes of PCs with little to no ZII expression (ZII−. We have previously demonstrated that a ZII+/− stripe pair in the uvula constitutes a functional unit, insofar as the complex spike activity (CSA of all PCs within a ZII+/− stripe pair respond to the same type of optic flow stimuli. In the present study we sought to map the climbing fiber (CF inputs from the IO to the ZII+ and ZII− stripes in the uvula. We injected fluorescent Cholera Toxin B (CTB of different colors (red and green into ZII+ and ZII− bands of functional stripe pair. Injections in the ZII+ and ZII− bands resulted in retrograde labeling of spatially separate, but adjacent regions in the IO. Thus, although a ZII+/− stripe pair represents a functional unit in the pigeon uvula, CF inputs to the ZII+ and ZII− stripes of a unit arise from separate regions of the IO.

  20. Stripe patterns in a granular system induced by slow deformation of its container

    OpenAIRE

    Kitsunezaki, So; Kurumatani, Akemi

    2001-01-01

    We investigate the formation of stripe patterns that appear on the surface of a dry granular system as the container is deformed very slowly. In an experimental study using nearly mono-disperse glass beads, we found that many faults develop beneath t he surface. Our results show that the spacing of stripes is independent of the system size and does not depend significantly on the grain size.