WorldWideScience

Sample records for spin ladder structure

  1. Doped spin ladders under magnetic field

    International Nuclear Information System (INIS)

    Roux, G.

    2007-07-01

    This thesis deals with the physics of doped two-leg ladders which are a quasi one-dimensional and unconventional superconductor. We particularly focus on the properties under magnetic field. Models for strongly correlated electrons on ladders are studied using exact diagonalization and density-matrix renormalization group (DMRG). Results are also enlightened by using the bosonization technique. Taking into account a ring exchange it highlights the relation between the pairing of holes and the spin gap. Its influence on the dynamics of the magnetic fluctuations is also tackled. Afterwards, these excitations are probed by the magnetic field by coupling it to the spin degree of freedom of the electrons through Zeeman effect. We show the existence of doping-dependent magnetization plateaus and also the presence of an inhomogeneous superconducting phase (FFLO phase) associated with an exceeding of the Pauli limit. When a flux passes through the ladder, the magnetic field couples to the charge degree of freedom of the electrons via orbital effect. The diamagnetic response of the doped ladder probes the commensurate phases of the t-J model at low J/t. Algebraic transverse current fluctuations are also found once the field is turned on. Lastly, we report numerical evidences of a molecular superfluid phase in the 3/2-spin attractive Hubbard model: at a density low enough, bound states of four fermions, called quartets, acquire dominant superfluid fluctuations. The observed competition between the superfluid and density fluctuations is connected to the physics of doped ladders. (author)

  2. Ladder Ising spin configurations. Pt. 1. Heat capacity

    International Nuclear Information System (INIS)

    Mejdani, R.; Lambros, A.

    1996-01-01

    We consider a ladder Ising spin model (with two coupled Ising spin chains), characterized by two couplings (interchain and intrachain couplings), to study in detail, in an analytical way, its thermal behaviour and particularly the variation of the specific heat versus temperature, the ratio of interaction constants, and the magnetic field. It is interesting that when the competition between interchain and intrachain interactions is strong the specific heat exhibits a double peak and when the competition is not so strong the specific heat has a single peak. Further, without entering into details, we give, in a numerical way, some similar results for more complicated ladder configurations (with more than two linear Ising chains). The spin-1/2 ladders or systems of spin chains may be realized in nature by vanadyl pyrophosphate ((VO) 2 P 2 O 7 ) or similar materials. All these intermediate systems are today important to gain further insight into the physics of one-dimensional spin chains and two-dimensional high-T c spin systems, both of which have shown interesting and unusual magnetic and superconducting properties. It is plausible that experimental and theoretical studies of ladders may lead to other interesting physical phenomena. (orig.)

  3. Impact of inter-ladder coupling in a coupled spin-1/2 two-leg ladder

    Science.gov (United States)

    Hong, Tao; Schmidt, K. P.; Coester, K.; Awwadi, F. F.; Turnbull, M. M.; Qiu, Y.; Rodriguez, J. A.; Ke, X.; Aoyama, C.; Takano, Y.; Cao, H.; Tian, W.; Ma, J.; Custelcean, R.; Zhou, H. D.; Matsuda, M.

    2014-03-01

    We present the zero-field specific heat and neutron scattering studies on an S = 1/2 Heisenberg antiferromagnet to understand the nature of its spin Hamiltonian. The system is magnetically ordered below TN = 2.0(1) K. The conclusion that the system is best described as coupled two-leg spin-1/2 ladders is supported by the material structure, neutron scattering measurements, and theoretical calculation. The work at the HFIR, ORNL was sponsored by the Division of Scientific User Facilities, Office of Basic Energy Science, US Department of Energy.

  4. Elementary excitations and thermodynamics of zig-zag spin ladders with alternating nearest neighbor exchange interactions

    International Nuclear Information System (INIS)

    Zvyagin, A.A.; Cheranovskii, V.O.

    2009-01-01

    A one-dimensional spin-1/2 model in which the alternation of the exchange interactions between neighboring spins is accompanied by the next-nearest-neighbor (NNN) spin exchange (zig-zag spin ladder with alternation) is studied. The thermodynamic characteristics of the model quantum spin chain are obtained in the mean-field-like approximation. Depending on the strength of the NNN interactions, the model manifests either the spin-gapped behavior of low-lying excitations at low magnetic fields, or ferrimagnetic ordering in the ground state with gapless low-lying excitations. The system undergoes second-order or first-order quantum phase transitions, governed by the external magnetic field, NNN coupling strength, and the degree of the alternation. Hence, NNN spin-spin interactions in a dimerized quantum spin chain can produce a spontaneous magnetization. On the other hand, for quantum spin chains with a spontaneous magnetization, caused by NNN spin-spin couplings, the alternation of nearest-neighbor (NN) exchange interactions can cause destruction of that magnetization and the onset of a spin gap for low-lying excitations. Alternating NN interactions produce a spin gap between two branches of low-energy excitations, and the NNN interactions yield asymmetry of the dispersion laws of those excitations, with possible minima corresponding to incommensurate structures in the spin chain

  5. Frustrated spin-1/2 ladder with ferro- and antiferromagnetic legs

    Science.gov (United States)

    Maiti, Debasmita; Dey, Dayasindhu; Kumar, Manoranjan

    2018-01-01

    Two-leg spin-1/2 ladder systems consisting of a ferromagnetic leg and an antiferromagnetic leg are considered where the spins on the legs interact through antiferromagnetic rung couplings J1 . These ladders can have two geometrical arrangements either zigzag or normal ladder and these systems are frustrated irrespective of their geometry. This frustration gives rise to incommensurate spin density wave, dimer and spin fluid phases in the ground state. The magnetization in the systems decreases linearly with J12, and the systems show an incommensurate phase for 0.0 spin-spin correlation functions in the incommensurate phase follow power law decay which is very similar to Heisenberg antiferromagnetic chain in external magnetic field. In large J1 limit, the normal ladder behaves like a collection of singlet dimers, whereas the zigzag ladder behaves as a one dimensional spin-1/2 antiferromagnetic chain.

  6. Doped spin ladders under magnetic field; Echelles de spins dopees sous champ magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Roux, G

    2007-07-15

    This thesis deals with the physics of doped two-leg ladders which are a quasi one-dimensional and unconventional superconductor. We particularly focus on the properties under magnetic field. Models for strongly correlated electrons on ladders are studied using exact diagonalization and density-matrix renormalization group (DMRG). Results are also enlightened by using the bosonization technique. Taking into account a ring exchange it highlights the relation between the pairing of holes and the spin gap. Its influence on the dynamics of the magnetic fluctuations is also tackled. Afterwards, these excitations are probed by the magnetic field by coupling it to the spin degree of freedom of the electrons through Zeeman effect. We show the existence of doping-dependent magnetization plateaus and also the presence of an inhomogeneous superconducting phase (FFLO phase) associated with an exceeding of the Pauli limit. When a flux passes through the ladder, the magnetic field couples to the charge degree of freedom of the electrons via orbital effect. The diamagnetic response of the doped ladder probes the commensurate phases of the t-J model at low J/t. Algebraic transverse current fluctuations are also found once the field is turned on. Lastly, we report numerical evidences of a molecular superfluid phase in the 3/2-spin attractive Hubbard model: at a density low enough, bound states of four fermions, called quartets, acquire dominant superfluid fluctuations. The observed competition between the superfluid and density fluctuations is connected to the physics of doped ladders. (author)

  7. Nested Bethe Ansatz for Spin Ladder Model with Open Boundary Conditions

    International Nuclear Information System (INIS)

    Wu Junfang; Zhang Chunmin; Yue Ruihong; Li Runling

    2005-01-01

    The nested Bethe ansatz (BA) method is applied to find the eigenvalues and the eigenvectors of the transfer matrix for spin-ladder model with open boundary conditions. Based on the reflection equation, we find the general diagonal solution, which determines the general boundary interaction in the Hamiltonian. We introduce the spin-ladder model with open boundary conditions. By finding the solution K ± of the reflection equation which determines the nontrivial boundary terms in the Hamiltonian, we diagonalize the transfer matrix of the spin-ladder model with open boundary conditions in the framework of nested BA.

  8. Magnetic dimerization in the frustrated spin ladder Li2Cu2O (SO4)2

    Science.gov (United States)

    Vaccarelli, O.; Rousse, G.; Saúl, A.; Radtke, G.

    2017-11-01

    The magnetic properties of Li2Cu2O (SO4)2 are investigated in the framework of density functional theory. In its high-temperature tetragonal structure, this compound appears as a rare material realization of a frustrated spin-1/2 two-leg ladder, where magnetic frustration arises from competing nearest and next-nearest interactions along the legs. Through a large magnetoelastic coupling, the triclinic distortion occurring around 125 K is shown to induce the formation of a staggered dimer structure, lifting most of the magnetic frustration.

  9. Spin-1/2 Heisenberg ladder: variation of entanglement and fidelity measures close to quantum critical points

    OpenAIRE

    Tribedi, Amit; Bose, Indrani

    2008-01-01

    We consider a two-chain, spin-1/2 antiferromagnetic Heisenberg spin ladder in an external magnetic field H. The spin ladder is known to undergo second order quantum phase transitions (QPTs) at two critical values, Hc1 and Hc2, of the magnetic field. There are now known examples of strongly coupled (rung exchange interaction much stronger than nearest-neighbour intrachain exchange interaction) organic ladder compounds in which QPTs have been experimentally observed. In this paper, we investiga...

  10. Groundstate fidelity phase diagram of the fully anisotropic two-leg spin-½ XXZ ladder

    Science.gov (United States)

    Li, Sheng-Hao; Shi, Qian-Qian; Batchelor, Murray T.; Zhou, Huan-Qiang

    2017-11-01

    The fully anisotropic two-leg spin-\\tfrac{1}{2} XXZ ladder model is studied in terms of an algorithm based on the tensor network (TN) representation of quantum many-body states as an adaptation of projected entangled pair states to the geometry of translationally invariant infinite-size quantum spin ladders. The TN algorithm provides an effective method to generate the groundstate wave function, which allows computation of the groundstate fidelity per lattice site, a universal marker to detect phase transitions in quantum many-body systems. The groundstate fidelity is used in conjunction with local order and string order parameters to systematically map out the groundstate phase diagram of the ladder model. The phase diagram exhibits a rich diversity of quantum phases. These are the ferromagnetic, stripe ferromagnetic, rung singlet, rung triplet, Néel, stripe Néel and Haldane phases, along with the two XY phases XY1 and XY2.

  11. Hadron structure in the ladder model

    Energy Technology Data Exchange (ETDEWEB)

    Soper, D.E.

    1979-01-01

    The (flavor non-singlet) Green's function to find a far-off-shell quark in a hadron is obtained in the renormalization group improved ladder model for QCD in the space-like axial gauge. Particular attention is paid to the role of the singularity in the gluon propagator. 4 figures.

  12. Optical probing of anisotropic heat transport in the quantum spin ladder Ca9La5Cu24O41

    NARCIS (Netherlands)

    Otter, M.; Athanasopoulos, G.; Hlubek, N.; Montagnese, M.; Labois, M.; Fishman, D. A.; de Haan, F.; Singh, S.; Lakehal, D.; Giapintzakis, J.; Hess, C.; Revcolevschi, A.; van Loosdrecht, P. H. M.

    A transient thermal imaging technique is used to monitor heat diffusion at the surface of the antiferromagnetic spin ladder material Ca9La5Cu24O41. This material shows highly anisotropic thermal conductivity due to a large uni-directional magnetic heat transport along the ladders. The thermal

  13. Controlling Luttinger liquid physics in spin ladders under a magnetic field.

    Science.gov (United States)

    Klanjsek, M; Mayaffre, H; Berthier, C; Horvatić, M; Chiari, B; Piovesana, O; Bouillot, P; Kollath, C; Orignac, E; Citro, R; Giamarchi, T

    2008-09-26

    We present a 14N nuclear magnetic resonance study of a single crystal of CuBr4(C5H12N)2 (BPCB) consisting of weakly coupled spin-1/2 Heisenberg antiferromagnetic ladders. Treating ladders in the gapless phase as Luttinger liquids, we are able to fully account for (i) the magnetic field dependence of the nuclear spin-lattice relaxation rate T1(-1) at 250 mK and for (ii) the phase transition to a 3D ordered phase occurring below 110 mK due to weak interladder exchange coupling. BPCB is thus an excellent model system where the possibility to control Luttinger liquid parameters in a continuous manner is demonstrated and the Luttinger liquid model tested in detail over the whole fermion band.

  14. Phase transitions and magnetization of the mixed-spin Ising–Heisenberg double sawtooth frustrated ladder

    Science.gov (United States)

    Arian Zad, Hamid; Ananikian, Nerses

    2018-04-01

    The mixed spin-(1,1/2) Ising–Heisenberg double sawtooth ladder containing a mixture of both spin-1 and spin-1/2 nodal atoms, and the spin-1/2 interstitial dimers are approximately solved by the transfer-matrix method. Here, we study in detail the ground-state phase diagrams, also influences of the bilinear exchange coupling on the rungs and cyclic four-spin exchange interaction in square plaquette of each block on the magnetization and magnetic susceptibility of the suggested ladder at low temperature. Such a double sawtooth ladder may be found in a Shastry-Sutherland lattice-type. In spite of the spin ordering of odd and even blocks being different from each other, due to the commutation relation between all different block Hamiltonians, phase diagrams, magnetization behavior and thermodynamic properties of the model are the same for odd and even blocks. We show that at low temperature, both exchange couplings can change the quality and quantity of the magnetization plateaus versus the magnetic field changes. Specially, we find a new magnetization plateau M/Ms= 5/6 for this model. Besides, we examine the magnetic susceptibility and specific heat of the model in detail. It is proven that behaviors of the magnetization and the magnetic susceptibility coincide at low temperature. The specific heat displays diverse temperature dependencies, which include a Schottky-type peak at a special temperature interval. We observe that with increase of the bilinear exchange coupling on the rungs, second peak temperature dependence grows.

  15. Phase transitions and thermal entanglement of the distorted Ising-Heisenberg spin chain: topology of multiple-spin exchange interactions in spin ladders

    Science.gov (United States)

    Arian Zad, Hamid; Ananikian, Nerses

    2017-11-01

    We consider a symmetric spin-1/2 Ising-XXZ double sawtooth spin ladder obtained from distorting a spin chain, with the XXZ interaction between the interstitial Heisenberg dimers (which are connected to the spins based on the legs via an Ising-type interaction), the Ising coupling between nearest-neighbor spins of the legs and rungs spins, respectively, and additional cyclic four-spin exchange (ring exchange) in the square plaquette of each block. The presented analysis supplemented by results of the exact solution of the model with infinite periodic boundary implies a rich ground state phase diagram. As well as the quantum phase transitions, the characteristics of some of the thermodynamic parameters such as heat capacity, magnetization and magnetic susceptibility are investigated. We prove here that among the considered thermodynamic and thermal parameters, solely heat capacity is sensitive versus the changes of the cyclic four-spin exchange interaction. By using the heat capacity function, we obtain a singularity relation between the cyclic four-spin exchange interaction and the exchange coupling between pair spins on each rung of the spin ladder. All thermal and thermodynamic quantities under consideration should be investigated by regarding those points which satisfy the singularity relation. The thermal entanglement within the Heisenberg spin dimers is investigated by using the concurrence, which is calculated from a relevant reduced density operator in the thermodynamic limit.

  16. Quantum phase transitions in effective spin-ladder models for graphene zigzag nanoribbons

    Science.gov (United States)

    Koop, Cornelie; Wessel, Stefan

    2017-10-01

    We examine the magnetic correlations in quantum spin models that were derived recently as effective low-energy theories for electronic correlation effects on the edge states of graphene nanoribbons. For this purpose, we employ quantum Monte Carlo simulations to access the large-distance properties, accounting for quantum fluctuations beyond mean-field-theory approaches to edge magnetism. For certain chiral nanoribbons, antiferromagnetic interedge couplings were previously found to induce a gapped quantum disordered ground state of the effective spin model. We find that the extended nature of the intraedge couplings in the effective spin model for zigzag nanoribbons leads to a quantum phase transition at a large, finite value of the interedge coupling. This quantum critical point separates the quantum disordered region from a gapless phase of stable edge magnetism at weak intraedge coupling, which includes the ground states of spin-ladder models for wide zigzag nanoribbons. To study the quantum critical behavior, the effective spin model can be related to a model of two antiferromagnetically coupled Haldane-Shastry spin-half chains with long-ranged ferromagnetic intrachain couplings. The results for the critical exponents are compared also to several recent renormalization-group calculations for related long-ranged interacting quantum systems.

  17. Field-controlled magnetic order in the quantum spin-ladder system (Hpip)2CuBr4

    DEFF Research Database (Denmark)

    Thielemann, B.; Rüegg, C.; Kiefer, K.

    2009-01-01

    Neutron diffraction is used to investigate the field-induced, antiferromagnetically ordered state in the two-leg spin-ladder material (Hpip)(2)CuBr4. This "classical" phase, a consequence of weak interladder coupling, is nevertheless highly unconventional: its properties are influenced strongly b...... the quantum fluctuation corrections to the mean-field interaction.......Neutron diffraction is used to investigate the field-induced, antiferromagnetically ordered state in the two-leg spin-ladder material (Hpip)(2)CuBr4. This "classical" phase, a consequence of weak interladder coupling, is nevertheless highly unconventional: its properties are influenced strongly...

  18. Heat transport imaging in the spin-ladder compound Ca9La5Cu24O41

    NARCIS (Netherlands)

    Otter, M.; Krasnikov, V. V.; Fishman, D. A.; Pshenichnikov, M. S.; Saint-Martin, R.; Revcolevschi, A.; van Loosdrecht, P. H. M.

    All-optical heat transport imaging on the spin-ladder compound Ca9La5Cu24O41 is presented. A 'time-of-flight' principle is discussed along with its experimental veri. cation which can be used to measure the bulk thermal diffusion constant. The results of the thermal imaging experiments clearly

  19. Spin- (1)/(2) Heisenberg ladder: Variation of entanglement and fidelity measures close to quantum critical points

    Science.gov (United States)

    Tribedi, Amit; Bose, Indrani

    2009-01-01

    We consider a two-chain, spin- (1)/(2) antiferromagnetic Heisenberg spin ladder in an external magnetic field H . The spin ladder is known to undergo second-order quantum phase transitions (QPTs) at two critical values Hc1 and Hc2 of the magnetic field. There are now known examples of strongly coupled (where the rung exchange interaction is much stronger than the nearest-neighbor intrachain exchange interaction) organic ladder compounds in which QPTs have been experimentally observed. In this paper, we investigate whether well-known bipartite entanglement meaures such as one-site von Neumann entropy, two-site von Neumann entropy, and concurrence develop special features close to the quantum critical points. As suggested by an earlier theorem, the first derivatives of the measures with respect to magnetic field are expected to diverge as H→Hc1 and H→Hc2 . Based on numerical diagonalization data and a mapping of the strongly coupled ladder Hamiltonian onto the XXZ chain Hamiltonian, for which several analytical results are known, we find that the derivatives of the entanglement measures diverge as H→Hc2 but remain finite as H→Hc1 . The reason for this discrepancy is analyzed. We further calculate two recently proposed quantum information theoretic measures, the reduced fidelity and reduced fidelity susceptibility, and show that these measures provide appropriate signatures of the QPTs occuring at the critical points H=Hc1 and H=Hc2 .

  20. The Structure of Opportunity: How Promotion Ladders Vary within and among Organizations.

    Science.gov (United States)

    Baron, James N.; And Others

    1986-01-01

    Data describing jobs in 100 establishments are analyzed to test hypotheses about the characteristics of jobs and organizations associated with the structure of internal promotion ladders. Hypotheses are supported that link job ladders to, for example, organizational structure, gender distinctions, and technology. The formation of promotion ladders…

  1. The incidence and burden of ladder, structure, and scaffolding falls.

    Science.gov (United States)

    Diggs, Brian S; Lenfesty, Barbara; Arthur, Melanie; Hedges, Jerris R; Newgard, Craig D; Mullins, Richard J

    2005-03-01

    The national morbidity and mortality associated with falls from a height is incompletely described. The authors estimated the rates of injury, hospitalization, and mortality due to these falls for subgroups of the U.S. population. Administrative databases (1995-2000) provided national samples of patients treated for injuries following a fall from a height (ICD-9-CM E-codes E881.0, E881.1, or E882). Inpatient data are from the Nationwide Inpatient Sample, and emergency department data are from the National Hospital Ambulatory Medical Care Survey. A total of 347,484 (95% confidence interval = 308,417 to 386,551) emergency department presentations occur annually for injuries following a fall. Hospitalized patients older than 75 years of age had a 3.3% case fatality, and 42% were discharged to a skilled nursing facility. For patients older than 55 years of age, 86% of falls were not work related. Ladder and structure falls by elders are a substantial emergency department problem warranting thorough clinical evaluation and injury prevention efforts.

  2. Structural evolution of one-dimensional spin-ladder compounds Sr.sub.14-x./sub.Ca.sub.x./sub.Cu.sub.24./sub.O.sub.41./sub. with Ca doping and related evidence of hole redistribution

    Czech Academy of Sciences Publication Activity Database

    Deng, G.; Pomjakushin, V.; Petříček, Václav; Pomjakushina, E.; Kenzelmann, M.; Conder, K.

    2011-01-01

    Roč. 84, č. 14 (2011), 144111/1-144111/14 ISSN 1098-0121 Grant - others:AV ČR(CZ) AP0701 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : composite crystal-structures * true satellite reflections * Sr 14 Cu 24 O 41 * pressure * superconductivity * dynamics * phases * charge Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.691, year: 2011

  3. Spin Structures in Magnetic Nanoparticles

    DEFF Research Database (Denmark)

    Mørup, Steen; Brok, Erik; Frandsen, Cathrine

    2013-01-01

    Spin structures in nanoparticles of ferrimagnetic materials may deviate locally in a nontrivial way from ideal collinear spin structures. For instance, magnetic frustration due to the reduced numbers of magnetic neighbors at the particle surface or around defects in the interior can lead to spin...... canting and hence a reduced magnetization. Moreover, relaxation between almost degenerate canted spin states can lead to anomalous temperature dependences of the magnetization at low temperatures. In ensembles of nanoparticles, interparticle exchange interactions can also result in spin reorientation...

  4. Electronic states of doped spin ladders (Sr,Ca)14Cu24O41

    International Nuclear Information System (INIS)

    Mizuno, Yoshiaki; Tohyama, Takami; Maekawa, Sadamichi.

    1997-01-01

    We examine the electronic states of Sr 14-x Ca x Cu 24 O 41 by the ionic and cluster model approach. It is found that self-doped holes are likely to stay on the chain at x = 0 and Ca substitution drives the holes to move to the ladder. This feature is caused by changes of the positions of (Sr,Ca) layers, which results in enhancement of the electrostatic potentials in the chain. The optical conductivity is calculated with application of the exact diagonalization method to small Cu-O clusters. It is shown that the excitations below 2 eV are governed by the ladder, giving rise to the spectral weight transfer from the charge-transfer excitation at around 2 eV to low energy Drude excitation, while the contribution from the chain mainly emerges in a higher energy region showing large spectral weight at around 3 eV. These findings provide a consistent explanation for the results of a recent experiment. (author)

  5. Ground-state phase diagram, fermionic entanglement and kinetically-induced frustration in a hybrid ladder with localized spins and mobile electrons

    Science.gov (United States)

    Carvalho, R. C. P.; Pereira, M. S. S.; de Oliveira, I. N.; Strečka, J.; Lyra, M. L.

    2017-09-01

    We introduce an exactly solvable hybrid spin-ladder model containing localized nodal Ising spins and interstitial mobile electrons, which are allowed to perform a quantum-mechanical hopping between the ladder’s legs. The quantum-mechanical hopping process induces an antiferromagnetic coupling between the ladder’s legs that competes with a direct exchange coupling of the nodal spins. The model is exactly mapped onto the Ising spin ladder with temperature-dependent two- and four-spin interactions, which is subsequently solved using the transfer-matrix technique. We report the ground-state phase diagram and compute the fermionic concurrence to characterize the quantum entanglement between the pair of interstitial mobile electrons. We further provide a detailed analysis of the local spin ordering including the pair and four-spin correlation functions around an elementary plaquette, as well as, the local ordering diagrams. It is shown that a complex sequence of distinct local orderings and frustrated correlations takes place when the model parameters drive the investigated system close to a zero-temperature triple coexistence point.

  6. Spin-orbit coupling, electron transport and pairing instabilities in two-dimensional square structures

    Directory of Open Access Journals (Sweden)

    Armen N. Kocharian

    2016-05-01

    Full Text Available Rashba spin-orbit effects and electron correlations in the two-dimensional cylindrical lattices of square geometries are assessed using mesoscopic two-, three- and four-leg ladder structures. Here the electron transport properties are systematically calculated by including the spin-orbit coupling in tight binding and Hubbard models threaded by a magnetic flux. These results highlight important aspects of possible symmetry breaking mechanisms in square ladder geometries driven by the combined effect of a magnetic gauge field spin-orbit interaction and temperature. The observed persistent current, spin and charge polarizations in the presence of spin-orbit coupling are driven by separation of electron and hole charges and opposite spins in real-space. The modeled spin-flip processes on the pairing mechanism induced by the spin-orbit coupling in assembled nanostructures (as arrays of clusters engineered in various two-dimensional multi-leg structures provide an ideal playground for understanding spatial charge and spin density inhomogeneities leading to electron pairing and spontaneous phase separation instabilities in unconventional superconductors. Such studies also fall under the scope of current challenging problems in superconductivity and magnetism, topological insulators and spin dependent transport associated with numerous interfaces and heterostructures.

  7. Spin Structure Analyses of Antiferromagnets

    International Nuclear Information System (INIS)

    Chung, Jae Ho; Song, Young Sang; Lee, Hak Bong

    2010-05-01

    We have synthesized series of powder sample of incommensurate antiferromagnetic multiferroics, (Mn, Co)WO 4 and Al doped Ba 0.5 Sr 1.5 Zn 2 Fe 12 O 22 , incommensurate antiferromagnetic multiferroics. Their spin structure was studied by using the HRPD. In addition, we have synthesized series of crystalline samples of incommensurate multiferroics, (Mn, Co)WO 4 and olivines. Their spin structure was investigated using neutron diffraction under high magnetic field. As a result, we were able to draw the phase diagram of (Mn, Co)WO 4 as a function of composition and temperature. We learned the how the spin structure changes with increased ionic substitution. Finally we have drawn the phase diagram of the multicritical olivine Mn2SiS4/Mn2GeS4 as a function of filed and temperature through the spin structure studies

  8. Magnetic susceptibilities of integrable quantum ladders

    International Nuclear Information System (INIS)

    Park, Soo A; Lee, K.

    2001-01-01

    As an extension of previous studies, we consider the magnetic susceptibilities of a coupled spin chain model at low temperature and of a more realistic model at low temperature and of a more realistic model having a t-J ladder structure at zero temperature. The magnetic susceptibilities for both models are obtained numerically when the coupling constant is greater than its critical value. In this region, the ladders behave as a single chain for H c and as two independent chains for H>H c , showing a divergence at H c . This divergence is expected to smear out at a finite temperature

  9. Spin structures in antiferromagnetic nanoparticles

    DEFF Research Database (Denmark)

    Brok, Erik

    a detailed knowledge of it can be important for applications of antiferromagnetic nanoparticles for example combined with ferromagnetic nanoparticles in nanocomposite devices. In this thesis the magnetic structure, in particular the orientation of the spins in the antiferromagnetic sublattices......, proposed to explain the unusual magnetic properties of the mineral. In summary the thesis have demonstrated methods for investigation of spin structures in magnetic nanoparticles. In particular, the classical model of the temperature dependence of canted spin structures sucessfully explains many...... experimental observations of anomalous temperature dependence in nanoparticle and bulk systems. Morover, XY Z neutron polarisation analysis have been demonstrated to be an effective way of investigating the magnetic properties of antiferromagnetic nanoparticles, significantly improving the unpolarised neutron...

  10. Spin flexoelectricity and chiral spin structures in magnetic films

    OpenAIRE

    Pyatakov, A. P.; Sergeev, A. S.; Mikailzade, F. A.; Zvezdin, A. K.

    2015-01-01

    In this short review a broad range of chiral phenomena observed in magnetic films (spin cycloid and skyrmion structures formation as well as chirality dependent domain wall motion) is considered under the perspective of spin flexoelectricity, i.e. the relation between bending of magnetization pattern and electric polarization. The similarity and the difference between the spin flexoelectricity and the newly emerged notion of spin flexomagnetism is discussed. The phenomenological arguments bas...

  11. Spin flexoelectricity and chiral spin structures in magnetic films

    Science.gov (United States)

    Pyatakov, A. P.; Sergeev, A. S.; Mikailzade, F. A.; Zvezdin, A. K.

    2015-06-01

    In this short review a broad range of chiral phenomena observed in magnetic films (spin cycloid and skyrmion structures formation as well as chirality dependent domain wall motion) is considered under the perspective of spin flexoelectricity, i.e. the relation between bending of magnetization pattern and electric polarization. The similarity and the difference between the spin flexoelectricity and the newly emerged notion of spin flexomagnetism are discussed. The phenomenological arguments based on the geometrical idea of curvature-induced effects are supported by analysis of the microscopic mechanisms of spin flexoelectricity based on three-site ion indirect exchange and twisted RKKY interaction models.

  12. Ground state of a spin-1/2 Heisenberg-Ising two-leg ladder with XYZ intra-rung coupling

    Directory of Open Access Journals (Sweden)

    T. Verkholyak

    2013-03-01

    Full Text Available The quantum spin-1/2 two-leg ladder with an anisotropic XYZ Heisenberg intra-rung interaction and Ising inter-rung interactions is treated by means of a rigorous approach based on the unitary transformation. The particular case of the considered model with X-X intra-rung interaction resembles a quantum compass ladder with additional frustrating diagonal Ising interactions. Using an appropriately chosen unitary transformation, the model under investigation may be reduced to a transverse Ising chain with composite spins, and one may subsequently find the ground state quite rigorously. We obtain a ground-state phase diagram and analyze the interplay of the competition between several factors: the XYZ anisotropy in the Heisenberg intra-rung coupling, the Ising interaction along the legs, and the frustrating diagonal Ising interaction. The investigated model shows extraordinarily diverse ground-state phase diagrams including several unusual quantum ordered phases, two different disordered quantum paramagnetic phases, as well as discontinuous or continuous quantum phase transitions between those phases.

  13. Measuring subjective meaning structures by the laddering method: Theoretical considerations and methodological problems

    DEFF Research Database (Denmark)

    Grunert, Klaus G.; Grunert, Suzanne C.

    1995-01-01

    and applied, which refer to data collection, coding, and analysis. These criteria are evaluated using examples from a laddering study where additional data was collected to shed light on respondents' subj interpretation of the laddering task as well as interviewers' experiences with it. Several possible...

  14. Double-helical - ladder structural transition in the B-DNA is induced by a loss of dispersion energy

    Czech Academy of Sciences Publication Activity Database

    Černý, Jiří; Kabeláč, Martin; Hobza, Pavel

    2008-01-01

    Roč. 130, č. 47 (2008), s. 16055-16059 ISSN 0002-7863 R&D Projects: GA MŠk LC512; GA AV ČR IAA400550808 Institutional research plan: CEZ:AV0Z40550506 Keywords : B-DNA * double-helical structure * ladder-like structure Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 8.091, year: 2008

  15. Spin flexoelectricity and chiral spin structures in magnetic films

    International Nuclear Information System (INIS)

    Pyatakov, A.P.; Sergeev, A.S.; Mikailzade, F.A.; Zvezdin, A.K.

    2015-01-01

    In this short review a broad range of chiral phenomena observed in magnetic films (spin cycloid and skyrmion structures formation as well as chirality dependent domain wall motion) is considered under the perspective of spin flexoelectricity, i.e. the relation between bending of magnetization pattern and electric polarization. The similarity and the difference between the spin flexoelectricity and the newly emerged notion of spin flexomagnetism are discussed. The phenomenological arguments based on the geometrical idea of curvature-induced effects are supported by analysis of the microscopic mechanisms of spin flexoelectricity based on three-site ion indirect exchange and twisted RKKY interaction models. - Highlights: • Magnetic structure formation in thin films is analogous to flexoelectric phenomena in crystals. • The microscopic mechanism of spin flexoelectricity is the antisymmetric exchange. • Spin cycloid in thin film of metals can be the result of Rashba interaction in 2DEG. • The chirality-dependent Néel-type magnetic domain wall motion is observed in electric field

  16. Spin flexoelectricity and chiral spin structures in magnetic films

    Energy Technology Data Exchange (ETDEWEB)

    Pyatakov, A.P., E-mail: pyatakov@physics.msu.ru [M.V. Lomonosov Moscow State University, Leninskie gori, Moscow 119991 (Russian Federation); Sergeev, A.S. [M.V. Lomonosov Moscow State University, Leninskie gori, Moscow 119991 (Russian Federation); Mikailzade, F.A. [Department of Physics, Gebze Technical University, Gebze, 41400 Kocaeli (Turkey); Zvezdin, A.K. [A.M. Prokhorov General Physics Institute, Vavilova St., 38, Moscow 119991 (Russian Federation)

    2015-06-01

    In this short review a broad range of chiral phenomena observed in magnetic films (spin cycloid and skyrmion structures formation as well as chirality dependent domain wall motion) is considered under the perspective of spin flexoelectricity, i.e. the relation between bending of magnetization pattern and electric polarization. The similarity and the difference between the spin flexoelectricity and the newly emerged notion of spin flexomagnetism are discussed. The phenomenological arguments based on the geometrical idea of curvature-induced effects are supported by analysis of the microscopic mechanisms of spin flexoelectricity based on three-site ion indirect exchange and twisted RKKY interaction models. - Highlights: • Magnetic structure formation in thin films is analogous to flexoelectric phenomena in crystals. • The microscopic mechanism of spin flexoelectricity is the antisymmetric exchange. • Spin cycloid in thin film of metals can be the result of Rashba interaction in 2DEG. • The chirality-dependent Néel-type magnetic domain wall motion is observed in electric field.

  17. 29 CFR 1917.118 - Fixed ladders.

    Science.gov (United States)

    2010-07-01

    ... and fastened to one or both of the ladder's side rails or to another structure. (2) Fixed ladder means... walls of the well. (c) Defects. (1) Ladders with broken, split or missing rungs, steps or rails, broken welds or connections, corrosion or wastage or other defect which may affect safe use shall be removed...

  18. Crystal growth under high pressure: preparation of the spin-ladder compound SrCu sub 2 O sub 3

    CERN Document Server

    Loeffert, A; Assmus, W

    2002-01-01

    The two-leg ladder SrCu sub 2 O sub 3 belongs to the homologous series Sr sub n sub sub - sub 1 Cu sub n O sub 2 sub n sub - sub 1 and was first synthesized by Hiroi et al (Hiroi Z, Azuma M, Takano M and Bando Y 1991 J. Solid State Chem. 95 230). Due to the massive reaction of the sample material with the crucible (Au or Pt), only short reaction times up to 30 min have been used typically. We suggest an improved composite crucible with a single-crystalline MgO inset in a sealed Pt capsule and demonstrate its capability for single-crystal growth of SrCu sub 2 O sub 3. Experiments with a typical duration of 15 h were conducted at pressures between 3 and 6 GPa at temperatures between 950 and 1500 deg. C. Slow cooling of the melt effected directed growth of the first SrCu sub 2 O sub 3 milimetre-sized single crystals.

  19. Structure of the conversion laws in quantum integrable spin chains with short range interactions

    International Nuclear Information System (INIS)

    Grabowski, M.P.; Mathieu, P.

    1995-01-01

    The authors present a detailed analysis of the structure of the conservation laws in quantum integrable chains of the XYZ-type and in the Hubbard model. The essential tool for the former class of models is the boost operator, which provides a recursive way of calculating the integrals of motion. With its help, they establish the general form of the XYZ conserved charges in terms of simple polynomials in spin variables and derive recursion relations for the relative coefficients of these polynomials. Although these relations are difficult to solve in general, a subset of the coefficients can be determined. Moreover, for two submodels of the XYZ chain, namely the XXX and XY cases, all the charges can be calculated in closed form. Using this approach, the authors rederive the known expressions for the XY charges in a novel way. For the XXX case. a simple description of conserved charges is found in terms of a Catalan tree. This construction is generalized for the su(M) invariant integrable chain. They also investigate the circumstances permitting the existence of a recursive (ladder) operator in general quantum integrable systems. They indicate that a quantum ladder operator can be traced back to the presence of a Hamiltonian mastersymmetry of degree one in the classical continuous version of the model. In this way, quantum chains endowed with a recursive structure can be identified from the properties of their classical relatives. The authors also show that in the quantum continuous limits of the XYZ model, the ladder property of the boost operator disappears. For the Hubbard model they demonstrate the nonexistence of a ladder operator. Nevertheless, the general structure of the conserved charges is indicated, and the expression for the terms linear in the model's free parameter for all charges is derived in closed form. 62 refs., 4 figs

  20. The spin structure of the deuteron

    International Nuclear Information System (INIS)

    Frois, B.

    1993-01-01

    The SMC collaboration has measured for the first time the spin-dependent structure function g 1 d of the deuteron in the deep inelastic scattering of polarized muons on polarized deuterons. The first moment is smaller than the prediction of the Ellis-Jaffe sum rules. It was found that the fraction of the nucleon spin carried by strange quarks Δs is appreciable and negative. Using earlier measurements of g 1 p , the first moment of the spin-dependent neutron structure function g 1 n is calculated. The combined analysis of all the available data on the spin-dependent structure functions of the nucleon shows an excellent agreement among the data sets. No significant deviations from the prediction of the Bjorken sum-rule has been found. (author) 52 refs., 19 figs., 2 tabs

  1. Ladder Safety Live #12985

    Energy Technology Data Exchange (ETDEWEB)

    Chochoms, Michael [Los Alamos National Laboratory

    2017-02-23

    This course presents information for working safely with portable ladders: specifically, stepladders, extensions ladders, and their derivations. Additionally, this course provides limited information on the safe use of stepstools and fixed ladders. The skills, techniques, and good practices needed for selecting, inspecting, setting up and securing, and using ladders are presented in this course.

  2. The spin structure of the nucleon

    International Nuclear Information System (INIS)

    Deur, A.

    2008-02-01

    This document describes the recent experimental results on the spin structure of the nucleon obtained with the electron accelerator Thomas Jefferson National Facility (Jefferson Lab), Virginia. We first discuss the goal of studying the nucleon spin structure and give the basis and phenomenology of high energy lepton scattering. Then, we discuss with some details a few sum rules concerning the spin structure of the nucleon. Those are important tools for studying the nucleon spin structure at Jefferson Lab. We then describe the present experimental situation and analyze the results. We have been able to determine an effective coupling constant for the strong interaction for any regime of quantum chromodynamics which proves that QCD is an approximately conformal theory. We conclude on the perspectives for this field of research, in particular with the 12 GeV energy upgrade of Jefferson Lab. The top priority will be the measurement of generalised parton distributions. The only issue that will stay misunderstood is the role of the very low x domain on the spin structure of the nucleon

  3. Spin structure in high energy processes: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    DePorcel, L.; Dunwoodie, C. [eds.

    1994-12-01

    This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z{sup 0}s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ({sup 3}HE) and the Bjoerken sum rule; a consumer`s guide to lattice QCD results; top ten models constrained by b {yields} sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere.

  4. Spin structure in high energy processes: Proceedings

    International Nuclear Information System (INIS)

    DePorcel, L.; Dunwoodie, C.

    1994-12-01

    This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z 0 s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ( 3 HE) and the Bjoerken sum rule; a consumer's guide to lattice QCD results; top ten models constrained by b → sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere

  5. The spin structure of the deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Frois, B. [DAPNIA/SPHN, Gif-sur-Yvette (France)

    1994-12-01

    The Spin Muon Collaboration (SMC) has measured for the first time the spin-dependent structure function g{sub 1}{sup d} of the deuteron in the deep inelastic scattering of polarized muons on polarized deuterons in the kinematic range Q{sup 2} > 1 GeV{sup 2}, 0.006 < x < 0.6. The first moment {Gamma}{sub 1}{sup d} = {integral}{sub 0}{sup 1}g{sub 1}{sup d}dx = 0.023 {+-} 0.020(stat.) {+-} 0.015(syst.) is smaller than the prediction of the Ellis-Jaffe sum rules. The author finds that the fraction of the nucleon spin carried by strange quarks {Delta}s is appreciable and negative. Using earlier measurements of g{sub 1}{sup p}, the group can infer the first moment of the spin-dependent neutron structure function g{sub 1}{sup n}. The combined analysis of all the available data on the spin-dependent structure functions of the nucleon shows an excellent agreement among the data sets. The author does not find significant deviations from the prediction of the Bjorken sum rule.

  6. Nuclear structure of Ra at high spin

    Indian Academy of Sciences (India)

    However, nuclear structure at high spin and excitation energies (∼ 6 MeV) would require a coupling of excited 1p–1h with 208Pb core. The coupling between single- particle orbitals and collective vibrations of core complicates the simple shell model picture. With increasing neutron number, Ra isotopes show an abrupt ...

  7. Unique Reversible Crystal-to-Crystal Phase Transition – Structural and Functional Properties of Fused Ladder Thienoarenes

    KAUST Repository

    Abe, Yuichiro

    2017-08-15

    Donor-acceptor type molecules based on fused ladder thienoarenes, indacenodithiophene (IDT) and dithienocyclopenta-thienothiophene (DTCTT), coupled with benzothiadiazole, are prepared and their solid-state structures are investigated. They display a rich variety of solid phases ranging from amorphous glass states to crystalline states, upon changes in the central aromatic core and side group structures. Most notably, the DTCTT-based derivatives showed reversible crystal-to-crystal phase transitions in heating and cooling cycles. Unlike what has been seen in π−conjugated molecules variable temperature XRD revealed that structural change occurs continuously during the transition. A columnar self-assembled structure with slip-stacked π−π interaction is proposed to be involved in the solid-state. This research provides the evidence of unique structural behavior of the DTCTT-based molecules through the detailed structural analysis. This unique structural transition paves the way for these materials to have self-healing of crystal defects, leading to improved optoelectronic properties.

  8. Structural features of the modulated BiCu.sub.2./sub.(P.sub.1-x./sub.V.sub.x./sub.)O.sub.6./sub. solid solution; 4-D treatment of x=0.87 compound and magnetic spin-gap to gapless transition in new Cu .sup.2+./sup. two-leg ladder systems

    Czech Academy of Sciences Publication Activity Database

    Mentré, O.; Ketatni, El M.; Colmont, M.; Huvé, M.; Abraham, F.; Petříček, Václav

    2006-01-01

    Roč. 128, - (2006), s. 10857-10867 ISSN 0002-7863 R&D Projects: GA ČR GA202/03/0430 Institutional research plan: CEZ:AV0Z10100521 Keywords : crystal-structure * bismuth * oxyphosphate * vanadate Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.696, year: 2006

  9. Spin Transport in Nondegenerate Si with a Spin MOSFET Structure at Room Temperature

    Science.gov (United States)

    Sasaki, Tomoyuki; Ando, Yuichiro; Kameno, Makoto; Tahara, Takayuki; Koike, Hayato; Oikawa, Tohru; Suzuki, Toshio; Shiraishi, Masashi

    2014-09-01

    Spin transport in nondegenerate semiconductors is expected to pave the way to the creation of spin transistors, spin logic devices, and reconfigurable logic circuits, because room-temperature (RT) spin transport in Si has already been achieved. However, RT spin transport has been limited to degenerate Si, which makes it difficult to produce spin-based signals because a gate electric field cannot be used to manipulate such signals. Here, we report the experimental demonstration of spin transport in nondegenerate Si with a spin metal-oxide-semiconductor field-effect transistor (MOSFET) structure. We successfully observe the modulation of the Hanle-type spin-precession signals, which is a characteristic spin dynamics in nondegenerate semiconductors. We obtain long spin transport of more than 20 μm and spin rotation greater than 4π at RT. We also observe gate-induced modulation of spin-transport signals at RT. The modulation of the spin diffusion length as a function of a gate voltage is successfully observed, which we attribute to the Elliott-Yafet spin relaxation mechanism. These achievements are expected to lead to the creation of practical Si-based spin MOSFETs.

  10. High-spin structure of 104Pd

    Science.gov (United States)

    Sohler, D.; Kuti, I.; Timár, J.; Joshi, P.; Molnár, J.; Paul, E. S.; Starosta, K.; Wadsworth, R.; Algora, A.; Bednarczyk, P.; Curien, D.; Dombrádi, Zs.; Duchene, G.; Fossan, D. B.; Gál, J.; Gizon, A.; Gizon, J.; Jenkins, D. G.; Juhász, K.; Kalinka, G.; Koike, T.; Krasznahorkay, A.; Nyakó, B. M.; Raddon, P. M.; Rainovski, G.; Scheurer, J. N.; Simons, A. J.; Vaman, C.; Wilkinson, A. R.; Zolnai, L.

    2012-04-01

    The high-spin structure of the nucleus 104Pd was studied through the 96Zr(13C,5n) reaction at incident energies of 51 and 58 MeV, using the Euroball IV γ-ray spectrometer in conjunction with the DIAMANT charged-particle array. Several new medium- and high-spin bands were revealed. The already known positive-parity yrast and the negative-parity cascades were extended up to Ex˜13, ˜11, and ˜9 MeV with Iπ=(26+), Iπ=(23-), and (20-), respectively. The deduced band structures were compared with Woods-Saxon total Routhian surface (TRS) calculations. In addition, non-yrast low-lying positive-parity bands were identified, which were assigned to soft γ-vibrational excitations.

  11. 46 CFR 72.05-20 - Stairways, ladders, and elevators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Stairways, ladders, and elevators. 72.05-20 Section 72... CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 72.05-20 Stairways, ladders, and elevators. (a)(1..., ladders, and elevators within main machinery spaces or cargo holds are not covered by the general...

  12. Spin structure of nucleon in QCD: inclusive and exclusive processes

    International Nuclear Information System (INIS)

    Teryaev, O.V.

    2001-01-01

    There are two basically independent ways to describe the nucleon spin structure. One is related to quark and gluon spins and another one to their total angular momenta. The latter spin structure may be studied, in principle, in hard exclusive processes

  13. High-spin structure in 40K

    Science.gov (United States)

    Söderström, P.-A.; Recchia, F.; Nyberg, J.; Gadea, A.; Lenzi, S. M.; Poves, A.; Ataç, A.; Aydin, S.; Bazzacco, D.; Bednarczyk, P.; Bellato, M.; Birkenbach, B.; Bortolato, D.; Boston, A. J.; Boston, H. C.; Bruyneel, B.; Bucurescu, D.; Calore, E.; Cederwall, B.; Charles, L.; Chavas, J.; Colosimo, S.; Crespi, F. C. L.; Cullen, D. M.; de Angelis, G.; Désesquelles, P.; Dosme, N.; Duchêne, G.; Eberth, J.; Farnea, E.; Filmer, F.; Görgen, A.; Gottardo, A.; Grębosz, J.; Gulmini, M.; Hess, H.; Hughes, T. A.; Jaworski, G.; Jolie, J.; Joshi, P.; Judson, D. S.; Jungclaus, A.; Karkour, N.; Karolak, M.; Kempley, R. S.; Khaplanov, A.; Korten, W.; Ljungvall, J.; Lunardi, S.; Maj, A.; Maron, G.; Męczyński, W.; Menegazzo, R.; Mengoni, D.; Michelagnoli, C.; Molini, P.; Napoli, D. R.; Nolan, P. J.; Norman, M.; Obertelli, A.; Podolyak, Zs.; Pullia, A.; Quintana, B.; Redon, N.; Regan, P. H.; Reiter, P.; Robinson, A. P.; Şahin, E.; Simpson, J.; Salsac, M. D.; Smith, J. F.; Stézowski, O.; Theisen, Ch.; Tonev, D.; Unsworth, C.; Ur, C. A.; Valiente-Dobón, J. J.; Wiens, A.

    2012-11-01

    High-spin states of 40K have been populated in the fusion-evaporation reaction 12C(30Si,np)40K and studied by means of γ-ray spectroscopy techniques using one triple-cluster detector of the Advanced Gamma Tracking Array at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. Several states with excitation energy up to 8 MeV and spin up to 10- have been discovered. These states are discussed in terms of J=3 and T=0 neutron-proton hole pairs. Shell-model calculations in a large model space have shown good agreement with the experimental data for most of the energy levels. The evolution of the structure of this nucleus is here studied as a function of excitation energy and angular momentum.

  14. Estimation of Structure-Borne Noise Reduction Effect of Steel Railway Bridge Equipped with Floating Ladder Track and Floating Reinforced-Concrete Deck

    Science.gov (United States)

    Watanabe, Tsutomu; Sogabe, Masamichi; Asanuma, Kiyoshi; Wakui, Hajime

    A number of steel railway bridges have been constructed in Japan. Thin steel members used for the bridges easily tend to vibrate and generate structure-borne noise. Accordingly, the number of constructions of steel railway bridges tends to decrease in the urban areas from a viewpoint of environmental preservation. Then, as a countermeasure against structure-borne noise generated from steel railway bridges, we have developed a new type of the steel railway bridge equipped with a floating-ladder track and a floating reinforced-concrete (RC) deck. As a result of train-running experiment, it became apparent that the new steel railway bridge installed by double floating system has reduced a vibration velocity level by 10.5 dB(A) at main girder web as compared with a steel railway bridge installed by directly fastened track. This reduction effect was achieved by the ladder track and RC deck supported by resilient materials.

  15. Spin excitation in granular structures with ferromagnetic nanoparticles

    CERN Document Server

    Lutsev, L V

    2002-01-01

    In terms of s-d-exchange model one studied spin excitations and relaxation in granular structures with metallic ferromagnetic nanoparticles in an insulating amorphous matrix. One studies spins of granule as a d-system; s-system represents a multitude of localized electrons of amorphous matrix. In terms of single-ring approximation on the basis of s-d-exchange interaction for the Green spin function expansion one determined spectrum of spin excitations composed of spin-wave excitations of granules and spin-polarization excitations. One studied spin-polarization relaxation occurring by way of spin-polarization excitations. Spin-polarization relaxation was determined to be efficient one within wide range of frequencies. Evaluations made for structures containing cobalt granules show that one should observe it in the centimeter, the millimeter and the submillimeter ranges of wavelength

  16. Vibration dependence of the tensor spin-spin and scalar spin-spin hyperfine interactions by precision measurement of hyperfine structures of 127I2 near 532 nm

    International Nuclear Information System (INIS)

    Hong Fenglei; Zhang Yun; Ishikawa, Jun; Onae, Atsushi; Matsumoto, Hirokazu

    2002-01-01

    Hyperfine structures of the R(87)33-0, R(145)37-0, and P(132)36-0 transitions of molecular iodine near 532 nm are measured by observing the heterodyne beat-note signal of two I 2 -stabilized lasers, whose frequencies are bridged by an optical frequency comb generator. The measured hyperfine splittings are fit to a four-term Hamiltonian, which includes the electric quadrupole, spin-rotation, tensor spin-spin, and scalar spin-spin interactions, with an accuracy of ∼720 Hz. High-accurate hyperfine constants are obtained from this fit. Vibration dependences of the tensor spin-spin and scalar spin-spin hyperfine constants are determined for molecular iodine, for the first time to our knowledge. The observed hyperfine transitions are good optical frequency references in the 532-nm region

  17. Magnetic structure of the spin valve interface

    International Nuclear Information System (INIS)

    Nicholson, D.M.C.; Butler, W.H.; Zhang, X.; MacLaren, J.M.; Gurney, B.A.; Speriosu, V.S.

    1994-01-01

    Nonferromagnetic atoms present at Ni/Cu and Permalloy/Cu interfaces in sputtered spin valve magnetoresistive layered structures have been shown to cause reduced magnetoresistance. Here we show that a model in which the moments on the Ni atoms in the interfacial region of Ni/Cu are reduced substantially by interdiffusion with Cu is consistent with the experimental results. In contrast, we believe that moments persist at the permalloy/Cu interface, which first principle total energy calculations suggest will be disordered at finite temperatures. These reduced or disordered moments are expected to significantly reduce the GMR

  18. MIT bag model and the spin structure of the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Afsar (Manchester Univ. (UK). Dept. of Theoretical Physics)

    1989-07-01

    The expressions for the total probabilities of the u and d quarks to have spins parallel or antiparallel to the spin of the parent proton are obtained in the MIT bag model. These are then used to study the spin structure of the nucleon. (author).

  19. Microfluidic serial dilution ladder.

    Science.gov (United States)

    Ahrar, Siavash; Hwang, Michelle; Duncan, Philip N; Hui, Elliot E

    2014-01-07

    Serial dilution is a fundamental procedure that is common to a large number of laboratory protocols. Automation of serial dilution is thus a valuable component for lab-on-a-chip systems. While a handful of different microfluidic strategies for serial dilution have been reported, approaches based on continuous flow mixing inherently consume larger amounts of sample volume and chip real estate. We employ valve-driven circulatory mixing to address these issues and also introduce a novel device structure to store each stage of the dilution process. The dilution strategy is based on sequentially mixing the rungs of a ladder structure. We demonstrate a 7-stage series of 1 : 1 dilutions with R(2) equal to 0.995 in an active device area of 1 cm(2).

  20. Temperature dependent spin structures in Hexaferrite crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Y.C. [Center for Condensed Matter Sciences, National Taiwan University, Taipei 106, Taiwan (China); Lin, J.G., E-mail: jglin@ntu.edu.tw [Center for Condensed Matter Sciences, National Taiwan University, Taipei 106, Taiwan (China); Chun, S.H.; Kim, K.H. [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2016-01-01

    In this work, the Hexaferrite Ba{sub 0.5}Sr{sub 1.5}Zn{sub 2}Fe{sub 12}O{sub 22} (BSZFO) is studied due to its interesting characteristics of long-wavelength spin structure. Ferromagnetic resonance (FMR) is used to probe the magnetic states of BSZFO single crystal and its temperature dependence behavior is analyzed by decomposing the multiple lines of FMR spectra into various phases. Distinguished phase transition is observed at 110 K for one line, which is assigned to the ferro(ferri)-magnetic transition from non-collinear to collinear spin state. - Highlights: • For the first time Ferromagnetic Resonance is used to probe the local magnetic structure of Ba{sub 0.5}Sr{sub 1.5}Zn{sub 2}Fe{sub 12}O{sub 22.} • The multiphases in the single crystal is identified, which provides important information toward its future application for the magnetoelectric devices.

  1. Structure of spin-dependent scattering amplitude and spin effects at small angles at RHIC energies

    International Nuclear Information System (INIS)

    Akchurin, N.; Goloskokov, S.V.; Selyugin, O.V.

    1997-01-01

    Spin-dependent pomeron effects are analyzed for elastic pp-scattering and calculations for spin-dependent differential cross sections, analyzing power and double-spin correlation parameters are carried out for the energy range of the Relativistic Heavy Ion Collider (RHIC) at BNL. In this energy range, 50 ≤√≤500 GeV, the structure of pomeron-proton coupling can be measured at RHIC with colliding polarized proton beams

  2. Structure and spin of the nucleon

    Directory of Open Access Journals (Sweden)

    Avakian H.

    2014-03-01

    Great progress has been made since then in measurements of different Single Spin Asymmetries (SSAs in semi-inclusive and hard exclusive processes providing access to TMDs and GPDs, respectively. Facilities world-wide involved in studies of the 3D structure of nucleon include HERMES, COMPASS, BELLE, BaBar, Halls A, B, and C at JLab, and PHENIX and STAR at RHIC (BNL. TMD studies in the Drell-Yan process are also becoming an important part of the program of hadron scattering experiments. Studies of TMDs are also among the main driving forces of the JLab 12-GeV upgrade project, several of the forward upgrade proposals of STAR and PHENIX at RHIC, and future facilities, such as the Electron Ion Collider (EIC, FAIR in Germany, and NICA in Russia. In this contribution we present an overview of the latest developments in studies of parton distributions and discuss newly released results, ongoing activities, as well as some future measurements.

  3. Frustrated quantum magnetism in the Kondo lattice on the zigzag ladder

    Science.gov (United States)

    Peschke, Matthias; Rausch, Roman; Potthoff, Michael

    2018-03-01

    The interplay between the Kondo effect, indirect magnetic interaction, and geometrical frustration is studied in the Kondo lattice on the one-dimensional zigzag ladder. Using the density-matrix renormalization group, the ground-state and various short- and long-range spin- and density-correlation functions are calculated for the model at half filling as a function of the antiferromagnetic Kondo interaction down to J =0.3 t , where t is the nearest-neighbor hopping on the zigzag ladder. Geometrical frustration is shown to lead to at least two critical points: Starting from the strong-J limit, where almost local Kondo screening dominates and where the system is a nonmagnetic Kondo insulator, antiferromagnetic correlations between nearest-neighbor and next-nearest-neighbor local spins become stronger and stronger, until at Jcdim≈0.89 t frustration is alleviated by a spontaneous breaking of translational symmetry and a corresponding transition to a dimerized state. This is characterized by antiferromagnetic correlations along the legs and by alternating antiferro- and ferromagnetic correlations on the rungs of the ladder. A mechanism of partial Kondo screening that has been suggested for the Kondo lattice on the two-dimensional triangular lattice is not realized in the one-dimensional case. Furthermore, within the symmetry-broken dimerized state, there is a magnetic transition to a 90∘ quantum spin spiral with quasi-long-range order at Jcmag≈0.84 t . The quantum-critical point is characterized by a closure of the spin gap (with decreasing J ) and a divergence of the spin-correlation length and of the spin-structure factor S (q ) at wave vector q =π /2 . This is opposed to the model on the one-dimensional bipartite chain, which is known to have a finite spin gap for all J >0 at half filling.

  4. Effects of spin-orbit coupling on the spin structure of deposited transition-metal clusters

    Science.gov (United States)

    Mankovsky, S.; Bornemann, S.; Minár, J.; Polesya, S.; Ebert, H.; Staunton, J. B.; Lichtenstein, A. I.

    2009-07-01

    The influence of the spin-orbit coupling on the magnetic structure of deposited transition-metal nanostructures has been studied by fully relativistic electronic-structure calculations. The interplay of exchange coupling and magnetic anisotropy was monitored by studying the corresponding magnetic torque calculated within ab initio and model approaches. We find that a spin-orbit-induced Dzyaloshinski-Moriya interaction has a profound effect on the spin structure of such complex magnetic systems and that in combination with magnetic anisotropies and isotropic exchange this can result in peculiar magnetic properties.

  5. Ladder attachment platform

    Science.gov (United States)

    Swygert,; Richard, W [Springfield, SC

    2012-08-28

    A ladder attachment platform is provided that includes a base for attachment to a ladder that has first and second side rails and a plurality of rungs that extend between in a lateral direction. Also included is a user platform for having a user stand thereon that is carried by the base. The user platform may be positioned with respect to the ladder so that it is not located between a first plane that extends through the first side rail and is perpendicular to the lateral direction and a second plane that extends through the second side rail and is perpendicular to the lateral direction.

  6. Spin structure of the nucleon and triangle anomaly

    International Nuclear Information System (INIS)

    Efremov, A.V.; Teryaev, O.V.

    1988-01-01

    It is shown that the gluon contribution to the sum rule for spin parton distribution functions which determines the spin of the nucleon is fixed by the axial Adler-Bell-Jackiw anomaly. The new sum rule is consistent with OCD evolution equations and predicts that quarks carry about 70% of the nucleon spin. The gluon contribution results in negative extra term to the Ellis-Jaffe sum rule for the structure function g 1 which accounts for its disagreement with experiment

  7. Boat boarding ladder placement

    Science.gov (United States)

    1998-04-01

    Presented in three volumes; 'Boat Boarding Ladder Placement,' which explores safety considerations including potential for human contact with a rotating propeller; 'Boat Handhold Placement,' which explores essential principles and methods of fall con...

  8. Effect of spin polarization on the structural properties and bond ...

    Indian Academy of Sciences (India)

    coupled to semi-empirical hardness theory proved effective in hardness prediction for the metal borides which agree well with the experimental values. These results would help to gain insight into the spin-polarized effect on the structural and bond hardness. Keywords. Iron boride; DFT; spin polarized; critical pressure; ...

  9. The spin structure of the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Le Goff, J.M

    2005-02-15

    The nucleon is a spin 1/2 particle. This spin can be decomposed into the contributions of its constituents: 1/2 equals 1/2*{delta}{sigma} + {delta}g + L{sub q} + L{sub g} where the first term is the contribution from the spin of the quarks, the second term is the contribution from the spin of the gluons and L{sub q} and L{sub g} are the orbital momentum of the quark and the gluon respectively. The {delta}{sigma} contribution of the spin of quarks can be studied through polarized deep inelastic scattering (DIS). We introduce DIS and the so-called parton model and then turn to the case of polarized DIS in the inclusive and semi-inclusive cases. We also discuss how a third parton distribution, called transversity, appears together with the unpolarized and the longitudinally polarized (or helicity) ones. We show how the longitudinally polarized gluon distribution can be measured. Then we focus on the SMC and COMPASS experiments performed at CERN. SMC confirmed a previous result by showing that the contribution of the spin of the quark to the spin of the nucleon was small. SMC also performed a measurement on the deuterium in order to test, for the first time, the Bjorker sum rules, which is a fundamental prediction of quantum chromodynamics. The COMPASS experiment started collecting data in 2002. Its main objectives are the gluon polarization {delta}g/g and the so-called transversity. (A.C.)

  10. Dimers on Surface Graphs and Spin Structures. I

    DEFF Research Database (Denmark)

    Cimasoni, David; Reshetikhin, Nicolai

    2007-01-01

    Partition functions for dimers on closed oriented surfaces are known to be alternating sums of Pfaffians of Kasteleyn matrices. In this paper, we obtain the formula for the coefficients in terms of discrete spin structures....

  11. Temperature dependence of the magnetization of canted spin structures

    DEFF Research Database (Denmark)

    Jacobsen, Henrik; Lefmann, Kim; Brok, Erik

    2012-01-01

    Numerous studies of the low-temperature saturation magnetization of ferrimagnetic nanoparticles and diamagnetically substituted ferrites have shown an anomalous temperature dependence. It has been suggested that this is related to freezing of canted magnetic structures. We present models...... for the temperature dependence of the magnetization of a simple canted spin structure in which relaxation can take place at finite temperatures between spin configurations with different canting angles. We show that the saturation magnetization may either decrease or increase with decreasing temperature, depending...

  12. 29 CFR 1917.119 - Portable ladders.

    Science.gov (United States)

    2010-07-01

    ... Requirements for Portable Reinforced Plastic Ladders (d) Standards for job-made portable ladders. Job-made... usage. (1) Ladders made by fastening rungs or devices across a single rail are prohibited. (2) Ladders...

  13. A Career Ladder's Effect on Teacher Career and Work Attitudes.

    Science.gov (United States)

    Hart, Ann Weaver

    1987-01-01

    A career ladder affecting the work structure and career opportunities of teachers was studied to determine effects on teacher attitudes. Responses of 389 elementary through high school teachers to career ladder work efforts, work of schools, peer supervision, and career growth opportunities and stability were affected by the design. (TJH)

  14. Masses, magnetic moments, QCD and proton spin structure

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1990-10-01

    This talk is dedicated to the memory of Andrei D. Sakharov. In addition to his well-known contributions to society, Sakharov was also a pioneer in spin physics and the application of the basic ideas of QCD to spin structure of hadrons. He took quarks seriously at the time when the particle physicists ridiculed the quark model. Immediately after the quark proposal Sakharov asked: 'Why is M Λ ≠ M Σ ? They contain the same quarks' His answer was 'Spin Physics! A flavor-dependent hyperfine interaction'. (author)

  15. Pure spin current injection in hydrogenated graphene structures

    Science.gov (United States)

    Zapata-Peña, Reinaldo; Mendoza, Bernardo S.; Shkrebtii, Anatoli I.

    2017-11-01

    We present a theoretical study of spin-velocity injection (SVI) of a pure spin current (PSC) induced by linearly polarized light that impinges normally on the surface of two 50% hydrogenated noncentrosymmetric two-dimensional (2D) graphene structures. The first structure, labeled Up and also known as graphone, is hydrogenated only on one side, and the second, labeled Alt, is 25% hydrogenated at both sides. The hydrogenation opens an energy gap on both structures. The PSC formalism has been developed in the length gauge perturbing Hamiltonian, and includes, through the single-particle density matrix, the excited coherent superposition of the spin-split conduction bands inherent to the noncentrosymmetric nature of the structures considered in this work. We analyze two possibilities: in the first, the spin is fixed along a chosen direction, and the resulting SVI is calculated; in the second, we choose the SVI direction along the surface plane, and calculate the resulting spin orientation. This is done by changing the energy ℏ ω and polarization angle α of the incoming light. The results are calculated within a full electronic band structure scheme using the density functional theory (DFT) in the local density approximation (LDA). The maxima of the spin velocities are reached when ℏ ω =0.084 eV and α =35∘ for the Up structure, and ℏ ω =0.720 eV and α =150∘ for the Alt geometry. We find a speed of 668 and 645 km/s for the Up and the Alt structures, respectively, when the spin points perpendicularly to the surface. Also, the response is maximized by fixing the spin-velocity direction along a high-symmetry axis, obtaining a speed of 688 km/s with the spin pointing at 13∘ from the surface normal, for the Up, and 906 km/s and the spin pointing at 60∘ from the surface normal, for the Alt system. These speed values are orders of magnitude larger than those of bulk semiconductors, such as CdSe and GaAs, thus making the hydrogenated graphene structures

  16. Proton spin structure study with PHENIX detector at RHIC

    International Nuclear Information System (INIS)

    Bazilevsky, A.

    2000-01-01

    Acceleration of polarized protons in Relativistic Heavy Ion Collider (RHIC) will provide unique tool to study spin structure of the nucleon, covering the √s region from 50 GeV to 500 GeV with proton polarization of 70%. PHENIX, one of the major detector systems at RHIC, is going to investigate poorly known gluon and flavor identified sea quark polarization in the proton. Overview of the RHENIX spin program is presented and sensitivities of the measurements are discussed

  17. Effect of spin polarization on the structural properties and bond ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 39; Issue 6. Effect of spin ... Volume 39 Issue 6 October 2016 pp 1427-1434 ... Spin-polarization calculations show that ferromagnetic state (FM) is stable for FexB structures and carry magnetic moment of 1.12, 1.83 and 2.03 μ B inFeB, Fe 2 B and Fe 3 B, respectively.

  18. The latrine ownership ladder

    DEFF Research Database (Denmark)

    Obeng, Peter Appiah; Keraita, Bernard; Oduro-Kwarteng, Sampson

    2015-01-01

    Purpose – The purpose of this paper is to present the latrine ownership ladder as a conceptual policy framework to enhance sanitation uptake in low-income peri-urban areas. Design/methodology/approach – The paper draws from literature and a case study in a Ghanaian peri-urban community to highlig...

  19. Corrosion Control Specialist Career Ladder AFSC 53530, 53550, 53570, and 53690. Occupational Survey Report.

    Science.gov (United States)

    Air Force Occupational Measurement Center, Lackland AFB, TX.

    The report describes the results of a detailed occupational survey of the corrosion control career ladder. Responses to a 457-task, time rating inventory from 1,015 personnel (representing 64 percent of the career field) were analyzed to produce seven specific findings and the career ladder structure. The career ladder includes a variety of jobs…

  20. Triptycene-based ladder monomers and polymers, methods of making each, and methods of use

    KAUST Repository

    Pinnau, Ingo

    2015-02-05

    Embodiments of the present disclosure provide for a triptycene-based A-B monomer, a method of making a triptycene-based A-B monomer, a triptycene-based ladder polymer, a method of making a triptycene-based ladder polymers, a method of using triptycene-based ladder polymers, a structure incorporating triptycene-based ladder polymers, a method of gas separation, and the like.

  1. Magnetic coupling and spin structure in nanocrystalline iron powders

    International Nuclear Information System (INIS)

    Slawska-Waniewska, A; Grafoute, M; Greneche, J M

    2006-01-01

    Pure single-phase iron nanostructured particles with pseudo-cubic shape crystalline grains and linear dimensions of around 11 nm can be produced by the low energy ball milling of microcrystalline Fe under argon atmosphere. The long range ferromagnetic correlation of exchange coupled crystallites extending across grain boundaries leads to a reduction of the effective anisotropy, as expected from the generalized random anisotropy model. This ferromagnetic network of correlated grains is preserved at low temperatures. No spin-glass freezing process is detected. Slight oxidation of the particles with formation of an FeO phase is achieved with deliberately prolonged milling. This FeO phase leads to non-collinear spin structure at the interfaces that suppresses the intergrain correlations and enhances the role of long range dipolar interactions. The interface spin disorder and the complex state of the intergrain interactions are the sources of the spin-glass-like behaviour found in these Fe-FeO nanocomposites

  2. Temperature dependence of the magnetization of canted spin structures

    International Nuclear Information System (INIS)

    Jacobsen, Henrik; Lefmann, Kim; Brok, Erik; Frandsen, Cathrine; Mørup, Steen

    2012-01-01

    Numerous studies of the low-temperature saturation magnetization of ferrimagnetic nanoparticles and diamagnetically substituted ferrites have shown an anomalous temperature dependence. It has been suggested that this is related to freezing of canted magnetic structures. We present models for the temperature dependence of the magnetization of a simple canted spin structure in which relaxation can take place at finite temperatures between spin configurations with different canting angles. We show that the saturation magnetization may either decrease or increase with decreasing temperature, depending on the ratio of the exchange coupling constants. This is in agreement with experimental observations. - Highlights: ► The magnetization of a canted spin structure has been calculated. ► In some cases the magnetization shows an anomalous increase at low temperatures. ► In other cases the magnetization shows an anomalous decrease at low temperatures. ► The results are in accordance with many experimental observations.

  3. Spin Echo Attenuation of Restricted Diffusion as a Discord of Spin Phase Structure

    Science.gov (United States)

    Stepišnik, Janez

    1998-04-01

    By using the particle probability density we analyze the spin echo attenuation of particles, diffusing in a bounded region. It provides a means to expand a nonuniform spin phase distribution into a series of waves that characterize the geometry and boundary conditions of confinement. Random motion disrupts the initial phase structure created by applied gradients and consequently discords its structure waves. By assuming the spin phase fluctuation and/or the randomness of spin phase distribution in the subensemble as a Gaussian stochastic process, we derive a new analytical expression for the echo attenuation related to the particle velocity correlation. For a diffusion in porous structure we get the expression featuring the same "diffusive diffraction" patterns as those being found and explained by P. T. Callaghan and A. Coy ("Principles of Nuclear Magnetic Resonance Microscopy," Oxford Univ. Press, Oxford (1991);J. Chem. Phys.101, 4599-4609 (1994)) with the use of propagator theory. With the new approach we cast a new light on the phenomena and derive analitically how the diffusive diffractions appear when the sequence of finite or even modulated gradients are applied. The method takes into account the non-Markovian character of restricted diffusion, and therefore the echo dependence on the diffusion lengths and on the strength of applied gradient differs from the results of authors assuming the Markovian diffusion either by dealing with the diffusion propagators or by the computer simulation of Fick's diffusion.

  4. Quark-hadron duality of nucleon spin structure function

    International Nuclear Information System (INIS)

    Dong, Y.B.

    2005-01-01

    Bloom-Gilman quark-hadron duality of nuclear spin structure function is studied by comparing the integral of g 1 from perturbative QCD prediction in the scaling region to the moment of g 1 in the resonance region. The spin structure function in the resonance region is estimated by the parametrization forms of non-resonance background and of resonance contributions. The uncertainties of our calculations due to those parametrization forms are discussed. Moreover, the effect of the Δ(1232)-resonance in the first resonance region and the role of the resonances in the second resonance region are explicitly shown. Elastic peak contribution to the duality is also analyzed. (orig.)

  5. A balanced intervention ladder: promoting autonomy through public health action.

    Science.gov (United States)

    Griffiths, P E; West, C

    2015-08-01

    The widely cited Nuffield Council on Bioethics 'Intervention Ladder' structurally embodies the assumption that personal autonomy is maximized by non-intervention. Consequently, the Intervention Ladder encourages an extreme 'negative liberty' view of autonomy. Yet there are several alternative accounts of autonomy that are both arguably superior as accounts of autonomy and better suited to the issues facing public health ethics. We propose to replace the one-sided ladder, which has any intervention coming at a cost to autonomy, with a two-sided 'Balanced Intervention Ladder,' where intervention can either enhance or diminish autonomy. We show that not only the alternative, richer accounts of autonomy but even Mill's classic version of negative liberty puts some interventions on the positive side of the ladder. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  6. Ladder Variational Autoencoder

    DEFF Research Database (Denmark)

    Sønderby, Casper Kaae; Raiko, Tapani; Maaløe, Lars

    2016-01-01

    Variational autoencoders are powerful models for unsupervised learning. However deep models with several layers of dependent stochastic variables are difficult to train which limits the improvements obtained using these highly expressive models. We propose a new inference model, the Ladder...... Variational Autoencoder, that recursively corrects the generative distribution by a data dependent approximate likelihood in a process resembling the recently proposed Ladder Network. We show that this model provides state of the art predictive log-likelihood and tighter log-likelihood lower bound compared...... to the purely bottom-up inference in layered Variational Autoencoders and other generative models. We provide a detailed analysis of the learned hierarchical latent representation and show that our new inference model is qualitatively different and utilizes a deeper more distributed hierarchy of latent...

  7. Ladder variational autoencoders

    DEFF Research Database (Denmark)

    Sønderby, Casper Kaae; Raiko, Tapani; Maaløe, Lars

    2016-01-01

    Variational autoencoders are powerful models for unsupervised learning. However deep models with several layers of dependent stochastic variables are difficult to train which limits the improvements obtained using these highly expressive models. We propose a new inference model, the Ladder...... Variational Autoencoder, that recursively corrects the generative distribution by a data dependent approximate likelihood in a process resembling the recently proposed Ladder Network. We show that this model provides state of the art predictive log-likelihood and tighter log-likelihood lower bound compared...... to the purely bottom-up inference in layered Variational Autoencoders and other generative models. We provide a detailed analysis of the learned hierarchical latent representation and show that our new inference model is qualitatively different and utilizes a deeper more distributed hierarchy of latent...

  8. The Spin Structure of the Proton in the Resonance Region

    Energy Technology Data Exchange (ETDEWEB)

    Fatemi, Renee H. [Univ. of Virginia, Charlottesville, VA (United States)

    2002-01-01

    Inclusive double spin asymmetries have been measured for $\\vec{p}$($\\vec{e}$,e') using the CLAS detector and a polarized 15NH3 target at Jefferson Lab in 1998. The virtual photon asymmetry A1, the longitudinal spin structure function, g1 (x, Q2), and the first moment Γ$1\\atop{p}$, have been extracted for a Q2 range of 0.15-2.0 GeV2. These results provide insight into the low Q2 evolution of spin dependent asymmetries and structure functions as well as the transition of Γ$1\\atop{p}$ from the photon point, where the Gerasimov, Drell and Hearn Sum Rule is expected to be satisfied, to the deep inelastic region.

  9. Ladder Structures and Magnetic Surveys: New Insights into the Near Surface, Three-Dimensional Shape and Orientation of Plutonic Structures in the Tuolumne Intrusive Suite, Yosemite National Park, California

    Science.gov (United States)

    Boyd, J. D.

    2017-12-01

    The study of pluton emplacement and growth history offers a window into the evolution of the continental crust. Plutons, however, are often largely homogeneous in outcrop, lacking reliable structural markers for tracking their emplacement and growth through time. The ladder structures exposed on the glacially polished surfaces of the Tuolumne Intrusive Suite (TIS) in Yosemite National Park, California are an exception. Ladder structures (LS) are eye-catching concentrations of alternating mafic and felsic mineral assemblages in dominantly cresent-shaped, meter to sub-meter scale bands in outcrop that locally terminate into a mafic band forming a circular-shaped enclosure. Their geochemistry and modal mineralogy diverge sharply from host rock trends with large quantities of magnetite, titanite, and zircon in the mafic assemblages. The limited exposure of LS in outcrops has led to much debate as to their true geometries and orientations. The high concentration of magnetite in the LS is fortuitous in that it allows these features to be investigated by magnetic techniques. The preliminary results of new high resolution magnetic surveys of these LS are presented here. A grid of total magnetic intensity (TMI) was collected across the ladder structures. The TMI's were then inverted and modeled to determine the orientation of the magnetic bodies with depth using PyGMI freeware. With sufficient contrast in the magnetic susceptibility (Km) between the feature being imaged and the host rock, meter to sub-meter scale features can be resolved. The average Km of the LS mafic bands and the host rock is approximately 200-850 x10-3 and 15-20×10-3 SI units respectively. These measurements along with oriented samples were collected to determine input parameters (e.g. anisotropy and remanence) for the geocellular model used in this study.

  10. Micro-nanofibers with hierarchical structure by bubbfil-spinning

    Directory of Open Access Journals (Sweden)

    Liu Peng

    2015-01-01

    Full Text Available Bubbfil spinning is used to fabricate micro/nanofibers with hierarchical structure. The wall of a polymer film is attenuated unevenly by a blowing air. The burst of the bubble results in film fragments with different thickness, as a result, different sizes of fibers are obtained.

  11. High-spin structure of neutron-rich Dy isotopes

    Indian Academy of Sciences (India)

    Abstract. In view of recent experimental progress on production and spectroscopy of neutron-rich isotopes of Dy with mass number A. 166 and 168, we have made theoretical investigations on the structure of high spin states of164 170Dy isotopes in the cranked Hartree–Fock–Bogoliubov (CHFB) theory employing a ...

  12. Spin structure of the nucleon and the constituent quark model

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Afsar

    1989-05-01

    It is shown that the constituent quark model is capable of giving a consistent description of the integrated spin-dependent structure function of the nucleon. This enables us to perceive an intrinsic connection between the current and the constituent pictures of the quark. (author).

  13. Nuclear structure at high spin using multidetector gamma array and ...

    Indian Academy of Sciences (India)

    2014-04-05

    Apr 5, 2014 ... Nuclear structure at high spin. Figure 1. Schematic of the orientation of HPGe detector in GDA [4]. These signals were fed to custom-made data acquisition system Freedom [10] which was later used for data reduction. We recorded γ-ray fold of nuclear reaction using multiplicity filter made of BGO scin-.

  14. Spin transport in lateral structures with semiconducting channel

    Science.gov (United States)

    Zainuddin, Abu Naser

    Spintronics is an emerging field of electronics with the potential to be used in future integrated circuits. Spintronic devices are already making their mark in storage technologies in recent times and there are proposals for using spintronic effects in logic technologies as well. So far, major improvement in spintronic effects, for example, the `spin-valve' effect, is being achieved in metals or insulators as channel materials. But not much progress is made in semiconductors owing to the difficulty in injecting spins into them, which has only very recently been overcome with the combined efforts of many research groups around the world. The key motivations for semiconductor spintronics are their ease in integration with the existing semiconductor technology along with the gate controllability. At present semiconductor based spintronic devices are mostly lateral and are showing a very poor performance compared to their metal or insulator based vertical counterparts. The objective of this thesis is to analyze these devices based on spin-transport models and simulations. At first a lateral spin-valve device is modeled with the spin-diffusion equation based semiclassical approach. Identifying the important issues regarding the device performance, a compact circuit equivalent model is presented which would help to improve the device design. It is found that the regions outside the current path also have a significant influence on the device performance under certain conditions, which is ordinarily neglected when only charge transport is considered. Next, a modified spin-valve structure is studied where the spin signal is controlled with a gate in between the injecting and detecting contacts. The gate is used to modulate the rashba spin-orbit coupling of the channel which, in turn, modulates the spin-valve signal. The idea of gate controlled spin manipulation was originally proposed by Datta and Das back in 1990 and is called 'Datta-Das' effect. In this thesis, we have

  15. Level Structure of 103Ag at high spins

    OpenAIRE

    Ray, S.; Pattabiraman, N. S.; Krishichayan; Chakraborty, A.; Mukhopadhyay, S.; Ghugre, S. S.; Chintalapudi, S. N.; Sinha, A. K.; Garg, U.; Zhu, S.; Kharraja, B.; Almehed, D.

    2007-01-01

    High spin states in $^{103}$Ag were investigated with the Gammasphere array, using the $^{72}$Ge($^{35}$Cl,$2p2n$)$^{103}$Ag reaction at an incident beam energy of 135 MeV. A $\\Delta J$=1 sequence with predominantly magnetic transitions and two nearly-degenerate $\\Delta J=1$ doublet bands have been observed. The dipole band shows a decreasing trend in the $B(M1)$ strength as function of spin, a well established feature of magnetic bands. The nearly-degenerate band structures satisfy the three...

  16. Spin Hamiltonian effective parameters from periodic electronic structure calculations

    International Nuclear Information System (INIS)

    Rivero, P; Moreira, I de Pr; Illas, F

    2008-01-01

    This paper presents and discusses a general procedure to extract spin Hamiltonian effective parameters from periodic calculations. The methodology is illustrated through representative examples of increasing complexity covering systems with three dimensional magnetic order or with a two dimensional magnetic structure. Some more complex systems are discussed where physical intuition based on the crystal structure of the system does not provide a reliable guide but where the present approach can be applied in a straightforward way

  17. Towards Unifying Structures in Higher Spin Gauge Symmetry

    Directory of Open Access Journals (Sweden)

    Anders K.H. Bengtsson

    2008-02-01

    Full Text Available This article is expository in nature, outlining some of the many still incompletely understood features of higher spin field theory. We are mainly considering higher spin gauge fields in their own right as free-standing theoretical constructs and not circumstances where they occur as part of another system. Considering the problem of introducing interactions among higher spin gauge fields, there has historically been two broad avenues of approach. One approach entails gauging a non-Abelian global symmetry algebra, in the process making it local. The other approach entails deforming an already local but Abelian gauge algebra, in the process making it non-Abelian. In cases where both avenues have been explored, such as for spin 1 and 2 gauge fields, the results agree (barring conceptual and technical issues with Yang-Mills theory and Einstein gravity. In the case of an infinite tower of higher spin gauge fields, the first approach has been thoroughly developed and explored by M. Vasiliev, whereas the second approach, after having lain dormant for a long time, has received new attention by several authors lately. In the present paper we briefly review some aspects of the history of higher spin gauge fields as a backdrop to an attempt at comparing the gauging vs. deforming approaches. A common unifying structure of strongly homotopy Lie algebras underlying both approaches will be discussed. The modern deformation approach, using BRST-BV methods, will be described as far as it is developed at the present time. The first steps of a formulation in the categorical language of operads will be outlined. A few aspects of the subject that seems not to have been thoroughly investigated are pointed out.

  18. Dimers on surface graphs and spin structures. II

    DEFF Research Database (Denmark)

    Cimasoni, David; Reshetikhin, Nicolai

    2009-01-01

    In a previous paper [3], we showed how certain orientations of the edges of a graph Γ embedded in a closed oriented surface Σ can be understood as discrete spin structures on Σ. We then used this correspondence to give a geometric proof of the Pfaffian formula for the partition function of the di......In a previous paper [3], we showed how certain orientations of the edges of a graph Γ embedded in a closed oriented surface Σ can be understood as discrete spin structures on Σ. We then used this correspondence to give a geometric proof of the Pfaffian formula for the partition function...... model as a quantum field theory on surface graphs....

  19. High-spin structure of yrast-band in Kr

    Indian Academy of Sciences (India)

    pp. 185–189. High-spin structure of yrast-band in. 78. Kr. P K JOSHI, R PALIT, H C JAIN, S NAGARAJ and J A SHEIKH. Tata Institute of Fundamental Research, Mumbai 400 005, India. Abstract. Lifetime of levels up to 22. ·. , have been measured in Kr and an oblate shape is assigned to the ground state using the CSM and ...

  20. Topological spin-singlet superconductors with underlying sublattice structure

    Science.gov (United States)

    Dutreix, C.

    2017-07-01

    Majorana boundary quasiparticles may naturally emerge in a spin-singlet superconductor with Rashba spin-orbit interactions when a Zeeman magnetic field breaks time-reversal symmetry. Their existence and robustness against adiabatic changes is deeply related, via a bulk-edge correspondence, to topological properties of the band structure. The present paper shows that the spin-orbit may be responsible for topological transitions when the superconducting system has an underlying sublattice structure, as it appears in a dimerized Peierls chain, graphene, and phosphorene. These systems, which belong to the Bogoliubov-de Gennes class D, are found to have an extra symmetry that plays the role of the parity. It enables the characterization of the topology of the particle-hole symmetric band structure in terms of band inversions. The topological phase diagrams this leads to are then obtained analytically and exactly. They reveal that, because of the underlying sublattice structure, the existence of topological superconducting phases requires a minimum doping fixed by the strength of the Rashba spin orbit. Majorana boundary quasiparticles are finally predicted to emerge when the Fermi level lies in the vicinity of the bottom (top) of the conduction (valence) band in semiconductors such as the dimerized Peierls chain and phosphorene. In a two-dimensional topological superconductor based on (stretched) graphene, which is semimetallic, Majorana quasiparticles cannot emerge at zero and low doping, that is, when the Fermi level is close to the Dirac points. Nevertheless, they are likely to appear in the vicinity of the van Hove singularities.

  1. 29 CFR 1926.1053 - Ladders.

    Science.gov (United States)

    2010-07-01

    ... plastic ladder shall sustain at least 3.3 times the maximum intended load. The ability of a ladder to... that each extra-heavy-duty type 1A metal or plastic ladders shall sustain at least 3.3 times the... from anticipated usage of the ladder, shall also be included), plus anticipated loads caused by ice...

  2. Fractional vortex lattice structures in spin-triplet superconductors

    International Nuclear Information System (INIS)

    Chung, Suk Bum; Agterberg, Daniel F; Kim, Eun-A

    2009-01-01

    Motivated by recent interest in spin-triplet superconductors, we investigate the vortex lattice structures for this class of unconventional superconductors. We discuss how the order parameter symmetry can give rise to U(1)xU(1) symmetry in the same sense as in spinor condensates, making half-quantum vortices (HQVs) topologically stable. We then calculate the vortex lattice structure of HQVs, with particular attention on the roles of the crystalline lattice, the Zeeman coupling and Meissner screening, all absent in spinor condensates. Finally, we consider how spin-orbit coupling leads to a breakdown of the U(1)xU(1) symmetry in free energy and whether the HQV lattice survives this symmetry breaking. As examples, we examine simpler spin-triplet models proposed in the context of Na x CoO 2 ·yH 2 O and Bechgaard salts, as well as the better known and more complex model for Sr 2 RuO 4 .

  3. The impact of structural relaxation on spin polarization and magnetization reversal of individual nano structures studied by spin-polarized scanning tunneling microscopy.

    Science.gov (United States)

    Sander, Dirk; Phark, Soo-Hyon; Corbetta, Marco; Fischer, Jeison A; Oka, Hirofumi; Kirschner, Jürgen

    2014-10-01

    The application of low temperature spin-polarized scanning tunneling microscopy and spectroscopy in magnetic fields for the quantitative characterization of spin polarization, magnetization reversal and magnetic anisotropy of individual nano structures is reviewed. We find that structural relaxation, spin polarization and magnetic anisotropy vary on the nm scale near the border of a bilayer Co island on Cu(1 1 1). This relaxation is lifted by perimetric decoration with Fe. We discuss the role of spatial variations of the spin-dependent electronic properties within and at the edge of a single nano structure for its magnetic properties.

  4. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Gap Caused by Strong Pairing in the Ladder Model of DNA Molecules

    Science.gov (United States)

    Hu, Dong-Sheng; Zhu, Chen-Ping; Zhang, Long-Qiang; He, Da-Ren; Wang, Bing-Hong

    2008-05-01

    By directly diagonalizing the Hamiltonian of the ladder model of deoxyribonucleic acid (DNA) molecules, the density of states is obtained. It is found that DNA behaves as a conductor when the interchain hopping is smaller than twice the intrachain one, otherwise, DNA behaves as a semiconductor.

  5. Measuring spin-dependent structure functions at CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, A. [Universitaet Frankfurt (Germany)

    1994-04-01

    The author analyses whether CEBAF with a 10 GeV beam could contribute significantly to the understanding of spin-dependent deep-inelastic scattering as well as semi-inclusive reactions. The main advantage of CEBAF is the much better attainable statistics, its great disadvantage its comparably low energy, which limits the accessible x-range to about 0.15 to 0.7. Within these constraints CEBAF could provide (1) high precision data which would be very valuable to understand the Q{sup 2} dependence of the spin-dependent structure functions g{sub 1}(x) and G{sub 2}(x) and (2) the by far most precise determination of the third moments of g{sub 1}(x) and g{sub 2}(x) the latter of which the author argues to be related to a fundamental property of the nucleon.

  6. Pressure-induced superconductivity in the iron-based ladder material BaFe2S3.

    Science.gov (United States)

    Takahashi, Hiroki; Sugimoto, Akira; Nambu, Yusuke; Yamauchi, Touru; Hirata, Yasuyuki; Kawakami, Takateru; Avdeev, Maxim; Matsubayashi, Kazuyuki; Du, Fei; Kawashima, Chizuru; Soeda, Hideto; Nakano, Satoshi; Uwatoko, Yoshiya; Ueda, Yutaka; Sato, Taku J; Ohgushi, Kenya

    2015-10-01

    All the iron-based superconductors identified so far share a square lattice composed of Fe atoms as a common feature, despite having different crystal structures. In copper-based materials, the superconducting phase emerges not only in square-lattice structures but also in ladder structures. Yet iron-based superconductors without a square-lattice motif have not been found, despite being actively sought out. Here, we report the discovery of pressure-induced superconductivity in the iron-based spin-ladder material BaFe2S3, a Mott insulator with striped-type magnetic ordering below ∼120 K. On the application of pressure this compound exhibits a metal-insulator transition at about 11 GPa, followed by the appearance of superconductivity below Tc = 14 K, right after the onset of the metallic phase. Our findings indicate that iron-based ladder compounds represent promising material platforms, in particular for studying the fundamentals of iron-based superconductivity.

  7. Precision measurement of the neutron spin dependent structure functions

    International Nuclear Information System (INIS)

    Kolomensky, Y.G.

    1997-02-01

    In experiment E154 at the Stanford Linear Accelerator Center the spin dependent structure function g 1 n (x, Q 2 ) of the neutron was measured by scattering longitudinally polarized 48.3 GeV electrons off a longitudinally polarized 3 He target. The high beam energy allowed the author to extend the kinematic coverage compared to the previous SLAC experiments to 0.014 ≤ x ≤ 0.7 with an average Q 2 of 5 GeV 2 . The author reports the integral of the spin dependent structure function in the measured range to be ∫ 0.014 0.7 dx g 1 n (x, 5 GeV 2 ) = -0.036 ± 0.004(stat.) ± 0.005(syst.). The author observes relatively large values of g 1 n at low x that call into question the reliability of data extrapolation to x → 0. Such divergent behavior disagrees with predictions of the conventional Regge theory, but is qualitatively explained by perturbative QCD. The author performs a Next-to-Leading Order perturbative QCD analysis of the world data on the nucleon spin dependent structure functions g 1 p and g 1 n paying careful attention to the experimental and theoretical uncertainties. Using the parameterizations of the helicity-dependent parton distributions obtained in the analysis, the author evolves the data to Q 2 = 5 GeV 2 , determines the first moments of the polarized structure functions of the proton and neutron, and finds agreement with the Bjorken sum rule

  8. Precision measurement of the neutron spin dependent structure functions

    Energy Technology Data Exchange (ETDEWEB)

    Kolomensky, Y.G.

    1997-02-01

    In experiment E154 at the Stanford Linear Accelerator Center the spin dependent structure function g{sub 1}{sup n} (x, Q{sup 2}) of the neutron was measured by scattering longitudinally polarized 48.3 GeV electrons off a longitudinally polarized {sup 3}He target. The high beam energy allowed the author to extend the kinematic coverage compared to the previous SLAC experiments to 0.014 {le} x {le} 0.7 with an average Q{sup 2} of 5 GeV{sup 2}. The author reports the integral of the spin dependent structure function in the measured range to be {integral}{sub 0.014}{sup 0.7} dx g{sub 1}{sup n}(x, 5 GeV{sup 2}) = {minus}0.036 {+-} 0.004(stat.) {+-} 0.005(syst.). The author observes relatively large values of g{sub 1}{sup n} at low x that call into question the reliability of data extrapolation to x {r_arrow} 0. Such divergent behavior disagrees with predictions of the conventional Regge theory, but is qualitatively explained by perturbative QCD. The author performs a Next-to-Leading Order perturbative QCD analysis of the world data on the nucleon spin dependent structure functions g{sub 1}{sup p} and g{sub 1}{sup n} paying careful attention to the experimental and theoretical uncertainties. Using the parameterizations of the helicity-dependent parton distributions obtained in the analysis, the author evolves the data to Q{sup 2} = 5 GeV{sup 2}, determines the first moments of the polarized structure functions of the proton and neutron, and finds agreement with the Bjorken sum rule.

  9. Vortex Flipping in Superconductor-Ferromagnet Spin Valve Structures

    Science.gov (United States)

    Patino, Edgar J.; Aprili, Marco; Blamire, Mark; Maeno, Yoshiteru

    2014-03-01

    We report in plane magnetization measurements on Ni/Nb/Ni/CoO and Co/Nb/Co/CoO spin valve structures with one of the ferromagnetic layers pinned by an antiferromagnetic layer. In samples with Ni, below the superconducting transition Tc, our results show strong evidence of vortex flipping driven by the ferromagnets magnetization. This is a direct consequence of proximity effect that leads to vortex supercurrents leakage into the ferromagnets. Here the polarized electron spins are subject to vortices magnetic field occasioning vortex flipping. Such novel mechanism has been made possible for the first time by fabrication of the F/S/F/AF multilayered spin valves with a thin-enough S layer to barely confine vortices inside as well as thin-enough F layers to align and control the magnetization within the plane. When Co is used there is no observation of vortex flipping effect. This is attributed to Co shorter coherence length. Interestingly instead a reduction in pinning field of about 400 Oe is observed when the Nb layer is in superconducting state. This effect cannot be explained in terms of vortex fields. In view of these facts any explanation must be directly related to proximity effect and thus a remarkable phenomenon that deserves further investigation. Programa Nacional de Ciencias Basicas COLCIENCIAS (No. 120452128168).

  10. Anatomy of a Spin: The Information-Theoretic Structure of Classical Spin Systems

    Directory of Open Access Journals (Sweden)

    Vikram S. Vijayaraghavan

    2017-05-01

    Full Text Available Collective organization in matter plays a significant role in its expressed physical properties. Typically, it is detected via an order parameter, appropriately defined for each given system’s observed emergent patterns. Recent developments in information theory, however, suggest quantifying collective organization in a system- and phenomenon-agnostic way: decomposing the system’s thermodynamic entropy density into a localized entropy, that is solely contained in the dynamics at a single location, and a bound entropy, that is stored in space as domains, clusters, excitations, or other emergent structures. As a concrete demonstration, we compute this decomposition and related quantities explicitly for the nearest-neighbor Ising model on the 1D chain, on the Bethe lattice with coordination number k = 3 , and on the 2D square lattice, illustrating its generality and the functional insights it gives near and away from phase transitions. In particular, we consider the roles that different spin motifs play (in cluster bulk, cluster edges, and the like and how these affect the dependencies between spins.

  11. Efficient spin transfer phenomena in Fe/MgO/GaAs structure.

    Science.gov (United States)

    Park, Y J; Hickey, M C; Van Veenhuizen, M J; Chang, J; Heiman, D; Perry, C H; Moodera, J S

    2011-03-23

    The efficiency of spin polarized charge transfer was investigated in an Fe/MgO tunnel barrier/GaAs based structure using spin dependent photocurrent measurements, whereby a spin imbalance in carrier population was generated in the GaAs by circularly polarized light. The dominance of tunneling transport processes over Schottky emission gave rise to a high spin transfer efficiency of 35% under the photovoltaic mode of device operation. A spin dependent tunneling conductance associated with spin polarized electron transport was identified by the observation of phase changes. This transport prevails over the unpolarized electron and hole conduction over the bias range which corresponds to flat band conditions.

  12. Experimental verification of the rotational type of chiral spin spiral structures by spin-polarized scanning tunneling microscopy.

    Science.gov (United States)

    Haze, Masahiro; Yoshida, Yasuo; Hasegawa, Yukio

    2017-10-16

    We report on experimental verification of the rotational type of chiral spin spirals in Mn thin films on a W(110) substrate using spin-polarized scanning tunneling microscopy (SP-STM) with a double-axis superconducting vector magnet. From SP-STM images using Fe-coated W tips magnetized to the out-of-plane and [001] directions, we found that both Mn mono- and double-layers exhibit cycloidal rotation whose spins rotate in the planes normal to the propagating directions. Our results agree with the theoretical prediction based on the symmetry of the system, supporting that the magnetic structures are driven by the interfacial Dzyaloshinskii-Moriya interaction.

  13. Model for ballistic spin-transport in ferromagnet/two-dimensional electron gas/ferromagnet structures

    NARCIS (Netherlands)

    Schapers, T; Nitta, J; Heersche, HB; Takayanagi, H

    The spin dependent conductance of a ferromagnet/two-dimensional electron gas ferromagnet structure is theoretically examined in the ballistic transport regime. It is shown that the spin signal can be improved considerably by making use of the spin filtering effect of a barrier at the ferromagnet

  14. A sum rule for the spin-dependent structure function b1(x) for spin-one hadrons

    International Nuclear Information System (INIS)

    Close, F.E.

    1990-05-01

    We show that the spin-dependent structure function of spin-one hadrons, b 1 (x), is related to the electric quadrupole moment of the target and obtain ∫ dx b 1 (x) = lim t→0 - 5/3 t/4M 2 F q (t) = 0 for isoscalar targets if the sea of quarks and antiquarks is unpolarised. We show how this sum rule is modified in the presence of a polarised sea. (author)

  15. Nuclear structure of 94,95Mo at high spins

    International Nuclear Information System (INIS)

    Kharraja, B.; Ghugre, S.S.; Garg, U.; Janssens, R.V.; Carpenter, M.P.; Crowell, B.; Khoo, T.L.; Lauritsen, T.; Nisius, D.; Reviol, W.; Mueller, W.F.; Riedinger, L.L.; Kaczarowski, R.

    1998-01-01

    The high-spin level structures of 94,95 Mo (N=52,53) have been investigated via the 65 Cu( 36 S, αp2n) 94 Mo and 65 Cu( 36 S, αpn) 95 Mo reactions at 142 MeV. The level schemes have been extended up to spin J∼19ℎ and excitation energies E x ∼12 MeV. Spherical shell-model calculations have been performed and compared with the experimental energy levels. The level structure of 94 Mo exhibits a single-particle nature and the higher-angular-momentum states are dominated by the excitation of a g 9/2 neutron across the N=50 shell gap. The level sequences observed in 95 Mo have been interpreted on the basis of the spherical shell model and weak coupling of a d 5/2 or a g 7/2 neutron to the 94 Mo core. copyright 1998 The American Physical Society

  16. Magnetic precursor of the pressure-induced superconductivity in Fe-ladder compound

    Science.gov (United States)

    Chi, Songxue; Uwatoko, Yoshiya; Cao, Huibo; Hirata, Yasuyuki; Hashizume, Kazuki; Aoyama, Takuya; Ohgushi, Kenya

    The pressure effects on the antiferromagentic orders in iron-based ladder compounds CsFe2Se3 and BaFe2S3 have been studied using neutron diffraction. With identical crystal structure and similar magnetic structures, the two compounds exhibit highly contrasting magnetic behaviors under moderate external pressures. In CsFe2Se3 the ladders are brought much closer to each other by pressure, but the stripe-type magnetic order shows no observable change. In contrast, the stripe order in BaFe2S3, undergoes a quantum phase transition where an abrupt increase of N e xel temperature by more than 50% occurs at about 1 GPa, accompanied by a jump in the ordered moment. With its spin structure unchanged, BaFe2S3 enters an enhanced magnetic phase that bears the characteristics of an orbital selective Mott phase, which is the true neighbor of superconductivity emerging at higher pressures. Research at Oak Ridge National Laboratorys HFIR was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.This work was supported by JSPS KAKENHI Grant Number 16H04019.

  17. Spin-frustrated V3 and Cu3 nanomagnets with Dzialoshinsky-Moriya exchange. 2. Spin structure, spin chirality and tunneling gaps

    International Nuclear Information System (INIS)

    Belinsky, Moisey I.

    2009-01-01

    The spin chirality and spin structure of the Cu 3 and V 3 nanomagnets with the Dzialoshinsky-Moriya (DM) exchange interaction are analyzed. The correlations between the vector κ and the scalar χ chirality are obtained. The DM interaction forms the spin chirality which is equal to zero in the Heisenberg clusters. The dependences of the spin chirality on magnetic field and deformations are calculated. The cluster distortions reduce the spin chirality. The vector chirality is reduced partially and the scalar chirality vanishes in the transverse magnetic field. In the isosceles clusters, the DM exchange and distortions determine the sign and degree of the spin chirality κ. The correlations between the chirality parameters κ n and the intensities of the EPR and INS transitions are obtained. The vector chirality κ n describes the spin chirality of the Cu 3 and V 3 nanomagnets, the scalar chirality describes the pseudoorbital moment of the DM cluster. It is shown that in the consideration of the DM exchange, the spin states DM mixing and tunneling gaps at level crossing fields depend on the coordinate system of the DM model. The calculations in the DM exchange models in the right-handed and left-handed frame show opposite magnetic behavior at the level crossing field and allow to explain the opposite schemes of the tunneling gaps and levels crossing, which have been obtained in different treatments. The results of the DM model in the right-handed frame are consistent with the results of the group-theoretical analysis, whereas the results in the left-handed frame are inconsistent with that. The correlations between the spin chirality of the ground state and tunneling gaps at the level crossing field are obtained for the equilateral and isosceles nanoclusters.

  18. Quasi spin pairing and the structure of the Lipkin model

    International Nuclear Information System (INIS)

    Cambiaggio, M.C.; Plastino, A.

    1978-01-01

    By introducing the concepts of quasi-spin pairing and quasi-spin seniority, the Lipkin model is extended to a variable number of particles. The properties of quasi-spin pairing are seen to be quite similar to those of ordinary pairing. The quasi-spin seniority allows one to obtain a simple classification of excited multiplets. A 'pairing plus monopole' model is studied in connection with the Hartree-Fock theory. (orig.) [de

  19. The Role of Coulomb Interactions for Spin Crossover Behaviors and Crystal Structural Transformation in Novel Anionic Fe(III Complexes from a π-Extended ONO Ligand

    Directory of Open Access Journals (Sweden)

    Suguru Murata

    2016-05-01

    Full Text Available To investigate the π-extension effect on an unusual negative-charged spin crossover (SCO FeIII complex with a weak N2O4 first coordination sphere, we designed and synthesized a series of anionic FeIII complexes from a π-extended naphthalene derivative ligand. Acetonitrile-solvate tetramethylammonium (TMA salt 1 exhibited an SCO conversion, while acetone-solvate TMA salt 2 was in a high-spin state. The crystal structural analysis for 2 revealed that two-leg ladder-like cation-anion arrays derived from π-stacking interactions between π-ligands of the FeIII complex anion and Coulomb interactions were found and the solvated acetone molecules were in one-dimensional channels between the cation-anion arrays. A desolvation-induced single-crystal-to-single-crystal transformation to desolvate compound 2’ may be driven by Coulomb energy gain. Furthermore, the structural comparison between quasi-polymorphic compounds 1 and 2 revealed that the synergy between Coulomb and π-stacking interactions induces a significant distortion of coordination structure of 2.

  20. Global symplectic structure-preserving integrators for spinning compact binaries

    Science.gov (United States)

    Zhong, Shuang-Ying; Wu, Xin; Liu, San-Qiu; Deng, Xin-Fa

    2010-12-01

    This paper deals mainly with the application of the second-order symplectic implicit midpoint rule and its symmetric compositions to a post-Newtonian Hamiltonian formulation with canonical spin variables in relativistic compact binaries. The midpoint rule, as a basic algorithm, is directly used to integrate the completely canonical Hamiltonian system. On the other hand, there are symmetric composite methods based on a splitting of the Hamiltonian into two parts: the Newtonian part associated with a Kepler motion, and a perturbation part involving the orbital post-Newtonian and spin contributions, where the Kepler flow has an analytic solution and the perturbation can be calculated by the midpoint rule. An example is the second-order mixed leapfrog symplectic integrator with one stage integration of the perturbation flow and two semistage computations of the Kepler flow at every integration step. Also, higher-order composite methods such as the Forest-Ruth fourth-order symplectic integrator and its optimized algorithm are applicable. Various numerical tests including simulations of chaotic orbits show that the mixed leapfrog integrator is always superior to the midpoint rule in energy accuracy, while both of them are almost equivalent in computational efficiency. Particularly, the optimized fourth-order algorithm compared with the mixed leapfrog scheme provides good precision and needs no expensive additional computational time. As a result, it is worth performing a more detailed and careful examination of the dynamical structure of chaos and order in the parameter windows and phase space of the binary system.

  1. A Determination of the Neutron Spin Structure Function

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Emlyn W

    2003-08-18

    The authors report the results of the experiment E142 which measured the spin dependent structure function of the neutron, g{sub 1}{sup n}(x, Q{sup 2}). The experiment was carried out at the Stanford Linear Accelerator Center by measuring an asymmetry in the deep inelastic scattering of polarized electrons from a polarized {sup 3}He target, at electron energies from 19 to 26 GeV. The structure function was determined over the kinematic range 0.03 < BJorken x < 0.6 and 1.0 < Q{sup 2} < 5.5 (GeV/c){sup 2}. An evaluation of the integral {integral}{sub 0}{sup 1} g{sub 1}{sup n}(x,Q{sup 2})dx at fixed Q{sup 2} = 2 (GeV/c){sup 2} yields the final result {Lambda}{sub 1}{sup n} = -0.032 {+-} 0.006 (stat.) {+-} 0.009 (syst.). This result, when combined with the integral of the proton spin structure function measured in other experiments, confirms the fundamental Bjorken sum rule with O({alpha}{sub s}{sup 3}) corrections to within one standard deviation. This is a major success for perturbative Quantum Chromodynamics. Some ancillary results include the findings that the Ellis-Jaffe sum rule for the neutron is violated at the 2 {sigma} level, and that the total contribution of the quarks to the helicity of the nucleon is 0.36 {+-} 0.10. The strange sea polarization is estimated to be small and negative, {Delta}s = -0.07 {+-} 0.04.

  2. Surface induces different crystal structures in a room temperature switchable spin crossover compound.

    Science.gov (United States)

    Gentili, Denis; Liscio, Fabiola; Demitri, Nicola; Schäfer, Bernhard; Borgatti, Francesco; Torelli, Piero; Gobaut, Benoit; Panaccione, Giancarlo; Rossi, Giorgio; Degli Esposti, Alessandra; Gazzano, Massimo; Milita, Silvia; Bergenti, Ilaria; Ruani, Giampiero; Šalitroš, Ivan; Ruben, Mario; Cavallini, Massimiliano

    2016-01-07

    We investigated the influence of surfaces in the formation of different crystal structures of a spin crossover compound, namely [Fe(L)2] (LH: (2-(pyrazol-1-yl)-6-(1H-tetrazol-5-yl)pyridine), which is a neutral compound thermally switchable around room temperature. We observed that the surface induces the formation of two different crystal structures, which exhibit opposite spin transitions, i.e. on heating them up to the transition temperature, one polymorph switches from high spin to low spin and the second polymorph switches irreversibly from low spin to high spin. We attributed this inversion to the presence of water molecules H-bonded to the complex tetrazolyl moieties in the crystals. Thin deposits were investigated by means of polarized optical microscopy, atomic force microscopy, X-ray diffraction, X-ray absorption spectroscopy and micro Raman spectroscopy; moreover the analysis of the Raman spectra and the interpretation of spin inversion were supported by DFT calculations.

  3. The search for competing charge orders in frustrated ladder systems

    International Nuclear Information System (INIS)

    Lal, Siddhartha; Laad, Mukul S.

    2007-08-01

    A recent study revealed the dynamics of the charge sector of a one-dimensional quarter- filled electronic system with extended Hubbard interactions to be that of an effective pseudospin transverse-field Ising model (TFIM) in the strong coupling limit. With the twin motivations of studying the co-existing charge and spin order found in strongly correlated chain systems and the effects of inter-chain couplings, we investigate the phase diagram of coupled effective (TFIM) systems. A bosonisation and RG analysis for a two-leg TFIM ladder yields a rich phase diagram showing Wigner/Peierls charge order and Neel/dimer spin order. In a broad parameter regime, the orbital antiferromagnetic phase is found to be stable. An intermediate gapless phase of finite width is found to lie in between two charge-ordered gapped phases. Kosterlitz-Thouless transitions are found to lead from the gapless phase to either of the charge-ordered phases. Low energy effective Hamiltonian analyses of a strongly coupled 2-chain ladder system confirm a phase diagram with in-chain CO, rung-dimer, and orbital antiferromagnetic ordered phases with varying interchain couplings as well as superconductivity upon hole-doping. Our work is potentially relevant for a unified description of a class of strongly correlated, quarter-filled chain and ladder systems. (autor)

  4. Electronic structure of the two-legged ladder compound La 1-xSr xCuO 2.5

    Science.gov (United States)

    Mattheiss, L. F.

    1996-03-01

    The band properties of La 1-xSr xCuO 2.5, an orthorhombic cuprate that contains a pair of nearly orthogonal two-legged ladders and undergoes an insulator-metal transition near x ≈ 0.2, have been calculated using the linear augmented-plane-wave method. The undoped x = 0 results feature four half-filled σ ∗ bands that exhibit anisotropic (i.e., {v∥}/{v⊥} ≈ 4 ) rather than one-dimensional (1D) characteristics near E F. A tight-binding analysis shows that, for ladders in the x-y plane, the σ ∗ bands at E F reflect a ˜50-50 O(2p)Cu(3d) admixture, with d(x 2-y 2) orbitals dominating (˜75%) the 3d fraction, but containing sufficient d(yz) - d(3z 3-r 2) hybridization (˜12%+12%) to wash out most 1D features via interladder coupling.

  5. Nuclear structure at high-spin and large-deformation

    International Nuclear Information System (INIS)

    Shimizu, Yoshifumi R.

    2000-01-01

    Atomic nucleus is a finite quantal system and shows various marvelous features. One of the purposes of the nuclear structure study is to understand such features from a microscopic viewpoint of nuclear many-body problem. Recently, it is becoming possible to explore nuclear states under 'extreme conditions', which are far different from the usual ground states of stable nuclei, and new aspects of such unstable nuclei attract our interests. In this lecture, I would like to discuss the nuclear structure in the limit of rapid rotation, or the extreme states with very large angular momenta, which became accessible by recent advent of large arrays of gamma-ray detecting system; these devices are extremely useful to measure coincident multiple γ-rays following heavy-ion fusion reactions. Including such experimental aspects as how to detect the nuclear rotational states, I review physics of high-spin states starting from the elementary subjects of nuclear structure study. In would like also to discuss the extreme states with very large nuclear deformation, which are easily realized in rapidly rotating nuclei. (author)

  6. Understanding the proton's spin structure

    Energy Technology Data Exchange (ETDEWEB)

    Myhrer, Fred [Univ. of South Carolina, Columbia, SC (United States); Thomas, Anthony W. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States)

    2010-02-01

    We discuss the tremendous progress that has been towards an understanding of how the spin of the proton is distributed on its quark and gluon constituents. This is a problem that began in earnest twenty years ago with the discovery of the proton "spin crisis" by the European Muon Collaboration. The discoveries prompted by that original work have given us unprecedented insight into the amount of spin carried by polarized gluons and the orbital angular momentum of the quarks.

  7. A Review and Modern Approach to LC Ladder Synthesis

    Directory of Open Access Journals (Sweden)

    Alexander J. Casson

    2011-01-01

    Full Text Available Ultra low power circuits require robust and reliable operation despite the unavoidable use of low currents and the weak inversion transistor operation region. For analogue domain filtering doubly terminated LC ladder based filter topologies are thus highly desirable as they have very low sensitivities to component values: non-exact component values have a minimal effect on the realised transfer function. However, not all transfer functions are suitable for implementation via a LC ladder prototype, and even when the transfer function is suitable the synthesis procedure is not trivial. The modern circuit designer can thus benefit from an updated treatment of this synthesis procedure. This paper presents a methodology for the design of doubly terminated LC ladder structures making use of the symbolic maths engines in programs such as MATLAB and MAPLE. The methodology is explained through the detailed synthesis of an example 7th order bandpass filter transfer function for use in electroencephalogram (EEG analysis.

  8. Spin structure at the partonic level. Pt. 2

    International Nuclear Information System (INIS)

    Leader, E.

    1983-01-01

    Knowledge of the spin and momentum distribution of partons inside a polarised nucleon, as deduced from lepton scattering, is combined with lowest order QCD to calculate spin dependent parameters in large psub(T) hadronic reactions. Clear predictions emerge in some cases and are in conflict with present experimental results. There is a real challenge to improve both theory and experiment. (orig.)

  9. Investigations on the local structure and the spin-Hamiltonian ...

    Indian Academy of Sciences (India)

    In the calculations, the contributions to the spin-Hamiltonian parameters from ligand orbital and spin-orbit coupling are included on the basis of the cluster approach ... Manuscript received: 23 October 2014; Manuscript revised: 23 November 2015; Accepted: 16 December 2015; Final version published online: 13 July 2016 ...

  10. The spin structure of magnetic nanoparticles and in magnetic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Disch, Sabrina

    2011-09-26

    The present thesis provides an extensive and original contribution to the investigation of magnetic nanoparticles regarding synthesis and structural characterization using advanced scattering methods in all length scales between the atomic and mesoscopic size range. Particular emphasis is on determination of the magnetic structure of single nanoparticles as well as preparation and characterization of higher dimensional assemblies thereof. The unique physical properties arising from the finite size of magnetic nanoparticles are pronounced for very small particle sizes. With the aim of preparing magnetic nanoparticles suitable for investigation of such properties, a micellar synthesis route for very small cobalt nanoparticles is explored. Cobalt nanoparticles with diameters of less than 3 nm are prepared and characterized, and routes for variation of the particle size are developed. The needs and limitations of primary characterization and handling of such small and oxidation-sensitive nanoparticles are highlighted and discussed in detail. Comprehensive structural and magnetic characterization is performed on iron oxide nanoparticles of {proportional_to} 10 nm in diameter. Particle size and narrow size distribution are determined with high precision. Investigation of the long range and local atomic structure reveals a particle size dependent magnetite - maghemite structure type with lattice distortions induced at the particle surface. The spatial magnetization distribution within these nanoparticles is determined to be constant in the particle core with a decrease towards the particle surface, thus indicating a magnetic dead layer or spin canting close to the surface. Magnetically induced arrangements of such nanoparticles into higher dimensional assemblies are investigated in solution and by deposition of long range ordered mesocrystals. Both cases reveal a strong dependence of the found structures on the nanoparticle shape (spheres, cubes, and heavily truncated

  11. Spin-related transport phenomena in HgTe-based quantum well structures

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, Markus

    2007-12-15

    Within the scope of this thesis, spin related transport phenomena have been investigated in HgTe/Hg{sub 0.3}Cd{sub 0.7}Te quantum well structures. In our experiments, the existence of the quantum spin Hall (QSH) state was successfully demonstrated for the first time and the presented results provide clear evidence for the charge transport properties of the QSH state. Our experiments provide the first direct observation of the Aharonov-Casher (AC) effect in semiconductor structures. In conclusion, HgTe quantum well structures have proven to be an excellent template for studying spin-related transport phenomena: The QSH relies on the peculiar band structure of the material and the existence of both the spin Hall effect and the AC effect is a consequence of the substantial spin-orbit interaction. (orig.)

  12. Tunable superconducting critical temperature in ballistic hybrid structures with strong spin-orbit coupling

    Science.gov (United States)

    Simensen, Haakon T.; Linder, Jacob

    2018-02-01

    We present a theoretical description and numerical simulations of the superconducting transition in hybrid structures including strong spin-orbit interactions. The spin-orbit coupling is taken to be of Rashba type for concreteness, and we allow for an arbitrary magnitude of the spin-orbit strength as well as an arbitrary thickness of the spin-orbit coupled layer. This allows us to make contact with the experimentally relevant case of enhanced interfacial spin-orbit coupling via atomically thin heavy metal layers. We consider both interfacial spin-orbit coupling induced by inversion asymmetry in an S/F junction, as well as in-plane spin-orbit coupling in the ferromagnetic region of an S/F/S and an S/F structure. Both the pair amplitudes, local density of states, and critical temperature show dependency on the Rashba strength and, importantly, the orientation of the exchange field. In general, spin-orbit coupling increases the critical temperature of a proximity system where a magnetic field is present, and enhances the superconducting gap in the density of states. We perform a theoretical derivation which explains these results by the appearance of long-ranged singlet correlations. Our results suggest that Tc in ballistic spin-orbit coupled superconducting structures may be tuned by using only a single ferromagnetic layer.

  13. Spin State as a Marker for the Structural Evolution of Nature's Water-Splitting Catalyst.

    Science.gov (United States)

    Krewald, Vera; Retegan, Marius; Neese, Frank; Lubitz, Wolfgang; Pantazis, Dimitrios A; Cox, Nicholas

    2016-01-19

    In transition-metal complexes, the geometric structure is intimately connected with the spin state arising from magnetic coupling between the paramagnetic ions. The tetramanganese-calcium cofactor that catalyzes biological water oxidation in photosystem II cycles through five catalytic intermediates, each of which adopts a specific geometric and electronic structure and is thus characterized by a specific spin state. Here, we review spin-structure correlations in Nature's water-splitting catalyst. The catalytic cycle of the Mn4O5Ca cofactor can be described in terms of spin-dependent reactivity. The lower "inactive" S states of the catalyst, S0 and S1, are characterized by low-spin ground states, SGS = 1/2 and SGS = 0. This is connected to the "open cubane" topology of the inorganic core in these states. The S2 state exhibits structural and spin heterogeneity in the form of two interconvertible isomers and is identified as the spin-switching point of the catalytic cycle. The first S2 state form is an open cubane structure with a low-spin SGS = 1/2 ground state, whereas the other represents the first appearance of a closed cubane topology in the catalytic cycle that is associated with a higher-spin ground state of SGS = 5/2. It is only this higher-spin form of the S2 state that progresses to the "activated" S3 state of the catalyst. The structure of this final metastable catalytic state was resolved in a recent report, showing that all manganese ions are six-coordinate. The magnetic coupling is dominantly ferromagnetic, leading to a high-spin ground state of SGS = 3. The ability of the Mn4O5Ca cofactor to adopt two distinct structural and spin-state forms in the S2 state is critical for water binding in the S3 state, allowing spin-state crossing from the inactive, low-spin configuration of the catalyst to the activated, high-spin configuration. Here we describe how an understanding of the magnetic properties of the catalyst in all S states has allowed conclusions on

  14. Topological Electronic Structures and Spintronics Applications for Silicene and Other Spin-Orbit Thin Films

    Science.gov (United States)

    Lin, Hsin

    2014-03-01

    While spin-orbit coupling plays a critical role in generating topologically insulating phases, it also provides a novel route for realizing spin-split states in nonmagnetic materials without the need for exchange coupling. Two-dimensional thin films with significant spin-orbit coupling strength enable potential applications for spintronics devices because the spin-splitting energy can be controlled by an external field (gating). Moreover, spin-orbit coupling can induce nontrivial topological phases, i.e. quantum spin Hall phases, which could harbor back-scattering-free spin-polarized current at the edge. Recently, we have shown via first-principles calculations that field-gated silicene possesses two gapped Dirac cones exhibiting nearly 100% spin-polarization, situated at the corners of the Brillouin zone. Band gaps as well as the band topology can be tuned with an external electric field perpendicular to the plane, which breaks the inversion symmetry of the system due to the presence of buckling in the honeycomb structure. Using this fact, we propose a design for a silicene-based spin-filter that would enable the spin-polarization of an output current to be switched electrically, without the need to switch external magnetic fields. Our quantum transport calculations indicate that the proposed designs will be highly efficient (nearly 100% spin polarization) and robust against weak disorder and edge imperfections. We also propose a Y-shaped spin/valley separator that produces spin-polarized current at two output terminals with opposite spins. Ge, Sn, and Pb counterparts of silicene are shown to have similar properties, but their larger spin-orbit coupling results in larger energy differences between the spin-split states making these materials better suited for room temperature applications. Other spin-orbit thin films will be discussed. Our investigations demonstrate that spin-orbit thin films present great potential for manipulating spin/valley degrees of freedom

  15. Anomalous magnetic structure and spin dynamics in magnetoelectric LiFePO4

    DEFF Research Database (Denmark)

    Toft-Petersen, Rasmus; Reehuis, Manfred; Jensen, Thomas Bagger Stibius

    2015-01-01

    We report significant details of the magnetic structure and spin dynamics of LiFePO4 obtained by single-crystal neutron scattering. Our results confirm a previously reported collinear rotation of the spins away from the principal b axis, and they determine that the rotation is toward the a axis...... with earlier susceptibility measurements. Using a spin Hamiltonian, we show that the spin dimensionality is intermediate between XY- and Ising-like, with an easy b axis and a hard c axis. It is shown that both next-nearest neighbor exchange couplings in the bc plane are in competition with the strongest...

  16. Imaging the real space structure of the spin fluctuations in an iron-based superconductor.

    Science.gov (United States)

    Chi, Shun; Aluru, Ramakrishna; Grothe, Stephanie; Kreisel, A; Singh, Udai Raj; Andersen, Brian M; Hardy, W N; Liang, Ruixing; Bonn, D A; Burke, S A; Wahl, Peter

    2017-06-29

    Spin fluctuations are a leading candidate for the pairing mechanism in high temperature superconductors, supported by the common appearance of a distinct resonance in the spin susceptibility across the cuprates, iron-based superconductors and many heavy fermion materials. The information we have about the spin resonance comes almost exclusively from neutron scattering. Here we demonstrate that by using low-temperature scanning tunnelling microscopy and spectroscopy we can characterize the spin resonance in real space. We show that inelastic tunnelling leads to the characteristic dip-hump feature seen in tunnelling spectra in high temperature superconductors and that this feature arises from excitations of the spin fluctuations. Spatial mapping of this feature near defects allows us to probe non-local properties of the spin susceptibility and to image its real space structure.

  17. Imaging the real space structure of the spin fluctuations in an iron-based superconductor

    Science.gov (United States)

    Chi, Shun; Aluru, Ramakrishna; Grothe, Stephanie; Kreisel, A.; Singh, Udai Raj; Andersen, Brian M.; Hardy, W. N.; Liang, Ruixing; Bonn, D. A.; Burke, S. A.; Wahl, Peter

    2017-06-01

    Spin fluctuations are a leading candidate for the pairing mechanism in high temperature superconductors, supported by the common appearance of a distinct resonance in the spin susceptibility across the cuprates, iron-based superconductors and many heavy fermion materials. The information we have about the spin resonance comes almost exclusively from neutron scattering. Here we demonstrate that by using low-temperature scanning tunnelling microscopy and spectroscopy we can characterize the spin resonance in real space. We show that inelastic tunnelling leads to the characteristic dip-hump feature seen in tunnelling spectra in high temperature superconductors and that this feature arises from excitations of the spin fluctuations. Spatial mapping of this feature near defects allows us to probe non-local properties of the spin susceptibility and to image its real space structure.

  18. The determination of the in situ structure by nuclear spin contrast variation

    International Nuclear Information System (INIS)

    Stuhrmann, H.B.; Nierhaus, K.H.

    1994-01-01

    Polarized neutron scattering from polarized nuclear spins in hydrogenous substances opens a new way of contrast variation. The enhanced contrast due to proton spin polarization was used for the in situ structure determination of tRNA of the functional complex of the E.coli ribosome

  19. Electron refrigeration in hybrid structures with spin-split superconductors

    Science.gov (United States)

    Rouco, M.; Heikkilä, T. T.; Bergeret, F. S.

    2018-01-01

    Electron tunneling between superconductors and normal metals has been used for an efficient refrigeration of electrons in the latter. Such cooling is a nonlinear effect and usually requires a large voltage. Here we study the electron cooling in heterostructures based on superconductors with a spin-splitting field coupled to normal metals via spin-filtering barriers. The cooling power shows a linear term in the applied voltage. This improves the coefficient of performance of electron refrigeration in the normal metal by shifting its optimum cooling to lower voltage, and also allows for cooling the spin-split superconductor by reverting the sign of the voltage. We also show how tunnel coupling spin-split superconductors with regular ones allows for a highly efficient refrigeration of the latter.

  20. Signatures of pairing in the magnetic excitation spectrum of strongly correlated two-leg ladders

    Science.gov (United States)

    Nocera, A.; Patel, N. D.; Dagotto, E.; Alvarez, G.

    2017-11-01

    Magnetic interactions are widely believed to play a crucial role in the microscopic mechanism leading to high critical temperature superconductivity. It is therefore important to study the signatures of pairing in the magnetic excitation spectrum of simple models known to show unconventional superconducting tendencies. Using the density matrix renormalization group technique, we calculate the dynamical spin structure factor S (k ,ω ) of a generalized t -U -J Hubbard model away from half filling in a two-leg ladder geometry. The addition of J enhances pairing tendencies. We analyze quantitatively the signatures of pairing in the magnetic excitation spectra. We found that the superconducting pair-correlation strength, that can be estimated independently from ground state properties, is closely correlated with the integrated low-energy magnetic spectral weight in the vicinity of (π ,π ) . In this wave-vector region, robust spin incommensurate features develop with increasing doping. The branch of the spectrum with rung direction wave vector krung=0 does not change substantially with doping where pairing dominates and thus plays a minor role. We discuss the implications of our results for neutron scattering experiments, where the spin excitation dynamics of hole-doped quasi-one-dimensional magnetic materials can be measured and also address implications for recent resonant inelastic x-ray scattering experiments.

  1. De optimale sportafstand voor de ladder van de glazenwasser

    NARCIS (Netherlands)

    Reijneveld, C.N.; Looze, M.P. de; Hoozemans, M.J.M.; Grinten, M.P. van der; Korte, E.M. de; Kingma, I.

    2002-01-01

    Voor de glazenwasser die werkt met staande ladder, is een goede ladder zeer belangrijk. Hij loopt en werkt op en verplaatst de ladder veelvuldig. Er is veel discussie over ladders en de optimale sportafstand bij staande ladders. De meeste glazenwassers geven de voorkeur aan een sportafstand van 35

  2. Large spin Hall magnetoresistance and its correlation to the spin-orbit torque in W/CoFeB/MgO structures

    Science.gov (United States)

    Cho, Soonha; Baek, Seung-heon Chris; Lee, Kyeong-Dong; Jo, Younghun; Park, Byong-Guk

    2015-01-01

    The phenomena based on spin-orbit interaction in heavy metal/ferromagnet/oxide structures have been investigated extensively due to their applicability to the manipulation of the magnetization direction via the in-plane current. This implies the existence of an inverse effect, in which the conductivity in such structures should depend on the magnetization orientation. In this work, we report a systematic study of the magnetoresistance (MR) of W/CoFeB/MgO structures and its correlation with the current-induced torque to the magnetization. We observe that the MR is independent of the angle between the magnetization and current direction but is determined by the relative magnetization orientation with respect to the spin direction accumulated by the spin Hall effect, for which the symmetry is identical to that of so-called the spin Hall magnetoresistance. The MR of ~1% in W/CoFeB/MgO samples is considerably larger than those in other structures of Ta/CoFeB/MgO or Pt/Co/AlOx, which indicates a larger spin Hall angle of W. Moreover, the similar W thickness dependence of the MR and the current-induced magnetization switching efficiency demonstrates that MR in a non-magnet/ferromagnet structure can be utilized to understand other closely correlated spin-orbit coupling effects such as the inverse spin Hall effect or the spin-orbit spin transfer torques. PMID:26423608

  3. Ising versus S U (2) 2 string-net ladder

    Science.gov (United States)

    Vidal, Julien

    2018-03-01

    We consider the string-net model obtained from S U (2) 2 fusion rules. These fusion rules are shared by two different sets of anyon theories. In this paper, we study the competition between the two corresponding non-Abelian quantum phases in the ladder geometry. A detailed symmetry analysis shows that the nontrivial low-energy sector corresponds to the transverse-field cluster model that displays a critical point described by the s o (2) 1 conformal field theory. Other sectors are obtained by freezing spins in this model.

  4. Spin structure measurements from E143 at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, L.M. [Stanford Univ., CA (United States)

    1997-01-01

    Measurements have been made of the proton and deuteron spin structure functions, g{sub 1}{sup p} at beam energies of 29.1, 16.2, and 9.7 GeV, and g{sub 2}{sup p} and g{sub 2}{sup d} at a beam energy of 29.1 GeV. The integrals {Gamma}{sub p} = {integral}{sub 0}{sup 1} g{sub 1}{sup p} (x, Q{sup 2})dx and {Gamma}{sub d} = {integral}{sub 0}{sup 1} g{sub 1}{sup d}(x, Q{sup 2})dx have been evaluated at fixed Q{sup 2} = 3 (GeV/c){sup 2} using the 29.1 GeV data to yield {Gamma}{sub p} = 0.127 {+-} 0.004(stat.) {+-} 0.010(syst.) and {Gamma}{sub d} = 0.041 {+-} 0.003 {+-} 0.004. The Q{sup 2} dependence of the ratio g{sub 1}/F{sub 1} has been studied and is found to be small for Q{sup 2} > 1 (GeV/c){sup 2}. Within experimental precision, the g{sub 2} data are well-described by the twist-2 contribution, g{sub 2}{sup ww}. Twist-3 matrix elements have been extracted and are compared to theoretical predictions. The asymmetry A{sub 2} has also been measured and is found to be significantly smaller than the positivity limit {radical}R for both targets A{sub 2}{sup p} is found to be positive and inconsistent with zero.

  5. Sum rule measurements of the spin-dependent compton amplitude (nucleon spin structure at Q2 = 0)

    International Nuclear Information System (INIS)

    Babusci, D.; Giordano, G.; Baghaei, H.; Cichocki, A.; Blecher, M.; Breuer, M.; Commeaux, C.; Didelez, J.P.; Caracappa, A.; Fan, Q.

    1995-01-01

    Energy weighted integrals of the difference in helicity-dependent photo-production cross sections (σ 1/2 - σ 3/2 ) provide information on the nucleon's Spin-dependent Polarizability (γ), and on the spin-dependent part of the asymptotic forward Compton amplitude through the Drell-Hearn-Gerasimov (DHG) sum rule. (The latter forms the Q 2 =0 limit of recent spin-asymmetry experiments in deep-inelastic lepton-scattering.) There are no direct measurements of σ 1/2 or σ 3/2 , for either the proton or the neutron. Estimates from current π-photo-production multipole analyses, particularly for the proton-neutron difference, are in good agreement with relativistic-l-loop Chiral calculations (χPT) for γ but predict large deviations from the DHG sum rule. Either (a) both the 2-loop corrections to the Spin-Polarizability are large and the existing multipoles are wrong, or (b) modifications to the Drell-Hearn-Gerasimov sum rule are required to fully describe the isospin structure of the nucleon. The helicity-dependent photo-reaction amplitudes, for both the proton and the neutron, will be measured at LEGS from pion-threshold to 470 MeV. In these double-polarization experiments, circularly polarized photons from LEGS will be used with SPHICE, a new frozen-spin target consisting of rvec H · rvec D in the solid phase. Reaction channels will be identified in SASY, a large detector array covering about 80% of 4π. A high degree of symmetry in both target and detector will be used to minimize systematic uncertainties

  6. The build up of the correlation between halo spin and the large-scale structure

    Science.gov (United States)

    Wang, Peng; Kang, Xi

    2018-01-01

    Both simulations and observations have confirmed that the spin of haloes/galaxies is correlated with the large-scale structure (LSS) with a mass dependence such that the spin of low-mass haloes/galaxies tend to be parallel with the LSS, while that of massive haloes/galaxies tend to be perpendicular with the LSS. It is still unclear how this mass dependence is built up over time. We use N-body simulations to trace the evolution of the halo spin-LSS correlation and find that at early times the spin of all halo progenitors is parallel with the LSS. As time goes on, mass collapsing around massive halo is more isotropic, especially the recent mass accretion along the slowest collapsing direction is significant and it brings the halo spin to be perpendicular with the LSS. Adopting the fractional anisotropy (FA) parameter to describe the degree of anisotropy of the large-scale environment, we find that the spin-LSS correlation is a strong function of the environment such that a higher FA (more anisotropic environment) leads to an aligned signal, and a lower anisotropy leads to a misaligned signal. In general, our results show that the spin-LSS correlation is a combined consequence of mass flow and halo growth within the cosmic web. Our predicted environmental dependence between spin and large-scale structure can be further tested using galaxy surveys.

  7. A next-to-leading order QCD analysis of the spin structure function $g_1$

    CERN Document Server

    Adeva, B; Arik, E; Badelek, B; Bardin, G; Baum, G; Berglund, P; Betev, L; Birsa, R; De Botton, N R; Bradamante, Franco; Bravar, A; Bressan, A; Bültmann, S; Burtin, E; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Derro, B R; Deshpande, A A; Dhawan, S K; Dulya, C M; Eichblatt, S; Fasching, D; Feinstein, F; Fernández, C; Forthmann, S; Frois, Bernard; Gallas, A; Garzón, J A; Gilly, H; Giorgi, M A; von Goeler, E; Görtz, S; Gracia, G; De Groot, N; Grosse-Perdekamp, M; Haft, K; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; Kabuss, E M; Kageya, T; Karev, A G; Kessler, H J; Ketel, T; Kiryluk, J; Kiselev, Yu F; Krämer, Dietrich; Krivokhizhin, V G; Kröger, W; Kukhtin, V V; Kurek, K; Kyynäräinen, J; Lamanna, M; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Litmaath, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Meyer, W T; Van Middelkoop, G; Miller, D; Miyachi, Y; Mori, K; Moromisato, J H; Nassalski, J P; Naumann, Lutz; Niinikoski, T O; Oberski, J; Ogawa, A; Ozben, C; Pereira, H; Perrot-Kunne, F; Peshekhonov, V D; Piegia, R; Pinsky, L; Platchkov, S K; Pló, M; Pose, D; Postma, H; Pretz, J; Puntaferro, R; Rädel, G; Rijllart, A; Reicherz, G; Roberts, J; Rodríguez, M; Rondio, Ewa; Sabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Schiller, A; Sichtermann, E P; Simeoni, F; Smirnov, G I; Staude, A; Steinmetz, A; Stiegler, U; Stuhrmann, H B; Szleper, M; Tessarotto, F; Thers, D; Tlaczala, W; Tripet, A; Ünel, G; Velasco, M; Vogt, J; Voss, Rüdiger; Whitten, C; Windmolders, R; Willumeit, R; Wislicki, W; Witzmann, A; Ylöstalo, J; Zanetti, A M; Zaremba, K; Zhao, J

    1998-01-01

    We present a next-to-leading order QCD analysis of the presently available data on the spin structure function $g_1$ including the final data from the Spin Muon Collaboration (SMC). We present resu lts for the first moments of the proton, deuteron and neutron structure functions, and determine singlet and non-singlet parton distributions in two factorization schemes. We also test the Bjor ken sum rule and find agreement with the theoretical prediction at the level of 10\\%.

  8. RosettaEPR: rotamer library for spin label structure and dynamics.

    Directory of Open Access Journals (Sweden)

    Nathan S Alexander

    Full Text Available An increasingly used parameter in structural biology is the measurement of distances between spin labels bound to a protein. One limitation to these measurements is the unknown position of the spin label relative to the protein backbone. To overcome this drawback, we introduce a rotamer library of the methanethiosulfonate spin label (MTSSL into the protein modeling program Rosetta. Spin label rotamers were derived from conformations observed in crystal structures of spin labeled T4 lysozyme and previously published molecular dynamics simulations. Rosetta's ability to accurately recover spin label conformations and EPR measured distance distributions was evaluated against 19 experimentally determined MTSSL labeled structures of T4 lysozyme and the membrane protein LeuT and 73 distance distributions from T4 lysozyme and the membrane protein MsbA. For a site in the core of T4 lysozyme, the correct spin label conformation (Χ1 and Χ2 is recovered in 99.8% of trials. In surface positions 53% of the trajectories agree with crystallized conformations in Χ1 and Χ2. This level of recovery is on par with Rosetta performance for the 20 natural amino acids. In addition, Rosetta predicts the distance between two spin labels with a mean error of 4.4 Å. The width of the experimental distance distribution, which reflects the flexibility of the two spin labels, is predicted with a mean error of 1.3 Å. RosettaEPR makes full-atom spin label modeling available to a wide scientific community in conjunction with the powerful suite of modeling methods within Rosetta.

  9. Gross shell structure at high spin in heavy nuclei

    International Nuclear Information System (INIS)

    Deleplanque, Marie-Agnes; Frauendorf, Stefan; Pashkevich, Vitaly V.; Chu, S.Y.; Unzhakova, Anja

    2003-01-01

    Experimental nuclear moments of inertia at high spins along the yrast line have been determined systematically and found to differ from the rigid-body values. The difference is attributed to shell effect and these have been calculated microscopically. The data and quantal calculations are interpreted by means of the semiclassical Periodic Orbit Theory. From this new perspective, features in the moments of inertia as a function of neutron number and spin, as well as their relation to the shell energies can be understood. Gross shell effects persist up to the highest angular momenta observed

  10. Surface Acoustic Analog of Bloch Oscillations, Wannier-Stark Ladders and Landau-Zener Tunneling

    Science.gov (United States)

    de Lima, M. M.; Kosevich, Yu. A.; Santos, P. V.; Cantarero, A.

    2011-12-01

    In this contribution, we discuss the recent experimental demonstration of Wannier-Stark ladders, Bloch Oscillations and Landau Zener tunneling in a solid by means of surface acoustic waves propagating through perturbed grating structures.

  11. Strength Analysis on Ship Ladder Using Finite Element Method

    Science.gov (United States)

    Budianto; Wahyudi, M. T.; Dinata, U.; Ruddianto; Eko P., M. M.

    2018-01-01

    In designing the ship’s structure, it should refer to the rules in accordance with applicable classification standards. In this case, designing Ladder (Staircase) on a Ferry Ship which is set up, it must be reviewed based on the loads during ship operations, either during sailing or at port operations. The classification rules in ship design refer to the calculation of the structure components described in Classification calculation method and can be analysed using the Finite Element Method. Classification Regulations used in the design of Ferry Ships used BKI (Bureau of Classification Indonesia). So the rules for the provision of material composition in the mechanical properties of the material should refer to the classification of the used vessel. The analysis in this structure used program structure packages based on Finite Element Method. By using structural analysis on Ladder (Ladder), it obtained strength and simulation structure that can withstand load 140 kg both in static condition, dynamic, and impact. Therefore, the result of the analysis included values of safety factors in the ship is to keep the structure safe but the strength of the structure is not excessive.

  12. The effect of temperature and the spin excess parameter on neutron stars structure

    International Nuclear Information System (INIS)

    Abd-Alla, M.; Hassan, M.Y.M.; Ragab, H.S.

    1990-10-01

    A previous equation of state, deduced for thermal neutron matter with spin excess neutrons, is used to explore the effect of temperature and spin excess parameter on neutron star structure. The spin excess parameter is found to have a significant decreasing effect on the maximum mass of neutron stars, while it has an increasing effect on the central density of stable neutron stars. The behaviour of neutron star radius, for stars with central density less than three times normal nuclear matter density, depends on the spin excess parameter in a significant way. For stars having larger central density the spin excess parameter has a little decreasing effect on the star radius. The temperature is found to have a little increasing effect on both the star mass and its radius. The equation of state used is very stiff, but the resulting maximum masses lie within the range of neutron stars masses deduced from X-ray binaries. (author). 19 refs, 6 figs

  13. Structural and magnetic anomalies among the spin-chain ...

    Indian Academy of Sciences (India)

    Unknown

    sensitively depends on such crystallographic distortions. All the compositions exhibit spin-glass anomalies with an unusually large frequency dependence of the peak temperature in ac susceptibility in a temperature range below 50 K, interestingly obeying Vogel–Fulcher relationship even for the stoichiometric compounds.

  14. Spin Structure Change in Co-Substituted BiFeO3

    Science.gov (United States)

    Yamamoto, Hajime; Kihara, Takumi; Oka, Kengo; Tokunaga, Masashi; Mibu, Ko; Azuma, Masaki

    2016-06-01

    The spin structure in BiFe1-xCoxO3 (x = 0.05,0.10,0.15,0.20) was investigated as a function of Co substitution, temperature, and magnetic field. It was found that the cycloidal spin structure of BiFeO3 changed to a collinear one with spin canting and composition-independent spontaneous magnetization of ˜0.25 μB/f.u. for the Co substituted samples on heating. The collinear phase was stabilized under magnetic fields. The spin structure change was clarified also by the temperature dependence of 57Fe Mössbauer spectra, and the results indicated the first order nature of this transition.

  15. Atomic structure governed diversity of exchange-driven spin helices in Fe nanoislands: Experiment and theory

    Science.gov (United States)

    Fischer, Jeison A.; Sandratskii, Leonid M.; Phark, Soo-hyon; Sander, Dirk; Parkin, Stuart

    2017-10-01

    We combine spin-polarized scanning tunneling microscopy (SP-STM) and first-principles calculations to demonstrate the control of the wavelength of helical spin textures in Fe nanoislands by varying their atomic structure. We make use of the complexity of submonolayer growth of Fe on Cu(111) to prepare nanoislands characterized by different thickness and in-plane atomic structure. SP-STM results reveal that the magnetic states of different nanoislands are spin helices. The wavelength of the spin helices varies strongly. Calculations performed for Fe films with different thickness and in-plane atomic structure explain the strong variation of the wavelength by a subtle balance in the competition between ferromagnetic and antiferromagnetic exchange interactions. We identify the crucial role of the effectively enhanced weak antiferromagnetic exchange interactions between distant atoms.

  16. Templated growth of PFO-DBT nanorod bundles by spin coating: effect of spin coating rate on the morphological, structural, and optical properties

    OpenAIRE

    Fakir, Muhamad Saipul; Supangat, Azzuliani; Sulaiman, Khaulah

    2014-01-01

    In this study, the spin coating of template-assisted method is used to synthesize poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) nanorod bundles. The morphological, structural, and optical properties of PFO-DBT nanorod bundles are enhanced by varying the spin coating rate (100, 500, and 1,000 rpm) of the common spin coater. The denser morphological distributions of PFO-DBT nanorod bundles are favorably yielded at the low spin coating rate of 100 rp...

  17. Understanding the Behaviour of Infinite Ladder Circuits

    Science.gov (United States)

    Ucak, C.; Yegin, K.

    2008-01-01

    Infinite ladder circuits are often encountered in undergraduate electrical engineering and physics curricula when dealing with series and parallel combination of impedances, as a part of filter design or wave propagation on transmission lines. The input impedance of such infinite ladder circuits is derived by assuming that the input impedance does…

  18. Laddering em pesquisa de marketing

    Directory of Open Access Journals (Sweden)

    Tânia Modesto Veludo-de-Oliveira

    Full Text Available O artigo discute a técnica de pesquisa laddering em marketing, considerando a proposta de renovação de conhecimentos sobre metodologia na área. Para isso investiga diversos estudos, artigos e pesquisas que tratam do assunto em nível nacional e internacional. O conceito de cadeias meios-fins é abordado pela estrutura teórica que fundamenta a técnica, ligando atributos, conseqüências percebidas do consumo e valores pessoais relativos a um produto. O artigo segue com a explicação dos procedimentos de campo, como a entrevista e a análise dos dados. A laddering é um instrumento de pesquisa qualitativa bastante útil e poderoso, mas ainda pouco utilizado tanto por acadêmicos como por profissionais de mercado, no Brasil, provavelmente por desconhecimento e pouca divulgação. Cabe, portanto, uma maior disseminação de seu uso.

  19. Quantum interference measurement of spin interactions in a bio-organic/semiconductor device structure

    Science.gov (United States)

    Deo, Vincent; Zhang, Yao; Soghomonian, Victoria; Heremans, Jean J.

    2015-03-01

    Quantum interference is used to measure the spin interactions between an InAs surface electron system and the iron center in the biomolecule hemin in nanometer proximity in a bio-organic/semiconductor device structure. The interference quantifies the influence of hemin on the spin decoherence properties of the surface electrons. The decoherence times of the electrons serve to characterize the biomolecule, in an electronic complement to the use of spin decoherence times in magnetic resonance. Hemin, prototypical for the heme group in hemoglobin, is used to demonstrate the method, as a representative biomolecule where the spin state of a metal ion affects biological functions. The electronic determination of spin decoherence properties relies on the quantum correction of antilocalization, a result of quantum interference in the electron system. Spin-flip scattering is found to increase with temperature due to hemin, signifying a spin exchange between the iron center and the electrons, thus implying interactions between a biomolecule and a solid-state system in the hemin/InAs hybrid structure. The results also indicate the feasibility of artificial bioinspired materials using tunable carrier systems to mediate interactions between biological entities.

  20. M-theory on eight-manifolds revisited: N = 1 supersymmetry and generalized Spin(7) structures

    International Nuclear Information System (INIS)

    Tsimpis, Dimitrios

    2006-01-01

    The requirement of N = 1 supersymmetry for M-theory backgrounds of the form of a warped product M x w X, where X is an eight-manifold and M is three-dimensional Minkowski or AdS space, implies the existence of a nowhere-vanishing Majorana spinor ξ on X. ξ lifts to a nowhere-vanishing spinor on the auxiliary nine-manifold Y: = X x S 1 , where S 1 is a circle of constant radius, implying the reduction of the structure group of Y to Spin(7). In general, however, there is no reduction of the structure group of X itself. This situation can be described in the language of generalized Spin(7) structures, defined in terms of certain spinors of Spin(TY+T*Y). We express the condition for N = 1 supersymmetry in terms of differential equations for these spinors. In an equivalent formulation, working locally in the vicinity of any point in X in terms of a 'preferred' Spin(7) structure, we show that the requirement of N = 1 supersymmetry amounts to solving for the intrinsic torsion and all irreducible flux components, except for the one lying in the 27 of Spin(7), in terms of the warp factor and a one-form L on X (not necessarily nowhere-vanishing) constructed as a ξ bilinear; in addition, L is constrained to satisfy a pair of differential equations. The formalism based on the group Spin(7) is the most suitable language in which to describe supersymmetric compactifications on eight-manifolds of Spin(7) structure, and/or small-flux perturbations around supersymmetric compactifications on manifolds of Spin(7) holonomy

  1. Investigations on the local structure and the spin-Hamiltonian ...

    Indian Academy of Sciences (India)

    MS received 23 October 2014; revised 23 November 2015; accepted 16 December 2015; published online 13 July 2016. Abstract. The spin-Hamiltonian parameters (g factors g , g⊥ and hyperfine ..... Here, t2 ≈ 3 and t4 ≈ 5 are the power-law expo- nents [10–13]. ¯A2(R) and ¯A4(R) are the intrinsic parameters, with the ...

  2. Ferromagnetic domain structures and spin configurations measured in doped manganite

    DEFF Research Database (Denmark)

    He, J.Q.; Volkov, V.V.; Beleggia, Marco

    2010-01-01

    We report on measurements of the spin configuration across ferromagnetic domains in La0.325Pr0.3Ca0.375MnO3 films obtained by means of low-temperature Lorentz electron microscopy with in situ magnetizing capabilities. Due to the particular crystal symmetry of the material, we observe two sets of ...... and the crystal symmetry might affect the magnetoresistivity under an applied magnetic field in a strongly correlated electron system....

  3. STUDY OF THE HIGH-SPIN STRUCTURE OF PM-146

    NARCIS (Netherlands)

    RZACAURBAN, T; DURELL, JL; PHILLIPS, WR; VARLEY, BJ; HESS, CP; PEARSON, CJ; VERMEER, WJ; VIEU, C; DIONISIO, JS; PAUTRAT, M; Urban, W

    1995-01-01

    Excited states in Pm-146 have been investigated through the Xe-136(N-15,5n) and the Nd-146(d,xn) compound-nucleus reactions. A level scheme extending up to 6.9 MeV of excitation energy and (I = 25HBAR) is proposed. Most of the high-spin levels are interpreted in terms of multi-particle-hole states

  4. Arbitrary amplitude magnetosonic solitary and shock structures in spin quantum plasma

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, Biswajit [Department of Mathematics, West Bengal State University, Barasat, Kolkata-700126 (India); Sinha, Anjana; Roychoudhury, Rajkumar; Khan, Manoranjan [Department of Instrumentation Science, Jadavpur University, Kolkata-700 032 (India)

    2013-11-15

    A nonlinear analysis is carried out for the arbitrary amplitude magnetosonic solitary and shock structures in spin quantum plasmas. A quantum magnetohydrodynamic model is used to describe the magnetosonic quantum plasma with the Bohm potential and the pressure like spin force for electrons. Analytical calculations are used to simplify the basic equations, which are then studied numerically. It is shown that the magnetic diffusivity is responsible for dissipation, which causes the shock-like structures rather than the soliton structures. Additionally, wave speed, Zeeman energy, and Bohm potential are found to have significant impact on the shock wave structures.

  5. Spin structure function measurements with polarized protons and electrons at HERA

    International Nuclear Information System (INIS)

    Ball, R.D.; Deshpande, A.; Forte, S.; Hughes, V.W.; Lichtenstadt, J.; Ridolfi, G.

    1995-01-01

    Useful insights into the spin structure functions of the nucleon can be achieved by measurements of spin-dependent asymmetries in inclusive scattering of high energy polarized electrons by high energy polarized protons at HERA. Such an experiment would be a natural extension of the polarized lepton-nucleon scattering experiments presently carried out at CERN and SLAC. We present here estimates of possible data in the extended kinematic range of HERA and associated statistical errors. (orig.)

  6. The MONSTER solves nuclear structure problems at low and high spins

    International Nuclear Information System (INIS)

    Hammaren, E.; Schmid, K.W.; Gruemmer, F.

    1984-01-01

    A microscopic, particle-number and spin conserving nuclear structure model is discussed. Within a unique theory the model can describe excitation energies, moments, transitions and spectroscopic factors at low and high spins of odd-mass and doubly-even nuclei in all mass regions. With a realistic two-body Hamiltonian extracted via a G-matric description from nucleon-nucleon scattering data. The model is here applied to nuclei in the A=130 region

  7. Hysteresis and compensation behaviors of mixed spin-2 and spin-1 hexagonal Ising nanowire core–shell structure

    International Nuclear Information System (INIS)

    Masrour, R.; Jabar, A.; Benyoussef, A.; Hamedoun, M.; Bahmad, L.

    2015-01-01

    The magnetic behaviors of a mixed spins (2-1) hexagonal Ising nanowire with core–shell structure are investigated by using the Monte Carlo simulations. The thermal magnetizations, the magnetic susceptibilities and the transition temperatures of core–shell are studied for different values of crystal field and exchange interactions. The thermal and magnetic hysteresis cycles are given for different values of the crystal field. - Highlights: • Critical temperature increase when exchange interaction increasing in core-shell. • Hysteresis loop areas decrease at above transition temperature. • Magnetic coercive field decrease when crystal field increasing. • Magnetic coercive field increase when exchange interaction increasing

  8. Spin-dependent transport properties of a GaMnAs-based vertical spin metal-oxide-semiconductor field-effect transistor structure

    International Nuclear Information System (INIS)

    Kanaki, Toshiki; Asahara, Hirokatsu; Ohya, Shinobu; Tanaka, Masaaki

    2015-01-01

    We fabricate a vertical spin metal-oxide-semiconductor field-effect transistor (spin-MOSFET) structure, which is composed of an epitaxial single-crystal heterostructure with a ferromagnetic-semiconductor GaMnAs source/drain, and investigate its spin-dependent transport properties. We modulate the drain-source current I DS by ∼±0.5% with a gate-source voltage of ±10.8 V and also modulate I DS by up to 60% with changing the magnetization configuration of the GaMnAs source/drain at 3.5 K. The magnetoresistance ratio is more than two orders of magnitude higher than that obtained in the previous studies on spin MOSFETs. Our result shows that a vertical structure is one of the hopeful candidates for spin MOSFET when the device size is reduced to a sub-micron or nanometer scale

  9. Cutting and dismantling of the South West ladder of the Atucha I nuclear power plant

    International Nuclear Information System (INIS)

    Anasco, Roberto

    2006-01-01

    The metallic ladder built in stainless steel was used originally to check the welding of the reactor pressure vessel. It was located between the thermal insulation and reactor pressure vessel. Because of a failure in the mechanism, which let the ladder runs around the vessel, it had to be removed. A special tool remotely operated was designed to make different cuts in the bottom of the structure in a very high radioactive location [es

  10. An overview of recent nucleon spin structure measurements at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Allada, Kalyan [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-02-01

    Jefferson Lab have made significant contributions to improve our knowledge of the longitudinal spin structure by measuring polarized structure functions, g1 and g2, down to Q2 = 0.02 GeV2. The low Q2 data is especially useful in testing the Chiral Perturbation theory (cPT) calculations. The spin-dependent sum rules and the spin polarizabilities, constructed from the moments of g1 and g2, provide an important tool to study the longitudinal spin structure. We will present an overview of the experimental program to measure these structure functions at Jefferson Lab, and present some recent results on the neutron polarizabilities, proton g1 at low Q2, and proton and neutron d2 measurement. In addition to this, we will discuss the transverse spin structure of the nucleon which can be accessed using chiral-odd transversity distribution (h1), and show some results from measurements done on polarized 3He target in Hall A.

  11. The Spin Structure of the Proton at Low Q2: A Measurement of the Structure Function g2p

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Chao [Univ. of Virginia, Charlottesville, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-08-31

    The spin structure of the nucleon has remained as one of the key points of interest in hadronic physics, which has attracted many efforts from both experimentalists and theorists. Quantum Chromodynamics (QCD) is the fundamental theory that describes the strong interaction. It has been verified in the asymptotically free region. However, the non-perturbative confinement of quarks within the nucleon is still not well understood within QCD. In the non-perturbative regime, low-energy effective field theories such as chiral perturbation theory (XPT) provide predictions for the spin structure functions. The neutron spin structure functions, gp1 and gp2 , and the proton spin structure function, gp1, have been measured over a wide kinematic range and compared with the theoretical predictions. However, the proton spin structure function, gp2, remains largely unmeasured. The E08-027 collaboration successfully performed the first measurement of the inclusive electron-proton scattering in the kinematic range 0.02 < Q2 < 0.2 GeV2. The experiment took place in experimental Hall A at Jefferson Lab in 2012. A longitudinally polarized electron beam with incident energies between 1.1 GeV and 3.3 GeV was scattered from a longitudinally or transversely polarized NH3 target. Asymmetries and polarized cross-section differences were measured in the resonance region to extract the proton spin structure functions g2. The results allow us to obtain the generalized spin polarizabilities γ0 and δLT and test the Burkhardtt-Cottingham (BC) sum rule. Chiral perturbation theory is expected to work in this kinematic range and this measurement of δLT will give a benchmark test to XPT calculations. This thesis will discuss preliminary results from the E08-027 data analysis.

  12. Growth and Electronic Structure of Heusler Compounds for Use in Electron Spin Based Devices

    Science.gov (United States)

    Patel, Sahil Jaykumar

    Spintronic devices, where information is carried by the quantum spin state of the electron instead of purely its charge, have gained considerable interest for their use in future computing technologies. For optimal performance, a pure spin current, where all electrons have aligned spins, must be generated and transmitted across many interfaces and through many types of materials. While conventional spin sources have historically been elemental ferromagnets, like Fe or Co, these materials pro duce only partially spin polarized currents. To increase the spin polarization of the current, materials like half-metallic ferromagnets, where there is a gap in the minority spin density of states around the Fermi level, or topological insulators, where the current transport is dominated by spin-locked surface states, show promise. A class of materials called Heusler compounds, with electronic structures that range from normal metals, to half metallic ferromagnets, semiconductors, superconductors and even topological insulators, interfaces well with existing device technologies, and through the use of molecular beam epitaxy (MBE) high quality heterostructures and films can be grown. This dissertation examines the electronic structure of surfaces and interfaces of both topological insulator (PtLuSb-- and PtLuBi--) and half-metallic ferromagnet (Co2MnSi-- and Co2FeSi--) III-V semiconductor heterostructures. PtLuSb and PtLuBi growth by MBE was demonstrated on Alx In1--xSb (001) ternaries. PtLuSb (001) surfaces were observed to reconstruct with either (1x3) or c(2x2) unit cells depending on Sb overpressure and substrate temperature. viii The electronic structure of these films was studied by scanning tunneling microscopy/spectroscopy (STM/STS) and photoemission spectroscopy. STS measurements as well as angle resolved photoemission spectropscopy (ARPES) suggest that PtLuSb has a zero-gap or semimetallic band structure. Additionally, the observation of linearly dispersing surface

  13. Shell structure at high spin and the influence on nuclear shapes

    International Nuclear Information System (INIS)

    Khoo, T.L.; Chowdhury, P.; Ahmad, I.

    1982-01-01

    Nuclear structure at high spin is influenced by a combination of liquid-drop and shell-structure effects. For N 90. The competition between oblate and prolate driving effects leads to a prolate-to-oblate shape transition in 154 Dy 88 . The role of rotation-aligned configurations in the shape change is discussed

  14. A study of manufacturing tubes with nano/ultrafine grain structure by stagger spinning

    International Nuclear Information System (INIS)

    Xia, Qinxiang; Xiao, Gangfeng; Long, Hui; Cheng, Xiuquan; Yang, Baojian

    2014-01-01

    Highlights: • Proposing a method of manufacturing tubes with nano/ultrafine crystal. • Obtaining the refined ferritic grains with an size of 500 nm after stagger spinning. • Obtaining the equiaxial ferritic grains with an size of 600 nm after annealing. - Abstract: A new method of manufacturing tubes with nano/ultrafine grain structure by stagger spinning and recrystallization annealing is proposed in this study. Two methods of the stagger spinning process are developed, the corresponding macroforming quality, microstructural evolution and mechanical properties of the spun tubes made of ASTM 1020 steel are analysed. The results reveal that a good surface smoothness and an improved spin-formability of spun parts can be obtained by the process combining of 3-pass spinning followed by a 580 °C × 0.5 h static recrystallization and 2-pass spinning with a 580 °C × 1 h static recrystallization annealing under the severe thinning ratio of wall thickness reduction. The ferritic grains with an average initial size of 50 μm are refined to 500 nm after stagger spinning under the 87% thinning ratio of wall thickness reduction. The equiaxial ferritic grains with an average size of 600 nm are generated through re-nucleation and grain growth by subsequent recrystallization annealing at 580 °C for 1 h heat preservation. The tensile strength of spun tubes has been founded to be proportional to the reciprocal of layer spacing of pearlite (LSP), and the elongation is inversely proportional to the reciprocal of LSP. This study shows that the developed method of stagger power spinning has the potential to be used to manufacture bulk metal components with nano/ultrafine grain structure

  15. Templated growth of PFO-DBT nanorod bundles by spin coating: effect of spin coating rate on the morphological, structural, and optical properties.

    Science.gov (United States)

    Fakir, Muhamad Saipul; Supangat, Azzuliani; Sulaiman, Khaulah

    2014-01-01

    In this study, the spin coating of template-assisted method is used to synthesize poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) nanorod bundles. The morphological, structural, and optical properties of PFO-DBT nanorod bundles are enhanced by varying the spin coating rate (100, 500, and 1,000 rpm) of the common spin coater. The denser morphological distributions of PFO-DBT nanorod bundles are favorably yielded at the low spin coating rate of 100 rpm, while at high spin coating rate, it is shown otherwise. The auspicious morphologies of highly dense PFO-DBT nanorod bundles are supported by the augmented absorption and photoluminescence.

  16. Dispersion characteristics of spin-electromagnetic waves in planar multiferroic structures

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, Andrey A.; Ustinov, Alexey B. [Department of Physical Electronics and Technology, St. Petersburg Electrotechnical University, St. Petersburg 197376 (Russian Federation); Department of Mathematics and Physics, Lappeenranta University of Technology, Lappeenranta 53850 (Finland); Vitko, Vitaliy V.; Semenov, Alexander A.; Mironenko, Igor G. [Department of Physical Electronics and Technology, St. Petersburg Electrotechnical University, St. Petersburg 197376 (Russian Federation); Belyavskiy, Pavel Yu.; Kalinikos, Boris A. [Department of Physical Electronics and Technology, St. Petersburg Electrotechnical University, St. Petersburg 197376 (Russian Federation); International Laboratory “MultiferrLab,” ITMO University, St. Petersburg 197101 (Russian Federation); Stashkevich, Andrey A. [International Laboratory “MultiferrLab,” ITMO University, St. Petersburg 197101 (Russian Federation); LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 93430 Villetaneuse (France); Lähderanta, E. [Department of Mathematics and Physics, Lappeenranta University of Technology, Lappeenranta 53850 (Finland)

    2015-11-14

    A method of approximate boundary conditions is used to derive dispersion relations for spin-electromagnetic waves (SEWs) propagating in thin ferrite films and in multiferroic layered structures. A high accuracy of this method is proven. It was shown that the spin-electromagnetic wave propagating in the structure composed of a thin ferrite film, a thin ferroelectric film, and a slot transmission line is formed as a result of hybridization of the surface spin wave in the ferrite film and the electromagnetic wave in the slot-line. The structure demonstrates dual electric and magnetic field tunability of the SEW spectrum. The electric field tunability is provided by the thin ferroelectric film. Its efficiency increases with an increase in the thicknesses of the ferrite and ferroelectric films and with a decrease in the slot-line gap width. The theory is confirmed by experimental data.

  17. High-spin states and level structure in 84Rb

    International Nuclear Information System (INIS)

    Shen Shuifa; Han Guangbing; Wen Shuxian; Gu Jianzhong; Wu Xiaoguang; Zhu Lihua; He Chuangye; Li Guangsheng; Yu Beibei; Pan Feng; Zhu Jianyu; Draayer, J. P.; Wen Tingdun; Yan, Yupeng

    2010-01-01

    High-spin states in 84 Rb have been studied by using the 70 Zn( 18 O,p3n) 84 Rb reaction at beam energy of 75 MeV. The γ-γ coincidence, excitation function, and ratios for directional correlation of oriented states were determined. A new level scheme was established in which the positive- and negative-parity bands have been extended up to 17 + and 17 - with an excitation energy of about 7 MeV. The signature splitting and signature inversion of the positive-parity yrast band were observed. To understand the microscopic origin of the signature inversion in the yrast positive-parity bands of doubly odd Rb nuclei, as an example, we performed calculations using the projected shell model to describe the energy spectra in 84 Rb. It can be seen that the main features are reproduced in the calculations. This analysis shows that the signature splitting, especially its inversion, can be reproduced by varying only the γ deformation with increasing spin. To research the deformation of 84 Rb carefully, we calculate the total Routhian surfaces of positive-parity yrast states by the cranking shell model formalism. In addition, the results of theoretical calculations about the negative-parity yrast band in 84 Rb with configuration π(p 3/2 ,f 5/2 ) x νg 9/2 are compared with experimental data, and a band diagram calculated for this band is also shown to extract physics from the numerical results.

  18. Available friction of ladder shoes and slip potential for climbing on a straight ladder.

    Science.gov (United States)

    Chang, Wen-Ruey; Chang, Chien-Chi; Matz, Simon

    2005-07-15

    Straight ladder accidents are a major safety problem. As a leading cause of injuries involving straight ladders, slips at the ladder base occur when the required friction exceeds the available friction at the ladder shoe and floor interface. The objectives of this experiment were to measure the available friction at the base of a portable straight ladder in contact with a floor and to estimate the slip potential of the ladder. The results of friction measurements indicated that the measured friction coefficient on the oily surfaces differed among the six commercially available ladder shoes evaluated. A statistical model was used to compare the available friction results from the current study with the friction requirements under different climbing conditions from a previous study based on their stochastic distributions to estimate the slip potential at the base of the ladder. The results showed that different climbing conditions used in the previous study could be supported by available friction on dry surfaces. However, when the ladder was put onto oily surfaces, resulting in a significant reduction in the available friction due to contamination, slip potential was significantly increased.

  19. The magnetic structure on the ground state of the equilateral triangular spin tube

    International Nuclear Information System (INIS)

    Matsui, Kazuki; Goto, Takayuki; Manaka, Hirotaka; Miura, Yoko

    2016-01-01

    The ground state of the frustrated equilateral triangular spin tube CsCrF 4 is still hidden behind a veil though NMR spectrum broaden into 2 T at low temperature. In order to investigate the spin structure in an ordered state by 19 F-NMR, we have determined the anisotropic hyperfine coupling tensors for each three fluorine sites in the paramagnetic state. The measurement field was raised up to 10 T to achieve highest resolution. The preliminary analysis using the obtained hyperfine tensors has shown that the archetypal 120°-type structure in ab-plane does not accord with the NMR spectra of ordered state.

  20. The magnetic structure on the ground state of the equilateral triangular spin tube

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Kazuki, E-mail: k703861@eagle.sophia.ac.jp; Goto, Takayuki [Sophia University, Physics Division (Japan); Manaka, Hirotaka [Kagoshima University, Graduate School of Science and Engineering (Japan); Miura, Yoko [Suzuka National College of Technology (Japan)

    2016-12-15

    The ground state of the frustrated equilateral triangular spin tube CsCrF{sub 4} is still hidden behind a veil though NMR spectrum broaden into 2 T at low temperature. In order to investigate the spin structure in an ordered state by {sup 19}F-NMR, we have determined the anisotropic hyperfine coupling tensors for each three fluorine sites in the paramagnetic state. The measurement field was raised up to 10 T to achieve highest resolution. The preliminary analysis using the obtained hyperfine tensors has shown that the archetypal 120°-type structure in ab-plane does not accord with the NMR spectra of ordered state.

  1. Structural study of the re-entrant spin-glass behaviour of Fe-Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Martin Rodriguez, D. [Bragg Institute, Australian Nuclear Science and Technology Organisation, PMB 1, Menai NSW 2234 (Australia)]. E-mail: dmr@ansto.gov.au; Plazaola, F. [Elektrika eta Elektronika Saila, UPV-EHU, 644 P.K., 48080 Bilbao (Spain); Garitaonandia, J.S. [Fisika Aplikatua II Saila, UPV-EHU, 644 P.K., 48080 Bilbao (Spain); Cuello, G.J. [Institute Laue Langevin, 6 rue Jules Horowitz, B.P. 156, 38042 Grenoble (France)

    2007-09-15

    Neutron powder diffraction measurements were performed on Fe{sub 70}Al{sub 30} alloy in order to determine the relationship between the magnetic behaviour and the structural changes observed in this alloy. Results show that the re-entrant spin-glass behaviour is linked with D03 structure. There is a strong correlation between the lattice parameter and the diffraction peak intensity and all the magnetic changes reported in literature can be explained in terms of this relationship. Finally, magnetovolume effects similar to invar effect are reported in the spin-glass phase.

  2. Structural study of the re-entrant spin-glass behaviour of Fe-Al alloys

    Science.gov (United States)

    Martín Rodríguez, D.; Plazaola, F.; Garitaonandia, J. S.; Cuello, G. J.

    2007-09-01

    Neutron powder diffraction measurements were performed on Fe 70Al 30 alloy in order to determine the relationship between the magnetic behaviour and the structural changes observed in this alloy. Results show that the re-entrant spin-glass behaviour is linked with D03 structure. There is a strong correlation between the lattice parameter and the diffraction peak intensity and all the magnetic changes reported in literature can be explained in terms of this relationship. Finally, magnetovolume effects similar to invar effect are reported in the spin-glass phase.

  3. Critical Thinking via the Abstraction Ladder.

    Science.gov (United States)

    Seabury, Marcia Bundy

    1991-01-01

    Discusses strategies (based on S. I. Hayakawa's abstraction ladder) to encourage connected thinking in student writing. Describes a recent cross-disciplinary workshop seeking to improve student essay writing and evaluation. (KEH)

  4. Mass ladder operators from spacetime conformal symmetry

    Science.gov (United States)

    Cardoso, Vitor; Houri, Tsuyoshi; Kimura, Masashi

    2017-07-01

    Ladder operators can be useful constructs, allowing for unique insight and intuition. In fact, they have played a special role in the development of quantum mechanics and field theory. Here, we introduce a novel type of ladder operators, which map a scalar field onto another massive scalar field. We construct such operators, in arbitrary dimensions, from closed conformal Killing vector fields, eigenvectors of the Ricci tensor. As an example, we explicitly construct these objects in anti-de Sitter (A d S ) spacetime and show that they exist for masses above the Breitenlohner-Freedman bound. Starting from a regular seed solution of the massive Klein-Gordon equation, mass ladder operators in AdS allow one to build a variety of regular solutions with varying boundary condition at spatial infinity. We also discuss mass ladder operator in the context of spherical harmonics, and the relation between supersymmetric quantum mechanics and so-called Aretakis constants in an extremal black hole.

  5. Interface-induced spin Hall magnetoresistance enhancement in Pt-based tri-layer structure.

    Science.gov (United States)

    Huang, Shun-Yu; Li, Hong-Lin; Chong, Cheong-Wei; Chang, Yu-Ying; Lee, Min-Kai; Huang, Jung-Chun-Andrew

    2018-01-08

    In this study, we integrated bilayer structure of covered Pt on nickel zinc ferrite (NZFO) and CoFe/Pt/NZFO tri-layer structure by pulsed laser deposition system for a spin Hall magnetoresistance (SMR) study. In the bilayer structure, the angular-dependent magnetoresistance (MR) results indicate that Pt/NZFO has a well-defined SMR behavior. Moreover, the spin Hall angle and the spin diffusion length, which were 0.0648 and 1.31 nm, respectively, can be fitted by changing the Pt thickness in the longitudinal SMR function. Particularly, the MR ratio of the bilayer structure (Pt/NZFO) has the highest changing ratio (about 0.135%), compared to the prototype structure Pt/Y 3 Fe 5 O 12 (YIG) because the NZFO has higher magnetization. Meanwhile, the tri-layer samples (CoFe/Pt/NZFO) indicate that the MR behavior is related with CoFe thickness as revealed in angular-dependent MR measurement. Additionally, comparison between the tri-layer structure with Pt/NZFO and CoFe/Pt bilayer systems suggests that the SMR ratio can be enhanced by more than 70%, indicating that additional spin current should be injected into Pt layer.

  6. Towards automatic verification of ladder logic programs

    OpenAIRE

    Zoubek , Bohumir; Roussel , Jean-Marc; Kwiatkowska , Martha

    2003-01-01

    International audience; Control system programs are usually validated by testing prior to their deployment. Unfortunately, testing is not exhaustive and therefore it is possible that a program which passed all the required tests still contains errors. In this paper we apply techniques of automatic verification to a control program written in ladder logic. A model is constructed mechanically from the ladder logic program and subjected to automatic verification against requirements that include...

  7. The transient ladder synchronization of chaotic systems

    International Nuclear Information System (INIS)

    Chen, H.-K.; Sheu, L.-J.

    2006-01-01

    A new type for chaotically synchronizing systems, transient ladder chaos synchronization, is proposed in this Letter. For some physical systems, chaotic synchronization is possible in only some of the variables. It is shown that, for the non-synchronizing variable, synchronization up to a constant difference for t 1 = 2 is possible. The transient ladder chaos synchronization and anti-synchronization are illustrated by using two identical chaotic Froude pendulums. Numerical simulations are shown for demonstration

  8. Low temperature polarized target for spin structure studies of nucleons at COMPASS

    CERN Document Server

    Pesek, Michael

    In presented thesis we describe concept of Deep Inelastic Scattering of leptons on nucleons in context of nucleon spin structure studies. Both polarized and unpolarized cases are discussed and concept of Transverse Momentum Dependent Parton Distribution Functions (TMD PDF) is introduced. The possibility of TMDs measurement using Semi-inclusive DIS (SIDIS) is described along with related results from COMPASS experiment. The future Drell-Yan programme at COMPASS is briefly mentioned and its importance is presented on the universality test i.e. change of sign of T-odd TMDs when measured in Drell-Yan and SIDIS. The importance of Polarized Target (PT) for spin structure studies is highlighted and principles of Dynamic Nuclear Polarization (DNP) are given using both Solid effect and spin temperature concept. COMPASS experiment is described in many details with accent given to PT. Finally the thermal equilibrium (TE) calibration procedure is described and carried out for 2010 and 2011 physics runs at COMPASS. The av...

  9. Spin-resolved magnetic studies of focused ion beam etched nano-sized magnetic structures

    International Nuclear Information System (INIS)

    Li Jian; Rau, Carl

    2005-01-01

    Scanning ion microscopy with polarization analysis (SIMPA) is used to study the spin-resolved surface magnetic structure of nano-sized magnetic systems. SIMPA is utilized for in situ topographic and spin-resolved magnetic domain imaging as well as for focused ion beam (FIB) etching of desired structures in magnetic or non-magnetic systems. Ultra-thin Co films are deposited on surfaces of Si(1 0 0) substrates, and ultra-thin, tri-layered, bct Fe(1 0 0)/Mn/bct Fe(1 0 0) wedged magnetic structures are deposited on fcc Pd(1 0 0) substrates. SIMPA experiments clearly show that ion-induced electrons emitted from magnetic surfaces exhibit non-zero electron spin polarization (ESP), whereas electrons emitted from non-magnetic surfaces such as Si and Pd exhibit zero ESP, which can be used to calibrate sputtering rates in situ. We report on new, spin-resolved magnetic microstructures, such as magnetic 'C' states and magnetic vortices, found at surfaces of FIB patterned magnetic elements. It is found that FIB milling has a negligible effect on surface magnetic domain and domain wall structures. It is demonstrated that SIMPA can evolve into an important and efficient tool to study magnetic domain, domain wall and other structures as well as to perform magnetic depth profiling of magnetic nano-systems to be used in ultra-high density magnetic recording and in magnetic sensors

  10. The Spin Structure of the Neutron Determined Using a Polarized He-3 Target

    Energy Technology Data Exchange (ETDEWEB)

    Middleton, H

    2004-01-06

    Described is a study of the internal spin structure of the neutron performed by measuring the asymmetry in spin-dependent deep inelastic scattering of polarized electrons from nuclear polarized {sup 3}He. Stanford Linear Accelerator experiment E142's sample of 400 million scattering events collected at beam energies between 19 and 26 GeV led to the most precise measurement of a nucleon spin structure function to date. The {sup 3}He target represents a major advance in polarized target technology, using the technique of spin exchange with optically pumped rubidium vapor to produce a typical {sup 3}He nuclear polarization of 34% in a 30cm long target cell with a gas density of 2.3 x 10{sup 20} cm{sup -3}. The target polarization was measured to {+-}7% using an Adiabatic Fast Passage NMR system calibrated with the thermal equilibrium polarization of the protons in a sample of water. The relatively high polarization and target thickness were the result of the development of large volume glass target cells which had inherent nuclear spin relaxation times for the {sup 3}He gas of as long as 70 hours. A target cell production procedure is presented which focuses on special glass blowing techniques to minimize surface interactions with the {sup 3}He nuclei and careful gas purification and vacuum system procedures to reduce relaxation inducing impurities.

  11. Internal Spin Structure of the Nucleon in Polarized Deep Inelastic Muon-Nucleon Scattering

    International Nuclear Information System (INIS)

    Wislicki, W.

    1998-01-01

    We present the study of the internal spin structure of the nucleon in spin-dependent deep inelastic scattering of muons on nucleons. The data were taken by the NA47 experiment of the Spin Muon Collaboration (SMC) on the high energy muon beam at CERN. The experiment used the polarized proton and deuteron targets. The structure function g 1 p (x) and g 1 d (x) were determined from the asymmetries of the spin-dependent event rates in the range of 0.003 2 >=10 GeV 2 . Using the first moments of these structure functions an agreement with the Bjorken sum rule prediction was found within one standard deviation. The first moments of g 1 (x), for both proton and deuteron, are smaller than the Ellis-Jaffe sum rule prediction. This disagreement can be interpreted in terms of negative polarization of the strange sea in the nucleon. The singlet part of the axial current matrix element can be interpreted as an overall spin carried by quarks in the nucleon. Its value is significantly smaller than nucleon spin. Semi-inclusive asymmetries of yields of positive and negative hadrons produced on both targets were also measured and analysed in term of quark-parton model, together with inclusive asymmetries. From this analysis the quark spin distributions were determined, separately for valence u and d quarks and for non-strange sea quarks. Valence u quarks are positively polarized and their polarization increases with x. Valence d quarks are negatively polarized and their polarization does not exhibit any x-dependence. The non-strange sea is unpolarized in the whole measured range of x. The first moments of the valance quark spin distributions were found consistent with the values obtained from weak decay constants F and D and their second moments are consistent with lattice QCD calculations. In the QCD analysis of the world data the first moment of the gluon spin distribution was found with a large error. Also, a search for a non-perturbative anomaly at high x was done on the world

  12. Spin structure of the 3He from the dd → 3Hen reaction

    International Nuclear Information System (INIS)

    Ladygin, V.P.; Ladygina, N.B.

    1995-01-01

    The polarization observables in the reaction dd → 3 Hen are considered. Their high sensitivity to the 3 He wave function at short distances is shown. Using of both polarized target and beam allows to extend sufficiently the number of possible experiments and to separate 3 He structure from the reaction mechanisms using different relative orientations of initial deuteron spins. 27 refs., 5 figs

  13. Structure of high spin states of 76Kr and 78Kr nuclei

    Indian Academy of Sciences (India)

    Following a fully self-consistent cranked Hartree-Fock-Bogoliubov (CHFB) approach with a pairing+quadrupole+hexadecapole model interaction Hamiltonian the structure of the yrast states of 76,78Kr nuclei is studied up to angular momentum = 24. Evolution of the shape with spin, and rotation alignment of proton as well ...

  14. Structure in cohesive powder studied with spin-echo small angle neutron scattering

    NARCIS (Netherlands)

    Andersson, R.; Bouwman, W.G.; Luding, Stefan; de Schepper, I.M.

    2008-01-01

    Extracting structure and ordering information from the bulk of granular materials is a challenging task. Here we present Spin-Echo Small Angle Neutron Scattering Measurements in combination with computer simulations on a fine powder of silica, before and after uniaxial compression. The cohesive

  15. Structure in cohesive powders studied with spin-echo small angle neutron scattering

    NARCIS (Netherlands)

    Andersson, R.; Bouwman, W.G.; Luding, S.; De Schepper, I.M.

    2008-01-01

    Extracting structure and ordering information from the bulk of granular materials is a challenging task. Here we present Spin-Echo Small Angle Neutron Scattering Measurements in combination with computer simulations on a fine powder of silica, before and after uniaxial compression. The cohesive

  16. Structure of high spin states of 76Kr and 78Kr nuclei

    Indian Academy of Sciences (India)

    CHFB) approach with a pairing+quadrupole+hexadecapole model interaction Hamiltonian the structure of the yrast states of 76,78Kr nuclei is studied up to angular momentum J = 24. Evolution of the shape with spin, and rotation alignment of ...

  17. Spin-orbit and electron correlation effects on the structure of EF3 (E = I, At, and element 117).

    Science.gov (United States)

    Kim, Hyoseok; Choi, Yoon Jeong; Lee, Yoon Sup

    2008-12-18

    Structures and vibrational frequencies of group 17 fluorides EF3 (E = I, At, and element 117) are calculated at the density functional theory (DFT) level of theory using relativistic effective core potentials (RECPs) with and without spin-orbit terms in order to investigate the effects of spin-orbit interactions and electron correlations on the structures and vibrational frequencies of EF3. Various tests imply that spin-orbit and electron correlation effects estimated presently from Hartree-Fock (HF) and DFT calculations with RECPs with and without spin-orbit terms are quite reasonable. Spin-orbit and electron correlation effects generally increase bond lengths and/or angles in both C2v and D3h structures. For IF3, the C2v structure is a global minimum, and the D3h structure is a second-order saddle point in both HF and DFT calculations with and without spin-orbit interactions. Spin-orbit effects for IF3 are negligible in comparison to electron correlation effects. The D3h global minimum is the only minimum structure for (117)F3 in all RECP calculations, and the C2v structure is neither a local minimum nor a saddle point. In the case of AtF3, the C2v structure is found to be a local minimum in all RECP calculations without spin-orbit terms, and the D3h structure becomes a local minimum at the DFT level of theory with and without spin-orbit interactions. In the HF calculation with spin-orbit terms, the D3h structure of AtF3 is a second-order saddle point. AtF3 is a borderline case between the valence-shell-electron-pair-repulsion (VSEPR) structure of IF3 and the non-VSEPR structure of (117)F3. Relativistic effects, including scalar relativistic and spin-orbit effects, and electron correlation effects together or separately stabilize the D3h structures more than the C2v structures. As a result, one may suggest that the VSEPR predictions agree very well with the structures optimized by the nonrelativistic HF level of theory even for heavy-atom molecules but not so

  18. Electron spin transition causing structure transformations of earth's interiors under high pressure

    Science.gov (United States)

    Yamanaka, T.; Kyono, A.; Kharlamova, S.; Alp, E.; Bi, W.; Mao, H.

    2012-12-01

    To elucidate the correlation between structure transitions and spin state is one of the crucial problems for understanding the geophysical properties of earth interiors under high pressure. High-pressure studies of iron bearing spinels attract extensive attention in order to understand strong electronic correlation such as the charge transfer, electron hopping, electron high-low spin transition, Jahn-Teller distortion and charge disproponation in the lower mantle or subduction zone [1]. Experiment Structure transitions of Fe3-xSixO4, Fe3-xTixO4 Fe3-xCrxO4 spinel solid solution have been investigated at high pressure up to 60 GPa by single crystal and powder diffraction studies using synchrotron radiation with diamond anvil cell. X-ray emission experiment (XES) at high pressure proved the spin transition of Fe-Kβ from high spin (HS) to intermediate spin state (IS) or low spin state (LS). Mössbauer experiment and Raman spectra study have been also conducted for deformation analysis of Fe site and confirmation of the configuration change of Fe atoms. Jahn-Teller effect A cubic-to-tetragonal transition under pressure was induced by Jahn-Teller effect of IVFe2+ (3d6) in the tetrahedral site of Fe2TiO4 and FeCr2O4, providing the transformation from 43m (Td) to 42m (D2d). Tetragonal phase is formed by the degeneracy of e orbital of Fe2+ ion. Their c/a ratios are c/adisordered in the M2 site. At pressures above 53 GPa, Fe2TiO4 structure further transforms to Pmma. This structure change results in the order-disorder transition [2]. New structure of Fe2SiO4 The spin transition exerts an influence to Fe2SiO4 spinel structure and triggers two distinct curves of the lattice constant in the spinel phase. The reversible structure transition from cubic to pseudo-rhombohedral phase was observed at about 45 GPa. This transition is induced by the 20% shrinkage of ionic radius of VIFe2+at the low sin state. Laser heating experiment at 1500 K has confirmed the decomposition from the

  19. Structural Disorder and Magnetism in the Spin-Gapless Semiconductor CoFeCrAl

    Science.gov (United States)

    2016-08-24

    AIP ADVANCES 6, 056304 (2016) Structural disorder and magnetism in the spin-gapless semiconductor CoFeCrAl Renu Choudhary,1,2 Parashu Kharel,3 Shah R... semiconductor CoFeCrAl into a half- metallic ferrimagnet and increases the half-metallic band gap by 0.12 eV. Compared CoFeCrAl, the moment of...INTRODUCTION Spin-gapless semiconductors (SGS) have recently attracted much attention as nanoelectronic materials with high carrier mobility and good

  20. Structure of high-spin isomers in trans-lead nuclei

    International Nuclear Information System (INIS)

    Dracoulis, G.D.

    1990-01-01

    The structure of core-excited high-spin isomers in the N ≤ 126 isotopes of At, Rn and Fr is reviewed. New results for high-spin states in 211 Rn and 212 Rn, approaching the limit of the available angular momentum from the valence particles, are presented. The recurring experimental feature is decay by very enhanced E3 transitions. These, and other properties are explained in a natural way by inclusion of particle-octupole vibration coupling, in a semi-empirical shell model. The deformed independent particle model is not successful in explaining these features. 40 refs., 4 tabs., 11 figs

  1. Measurement of the spin structure of the neutron using polarised deep inelastic scattering

    Science.gov (United States)

    Kaiser, Ralf Bernd

    The measurement of the spin structure function g1p of the proton and its integral Γ1p by the EMC experiment at C scERN in 1988 indicated that only 12% ± 17% of the proton spin is carried by quarks. This unexpected result-the so called 'spin crisis'-lead to a series of new experimental proposals. One of these, the H scERMES experiment, uses the polarised positron beam of the H scERA accelerator together with a polarised internal gas target of hydrogen, deuterium or 3He for the study of the spin structure of the nucleon. The scattered positrons and other products of the reaction are detected in a forward spectrometer with large acceptance. This thesis focuses on three topics, after a review of the relevant theory and an overview of the H scERMES experiment: The H scERMES transition radiation detector (TRD), which is used to distinguish high energy positrons from hadrons, the H scERMES particle identification (PID) system and the measurement of the spin structure function g1n of the neutron. The H scERMES TRD is the main Canadian contribution to the apparatus of the experiment. The H scERMES PID system allows the identification of positrons from deep inelastic scattering with an efficiency of 99% and a hadron contamination of less than 0.5%. The first physics result from the 1995 H scERMES data is the measurement of the spin structure function g1n(x) of the neutron. The value of the resulting integral Γ1n=∫01g1n(x)/ dx confirms previous measurements at SLAC and violates the Ellis-Jaffe sum rule by about one sigma. The contribution of the quarks to the spin of the neutron can be calculated in the framework of the quark parton model to be 37 ± 16%, indicating that less than half of the spin of the neutron is carried by quarks.

  2. Self-similar spectral structures and edge-locking hierarchy in open-boundary spin chains

    International Nuclear Information System (INIS)

    Haque, Masudul

    2010-01-01

    For an anisotropic Heisenberg (XXZ) spin chain, we show that an open boundary induces a series of approximately self-similar features at different energy scales, high up in the eigenvalue spectrum. We present a nonequilibrium phenomenon related to this fractal structure, involving states in which a connected block near the edge is polarized oppositely to the rest of the chain. We show that such oppositely polarized blocks can be 'locked' to the edge of the spin chain and that there is a hierarchy of edge-locking effects at various orders of the anisotropy. The phenomenon enables dramatic control of quantum-state transmission and magnetization control.

  3. Measurement of the Spin Structure of the Deuteron in the DIS Region

    CERN Document Server

    Ageev, E.S.; Alexandrov, Yu.; Alexeev, G.D.; Amoroso, A.; Badelek, B.; Balestra, F.; Ball, J.; Baum, G.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Burtin, E.; Bussa, M.P.; Bytchkov, V.N.; Cerini, L.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.A.; Costa, S.; Crespo, M.L.; d'Hose, N.; Dalla Torre, S.; Dasgupta, S.S.; De Masi, R.; Dedek, N.; Denisov, O.Yu.; Dhara, L.; Diaz Kavka, V.; Dinkelbach, A.M.; Dolgopolov, A.V.; Donskov, S.V.; Dorofeev, V.A.; Doshita, N.; Duic, V.; Dunnweber, W.; Ehlers, J.; Eversheim, P.D.; Eyrich, W.; Fabro, M.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger, M., Jr.; Fischer, H.; Franz, J.; Friedrich, J.M.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.M.; Grajek, O.; Grasso, A.; Grube, B.; Grunemaier, A.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.H.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Ijaduola, R.B.; Ilgner, C.; Ioukaev, A.I.; Ishimoto, S.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N.I.; Kabuss, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Khomutov, N.V.; Kisselev, Yu.; Klein, F.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Komissarov, E.V.; Kondo, K.; Konigsmann, Kay; Konoplyannikov, A.K.; Konorov, I.; Konstantinov, V.F.; Korentchenko, A.S.; Korzenev, A.; Kotzinian, A.M.; Koutchinski, N.A.; Kowalik, K.; Kravchuk, N.P.; Krivokhizhin, G.V.; Kroumchtein, Z.V.; Kuhn, R.; Kunne, F.; Kurek, K.; Ladygin, M.E.; Lamanna, M.; Le Goff, J.M.; Leberig, M.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Manuilov, I.V.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Matsuda, T.; Maximov, A.N.; Medved, K.S.; Meyer, W.; Mielech, A.; Mikhailov, Yu.V.; Moinester, M.A.; Nahle, O.; Nassalski, J.; Neliba, S.; Neyret, D.P.; Nikolaenko, V.I.; Nozdrin, A.A.; Obraztsov, V.F.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Pereira, H.D.; Peshekhonov, D.V.; Peshekhonov, V.D.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polyakov, V.A.; Popov, A.A.; Pretz, J.; Quintans, C.; Ramos, S.; Rebourgeard, P.C.; Reicherz, G.; Reymann, J.; Rith, K.; Rojdestvenski, A.M.; Rondio, E.; Sadovski, A.B.; Saller, E.; Samoylenko, V.D.; Sandacz, A.; Sapozhnikov, M.G.; Savin, Igor A.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, L.; Schmitt, H.; Shevchenko, O.Yu.; Shishkin, A.A.; Siebert, H.; Sinha, L.; Sissakian, A.N.; Skachkova, A.; Slunecka, M.; Smirnov, G.I.; Sugonyaev, V.P.; Srnka, A.; Stinzing, F.; Stolarski, M.; Sulc, M.; Sulej, R.; Takabayashi, N.; Tchalishev, V.V.; Thers, D.; Tessarotto, F.; Teufel, A.; Tkatchev, L.G.; Toeda, T.; Tretyak, V.I.; Trusov, Sergey V.; Varanda, M.; Virius, M.; Vlassov, N.V.; Wagner, M.; Walcher, T.; Webb, R.; Weise, E.; Weitzel, Q.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wislicki, W.; Zanetti, A.M.; Zaremba, K.; Zhao, J.; Ziegler, R.; Zvyagin, A.

    2005-01-01

    We present a new measurement of the longitudinal spin asymmetry A_1^d and the spin-dependent structure function g_1^d of the deuteron in the range 1 GeV^2 < Q^2 < 100 GeV^2 and 0.004< x <0.7. The data were obtained by the COMPASS experiment at CERN using a 160 GeV polarised muon beam and a large polarised 6-LiD target. The results are in agreement with those from previous experiments and improve considerably the statistical accuracy in the region 0.004 < x < 0.03.

  4. Helicity in proton–proton elastic scattering and the spin structure of the pomeron

    Directory of Open Access Journals (Sweden)

    Carlo Ewerz

    2016-12-01

    Full Text Available We discuss different models for the spin structure of the nonperturbative pomeron: scalar, vector, and rank-2 symmetric tensor. The ratio of single-helicity-flip to helicity-conserving amplitudes in polarised high-energy proton–proton elastic scattering, known as the complex r5 parameter, is calculated for these models. We compare our results to experimental data from the STAR experiment. We show that the spin-0 (scalar pomeron model is clearly excluded by the data, while the vector pomeron is inconsistent with the rules of quantum field theory. The tensor pomeron is found to be perfectly consistent with the STAR data.

  5. Effect of Spin Transition onComposition and Seismic Structure of the Lower Mantle

    Science.gov (United States)

    Wu, Z.

    2015-12-01

    Spin transition of iron in ferropericlase (Fp) causes a significant softening in bulk modulus [e.g.,1,2], which leads to unusual dVP/dT>0. Because dVP/dT>0 in Fp cancels out with dVP/dTMao, Z., Marquardt, H., 2013. . Rev Geophys 51, 244-275 (2013). [3] Wu, Z.Q., Wentzcovitch, R.M., 2014. Spin crossover in ferropericlase and velocity heterogeneities in the lower mantle. Proc. Natl. Acad. Sci. U. S. A. 111, 10468-10472. [4] Zhao, D.P., 2007. Seismic images under 60 hotspots: Search for mantle plumes. Gondwana Res 12, 335-355. [5] van der Hilst, R.D., Karason, H., 1999. Science 283, 1885-1888. [6] Huang,C., Leng, W., Wu, Z. Q., 2015. Iron-spin transition controls structure and stability of LLSVPs in the lower mantle, Earth Planet. Sci. Lett. 423, 173-181.

  6. Exploring Nucleon Spin Structure Through Neutrino Neutral-Current Interactions in MicroBooNE

    Energy Technology Data Exchange (ETDEWEB)

    Woodruff, Katherine [New Mexico State U.

    2017-02-02

    The net contribution of the strange quark spins to the proton spin, $\\Delta s$, can be determined from neutral current elastic neutrino-proton interactions at low momentum transfer combined with data from electron-proton scattering. The probability of neutrino-proton interactions depends in part on the axial form factor, which represents the spin structure of the proton and can be separated into its quark flavor contributions. Low momentum transfer neutrino neutral current interactions can be measured in MicroBooNE, a high-resolution liquid argon time projection chamber (LArTPC) in its first year of running in the Booster Neutrino Beamline at Fermilab. The signal for these interactions in MicroBooNE is a single short proton track. We present our work on the automated reconstruction and classification of proton tracks in LArTPCs, an important step in the determination of neutrino- nucleon cross sections and the measurement of $\\Delta s$.

  7. Structural and energetic hot-spots for the interaction between a ladder-like polycyclic ether and the anti-ciguatoxin antibody 10C9Fab.

    Science.gov (United States)

    Ui, Mihoko; Tanaka, Yoshikazu; Tsumuraya, Takeshi; Fujii, Ikuo; Inoue, Masayuki; Hirama, Masahiro; Tsumoto, Kouhei

    2011-03-01

    The mechanism by which anti-ciguatoxin antibody 10C9Fab recognizes a fragment of ciguatoxin CTX3C (CTX3C-ABCDE) was investigated by mutational analysis based on structural data. 10C9Fab has an extraordinarily large and deep antigen-binding pocket at the center of its variable region. We mutated several residues located at the antigen-binding pocket to Ala, and kinetic analysis of the interactions between the mutant proteins and the antigen fragment was performed. The results indicate that some residues associated with the rigid antigen-binding pocket are structural hot-spots and that L-N94 is an energetic hot-spot for association of the antibody with the antigen fragment CTX3C-ABCDE, suggesting the importance of structural complementarity and energetic hot-spot interactions for specific recognition of polycyclic ethers.

  8. Spin coated versus dip coated electrochromic tungsten oxide films: Structure, morphology, optical and electrochemical properties

    International Nuclear Information System (INIS)

    Deepa, M.; Saxena, T.K.; Singh, D.P.; Sood, K.N.; Agnihotry, S.A.

    2006-01-01

    A sol-gel derived acetylated peroxotungstic acid sol encompassing 4 wt.% of oxalic acid dihydrate (OAD) has been employed for the deposition of tungsten oxide (WO 3 ) films by spin coating and dip coating techniques, in view of smart window applications. The morphological and structural evolution of the as-deposited spin and dip coated films as a function of annealing temperature (250 and 500 o C) has been examined and compared by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). A conspicuous feature of the dip coated film (annealed at 250 o C) is that its electrochromic and electrochemical properties ameliorate with cycling without degradation in contrast to the spin coated film for which these properties deteriorate under repetitive cycling. A comparative study of spin and dip coated nanostructured thin films (annealed at 250 o C) revealed a superior performance for the cycled dip coated film in terms of higher transmission modulation and coloration efficiency in solar and photopic regions, faster switching speed, higher electrochemical activity as well as charge storage capacity. While the dip coated film could endure 2500 color-bleach cycles, the spin coated film could sustain only a 1000 cycles. The better cycling stability of the dip coated film which is a repercussion of a balance between optimal water content, porosity and grain size hints at its potential for electrochromic window applications

  9. Recent COMPASS results on the nucleon longitudinal spin structure and QCD fits

    Directory of Open Access Journals (Sweden)

    Andrieux Vincent

    2014-01-01

    Full Text Available The latest measurements of the proton longitudinal spin structure function, ɡ1p, in the deep inelastic (DIS regime are presented. They improve the statistical accuracy of the existing data and extend the kinematic domain to a lower value of x and higher values of Q2. A global NLO QCD fit of all ɡ1 world data on the proton, deuteron and neutron has been achieved. The results give a quantification of the quark spin contribution to the nucleon spin, 0.26 < ΔΣ < 0.34 at 3 (GeV/c2 in M̅S̅ scheme. The errors are dominated by the uncertainty on the shape of the functional forms assumed in the fit. A new verification of the fundamental Bjorken sum rule is obtained at a 9% level, using only COMPASS ɡ1 proton and deuteron measurements. Preliminary results of a reevaluation of the gluon polarization Δɡ/ɡ are presented. The analysis is based on double spin asymmetry of high-pT hadron production cross-sections in the DIS regime. A positive value of 〈Δɡ/ɡ〉 = 0.113 ± 0.038 ± 0.035 is obtained at leading order at x ~ 0.1. In parallel, the double spin asymmetry in the photoproduction regime is also studied. Finally, preliminary results on quark fragmentation functions into pions extracted from a LO fit of pion multiplicities in semi-inclusive DIS are presented.

  10. Insights on the Structural Details of Endonuclease EcoRI-DNA Complexes by Electron Spin Resonance

    Science.gov (United States)

    Sarver, Jessica

    2009-03-01

    Pulsed electron spin resonance (ESR) was used to probe the binding specificity of EcoRI, a restriction endonuclease. Using site-directed spin labeling, a nitroxide side chain was incorporated into the protein, enabling the use of ESR to study structural details of EcoRI. Distance measurements were performed on EcoRI mutants when bound to varying sequences of DNA using the Double Electron-Electron Resonance experiment. These distances demonstrated that the average structure in the arm regions of EcoRI, thought to play a major role in binding specificity, is the same when the protein binds to different sequences of DNA. Also, it was determined that the arms exhibit higher flexibility when bound to sequences other than the specific sequence due to the larger distance distributions acquired from these spin labeled complexes. Molecular dynamics (MD) simulations were performed on the spin-label-modified specific EcoRI-DNA crystal structure to model the average nitroxide orientation. The distance distributions from MD were found to be narrower than experiment, indicating the need for a more rigorous sampling of the nitroxide conformers in silico.

  11. Extraordinary Spin-Wave Thermal Conductivity in Low-Dimensional Copper Oxides

    Science.gov (United States)

    2015-01-23

    excitations of spin degrees of freedom. We measmed for the first time the magnon -phonon coupling parameter of a spin-ladder compound over a wide temperatme...the first time the magnon -phonon coupling parameter of a spin-ladder compound over a wide temperature range. We developed advances in the analysis of...Scientific Instruments, (10 2014): 104903. doi: 10.1063/1.4897622 Gregory T. Hohensee, R. B. Wilson, Joseph P. Feser, David G. Cahill. Magnon -phonon

  12. Electronic properties of mesoscopic graphene structures: Charge confinement and control of spin and charge transport

    Energy Technology Data Exchange (ETDEWEB)

    Rozhkov, A.V., E-mail: arozhkov@gmail.co [Advanced Science Institute, RIKEN, Wako-shi, Saitama, 351-0198 (Japan); Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, 125412, Moscow (Russian Federation); Giavaras, G. [Advanced Science Institute, RIKEN, Wako-shi, Saitama, 351-0198 (Japan); Bliokh, Yury P. [Advanced Science Institute, RIKEN, Wako-shi, Saitama, 351-0198 (Japan); Department of Physics, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Freilikher, Valentin [Advanced Science Institute, RIKEN, Wako-shi, Saitama, 351-0198 (Japan); Department of Physics, Bar-Ilan University, Ramat-Gan 52900 (Israel); Nori, Franco [Advanced Science Institute, RIKEN, Wako-shi, Saitama, 351-0198 (Japan); Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States)

    2011-06-15

    This brief review discusses electronic properties of mesoscopic graphene-based structures. These allow controlling the confinement and transport of charge and spin; thus, they are of interest not only for fundamental research, but also for applications. The graphene-related topics covered here are: edges, nanoribbons, quantum dots, pn-junctions, pnp-structures, and quantum barriers and waveguides. This review is partly intended as a short introduction to graphene mesoscopics.

  13. Analysis and demonstration of single-passband response and tuning characteristics in a chirped ladder interferometric filter for a widely tunable laser diode.

    Science.gov (United States)

    Jeong, Seok-Hwan; Matsuo, Shinji; Yoshikuni, Yuzo; Segawa, Toru; Ohiso, Yoshitaka; Suzuki, Hiroyuki

    2005-10-01

    We have designed and demonstrated a chirped ladder-type tunable filter and discussed its potential application for a tunable diode laser. A ladder interferometric filter normally has a periodic passband, which makes it impossible to stabilize laser oscillation frequency. To overcome this drawback, we have designed, fabricated, and characterized a novel chirped tunable ladder filter. We have successfully demonstrated a single-passband response in the fabricated device. Furthermore, a tuning operation of more than 30 nm was achieved by introducing a current injection structure and optimizing electrode lengths at each single-stage ladder interferometer.

  14. Nuclear structure at high spin using multidetector gamma array and ...

    Indian Academy of Sciences (India)

    2014-04-05

    Apr 5, 2014 ... A multidetector gamma array (GDA), for studying nuclear structure was built with ancillary devices namely gamma multiplicity filter and charged particle detector array. This facility was designed for in-beam gamma spectroscopy measurements in fusion evaporation reactions at Inter-University Accelerator ...

  15. Structural and magnetic anomalies among the spin-chain ...

    Indian Academy of Sciences (India)

    Unknown

    the compound, Ca3CoIrO6, exhibits magnetic frustration effects around 30–50 K in the ac and dc M data, but without getting influenced by the application of magnetic fields as high as even 40 kOe, however without showing PDA structural features.14 A common feature between these two compounds is that the ac magnetic ...

  16. Spin-wave-induced spin torque in Rashba ferromagnets

    Science.gov (United States)

    Umetsu, Nobuyuki; Miura, Daisuke; Sakuma, Akimasa

    2015-05-01

    We study the effects of Rashba spin-orbit coupling on the spin torque induced by spin waves, which are the plane-wave dynamics of magnetization. The spin torque is derived from linear-response theory, and we calculate the dynamic spin torque by considering the impurity-ladder-sum vertex corrections. This dynamic spin torque is divided into three terms: a damping term, a distortion term, and a correction term for the equation of motion. The distorting torque describes a phenomenon unique to the Rashba spin-orbit coupling system, where the distorted motion of magnetization precession is subjected to the anisotropic force from the Rashba coupling. The oscillation mode of the precession exhibits an elliptical trajectory, and the ellipticity depends on the strength of the nesting effects, which could be reduced by decreasing the electron lifetime.

  17. Nitration Study of Cyclic Ladder Polyphenylsilsesquioxane

    Directory of Open Access Journals (Sweden)

    LIANG Jia-xiang

    2017-05-01

    Full Text Available Several nitration reagents including fuming nitric acid, HNO3-H2SO4, KNO3-H2SO4, HNO3-KNO3, CH3COOH-KNO3, (CH3CO2O-HNO3 were used to nitrate cyclic ladder polyphenylsilsesquioxane (CL-PPSQ in different conditions in order to enhance the compatibility of the CL-PPSQ in polymers, the NO2-PPSQ was obtained. FTIR, element analysis, GPC, TGA and 1H NMR were used to characterize the structures of the nitrated products. The results show that the nitrating abilities of the fuming nitric acid, HNO3-H2SO4 and KNO3-H2SO4 are very strong. Many nitro groups can be linked with phenyl groups in CL-PPSQ, but with low molecular mass, fracture occurs in siloxane segment. However, the Mn of the product NO2-PPSQ sharply drops by 50% compared with that of CL-PPSQ, so the nitration reagents can break the cyclic structure of CL-PPSQ. The nitrating reagents of HNO3-KNO3 and CH3COOH-KNO3 have no nitration effects on CL-PPSQ. At last, NO2-CL-PPSQ was prepared using (CH3CO2O-HNO3 because of the moderate nitration process and ability. The cyclic structure of PPSQ is remained, although the number of —NO2 group is not too much. At the same time, the nitration mechanism using different nitration reagents was analyzed. A certain amount of NO2+, which is a kind of activator owning strong nitration ability, can be found in the fuming nitric acid and H2SO4-HNO3(KNO3 systems. As to the (CH3CO2O-HNO3 system, the main activator is CH3COONO2.

  18. A bifunctional spin label reports the structural topology of phospholamban in magnetically-aligned bicelles

    Science.gov (United States)

    McCaffrey, Jesse E.; James, Zachary M.; Svensson, Bengt; Binder, Benjamin P.; Thomas, David D.

    2016-01-01

    We have applied a bifunctional spin label and EPR spectroscopy to determine membrane protein structural topology in magnetically-aligned bicelles, using monomeric phospholamban (PLB) as a model system. Bicelles are a powerful tool for studying membrane proteins by NMR and EPR spectroscopies, where magnetic alignment yields topological constraints by resolving the anisotropic spectral properties of nuclear and electron spins. However, EPR bicelle studies are often hindered by the rotational mobility of monofunctional Cys-linked spin labels, which obscures their orientation relative to the protein backbone. The rigid and stereospecific TOAC label provides high orientational sensitivity but must be introduced via solid-phase peptide synthesis, precluding its use in large proteins. Here we show that a bifunctional methanethiosulfonate spin label attaches rigidly and stereospecifically to Cys residues at i and i + 4 positions along PLB's transmembrane helix, thus providing orientational resolution similar to that of TOAC, while being applicable to larger membrane proteins for which synthesis is impractical. Computational modeling and comparison with NMR data shows that these EPR experiments provide accurate information about helix tilt relative to the membrane normal, thus establishing a robust method for determining structural topology in large membrane proteins with a substantial advantage in sensitivity over NMR.

  19. A NEW METHOD FOR EXTRACTING SPIN-DEPENDENT NEUTRON STRUCTURE FUNCTIONS FROM NUCLEAR DATA

    Energy Technology Data Exchange (ETDEWEB)

    Kahn, Y.F.; Melnitchouk, W.

    2009-01-01

    High-energy electrons are currently the best probes of the internal structure of nucleons (protons and neutrons). By collecting data on electrons scattering off light nuclei, such as deuterium and helium, one can extract structure functions (SFs), which encode information about the quarks that make up the nucleon. Spin-dependent SFs, which depend on the relative polarization of the electron beam and the target nucleus, encode quark spins. Proton SFs can be measured directly from electron-proton scattering, but those of the neutron must be extracted from proton data and deuterium or helium-3 data because free neutron targets do not exist. At present, there is no reliable method for accurately determining spin-dependent neutron SFs in the low-momentum-transfer regime, where nucleon resonances are prominent and the functions are not smooth. The focus of this study was to develop a new method for extracting spin-dependent neutron SFs from nuclear data. An approximate convolution formula for nuclear SFs reduces the problem to an integral equation, for which a recursive solution method was designed. The method was then applied to recent data from proton and deuterium scattering experiments to perform a preliminary extraction of spin-dependent neutron SFs in the resonance region. The extraction method was found to reliably converge for arbitrary test functions, and the validity of the extraction from data was verifi ed using a Bjorken integral, which relates integrals of SFs to a known quantity. This new information on neutron structure could be used to assess quark-hadron duality for the neutron, which requires detailed knowledge of SFs in all kinematic regimes.

  20. Bloch spin waves and emergent structure in protein folding with HIV envelope glycoprotein as an example

    Science.gov (United States)

    Dai, Jin; Niemi, Antti J.; He, Jianfeng; Sieradzan, Adam; Ilieva, Nevena

    2016-03-01

    We inquire how structure emerges during the process of protein folding. For this we scrutinize collective many-atom motions during all-atom molecular dynamics simulations. We introduce, develop, and employ various topological techniques, in combination with analytic tools that we deduce from the concept of integrable models and structure of discrete nonlinear Schrödinger equation. The example we consider is an α -helical subunit of the HIV envelope glycoprotein gp41. The helical structure is stable when the subunit is part of the biological oligomer. But in isolation, the helix becomes unstable, and the monomer starts deforming. We follow the process computationally. We interpret the evolving structure both in terms of a backbone based Heisenberg spin chain and in terms of a side chain based XY spin chain. We find that in both cases the formation of protein supersecondary structure is akin the formation of a topological Bloch domain wall along a spin chain. During the process we identify three individual Bloch walls and we show that each of them can be modelled with a precision of tenths to several angstroms in terms of a soliton solution to a discrete nonlinear Schrödinger equation.

  1. Experimental study on the spin-orbit coupling property in low-dimensional semiconductor structures

    International Nuclear Information System (INIS)

    Zhao, Hongming

    2010-01-01

    The spin-orbit coupling and optical properties have been studied in several low-dimensional semiconductor structures. First, the spin dynamics in (001) GaAs/AlGaAs two-dimensional electron gas was investigated by time resolved Kerr rotation technique under a transverse magnetic field. The in-plane spin lifetime is found to be anisotropic. The results show that the electron density in two-dimensional electron gas channel strongly affects the Rashba spin-orbit coupling. Then, a large anisotropy of the magnitude of in-plane conduction electron g factor in asymmetric (001) GaAs/AlGaAs QWs was observed and its tendency of temperature dependence was studied. Second, the experimental study of the in-plane-orientation dependent spin splitting in the C(0001) GaN/AlGaN two-dimensional electron gas at room temperature was reported. The measurement of circular photo-galvanic effect current clearly shows the isotropic in-plane spin splitting in this system for the first time. Third, the first measurement of conduction electron g factor in GaAsN at room temperature was done by using time resolved Kerr rotation technique. It demonstrates that the g factor can be modified drastically by introducing a small amount of nitrogen in GaAs bulk. Finally, the optical characteristic of indirect type II transition in a series of size and shape-controlled linear CdTe/CdSe/CdTe heterostructure nano-rods was studied by steady-state and time resolved photoluminescence. Results show the steady transfer from the direct optical transition (type I) within CdSe to the indirect transition (type II) between CdSe/CdTe as the length of the nano-rods increases. (author)

  2. 29 CFR 1910.26 - Portable metal ladders.

    Science.gov (United States)

    2010-07-01

    ... and taken out of service until repaired by either maintenance department or the manufacturer. (3) Use... are designed as a one-man working ladder based on a 200-pound load. (iii) The ladder base section must...

  3. The E142 SLAC experiment: measurement of the neutron gn1(x) spin structure function

    International Nuclear Information System (INIS)

    Roblin, Y.

    1995-01-01

    This thesis describes the E142 experiment which has been carried out at the Stanford Linear Accelerator (SLAC), USA, from October to December 1992. This experiment of polarized inelastic scattering of a 22.6 GeV electron beam on a polarized helium 3 target has allowed the first measurement of the neutron g n 1 (x) spin structure function. The knowledge of this structure function gives informations on the nucleon spin structure. On the other hand, the g n 1 (x) structure function integral value on the 0 2 mean value of 2 GeV 2 after some extrapolations. This value is at about two standard deviations away from the theoretical predictions of the Ellis-Jaffe rule. Thanks to the existing experimental results for the proton (E143 experiment), the Bjorken sum rule has been precisely tested and is perfectly compatible with the theoretical value. The results have allowed to estimate the nucleon spin fraction carried by the quarks. (J.S.). 86 refs., 58 figs., 13 tabs

  4. Spin-mapping of coal structures with ESE and ENDOR

    Energy Technology Data Exchange (ETDEWEB)

    Belford, R.L.; Clarkson, R.B.

    1990-12-01

    To ENDOR and ESE we have added another advanced EPR technique. VHF-EPR, as a tool with which to observe coal molecular structure, especially organic sulfur. We have constructed a unique VHF EPR instrument operating at the W-band (96 Ghz), one of only two such instruments in the world, and the only one studying coal. We are employing this instrument, as well as collaborating with scientists at Cornell University, who have a 250 GHz spectrometer, to develop a clearer understanding of the relationships between the VHF EPR spectra we observe from Illinois coal and the organic sulfur species present in it. Efforts in this quarter focussed on three area: recruitment of personnel (especially a new postdoctoral fellow) to join the coal research team work on improving the W-band spectrometer, and studies of vitrinite, sporinite, and fusinite macerals at G-band (250 GHz). All three areas have shown good progress. This report will discuss in detail the main features of the W-band instrument, stressing its unique engineering features as well as comparing it to the few other instruments in the world operating in the VHF frequency range (90--250 GHz). Preliminary analysis of the 250 GHz data on macerals obtained by density gradient centrifugation from an Illinois {number sign}6 coal gives the first indication that at the very highest frequencies, there may be a separation of the heteroatom VHF EPR signals into a sulfur and on oxygen-containing component. 15 refs., 9 figs., 1 tab.

  5. Spin structures on algebraic curves and their applications in string theories

    International Nuclear Information System (INIS)

    Ferrari, F.

    1990-01-01

    The free fields on a Riemann surface carrying spin structures live on an unramified r-covering of the surface itself. When the surface is represented as an algebraic curve related to the vanishing of the Weierstrass polynomial, its r-coverings are algebraic curves as well. We construct explicitly the Weierstrass polynomial associated to the r-coverings of an algebraic curve. Using standard techniques of algebraic geometry it is then possible to solve the inverse Jacobi problem for the odd spin structures. As an application we derive the partition functions of bosonic string theories in many examples, including two general curves of genus three and four. The partition functions are explicitly expressed in terms of branch points apart from a factor which is essentially a theta constant. 53 refs., 4 figs. (Author)

  6. The Static Ladder Problem with Two Sources of Friction

    Science.gov (United States)

    Bennett, Jonathan; Mauney, Alex

    2011-01-01

    The problem of a ladder leaning against a wall in static equilibrium is a classic example encountered in introductory mechanics texts. Most discussions of this problem assume that the static frictional force between the ladder and wall can be ignored. A few authors consider the case where the static friction coefficients between ladder/wall…

  7. 46 CFR 116.438 - Stairtowers, stairways, ladders, and elevators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Stairtowers, stairways, ladders, and elevators. 116.438... AND ARRANGEMENT Fire Protection § 116.438 Stairtowers, stairways, ladders, and elevators. (a) A vessel... the requirements for stairways, ladders, and elevators in § 72.05-20 of this chapter. (b) Materials...

  8. Quantifying Ladder Fuels: A New Approach Using LiDAR

    Science.gov (United States)

    Heather Kramer; Brandon Collins; Maggi Kelly; Scott Stephens

    2014-01-01

    We investigated the relationship between LiDAR and ladder fuels in the northern Sierra Nevada, California USA. Ladder fuels are often targeted in hazardous fuel reduction treatments due to their role in propagating fire from the forest floor to tree crowns. Despite their importance, ladder fuels are difficult to quantify. One common approach is to calculate canopy base...

  9. Structure of stable binary neutron star merger remnants: Role of initial spin

    Science.gov (United States)

    Kastaun, W.; Ciolfi, R.; Endrizzi, A.; Giacomazzo, B.

    2017-08-01

    We present general relativistic numerical simulations of binary neutron star (BNS) mergers with different initial spin configurations. We focus on models with stars of mass 1.4 M⊙ each, which employ the equation of state (EOS) by Shen, Horowitz, and Teige, and which result in stable NSs as merger remnants. For comparison, we consider two irrotational equal mass (M =1.35 M⊙) and unequal mass (M =1.29 , 1.42 M⊙ ) BNS models using the APR4 EOS, which result in a supramassive merger remnant. We present visualizations of the fluid flow and temperature distribution and find a strong impact of the spin on vortex structure and nonaxisymmetric deformation. We compute the radial mass distribution and the rotation profile in the equatorial plane using recently developed measures independent of spatial gauge, revealing slowly rotating cores that can be well approximated by the cores of spherical stars. We also study the influence of the spin on the inspiral phase and the gravitational wave (GW) signal. Using a newly developed analysis method, we further show that gravitational waveforms from BNS mergers can exhibit one or more phase jumps after merger, which occur together with minima of the strain amplitude. We provide a natural explanation in terms of the remnant's quadrupole moment, and show that cancellation effects due to phase jumps can have a strong impact on the GW power spectrum. Finally, we discuss the impact of the spin on the amount of ejected matter.

  10. su(1,2) Algebraic Structure of XYZ Antiferromagnetic Model in Linear Spin-Wave Frame

    International Nuclear Information System (INIS)

    Jin Shuo; Xie Binghao; Yu Zhaoxian; Hou Jingmin

    2008-01-01

    The XYZ antiferromagnetic model in linear spin-wave frame is shown explicitly to have an su(1,2) algebraic structure: the Hamiltonian can be written as a linear function of the su(1,2) algebra generators. Based on it, the energy eigenvalues are obtained by making use of the similar transformations, and the algebraic diagonalization method is investigated. Some numerical solutions are given, and the results indicate that only one group solution could be accepted in physics

  11. .sup.57./sup.Fe NMR and spin structure of manganese ferrite

    Czech Academy of Sciences Publication Activity Database

    Štěpánková, H.; Sedlák, B.; Chlan, V.; Novák, Pavel; Šimša, Zdeněk

    2008-01-01

    Roč. 77, č. 9 (2008), 092416/1-092419/4 ISSN 1098-0121 R&D Projects: GA ČR GA202/08/0541; GA ČR GA202/06/0051 Institutional research plan: CEZ:AV0Z10100521 Keywords : NMR * manganese ferrite * spin structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.322, year: 2008

  12. Spin asymmetry Ad1 and the spin-dependent structure function gd1 of the deuteron at low values of x and Q2

    Czech Academy of Sciences Publication Activity Database

    Alexakhin, V.; Alexandrov, Y.; Alexeev, G.; Amoroso, A.; Badelek, B.; Balestra, F.; Ball, J.; Baum, G.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Burtin, E.; Bussa, M.; Bytchkov, V.; Cerini, L.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.; Costa, S.; Crespo, M.; d'Hose, N.; Dalla Torre, S.; Dasgupta, S. S.; De Masi, R.; Dedek, N.; Denisov, O.; Dhara, L.; Diaz Kavka, V.; Dinkelbach, A.; Dolgopolov, A.; Donskov, S.; Dorofeev, V.; Doshita, N.; Duic, V.; Dünnweber, W.; Ehlers, J.; Eversheim, P.; Eyrich, W.; Fabro, M.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger jr., M.; Fischer, H.; Franz, J.; Friedrich, J.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.; Grajek, O.; Grasso, A.; Grube, B.; Grünemaier, A.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Ijaduola, R.; Ilgner, C.; Ioukaev, A.; Ishimoto, S.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N. I.; Kabuss, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G.; Khokhlov, Y.; Khomutov, N.; Kisselev, Y.; Klein, F.; Koblitz, S.; Koivuniemi, J.; Kolosov, V.; Komissarov, E.; Kondo, K.; Königsmann, K.; Konoplyannikov, A.; Konorov, I.; Konstantinov, V.; Korentchenko, A.; Korzenev, A.; Kotzinian, A.; Koutchinski, N.; Kowalik, K.; Kravchuk, N.; Krivokhizhin, G.; Kroumchtein, Z.; Kuhn, R.; Kunne, F.; Kurek, K.; Ladygin, M.; Lamanna, M.; Le Goff, J.; Leberig, M.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.; Manuilov, I.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Matsuda, T.; Maximov, A.; Medved, K.; Meyer, W.; Mielech, A.; Mikhailov, Y.; Moinester, M.; Nähle, O.; Nassalski, J.; Neliba, S.; Neyret, D.; Nikolaenko, V.; Nozdrin, A.; Obraztsov, V.; Olshevsky, A.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Pereira, H.; Peshekhonov, D.; Peshekhonov, V.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polyakov, V.; Popov, A.; Pretz, J.; Quintans, C.; Ramos, S.; Rebourgeard, P.; Reicherz, G.; Reymann, J.; Rith, K.; Rozhdestvensky, A.; Rondio, E.; Sadovski, A.; Saller, E.; Samoylenko, V.; Sandacz, A.; Sans, M.; Sapozhnikov, M.; Savin, I.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, H.; Schmitt, L.; Shevchenko, O.; Shishkin, A.; Siebert, H.; Sinha, L.; Sissakian, A.; Skachkova, A.; Slunecka, M.; Smirnov, G.; Sozzi, F.; Sugonyaev, V.; Srnka, Aleš; Stinzing, F.; Stolarski, M.; Sulc, M.; Sulej, R.; Takabayashi, N.; Tchalishev, V.; Tassarotto, F.; Teufel, A.; Thers, D.; Tkatchev, L.; Toeda, T.; Tretyak, V.; Trousov, S.; Varanda, M.; Virius, M.; Vlassov, N.; Wagner, M.; Webb, R.; Weise, E.; Weitzel, Q.; Wiedner, U.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wislicki, W.; Zanetti, A.; Zaremba, K.; Zhao, J.; Ziegler, R.; Zvyagin, A.

    2007-01-01

    Roč. 647, 5-6 (2007), s. 330-340 ISSN 0370-2693 R&D Projects: GA MŠk(CZ) ME 492 Institutional research plan: CEZ:AV0Z20650511 Keywords : inelastic muon scattering * spin * structure function Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.189, year: 2007

  13. High-spin states in 136La and possible structure change in the N =79 region

    Science.gov (United States)

    Nishibata, H.; Leguillon, R.; Odahara, A.; Shimoda, T.; Petrache, C. M.; Ito, Y.; Takatsu, J.; Tajiri, K.; Hamatani, N.; Yokoyama, R.; Ideguchi, E.; Watanabe, H.; Wakabayashi, Y.; Yoshinaga, K.; Suzuki, T.; Nishimura, S.; Beaumel, D.; Lehaut, G.; Guinet, D.; Desesquelles, P.; Curien, D.; Higashiyama, K.; Yoshinaga, N.

    2015-05-01

    High-spin states in the odd-odd nucleus 136La, which is located close to the β -stability line, have been investigated in the radioactive-beam-induced fusion-evaporation reaction 124Sn(17N,5 n ). The use of the radioactive beam enabled a highly sensitive and successful search for a new isomer [14+,T1 /2=187 (27 ) ns] in 136La. In the A =130 -140 mass region, no such long-lived isomer has been observed at high spin in odd-odd nuclei. The 136La level scheme was revised, incorporating the 14+ isomer and six new levels. The results were compared with pair-truncated shell model (PTSM) calculations which successfully explain the level structure of the π h11 /2⊗ν h11/2 -1 bands in 132La and 134La. The isomerism of the 14+ state was investigated also by a collective model, the cranked Nilsson-Strutinsky (CNS) model, which explains various high-spin structures in the medium-heavy mass region. It is suggested that a new type of collective structure is induced in the PTSM model by the increase of the number of π g7 /2 pairs, and/or in the CNS model by the configuration change associated with the shape change in 136La.

  14. Action–angle variables, ladder operators and coherent states

    International Nuclear Information System (INIS)

    Campoamor-Stursberg, R.; Gadella, M.; Kuru, Ş.; Negro, J.

    2012-01-01

    This Letter is devoted to the building of coherent states from arguments based on classical action–angle variables. First, we show how these classical variables are associated to an algebraic structure in terms of Poisson brackets. In the quantum context these considerations are implemented by ladder type operators and a structure known as spectrum generating algebra. All this allows to generate coherent states and thereby the correspondence of classical–quantum properties by means of the aforementioned underlying structure. This approach is illustrated with the example of the one-dimensional Pöschl–Teller potential system. -- Highlights: ► We study the building of coherent states from classical action–angle variables arguments. ► The classical variables are associated to an algebraic structure in terms of Poisson brackets. ► In the quantum context these considerations are implemented by ladder type operators. ► All this allows to formulate coherent states and the correspondence of classical–quantum properties.

  15. Spin asymmetry $A^d_1$ and the spin-dependent structure function $g^d_1$ of the deuteron at low values of $x$ and $Q^2$

    CERN Document Server

    Ageev, E.S.; Alexandrov, Yu.; Alexeev, G.D.; Amoroso, A.; Badelek, B.; Balestra, F.; Ball, J.; Baum, G.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Burtin, E.; Bussa, M.P.; Bytchkov, V.N.; Cerini, L.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.A.; Costa, S.; Crespo, M.L.; d'Hose, N.; Dalla Torre, S.; Dasgupta, S.S.; De Masi, R.; Dedek, N.; Denisov, O.Yu.; Dhara, L.; Diaz Kavka, V.; Dinkelbach, A.M.; Dolgopolov, A.V.; Donskov, S.V.; Dorofeev, V.A.; Doshita, N.; Duic, V.; Dunnweber, W.; Ehlers, J.; Eversheim, P.D.; Eyrich, W.; Fabro, M.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger, M., Jr.; Fischer, H.; Franz, J.; Friedrich, J.M.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.M.; Grajek, O.A.; Grasso, A.; Grube, B.; Grunemaier, A.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.H.; Hermann, R.; He, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Ijaduola, R.B.; Ilgner, C.; Ioukaev, A.I.; Ishimoto, S.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N.I.; Kabuss, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Khomutov, N.V.; Kisselev, Yu.; Klein, F.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Komissarov, E.V.; Kondo, K.; Konigsmann, Kay; Konoplyannikov, A.K.; Konorov, I.; Konstantinov, V.F.; Korentchenko, A.S.; Korzenev, A.; Kotzinian, A.M.; Koutchinski, N.A.; Kowalik, K.; Kravchuk, N.P.; Krivokhizhin, G.V.; Kroumchtein, Z.V.; Kuhn, R.; Kunne, F.; Kurek, K.; Ladygin, M.E.; Lamanna, M.; Le Goff, J.M.; Leberig, M.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Manuilov, I.V.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Matsuda, T.; Maximov, A.N.; Medved, K.S.; Meyer, W.; Mielech, A.; Mikhailov, Yu.V.; Moinester, M.A.; Nahle, O.; Nassalski, J.; Neliba, S.; Neyret, D.P.; Nikolaenko, V.I.; Nozdrin, A.A.; Obraztsov, V.F.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Pereira, H.D.; Peshekhonov, D.V.; Peshekhonov, V.D.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polyakov, V.A.; Popov, A.A.; Pretz, J.; Quintans, C.; Ramos, S.; Rebourgeard, P.C.; Reicherz, G.; Reymann, J.; Rith, K.; Rozhdestvensky, A.M.; Rondio, E.; Sadovski, A.B.; Saller, E.; Samoylenko, V.D.; Sandacz, A.; Sans, M.; Sapozhnikov, M.G.; Savin, Igor A.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, H.; Schmitt, L.; Shevchenko, O.Yu.; Shishkin, A.A.; Siebert, H.-W.; Sinha, L.; Sissakian, A.N.; Skachkova, A.; Slunecka, M.; Smirnov, G.I.; Sozzi, F.; Sugonyaev, V.P.; Srnka, A.; Stinzing, F.; Stolarski, M.; Sulc, M.; Sulej, R.; Takabayashi, N.; Tchalishev, V.V.; Tessarotto, F.; Teufel, A.; Thers, D.; Tkatchev, L.G.; Toeda, T.; Tretyak, V.I.; Trusov, Sergey V.; Varanda, M.; Virius, M.; Vlassov, N.V.; Wagner, M.; Webb, R.; Weise, E.; Weitzel, Q.; Wiedner, U.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wislicki, W.; Zanetti, A.M.; Zaremba, K.; Zhao, J.; Ziegler, R.; Zvyagin, A.

    2007-01-01

    We present a precise measurement of the deuteron longitudinal spin asymmetry $A_1^d$ and of the deuteron spin-dependent structure function $g_1^d$ at $Q^2 < $ 1~(GeV/$c$)$^2$ and $4\\cdot$10$^{-5} < x < $~2.5$\\cdot$10$^{-2}$ based on the data collected by the COMPASS experiment at CERN during the years 2002 and 2003. The statistical precision is tenfold better than that of the previous measurement in this region. The measured $A_1^d$ and $g_1^d$ are found to be consistent with zero in the whole range of $x$.

  16. 29 CFR 1915.72 - Ladders.

    Science.gov (United States)

    2010-07-01

    ... nailed to each rail with five 10d common wire nails or fastened with through bolts or other fasteners of... split side rails, or other faulty or defective construction is prohibited. When ladders with such... bolted to each rail. The combined cross sectional area of the cleats shall be not less than the cross...

  17. Fermion-boson scattering in ladder approximation

    International Nuclear Information System (INIS)

    Jafarov, R.G.; Hadjiev, S.A.

    1992-10-01

    A method of calculation of forward scattering amplitude for fermions and scalar bosons with exchanging of scalar particle is suggested. The Bethe-Salpeter ladder equation for the imaginary part of the amplitude is constructed and a solution in Regge asymptotical form is found and the corrections to the amplitude due to the exit from mass shell are calculated. (author). 8 refs

  18. Bimodule structure in the periodic gℓ(1|1) spin chain

    International Nuclear Information System (INIS)

    Gainutdinov, A.M.; Read, N.; Saleur, H.

    2013-01-01

    This paper is the second in a series devoted to the study of periodic super-spin chains. In our first paper (Gainutdinov et al., 2013 [3]), we have studied the symmetry algebra of the periodic gℓ(1|1) spin chain. In technical terms, this spin chain is built out of the alternating product of the gℓ(1|1) fundamental representation and its dual. The local energy densities — the nearest neighbour Heisenberg-like couplings — provide a representation of the Jones–Temperley–Lieb (JTL) algebra JTL N . The symmetry algebra is then the centralizer of JTL N , and turns out to be smaller than for the open chain, since it is now only a subalgebra of U q sℓ(2) at q=i — dubbed U q odd sℓ(2) in Gainutdinov et al. (2013) [3]. A crucial step in our associative algebraic approach to bulk logarithmic conformal field theory (LCFT) is then the analysis of the spin chain as a bimodule over U q odd sℓ(2) and JTL N . While our ultimate goal is to use this bimodule to deduce properties of the LCFT in the continuum limit, its derivation is sufficiently involved to be the sole subject of this paper. We describe representation theory of the centralizer and then use it to find a decomposition of the periodic gℓ(1|1) spin chain over JTL N for any even N and ultimately a corresponding bimodule structure. Applications of our results to the analysis of the bulk LCFT will then be discussed in the third part of this series

  19. Weakly spin-dependent band structures of antiferromagnetic perovskite LaMO3(M  =  Cr, Mn, Fe).

    Science.gov (United States)

    Okugawa, Takuya; Ohno, Kaoru; Noda, Yusuke; Nakamura, Shinichiro

    2018-02-21

    We investigate the spin-dependent electronic states of antiferromagnetic (AFM) lanthanum chromite (LaCrO 3 ), lanthanum manganite (LaMnO 3 ), and lanthanum ferrite (LaFeO 3 ) using spin-polarized first-principles density functional theory with Hubbard U correction. The band structures are calculated for 15 types of their different AFM structures. It is verified for these structures that there is a very simple rule to identify which wave number [Formula: see text] exhibits spin splitting or degeneracy in the band structure. This rule uses the symmetry operations that map the up-spin atoms onto the down-spin atoms. The resulting spin splitting is very small for the most stable spin configuration of the most stable experimental structure. We discuss a plausible benefit of this characteristic, i.e. the direction-independence of the spin current, in electrode applications.

  20. High spin structure of nuclei near N = 50 shell gap and search for high-spin isomers using time stamped data

    International Nuclear Information System (INIS)

    Saha, S.; Palit, R.; Trivedi, T.; Sethi, J.; Joshi, P.K.; Naidu, B.S.; Donthi, R.; Jadhav, S.; Nanal, V.; Pillay, R.G.; Jain, H.C.; Kumar, S.; Biswas, D.C.; Mukherjee, G.; Saha, S.

    2011-01-01

    Information on the high-spin states of nuclei promises to provide stringent test of the interaction of the Hamiltonian used in the calculation due to smaller basis space for high J-values. It is reported in a recent shell model review that no interaction is optimized for the region of interest around N = 50 and Z = 40 shell closure. The detailed spectroscopic information of the medium and high spin states in these nuclei is required to understand the shape transition between spherical and deformed shapes at N =60 as the higher orbitals are filled. Structure of isomers near shell closure carries important information of, for example, the extent of core excitation. In the present work, the spectroscopic study of the high spin states of 89 Zr isotope have been discussed

  1. Magnetic structure and spin dynamics of the quasi-one-dimensional spin-chain antiferromagnet BaCo2V2O8

    DEFF Research Database (Denmark)

    Kawasaki, Yu; Gavilano, Jorge L.; Keller, Lukas

    2011-01-01

    We report a neutron diffraction and muon spin relaxation mu SR study of static and dynamical magnetic properties of BaCo2V2O8, a quasi-one-dimensional spin-chain system. A proposed model for the antiferromagnetic structure includes: a propagation vector (k) over right arrow (AF) = (0......,0,1), independent of external magnetic fields for fields below a critical value H-c(T). The ordered moments of 2.18 mu(B) per Co ion are aligned along the crystallographic c axis. Within the screw chains, along the c axis, the moments are arranged antiferromagnetically. In the basal planes the spins are arranged...... ferromagnetically (forming zigzag paths) along one of the axes and antiferromagnetically along the other. The temperature dependence of the sublattice magnetization is consistent with the expectations of the three-dimensional (3D) Ising model. A similar behavior is observed for the internal static fields...

  2. Corrections to nucleon spin structure asymmetries measured on nuclear polarized targets

    International Nuclear Information System (INIS)

    Rondon, O.A.

    1999-01-01

    The nucleon spin structure functions have been extracted from measurements of asymmetries in deep inelastic scattering of polarized leptons on polarized nuclei. The polarized nuclei present in practical targets: H, 2 H, 3 He, 14 N, 15 N, 6 Li, and 7 Li, are, with the exception of hydrogen, systems of bound nucleons, some of which can attain significant degrees of alignment. All the aligned nucleons contribute to the asymmetries. The contributions of each nuclear species to the asymmetry have to be carefully determined, before a reliable value for the net nucleon asymmetry is obtained. For this purpose, the spin component of the nuclear angular momentum for every nuclear state and the probability of each state have to be known with sufficient accuracy. In this paper I discuss the basic corrections used to estimate the contributions of the different nuclei, with emphasis on the A=6 and 7 Li isotopes present in the Li 2 H polarized target used during SLAC Experiment 155 to study the deuteron spin structure. copyright 1999 The American Physical Society

  3. Study of the nucleon spin structure functions: the E154 experiment at SLAC

    International Nuclear Information System (INIS)

    Sabatie, Franck

    1998-01-01

    In experiment E154 at SLAC, the spin dependent structure function g 1 n was measured by scattering longitudinally polarized 50 GeV electrons off a longitudinally polarized helium 3 target. We report the integral over the measured x range to be ∫ 0.014 0.7 g 1 n (x,5 GeV 2 )dx = -0.0348 ± 0.0033 ± 0.0043 ± 0.0014. We observe relatively large values of g 1 n at low x, calling into question the reliability of the data extrapolation down to x equal 0. Such a divergent behavior seems to disagree with the prediction of the Regge theory but can be quantitatively explained by perturbative QCD. Moreover, we have performed a NLO perturbative QCD analysis of the world data on g 1 , paying careful attention to both the theoretical hypothesis and the calculation of errors. Using a parametrization of the polarized parton distribution at a low scale, we can access the fraction of spin carried by quarks: ΔΣ = 29 ± 6 pc in the MS-bar scheme, and ΔΣ = 37 ± 7 pc in the AB scheme. The gluon contribution to the nucleon spin is not well enough constrained by the current data, but seems to lie between 0 and 2. This study allows us to extract the first moment of the g 1 structure function and we find agreement with the Bjorken sum rule expectations. (author) [fr

  4. Noncollinear Spin Structure in Fe--Ni Invar Alloy Probed by Magnetic EXAFS at High Pressure

    Science.gov (United States)

    Matsumoto, Ken; Maruyama, Hiroshi; Ishimatsu, Naoki; Kawamura, Naomi; Mizumaki, Masaichiro; Irifune, Tetsuo; Sumiya, Hitoshi

    2011-02-01

    To examine theoretical models of the Invar effect, X-ray magnetic circular dichroism and magnetic extended X-ray absorption fine structure (MEXAFS) measurements are performed under high pressures at the Fe and Ni K-edges in 35.4 at. % Ni--Fe alloy. An oscillatory MEXAFS signal is observed up to 6 GPa. Its amplitude significantly decreases with increasing pressure. The magnetic component of the radial distribution function, obtained by taking the Fourier transform, shows a different reduction in the ferromagnetic correlations of Fe and Ni absorbing atoms. The present results are favorable to the noncollinear spin structure picture rather than the Fe 2γ-state model.

  5. Electric-field tunable spin diode FMR in patterned PMN-PT/NiFe structures

    Energy Technology Data Exchange (ETDEWEB)

    Ziętek, Slawomir, E-mail: zietek@agh.edu.pl; Skowroński, Witold; Stobiecki, Tomasz [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Ogrodnik, Piotr, E-mail: piotrogr@if.pw.edu.pl [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warszawa (Poland); Stobiecki, Feliks [Institute of Molecular Physics, Polish Academy of Sciences, ul. Smoluchowskiego 17, 60-179 Poznań (Poland); Dijken, Sebastiaan van [NanoSpin, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto (Finland); Barnaś, Józef [Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań (Poland); Institute of Molecular Physics, Polish Academy of Sciences, ul. Smoluchowskiego 17, 60-179 Poznań (Poland)

    2016-08-15

    Dynamic properties of NiFe thin films on PMN-PT piezoelectric substrate are investigated using the spin-diode method. Ferromagnetic resonance (FMR) spectra of microstrips with varying width are measured as a function of magnetic field and frequency. The FMR frequency is shown to depend on the electric field applied across the substrate, which induces strain in the NiFe layer. Electric field tunability of up to 100 MHz per 1 kV/cm is achieved. An analytical model based on total energy minimization and the Landau-Lifshitz-Gilbert equation, taking into account the magnetostriction effect, is used to explain the measured dynamics. Based on this model, conditions for optimal electric-field tunable spin diode FMR in patterned NiFe/PMN-PT structures are derived.

  6. The Deuteron Spin-dependent Structure Function $g^{d}_1$ and its First Moment

    CERN Document Server

    Alexakhin, V.Yu.; Alexeev, G.D.; Alexeev, M.; Amoroso, A.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Becker, M.; Bedfer, Y.; Bernet, C.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.P.; Bytchkov, V.N.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.A.; Costa, S.; Crespo, M.L.; d'Hose, N.; Dalla Torre, S.; Das, S.; Dasgupta, S.S.; De Masi, R.; Dedek, N.; Demchenko, D.; Denisov, O.Yu.; Dhara, L.; Diaz, V.; Dinkelbach, A.M.; Donskov, S.V.; Dorofeev, V.A.; Doshita, N.; Duic, V.; Dunnweber, W.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; M. Finger jr.; Fischer, H.; Franz, J.; Friedrich, J.M.; Frolov, V.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.M.; Grajek, O.A.; Grasso, A.; Grube, B.; Guskov, A.; Haas, F.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.H.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Horn, I.; Ilgner, C.; Ioukaev, A.I.; Ivanchin, I.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N.I.; Kabuss, E.; Kang, D.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Komissarov, E.V.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Korentchenko, A.S.; Korzenev, A.; Kotzinian, A.M.; Koutchinski, N.A.; Kouznetsov, O.; Kowalik, K.; Kramer, D.; Kravchuk, N.P.; Krivokhizhin, G.V.; Kroumchtein, Z.V.; Kubart, J.; Kuhn, R.; Kukhtin, V.; Kunne, F.; Kurek, K.; Ladygin, M.E.; Lamanna, M.; Le Goff, J.M.; Leberig, M.; Lednev, A.A.; Lehmann, A.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Masek, L.; Massmann, F.; Matsuda, T.; Matthia, D.; Maximov, A.N.; Meyer, W.; Mielech, A.; Mikhailov, Yu. V.; Moinester, M.A.; Nagel, T.; Nahle, O.; Nassalski, J.; Neliba, S.; Neyret, D.P.; Nikolaenko, V.I.; Nikolaev, K.; Nozdrin, A.A.; Obraztsov, V.F.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Peshekhonov, D.V.; Peshekhonov, V.D.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pontecorvo, G.; Popov, A.A.; Pretz, J.; Procureur, S.; Quintans, C.; Ramos, S.; Reicherz, G.; Rondio, E.; Rozhdestvensky, A.M.; Ryabchikov, D.; Samoylenko, V.D.; Sandacz, A.; Santos, H.; Sapozhnikov, M.G.; Savin, I.A.; Schiavon, P.; Schill, C.; Schmitt, L.; Schroeder, W.; Seeharsch, D.; Seimetz, M.; Setter, D.; Shevchenko, O.Yu.; Siebert, H.W.; Silva, L.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sozzi, F.; Srnka, A.; Stinzing, F.; Stolarski, M.; Sugonyaev, V.P.; Sulc, M.; Sulej, R.; Tchalishev, V.V.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Tkatchev, L.G.; Trippel, S.; Venugopal, G.; Virius, M.; Vlassov, N.V.; Webb, R.; Weise, E.; Weitzel, Q.; Windmolders, R.; Wislicki, W.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Zhao, J.; Zvyagin, A.

    2007-01-01

    We present a measurement of the deuteron spin-dependent structure function g^d_1 based on the data collected by the COMPASS experiment at CERN during the years 2002-2004. The data provide an accurate evaluation for \\Gamma^d_1, the first moment of g^d_1(x), and for the matrix element of the singlet axial current, a_0. The results of QCD fits in the next to leading order (NLO) on all g1 deep inelastic scattering data are also presented. They provide two solutions with the gluon spin distribution function \\Delta_G positive or negative, which describe the data equally well. In both cases, at Q^2 = 3(GeV/c)^2 the first moment of \\Delta G is found to be of the order of 0:2 - 0:3 in absolute value.

  7. Neutron diffraction and ultrasonic studies of spin-slip structures in holmium

    Energy Technology Data Exchange (ETDEWEB)

    Venter, Andrew M. [Atomic Energy Corporation of S A (Ltd), P O Box 582, Pretoria (South Africa); Du Plessis, Paul de V [Physics Department, University of the Witwatersrand, Private Bag 3, PO Wits 2050, Johannesburg (South Africa)

    1997-06-16

    Spin-slip behaviour in high-purity holmium single crystals is characterized by neutron diffraction and ultrasonic velocity and attenuation measurements as a function of temperature and of magnetic field applied along b, c, and a axes. Neutron diffraction measurements of intensity and turn angle give information on wave vector lock-in effects for various spin-slip structures in applied fields. These findings are supplemented with ultrasonic studies of the elastic constants C{sub 33} and C{sub 44} and corresponding attenuation coefficients {alpha}{sub 33} and {alpha}{sub 44}. Various phase diagrams are presented and results compared with experiments by other groups and with some theoretical predictions. (author)

  8. Structure of high-spin states in A {approx} 60 region

    Energy Technology Data Exchange (ETDEWEB)

    Nakada, Hitoshi [Chiba Univ. (Japan); Furutaka, K.; Hatsukawa, Y. [and others

    1998-03-01

    High-spin states in the proton-rich Cu-Zn nuclei are investigated by the experiments at JAERI. New levels and {gamma}-rays are identified by the particle-{gamma}-{gamma} coincidence, and J{sup P} assignments are made via the DCO ratio analysis. Yrast sequences are observed up to J {approx} 18 for {sup 62}Zn, and {sup 64}Zn, J {approx} 27/2 for {sup 61}Cu and J {approx} 23/2 for {sup 63}Cu. Though we cannot settle new J{sup P} values for {sup 61,63}Zn, their yrast sequence is also extended. In {sup 64}Zn, a doublet of {gamma}-rays is discovered at 1315 keV, clarifying the similarity in the level scheme between {sup 62}Zn and {sup 64}Zn. We reproduce the yrast levels by a shell-model calculation, by which structure of the high-spin states is further studied. A parity change in the yrast sequence is established, in which the unique-parity orbit 0g{sub 9/2} plays an essential role; one nucleon excitation to g{sub 9/2} gains high angular momentum with low seniority, at the cost of the single-parity energy. Second parity-change is also suggested by the calculation. Such parity change seems characteristic to spherical or nearly spherical nuclei. In {sup 61}Cu, concentration of the {gamma}-ray intensity is observed. This happens because a stretched 3-quasiparticle configuration including 0g{sub 9/2} is relatively stable, similarly to some isomers. Thus, by studying the structure of the high-spin states of the A {approx} 60 nuclei, we have clarified the role of unique-parity orbit in high-spin states, which may be generic to spherical and nearly spherical nuclei. (J.P.N.)

  9. Aharonov-Casher and spin Hall effects in mesoscopic ring structures with strong spin-orbit interaction

    Czech Academy of Sciences Publication Activity Database

    Borunda, M.F.; Liu, X.; Kovalev, A.A.; Liu, X.-J.; Jungwirth, Tomáš; Sinova, J.

    2008-01-01

    Roč. 78, č. 24 (2008), 245315/1-245315/9 ISSN 1098-0121 R&D Projects: GA MŠk LC510; GA AV ČR KAN400100652; GA ČR GEFON/06/E002 EU Projects: European Commission(XE) 015728 - NANOSPIN Institutional research plan: CEZ:AV0Z10100521 Keywords : Aharonov-Casher effect * spin Hall effect * spin-orbit interaction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.322, year: 2008

  10. Measurement of the Proton and Deuteron Spin Structure Functions G1 and G2

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, Al

    2003-04-02

    The SLAC experiment E155 was a deep-inelastic scattering experiment that scattered polarized electrons off polarized proton and deuteron targets in the effort to measure precisely the proton and deuteron spin structure functions. The nucleon structure functions g{sub 1} and g{sub 2} are important quantities that help test our present models of nucleon structure. Such information can help quantify the constituent contributions to the nucleon spin. The structure functions g{sub 1}{sup p} and G{sub 1}{sup d} have been measured over the kinematic range 0.01 {le} x {le} 0.9 and 1 {le} Q{sup 2} {le} 40 GeV{sup 2} by scattering 48.4 GeV longitudinally polarized electrons off longitudinally polarized protons and deuterons. In addition, the structure functions g{sub 2}{sup p} and g{sub 2}{sup d} have been measured over the kinematic range 0.01 {le} x {le} 0.7 and 1 {le} Q{sup 2} {le} 17 GeV{sup 2} by scattering 38.8 GeV longitudinally polarized electrons off transversely polarized protons and deuterons. The measurements of g{sub 1} confirm the Bjorken sum rule and find the net quark polarization to be {Delta}{Sigma} = 0.23 {+-} 0.04 {+-} 0.6 while g{sub 2} is found to be consistent with the g{sub 2}{sup WW} model.

  11. SUSY’s Ladder: reframing sequestering at Large Volume

    Energy Technology Data Exchange (ETDEWEB)

    Reece, Matthew [Department of Physics, Harvard University,Cambridge, MA 02138 (United States); Xue, Wei [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States)

    2016-04-07

    Theories with approximate no-scale structure, such as the Large Volume Scenario, have a distinctive hierarchy of multiple mass scales in between TeV gaugino masses and the Planck scale, which we call SUSY’s Ladder. This is a particular realization of Split Supersymmetry in which the same small parameter suppresses gaugino masses relative to scalar soft masses, scalar soft masses relative to the gravitino mass, and the UV cutoff or string scale relative to the Planck scale. This scenario has many phenomenologically interesting properties, and can avoid dangers including the gravitino problem, flavor problems, and the moduli-induced LSP problem that plague other supersymmetric theories. We study SUSY’s Ladder using a superspace formalism that makes the mysterious cancelations in previous computations manifest. This opens the possibility of a consistent effective field theory understanding of the phenomenology of these scenarios, based on power-counting in the small ratio of string to Planck scales. We also show that four-dimensional theories with approximate no-scale structure enforced by a single volume modulus arise only from two special higher-dimensional theories: five-dimensional supergravity and ten-dimensional type IIB supergravity. This gives a phenomenological argument in favor of ten dimensional ultraviolet physics which is different from standard arguments based on the consistency of superstring theory.

  12. Measurement of the spin-dependent structure-functions of the proton and the deuteron

    CERN Multimedia

    2002-01-01

    % NA47 %title \\\\ \\\\The physics motivation of the experiments of the Spin Muon Collaboration is to better understand how the nucleon spin is built-up by its partons and to test the fundamental Bjorken sum rule. \\\\ \\\\The spin-dependent structure functions $g _{1}(x)$ of the proton and the deuteron are determined from the measured cross section asymmetries for deep inelastic scattering of longitudinally polarized muons from longitudinally polarized nucleons. The experiment is similar to the NA2 one of the European Muon Collaboration in which the violation of the Ellis-Jaffe sum rule for the proton was found. \\\\ \\\\The apparatus is the upgraded forward spectrometer which was used originally by the European and New Muon Collaborations. To minimize the systematic uncertainties the target contains two oppositely polarized cells, which were exposed to the muon beam simultaneously. For the experiments in 1991 and 1992 the original EMC polarized target was reinstalled. In 1993 a new polarized target was put into operati...

  13. Thermoelectric Properties of Solution-Processed n-Doped Ladder-Type Conducting Polymers

    DEFF Research Database (Denmark)

    Wang, Suhao; Sun, Hengda; Ail, Ujwala

    2016-01-01

    Ladder-type "torsion-free" conducting polymers (e.g., polybenzimidazobenzophenanthroline (BBL)) can outperform "structurally distorted" donor-acceptor polymers (e.g., P(NDI2OD-T2)), in terms of conductivity and thermoelectric power factor. The polaron delocalization length is larger in BBL than...

  14. Commutation-relation-preserving ladder operators for propagating optical fields in nonuniform lossy media

    DEFF Research Database (Denmark)

    Partanen, Mikko; Häyrynen, Teppo; Tulkki, Jukka

    2015-01-01

    We have recently developed a quantized fluctuational electrodynamics (QFED) formalism to describe the quantum aspects of local thermal balance formation and to formulate the electromagnetic field ladder operators so that they no longer exhibit the anomalies reported for resonant structures. Here we...

  15. The climate learning ladder. A pragmatic procedure to support climate adaptation

    NARCIS (Netherlands)

    Werners, S.E.; Tabara, J.D.; Gensuo, J.; McEvoy, D.; Dai, X.Q.; Neufeldt, H.; West, J.; Serra, A.

    2010-01-01

    We introduce a new pragmatic procedure called the climate learning ladder to structure policy analysis, support reflection and identify critical decisions to support climate adaptation. This tool is the result of the reflexive learning process that occurred while developing innovative appraisal

  16. Relation between molecular electronic structure and nuclear spin-induced circular dichroism

    DEFF Research Database (Denmark)

    Štěpánek, Petr; Coriani, Sonia; Sundholm, Dage

    2017-01-01

    with the spatial distribution of the excited states and couplings between them, reflecting changes in molecular structure and conformation. This constitutes a marked difference to the nuclear magnetic resonance (NMR) chemical shift, which only reflects the local molecular structure in the ground electronic state......The recently theoretically described nuclear spin-induced circular dichroism (NSCD) is a promising method for the optical detection of nuclear magnetization. NSCD involves both optical excitations of the molecule and hyperfine interactions and, thus, it offers a means to realize a spectroscopy...... with spatially localized, high-resolution information. To survey the factors relating the molecular and electronic structure to the NSCD signal, we theoretically investigate NSCD of twenty structures of the four most common nucleic acid bases (adenine, guanine, thymine, cytosine). The NSCD signal correlates...

  17. [Application of electrostatic spinning technology in nano-structured polymer scaffold].

    Science.gov (United States)

    Chen, Denglong; Li, Min; Fang, Qian

    2007-04-01

    To review the latest development in the research on the application of the electrostatic spinning technology in preparation of the nanometer high polymer scaffold. The related articles published at home and abroad during the recent years were extensively reviewed and comprehensively analyzed. Micro/nano-structure and space topology on the surfaces of the scaffold materials, especially the weaving structure, were considered to have an important effect on the cell adhesion, proliferation, directional growth, and biological activation. The electrospun scaffold was reported to have a resemblance to the structure of the extracellular matrix and could be used as a promising scaffold for the tissue engineering application. The electrospun scaffolds were applied to the cartilage, bone, blood vessel, heart, and nerve tissue engineering fields. The nano-structured polymer scaffold can support the cell adhesion, proliferation, location, and differentiation, and this kind of scaffold has a considerable value in the tissue engineering field.

  18. Structure and properties of quarternary and tetragonal Heusler compounds for spintronics and spin transver torque applications

    Energy Technology Data Exchange (ETDEWEB)

    Zamani, Vajiheh Alijani

    2012-03-07

    This work is divided into two parts: part 1 is focused on the prediction of half-metallicity in quaternary Heusler compounds and their potential for spintronic applications and part 2 on the structural properties of Mn{sub 2}-based Heusler alloys and tuning the magnetism of them from soft to hard-magnetic for spin-transfer torque applications. In part 1, three different series of quaternary Heusler compounds are investigated, XX'MnGa (X=Cu, Ni and X'=Fe,Co), CoFeMnZ (Z=Al,Ga,Si,Ge), and Co{sub 2-x}Rh{sub x}MnZ (Z=Ga,Sn,Sb). All of these quaternary compounds except CuCoMnGa are predicted to be half-metallic ferromagnets by ab-initio electronic structure calculations. In the XX'MnGa class of compounds, NiFeMnGa has a low Curie temperature for technological applications but NiCoMnGa with a high spin polarization, magnetic moment, and Curie temperature is an interesting new material for spintronics applications. All CoFeMnZ compounds exhibit a cubic Heusler structur and their magnetic moments are in fair agreement with the Slater-Pauling rule indicating the halfmetallicity and high spin polarization required for spintronics applications. Their high Curie temperatures make them suitable for utilization at room temperature and above. The structural investigation revealed that the crystal structure of all Co{sub 2-x}Rh{sub x}MnZ compounds aside from CoRhMnSn exhibit different types of anti-site disorder. The magnetic moments of the disordered compounds deviate from the Slater-Pauling rule indicating that 100% spin polarization are not realized in CoRhMnGa, CoRhMnSb, and Co{sub 0.5}Rh{sub 1.5}MnSb. Exchange of one Co in Co{sub 2}MnSn by Rh results in the stable, well-ordered compound CoRhMnSn. This exchange of one of the magnetic Co atoms by a non-magnetic Rh atom keeps the magnetic properties and half-metallicity intact. In part 2, two series of Mn{sub 2}-based Heusler alloys are investigated, Mn{sub 3-x}Co{sub x}Ga and Mn{sub 2-x}Rh{sub 1+x}Sn. It has been

  19. Clinical ladder program implementation: a project guide.

    Science.gov (United States)

    Ko, Yu Kyung; Yu, Soyoung

    2014-11-01

    This article describes the development of a clinical ladder program (CLP) implementation linked to a promotion system for nurses. The CLP task force developed criteria for each level of performance and a performance evaluation tool reflecting the self-motivation of the applicant for professional development. One year after implementation, the number of nurses taking graduate courses increased, and 7 nurses were promoted to nurse manager positions.

  20. Level crossing, spin structure factor and quantum phases of the frustrated spin-1/2 chain with first and second neighbor exchange.

    Science.gov (United States)

    Kumar, Manoranjan; Parvej, Aslam; Soos, Zoltán G

    2015-08-12

    The spin-1/2 chain with isotropic Heisenberg exchange J1, J2  >  0 between first and second neighbors is frustrated for either sign of J1. Its quantum phase diagram has critical points at fixed J1/J2 between gapless phases with nondegenerate ground state (GS) and quasi-long-range order (QLRO) and gapped phases with doubly degenerate GS and spin correlation functions of finite range. In finite chains, exact diagonalization (ED) estimates critical points as level crossing of excited states. GS spin correlations enter in the spin structure factor S(q) that diverges at wave vector qm in QLRO(q(m)) phases with periodicity 2π/q(m) but remains finite in gapped phases. S(q(m)) is evaluated using ED and density matrix renormalization group (DMRG) calculations. Level crossing and the magnitude of S(q(m)) are independent and complementary probes of quantum phases, based respectively on excited and ground states. Both indicate a gapless QLRO(π/2) phase between  -1.2  quantum critical points at small frustration J2 but disagree in the sector of weak exchange J1 between Heisenberg antiferromagnetic chains on sublattices of odd and even-numbered sites.

  1. The deuteron spin-dependent structure function and its first moment

    Czech Academy of Sciences Publication Activity Database

    Alexakhin, V. Yu.; Alexandrov, Yu.; Alexeev, G. D.; Alexeev, M.; Amoroso, A.; Badelek, B.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Becker, M.; Bedfer, Y.; Bernet, C.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.P.; Bytchkov, V.N.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.A.; Costa, S.; Crespo, M.L.; d'Hose, N.; Dalla Torre, S.; Das, S.; Dasgupta, S. S.; De Masi, R.; Dedek, N.; Demchenko, D.; Denisov, O.Yu.; Dhara, L.; Diaz, V.; Dinkelbach, A. M.; Donskov, S.V.; Dorofeev, V. A.; Doshita, N.; Duic, V.; Dunnweber, W.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger jr., M.; Fischer, H.; Franz, J.; Friedrich, J.M.; Frolov, V.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.M.; Grajek, O.A.; Grasso, A.; Grube, B.; Guskov, A.; Haas, F.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.H.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Horn, I.; Ilgner, C.; Ioukaev, A.I.; Ivanchin, I.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N. I.; Kabuss, E.; Kang, D.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Komissarov, E.V.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Korentchenko, A.S.; Korzenev, A.; Kotzinian, A.M.; Koutchinski, N.A.; Kouznetsov, O.; Kowalik, K.; Kramer, D.; Kravchuk, N.P.; Krivokhizhin, G.V.; Kroumchtein, Z.V.; Kubart, J.; Kuhn, R.; Kukhtin, V.; Kunne, F.; Kurek, K.; Ladygin, M.E.; Lamanna, M.; Le Goff, J.M.; Leberig, M.; Lednev, A.A.; Lehmann, A.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Masek, L.; Massmann, F.; Matsuda, T.; Matthia, D.; Maximov, A.N.; Meyer, W.; Mielech, A.; Mikhailov, Yu.V.; Moinester, M.A.; Nagel, T.; Nahle, O.; Nassalski, J.; Neliba, S.; Neyret, D.P.; Nikolaenko, V.I.; Nikolaev, K.; Nozdrin, A.A.; Obraztsov, V. F.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Peshekhonov, D.V.; Peshekhonov, V.D.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pontecorvo, G.; Popov, A.A.; Pretz, J.; Procureur, S.; Quintans, C.; Ramos, S.; Reicherz, G.; Rondio, E.; Rozhdestvensky, A.M.; Ryabchikov, D.; Samoylenko, V.D.; Sandacz, A.; Santos, H.; Sapozhnikov, M.G.; Savin, I.A.; Schiavon, P.; Schill, C.; Schmitt, L.; Schroeder, W.; Seeharsch, D.; Seimetz, M.; Setter, D.; Shevchenko, O.Yu.; Siebert, H.-W.; Silva, L.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sozzi, F.; Srnka, Aleš; Stinzing, F.; Stolarski, M.; Sugonyaev, V.P.; Sulc, M.; Sulej, R.; Tchalishev, V.V.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Tkatchev, L.G.; Trippel, S.; Venugopal, G.; Virius, M.; Vlassov, N.V.; Webb, R.; Weise, E.; Weitzel, Q.; Windmolders, R.; Wislicki, W.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Zhao, J.; Ziegler, R.; Zvyagin, A.

    2007-01-01

    Roč. 647, č. 1 (2007), s. 8-17 ISSN 0370-2693 R&D Projects: GA MŠk ME 492 Institutional research plan: CEZ:AV0Z20650511 Keywords : Deep inelastic scattering * Spin * Structure function * QCD analysis * A1 * g1 Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.189, year: 2007 http://www.sciencedirect.com/science/article/B6TVN-4MYVG5P-1/2/387d70e7f30fb736514de259c62118d9

  2. Temperature and Pressure Sensors Based on Spin-Allowed Broadband Luminescence of Doped Orthorhombic Perovskite Structures

    Science.gov (United States)

    Eldridge, Jeffrey I. (Inventor); Chambers, Matthew D. (Inventor)

    2014-01-01

    Systems and methods that are capable of measuring pressure or temperature based on luminescence are discussed herein. These systems and methods are based on spin-allowed broadband luminescence of sensors with orthorhombic perovskite structures of rare earth aluminates doped with chromium or similar transition metals, such as chromium-doped gadolinium aluminate. Luminescence from these sensors can be measured to determine at least one of temperature or pressure, based on either the intense luminescence of these sensors, even at high temperatures, or low temperature techniques discussed herein.

  3. Comment on ‘Adjacent spin operator dynamical structure factor of the S = 1/2 Heisenberg chain’

    International Nuclear Information System (INIS)

    De Gier, Jan

    2012-01-01

    We consider the paper ‘Adjacent spin operator dynamical structure factor of the S = 1/2 Heisenberg chain’, by Klauser, Mossel and Caux (2012 J. Stat. Mech. P03012) to be a new and important step in the numerical analysis of the correlation functions of quantum spin chains. The correlation functions considered in this paper were not previously computed, their analytical study is extremely complicated and the numerical results can be used for comparison with experiments. (news and perspectives)

  4. Effects of aluminum trichloride and magnesium chloride on the synthesis of ladder polyphenylsilsesquioxane

    Directory of Open Access Journals (Sweden)

    Jiang Yunyun

    2012-01-01

    Full Text Available Ladder polyphenylsilsesquioxane (Ph-LPSQ has been synthesized at 80°C through the hydrolysis and condensation of phenyltrichlorosilane (PhSiCl3, with aluminum chloride (AlCl3 or magnesium chloride (MgCl2 as an assistant reactant. The Ph-LPSQ obtained has been characterized and analyzed by SEM, FTIR, TGA, 29Si NMR, and MALDI-TOF MS, and the effects of AlCl3and MgCl2on the structure regularity of Ph-LPSQ and the condensation polymerizationhavealso been studied. The results showed that Ph-LPSQ could be obtained in theAlCl3and MgCl2systems, respectively, but the experimental phenomena and results showed significant differences between the two systems. SEM observation revealed spherical Ph-LPSQ particles from the PhSiCl3/AlCl3system, but irregular and agglomerated Ph-LPSQ particles from the PhSiCl3/1.5(MgCl2 system. TGA, 29SiNMR, and MALDI-TOF MS indicated that the ladder structure of Ph-LPSQ from the PhSiCl3/1.5(MgCl2 system was more regular. Inthe PhSiCl3/AlCl3system, Al could be incorporated into the ladder chain structure through competing reactions between Si-O-Al and Si-O-Si, which slightly decreased the regularity of the ladder chain structure of Ph-LPSQ. Mechanistic analysis suggests that the presence of AlCl3or MgCl2in the hydrolysis and condensation system favors the intermolecular condensation of intermediate products of polyhydroxyl silanol to form a regular ladder structure.

  5. Deep inelastic scattering structure functions of holographic spin-1 hadrons with N f ≥ 1

    Science.gov (United States)

    Koile, Ezequiel; Macaluso, Sebastian; Schvellinger, Martin

    2014-01-01

    Two-point current correlation functions of the large N limit of supersymmetric and non-supersymmetric Yang-Mills theories at strong coupling are investigated in terms of their string theory dual models with quenched flavors. We consider non-Abelian global symmetry currents, which allow one to investigate vector mesons with N f > 1. From the correlation functions we construct the deep inelastic scattering hadronic tensor of spin-one mesons, obtaining the corresponding eight structure functions for polarized vector mesons. We obtain several relations among the structure functions. Relations among some of theirmoments are also derived. Aspects of the sub-leading contributions in the 1 /N and N f /N expansions are discussed. At leading order we find a universal behavior of the hadronic structure functions.

  6. Intrinsic properties of high-spin band structures in triaxial nuclei

    Science.gov (United States)

    Jehangir, S.; Bhat, G. H.; Sheikh, J. A.; Palit, R.; Ganai, P. A.

    2017-12-01

    The band structures of 68,70Ge, 128,130,132,134Ce and 132,134,136,138Nd are investigated using the triaxial projected shell model (TPSM) approach. These nuclei depict forking of the ground-state band into several s-bands and in some cases, both the lowest two observed s-bands depict neutron or proton character. It was discussed in our earlier work that this anomalous behaviour can be explained by considering γ-bands based on two-quasiparticle configurations. As the parent band and the γ-band built on it have the same intrinsic structure, g-factors of the two bands are expected to be similar. In the present work, we have undertaken a detailed investigation of g-factors for the excited band structures of the studied nuclei and the available data for a few high-spin states are shown to be in fair agreement with the predicted values.

  7. Laser - Polarized HE-3 Target Used for a Precision Measurement of the Neutron Spin Structure

    Energy Technology Data Exchange (ETDEWEB)

    Romalis, M

    2003-11-05

    This thesis describes a precision measurement of the deep inelastic neutron spin structure function g{sub 1}{sup n}(x). The main motivation for the experiment is a test of the Bjorken sum rule. Because of smaller statistical errors and broader kinematic coverage than in previous experiments, we are able to study in detail the behavior of the spin structure function g{sub 1}{sup n}(x) for low values of the Bjorken scaling variable x. We find that it has a strongly divergent behavior, in contradiction to the naive predictions of the Regge theory. This calls into question the methods commonly used for extrapolation of g{sub 1}{sup n}(x) to x = 0. The difference between the proton and the neutron spin structure functions is less divergent at low x, so a test of the Bjorken sum rule is possible. We confirm the sum rule with an accuracy of 8%. The experiment was performed at SLAC using a 50 GeV polarized electron beam and a polarized {sup 3}He target. In this thesis the polarized target is described in detail. We used the technique of Rb optical pumping and Rb-He spin exchange to polarize the {sup 3}He. Because of a novel mechanical design our target had the smallest dilution ever achieved for a high density gas target. Since this is a precision measurement, particular efforts were made to reduce the systematic errors due to the uncertainty in the target parameters. Most important parameters were measured by more than one method. We implemented novel techniques for measuring the thickness of the glass windows of the target, the {sup 3}He density, and the polarization. In particular, one of the methods for measuring the gas density relied on the broadening of the Rb optical absorption lines by collisions with {sup 3}He atoms. The calibration of this technique resulted in the most precise measurements of the pressure broadening parameters for {sup 3}He as well as several other gases, which are described in an Appendix. The polarization of the {sup 3}He was also measured by

  8. A Precision Measurement of the Neutron Spin Structure Functions Using a Polarized HE-3 Target

    Energy Technology Data Exchange (ETDEWEB)

    Smith, T

    2003-11-05

    This thesis describes a precision measurement of the neutron spin dependent structure function, g{sub 1}{sup n}(x). The measurement was made by the E154 collaboration at SLAC using a longitudinally polarized, 48.3 GeV electron beam, and a {sup 3}He target polarized by spin exchange with optically pumped rubidium. A target polarization as high as 50% was achieved. The elements of the experiment which pertain to the polarized {sup 3}He target will be described in detail in this thesis. To achieve a precision measurement, it has been necessary to minimize the systematic error from the uncertainty in the target parameters. All of the parameters of the target have been carefully measured, and the most important parameters of the target have been measured using multiple techniques. The polarization of the target was measured using nuclear magnetic resonance techniques, and has been calibrated using both proton NMR and by measuring the shift of the Rb Zeeman resonance frequency due to the {sup 3}He polarization. The fraction of events which originated in the {sup 3}He, as measured by the spectrometers, has been determined using a physical model of the target and the spectrometers. It was also measured during the experiment using a variable pressure {sup 3}He reference cell in place of the polarized {sup 3}He target. The spin dependent structure function g{sub 1}{sup n}(z) was measured in the Bjorken x range of 0.014 < x < 0.7 with an average Q{sup 2} of 5 (GeV/c){sup 2}. One of the primary motivations for this experiment was to test the Bjorken sum rule. Because the experiment had smaller statistical errors and a broader kinematic coverage than previous experiments, the behavior of the spin structure function g{sub 1}{sup n}(x) could be studied in detail at low values of the Bjorken scaling variable x. It was found that g{sub 1}{sup n}(x) has a strongly divergent behavior at low values of x, calling into question the methods commonly used to extrapolate the value of g

  9. Spin structure of exchange biased heterostructures. Fe/MnF{sub 2} and Fe/FeF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, B.

    2006-12-18

    In this work, the {sup 57}Fe probe layer technique is used in order to investigate the depth- and temperature-dependent Fe-layer spin structure of exchange biased Fe/MnF{sub 2} and Fe/FeF{sub 2} (pseudo-twinned) antiferromagnetic (AFM) systems by conversion electron Moessbauer spectroscopy (CEMS) and nuclear resonant scattering (NRS) of synchrotron radiation. Two kinds of samples with a 10 A {sup 57}Fe probe layer directly at or 35 A away from the interface, labeled as interface and center sample, respectively, were studied in this work. The results obtained by CEMS for Fe/MnF{sub 2} suggests that, at 80 K, i.e., above T{sub N}=67 K of MnF{sub 2}, the remanent state Fe-layer spin structure of the two studied samples are slightly different due to their different microstructure. In the temperature range from 300 K to 80 K, the Fe-layer spin structure does not change just by zero-field cooling the sample in remanence. For Fe/FeF{sub 2}, a continuous non-monotonic change of the remanent-state Fe spin structure was observed by cooling from 300 K to 18 K. NRS of synchrotron radiation was used to investigate the temperature- and depth-dependent Fe-layer spin structure during magnetization reversal in pseudo-twinned Fe/MnF{sub 2}. A depthdependent Fe spin structure in an applied magnetic field (applied along the bisector of the twin domains) was observed at 10 K, where the Fe spins closer to the interface are not aligned along the field direction. The depth-dependence disappears at 150 K. (orig.)

  10. Structure and spin density of ferric low-spin heme complexes determined with high-resolution ESEEM experiments at 35 GHz.

    Science.gov (United States)

    García-Rubio, Inés; Mitrikas, George

    2010-08-01

    The wide use of the heme group by nature is a consequence of its unusual "electronic flexibility." Major changes in the electronic structure of this molecule can result from small perturbations in its environment. To understand the way the electronic distribution is dictated by the structure of the heme site, it is extremely important to have methods to reliably determine both of them. In this work we propose a way to obtain this information in ferric low-spin heme centers via the determination of g, A, and Q tensors of the coordinated nitrogens using electron spin echo envelope modulation experiments at Q-band microwave frequencies. The results for two bisimidazole heme model complexes, namely, PPIX(Im)(2) and CPIII(Im)(2), where PPIX is protoporphyrin IX, CPIII is coproporphyrin III, and Im is imidazole, selectively labeled with (15)N on the heme or imidazole nitrogens are presented. The planes of the axial ligands were found to be parallel and oriented approximately along one of the N-Fe-N directions of the slightly ruffled porphyrin ring (approximately 10 degrees ). The spin density was determined to reside in an iron d orbital perpendicular to the heme plane and oriented along the other porphyrin N-Fe-N direction, perpendicular to the axial imidazoles. The benefit of the method presented here lies in the use of Q-band microwave frequencies, which improves the orientation selection, results in no/fewer combination lines in the spectra, and allows separation of the contributions of hyperfine and quadrupole interactions due to the fulfillment of the exact cancellation condition at g ( Z ) and the possibility of performing hyperfine decoupling experiments at the g ( X ) observer position. These experimental advantages make the interpretation of the spectra straightforward, which results in precise and reliable determination of the structure and spin distribution.

  11. The Precision Measurement of the Neutron Spin Structure Function Using Polarized HE-3 Target

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X

    2004-01-05

    Using a 48.6 GeV polarized electron beam scattering off a polarized {sup 3}He target at Stanford Linear Accelerator Centre (SLAC), they measured the neutron spin structure function g{sub 1}{sup n} over kinematic(x) ranging 0.014 < x <0.7 and 1 < Q{sup 2} < 17GeV{sup 2}. The measurement gave the integral result over the neutron spin structure function {integral}{sub 0.014}{sup 0.7} g{sub 1}{sup n}(x)dx = -0.036 {+-} 0.004(stat) {+-} 0.005(syst) at an average Q{sup 2} = 5GeV{sup 2}. Along with the proton results from SLAC E143 experiment (0.03 < x) and SMC experiment (0.014 < x < 0.03), they find the Bjorken sum rule appears to be largely saturated by the data integrated down to x of 0.014. However, they observe relatively large values for g{sub 1}{sup n} at low x. The result calls into question the usual methods (Regge theory) for extrapolating to x = 0 to find the full neutron integral {integral}{sub 0}{sup t} g{sub 1}{sup n}(x) dx, needed for testing the Quark-Parton Model (QMP).

  12. Magnetic transport property of NiFe/WSe2/NiFe spin valve structure

    International Nuclear Information System (INIS)

    Zhao, Kangkang; Xing, Yanhui; Han, Jun; Feng, Jiafeng; Shi, Wenhua; Zhang, Baoshun; Zeng, Zhongming

    2017-01-01

    Highlight: • Two-dimensional (2D) materials have been proposed as promising candidate for spintronic applications due to their atomic crystal structure and physical properties. • In this article, we introduce exfoliated few-layer tungsten diselenide (WSe 2 ) as spacer in a Py/WSe 2 /Py vertical spin valve. • In this junction, the WSe 2 spacer exhibits metallic behavior. • We observed negative magnetoresistance (MR) with a ratio of −1.1% at 4 K and −0.21% at 300 K. • A general phenomenological analysis of the negative MR property is discussed. • Our result is anticipated to be beneficial for future spintronic applications. - Abstract: Two-dimensional (2D) materials have been proposed as promising candidate for spintronic applications due to their atomic crystal structure and physical properties. Here, we introduce exfoliated few-layer tungsten diselenide (WSe 2 ) as spacer in a Py/WSe 2 /Py vertical spin valve. In this junction, the WSe 2 spacer exhibits metallic behavior. We observed negative magnetoresistance (MR) with a ratio of −1.1% at 4 K and −0.21% at 300 K. A general phenomenological analysis of the negative MR property is discussed. Our result is anticipated to be beneficial for future spintronic applications.

  13. Spin structure of the neutron ({sup 3}He) and the Bjoerken sum rule

    Energy Technology Data Exchange (ETDEWEB)

    Meziani, Z.E. [Stanford Univ., CA (United States)

    1994-12-01

    A first measurement of the longitudinal asymmetry of deep-inelastic scattering of polarized electrons from a polarized {sup 3}He target at energies ranging from 19 to 26 GeV has been performed at the Stanford Linear Accelerator Center (SLAC). The spin-structure function of the neutron g{sub 1}{sup n} has been extracted from the measured asymmetries. The Quark Parton Model (QPM) interpretation of the nucleon spin-structure function is examined in light of the new results. A test of the Ellis-Jaffe sum rule (E-J) on the neutron is performed at high momentum transfer and found to be satisfied. Furthermore, combining the proton results of the European Muon Collaboration (EMC) and the neutron results of E-142, the Bjoerken sum rule test is carried at high Q{sup 2} where higher order Perturbative Quantum Chromodynamics (PQCD) corrections and higher-twist corrections are smaller. The sum rule is saturated to within one standard deviation.

  14. Magnetic transport property of NiFe/WSe{sub 2}/NiFe spin valve structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Kangkang [Key Lab of Opto-electronics Technology, Ministry of Education, College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China); Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China); Xing, Yanhui, E-mail: xingyanhui@bjut.edu.cn [Key Lab of Opto-electronics Technology, Ministry of Education, College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China); Han, Jun [Key Lab of Opto-electronics Technology, Ministry of Education, College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China); Feng, Jiafeng [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing 100190 (China); Shi, Wenhua; Zhang, Baoshun [Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China); Zeng, Zhongming, E-mail: zmzeng2012@sinano.ac.cn [Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China)

    2017-06-15

    Highlight: • Two-dimensional (2D) materials have been proposed as promising candidate for spintronic applications due to their atomic crystal structure and physical properties. • In this article, we introduce exfoliated few-layer tungsten diselenide (WSe{sub 2}) as spacer in a Py/WSe{sub 2}/Py vertical spin valve. • In this junction, the WSe{sub 2} spacer exhibits metallic behavior. • We observed negative magnetoresistance (MR) with a ratio of −1.1% at 4 K and −0.21% at 300 K. • A general phenomenological analysis of the negative MR property is discussed. • Our result is anticipated to be beneficial for future spintronic applications. - Abstract: Two-dimensional (2D) materials have been proposed as promising candidate for spintronic applications due to their atomic crystal structure and physical properties. Here, we introduce exfoliated few-layer tungsten diselenide (WSe{sub 2}) as spacer in a Py/WSe{sub 2}/Py vertical spin valve. In this junction, the WSe{sub 2} spacer exhibits metallic behavior. We observed negative magnetoresistance (MR) with a ratio of −1.1% at 4 K and −0.21% at 300 K. A general phenomenological analysis of the negative MR property is discussed. Our result is anticipated to be beneficial for future spintronic applications.

  15. Longitudinal double spin asymmetry $A_1^p$ and spin-dependent structure function $g_1^p$ of the proton at low $x$ and low $Q^2$ from COMPASS

    CERN Document Server

    Nunes, A S

    2014-01-01

    The COMPASS experiment at CERN has collected a large sample of events of inelastic scattering of longitudinally polarised muons off longitudinally polarised protons in the non-perturbative region (four-momentum transfer squared $Q^2<1$~(GeV$^2$/$c^2$), with a Bjorken scaling variable in the range $4\\times 10^{-5}spin asymmetry $A_1^p$ and of the spin-dependent structure function $g_1^p$ of the proton in the region of low $x$ and low $Q^2$. The preliminary results of the analysis of these data yield non zero and positive asymmetries and of the structure function $g_1^p$. This is the first time that spin effects are observed at such low $x$.

  16. Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe4As4

    Science.gov (United States)

    Iida, Kazuki; Ishikado, Motoyuki; Nagai, Yuki; Yoshida, Hiroyuki; Christianson, Andrew D.; Murai, Naoki; Kawashima, Kenji; Yoshida, Yoshiyuki; Eisaki, Hiroshi; Iyo, Akira

    2017-09-01

    The dynamical spin susceptibility in the new-structure-type iron-based superconductor CaKFe4As4 was investigated by using a combination of inelastic neutron scattering (INS) measurements and random phase approximation (RPA) calculations. Powder INS measurements show that the spin resonance at Qres = 1.17(1) Å-1, corresponding to the (π ,π ) nesting wave vector in tetragonal notation, evolves below Tc. The characteristic energy of the spin resonance Eres = 12.5 meV is smaller than twice the size of the superconducting gap (2Δ). The broad energy feature of the dynamical susceptibility of the spin resonance can be explained by the RPA calculations, in which the different superconducting gaps on different Fermi surfaces are taken into account. Our INS and PRA studies demonstrate that the superconducting pairing nature in CaKFe4As4 is the s± symmetry.

  17. Enhancement of Lithium Niobate nanophotonic structures via spin-coating technique for optical waveguides application

    Directory of Open Access Journals (Sweden)

    Fakhri Makram A.

    2017-01-01

    Full Text Available This work is dedicated to investigation of temperature effects in Lithium Niobate (LiNbO3 nanostructures. The LiNbO3 nanostructures were deposited on glass substrate by spin-coating technique. LiNbO3 was set down at 3000 rpm for 30 sec and annealed from 100 to 600 °C. The structures were characterized and analyzed by scanning electron microscopy (SEM and ultra-violet visible (UV-vis spectrophotometer. The measured results have showed that by increasing annealing temperatures, the structures start to be more crystallized and be more homogenized until the optimum arrangement was achieved. Once this was accomplished, it's applicable for optical waveguides development. Eventually, it starts to be less crystallization and non-homogeneous. Energy gap was recorded to be at average value of 3.9 eV.

  18. Measurement of the Proton and Deuteron Spin Structure Function g1 in the Resonance Region

    International Nuclear Information System (INIS)

    Abe, K.; Akagi, T.; Perry Anthony; Antonov, R.; Arnold, R.G.; Todd Averett; Band, H.R.; Bauer, J.M.; Borel, H.; Peter Bosted; Vincent Breton; Button-Shafer, J.; Jian-Ping Chen; T.E. Chupp; J. Clendenin; C. Comptour; K.P. Coulter; G. Court; Donald Crabb; M. Daoudi; Donal Day; F.S. Dietrich; James Dunne; H. Dutz; R. Erbacher; J. Fellbaum; Andrew Feltham; Helene Fonvieille; Emil Frlez; D. Garvey; R. Gearhart; Javier Gomez; P. Grenier; Keith Griffioen; S. Hoeibraten; Emlyn Hughes; Charles Hyde-Wright; J.R. Johnson; D. Kawall; Andreas Klein; Sebastian Kuhn; M. Kuriki; Richard Lindgren; T.J. Liu; R.M. Lombard-Nelsen; Jacques Marroncle; Tomoyuki Maruyama; X.K. Maruyama; James Mccarthy; Werner Meyer; Zein-Eddine Meziani; Ralph Minehart; Joseph Mitchell; J. Morgenstern; Gerassimos Petratos; R. Pitthan; Dinko Pocanic; C. Prescott; R. Prepost; P. Raines; Brian Raue; D. Reyna; A. Rijllart; Yves Roblin; L. Rochester; Stephen Rock; Oscar Rondon-Aramayo; Ingo Sick; Lee Smith; Tim Smith; M. Spengos; F. Staley; P. Steiner; S. St. Lorant; L.M. Stuart; F. Suekane; Z.M. Szalata; Huabin Tang; Y. Terrien; Tracy Usher; Dieter Walz; Frank Wesselmann; J.L. White; K. Witte; C. Young; Brad Youngman; Haruo Yuta; G. Zapalac; Benedikt Zihlmann; Zimmermann, D.

    1997-01-01

    We have measured the proton and deuteron spin structure functions g 1 p and g 1 d in the region of the nucleon resonances for W 2 2 and Q 2 ≅ 0.5 and Q 2 ≅ 1.2 GeV 2 by inelastically scattering 9.7 GeV polarized electrons off polarized 15 NH 3 and 15 ND 3 targets. We observe significant structure in g 1 p in the resonance region. We have used the present results, together with the deep-inelastic data at higher W 2 , to extract Γ(Q 2 ) (triple b ond) ∫ 0 1 g 1 (x,Q 2 ) dx. This is the first information on the low-Q 2 evolution of Gamma toward the Gerasimov-Drell-Hearn limit at Q 2 = 0

  19. Density functional approximation for spin dependent quantum transport in magnetic nano structures

    International Nuclear Information System (INIS)

    Nyunt, Khine

    2009-01-01

    In quasi-classical theoretical framework, the transport of electrons and holes in semiconductor devices is treated with the Boltzmann transport equation or quantum-mechanical energy band theory - viz., the effective mass approximation and the random phase approximation. On the other hand, in the mesoscopic, nano electronic devices, for three- and lower- dimensional structures with nanometer scaling, the wave properties, spin, charge and the interactions between spin and charge of electrons are fully utilized, such as in artificial mini-Brillouin zones, quantum size effects, Coulomb blockade of single-electron tunneling and spin-polarized giant magnetoresistance tunneling. The complexity associated with the classical quantum-mechanical formalism in the study of transport in magnetic nano structures can be avoided by applying the so-called, Hohenberg-Kohns density functional theory. In particular, the N-electron problem is formulated as N one-electron equations where each electron interacts with all other electrons via an effective exchange-correlation potential. These interactions are augmented using the electron charge density. Plane wave sets and total energy pseudo-potential methods can be used self-consistently, to solve the Kohn-Sham one-electron equations. Because of the limitations of quasi-classical theory, it is more appropriate to treat the magneto-transport problem in nano structures by using quantum many-body theory. The starting point of the quantum transport theory is to take an external field as a perturbation for the many-particle system in equilibrium. This leads to a linear response and gives corresponding transport coefficients. One useful application of the Greens function techniques in quantum magneto-transport is to convert a homogeneous differential equation into an integral equation, viz., as in the time-dependent Schrodinger equation. We have applied to scattering of nano structural defects (impurities) in the electron gas (metal) as many

  20. Investigation of the field dependent spin structure of exchange coupled magnetic heterostructures

    International Nuclear Information System (INIS)

    Gurieva, Tatiana

    2016-05-01

    This thesis describes the investigation of the field dependent magnetic spin structure of an antiferromagnetically (AF) coupled Fe/Cr heterostructure sandwiched between a hardmagnetic FePt buffer layer and a softmagnetic Fe top layer. The depth-resolved experimental studies of this system were performed via Magneto-optical Kerr effect (MOKE), Vibrating Sample Magnetometry (VSM) and various measuring methods based on nuclear resonant scattering (NRS) technique. Nucleation and evolution of the magnetic spiral structure in the AF coupled Fe/Cr multilayer structure in an azimuthally rotating external magnetic field were observed using NRS. During the experiment a number of time-dependent magnetic side effects (magnetic after-effect, domain-wall creep effect) caused by the non-ideal structure of a real sample were observed and later explained. Creation of the magnetic spiral structure in rotating external magnetic field was simulated using a one-dimensional micromagnetic model.The cross-sectional magnetic X-ray diffraction technique was conceived and is theoretically described in the present work. This method allows to determine the magnetization state of an individual layer in the magnetic heterostructure. It is also applicable in studies of the magnetic structure of tiny samples where conventional x-ray reflectometry fails.

  1. A measurement of the proton’s spin structure function g2 at low Q2

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Pengjia [Univ. of Science and Technology of China, Hefei (China)

    2015-10-21

    JLab E08-027, a measurement of g2p and the longitudinal-transverse (LT) spin polarizability, successfully collected data from March to May, 2012. Nucleon spin structure study has been an active research area, which has attracted a very large effort from both experimentalists and theorists. The spin structure study for the last 2 decades has provided us with many exciting and often surprising results. Recently, new precision results in the low-to-intermediate momentum transfer Q2 region from JLab have provided extensive information on the nucleon structure in the confinement region and the transition region between asymptotic free to confinement. In particular, the extensive comparisons of experimental results with Chiral Perturbation Theory (the effective theory of QCD at low energy) calculations show general good agreements, but strong disagreement in the case of the neutron LT spin polarizability. This experiment completed the measurements of gp2 and the LT spin polarizability on the proton in the low-to-intermediate Q2 region. The experiment used a polarized proton (NH3) target for the first time in Hall A. Scattered electrons were detected by a pair of Hall A high resolution spectrometer (HRS) with a pair of septum magnets. To avoid too much depolarization of the target, beam current was limited to 50-100 nA during the experiment. Since the existing beam current monitors (BCMs), beam position monitors (BPMs) and calibration methods did not work at such a low current range, new BPM and BCM receivers were designed and used for current condition. A pair of super-harps and a tungsten calorimeter were installed to calibrate the BPMs and BCMs. To compensate for the effect of the 2.5/5T transverse magnet field, two chicane dipole magnets were installed. A pair of slow rasters were installed for the first time in Hall A, combining with a pair of fast raster. The standard Hall A DAQ system and the improved high resolution DAQ system were used to record the detector

  2. Spin electronics

    CERN Document Server

    Buhrman, Robert; Daughton, James; Molnár, Stephan; Roukes, Michael

    2004-01-01

    This report is a comparative review of spin electronics ("spintronics") research and development activities in the United States, Japan, and Western Europe conducted by a panel of leading U.S. experts in the field. It covers materials, fabrication and characterization of magnetic nanostructures, magnetism and spin control in magnetic nanostructures, magneto-optical properties of semiconductors, and magnetoelectronics and devices. The panel's conclusions are based on a literature review and a series of site visits to leading spin electronics research centers in Japan and Western Europe. The panel found that Japan is clearly the world leader in new material synthesis and characterization; it is also a leader in magneto-optical properties of semiconductor devices. Europe is strong in theory pertaining to spin electronics, including injection device structures such as tunneling devices, and band structure predictions of materials properties, and in development of magnetic semiconductors and semiconductor heterost...

  3. Electronic Structures of Magnetic Iron and Cobalt Thin Films on TUNGSTEN(001): a Spin-Polarized Inverse Photoemission Study

    Science.gov (United States)

    Cai, Qing

    Electronic structure is a central question in metallic magnetism as well as in magnetic materials research. The electronic properties in a two-dimensional system such as thin films of a few atomic layers is an important issue in surface science. The epitaxial thin film preparation and morphology are of special technological interests. In this thesis, these questions are addressed. Spin-polarized inverse photoemission spectroscopy is used to study the unoccupied electron band states in magnetic thin film magnets of Fe and Co epitaxially grown on W(001) surface. The clean W(001) surface was studied by angle -resolved inverse photoemission spectroscopy and the bulk band dispersion was determined. Ultrathin Fe overlayers on W(001) show a square lateral crystal structure similar to the bcc-Fe(001) surface. The electronic structure develops into a structure that is close to that of bulk Fe at about four atomic layers. In the normal-incidence spin polarized inverse photoemission spectra, direct transitions to the majority and minority final states near the H^'_ {25} point are identified in good agreement with the theoretical calculations. One Fe monolayer, or multilayers less than four, showed behavior corresponding to a gradually reduced Curie temperature. When the film thickness is reduced, the spin-resolved spectral behavior show that the majority spin signal peak moves from near the Fermi energy to about 1.3 eV while the minority peak stays at about the same position near 1.3 eV. The results are used to examine the spatial correlation of the spin fluctuations in the system in comparison with a theoretical spectral calculation, and favors the disordered-local-moment picture in the contemporary theory of itinerant magnetism. The Co overlayer shows an overlayer structure that consists of equivalent, mutually rotated domains of distorted hexagonal lateral structure. For one atomic layer of Co in that structure, which has a nominal lateral atomic density twice that of the

  4. Giant Spin Hall Effect and Switching Induced by Spin-Transfer Torque in a W /Co40Fe40B20/MgO Structure with Perpendicular Magnetic Anisotropy

    Science.gov (United States)

    Hao, Qiang; Xiao, Gang

    2015-03-01

    We obtain robust perpendicular magnetic anisotropy in a β -W /Co40Fe40B20/MgO structure without the need of any insertion layer between W and Co40Fe40B20 . This is achieved within a broad range of W thicknesses (3.0-9.0 nm), using a simple fabrication technique. We determine the spin Hall angle (0.40) and spin-diffusion length for the bulk β form of tungsten with a large spin-orbit coupling. As a result of the giant spin Hall effect in β -W and careful magnetic annealing, we significantly reduce the critical current density for the spin-transfer-torque-induced magnetic switching in Co40Fe40B20 . The elemental β -W is a superior candidate for magnetic memory and spin-logic applications.

  5. Solid state proton spin-lattice relaxation in four structurally related organic molecules

    International Nuclear Information System (INIS)

    Beckmann, Peter A.; Burbank, Kendra S.; Lau, Matty M.W.; Ree, Jessica N.; Weber, Tracy L.

    2003-01-01

    We report and interpret the temperature dependence of the proton spin-lattice relaxation rate at 8.50 and 22.5 MHz in four polycrystalline solids composed of structurally related molecules: 2-ethylanthracene, 2-t-butylanthracene, 2-ethylanthraquinone, and 2-t-butylanthraquinone. We have been unable to grow single crystals and therefore do not know the crystal structures. Hence, we use the NMR relaxometry data to make predictions about the solid state structures. As expected, we are able to conclude that the ethyl groups do not reorient in the solid state but that the t-butyl groups do. The anthraquinones have a ''simpler'' structure than the anthracenes. The best dynamical models suggest that there is a unique crystallographic site for the t-butyl groups in 2-t-butylanthraquinone and two sites, each with half the molecules, for the ethyl groups in 2-ethylanthraquinone. There are also two sites in 2-ethylanthracene, but with unequal weights, suggesting four sites in the unit cell with lower symmetry than the two anthraquinones. Finally, the observed relaxation rate data in 2-t-butylanthracene is very complex and its interpretation demonstrates the uniqueness problem that arises in interpreting relaxometry data without the knowledge of the crystal structure

  6. 5 CFR 335.104 - Eligibility for career ladder promotion.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Eligibility for career ladder promotion. 335.104 Section 335.104 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PROMOTION AND INTERNAL PLACEMENT General Provisions § 335.104 Eligibility for career ladder...

  7. Ladders to Literacy. What Works Clearinghouse Intervention Report

    Science.gov (United States)

    What Works Clearinghouse, 2013

    2013-01-01

    "Ladders to Literacy" is a supplemental early literacy curriculum composed of 60 activities designed to develop children's print/book awareness, metalinguistic awareness, and oral language skills. The "Ladders to Literacy" activities can be implemented in a variety of early childhood settings and adapted for children with…

  8. 29 CFR 1910.25 - Portable wood ladders.

    Science.gov (United States)

    2010-07-01

    ... which dimensions are specified should not be used by more than one man at a time nor with ladder jacks... step spacing shall be employed which shall be not more than 12 inches. Steps shall be parallel and...) [Reserved] (x) Ladders shall be inspected frequently and those which have developed defects shall be...

  9. Hyperfine structure, nuclear spins and magnetic moments of some cesium isotopes

    International Nuclear Information System (INIS)

    Ekstroem, C.; Ingelman, S.; Wannberg, G.

    1977-03-01

    Using an atomic-beam magnetic resonance apparatus connected on-line with the ISOLDE isotope separator, CERN, hyperfine structure measurements have been performed in the 2 Ssub(1/2) electronic ground state of some cesium isotopes. An on-line oven system which efficiently converts a mass separated ion-beam of alkali isotopes to an atomic beam is described in some detail. Experimentally determined nuclear spins of sup(120, 121, 121m, 122, 122m, 123, 124, 126, 128, 130m, 135m)Cs and magnetic moments of sup(122, 123, 124, 126, 128, 130)Cs are reported and discussed in terms of different nuclear models. The experimental data indicate deformed nuclear shapes of the lightest cesium isotopes. (Auth.)

  10. Microbeads detection using Planar Hall effect in spin-valve structure

    International Nuclear Information System (INIS)

    Thanh, N.T.; Kim, K.W.; Kim, C.O.; Shin, K.H.; Kim, C.G.

    2007-01-01

    The Planar Hall effect in a spin-valve structure of Ta/NiFe/CoFe/Cu/CoFe/IrMn/Ta has been applied as a biosensor being capable of detecting Dynabeads ( R) M-280. The patterns with a size of 50x100μm 2 were prepared by lithography methods, and the biosensor performance was tested under the application of a DC magnetic field where the output signals were obtained from a nanovoltmeter. The sensor signal has produced high sensitivity results; especially, the real-time profiles revealed stable and significant signals at external applied magnetic field of around 7.0Oe with the resolution of 0.04 beads per μm 2 . With these results, it could be feasible to detect some commercial Dynabeads ( R) M-280 which can be used for recognition force and biomolecular interaction measurements

  11. Measurement of the spin-dependent structure function g$_{1}$(x) of the proton

    CERN Document Server

    Adams, D.; Arik, E.; Arvidson, A.; Badelek, B.; Ballintijn, M.K.; Bardin, G.; Baum, Guenter; Berglund, P.; Betev, L.; Bird, I.G.; Birsa, R.; Bjorkholm, P.; Bonner, B.E.; de Botton, N.; Bradamante, F.; Bressan, A.; Brull, A.; Bueltmann, Stephen L.; Burtin, E.; Cavata, C.; Clocchiatti, M.; Corcoran, M.D.; Crabb, D.; Cranshaw, J.; Crawford, M.; Cuhadar, T.; Dalla Torre, S.; van Dantzig, R.; Dhawan, S.; Dulya, C.; Dyring, A.; Eichblatt, S.; Faivre, J.C.; Fasching, D.; Feinstein, F.; Fernandez, C.; Frois, B.; Garzon, J.A.; Gaussiran, T.; Giorgi, M.; von Goeler, E.; Gracia, G.; de Groot, N.; Grosse Perdekamp, M.; Gulmez, Erhan; von Harrach, D.; Hasegawa, T.; Hautle, P.; Hayashi, N.; Heusch, C.A.; Horikawa, N.; Hughes, V.W.; Igo, G.; Ishimoto, S.; Iwata, T.; Kabuss, E.M.; Kaiser, R.; Karev, A.; Kessler, H.J.; Ketel, T.J.; Kishi, A.; Kiselev, Yu.; Klostermann, L.; Kramer, D.; Krivokhijine, V.; Kukhtin, V.; Kyynarainen, J.; Lamanna, M.; Landgraf, U.; Lau, K.; Layda, T.; Le Goff, J.M.; Lehar, F.; de Lesquen, A.; Lichtenstadt, J.; Lindqvist, T.; Litmaath, M.; Lopez-Ponte, S.; Lowe, M.; Magnon, A.; Mallot, G.K.; Marie, F.; Martin, A.; Martino, J.; Matsuda, T.; Mayes, B.; McCarthy, J.S.; Medved, K.; van Middelkoop, G.; Miller, D.; Mori, K.; Moromisato, J.; Nagaitsev, A.; Nassalski, J.; Naumann, L.; Niinikoski, T.O.; Oberski, J.E.J.; Parks, D.P.; Penzo, A.; Perez, G.; Kunne, F.; Peshekhonov, D.; Piegaia, R.; Pinsky, Lawrence S.; Platchkov, S.; Plo, M.; Pose, D.; Postma, H.; Pretz, J.; Pussieux, T.; Pyrlik, J.; Reyhancan, I.; Rieubland, J.M.; Rijllart, A.; Roberts, J.B.; Rock, S.; Rodriguez, M.; Rondio, E.; Rosado, A.; Sabo, I.; Saborido, J.; Sandacz, A.; Savin, Igor A.; Schiavon, P.; Schuler, P.; Segel, R.; Seitz, R.; Semertzidis, Y.; Sever, F.; Shanahan, P.; Shumeiko, N.; Smirnov, G.; Staude, A.; Steinmetz, A.; Stiegler, U.; Stuhrmann, H.; Teichert, K.M.; Tessarotto, F.; Velasco, M.; Vogt, J.; Voss, R.; Weinstein, R.; Whitten, C.; Windmolders, R.; Willumeit, R.; Wislicki, W.; Witzmann, A.; Zanetti, A.M.; Zhao, J.; the SMC

    1994-01-01

    Abstract : We have measured the spin-dependent structure function g_1^p of the proton in deep inelastic scattering of polarized muons off polarized protons, in the kinematic range 0.003

  12. Measurement of the longitudinal deuteron spin-structure function in deep-inelastic scattering

    International Nuclear Information System (INIS)

    Bauer, J.M.

    1996-09-01

    Experiment E143 at SLAC performed deep-inelastic scattering measurements with polarized electrons incident on polarized protons and deuterons. The data for the beam energy of 29 GeV cover the kinematical range of x Bj > 0.03 and 1 2 2 . From these data, the spin-dependent structure functions g 1 were determined. This dissertation describes the experiment and its analysis and discusses the results. The measured integral of g 1 d over x from x = 0 to x = 1 is Γ 1 d = 0.046 ± 0.003 (stat)±0.004 (syst) at Q 2 = 3 GeV 2 and disagrees by more than three standard deviations with the prediction of the Ellis-Jaffe, sum rule. The data suggest that the quark contribution to the nucleon helicity is 0.35 ± 0.05. From the proton data of the same experiment, the integral over the proton spin-structure functional g 1 d was determined to be Γ 1 p = 0.127 ± 0.003(stat)±0.008(syst). By Combining the deuteron data with the proton data, the integral Γ 1 n was extracted as -0.027 ± 0.008 (stat)±0.010 (syst). The integral Γ 1 p - Γ 1 n is 0.154±0.010(stat) ±0.016 (syst) according to the E143 analysis. This result agrees with the important Bjorken sum rule of 0.171 ± 0.009 at Q 2 = 3 GeV 2 within less than one standard deviation. Furthermore, results of a separate analysis involving GLAP evolution equations are shown. Data were also collected for beam energies of 16.2 and 9.7 GeV, Results for g 1 at these energies are presented

  13. Competing effect of spin-orbit torque terms on perpendicular magnetization switching in structures with multiple inversion asymmetries

    OpenAIRE

    Yu, Guoqiang; Akyol, Mustafa; Upadhyaya, Pramey; Li, Xiang; He, Congli; Fan, Yabin; Montazeri, Mohammad; Alzate, Juan G.; Lang, Murong; Wong, Kin L.; Khalili Amiri, Pedram; Wang, Kang L.

    2016-01-01

    Current-induced spin-orbit torques (SOTs) in structurally asymmetric multilayers have been used to efficiently manipulate magnetization. In a structure with vertical symmetry breaking, a damping-like SOT can deterministically switch a perpendicular magnet, provided an in-plane magnetic field is applied. Recently, it has been further demonstrated that the in-plane magnetic field can be eliminated by introducing a new type of perpendicular field-like SOT via incorporating a lateral structural a...

  14. Magic Angle Spinning NMR Structure Determination of Proteins from Pseudocontact Shifts

    KAUST Repository

    Li, Jianping

    2013-06-05

    Magic angle spinning solid-state NMR is a unique technique to study atomic-resolution structure of biomacromolecules which resist crystallization or are too large to study by solution NMR techniques. However, difficulties in obtaining sufficient number of long-range distance restraints using dipolar coupling based spectra hamper the process of structure determination of proteins in solid-state NMR. In this study it is shown that high-resolution structure of proteins in solid phase can be determined without the use of traditional dipolar-dipolar coupling based distance restraints by combining the measurements of pseudocontact shifts (PCSs) with Rosetta calculations. The PCSs were generated by chelating exogenous paramagnetic metal ions to a tag 4-mercaptomethyl-dipicolinic acid, which is covalently attached to different residue sites in a 56-residue immunoglobulin-binding domain of protein G (GB1). The long-range structural restraints with metal-nucleus distance of up to ∼20 Å are quantitatively extracted from experimentally observed PCSs, and these are in good agreement with the distances back-calculated using an X-ray structure model. Moreover, we demonstrate that using several paramagnetic ions with varied paramagnetic susceptibilities as well as the introduction of paramagnetic labels at different sites can dramatically increase the number of long-range restraints and cover different regions of the protein. The structure generated from solid-state NMR PCSs restraints combined with Rosetta calculations has 0.7 Å root-mean-square deviation relative to X-ray structure. © 2013 American Chemical Society.

  15. Singularities of the dynamical structure factors of the spin-1/2 XXX chain at finite magnetic field

    Science.gov (United States)

    Carmelo, J. M. P.; Sacramento, P. D.; Machado, J. D. P.; Campbell, D. K.

    2015-10-01

    We study the longitudinal and transverse spin dynamical structure factors of the spin-1/2 XXX chain at finite magnetic field h, focusing in particular on the singularities at excitation energies in the vicinity of the lower thresholds. While the static properties of the model can be studied within a Fermi-liquid like description in terms of pseudoparticles, our derivation of the dynamical properties relies on the introduction of a form of the ‘pseudofermion dynamical theory’ (PDT) of the 1D Hubbard model suitably modified for the spin-only XXX chain and other models with two pseudoparticle Fermi points. Specifically, we derive the exact momentum and spin-density dependences of the exponents {{\\zeta}τ}(k) controlling the singularities for both the longitudinal ≤ft(τ =l\\right) and transverse ≤ft(τ =t\\right) dynamical structure factors for the whole momentum range k\\in ]0,π[ , in the thermodynamic limit. This requires the numerical solution of the integral equations that define the phase shifts in these exponents expressions. We discuss the relation to neutron scattering and suggest new experiments on spin-chain compounds using a carefully oriented crystal to test our predictions.

  16. Ground-state and spectral properties of an asymmetric Hubbard ladder

    Science.gov (United States)

    Abdelwahab, Anas; Jeckelmann, Eric; Hohenadler, Martin

    2015-04-01

    We investigate a ladder system with two inequivalent legs, namely, a Hubbard chain and a one-dimensional electron gas. Analytical approximations, the density-matrix renormalization group method, and continuous-time quantum Monte Carlo simulations are used to determine ground-state properties, gaps, and spectral functions of this system at half-filling. Evidence for the existence of four different phases as a function of the Hubbard interaction and the rung hopping is presented. First, a Luttinger liquid exists at very weak interchain hopping. Second, a Kondo-Mott insulator with spin and charge gaps induced by an effective rung exchange coupling is found at moderate interchain hopping or strong Hubbard interaction. Third, a spin-gapped paramagnetic Mott insulator with incommensurate excitations and pairing of doped charges is observed at intermediate values of the rung hopping and the interaction. Fourth, the usual correlated band insulator is recovered for large rung hopping. We show that the wave numbers of the lowest single-particle excitations are different in each insulating phase. In particular, the three gapped phases exhibit markedly different spectral functions. We discuss the relevance of asymmetric two-leg ladder systems as models for atomic wires deposited on a substrate.

  17. A Precision Measurement of the Spin Structure of the Proton at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Erbacher, Robin D

    1999-09-22

    E143 at SLAC Endstation A performed deep-inelastic scattering measurements of polarized electrons from polarized protons and deuterons within cryogenic {sup 15}NH{sub 3} and {sup 15}ND{sub 3}, respectively. Data were taken at incident energies of 29.1, 16.2 and 9.7 GeV, and covered the kinematical range x > 0:03 and 0:3 < Q{sup 2} < 12 (GeV/c){sup 2}. The scattered electrons were detected by two spectrometers at angles of 4.5{sup o} and 7.0{sup o}. From these data, the spin-dependent structure functions g{sub 1}{sup p}(x; Q{sup 2}) and g{sub 1}{sup d}(x; Q{sup 2}) were determined. This dissertation describes the experiment, with emphasis on the results on the proton spin structure. The integral of g{sub 1} over the range 0 < x < 1 was found to be {Gamma}{sub 1}{sup p} = 0.130 {+-} 0.003 {+-} 0.008 for the proton and {Gamma}{sub 1}{sup d} = 0.044 {+-} 0.003 {+-} 0.004 for the deuteron. Both values are in agreement with world data, and violate the Ellis-Jaffe sum rule by more than 3 standard deviations. The neutron structure function was obtained by combining proton and deuteron results, giving {Gamma}{sub 1}{sup n} = [0.035 {+-} 0.007 {+-} 0.010]. From this the integral {Gamma}{sub 1}{sup p}-{Gamma}{sub 1}{sup n} followed, yielding 0.165 {+-} 0.009 {+-} 0.016 at Q{sup 2} = 3 (GeV/c){sup 2}, in agreement with the Bjorken sum rule to within one standard deviation. The Q{sup 2}-dependence of the ratio g{sub 1}/F{sub 1} was determined to be small for Q{sup 2} > 1 (GeV/c){sup 2}, validating the assumption of no Q{sup 2}-dependence used in obtaining the integrals. A small rise with increasing Q{sup 2} was seen in the ratio for Q{sup 2} < 1 (GeV/c){sup 2}, however. The total quark contribution to the spin was found to be {Delta}q = 0.28 {+-} 0.09 for the proton, and {Delta}q = 0.32 {+-} 0.05 for the deuteron. Furthermore, a large negative spin contribution from the strange sea quarks was measured for both nucleons, giving {Delta}s = 0.10 {+-} 0.03 and {Delta}s = -0

  18. Spin glasses

    International Nuclear Information System (INIS)

    Fischer, K.H.; Hertz, J.A.

    1993-01-01

    Spin glasses, simply defined by the authors as a collection of spins (i.e., magnetic moments) whose low-temperature state is a frozen disordered one, represent one of the fascinating new fields of study in condensed matter physics, and this book is the first to offer a comprehensive account of the subject. Included are discussions of the most important developments in theory, experimental work, and computer modeling of spin glasses, all of which have taken place essentially within the last two decades. The first part of the book gives a general introduction to the basic concepts and a discussion of mean field theory, while the second half concentrates on experimental results, scaling theory, and computer simulation of the structure of spin glasses

  19. Structural changes induced spin-reorientation of ultrathin Mn films grown on Ag(001)

    International Nuclear Information System (INIS)

    Ouarab, N.; Haroun, A.; Baadji, N.

    2016-01-01

    The strained body centered tetragonal (bct) Mn ultrathin film from lattice parameter a=2.89 Å to lattice value of 2.73 Å induces anti-ferromagnetic behavior between Mn layers. The magnetic easy axis of Mn film was demonstrated theoretically to switch from the in-plane to out-of-plane by magneto-optical Kerr effect investigation. By including spin–orbit coupling in full potential linearized augmented plane waves and linearized muffin-tin orbitals methods, manganese ultrathin film displays different magnetic behaviors and the spin-reorientation transition is shown to be correlated to these structural changes. The calculated magnetic moment of manganese planes are enhanced and reach a value of ~4.02 μ B . The polar magneto-optical Kerr effect is calculated for a photon energy range extended to 15 eV. It shows a pronounced peak in visible light. - Highlights: • The applied strain in Mn-bct structure induces anti-ferromagnetic behavior. • The easy magnetization axis is demonstrated to be out-of-plane. • The magnetic moment of Mn-layers are enhanced and reach a value of ~4.02 μ B . • Kerr spectra show significant polar responses for Mn films in the visible range. • The prominent structures in the Kerr spectra have been identified.

  20. Structural changes induced spin-reorientation of ultrathin Mn films grown on Ag(001)

    Energy Technology Data Exchange (ETDEWEB)

    Ouarab, N., E-mail: ouarab_nourdine@yahoo.fr [Quantum Physics and Dynamical Systems Laboratory, Ferhat Abbas University of Sétif (Algeria); Semiconductor Technology Research Center for Energetic-(CRTSE), 02, Bd Frantz Fanon Algiers, BP N° 140 (Algeria); Haroun, A. [Quantum Physics and Dynamical Systems Laboratory, Ferhat Abbas University of Sétif (Algeria); Baadji, N. [School of Physics and CRANN, Trinity College, Dublin 2 (Ireland)

    2016-12-01

    The strained body centered tetragonal (bct) Mn ultrathin film from lattice parameter a=2.89 Å to lattice value of 2.73 Å induces anti-ferromagnetic behavior between Mn layers. The magnetic easy axis of Mn film was demonstrated theoretically to switch from the in-plane to out-of-plane by magneto-optical Kerr effect investigation. By including spin–orbit coupling in full potential linearized augmented plane waves and linearized muffin-tin orbitals methods, manganese ultrathin film displays different magnetic behaviors and the spin-reorientation transition is shown to be correlated to these structural changes. The calculated magnetic moment of manganese planes are enhanced and reach a value of ~4.02 μ{sub B}. The polar magneto-optical Kerr effect is calculated for a photon energy range extended to 15 eV. It shows a pronounced peak in visible light. - Highlights: • The applied strain in Mn-bct structure induces anti-ferromagnetic behavior. • The easy magnetization axis is demonstrated to be out-of-plane. • The magnetic moment of Mn-layers are enhanced and reach a value of ~4.02 μ{sub B}. • Kerr spectra show significant polar responses for Mn films in the visible range. • The prominent structures in the Kerr spectra have been identified.

  1. Annealing effect on spin density of broken bonds and on the structure of amorphous germanium

    International Nuclear Information System (INIS)

    Bukhan'ko, F.N.; Okunev, V.D.; Samojlenko, Z.A.

    1989-01-01

    Dependence of volumetric spin density of broken bonds in a-Ge films, produced by cathode sputtering in argon, on the annealing temperature is investigated by ESR method. The film structure is controlled by the X-ray method. Two ESR lines with g=2.019 and g=2.003, their intensities changing non-monotonously with annealing temperature are observed. The line with g=2.019 is typical of only amorphous germanium state, and the line with g=2.003 is preserved after film crystallization. Under comparison of results with structural data a conclusion is made that the observed lines in ESR spectra are linked with broken bonds in peripheral regions of two types of clusters. The line with g=2.003 is conditioned by broken bonds in the peripheral cluster regions with standard cubic atom packing and the line with g=2.019 is linked with clusters of hexagonal type which is not typical of crystalline germanium standard structure

  2. Spin-echo small-angle neutron scattering study of the structure organization of the chromatin in biological cell

    NARCIS (Netherlands)

    Iashina, E.G.; Bouwman, W.G.; Duif, C.P.; Filatov, M.V.; Grigoriev, S. V.

    2017-01-01

    Spin-echo small-angle scattering (SESANS) technique is a method to measure the structure of materials from nano- to micrmeter length scales. This method could be important for studying the packaging of DNA in the eukaryotic cell. We measured the SESANS function from chicken erythrocyte nuclei

  3. Final COMPASS results on the deuteron spin-dependent structure function g(1)(d) and the Bjorken sum rule

    Czech Academy of Sciences Publication Activity Database

    Adolph, C.; Aghasyan, M.; Akhunzyanov, R.; Alexeev, M.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anfimov, N. V.; Anosov, V.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bodlák, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chung, S.U.; Cicuttin, A.; Crespo, M.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; Dhara, L.; Donskov, S. V.; Doshita, N.; Dreisbach, Ch.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Giarra, J.; Giordano, A.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse-Perdekapm, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F. H.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Yu.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jarý, V.; Joosten, R.; Jörg, P.; Kabuss, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G. K.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, M.; Meyer, W.; Mikhailov, Yu. V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W. D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Roskot, M.; Rossiyskaya, N. S.; Ryabchikov, D.; Rybnikov, A.; Rychter, A.; Salač, R.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolík, J.; Srnka, Aleš; Steffen, D.; Stolarski, M.; Subrt, O.; Šulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Thiel, A.; Tosello, F.; Tskhay, V.; Uhl, S.; Vauth, A.; Veloso, J.; Virius, M.; Vondra, J.; Wallner, S.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Ter Wolbeek, J.; Zaremba, K.; Závada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.; Zink, A.

    2017-01-01

    Roč. 769, JUNE (2017), s. 34-41 ISSN 0370-2693 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : COMPASS * deep inelastic scattering * spin * structure function * parton helicity distributions Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Nuclear physics Impact factor: 4.807, year: 2016

  4. New insights into the origin of ladder dikes: Implications for punctuated growth and crystal accumulation in the Cathedral Peak granodiorite

    Science.gov (United States)

    Wiebe, R. A.; Jellinek, A. M.; Hodge, K. F.

    2017-04-01

    Ladder dikes are steep tabular bodies, typically a meter or less thick, composed of moderately dipping, concave upward, alternating dark (i.e. schlieren) and light bands oriented roughly perpendicular to the ladder dike margins. These structures occur widely but sparsely in granitic rocks and are found prominently in the Cathedral Peak granodiorite (CPG) of the Tuolumne Intrusive suite. Previous studies have interpreted that ladder dikes form as a result of processes including the downward flow of crystal mush in cracks within strong crystal mush or by upward flow in steep tubes that migrate within a strong crystal mush. Our new observations indicate that ladder dikes formed by downward flow of crystal mush in troughs or valleys, in a manner potentially comparable to trough bands in mafic layered intrusions. Extensions of the schlieren outward and upward away from the ladder dike margins into the host granite demonstrate that the host granite was deposited as mounds on both sides at the same time as the ladder dikes. Ladder dikes, therefore, record lateral flows of crystal mush on a magma chamber floor. Vertical exposures suggest these flows are on the order of ten meters thick. Some steep exposures on granite domes indicate multiple ladder dikes (and flows) over a stratigraphic height of 80-100 m. Later (stratigraphically higher) flows commonly deform and erode the top of an earlier flow, and granitic material rich in K-feldspar megacrysts has locally engulfed large blocks of ladder dikes, demonstrating that the megacrysts were also transported in flows. Flows in the CPG are directed away from the center of the pluton toward the western and eastern margins and apparently spread along a strong crystal mush floor and into a rheologically complex CPG magma. Whereas established dynamical models for spreading (single phase) gravity currents with simple and complex rheologies explain the elongate geometry, spacing and orientation of the tabular bodies, the origin and

  5. Critical current density for spin transfer torque switching with composite free layer structure

    OpenAIRE

    You, Chun-Yeol

    2009-01-01

    Critical current density of composite free layer (CFL) in magnetic tunneling junction is investigated. CFL consists of two exchange coupled ferromagnetic layers, where the coupling is parallel or anti-parallel. Instability condition of the CFL under the spin transfer torque, which is related with critical current density, is obtained by analytic spin wave excitation model and confirmed by macro-spin Landau-Lifshitz-Gilbert equation. The critical current densities for the coupled two identical...

  6. Selectivity of fish ladders: a bottleneck in Neotropical fish movement

    Directory of Open Access Journals (Sweden)

    Carlos Sérgio Agostinho

    Full Text Available Although dozens of fish ladders have been constructed at dams of Brazilian reservoirs, there are few studies evaluating their efficiency as a tool for the conservation of Neotropical ichthyofauna, especially for migratory species. Therefore, the present study evaluated the selectivity of the species that entered and ascended the fish ladder located next to Lajeado Dam (Luis Eduardo Magalhães Hydroelectric Power Plant on the Tocantins River. Samples were taken monthly from November, 2002 through October, 2003, in the resting pools of the ladder, using cast nets, and in the downstream stretch, using gillnets. The selectivity of the ladder in attracting fish was evaluated by comparing the occurrence, relative abundance, dominance and the congruence of abundance ranks of migratory and non-migratory species in the ladder and in the stretch of river immediately downstream. Species richness and fish abundance in the resting pools were used to evaluate selectivity along the ladder. The effects on selectivity by temporal variations in water level downriver and maximum flow velocity in the fish ladder were also analyzed. Out of the 130 species recorded downriver, 62.3% were caught in the ladder, and migratory species were clearly favored. However, more than 2/3 of the catch belonged to only three species (Rhaphiodon vulpinus, Psectrogaster amazonica and Oxydoras niger. Although the majority of the species that entered the ladder were able to reach its top, there was a sharp reduction in abundance of individuals towards the top. Temporal variations in the water level below the dam influenced richness and abundance of fish concentrated downstream and in the ladder, with lower values during periods of low water. In the ladder, a maximum flow velocity of 2.3 m/s, although also selective, proved to be more appropriate for fish ascension than a velocity of 2.8 m/s. It was concluded that the entry and ascension of the fish in the ladder were not congruent with

  7. Electron spin interactions in chemistry and biology fundamentals, methods, reactions mechanisms, magnetic phenomena, structure investigation

    CERN Document Server

    Likhtenshtein, Gertz

    2016-01-01

    This book presents the versatile and pivotal role of electron spin interactions in nature. It provides the background, methodologies and tools for basic areas related to spin interactions, such as spin chemistry and biology, electron transfer, light energy conversion, photochemistry, radical reactions, magneto-chemistry and magneto-biology. The book also includes an overview of designing advanced magnetic materials, optical and spintronic devices and photo catalysts. This monograph appeals to scientists and graduate students working in the areas related to spin interactions physics, biophysics, chemistry and chemical engineering.

  8. Structural Asymmetry-Facilitated Tunability of Spin Distribution in the (10, 0) Carbon Nanotube Induced by Charging

    Science.gov (United States)

    Wang, Jia; Gao, Yang; Zhang, Zhiyuan; Xu, Dexuan; Wang, Zhigang; Zhang, Rui-Qin

    2017-07-01

    Constructing the asymmetric electronic structure of low-dimensional carbon nanomaterials is significant for application of molecular devices, such as magnetic switches. In this work, we use density functional theory to investigate the asymmetric spin distribution in a typical (10, 0) carbon nanotube by capping one end with a fullerene hemisphere and saturating the dangling bonds with hydrogen atoms at the other end. Calculated results indicate that this geometry obviously modified the distribution of spin density along the tube axis, and the electrons present were antiferromagnetically coupled at both ends. Specifically, the change in magnetic order at the end of the cap can be changed with either the increase or decrease of the charge. In addition, the analysis of electron density difference shows that charge induces gain or loss of electrons not only at the open end, but also at the cap end. These findings provide a strategy for controlling spin distribution for nanoscale functional molecular devices through a simple charge adjustment.

  9. Tailoring electronic structure of α-AlH3 to enhance spin polarization: Insights from density functional calculations

    Science.gov (United States)

    Lu, Yi-Lin; Dong, Shengjie; Zhou, Baozeng; Sun, Lili; Zhao, Hui; Wu, Ping

    2017-09-01

    The effects of 3d transition metals doping on the structural, electronic, and magnetic properties of aluminum hydride were investigated based on spin-polarized first-principles calculations. The studies indicated that V, Cr, Mn, and Fe doping could produce polarization of high-spin state, while Co and Ni doping would induce polarization of low-spin state. It was found that the magnetic ground state depended on the distance between two substitutions and the long-range ferromagnetic coupling was achieved upon doping V, Mn, and Fe. The present work indicated that the introduced 3d-block dopants could tailor aluminum hydride into either a potential half-metallic or n-type magnetic semiconductor by tuning the valence electrons of the impurities. The main findings of this work pointed out the possibilities of the applications of hydrides in future hydride electronics and spintronics.

  10. The laddering method in service innovation research

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe

    2017-01-01

    map of what is actually going on in the consumer’s mind when the consumer is buying and consuming specific goods. It is argued, in this chapter, that this understanding is indeed both interesting and relevant in service innovation. More specifically, realizations of consumers’ values will help...... to guide marketers to understand what to innovate, how to innovate, how to plan and efficiently communicate changes, how to sell the innovations in the market place and how to implement organizational changes that innovations might cause. Furthermore, the laddering methodology has been applied across many...... fields with good success and the premises for using the method and for analyzing obtained data, is rather well described. The latter (i.e. premises and data analysis) is often raised as central and critical points of qualitative research methodology when arguing for problems with validity and reliability...

  11. Complex band structures of transition metal dichalcogenide monolayers with spin-orbit coupling effects

    Science.gov (United States)

    Szczęśniak, Dominik; Ennaoui, Ahmed; Ahzi, Saïd

    2016-09-01

    Recently, the transition metal dichalcogenides have attracted renewed attention due to the potential use of their low-dimensional forms in both nano- and opto-electronics. In such applications, the electronic and transport properties of monolayer transition metal dichalcogenides play a pivotal role. The present paper provides a new insight into these essential properties by studying the complex band structures of popular transition metal dichalcogenide monolayers (MX 2, where M  =  Mo, W; X  =  S, Se, Te) while including spin-orbit coupling effects. The conducted symmetry-based tight-binding calculations show that the analytical continuation from the real band structures to the complex momentum space leads to nonlinear generalized eigenvalue problems. Herein an efficient method for solving such a class of nonlinear problems is presented and yields a complete set of physically relevant eigenvalues. Solutions obtained by this method are characterized and classified into propagating and evanescent states, where the latter states manifest not only monotonic but also oscillatory decay character. It is observed that some of the oscillatory evanescent states create characteristic complex loops at the direct band gap of MX 2 monolayers, where electrons can directly tunnel between the band gap edges. To describe these tunneling currents, decay behavior of electronic states in the forbidden energy region is elucidated and their importance within the ballistic transport regime is briefly discussed.

  12. A Precision Measurement of the Spin Structure Function G(2)(P)

    Energy Technology Data Exchange (ETDEWEB)

    Benmouna, N

    2004-01-05

    The spin structure function g{sub 2}(x,Q{sup 2}) and the virtual photon asymmetry A{sub 2}(x,Q{sup 2}) were measured for the proton using deep inelastic scattering. The experiment was conducted at the Stanford Linear Accelerator Center (SLAC), where longitudinally polarized electrons at 29.1 and 32.3 GeV were scattered from a transversely polarized NH{sub 3} target. Large data sets were accumulated using three independent spectrometers covering a kinematic range 0.02 {le} x {le} 0.8 and 1 {le} Q{sup 2} {le} 20 (GeV/c){sup 2}. This new data is the first data precise enough to distinguish between current models for the proton. The structure function g{sub 2}{sup p} was found to be reasonably consistent with the twist-2 Wandzura-Wilczek calculation. The Q{sup 2} dependence of g{sub 2} approximately follows the Q{sup 2} dependence of g{sub 2}{sup WW}, although the data are not precise enough to rule out no Q{sup 2} dependence. The absolute value for A{sub 2}{sup p} was found to be significantly smaller than the Soffer limit over the measured range. The virtual photon asymmetry A{sub 2} was also found to be inconsistent with zero over much of the measured range.

  13. Structure and spin dynamics of multiferroic BiFeO3

    Science.gov (United States)

    Park, Je-Geun; Le, Manh Duc; Jeong, Jaehong; Lee, Sanghyun

    2014-10-01

    Multiferroic materials have attracted much interest due to the unusual coexistence of ferroelectric and (anti-)ferromagnetic ground states in a single compound. They offer an exciting platform for new physics and potentially novel devices. BiFeO3 is one of the most celebrated multiferroic materials and has highly desirable properties. It is the only known room-temperature multiferroic with TC ≈ 1100 K and TN ≈ 650 K, and exhibits one of the largest spontaneous electric polarisations, P ≈ 80 µC cm-2. At the same time, it has a magnetic cycloid structure with an extremely long period of 620 Å, which arises from competition between the usual symmetric exchange interaction and the antisymmetric Dzyaloshinskii-Moriya (DM) interaction. There is also an intriguing interplay between the DM interaction and single ion anisotropy K. In this review, we have attempted to paint a complete picture of bulk BiFeO3 by summarising the structural and dynamic properties of both the spin and lattice parts and their magneto-electric coupling.

  14. Spin-filter effect in normal metal/ferromagnetic insulator/normal metal/superconductor structures

    International Nuclear Information System (INIS)

    Li, Hong; Yang, Wei; Yang, Xinjian; Qin, Minghui; Guo, Jianqin

    2007-01-01

    Taking into account the thickness of the ferromagnetic insulator, the spin-filter effect in normal metal/ferromagnetic insulator/normal metal/superconductor (NM/FI/NM/SC) junctions is studied based on the Blonder-Tinkham-Klapwijk (BTK) theory. It is shown that a spin-dependent energy shift during the tunneling process induces splitting of the subgap resonance peaks. The spin polarization due to the spin-filter effect of the FI causes an imbalance of the peaks heights and can enhance the Zeeman splitting of the gap peaks caused by an applied magnetic field. The spin-filter effect has no contribution to the proximity-effect-induced superconductivity in NM interlayer

  15. Nonreciprocity of spin waves in magnonic crystals created by surface acoustic waves in structures with yttrium iron garnet

    Energy Technology Data Exchange (ETDEWEB)

    Kryshtal, R.G.; Medved, A.V., E-mail: avm@ms.ire.rssi.ru

    2015-12-01

    Experimental results of investigations of nonreciprocity for surface magnetostatic spin waves (SMSW) in the magnonic crystal created by surface acoustic waves (SAW) in yttrium iron garnet films on a gallium gadolinium garnet substrate as without metallization and with aluminum films with different electrical conductivities (thicknesses) are presented. In structures without metallization, the frequency of magnonic gaps is dependent on mutual directions of propagation of the SAW and SMSW, showing nonreciprocal properties for SMSW in SAW – magnonic crystals even with the symmetrical dispersion characteristic. In metalized SAW – magnonic crystals the shift of the magnonic band gaps frequencies at the inversion of the biasing magnetic field was observed. The frequencies of magnonic band gaps as functions of SAW frequency are presented. Measured dependencies, showing the decrease of magnonic gaps frequency and the expansion of the magnonic band gap width with the decreasing of the metal film conductivity are given. Such nonreciprocal properties of the SAW – magnonic crystals are promising for signal processing in the GHz range. - Highlights: • Spin waves nonreciprocity in YIG magnonic crystals with SAW was studied. • SAW was shown to create nonreciprocity for spin waves in YIG–GGG even without metal. • Frequency and width of magnonic band gaps were measured versus metal conductivity. • Conductivity for practical use of spin waves in the structure YIG–metal was defined.

  16. Piezotronic Effect on Rashba Spin-Orbit Coupling in a ZnO/P3HT Nanowire Array Structure.

    Science.gov (United States)

    Zhu, Laipan; Zhang, Yan; Lin, Pei; Wang, Ying; Yang, Leijing; Chen, Libo; Wang, Longfei; Chen, Baodong; Wang, Zhong Lin

    2018-02-27

    A key concept in the emerging field of spintronics is the voltage-gate control of spin precession via the effective magnetic field generated by the Rashba spin-orbit coupling (SOC). Traditional external gate voltage usually needs a power supply, which can easily bring about background noise or lead to a short circuit in measurement, especially for nanoscale spintronic devices. Here, we present a study on the circular photogalvanic effect (CPGE) in a ZnO/P3HT nanowire array structure with the device excited under oblique incidence. We demonstrate that a strong Rashba SOC is induced by the structure inversion asymmetry of the ZnO/P3HT heterointerface. We show that the Rashba SOC can be effectively tuned by inner-crystal piezo-potential created inside the ZnO nanowires instead of an externally applied voltage. The piezo-potential can not only ensure the stability of future spin-devices under a static pressure or strain but also work without the need of extra energy; hence this room-temperature generation and piezotronic effect control of spin photocurrent demonstrate a potential application in large-scale flexible spintronics in piezoelectric nanowire systems.

  17. The Spin Structure Function $g_1^{\\rm p}$ of the Proton and a Test of the Bjorken Sum Rule

    CERN Document Server

    Adolph, C.; Alexeev, M.G.; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Buchele, M.; Burtin, E.; Capozza, L.; Chang, W.C.; Chiosso, M.; Choi, I.; Chung, S.U.; Cicuttin, A.; Crespo, M.L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Duic, V.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Ferrero, A.; Finger, M.; M. Finger jr; Fischer, H.; Franco, C.; von Hohenesche, N. du Fresne; Friedrich, J.M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grabmuller, S.; Grasso, A.; Grosse-Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; von Harrach, D.; Hashimoto, R.; Heinsius, F.H.; Herrmann, F.; Hinterberger, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.Yu; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jorg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.; Kramer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z.V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Lednev, A.A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Marchand, C.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neyret, D.; Nikolaenko, V.I.; Novy, J.; Nowak, W.D.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.C.; Pereira, F.; Pesek, M.; Peshekhonov, D.V.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rocco, E.; Rossiyskaya, N.S.; Ryabchikov, D.I.; Rychter, A.; Samoylenko, V.D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schonning, K.; Schopferer, S.; Selyunin, A.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sozzi, F.; Srnka, A.; Stolarski, M.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Wolbeek, J. ter; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tosello, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

    2016-02-10

    New results for the double spin asymmetry $A_1^{\\rm p}$ and the proton longitudinal spin structure function $g_1^{\\rm p}$ are presented. They were obtained by the COMPASS collaboration using polarised 200 GeV muons scattered off a longitudinally polarised NH$_3$ target. The data were collected in 2011 and complement those recorded in 2007 at 160\\,GeV, in particular at lower values of $x$. They improve the statistical precision of $g_1^{\\rm p}(x)$ by about a factor of two in the region $x\\lesssim 0.02$. A next-to-leading order QCD fit to the $g_1$ world data is performed. It leads to a new determination of the quark spin contribution to the nucleon spin, $\\Delta \\Sigma$ ranging from 0.26 to 0.36, and to a re-evaluation of the first moment of $g_1^{\\rm p}$. The uncertainty of $\\Delta \\Sigma$ is mostly due to the large uncertainty in the present determinations of the gluon helicity distribution. A new evaluation of the Bjorken sum rule based on the COMPASS results for the non-singlet structure function $g_1^{\\rm...

  18. The spin structure function g1p of the proton and a test of the Bjorken sum rule

    Directory of Open Access Journals (Sweden)

    C. Adolph

    2016-02-01

    Full Text Available New results for the double spin asymmetry A1p and the proton longitudinal spin structure function g1p are presented. They were obtained by the COMPASS Collaboration using polarised 200 GeV muons scattered off a longitudinally polarised NH3 target. The data were collected in 2011 and complement those recorded in 2007 at 160 GeV, in particular at lower values of x. They improve the statistical precision of g1p(x by about a factor of two in the region x≲0.02. A next-to-leading order QCD fit to the g1 world data is performed. It leads to a new determination of the quark spin contribution to the nucleon spin, ΔΣ, ranging from 0.26 to 0.36, and to a re-evaluation of the first moment of g1p. The uncertainty of ΔΣ is mostly due to the large uncertainty in the present determinations of the gluon helicity distribution. A new evaluation of the Bjorken sum rule based on the COMPASS results for the non-singlet structure function g1NS(x,Q2 yields as ratio of the axial and vector coupling constants |gA/gV|=1.22±0.05 (stat.±0.10 (syst., which validates the sum rule to an accuracy of about 9%.

  19. Small- and large-x nucleon spin structure from a global QCD analysis of polarized parton distribution functions

    Directory of Open Access Journals (Sweden)

    E.R. Nocera

    2015-03-01

    Full Text Available I investigate the behavior of spin-dependent parton distribution functions in the regions of small and large momentum fractions x. I present a systematic comparison between predictions for relevant observables obtained with various models of nucleon spin structure and a recent global analysis of spin-dependent distributions, NNPDFpol1.1. Together with its unpolarized counterpart, NNPDF2.3, they form a mutually consistent set of parton distributions. Because they include most of the available experimental information, and are determined with a minimally biased methodology, these are especially suited for such a study. I show how NNPDFpol1.1 can discriminate between different theoretical models, even though NNPDF uncertainties remain large near the endpoints x→0 and x→1, due to the lack of experimental information. I discuss how our knowledge of nucleon spin structure may be improved at small x by future measurements at an Electron–Ion Collider, and at large x by recent measurements at Jefferson Lab, also in view of its 12 GeV upgrade.

  20. Calculation of Structural Behavior of Indirect NMR Spin-Spin Couplings in the Backbone of Nucleic Acids

    Czech Academy of Sciences Publication Activity Database

    Sychrovský, Vladimír; Vokáčová, Zuzana; Šponer, Jiří; Špačková, Naďa; Schneider, Bohdan

    2006-01-01

    Roč. 110, č. 45 (2006), s. 22894-22902 ISSN 1520-6106 R&D Projects: GA ČR(CZ) GA203/05/0388; GA MŠk(CZ) LC512 Grant - others:NSF(US) DBI 0110076 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50040507 Keywords : nucleic acids * RNA * DNA * molecular structure Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.115, year: 2006

  1. Magnetic properties and spin structure of MnO single crystal and powder

    Science.gov (United States)

    Sun, X.; Feng, E.; Su, Y.; Nemkovski, K.; Petracic, O.; Brückel, T.

    2017-06-01

    Zero field cooled (ZFC)/Field Cooled (FC) magnetization curves of a bulk MnO single crystal show a peculiar peak at low temperatures (~ 40 K) similar to the low temperature peak observed in MnO nanoparticles. In order to investigate the origin of this peak, the spin structure of a MnO single crystal has been studied and compared with a single phase powder sample using magnetometry and polarized neutron scattering. Both magnetometry and polarized neutron diffraction results confirm the antiferromagnetic (AF) phase transition at the Néel temperature TN of 118 K, in both powder and single crystal form. However, the low temperature peak in the ZFC/FC magnetization curves is not observed in single phase MnO powder. To better understand the observed behavior, ac susceptibility measurements have been employed. We conclude that the clear peak in the magnetic signal from the single crystal originates from a small amount of ferrimagnetic (FiM) Mn2O3 or Mn3O4 impurities, which is grown at the interfaces between MnO crystal twins.

  2. Selectively dispersed isotope labeling for protein structure determination by magic angle spinning NMR

    Energy Technology Data Exchange (ETDEWEB)

    Eddy, Matthew T. [Massachusetts Institute of Technology, Department of Chemistry (United States); Belenky, Marina [Brandeis University, Department of Chemistry (United States); Sivertsen, Astrid C. [Massachusetts Institute of Technology, Francis Bitter Magnet Laboratory (United States); Griffin, Robert G. [Massachusetts Institute of Technology, Department of Chemistry (United States); Herzfeld, Judith, E-mail: herzfeld@brandeis.edu [Brandeis University, Department of Chemistry (United States)

    2013-10-15

    The power of nuclear magnetic resonance spectroscopy derives from its site-specific access to chemical, structural and dynamic information. However, the corresponding multiplicity of interactions can be difficult to tease apart. Complimentary approaches involve spectral editing on the one hand and selective isotope substitution on the other. Here we present a new 'redox' approach to the latter: acetate is chosen as the sole carbon source for the extreme oxidation numbers of its two carbons. Consistent with conventional anabolic pathways for the amino acids, [1-{sup 13}C] acetate does not label {alpha} carbons, labels other aliphatic carbons and the aromatic carbons very selectively, and labels the carboxyl carbons heavily. The benefits of this labeling scheme are exemplified by magic angle spinning spectra of microcrystalline immunoglobulin binding protein G (GB1): the elimination of most J-couplings and one- and two-bond dipolar couplings provides narrow signals and long-range, intra- and inter-residue, recoupling essential for distance constraints. Inverse redox labeling, from [2-{sup 13}C] acetate, is also expected to be useful: although it retains one-bond couplings in the sidechains, the removal of CA-CO coupling in the backbone should improve the resolution of NCACX spectra.

  3. Spin structure of the proton from polarized inclusive deep-inelastic muon-proton scattering

    CERN Document Server

    Adams, D.; Arik, E.; Arvidson, A.; Badelek, B.; Ballintijn, M.K.; Bardin, G.; Baum, Guenter; Berglund, P.; Betev, L.; Bird, I.G.; Birsa, R.; Bjorkholm, P.; Bonner, B.E.; de Botton, N.; Boutemeur, M.; Bradamante, F.; Bravar, A.; Bressan, A.; Bueltmann, Stephen L.; Burtin, E.; Cavata, C.; Crabb, D.; Cranshaw, J.; Cuhadar, T.; Dalla Torre, S.; van Dantzig, R.; Derro, B.; Deshpande, A.; Dhawan, S.; Dulya, C.; Dyring, A.; Eichblatt, S.; Faivre, J.C.; Fasching, D.; Feinstein, F.; Fernandez, C.; Frois, B.; Gallas, A.; Garzon, J.A.; Gaussiran, T.; Giorgi, M.; von Goeler, E.; Gracia, G.; de Groot, N.; Grosse Perdekamp, M.; Gulmez, Erhan; von Harrach, D.; Hasegawa, T.; Hautle, P.; Hayashi, N.; Heusch, C.A.; Horikawa, N.; Hughes, V.W.; Igo, G.; Ishimoto, S.; Iwata, T.; Kabuss, E.M.; Karev, A.; Kessler, H.J.; Ketel, T.J.; Kishi, A.; Kiselev, Yu.; Klostermann, L.; Kramer, D.; Krivokhijine, V.; Kroger, W.; Kurek, K.; Kyynarainen, J.; Lamanna, M.; Landgraf, U.; Layda, T.; Le Goff, J.M.; Lehar, F.; de Lesquen, A.; Lichtenstadt, J.; Lindqvist, T.; Litmaath, M.; Lowe, M.; Magnon, A.; Mallot, G.K.; Marie, F.; Martin, A.; Martino, J.; Matsuda, T.; Mayes, B.; McCarthy, J.S.; Medved, K.; van Middelkoop, G.; Miller, D.; Mori, K.; Moromisato, J.; Nagaitsev, A.; Nassalski, J.; Naumann, L.; Niinikoski, T.O.; Oberski, J.E.J.; Ogawa, A.; Ozben, C.; Parks, D.P.; Penzo, A.; Kunne, F.; Peshekhonov, D.; Piegaia, R.; Pinsky, Lawrence S.; Platchkov, S.; Plo, M.; Pose, D.; Postma, H.; Pretz, J.; Pussieux, T.; Pyrlik, J.; Reyhancan, I.; Rijllart, A.; Roberts, J.B.; Rock, S.; Rodriguez, M.; Rondio, E.; Rosado, A.; Sabo, I.; Saborido, J.; Sandacz, A.; Savin, Igor A.; Schiavon, P.; Schuler, K.P.; Segel, R.; Seitz, R.; Semertzidis, Y.; Sever, F.; Shanahan, P.; Sichtermann, E.P.; Simeoni, F.; Smirnov, G.I.; Staude, A.; Steinmetz, A.; Stiegler, U.; Stuhrmann, H.; Szleper, M.; Teichert, K.M.; Tessarotto, F.; Tlaczala, W.; Trentalange, S.; Unel, G.; Velasco, M.; Vogt, J.; Voss, R.; Weinstein, R.; Whitten, C.; Windmolders, R.; Willumeit, R.; Wislicki, W.; Witzmann, A.; Zanetti, A.M.; Zaremba, K.; Zhao, J.

    1997-01-01

    We have measured the spin-dependent structure function $g_1^{\\rm p}$ in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003 < x < 0.7$ and $1\\gevtwo < Q^2 < 60\\gevtwo$. A next-to-leading order QCD analysis is used to evolve the measured $\\gpone(x,Q^2)$ to a fixed $Q^2_0$. The first moment of $\\gpone$ at $Q^2_0 = 10\\gevtwo$ is $\\gammap = 0.136\\pm 0.013 \\,(\\mbox{stat.}) \\pm 0.009\\,(\\mbox{syst.})\\pm 0.005\\ (\\mbox{evol.})$. This result is below the prediction of the Ellis--Jaffe sum rule by more than two standard deviations. The singlet axial charge $\\dsigt$ is found to be $0.28 \\pm 0.16$. In the Adler--Bardeen factorization scheme, $\\Delta g \\simeq 2$ is required to bring $\\Delta \\Sigma$ in agreement with the Quark-Parton Model. A combined analysis of all available proton and deuteron data confirms the Bjorken sum rule.

  4. Measurement of the Proton and Deuteron Spin Structure Functions g2 and Asymmetry A2

    Energy Technology Data Exchange (ETDEWEB)

    Perry Anthony; R.G. Arnold; Todd Averett; H.R. Band; M.C. Berisso; H. Borel; Peter Bosted; Stephen Bueltmann; M. Buenerd; T. Chupp; Steve Churchwell; G.R. Court; Donald Crabb; Donal Day; Piotr Decowski; P. DePietro; Robin D. Erbacher; R. Erickson; Andrew Feltham; Helene Fonvieille; Emil Frlez; R. Gearhart; V. Ghazikhanian; Javier Gomez; Keith Griffioen; C. Harris; M.A. Houlden; E.W. Hughes; Charles Hyde-Wright; G. Igo; Sebastien Incerti; John Jensen; J.K. Johnson; Paul King; Yu.G. Kolomensky; Sebastian Kuhn; Richard Lindgren; R.M. Lombard-Nelsen; Jacques Marroncle; James Mccarthy; Paul McKee; W. Meyer; Gregory Mitchell; Joseph Mitchell; Michael Olson; S. Penttila; Gerald Peterson; Gerassimos Petratos; R. Pitthan; Dinko Pocanic; R. Prepost; C. Prescott; Liming Qin; Brian Raue; D. Reyna; L.S. Rochester; Stephen Rock; Oscar Rondon-Aramayo; Franck Sabatie; Ingo Sick; T. Smith; L. Sorrell; F. Staley; S. St. Lorant; L.M. Stuart; Z. Szalata; Y. Terrien; William Tobias; Luminita Todor; T. Toole; S. Trentalange; Dieter Walz; Robert Welsh; Frank Wesselmann; T.R. Wright; C.C. Young; Markus Zeier; Hong Guo Zhu; Benedikt Zihlmann

    1999-07-15

    We have measured the spin structure functions g{sub 2}{sup p} and g{sub 2}{sup d} and the virtual photon asymmetries A{sub 2}{sup p} and A{sub 2}{sup d} over the kinematic range 0.02 < x < 0.8 and 1.0 < Q{sup 2} {le} 30(GeV/c){sup 2} by scattering 38.8 GeV longitudinally polarized electrons from transversely polarized NH{sub 3} and {sup 6}LiD targets.The absolute value of A{sub 2} is significantly smaller than the {radical}R positivity limit over the measured range, while g{sub 2} is consistent with the twist-2 Wandzura-Wilczek calculation. We obtain results for the twist-3 reduced matrix elements d{sub 2}{sup p}, d{sub 2}{sup d} and d{sub 2}{sup n}. The Burkhardt-Cottingham sum rule integral (g{sub 2}(x)dx) is reported for the range 0.02 {le} x {le} 0.8.

  5. Carrier and Spin Dynamics in Narrow Gap Parabolic Quantum Well Structures

    Science.gov (United States)

    Bhowmick, M.; Merritt, T.; Khodaparast, G. A.; Mishima, T. D.; Santos, M. B.; Saha, D.; Sanders, G. D.; Stanton, C. J.

    2011-03-01

    Heterostructures with parabolic confinement potentials are important systems to study for many reasons. In a perfect Parabolic Quantum Well (PQW), the subbands are equally spaced and electron-electron interactions are virtually non-existent, allowing coupling of long-wavelength radiation only to the center-of-mass coordinate of the electron system. Narrow band PQW systems are well suited for THz devices because by careful design, one can tune the transition frequency, temperature stability, and narrow-band emission. In our studies, the parabolic confinement was created by an effective parabolic Al compositional gradient inside each well. We studied carrier/spin dynamics in an InSb/AlxIn1 - x Sb multiple- PQW structure using several time resolved differential transmission schemes in the mid-infrared. Our results demonstrate the unique and complex dynamics in InSb heterostructures that can be important for electronic and optoelectronic devices. Supported by: NSF-DMR-0507866, DMR-0520550, DMR-0706313, and NSF-Career Award DMR-0846834.

  6. Implantable bladder volume sensor based on resistor ladder network composed of conductive hydrogel composite.

    Science.gov (United States)

    Mi Kyung Kim; Hyojung Kim; Jung, Yeon Su; Adem, Kenana M A; Bawazir, Sarah S; Stefanini, Cesare; Lee, Hyunjoo J

    2017-07-01

    An accurate bladder volume monitoring system is a critical component in diagnosis and treatment of urological disorders. Here, we report an implantable bladder volume sensor with a multi-level resistor ladder which estimates the bladder volume through discrete resistance values. Discretization allows the sensor output to be resilient to the long-term drift, hysteresis, and degradation of the sensor materials. Our sensor is composed of biocompatible polypyrrole/agarose hydrogel composite. Because Young's modulus of this composite is comparable to that of the bladder wall, the effect of mechanical loading of the sensor on the bladder movement is minimized which allows more accurate volume monitoring. We also demonstrate the patterning and molding capability of this material by fabrication various structures. Lastly, we successfully demonstrate the functionality of the multi-level resistor ladder sensor as a bladder volume sensor by attaching the sensor on the pig's bladder and observing the impedance change of the sensor.

  7. LOFT 3C cable tray and ladder seismic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mosby, W.R.

    1979-03-26

    The LOFT 3C cable tray and ladder were analyzed for LOCE and Safe Shutdown Earthquake (SSE) seismic loads by using equivalent static loads. Design changes were recommended to alleviate overstress conditions.

  8. Log-concavity of the genus polynomials of Ringel Ladders

    Directory of Open Access Journals (Sweden)

    Jonathan L Gross

    2015-10-01

    Full Text Available A Ringel ladder can be formed by a self-bar-amalgamation operation on a symmetric ladder, that is, by joining the root vertices on its end-rungs. The present authors have previously derived criteria under which linear chains of copies of one or more graphs have log-concave genus polyno- mials. Herein we establish Ringel ladders as the first significant non-linear infinite family of graphs known to have log-concave genus polynomials. We construct an algebraic representation of self-bar-amalgamation as a matrix operation, to be applied to a vector representation of the partitioned genus distribution of a symmetric ladder. Analysis of the resulting genus polynomial involves the use of Chebyshev polynomials. This paper continues our quest to affirm the quarter-century-old conjecture that all graphs have log-concave genus polynomials.

  9. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Stuhrmann, H.B. [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1996-11-01

    Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

  10. Fish ladders: safe fish passage or hotspot for predation?

    Directory of Open Access Journals (Sweden)

    Angelo Antonio Agostinho

    Full Text Available Fish ladders are a strategy for conserving biodiversity, as they can provide connectivity between fragmented habitats and reduce predation on shoals that accumulate immediately below dams. Although the impact of predation downstream of reservoirs has been investigated, especially in juvenile salmonids during their downstream movements, nothing is known about predation on Neotropical fish in the attraction and containment areas commonly found in translocation facilities. This study analysed predation in a fish passage system at the Lajeado Dam on the Tocantins River in Brazil. The abundance, distribution, and the permanence (time spent of large predatory fish along the ladder, the injuries imposed by piranhas during passage and the presence of other vertebrate predators were investigated. From December 2002 to October 2003, sampling was conducted in four regions (downstream, along the ladder, in the forebay, and upstream of the reservoir using gillnets, cast nets and counts or visual observations. The captured fish were tagged with thread and beads, and any mutilations were registered. Fish, birds and dolphins were the main predator groups observed, with a predominance of the first two groups. The entrance to the ladder, in the downstream region, was the area with the highest number of large predators and was the only region with relevant non-fish vertebrates. The main predatory fish species were Rhaphiodon vulpinus, Hydrolycus armatus, and Serrasalmus rhombeus. Tagged individuals were detected predating along the ladder for up to 90 days. Mutilations caused by Serrasalmus attacks were noted in 36% of species and 4% of individuals at the top of the ladder. Our results suggested that the high density of fish in the restricted ladder environment, which is associated with injuries suffered along the ladder course and the presence of multiple predator groups with different predation strategies, transformed the fish corridor into a hotspot for

  11. Effects of ladder parameters on asymmetric patterns of force exertion during below-knee amputees climbing ladders.

    Science.gov (United States)

    Li, Weidong; Li, Shiqi; Fu, Yan; Chen, Jacon

    2017-03-01

    Different from walking, ladder climbing requires four-limb coordination and more energy exertion for below-knee amputees (BKAs). We hypothesized that functional deficiency of a disabled limb shall be compensated by the other three intact limbs, showing an asymmetry pattern among limbs. Hand and foot forces of six below-knee amputees and six able-bodied people were collected. Hand, foot and hand/foot sum force variances between groups (non-BKA, intact side and prosthetic side) were carefully examined. Our hypothesis was validated that there is asymmetry between prosthetic and intact side. Results further showed that the ipsilateral hand of the prosthetic leg is stronger than the hand on the intact side, compensating weakness of the prosthetic leg. Effects of ladder rung separations and ladder slant on asymmetric force distribution of BKAs were evaluated, indicating that rung separation has a more significant interactive effect on hand/foot force of BKAs than ladder slant.

  12. Correlation between magnetic spin structure and the three-dimensional geometry in chemically synthesized nanoscale magnetite rings

    DEFF Research Database (Denmark)

    Eltschka, M.; Klaui, M.; Rudiger, U

    2008-01-01

    The correlation between magnetic spin structure and geometry in nanoscale chemically synthesized Fe3O4 rings has been investigated by transmission electron microscopy. We find primarily the flux closure vortex states but in rings with thickness variations, an effective stray field occurs. Using t....... The interaction between exchange coupled rings leads to antiparallel vortex states and extended onion states. (c) 2008 American Institute of Physics....

  13. The g$p\\atop{2}$ Experiment: A Measurement of the Proton's Spin Structure Functions

    Energy Technology Data Exchange (ETDEWEB)

    Zielinski, Ryan B. [Univ. of New Hampshire, Durham, NH (United States)

    2017-09-01

    The E08-027 (g$p\\atop{2}$) experiment measured the spin structure functions of the proton at Jefferson Laboratory in Newport News, Va. Longitudinally polarized electrons were scattered from a transversely and longitudinally polarized solid ammonia target in Hall A, with the polarized NH$_3$ acting as an effective proton target. Focusing on small scattering angle events at the electron energies available at Jefferson Lab, the experiment covered a kinematic phase space of 0.02 GeV$^2$ $< Q^2 <$ 0.20 GeV$^2$ in the proton's resonance region. The spin structure functions, $g_{1}^p(x,Q^2)$ and $g_{2}^p(x,Q^2)$ , are extracted from an inclusive polarized cross section measurement of the electron-proton interaction. Integrated moments of $g_1(x,Q^2)$ are calculated and compared to theoretical predictions made by Chiral Perturbation Theory. The $g_1(x,Q^2)$ results are in agreement with previous measurements, but include a significant increase in statistical precision. The spin structure function contributions to the hyperfine energy levels in the hydrogen atom are also investigated. The $g_2(x,Q^2)$ measured contribution to the hyperfine splitting is the first ever experimental determination of this quantity. The results of this thesis suggest a disagreement of over 100% with previously published model results.

  14. Two-leg ladder systems with dipole–dipole Fermion interactions

    Science.gov (United States)

    Mosadeq, Hamid; Asgari, Reza

    2018-05-01

    The ground-state phase diagram of a two-leg fermionic dipolar ladder with inter-site interactions is studied using density matrix renormalization group (DMRG) techniques. We use a state-of-the-art implementation of the DMRG algorithm and finite size scaling to simulate large system sizes with high accuracy. We also consider two different model systems and explore stable phases in half and quarter filling factors. We find that in the half filling, the charge and spin gaps emerge in a finite value of the dipole–dipole and on-site interactions. In the quarter filling case, s-wave superconducting state, charge density wave, homogenous insulating and phase separation phases occur depend on the interaction values. Moreover, in the dipole–dipole interaction, the D-Mott phase emerges when the hopping terms along the chain and rung are the same, whereas, this phase has been only proposed for the anisotropic Hubbard model. In the half filling case, on the other hand, there is either charge-density wave or charged Mott order phase depends on the orientation of the dipole moments of the particles with respect to the ladder geometry.

  15. Magnetic structure and interactions in the quasi-1D antiferromagnet CaV{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Pieper, Oliver; Lake, Bella [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Berlin (Germany); Technische Universitaet Berlin, Institut fuer Festkoerperphysik, Berlin (Germany); Daoud-Aladine, Aziz [ISIS Facility, Rutherford Appleton Lab., Chilton (United Kingdom); Reehuis, Manfred [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Berlin (Germany); Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Prokes, Karel; Klemke, Bastian; Kiefer, Klaus [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Berlin (Germany); Yan, Jiaqiang; Niazi, Asad; Johnston, David C. [Ames Lab., Departement of Physics and Astronomy, Iowa State University, Ames (United States); Honecker, Andreas [Universitaet Goettingen, Institut fuer Theoretische Physik, Goettingen (Germany)

    2009-07-01

    CaV{sub 2}O{sub 4} is a spin-1 antiferromagnet where the magnetic vanadium ions are arranged on quasi-one-dimensional zig-zag chains with frustrated antiferromagnetic exchange interactions. Here we present high temperature susceptibility and single-crystal neutron diffraction measurements, which are used to deduce the magnetic structure, dominant exchange interactions and orbital configurations. The results suggest that at high temperatures of CaV{sub 2}O{sub 4}, the zig-zags behave as Haldane chains but at low temperatures, orbital ordering lifts the exchange frustration and the zig-zags become spin-1 ladders.

  16. Cavity-induced artificial gauge field in a Bose-Hubbard ladder

    Science.gov (United States)

    Halati, Catalin-Mihai; Sheikhan, Ameneh; Kollath, Corinna

    2017-12-01

    We consider theoretically ultracold interacting bosonic atoms confined to quasi-one-dimensional ladder structures formed by optical lattices and coupled to the field of an optical cavity. The atoms can collect a spatial phase imprint during a cavity-assisted tunneling along a rung via Raman transitions employing a cavity mode and a transverse running wave pump beam. By adiabatic elimination of the cavity field we obtain an effective Hamiltonian for the bosonic atoms, with a self-consistency condition. Using the numerical density-matrix renormalization-group method, we obtain a rich steady-state diagram of self-organized steady states. Transitions between superfluid to Mott-insulating states occur, on top of which we can have Meissner, vortex liquid, and vortex lattice phases. Also a state that explicitly breaks the symmetry between the two legs of the ladder, namely, the biased-ladder phase, is dynamically stabilized. We investigate the influence that a trapping potential has on the stability of the self-organized phases.

  17. Probing Proton Spin Structure: A Measurement of g2 at Four-momentum Transfer of 2 to 6 GeV2

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, James [Univ. of Virginia, Charlottesville, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2011-12-01

    The Spin Asymmetries of the Nucleon Experiment investigated the spin structure of the proton via inclusive electron scattering at the Continuous Electron Beam Accelerator Facility at Jefferson Laboratory in Newport News, VA. A double-polarization measurement of polarized asymmetries was performed using the University of Virginia solid polarized ammonia target with target polarization aligned longitudinal and near transverse to the electron beam, allowing the extraction of the spin asymmetries A1 and A2, and spin structure functions g1 and g2. Polarized electrons of energies of 4.7 and 5.9 GeV were scattered to be viewed by a novel, non-magnetic array of detectors observing a four-momentum transfer range of 2 to 6 GeV2. This document addresses the extraction of the spin asymmetries and spin structure functions, with a focus on spin structure function g2, which we have measured as a function of x and W in four Q2 bins.

  18. Observation of high-spin oblate band structures in Pm141

    Science.gov (United States)

    Gu, L.; Zhu, S. J.; Wang, J. G.; Yeoh, E. Y.; Xiao, Z. G.; Zhang, S. Q.; Meng, J.; Zhang, M.; Liu, Y.; Ding, H. B.; Xu, Q.; Zhu, L. H.; Wu, X. G.; He, C. Y.; Li, G. S.; Wang, L. L.; Zheng, Y.; Zhang, B.

    2011-06-01

    The high-spin states of Pm141 have been investigated through the reaction Te126(F19,4n) at a beam energy of 90 MeV. A previous level scheme has been updated with spins up to 49/2ℏ. Six collective bands at high spins are newly observed. Based on the systematic comparison, one band is proposed as a decoupled band; two bands with strong ΔI=1 M1 transitions inside the bands are suggested as the oblate bands with γ ~-60°; three other bands with large signature splitting have been proposed with the oblate-triaxial deformation with γ~ -90°. The triaxial n-particle-n-hole particle rotor model calculations for one of the oblate bands in Pm141 are in good agreement with the experimental data. The other characteristics for these bands have been discussed.

  19. Spin-dependent hot electron transport and nano-scale magnetic imaging of metal/Si structures

    International Nuclear Information System (INIS)

    Kaidatzis, A.

    2008-10-01

    In this work, we experimentally study spin-dependent hot electron transport through metallic multilayers (ML), containing single magnetic layers or 'spin-valve' (SV) tri layers. For this purpose, we have set up a ballistic electron emission microscope (BEEM), a three terminal extension of scanning tunnelling microscopy on metal/semiconductor structures. The implementation of the BEEM requirements into the sample fabrication is described in detail. Using BEEM, the hot electron transmission through the ML's was systematically measured in the energy range 1-2 eV above the Fermi level. By varying the magnetic layer thickness, the spin-dependent hot electron attenuation lengths were deduced. For the materials studied (Co and NiFe), they were compared to calculations and other determinations in the literature. For sub-monolayer thickness, a non uniform morphology was observed, with large transmission variations over sub-nano-metric distances. This effect is not yet fully understood. In the imaging mode, the magnetic configurations of SV's were studied under field, focusing on 360 degrees domain walls in Co layers. The effects of the applied field intensity and direction on the DW structure were studied. The results were compared quantitatively to micro-magnetic calculations, with an excellent agreement. From this, it can be shown that the BEEM magnetic resolution is better than 50 nm. (author)

  20. Exploring the Structure of a DNA Hairpin with the Help of NMR Spin-Spin Coupling Constants: An Experimental and Quantum Chemical Investigation

    Czech Academy of Sciences Publication Activity Database

    Sychrovský, Vladimír; Vacek, Jaroslav; Hobza, Pavel; Žídek, L.; Sklenář, V.; Cremer, D.

    2002-01-01

    Roč. 106, - (2002), s. 10242-10250 ISSN 1089-5639 R&D Projects: GA MŠk LN00A032 Institutional research plan: CEZ:AV0Z4040901 Keywords : DNA * help of NMR spin-spin coupling constants * quantum chemical investigation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.765, year: 2002

  1. Nucleon partonic spin structure to be explored by the unpolarized Drell-Yan program of COMPASS experiment at CERN

    CERN Document Server

    Chang, Wen-Chen

    2016-01-01

    The observation of the violation of Lam-Tung relation in the $\\pi N$ Drell-Yan process triggered many theoretical speculations. The TMD Boer-Mulders functions characterizing the correlation of transverse momentum and transverse spin for partons in unpolarized hadrons could nicely account for the violation. The COMPASS experiment at CERN will measure the angular distributions of dimuons from the unpolarized Drell-Yan process over a wide kinematic region and study the beam particle dependence. Significant statistics is expected from a successful run in 2015 which will bring further understanding of the origin of the violation of Lam-Tung relation and of the partonic transverse spin structure of the nucleon.

  2. Dynamical pairwise entanglement and two-point correlations in the three-ligand spin-star structure

    Science.gov (United States)

    Motamedifar, M.

    2017-10-01

    We consider the three-ligand spin-star structure through homogeneous Heisenberg interactions (XXX-3LSSS) in the framework of dynamical pairwise entanglement. It is shown that the time evolution of the central qubit ;one-particle; state (COPS) brings about the generation of quantum W states at periodical time instants. On the contrary, W states cannot be generated from the time evolution of a ligand ;one-particle; state (LOPS). We also investigate the dynamical behavior of two-point quantum correlations as well as the expectation values of the different spin-components for each element in the XXX-3LSSS. It is found that when a W state is generated, the same value of the concurrence between any two arbitrary qubits arises from the xx and yy two-point quantum correlations. On the opposite, zz quantum correlation between any two qubits vanishes at these time instants.

  3. Spin-dependent tunneling conductance in 2D structures in zero magnetic field

    International Nuclear Information System (INIS)

    Rozhansky, I.V.; Averkiev, N.S.

    2009-01-01

    The influence of the spin-orbit interaction on the tunneling between two-dimensional electron layers is considered. A general expression for the tunneling current is obtained with the Rashba and Dresselhaus effects and also elastic scattering of charge carriers on impurities taken into account. It is shown that the particular form of the tunneling conductance as a function of the voltage between layers is extremely sensitive to the relationship between the Rashba and Dresselhaus parameters. This makes it possible to determine the parameters of the spin-orbit interaction and the quantum scattering time directly from measurements of the tunneling conductance in the absence of magnetic field

  4. Atom and Amine Adsorption on Flat and Stepped Gold Surfaces & Structure, Stability and Spin Ordering in Manganese Sulfide Clusters

    Science.gov (United States)

    Lewoczko, April D.

    In part I, we investigate gold catalysis in the chemistry of organonitrogen compounds. We examine the adsorption of oxygen, nitrogen and sulfur atoms on the gold (111), (100) and (211) surfaces using density functional theory (DFT). Sulfur atoms bind most strongly, followed by oxygen and nitrogen atoms with stronger adsorption for greater coordination to the surface. We see a trend of stronger adsorption to undercoordinated gold, but find it is non-universal with the adsorption strength trend: (111) > (211) > (100). We consider the diffusion of oxygen, nitrogen and sulfur adatoms and find facile long-range diffusion of oxygen atoms on the (100) surface. Lastly, we compare the adsorption of methylamine on gold to that of a selection of alkylamines, methanol and methanethiol. In each case, the ontop site is preferred with stronger adsorption at low coordinated gold. At oxygen atom coverages of 0.125 -- 0.25 ML on Au (111), we find cooperative adsorption of methylamine and oxygen atoms. Energetic costs for adsorbate tilt from the surface normal and rotation about the gold-nitrogen bond are calculated. While methylamine rotation is barrierless on the (111) and (211) surfaces, it has a low energetic barrier for the 0.125 ML and 0.25 ML O atom pre-covered Au (111) surfaces. In part II, we interpret the experimental mass spectrum of small gas phase manganese sulfide clusters using DFT and elucidate the role of ionicity and spin ordering in sizes with special stability, i.e. magic clusters. We first consider nine low lying minima (MnS)6 structures and reveal antiferromagnetic (AFM) spin ordering with a ˜0.1 eV/pair AFM energy benefit and a ˜0.1 A shrinkage of average Mn-Mn distances over clusters with ferromagnetic (FM) spin ordering. We calculate energetic barriers for interconversion between the two lowest lying (MnS)6 isomers and predict an elevated cluster melting temperature due to increased configurational entropy in a pre-melted state. Second, we demonstrate the

  5. Structures and stabilities of group 17 fluorides EF3 (E = I, At, and element 117) with spin-orbit coupling.

    Science.gov (United States)

    Yang, Dong-Dong; Wang, Fan

    2012-12-05

    In this work, a recently developed CCSD(T) approach with spin-orbit coupling (SOC) as well as density functional theory (DFT) using various exchange-correlation (XC) functionals are employed to investigate structures and stabilities of group 17 fluorides EF(3) (E = I, At, and element 117). These molecules are predicted to have bent T-shaped C(2v) structures according to the second-order Jahn-Teller (SOJT) effects or the valance shell electron pair repulsion (VSEPR) theory. For IF(3) and (117)F(3), our results are consistent with previous SOC-DFT calculations. However, different XC functionals provide different results for AtF(3) and our SOC-CCSD(T) calculations show that both the C(2v) and D(3h) structures are minima on the potential energy surface and the C(2v) structure is the global minimum for AtF(3). The performance of XC functionals on structures and stabilities of IF(3) and AtF(3) is found to depend on the fraction of the Hartree-Fock exchange (HFX) included in the XC functionals and the M06-2X functional with 54% of HFX providing results that agree best with CCSD(T) results. In addition, although both the C(2v) and D(3h) structures are minima for AtF(3), the energy barrier between them is only 8 kJ mol(-1) for the C(2v) structure and 0.05 kJ mol(-1) for the D(3h) structure. This indicates that the D(3h) structure could not possibly be observed experimentally and AtF(3) can convert easily between the three C(2v) structures. The SOJT term is shown to be reduced by electron correlation for IF(3) and AtF(3). On the other hand, although SOC decreases the energy difference between the C(2v) and D(3h) structures and reduces the deviation of the C(2v) structure from the D(3h) structure, it decreases the frequency of the bond bending mode, which may indicate that SOC actually increases the SOJT term. This could be related to mixing of spin-singlet E' states to low-energy spin-triplet states due to SOC.

  6. Spin physics in semiconductors

    CERN Document Server

    2017-01-01

    This book offers an extensive introduction to the extremely rich and intriguing field of spin-related phenomena in semiconductors. In this second edition, all chapters have been updated to include the latest experimental and theoretical research. Furthermore, it covers the entire field: bulk semiconductors, two-dimensional semiconductor structures, quantum dots, optical and electric effects, spin-related effects, electron-nuclei spin interactions, Spin Hall effect, spin torques, etc. Thanks to its self-contained style, the book is ideally suited for graduate students and researchers new to the field.

  7. Construction and characterization of a spin polarized helium ion beam for surface electronic structure studies

    International Nuclear Information System (INIS)

    Harrison, A.R.

    1982-01-01

    Ion neutralization and metastable de-excitation spectroscopy, INS and MDS, allow detailed analysis of the surface electronic configuration of metals. The orthodox application of these spectroscopies may be enhanced by electronic spin polarization of the probe beams. For this reason, a spin polarized helium ion beam has been constructed. The electronic spin of helium metastables created within an rf discharge may be spacially aligned by optically pumping the atoms. Subsequent collisions between metastables produce helium ions which retain the orientation of the electronic spin. Extracted ion polarization, although not directly measurable, may be estimated from extracted electron polarization, metastable polarization, pumping radiation absorption and current modulation measurements. Ions extracted from the optically pumped discharge exhibit an estimated polarization of about ten per cent at a beam current of a few tenths of a microampere. Extraction of helium ions from the discharge requires that the ions have a high kinetic energy. However, to avoid undesirable kinetic electron ejection from the target surface, the ions must be decelerated. Examination of various deceleration configurations, in paticular exponential and linear deceleration fields, and experimental observation indicate that a linear decelerating field produces the best low energy beam to the target surface

  8. Fiber structure formation in melt spinning of bio-based aliphatic co-polyesters

    Science.gov (United States)

    Qin, Qing; Takarada, Wataru; Kikutani, Takeshi

    2015-05-01

    High-speed melt spinning of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) with the 3-hydroxyhexanoate composition of 5.4 mol% was carried out. Melting temperature of this polymer is 141.5°C. It has been reported that PHBH fibers of good appearance can be prepared through the melt spinning process only when extrusion temperature is lower than the melting temperature of pure PHB (176 °C). The high-speed melt spinning experiment in this study revealed that the crystallization of PHBH proceeded at high take-up velocities even when the extrusion temperature was higher than the melting temperature of PHB. This result is considered to be due to the enhancement of crystallization through the application of high tensile stress to the molten polymer in the spinning line. As-spun fibers showed sufficiently high mechanical properties. On the other hand, crystalline orientation of α-form crystal increased with an increase in the take-up velocity and the existence of a small amount of β-form crystals was detected at high take-up velocities. This is another indication for the occurrence of crystallization under high tensile stress.

  9. Correlations between atomic structure and giant magnetoresistance ratio in Co2(Fe,Mn)Si spin valves

    International Nuclear Information System (INIS)

    Lari, L; Sizeland, J; Gilks, D; Uddin, G M; Nedelkoski, Z; Hasnip, P J; Lazarov, V K; Yoshida, K; Galindo, P L; Sato, J; Oogane, M; Ando, Y; Hirohata, A

    2014-01-01

    We show that the magnetoresistance of Co 2 Fe x Mn 1−x Si-based spin valves, over 70% at low temperature, is directly related to the structural ordering in the electrodes and at the electrodes/spacer (Co 2 Fe x Mn 1−x Si/Ag) interfaces. Aberration-corrected atomic resolution Z-contrast scanning transmission electron microscopy of device structures reveals that annealing at 350 °C and 500 °C creates partial B2/L2 1 and fully L2 1 ordering of electrodes, respectively. Interface structural studies show that the Ag/Co 2 Fe x Mn 1−x Si interface is more ordered compared to the Co 2 Fe x Mn 1−x Si/Ag interface. The release of interface strain is mediated by misfit dislocations that localize the strain around the dislocation cores, and the effect of this strain is assessed by first principles electronic structure calculations. This study suggests that by improving the atomic ordering and strain at the interfaces, further enhancement of the magnetoresistance of CFMS-based current-perpendicular-to-plane spin valves is possible. (fast track communication)

  10. PT-symmetric ladders with a scattering core

    Energy Technology Data Exchange (ETDEWEB)

    D' Ambroise, J. [Department of Mathematics, Amherst College, Amherst, MA 01002-5000 (United States); Lepri, S. [CNR – Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del piano 10, I-50019 Sesto Fiorentino (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Malomed, B.A. [Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Kevrekidis, P.G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003-9305 (United States)

    2014-08-01

    We consider a PT-symmetric chain (ladder-shaped) system governed by the discrete nonlinear Schrödinger equation where the cubic nonlinearity is carried solely by two central “rungs” of the ladder. Two branches of scattering solutions for incident plane waves are found. We systematically construct these solutions, analyze their stability, and discuss non-reciprocity of the transmission associated with them. To relate the results to finite-size wavepacket dynamics, we also perform direct simulations of the evolution of the wavepackets, which confirm that the transmission is indeed asymmetric in this nonlinear system with the mutually balanced gain and loss. - Highlights: • We model a PT-symmetric ladder system with cubic nonlinearity on two central rungs. • We examine non-reciprocity and stability of incident plane waves. • Simulations of wavepackets confirm our results.

  11. Structure, magnetization, and NMR studies of the spin-glass compound (LixV1-x)3BO5 ( x≈0.40 and 0.33)

    Science.gov (United States)

    Zong, X.; Niazi, A.; Borsa, F.; Ma, X.; Johnston, D. C.

    2007-08-01

    Structural and magnetic properties of (LixV1-x)3BO5 powders (x=0.33) and single crystals (x=0.40) were studied by x-ray diffraction, magnetization, and NMR measurements. Both powder and single crystal x-ray diffraction data are consistent with the previously reported structure of the system. Magnetization measurements show an overall antiferromagnetic interaction among vanadium spins and reveal a transition into a spin glass state at a sample and magnetic field dependent temperature below ˜10K . The high temperature (T>20K) susceptibility is analyzed using a linear spin trimer model suggested in the literature but such a model is found to be insufficient to explain the data. Li7 and B11 NMR studies indicate an inhomogeneous dynamics close to the zero-field spin-glass transition temperature. The distribution of electronic spin relaxation times is derived using a recently proposed method and the broad temperature-dependent distribution obtained gives a consistent description of the NMR results. The temperature dependence of the distribution indicates a strong slowing down of the local moment spin dynamics as the system cools toward the zero-field spin-glass transition temperature even in the presence of a strong applied magnetic field up to 4.7T .

  12. The role of mesoscopic structuring on the intermixing of spin-polarised conduction channels in thin-film ferromagnets for spintronics

    Science.gov (United States)

    Alcer, D.; Atkinson, D.

    2017-09-01

    The separation of spin-up and spin-down conduction channels is fundamental to electronic transport in ferromagnets and essential for spintronic functionality. The spin states available for conduction are defined by the ferromagnetic material, but additional physical factors can affect scattering and modify the spin-dependence of conduction. Here the effect of mesoscopic structuring, arising during the growth of ferromagnetic thin films, on the electronic transport was investigated. Resistivity and anisotropic magnetoresistance were measured in a series of Ni80Fe20 thin films as a function of nominal film thickness from 3 {nm} up to 20 {nm}. The observed thickness dependence of the resisivity and magnetic anisotropy of resistivity are interpreted using a model that accounts for the macroscopic structuring from the growth of the films and incorporates a structural dependence of the spin-flip scattering. The model shows good agreement for both the thickness dependence of the resistivity and the reduction of the anisotropic magnetoresistivity. The latter indicating that increasing mixing of the conducting spin channels occurs in ultra-thin films, mainly a consequence of macroscopic structuring of the films.

  13. DUNDRUM Restriction-Intrusion of Liberty Ladders (DRILL) Audit Toolkit

    LENUS (Irish Health Repository)

    Kennedy, Harry G

    2011-09-01

    This series of rating \\'ladders\\' is intended to allow a quantitative and qualitative analysis of the use of restrictive and intrusive interventions as part of the therapeutic management of violence and aggression in psychiatric hospital settings. This is an evolving handbook. The ladders are currently organised to facilitate a behavioural analysis. Context, antecedents, behaviour, interventions, consequences are conceptualised as a series of events organised in temporal sequence so that causes, interactions and effects can be considered. The complexity of analysis possible is limited by the statistical power of the numbers of cases and events available. \\r\

  14. Command and Control Career Ladder, AFSC 274X0.

    Science.gov (United States)

    1987-04-01

    I COMMAND AND CONTROL CAREER LADDER AFSC 274X0 AFPT 90-274-774 APRIL 1987 OCCUPATIONAL ANALYSIS PROGRAM USAF OCCUPATIONAL MEASUREMENT CENTER AIR...3 HQ TAC/TTGT 1 1 HQ USAF/XODRF 1 1 HQ USAF/ MPPT 1 1 HQ USAFE/DPAT 3 3 HQ USAFE/TTGT 1 1 HO USMC (CODE TPI) 1 NODAC 1 3300 TCHTW/TTGX (KEESLER AFB MS...Command and Control career ladder (AFSC 274X0). This survey was requested by the Training Development Services Division of the USAF Occupa- tional

  15. Data structure techniques for the graphical special unitary group approach to arbitrary spin representations

    International Nuclear Information System (INIS)

    Kent, R.D.; Schlesinger, M.

    1987-01-01

    For the purpose of computing matrix elements of quantum mechanical operators in complex N-particle systems it is necessary that as much of each irreducible representation be stored in high-speed memory as possible in order to achieve the highest possible rate of computations. A graph theoretic approach to the representation of N-particle systems involving arbitrary single-particle spin is presented. The method involves a generalization of a technique employed by Shavitt in developing the graphical group approach (GUGA) to electronic spin-orbitals. The methods implemented in GENDRT and DRTDIM overcome many deficiencies inherent in other approaches, particularly with respect to utilization of memory resources, computational efficiency in the recognition and evaluation of non-zero matrix elements of certain group theoretic operators and complete labelling of all the basis states of the permutation symmetry (S N ) adapted irreducible representations of SU(n) groups. (orig.)

  16. Observation of Octupole Structures in Radon and Radium Isotopes and Their Contrasting Behavior at High Spin

    International Nuclear Information System (INIS)

    Cocks, J.; Butler, P.; Cann, K.; Greenlees, P.; Jones, G.; Asztalos, S.; Clark, R.; Deleplanque, M.; Diamond, R.; Fallon, P.; Lee, I.; Macchiavelli, A.; MacLeod, R.; Stephens, F.; Bhattacharyya, P.; Zhang, C.; Broda, R.; Fornal, B.; Jones, P.; Julin, R.; Lauritsen, T.; Smith, J.

    1997-01-01

    Multinucleon transfer reactions have been used, for the first time, to populate high-spin bands of alternating parity states in 218,220,222 Rn and 222,224,226 Ra. The behavior of the angular momentum alignment with rotational frequency for the Rn isotopes is very different when compared with Ra and Th isotopes with N∼134, indicating a transition from octupole vibrational to stable octupole deformation. Throughout the measured spin range the values of |D 0 /Q 0 | remain constant for 222 Ra and 226 Ra and have a very small value for 224 Ra, suggesting that the charge and mass distributions are not affected appreciably by rotations. copyright 1997 The American Physical Society

  17. Sodium layer chiral distribution and spin structure of Na$_2$Ni$_2$TeO$_6$ with a honeycomb network

    OpenAIRE

    Karna, Sunil K.; Zhao, Y.; Sankar, R.; Avdeev, M.; Tseng, P. C.; Wang, C. W.; Shu, G. J.; Matan, K.; Guo, G. Y.; Chou, F. C.

    2017-01-01

    The nature of Na ion distribution, diffusion path, and the spin structure of $P2$-type Na$_2$Ni$_2$TeO$_6$ with a Ni honeycomb network has been explored. The nuclear density distribution of Na ions reveals a 2D chiral pattern within Na layers without breaking the original 3D crystal symmetry, which has been achieved uniquely via an inverse Fourier transform (iFT)-assisted neutron diffraction technique. The Na diffusion pathway described by the calculated iso-surface of Na ion bond valence sum...

  18. Correlated spin glass generated by structural disorder in the amorphous Dy6Fe74B20 alloy

    Science.gov (United States)

    Tejada, J.; Martinez, B.; Labarta, A.; Chudnovsky, E. M.

    1991-10-01

    Magnetic properties of the amorphous Dy-Fe-B alloy are studied in terms of the correlated-spin-glass approach of Chudnovsky et al.$-- Features predicted by the theory are clearly observed in the experiment. It is shown that the magnetization law may be presented in the form where it is determined by the dimensionless correlation function of structural disorder, C(y), only. The analysis of the magnetization curve allows one to distinguish between different models of disorder in amorphous solids. Experimental data on Dy-Fe-B are in favor of C=exp(-1/2y2).

  19. Correlated spin glass generated by structural disorder in the amorphous Dy6Fe74B20 alloy

    International Nuclear Information System (INIS)

    Tejada, J.; Martinez, B.; Labarta, A.; Chudnovsky, E.M.

    1991-01-01

    Magnetic properties of the amorphous Dy-Fe-B alloy are studied in terms of the correlated-spin-glass approach of Chudnovsky et al.$---- Features predicted by the theory are clearly observed in the experiment. It is shown that the magnetization law may be presented in the form where it is determined by the dimensionless correlation function of structural disorder, C(y), only. The analysis of the magnetization curve allows one to distinguish between different models of disorder in amorphous solids. Experimental data on Dy-Fe-B are in favor of C=exp(-1/2y 2 )

  20. A general procedure to evaluate many-body spin operator amplitudes from periodic calculations: application to cuprates

    International Nuclear Information System (INIS)

    Moreira, Iberio de P R; Calzado, Carmen J; Malrieu, Jean-Paul; Illas, Francesc

    2007-01-01

    A general procedure is presented which permits the form of an extended spin Hamiltonian to be established for a given magnetic solid and the magnitude of its terms to be evaluated from spin polarized, Hartree-Fock or density functional calculations carried out for periodic models. The computational strategy makes use of a general mapping between the energy of pertinent broken-symmetry solutions and the diagonal terms of the spin Hamiltonian in a local representation. From this mapping it is possible to determine not only the amplitude of the well-known two-body magnetic coupling constants between near-neighbor sites, but also the amplitudes of four-body cyclic exchange terms. A scrutiny of the on-site spin densities provides additional information and control of the many broken-symmetry solutions which can be found. The procedure is applied to the La 2 CuO 4 , Sr 2 CuO 2 F 2 , Sr 2 CuO 2 Cl 2 and Ca 2 CuO 2 Cl 2 square lattices and the SrCu 2 O 3 ladder compound. It is shown that a proper description of the magnetic structure of these compounds requires that two- and four-body terms are explicitly included in the spin Hamiltonian. The implications for the interpretation of recent experiments are discussed

  1. Structural anomalies, spin transitions and charge disproportionation in LnCoO.sub.3./sub..

    Czech Academy of Sciences Publication Activity Database

    Knížek, Karel; Jirák, Zdeněk; Hejtmánek, Jiří; Henry, P.; André, G.

    2008-01-01

    Roč. 103, č. 7 (2008), 07B703/1-07B703/3 ISSN 0021-8979 R&D Projects: GA ČR GA202/06/0051 Institutional research plan: CEZ:AV0Z10100521 Keywords : LnCoO 3 * neutron diffraction * thermal expansion * spin-state transition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.201, year: 2008

  2. Room-Temperature Spin-Mediated Coupling in Hybrid Magnetic, Organic, and Oxide Structures and Devices

    Science.gov (United States)

    2015-12-07

    17013 Tianyu Liu, G. Vignale. Flexoelectric phase shifter for spin waves, Journal of Applied Physics, (04 2012): 0. doi: 10.1063/1.4703925 F. J...in magnetic materials , Nature Materials , (04 2012): 0. doi: 10.1038/nmat3311 F. Macia, P. Warnicke, D. Bedau, M.-Y. Im, P. Fischer, D.A. Arena...microspectroscopy, Journal of Magnetism and Magnetic Materials , (03 2012): 3629. doi: Nicholas J. Harmon, Michael E. Flatté. Theory of Organic

  3. Structure, magnetic ordering, and spin filtering efficiency of NiFe{sub 2}O{sub 4}(111) ultrathin films

    Energy Technology Data Exchange (ETDEWEB)

    Matzen, S.; Moussy, J.-B., E-mail: jean-baptiste.moussy@cea.fr [CEA, IRAMIS, SPCSI, F-91191 Gif-sur-Yvette (France); Wei, P. [Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Gatel, C. [CEMES-CNRS, F-31055 Toulouse (France); Cezar, J. C. [ESRF, F-38043 Grenoble (France); Arrio, M. A.; Sainctavit, Ph. [IMPMC, F-75015 Paris (France); Moodera, J. S. [Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Physics Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-05-05

    NiFe{sub 2}O{sub 4}(111) ultrathin films (3–5 nm) have been grown by oxygen-assisted molecular beam epitaxy and integrated as effective spin-filter barriers. Structural and magnetic characterizations have been performed in order to investigate the presence of defects that could limit the spin filtering efficiency. These analyses have revealed the full strain relaxation of the layers with a cationic order in agreement with the inverse spinel structure but also the presence of antiphase boundaries. A spin-polarization up to +25% has been directly measured by the Meservey-Tedrow technique in Pt(111)/NiFe{sub 2}O{sub 4}(111)/γ-Al{sub 2}O{sub 3}(111)/Al tunnel junctions. The unexpected positive sign and relatively small value of the spin-polarization are discussed, in comparison with predictions and previous indirect tunnelling magnetoresistance measurements.

  4. Measurement of the spin-dependent structure-functions of the proton and the deuteron

    CERN Multimedia

    2002-01-01

    % NA47 %title \\\\ \\\\The physics motivation of the experiments of the Spin Muon Collaboration is to better understand how the nucleon spin is built-up by its partons and to test the fundamental Bjorken sum rule. \\\\ \\\\The spin-dependent stucture functions g$ _{1} $(x) of the proton and the deuteron are determined from the measured cross section asymmetries for deep inelastic scattering of longitudinally polarized muons from longitudinally polarized nucleons. The experiment is similar to the NA2 one of the European Muon Collaboration in which the violation of the Ellis-Jaffe sum rule for the proton was found. \\\\ \\\\The apparatus is the upgraded forward spectrometer which was used originally by the European and New Muon Collaborations. To minimize the systematic uncertainties the target contains two oppositely polarized cells, which were exposed to the muon beam simultaneously. For the experiments in 1991 and 1992 the original EMC polarized target was reinstalled. In 1993 a new polarized target was put into operati...

  5. 1D and 2D assembly structures by imidazole···chloride hydrogen bonds of iron(II) complexes [Fe(II)(HL(n-Pr))3]Cl·Y (HL(n-Pr) = 2-methylimidazol-4-yl-methylideneamino-n-propyl; Y = AsF6, BF4) and their spin states.

    Science.gov (United States)

    Fujinami, Takeshi; Nishi, Koshiro; Matsumoto, Naohide; Iijima, Seiichiro; Halcrow, Malcolm A; Sunatsuki, Yukinari; Kojima, Masaaki

    2011-12-07

    Two Fe(II) complexes fac-[Fe(II)(HL(n-Pr))(3)]Cl·Y (Y = AsF(6) (1) and BF(4) (2)) were synthesized, where HL(n-Pr) is 2-methylimidazole-4-yl-methylideneamino-n-propyl. Each complex-cation has the same octahedral N(6) geometry coordinated by three bidentate ligands and assumes facial-isomerism, fac-[Fe(II)(HL(n-Pr))(3)](2+) with Δ- and Λ-enantiomorphs. Three imidazole groups per Δ- or Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) are hydrogen-bonded to three Cl(-) ions or, from the viewpoint of the Cl(-) ion, one Cl(-) ion is hydrogen-bonded to three neighbouring fac-[Fe(II)(HL(n-Pr))(3)](2+) cations. The 3 : 3 NH···Cl(-) hydrogen bonds between Δ- or Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) and Cl(-) generate two kinds of assembly structures. The directions of the 3 : 3 NH···Cl(-) hydrogen bonds and hence the resulting assembly structures are determined by the size of the anion Y, though Y is not involved into the network structure and just accommodated in the cavity. Compound 1 has a 1D ladder structure giving a larger cavity, in which the Δ- and Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) enantiomorphs are bridged by two NH···Cl(-) hydrogen bonds. Compound 2 has a 2D network structure with a net unit of a cyclic trimer of {fac-[Fe(II)(HL(n-Pr))(3)](2+)···Cl(-)}(3) giving a smaller cavity, in which Δ- or Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) species with the same chirality are linked by NH···Cl(-) hydrogen bonds to give a homochiral 2D network structure. Magnetic susceptibility and Mössbauer spectral measurements demonstrated that compound 1 showed an abrupt one-step spin crossover with 4.0 K thermal hysteresis of T(c↓) = 125.5 K and T(c↑) = 129.5 K and compound 2 showed no spin transition and stayed in the high-spin state over the 5-300 K temperature range.

  6. Longitudinal double-spin asymmetry $A_1^{\\rm p}$ and spin dependent structure function $g_1^{\\rm p}$ of the proton at small values of $x$ and $Q^2$

    CERN Document Server

    Aghasyan, M.; The COMPASS collaboration; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anfimov, N.V.; Anosov, V.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.D.R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Bressan, A.; Büchele, M.; Burtsev, V.E.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chumakov, A.G.; Chung, S.-U.; Cicuttin, A.; Crespo, M.L.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Dreisbach, Ch.; Dünnweber, W.; Dusaev, R.R.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Faessler, M.; Ferrero, A.; Finger, M.; jr.,M.Finger; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J.M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giarra, J.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grasso, A.; Gridin, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F.H.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Iwata, T.; Jary, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.M.; Kral, Z.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z.V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Kuznetsov, I.I.; Kveton, A.; Lednev, A.A.; Levchenko, E.A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Lyubovitskij, V.E.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Mamon, S.A.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.V.; Meyer, M.; Meyer, W.; Mikhailov, Yu.V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Moretti, A.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Pešková, M.; Peshekhonov, D.V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rogacheva, N.S.; Ryabchikov, D.I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V.D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I.A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thiel, A.; Tomsa, J.; Tosello, F.; Tskhay, V.; Uhl, S.; Vasilishin, B.I.; Vauth, A.; Veloso, J.; Vidon, A.; Virius, M.; Wallner, S.; Weisrock, T.; Wilfert, M.; ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.

    2017-01-01

    We present a precise measurement of the proton longitudinal double-spin asymmetry $A_1^{\\rm p}$ and the proton spin-dependent structure function $g_1^{\\rm p}$ at photon virtualities $0.006~({\\rm GeV}/c)^2< Q^2< 1~ ({\\rm GeV}/c)^2$ in the Bjorken $x$ range of $4 \\times 10^{-5} < x < 4 \\times 10^{-2}$. The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of $160~{\\rm GeV}$ and $200~ {\\rm GeV}$. The statistical precision is more than tenfold better than that of the previous measurement in this region. In the whole range of $x$, the measured values of $A_1^{\\rm p}$ and $g_1^{\\rm p}$ are found to be positive. It is for the first time that spin effects are found at such low values of $x$.

  7. Spin-polarized transport in manganite-based magnetic nano structures

    International Nuclear Information System (INIS)

    Granada, Mara

    2007-01-01

    Giant magnetoresistance (G M R) and tunnel magnetoresistance are spin polarized transport phenomena which are observed in magnetic multilayers.They consist in a large variation of the electrical resistivity of the system depending on whether the magnetizations of the magnetic layers are aligned parallel or anti-parallel to each other. In order to be able to align the magnetic layers by means of an external magnetic field, they must not be strongly ferromagnetically coupled.The extrinsic magnetoresistance effects in magnetic multilayers, either G M R in the case of a metallic spacer, or T M R in the case of an insulating spacer, are observed at low magnetic fields, which makes these phenomena interesting for technological applications.We studied the possibility of using the ferromagnetic manganite La 0 ,75Sr 0 ,25MnO 3 (L S M O) in magneto resistive devices, with different materials as a spacer layer.As the main result of this work, we report G M R and T M R measurements in L S M O/LaNiO 3 /L S M O and L S M O/CaMnO 3 /L S M O tri layers, respectively, observed for the first time in these systems.This work included the deposition of films and multilayers by sputtering, the structural characterization of the samples and the study of their magnetic and electric transport properties.Our main interest was the study of G M R in L S M O/LaNiO 3 /L S M O tri layers.It was necessary to firstly characterize the magnetic coupling of L S M O layers through the L N O spacer. After that, we performed electric transport measurements with the current in the plane of the samples.We measured a G M R contribution of ∼ 0,55 % at T = 83 K.We designed a procedure for patterning the samples by e-beam lithography for electric transport measurements with the current perpendicular to the plane. We also performed the study of L S M O/CaMnO 3 /L S M O tri layers with an insulating spacer.We studied the magnetic coupling, as in the previous case.Then we fabricated a tunnel junction for

  8. Phase dynamics of a Josephson junction ladder driven by modulated currents

    International Nuclear Information System (INIS)

    Kawaguchi, T.

    2011-01-01

    Phase dynamics of disordered Josephson junction ladders (JJLs) driven by external currents which are spatially and temporally modulated is studied using a numerical simulation based on a random field XY model. This model is considered theoretically as an effective model of JJLs with structural disorder in a magnetic field. The spatiotemporal modulation of external currents causes peculiar dynamical effects of phases in the system under certain conditions, such as the directed motion of phases and the mode-locking in the absence of dc currents. We clarify the details of effects of the spatiotemporal modulation on the phase dynamics.

  9. Asparagine and glutamine ladders promote cross-species prion conversion.

    Science.gov (United States)

    Kurt, Timothy D; Aguilar-Calvo, Patricia; Jiang, Lin; Rodriguez, José A; Alderson, Nazilla; Eisenberg, David S; Sigurdson, Christina J

    2017-11-17

    Prion transmission between species is governed in part by primary sequence similarity between the infectious prion aggregate, PrP Sc , and the cellular prion protein of the host, PrP C A puzzling feature of prion formation is that certain PrP C sequences, such as that of bank vole, can be converted by a remarkably broad array of different mammalian prions, whereas others, such as rabbit, show robust resistance to cross-species prion conversion. To examine the structural determinants that confer susceptibility or resistance to prion conversion, we systematically tested over 40 PrP C variants of susceptible and resistant PrP C sequences in a prion conversion assay. Five key residue positions markedly impacted prion conversion, four of which were in steric zipper segments where side chains from amino acids tightly interdigitate in a dry interface. Strikingly, all five residue substitutions modulating prion conversion involved the gain or loss of an asparagine or glutamine residue. For two of the four positions, Asn and Gln residues were not interchangeable, revealing a strict requirement for either an Asn or Gln residue. Bank voles have a high number of Asn and Gln residues and a high Asn:Gln ratio. These findings suggest that a high number of Asn and Gln residues at specific positions may stabilize β-sheets and lower the energy barrier for cross-species prion transmission, potentially because of hydrogen bond networks from side chain amides forming extended Asn/Gln ladders. These data also suggest that multiple PrP C segments containing Asn/Gln residues may act in concert along a replicative interface to promote prion conversion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Predictors of Outcomes in a Performance Ladder Program.

    Science.gov (United States)

    Dicks, Robert H.; McHenry, James D.

    1985-01-01

    Investigated variables from initial inmate evaluations at a state penitentiary as predictors of inmate success in behavioral ladder program. Results indicated that academic test variables were best predictors of overall success level, attitudes, and work habits. Personality variables and one interview observation variable were also found to be…

  11. A robustification of the chain-ladder method

    NARCIS (Netherlands)

    Verdonck, T.; van Wouwe, M.; Dhaene, J.

    2009-01-01

    In a non-life insurance business an insurer often needs to build up a reserve to able to meet his or her future obligations arising from incurred but not reported completely claims. To forecast these claims reserves, a simple but generally accepted algorithm is the classical chain-ladder method.

  12. Workload of window cleaners using ladders differing in rung separation

    NARCIS (Netherlands)

    Hoozemans, M.J.M.; Looze, M.P. de; Kingma, I.; Reijneveld, K.C.N.; Korte, E.M. de; Grinten, M.P. van der; Dieën, J.H. van

    2005-01-01

    The objective of the present study was to compare energetic workload, perceived exertion, perceived discomfort, safety, and mechanical load at lower limb joints among window cleaners during usage of extension ladders with 30 and 35 cm rung separation. Eleven healthy male professional window cleaners

  13. Dynamic parameterization and ladder operators for the Kratzer molecular potential

    International Nuclear Information System (INIS)

    Devi, O Babynanda; Singh, C Amuba

    2014-01-01

    Introducing independent parameters k and δ to represent the strength of the attractive and repulsive components, respectively, we write the Kratzer molecular potential as V(k,δ)=(ℏ 2 /2 m)(−k/r+δ(δ−1)/r 2 ). This parameterisation is not only natural, but also convenient for the construction of ladder operators for the system. Adopting the straightforward method of deriving recurrence relations among confluent hypergeometric functions, we construct seven pairs of ladder operators for the Kratzer potential system. Detailed analysis of the laddering actions of these operators is given to show that they connect eigenstates of equal energy but belong to a hierarchy of Kratzer potential systems corresponding to different values of the parameters k and δ. Significantly, it is pointed out that it may not be possible to construct, in the position representation, a ladder operator which would connect different eigenstates belonging to the same potential V(k,δ). Transition to the hydrogen atom case is discussed. A number (14 altogether) of functional relations among the confluent hypergeometric functions have been derived and reported separately in an appendix. (paper)

  14. Towards flavored bound states beyond rainbows and ladders

    International Nuclear Information System (INIS)

    El-Bennich, B.; Rojas, E.; Melo, J. P. B. C. de; Paracha, M. A.

    2014-01-01

    We give a snapshot of recent progress in solving the Dyson-Schwinger equation with a beyond rainbow-ladder ansatz for the dressed quark-gluon vertex which includes ghost contributions. We discuss the motivations for this approach with regard to heavy-flavored bound states and form factors and briefly describe future steps to be taken

  15. Education for Sustainability: A Snakes and Ladders Game?

    Directory of Open Access Journals (Sweden)

    Daniella Tilbury

    2015-07-01

    Full Text Available How to reference this articleTilbury, D. (2015. Education for Sustainability: A Snakes and Ladders Game?. Foro de Educación, 13(19, 7-10. doi: http://dx.doi.org/10.14516/fde.2015.013.019.000

  16. Deep inelastic scattering of polarized electrons by polarized 3 He and the study of the neutron spin structure

    International Nuclear Information System (INIS)

    Arnold, R.G.; Bosted, P.E.; Dunne, J.; Fellbaum, J.; Keppel, C.; Rock, S.E.; Spengos, M.; Szalata, Z.M.; White, J.L.; Breton, V.; Fonvieille, H.; Roblin, Y.; Shapiro, G.; Hughes, E.W.; Borel, H.; Lombard-Nelsen, R.M.; Marroncle, J.; Morgenstern, J.; Staley, F.; Terrien, Y.; Anthony, P.L.; Dietrich, F.S.; Chupp, T.E.; Smith, T.; Thompson, A.K.; Kuhn, S.E.; Cates, G.D.; Middleton, H.; Newbury, N.R.; Anthony, P.L.; Gearhart, R.; Hughes, E.W.; Maruyama, T.; Meyer, W.; Petratos, G.G.; Pitthan, R.; Rokni, S.H.; Stuart, L.M.; White, J.L.; Woods, M.; Young, C.C.; Erbacher, R.; Kawall, D.; Kuhn, S.E.; Meziani, Z.E.; Holmes, R.; Souder, P.A.; Xu, J.; Meziani, Z.E.; Band, H.R.; Johnson, J.R.; Maruyama, T.; Prepost, R.; Zapala, G.

    1996-01-01

    The neutron longitudinal and transverse asymmetries A 1 n and A 2 n have been extracted from deep inelastic scattering of polarized electrons by a polarized 3 He target at incident energies of 19.42, 22.66 and 25.51 GeV. The measurement allows for the determination of the neutron spin structure functions g 1 n (x, Q 2 ) and g 2 n (x, Q 2 ) over the range 0.03 2 of 2 (GeV/c) 2 . The data are used for the evaluation of the Ellis-Jaffe and Bjorken sum rules. The neutron spin structure function g 1 n (x, Q 2 ) is small and negative within the range of our measurement, yielding an integral ∫ 0.03 0.6 g 1 n (x)dx - 0.028 ± 0.006 (stat) ± 0.006 (syst). Assuming Regge behavior at low x, we extract Γ 1 n ∫ 0 1 g 1 n (x)dx = - 0.031 ± 0.006 (stat) ± 0.009 (syst). Combined with previous proton integral results from SLAC experiment E143, we find Γ 1 p - Γ 1 n = 0.160 ± 0.015 in agreement with the Bjorken sum rule prediction Γ 1 p - Γ 1 p 0.176 ± 0.008 at a Q 2 value of 3 (GeV/c) 2 evaluated using α s 0.32 ± 0.05. (authors)

  17. Analytic expression of the temperature increment in a spin transfer torque nanopillar structure

    International Nuclear Information System (INIS)

    You, Chun-Yeol; Ha, Seung-Seok; Lee, Hyun-Woo

    2009-01-01

    The temperature increment due to the Joule heating in a nanopillar spin transfer torque system is investigated. We obtain a time-dependent analytic solution of the heat conduction equation in nanopillar geometry by using the Green's function method after some simplifications of the problem. While Holm's equation is applicable only to steady states in metallic systems, our solution describes the time dependence and is also applicable to a nanopillar-shaped magnetic tunneling junction with an insulator barrier layer. The validity of the analytic solution is confirmed by numerical finite element method simulations and by the comparison with Holm's equation.

  18. Quantum teleportation and entanglement swapping of electron spins in superconducting hybrid structures

    Energy Technology Data Exchange (ETDEWEB)

    Bubanja, Vladimir, E-mail: vladimir.bubanja@callaghaninnovation.govt.nz

    2015-06-15

    We present schemes for quantum teleportation and entanglement swapping of electronic spin states in hybrid superconductor–normal-metal systems. The proposed schemes employ subgap transport whereby the lowest order processes involve Cooper pair-electron and double Cooper-pair cotunneling in quantum teleportation and entanglement swapping protocols, respectively. The competition between elastic cotunneling and Cooper-pair splitting results in the success probability of 25% in both cases. Described implementations of these protocols are within reach of present-day experimental techniques.

  19. Falls from ladders: age matters more than height.

    Science.gov (United States)

    Con, Jorge; Friese, Randall S; Long, Dustin M; Zangbar, Bardiya; O'Keeffe, Terence; Joseph, Bellal; Rhee, Peter; Tang, Andrew L

    2014-10-01

    Falls from ladders account for a significant number of hospital visits. However, the epidemiology, injury pattern, and how age affects such falls are poorly described in the literature. Patients ≥18 y who suffered falls from ladders over a 5½-y period were identified in our trauma registry. Dividing patients into three age groups (18-45, 46-65, and >66 y), we compared demographic characteristics, clinical data, and outcomes including injury pattern and mortality. The odds ratios (ORs) were calculated with the group 18-45 y as reference; group means were compared with one-way analysis of variance. Of 27,155 trauma patients, 340 (1.3%) had suffered falls from ladders. The average age was 55 y, with a male predominance of 89.3%. Average fall height was 9.8 ft, and mean Injury Severity Score was 10.6. Increasing age was associated with a decrease in the mean fall height (P 66 y: OR, 5.3; confidence interval [CI], 2.5-11.5). In univariate analysis, patients in the >66-y age group were more likely to sustain traumatic brain injuries (OR, 3.4; CI, 1.5-7.8) and truncal injuries (OR, 3.6; CI, 1.9-7.0) and less likely to sustain hand and/or forearm fractures (OR, 0.3; CI, 0.1-0.9). Older people are particularly vulnerable after falling from ladders. Although they fell from lower heights, the elderly sustained different and more severe injury patterns. Ladder safety education should be particularly tailored at the elderly. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Improved resolution and simplification of the spin-diffusion-based NMR method for the structural analysis of mixed-linker MOFs

    Science.gov (United States)

    Krajnc, Andraž; Bueken, Bart; De Vos, Dirk; Mali, Gregor

    2017-06-01

    Nuclear magnetic resonance spectroscopy combined with modeling represents a powerful tool for the structural analysis of heterogeneous materials. In this contribution we describe an upgraded method, particularly suited for the structural analysis of mixed-linker metal-organic framework materials, which is based on the measurement and modeling of proton spin diffusion among constituents. We tested the method on a UiO-66-type metal-organic material, in which the organic building units were 1,4-benzenedicarboxylate and trans-1,4-cyclohexanedicarboxylate anions distributed within the framework in an unknown manner. We showed that resolution of the signals of different building units could be significantly enhanced by the carbon-detected version of the proton spin-diffusion measurement. Because this kind of measurement is much more time consuming than the proton-detected measurement and because one has to carry out several two-dimensional measurements to extract spin-diffusion curves, we inspected the possibility of reducing the number of such measurements. This could be done by limiting the analysis to short mixing times, for which, as shown in this contribution, linear approximation is valid. When working in the linear regime, only a few experimental points are needed to determine the slope of spin-diffusion curves. Usage of short spin-diffusion mixing times significantly shortened the total measurement time and also markedly simplified the modeling of spin-diffusion curves.

  1. Spin-echo small-angle neutron scattering study of the structure organization of the chromatin in biological cell

    International Nuclear Information System (INIS)

    Iashina, E G; Grigoriev, S V; Bouwman, W G; Duif, C P; Filatov, M V

    2017-01-01

    Spin-echo small-angle scattering (SESANS) technique is a method to measure the structure of materials from nano- to micrometer length scales. This method could be important for studying the packaging of DNA in the eukaryotic cell. We measured the SESANS function from chicken erythrocyte nuclei which is well fitted by the exponential function G ( z ) = exp(− z / ξ ), where ξ is the correlation length of a nucleus (in experimental data ξ = 3, 3 μ m). The exponential decay of G ( z ) corresponds to the logarithmic pair correlation function γ ( r ) = ln( ξ / r ). As the sensitivity of the SESANS signal depends on the neutron wavelength, we propose the SESANS setup with the changeable wavelength in the range from 2 to 12 Å. Such option allows one to study in great detail the internal structure of the biological cell in the length scale from 10 −2 μ m to 10 μ m. (paper)

  2. Spin-echo small-angle neutron scattering study of the structure organization of the chromatin in biological cell

    Science.gov (United States)

    Iashina, E. G.; Bouwman, W. G.; Duif, C. P.; Filatov, M. V.; Grigoriev, S. V.

    2017-06-01

    Spin-echo small-angle scattering (SESANS) technique is a method to measure the structure of materials from nano- to micrmeter length scales. This method could be important for studying the packaging of DNA in the eukaryotic cell. We measured the SESANS function from chicken erythrocyte nuclei which is well fitted by the exponential function G(z) = exp(-z/ξ), where ξ is the correlation length of a nucleus (in experimental data ξ = 3, 3 μm). The exponential decay of G(z) corresponds to the logarithmic pair correlation function γ(r) = ln(ξ/r). As the sensitivity of the SESANS signal depends on the neutron wavelength, we propose the SESANS setup with the changeable wavelength in the range from 2 to 12 Å. Such option allows one to study in great detail the internal structure of the biological cell in the length scale from 10-2 μm to 10 μm.

  3. Formation of CCP-NOL in CPP-GMR spin valve structure for the enhancement of magnetoresistance

    International Nuclear Information System (INIS)

    Kang, Y.M.; Isogami, S.; Tsunoda, M.; Takahashi, M.; Yoo, S.I.

    2007-01-01

    For the MR enhancement in current perpendicular to plane-giant magetoresistance spin valve (CPP-GMR SV), a current-confined path-nano-oxide layer (CCP-NOL)-AlO x was formed on the Cu spacer of half SV structure. In order to form effective current-confining paths, an ultra-thin AlO x layer was deposited on a Cu spacer layer by O 2 reactive sputtering of Al with infra-red (IR) heat treatment on the substrate, and that enable to form an island-structured insulating AlO x layer having holes between AlO x islands. By controlling PO 2 and substrate temperature in the NOL deposition, AlO x layer formation without an oxidizing bottom layer could be achieved

  4. Platinum/yttrium iron garnet inverted structures for spin current transport

    Energy Technology Data Exchange (ETDEWEB)

    Aldosary, Mohammed; Li, Junxue; Tang, Chi; Xu, Yadong; Shi, Jing [Department of Physics and Astronomy and SHINES Energy Frontier Research Center, University of California, Riverside, California 92521 (United States); Zheng, Jian-Guo [Irvine Materials Research Institute, University of California, Irvine, California 92697 (United States); Bozhilov, Krassimir N. [Central Facility for Advanced Microscopy and Microanalysis, University of California, Riverside, California 92521 (United States)

    2016-06-13

    30-80 nm thick yttrium iron garnet (YIG) films are grown by pulsed laser deposition on a 5 nm thick sputtered Pt atop gadolinium gallium garnet substrate (GGG) (110). Upon post-growth rapid thermal annealing, single crystal YIG(110) emerges as if it were epitaxially grown on GGG(110) despite the presence of the intermediate Pt film. The YIG surface shows atomic steps with the root-mean-square roughness of 0.12 nm on flat terraces. Both Pt/YIG and GGG/Pt interfaces are atomically sharp. The resulting YIG(110) films show clear in-plane uniaxial magnetic anisotropy with a well-defined easy axis along 〈001〉 and a peak-to-peak ferromagnetic resonance linewidth of 7.5 Oe at 9.32 GHz, similar to YIG epitaxially grown on GGG. Both spin Hall magnetoresistance and longitudinal spin Seebeck effects in the inverted bilayers indicate excellent Pt/YIG interface quality.

  5. Spin current

    CERN Document Server

    Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi

    2012-01-01

    In a new branch of physics and technology called spin-electronics or spintronics, the flow of electrical charge (usual current) as well as the flow of electron spin, the so-called 'spin current', are manipulated and controlled together. This book provides an introduction and guide to the new physics and application of spin current.

  6. Spin glasses (II)

    International Nuclear Information System (INIS)

    Fischer, K.H.

    1985-01-01

    Experimental results of spin glass studies are reviewed and related to existing theories. Investigations of spin glasses are concentrated on atomic structure, metallurgical treatment, and high-temperature susceptibility of alloys, on magnetic properties at low temperature and near the freezing temperature, on anisotropy behaviour measured by ESR, NMR and torque, on specific heat, Moessbauer effect, neutron scattering and muon-spin depolarization experiments, ultrasound and transport properties. Some new theories of spin glasses are discussed which have been developed since Part I appeared

  7. Electronic structures and spectroscopic properties of CdI: MRCI+Q study including spin-orbit coupling

    Science.gov (United States)

    Li, Rui; Zhang, Hua; Liu, Xiaohua; Zhao, Shutao; Liu, Yadong; Yan, Bing

    2018-01-01

    Cadmium iodide (CdI), which is a candidate for laser material in chemical lasing, has attracted considerable scientific interest. While the complete picture for electronic structure of CdI is still unclear, particularly for the interactions of excited states. In this paper, high-level configuration interaction method is applied to compute the low-lying electronic states of the lowest two dissociation limits (Cd(1S) + I(2P) and Cd(3P) + I(2P)). To ensure the accuracy, the Davidson correction, core-valence electronic correlations and spin-orbit coupling effects are also taken into account. The potential energy curves of the 14 Λ-S states and 30 Ω states obtained from those Λ-S states are calculated. On the basis of the computed potential energy curves, the spectroscopic constants of bound and quasibound states are determined, most of which have not been reported in existing studies. The calculated values of spin-orbit coupling matrix elements demonstrate that the B2Σ+1/2 state imposes a strong perturbation on ν‧> 0 vibrational level of C2Π1/2, which can explain the weak spectral intensity of C2Π1/2-X2Σ+1/2 observed in previous experiment. The transition dipole moments as well as the lifetimes are evaluated to predict the transition properties of B2Σ+1/2, C2Π1/2 and 22Π3/2 states.

  8. Moments of the spin structure functions g1p and g1d for 0.0522

    International Nuclear Information System (INIS)

    Prok, Y.; Bosted, P.; Burkert, V.D.; Deur, A.; Dharmawardane, K.V.; Dodge, G.E.; Griffioen, K.A.; Kuhn, S.E.; Minehart, R.; Adams, G.; Amaryan, M.J.; Anghinolfi, M.; Asryan, G.; Audit, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J.P.; Baltzell, N.A.; Barrow, S.

    2009-01-01

    The spin structure functions g 1 for the proton and the deuteron have been measured over a wide kinematic range in x and Q 2 using 1.6 and 5.7 GeV longitudinally polarized electrons incident upon polarized NH 3 and ND 3 targets at Jefferson Lab. Scattered electrons were detected in the CEBAF Large Acceptance Spectrometer, for 0.05 2 2 and W 1 for the proton and deuteron are presented - both have a negative slope at low Q 2 , as predicted by the extended Gerasimov-Drell-Hearn sum rule. The first extraction of the generalized forward spin polarizability of the proton γ 0 p is also reported. This quantity shows strong Q 2 dependence at low Q 2 . Our analysis of the Q 2 evolution of the first moment of g 1 shows agreement in leading order with Heavy Baryon Chiral Perturbation Theory. However, a significant discrepancy is observed between the γ 0 p data and Chiral Perturbation calculations for γ 0 p , even at the lowest Q 2

  9. Study of the origin of magnetic couples induced by spin-orbit coupling in Co/Pt-based asymmetrical structures

    International Nuclear Information System (INIS)

    Drouard, Marc

    2014-01-01

    In order to reduce power consumption in next generations' electronic devices, one potential solution is to implement non-volatility in memory cells. In this goal, the magnetization switching of a ferromagnetic material has been used in a memory concept: the MRAM. The latest development of this technology, called SOT-RAM, is based on new phenomena called SOTs (Spin-Orbit Torques) in order to control magnetization direction. Contrary to precedent generations (STT-MRAM), it should achieve a higher operating speed and an endurance adapted for cache and main memories applications. SOTs is a generic term referring to all the effects, linked to the spin-orbit interaction, and that enable magnetization reversal. They are yet not perfectly understood. The main objective of this Ph.D. was then to study these SOTs through a quasi-static experimental measurement setup based on anomalous and planar Hall effects. Its implementation and the associated analysis method, as well as the required theoretical considerations for data interpretation are detailed in this manuscript. It has been highlighted that magnetization switching in perpendicularly magnetization cobalt-platinum Systems cannot be explained by the simple models considered thus far in the literature. As a matter of fact it has been evidenced that at least two effects have to be considered in order to explain observed phenomena. In addition, they present different susceptibility both to a modification of the crystal structure and to a temperature change. (author) [fr

  10. The Spin-dependent Structure Function of the Proton $g_{1}^p$ and a Test of the Bjorken Sum Rule

    CERN Document Server

    Alekseev, M.G.; Alexandrov, Yu.; Alexeev, G.D.; Amoroso, A.; Austregesilo, A.; Badelek, B.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Bedfer, Y.; Bernhard, J.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.P.; Chaberny, D.; Cotic, D.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Colantoni, M.; Crespo, M.L.; Dalla Torre, S.; Das, S.; Dasgupta, S.S.; Denisov, O.Yu.; Dhara, L.; Diaz, V.; Donskov, S.V.; Doshita, N.; Duic, V.; Dunnweber, W.; Efremov, A.; El Alaoui, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger, M., Jr.; Fischer, H.; Franco, C.; Friedrich, J.M.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gazda, R.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Grabmuller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Haas, F.; von Harrach, D.; Hasegawa, T.; Heinsius, F.H.; Hermann, R.; Herrmann, F.; Hess, C.; Hinterberger, F.; Horikawa, N.; Hoppner, Ch.; d'Hose, N.; Ilgner, C.; Ishimoto, S.; Ivanov, O.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jasinski, P.; Jegou, G.; Joosten, R.; Kabuss, E.; Kafer, W.; Kang, D.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konopka, R.; Konorov, I.; Konstantinov, V.F.; Korzenev, A.; Kotzinian, A.M.; Kouznetsov, O.; Kowalik, K.; Kramer, M.; Kral, A.; Kroumchtein, Z.V.; Kuhn, R.; Kunne, F.; Kurek, K.; Lauser, L.; Le Goff, J.M.; Lednev, A.A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Liska, T.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Mann, A.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Massmann, F.; Matsuda, T.; Maximov, A.N.; Meyer, W.; Michigami, T.; Mikhailov, Yu.V.; Moinester, M.A.; Mutter, A.; Nagaytsev, A.; Nagel, T.; Nassalski, J.; Negrini, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.I.; Nunes, A.S.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pawlukiewicz-Kaminska, B.; Perevalova, E.; Pesaro, G.; Peshekhonov, D.V.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pontecorvo, G.; Pretz, J.; Quintans, C.; Rajotte, J.F.; Ramos, S.; Rapatsky, V.; Reicherz, G.; Richter, A.; Robinet, F.; Rocco, E.; Rondio, E.; Ryabchikov, D.I.; Samoylenko, V.D.; Sandacz, A.; Santos, H.; Sapozhnikov, M.G.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schmitt, L.; Schluter, T.; Schopferer, S.; Schroder, W.; Shevchenko, O.Yu.; Siebert, H.W.; Silva, L.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sosio, S.; Sozzi, F.; Srnka, A.; Stolarski, M.; Sulc, M.; Sulej, R.; Takekawa, S.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Tkatchev, L.G.; Uhl, S.; Uman, I.; Virius, M.; Vlassov, N.V.; Vossen, A.; Weitzel, Q.; Windmolders, R.; Wislicki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zhao, J.; Zhuravlev, N.; Zvyagin, A.

    2010-01-01

    The inclusive double-spin asymmetry, $A_{1}^{p}$, has been measured at COMPASS in deepinelastic polarised muon scattering off a large polarised NH3 target. The data, collected in the year 2007, cover the range Q2 > 1 (GeV/c)^2, 0.004 < x < 0.7 and improve the statistical precision of g_{1}^{p}(x) by a factor of two in the region x < 0.02. The new proton asymmetries are combined with those previously published for the deuteron to extract the non-singlet spin-dependent structure function g_1^NS(x,Q2). The isovector quark density, Delta_q_3(x,Q2), is evaluated from a NLO QCD fit of g_1^NS. The first moment of Delta_q3 is in good agreement with the value predicted by the Bjorken sum rule and corresponds to a ratio of the axial and vector coupling constants g_A/g_V = 1.28+-0.07(stat)+-0.10(syst).

  11. Gauge invariant sub-structures of tree-level double-emission exact QCD spin amplitudes

    CERN Document Server

    Van Hameren, A

    2009-01-01

    In this note we discuss possible separations of exact, massive, tree-level spin amplitudes into gauge invariant parts. We concentrate our attention on processes involving two quarks entering a color- neutral current and, thanks to the QCD interactions, two extra external gluons. We will search for forms compatible with parton shower languages, without applying approximations or restrictions on phase space regions. Special emphasis will be put on the isolation of parts necessary for the construction of evolution kernels for individual splittings and to some degree for the running coupling constant as well. Our aim is to better understand the environment necessary to optimally match hard matrix elements with partons shower algorithms. To avoid complications and ambiguities related to regularization schemes, we ignore, at this point, virtual corrections. Our representation is quite universal: any color-neutral current can be used, in particular our approach is not restricted to vector currents only.

  12. Temperature- and pressure-dependent structural study of {Fe(pmd)2[Ag(CN)2]2}n spin-crossover compound by neutron Laue diffraction.

    Science.gov (United States)

    Rodríguez-Velamazán, José Alberto; Cañadillas-Delgado, Laura; Castro, Miguel; McIntyre, Garry J; Real, José Antonio

    2014-06-01

    The effect of pressure (up to 0.17 GPa) on the spin-crossover compound {Fe(pmd)2[Ag(CN)2]2}n [orthorhombic isomer (II), pmd = pyrimidine] has been investigated by temperature- and pressure-dependent neutron Laue diffraction and magnetometry. The cooperative high-spin ↔ low-spin transition, centred at ca 180 K at ambient pressure, is shifted to higher temperatures as pressure is applied, showing a moderate sensitivity of the compound to pressure, since the spin transition is displaced by ca 140 K GPa(-1). The space-group symmetry (orthorhombic Pccn) remains unchanged over the pressure-temperature (P-T) range studied. The main structural consequence of the high-spin to low-spin transition is the contraction of the distorted octahedral [FeN6] chromophores, being more marked in the axial positions (occupied by the pmd units), than in the equatorial positions (occupied by four [Ag(CN)2](-) bridging ligands).

  13. Proximity Band Structure and Spin Textures on Both Sides of Topological-Insulator/Ferromagnetic-Metal Interface and Their Charge Transport Probes.

    Science.gov (United States)

    Marmolejo-Tejada, Juan Manuel; Dolui, Kapildeb; Lazić, Predrag; Chang, Po-Hao; Smidstrup, Søren; Stradi, Daniele; Stokbro, Kurt; Nikolić, Branislav K

    2017-09-13

    The control of recently observed spintronic effects in topological-insulator/ferromagnetic-metal (TI/FM) heterostructures is thwarted by the lack of understanding of band structure and spin textures around their interfaces. Here we combine density functional theory with Green's function techniques to obtain the spectral function at any plane passing through atoms of Bi 2 Se 3 and Co or Cu layers comprising the interface. Instead of naively assumed Dirac cone gapped by the proximity exchange field spectral function, we find that the Rashba ferromagnetic model describes the spectral function on the surface of Bi 2 Se 3 in contact with Co near the Fermi level E F 0 , where circular and snowflake-like constant energy contours coexist around which spin locks to momentum. The remnant of the Dirac cone is hybridized with evanescent wave functions from metallic layers and pushed, due to charge transfer from Co or Cu layers, a few tenths of an electron-volt below E F 0 for both Bi 2 Se 3 /Co and Bi 2 Se 3 /Cu interfaces while hosting distorted helical spin texture wounding around a single circle. These features explain recent observation of sensitivity of spin-to-charge conversion signal at TI/Cu interface to tuning of E F 0 . Crucially for spin-orbit torque in TI/FM heterostructures, few monolayers of Co adjacent to Bi 2 Se 3 host spectral functions very different from the bulk metal, as well as in-plane spin textures (despite Co magnetization being out-of-plane) due to proximity spin-orbit coupling in Co induced by Bi 2 Se 3 . We predict that out-of-plane tunneling anisotropic magnetoresistance in Cu/Bi 2 Se 3 /Co vertical heterostructure can serve as a sensitive probe of the type of spin texture residing at E F 0 .

  14. The Spin Structure of 3He and the Neutron at Low Q2: A Measurement of the Generalized GDH Integrand

    Energy Technology Data Exchange (ETDEWEB)

    Sulkosky, Vincent [College of William and Mary, Williamsburg, VA (United States)

    2007-08-01

    Since the 1980's, the study of nucleon (proton or neutron) spin structure has been an active field both experimentally and theoretically. One of the primary goals of this work is to test our understanding of Quantum Chromodynamics (QCD), the fundamental theory of the strong interaction. In the high energy region of asymptotically free quarks, QCD has been verified. However, verifiable predictions in the low energy region are harder to obtain due to the complex interactions between the nucleon's constituents: quarks and gluons. In the non-pertubative regime, low-energy effective field theories such as chiral perturbation theory provide predictions for the spin structure functions in the form of sum rules. Spin-dependent sum rules such as the Gerasimov-Drell-Hearn (GDH) sum rule are important tools available to study nucleon spin structure. Originally derived for real photon absorption, the Gerasimov-Drell-Hearn (GDH) sum rule was first extended for virtual photon absorption in 1989. The extension of the sum rule provides a unique relation, valid at any momentum transfer ($Q^{2}$), that can be used to study the nucleon spin structure and make comparisons between theoretical predictions and experimental data. Experiment E97-110 was performed at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) to examine the spin structure of the neutron and $^{3}$He. The Jefferson Lab longitudinally-polarized electron beam with incident energies between 1.1 and 4.4 GeV was scattered from a longitudinally or transversely polarized $^{3}$He gas target in the Hall A end station. Asymmetries and polarized cross-section differences were measured in the quasielastic and resonance regions to extract the spin structure functions $g_{1}(x,Q^{2})$ and $g_{2}(x,Q^{2})$ at low momentum transfers (0.02 $< Q^{2} <$ 0.3 GeV$^{2}$). The goal of the experiment was to perform a precise measurement of the $Q^{2}$ dependence of the extended GDH integral and of the moments of

  15. Selection of an experimental fish ladder located at the dam of the Itaipu Binacional, Paraná River, Brazil

    Directory of Open Access Journals (Sweden)

    Domingo Rodriguez Fernandez

    2004-08-01

    Full Text Available The specific selection of a weir and orifice type experimental fish ladder in the dam of the Itaipu Reservoir (Paraná River was evaluated by samplings in the river downstream and at two points along the ladder (at heights of 10 m and 27 m during 28 months. Among the 65 species recorded in the river (immediate downstream of the dam, 27 were captured on the ladder. The species that showed highest density on the ladder, the majority migratory, were moderately, or only slightly, abundant downstream. Among the most abundant species downstream, only one, non-migratory, was recorded in the ladder. The structure presented a negative selection in relation to large migratory pimelodids that might be overcome by enlarging the scale of its design. The sampling demonstrated a moderate selection of species along the ladder and its hydraulic model proved satisfactory regarding the attraction and efficient ascent of the fishes.A seleção específica de uma escada de peixes do tipo seqüência de tanques, com passagem de fundo (tipo weir and orifice, na barragem da hidrelétrica de Itaipu (rio Paraná, foi avaliada através de amostragens no rio a jusante (amostragem trimestral em 1997 e em dois pontos ao longo da escada (10 e 27m de altura; nov/94 a jan/97 e nov/94 a fev/97, respectivamente. Das 65 espécies registradas no rio imediatamente a jusante da barragem, 27 foram capturadas na escada. As espécies com maior densidade na escada, em sua maioria migradoras, tiveram abundância moderada ou baixa a jusante. Entre as mais abundantes a jusante, apenas uma, não migradora, foi registrada na escada. A escada apresentou seleção negativa aos grandes pimelodídeos migradores que pode ser superada com a ampliação na escala do projeto. As amostragens evidenciaram baixa seletividade específica ao longo da escada, sendo seu modelo hidráulico satisfatório na atração e eficiente na ascensão de peixes.

  16. Spin transport in graphene nanostructures

    NARCIS (Netherlands)

    Guimaraes, M. H. D.; van den Berg, J. J.; Vera-Marun, I. J.; Zomer, P. J.; van Wees, B. J.

    2014-01-01

    Graphene is an interesting material for spintronics, showing long spin relaxation lengths even at room temperature. For future spintronic devices it is important to understand the behavior of the spins and the limitations for spin transport in structures where the dimensions are smaller than the

  17. Surface dependent structural phase transition in SrTiO 3 observed with spin relaxation of 8Li

    Science.gov (United States)

    Smadella, M.; Salman, Z.; Chow, K. H.; Egilmez, M.; Fan, I.; Hossain, M. D.; Kiefl, R. F.; Kreitzman, S. R.; Levy, C. D. P.; MacFarlane, W. A.; Mansour, A. I.; Morris, G. D.; Parolin, T. J.; Pearson, M.; Saadaoui, H.; Song, Q.; Wang, D.

    2009-04-01

    We investigate the 105 K structural phase transition in SrTiO 3 using depth controlled measurements of the spin relaxation of 8Li. The measurements were performed in zero external magnetic field and rely on the local electric field gradient (EFG) at the crystalline implantation site of the 8Li ( I=2) to hold the nuclear polarization. The tetragonal distortion accompanying the phase transition modifies the EFG in some 8Li implantation sites, resulting in an observable loss of 8Li polarization. This loss of polarization begins at a temperature T*=150 K, indicating there is some loss of cubic symmetry well above the bulk transition. We find that the value of T* is unaffected by the range of implantation depths available (10-150 nm); however, the temperature dependence of the polarization depends on the surface preparation of the SrTiO 3 sample.

  18. The Spin Structure of the Neutron and 3HE:. AN Overview of the Jlab Experiments in Hall a

    Science.gov (United States)

    Meziani, Z.-E.

    2001-02-01

    I shall discuss three experiments which form part of a comprehensive physics program aimed at the study of the spin structure of the neutron using a polarized 3He target and a polarized beam at JLab in Hall A. Results from the first experiment performed to evaluate the Gerasimov-Drell-Hearn (GDH) extended sum rule are presented and future approved measurements are discussed. The main goal of these experiments is to bridge our understanding of the strong interaction in the large Q2 regime where quarks and gluons are the relevant degrees of freedom to the low Q2 regime where constituent quarks and mesons seem to be more adequate for a description of the nucleon properties.

  19. Surface dependent structural phase transition in SrTiO{sub 3} observed with spin relaxation of {sup 8}Li

    Energy Technology Data Exchange (ETDEWEB)

    Smadella, M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Salman, Z. [Clarendon Laboratory, Department of Physics, Oxford University, Parks Road, Oxford OX1 3PU (United Kingdom); ISIS Facility, Rutherford-Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Chow, K.H.; Egilmez, M.; Fan, I. [Department of Physics, University of Alberta, Edmonton, AB, T6G 2G7 (Canada); Hossain, M.D. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Kiefl, R.F., E-mail: kiefl@triumf.c [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Canadian Institute for Advanced Research (Canada); Kreitzman, S.R.; Levy, C.D.P. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); MacFarlane, W.A. [Department of Chemistry, University of British Columbia, Vancouver, BC, V6T 1Z3 (Canada); Mansour, A.I. [Department of Physics, University of Alberta, Edmonton, AB, T6G 2G7 (Canada); Morris, G.D. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Parolin, T.J. [Department of Chemistry, University of British Columbia, Vancouver, BC, V6T 1Z3 (Canada); Pearson, M. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Saadaoui, H.; Song, Q.; Wang, D. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada)

    2009-04-15

    We investigate the 105 K structural phase transition in SrTiO{sub 3} using depth controlled measurements of the spin relaxation of {sup 8}Li. The measurements were performed in zero external magnetic field and rely on the local electric field gradient (EFG) at the crystalline implantation site of the {sup 8}Li (I=2) to hold the nuclear polarization. The tetragonal distortion accompanying the phase transition modifies the EFG in some {sup 8}Li implantation sites, resulting in an observable loss of {sup 8}Li polarization. This loss of polarization begins at a temperature T{sup *}=150K, indicating there is some loss of cubic symmetry well above the bulk transition. We find that the value of T{sup *} is unaffected by the range of implantation depths available (10-150 nm); however, the temperature dependence of the polarization depends on the surface preparation of the SrTiO{sub 3} sample.

  20. Multiple crossovers between positive and negative magnetoresistance versus field due to fragile spin structure in metallic GdPd3

    Science.gov (United States)

    Pandey, Abhishek; Mazumdar, Chandan; Ranganathan, R.; Johnston, D. C.

    2017-01-01

    Studies on the phenomenon of magnetoresistance (MR) have produced intriguing and application-oriented outcomes for decades–colossal MR, giant MR and recently discovered extremely large MR of millions of percents in semimetals can be taken as examples. We report here the discovery of novel multiple sign changes versus applied magnetic field of the MR in the cubic intermetallic compound GdPd3. Our study shows that a very strong correlation between magnetic, electrical and magnetotransport properties is present in this compound. The magnetic structure in GdPd3 is highly fragile since applied magnetic fields of moderate strength significantly alter the spin arrangement within the system–a behavior that manifests itself in the oscillating MR. Intriguing magnetotransport characteristics of GdPd3 are appealing for field-sensitive device applications, especially if the MR oscillation could materialize at higher temperature by manipulating the magnetic interaction through perturbations caused by chemical substitutions. PMID:28211520

  1. Structural and photo-physical properties of spin-coated poly (3-hexylthiophene) thin films

    CSIR Research Space (South Africa)

    Motaung, DE

    2009-07-01

    Full Text Available Regioregular poly(3-hexylthiophenes) (P3HTs) and its blends were studied regarding their structural and photo-physical properties using fullerene as an electron acceptor material. Photo-physical and structural characteristics of the polymer blends...

  2. Phase diagram of a bosonic ladder with two coupled chains

    International Nuclear Information System (INIS)

    Luthra, Meetu Sethi; Mishra, Tapan; Pai, Ramesh V.; Das, B. P.

    2008-01-01

    We study a bosonic ladder with two coupled chains using the finite-size density-matrix renormalization group method. We show that in a commensurate bosonic ladder the critical on-site interaction (U C ) for the superfluid to Mott insulator transition gets larger as the interchain hopping (t perpendicular ) increases. We analyze this quantum phase transition and obtain the phase diagram in the t perpendicular -U plane. We also consider the asymmetric case where the on-site interactions are different in the two chains and have shown that the system as a whole will not be in the Mott insulator phase unless both the chains have on-site interactions greater than the critical value

  3. Tests of prototype ITS-SSD Ladder and Fixators

    CERN Document Server

    Van den Brink, D J; CERN. Geneva; Nooren, G J L; Feofilov, G A; Igolkin, S N; Daudo, F; Giraudo, G; van den Broek, D J

    2000-01-01

    Abstract A prototype carbon fibre SSD ladder, produced in St.Petersburg, was equipped in Utrecht with mounting blocks, designed in Torino, for the fixation on the ITS cone. Instead of the cone, a specially designed jig was used. The mechanical properties were measured in order to find out whether the design and the production method are compliant with the requirements given in the TDR.

  4. Medical humanities in Nepal--snakes and ladders.

    Science.gov (United States)

    Shankar, P Ravi; Piryani, R M; Morgan, Huw; Thapa, T P

    2010-03-01

    In the last decade there has been a quantitative growth in medical schools in Nepal, a developing country in South Asia. Medical Humanities (MH) uses disciplines traditionally termed as the humanities in the pursuit of medical educational goals. The subject is slowly developing in Nepal. Sessions have been conducted at Manipal College of Medical Sciences, Pokhara and KIST Medical College, Lalitpur. In this article the authors examine inhibitory factors (snakes) and facilitating factors (ladders) for the development of the subject in Nepal.

  5. Internal structure transition of spin-on glass by electron beam irradiation

    International Nuclear Information System (INIS)

    Araki, Makoto; Taniguchi, Jun; Sawada, Nobuo; Utsumi, Takayuki; Miyamoto, Iwao

    2007-01-01

    The effects of electron beam (EB) irradiation on spin-on glass (SOG) were investigated using thermal desorption spectroscopy. We were able to employ heat treatment as a 'development process', since we discovered that heat treatment breaks different bonds in SOG depending on whether it is applied before or after EB irradiation of SOG. In the case, when heat treatment was applied before EB irradiation of SOG, it was possible to break the Si-C bond at about 500 deg. C. In the case, when heat treatment was applied after EB irradiation of SOG, on the other hand, the -SiC bond could be broken at a lower temperature of about 400 deg. C. Using this difference between the two bond-breaking temperatures, it was possible to develop SOG using thermal desorption development (TDD). Moreover, the bond-breaking mechanisms revealed that the organic components in SOG play an important role in TDD. Hence, in order to determine the influence of organic components on TDD, the development characteristics of SOG samples with 10% and 15% organic contents were investigated

  6. Studies of the spin-Hamiltonian parameters and defect structures for Gd3+ ions in zircon-structure silicates MSiO4 (M=Zr, Hf, Th).

    Science.gov (United States)

    Yang, Wei-Qing; Zheng, Wen-Chen

    2011-09-01

    The spin-Hamiltonian parameters (g factors g∥, g⊥ and zero-field splittings b2(0), b4(0), b4(4), b6(0), b6(4)) for 4f7 ion Gd3+ at the tetragonal M4+ site of zircon-structure silicates MSiO4 (M=Zr, Hf, Th) are calculated from a diagonalization (of energy matrix) method. The Hamiltonian concerning this energy matrix contains the free-ion, crystal-field interaction and Zeeman interaction terms and the 56×56 energy matrix is constructed by considering the ground multiplet 8S7/2 and the excited multiplets 6L7/2 (L=P, D, F, G, H, I). The defect structures of Gd3+ centers in the three MSiO4 crystals are yielded from the calculation. The results are discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Real-space localization and quantification of hole distribution in chain-ladder Sr3Ca11Cu24O41 superconductor.

    Science.gov (United States)

    Bugnet, Matthieu; Löffler, Stefan; Hawthorn, David; Dabkowska, Hanna A; Luke, Graeme M; Schattschneider, Peter; Sawatzky, George A; Radtke, Guillaume; Botton, Gianluigi A

    2016-03-01

    Understanding the physical properties of the chain-ladder Sr3Ca11Cu24O41 hole-doped superconductor has been precluded by the unknown hole distribution among chains and ladders. We use electron energy-loss spectrometry (EELS) in a scanning transmission electron microscope (STEM) at atomic resolution to directly separate the contributions of chains and ladders and to unravel the hole distribution from the atomic scale variations of the O-K near-edge structures. The experimental data unambiguously demonstrate that most of the holes lie within the chain layers. A quantitative interpretation supported by inelastic scattering calculations shows that about two holes are located in the ladders, and about four holes in the chains, shedding light on the electronic structure of Sr3Ca11Cu24O41. Combined atomic resolution STEM-EELS and inelastic scattering calculations is demonstrated as a powerful approach toward a quantitative understanding of the electronic structure of cuprate superconductors, offering new possibilities for elucidating their physical properties.

  8. New isomers and medium-spin structure of the 95Y nucleus

    International Nuclear Information System (INIS)

    Urban, W.; Sieja, K.; Simpson, G. S.; Faust, H.; Rzaca-Urban, T.; Zlomaniec, A.; Lukasiewicz, M.; Smith, A. G.; Durell, J. L.; Smith, J. F.; Varley, B. J.; Nowacki, F.; Ahmad, I.

    2009-01-01

    Excited states in 95 Y, populated following the spontaneous fission of 248 Cm and 252 Cf and following fission of 235 U induced by thermal neutrons, were studied by means of γ spectroscopy using the EUROGAM2 and GAMMASPHERE multidetector Ge arrays and the LOHENGRIN fission-fragment separator, respectively. We have found a new (17/2 - ) isomer in 95 Y at 3142.2 keV with a half-life of T 1/2 =14.9(5) ns. Another isomer was identified in 95 Y at 5022.1 keV and it was assigned a spin-parity (27/2 - ). For this isomer a half-life of T 1/2 =65(4) ns was determined and four decay branches were found, including an E3 decay. A new E3 decay branch was also found for the known, 1087.5-keV isomer in 95 Y, for which we measured a half-life of 51.2(9) μs. The B(E3) and B(E1) transition rates, of 2.0 and 3.8x10 -7 W.u., respectively, observed in 95 Y are significantly lower than in the neighboring 96 Zr core, suggesting that octupole correlations in this region are mainly due to the coupling of proton Δj=3 orbitals. Shell-model calculations indicate that the (27/2 - ) isomer in 95 Y corresponds to the πg 9/2 ν(g 7/2 h 11/2 ) maximally aligned configuration and that all three isomers in 95 Y decay, primarily, by M2 transitions between proton g 9/2 and f 5/2 orbitals.

  9. Coherent structural trapping through wave packet dispersion during photoinduced spin state switching

    DEFF Research Database (Denmark)

    Lemke, Henrik T.; Kjær, Kasper Skov; Hartsock, Robert

    2017-01-01

    is distinguished from the structural trapping dynamics, which launches a coherent oscillating wave packet (265 fs period), clearly identified as molecular breathing. Throughout the structural trapping, the dispersion of the wave packet along the reaction coordinate reveals details of intramolecular vibronic...

  10. Role of entropy and structural parameters in the spin-state transition of LaCoO3

    Science.gov (United States)

    Chakrabarti, Bismayan; Birol, Turan; Haule, Kristjan

    2017-11-01

    The spin-state transition in LaCoO3 has eluded description for decades despite concerted theoretical and experimental effort. In this study, we approach this problem using fully charge self-consistent density functional theory + embedded dynamical mean field theory (DFT+DMFT). We show from first principles that LaCoO3 cannot be described by a single, pure spin state at any temperature. Instead, we observe a gradual change in the population of higher-spin multiplets with increasing temperature, with the high-spin multiplets being excited at the onset of the spin-state transition followed by the intermediate-spin multiplets being excited at the metal-insulator-transition temperature. We explicitly elucidate the critical role of lattice expansion and oxygen octahedral rotations in the spin-state transition. We also reproduce, from first principles, that the spin-state transition and the metal-insulator transition in LaCoO3 occur at different temperature scales. In addition, our results shed light on the importance of electronic entropy in driving the spin-state transition, which has so far been ignored in all first-principles studies of this material.

  11. Spin dynamics and structural phase transitions in quasi-2D R sub 2 CuO sub 4 (R=Pr, Sm and Eu) antiferromagnetics

    CERN Document Server

    Golovenchits, E I

    2001-01-01

    One studied spin dynamics and dynamics of lattice in R sub 2 CuO sub 4 (R = Pr, Sm, and Eu) crystals within 20-250 GHz frequency range and within 50350 K temperature interval. One detected abrupt variation of absorption coefficient within wide range of frequencies above 120 GHz at 20, 80 and 150 K temperatures in R sub 2 CuO sub 4 (R = Pr, Sm, and Eu), respectively. Absorption jumpings result from structural phase transitions. Wide ranges of spin-wave excitations were observed in all examined crystals in high-temperature phase. Close to temperatures of phase transitions within wide range of frequencies including frequencies corresponding to ranges of spin-wave excitations one observed lines of a absorption caused by lattice dynamics

  12. Spin-orbit coupling effect on structural and magnetic properties of ConRh13-n (n = 0-13) clusters

    Science.gov (United States)

    Bai, Xi; Lv, Jin; Zhang, Fu-Qiang; Jia, Jian-Feng; Wu, Hai-Shun

    2018-04-01

    The effect of spin-orbit interaction on the structures and magnetism of ConRh13-n (n = 0-13) clusters have been systematically investigated by using the spin-orbit coupling (SOC) implementation of the density functional theory (DFT). The results calculated without SOC (NSOC) show that Rh13 prefers the double simple-cubic configuration, and icosahedron is the favorable structure for n = 1-9, while n ≥ 10, clusters favor the hexagonal bilayer structure. The inclusion of SOC in calculation does not change the geometries of clusters. Compared with that in NSOC calculation, although the binding energy per atom in clusters with same composition decreases in SOC calculation, the relative stability of clusters with different compositions does not change. An interesting result is that the spin moments of clusters for n = 1-9 are almost constant (21 μB). Spin-orbit interaction recovers orbital moment and its anisotropy by removing crystal-field effect in calculation. The destruction of bonding symmetry and relaxation of bonding account for high anisotropies of orbital moments in Co11Rh2 and CoRh12 clusters. With atomic composition (Co/Rh) around 4/9-5/8 and 9/4, the Co-Rh clusters exhibit high magnetic anisotropy energies.

  13. Structural features of spin-coated thin films of binary As{sub x}S{sub 100−x} chalcogenide glass system

    Energy Technology Data Exchange (ETDEWEB)

    Cook, J. [Austin Peay State University, Clarksville, TN 37075 (United States); Slang, S. [Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Golovchak, R. [Austin Peay State University, Clarksville, TN 37075 (United States); Jain, H. [International Materials Institute for New Functionality in Glass, Lehigh University, Bethlehem, PA 18015 (United States); Vlcek, M. [Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Kovalskiy, A., E-mail: kovalskyya@apsu.edu [Austin Peay State University, Clarksville, TN 37075 (United States)

    2015-08-31

    Spin-coating technology offers a convenient method for fabricating photostable chalcogenide glass thin films that are especially attractive for applications in IR optics. In this paper we report the structure of spin-coated As{sub x}S{sub 100−x} (x = 30, 35, 40) thin films as determined using high resolution X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, especially in relation to composition (i.e. As/S ratio) and preparation process variables. It was observed that As atoms during preparation have a tendency to precipitate out in close to stoichiometric compositions. The mechanism of bonding between the inorganic matrix and organic residuals is discussed based on the experimental data. A weak interaction between S ions and amine-based clusters is proposed as the basis of structural organization of the organic–inorganic interface. - Highlights: • As–S spin-coated chalcogenide thin films with different As/S were fabricated. • XPS measurements support the cluster-like structure of spin-coated films. • As{sub 2}O{sub 3} was confirmed as the composition of precipitate formed during dissolution. • Lack of As–As bonds explains the observed photostability of the thin films.

  14. Development of ultra-light pixelated ladders for an ILC vertex detector

    CERN Document Server

    Chon-Sen, N.; Claus, G.; De Masi, R.; Deveaux, M.; Dulinski, W.; Goffe, M.; Goldstein, J.; Gregor, I.-M.; Hu-Guo, Ch.; Imhoff, M.; Muntz, C.; Nomerotski, A.; Santos, C.; Schrader, C.; Specht, M.; Stroth, J.; Winter, M.

    2010-01-01

    The development of ultra-light pixelated ladders is motivated by the requirements of the ILD vertex detector at ILC. This paper summarizes three projects related to system integration. The PLUME project tackles the issue of assembling double-sided ladders. The SERWIETE project deals with a more innovative concept and consists in making single-sided unsupported ladders embedded in an extra thin plastic enveloppe. AIDA, the last project, aims at building a framework reproducing the experimental running conditions where sets of ladders could be tested.

  15. Analysis of Crystal Structure of Fe3O4 Thin Films Based on Iron Sand Growth by Spin Coating Method

    Science.gov (United States)

    Rianto, D.; Yulfriska, N.; Murti, F.; Hidayati, H.; Ramli, R.

    2018-04-01

    Recently, iron sand used as one of base materials in the steel industry. However, the content of iron sand can be used as starting materials in sensor technology in the form of thin films. In this paper, we report the analysis of crystal structure of magnetite thin film based on iron sand from Tiram’s Beach. The magnetic content of sand separated by a permanent magnet, then it was milled at 30 hours milling time. In order to increase the purity of magnetite, it washed after milling using aquades under magnetic separation by a magnet permanent. The thin film has been prepared using iron (III) nitrate by sol–gel technique. The precursor is resulted by dissolving magnetite in oxalic acid and nitric acid. Then, solution of iron (III) nitrate dissolved in ethylene glycol was applied on glass substrates by spin coating. The X-Ray Diffraction is operated thin film characterization. The structure of magnetite has been studied based on X-Ray Peaks that correspond to magnetite content of thin films.

  16. Quark spin-flavor layered structure with condensed π/sup 0/ field in Chiral bag model

    International Nuclear Information System (INIS)

    Tamagaki, R.; Tatsumi, T.

    1984-01-01

    In order to understand predispositions of high density matter, a new phase possibly arising from the neutron matter under π/sup 0/ condensation is studied in chiral bag model, as a facet in which both quark and pion degrees of freedom are incorporated in a well-developed situation of π/sup 0/ condensation. The aspects of this phase are characterized by the periodic layered structure of the two-dimensional quark matter with a specific spin-flavor order the π/sup 0/ field existent as the Nambu-Goldstone mode between the adjacent layers. Such quark configuration is caused due to the pion-quark coupling at the layer (bag) surface which drastically lowers quark energy. Energy properties of the system are examined, and it is shown that the one-gluon-exchange contribution provides the repulsive effect to prevent the layered structure from collapsing. This model provides an example which can be solved nonperturbatively in the chiral bag model and suggests the possibility of an intermediate stage which may appear prior to the phase transition to uniform quark matter

  17. 3D spin-flop transition in enhanced 2D layered structure single crystalline TlCo2Se2

    Science.gov (United States)

    Jin, Z.; Xia, Z.-C.; Wei, M.; Yang, J.-H.; Chen, B.; Huang, S.; Shang, C.; Wu, H.; Zhang, X.-X.; Huang, J.-W.; Ouyang, Z.-W.

    2016-10-01

    The enhanced 2D layered structure single crystalline TlCo2Se2 has been successfully fabricated, which exhibits field-induced 3D spin-flop phase transitions. In the case of the magnetic field parallel to the c-axis (B//c), the applied magnetic field induces the evolution of the noncollinear helical magnetic coupling into a ferromagnetic (FM) state with all the magnetization of the Co ion parallel to the c-axis. A striking variation of the field-induced strain within the ab-plane is noticed in the magnetic field region of 20-30 T. In the case of the magnetic field perpendicular to the c-axis (B  ⊥  c), the inter-layer helical antiferromagnetic (AFM) coupling may transform to an initial canted AFM coupling, and then part of it transforms to an intermediate metamagnetic phase with the alignment of two-up-one-down Co magnetic moments and finally to an ultimate FM coupling in higher magnetic fields. The robust noncollinear AFM magnetic coupling is completely destroyed above 30 T. In combination with the measurements of magnetization, magnetoresistance and field-induced strain, a complete magnetic phase diagram of the TlCo2Se2 single crystal has been depicted, demonstrating complex magnetic structures even though the crystal geometry itself gives no indication of the magnetic frustration.

  18. Spin, mass, and symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, M.E. [Stanford Univ., CA (United States)

    1994-12-01

    When the strong interactions were a mystery, spin seemed to be just a complication on top of an already puzzling set of phenomena. But now that particle physicists have understood the strong, weak, and electromagnetic interactions, to be gauge theories, with matter built of quarks and leptons, it is recognized that the special properties of spin 1/2 and spin 1 particles have taken central role in the understanding of Nature. The lectures in this summer school will be devoted to the use of spin in unravelling detailed questions about the fundamental interactions. Thus, why not begin by posing a deeper question: Why is there spin? More precisely, why do the basic pointlike constituents of Nature carry intrinsic nonzero quanta of angular momentum? Though the authos has found no definite answer to this question, the pursuit of an answer has led through a wonderful tangle of speculations on the deep structure of Nature. Is spin constructed or is it fundamental? Is it the requirement of symmetry? In the furthest flights taken, it seems that space-time itself is too restrictive a notion, and that this must be generalized in order to gain a full appreciation of spin. In any case, there is no doubt that spin must play a central role in unlocking the mysteries of fundamental physics.

  19. Spin, mass, and symmetry

    International Nuclear Information System (INIS)

    Peskin, M.E.

    1994-01-01

    When the strong interactions were a mystery, spin seemed to be just a complication on top of an already puzzling set of phenomena. But now that particle physicists have understood the strong, weak, and electromagnetic interactions, to be gauge theories, with matter built of quarks and leptons, it is recognized that the special properties of spin 1/2 and spin 1 particles have taken central role in the understanding of Nature. The lectures in this summer school will be devoted to the use of spin in unravelling detailed questions about the fundamental interactions. Thus, why not begin by posing a deeper question: Why is there spin? More precisely, why do the basic pointlike constituents of Nature carry intrinsic nonzero quanta of angular momentum? Though the authos has found no definite answer to this question, the pursuit of an answer has led through a wonderful tangle of speculations on the deep structure of Nature. Is spin constructed or is it fundamental? Is it the requirement of symmetry? In the furthest flights taken, it seems that space-time itself is too restrictive a notion, and that this must be generalized in order to gain a full appreciation of spin. In any case, there is no doubt that spin must play a central role in unlocking the mysteries of fundamental physics

  20. Gate voltage and structure parameter modulated spin splitting in AlGaN/GaN quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Li, M.; Zhang, R.; Zhang, Z.; Liu, B.; Fu, Deyi; Zhao, C.Z.; Xie, Z.L.; Xiu, X.Q.; Zheng, Y.D. [Nanjing National Lab of Microstructures, Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials and Department of Physics, Nanjing University, Nanjing 210093 (China)

    2011-01-15

    In this paper, considerable magnitude of spin splitting for the conduction subband at the Fermi energy is obtained in AlGaN quantum wells (QWs) grown along the c-axis. We have analyzed how the magnitude of spin splitting of the first electron subband in AlGaN QWs with different sheet carrier concentration changes as a function of applied gate voltage, well width, and Al content in the barrier. It is also found that the contribution to spin splitting from Dresselhaus term is much larger than that from Rashba term, the contribution of Dresselhaus term to the total spin splitting depends greatly on the carrier concentrations, the change of well width has little effect on total spin splitting, and the magnitude of spin splitting can be greatly modulated by Al content in the barrier, gate voltage, and sheet carrier concentration. The internal polarized electric field is crucial for considerable spin splitting in III-nitride QWs. Moreover, the magnitude of total spin splitting calculated here is comparable with other theoretical and experimental values observed in III-nitride heterostructures. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Tunneling effect of the spin-2 Bose condensate driven by external magnetic fields

    International Nuclear Information System (INIS)

    Yu Zhaoxian; Jiao Zhiyong

    2004-01-01

    In this Letter, we have studied tunneling effect of the spin-2 Bose condensate driven by external magnetic field. We find that the population transfers among spin-0 and spin-±1, spin-0 and spin-±2 exhibit the step structure under the external cosinusoidal magnetic field, respectively, but there do not exist step structure among spin-±1 and spin-±2. The tunneling current among spin-±1 and spin-±2 may exhibit periodically oscillation behavior, but among spin-0 and spin-±1, spin-0 and spin-±2, the tunneling currents exhibit irregular oscillation behavior

  2. Magnetic structure and interactions in the quasi-one-dimensional antiferromagnet CaV2O4

    Science.gov (United States)

    Pieper, O.; Lake, B.; Daoud-Aladine, A.; Reehuis, M.; Prokeš, K.; Klemke, B.; Kiefer, K.; Yan, J. Q.; Niazi, A.; Johnston, D. C.; Honecker, A.

    2009-05-01

    CaV2O4 is a spin-1 antiferromagnet, where the magnetic vanadium ions have an orbital degree of freedom and are arranged on quasi-one-dimensional zigzag chains. The first- and second-neighbor vanadium separations are approximately equal suggesting frustrated antiferromagnetic exchange interactions. High-temperature susceptibility and single-crystal neutron-diffraction measurements are used to deduce the dominant exchange paths and orbital configurations. The results suggest that at high temperatures CaV2O4 behaves as a Haldane chain, but at low temperatures, it is a spin-1 ladder. These two magnetic structures are explained by different orbital configurations and show how orbital ordering can drive a system from one exotic spin Hamiltonian to another.

  3. Measurement of the spin structure of the deuteron in the DIS region

    Czech Academy of Sciences Publication Activity Database

    Ageev, E.; Alexakhin, V.; Alexandrov, Y.; Alexeev, G.; Amoroso, A.; Badelek, B.; Balestra, F.; Ball, J.; Baum, G.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Burtin, E.; Bussa, M.; Bytchkov, V.; Cerini, L.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.; Costa, S.; Crespo, M.; d'Hose, N.; Dalla Torre, S.; Dasgupta, S. S.; De Masi, R.; Dedek, N.; Denisov, O.; Dhara, L.; Diaz Kavka, V.; Dinkelbach, A.; Dolgopolov, A.; Donskov, S.; Dorofeev, V.; Doshita, N.; Duic, V.; Dünnweber, W.; Ehlers, J.; Eversheim, P.; Eyrich, W.; Fabro, M.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger jr., M.; Fischer, H.; Franz, J.; Friedrich, J.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.; Grajek, O.; Grasso, A.; Grube, B.; Grünemaier, A.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Ijaduola, R.; Ilgner, C.; Ioukaev, A.; Ishimoto, S.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N. I.; Kabuss, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G.; Khokhlov, Y.; Khomutov, N.; Kisselev, Y.; Klein, F.; Koblitz, S.; Koivuniemi, J.; Kolosov, V.; Komissarov, E.; Kondo, K.; Königsmann, K.; Konoplyannikov, A.; Konorov, I.; Konstantinov, V.; Korentchenko, A.; Korzenev, A.; Kotzinian, A.; Koutchinski, N.; Kowalik, K.; Kravchuk, N.; Krivokhizhin, G.; Kroumchtein, Z.; Kuhn, R.; Kunne, F.; Kurek, K.; Ladygin, M.; Lamanna, M.; Le Goff, J.; Leberig, M.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.; Manuilov, I.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Matsuda, T.; Maximov, A.; Medved, K.; Meyer, W.; Mielech, A.; Mikhailov, Y.; Moinester, M.; Nähle, O.; Nassalski, J.; Neliba, S.; Neyret, D.; Nikolaenko, V.; Nozdrin, A.; Obraztsov, V.; Olshevsky, A.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Pereira, H.; Peshekhonov, D.; Peshekhonov, V.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polyakov, V.; Popov, A.; Pretz, J.; Quintans, C.; Ramos, S.; Rebourgeard, P.; Reicherz, G.; Reymann, J.; Rith, K.; Rozhdestvensky, A.; Rondio, E.; Sadovski, A.; Saller, E.; Samoylenko, V.; Sandacz, A.; Sans, M.; Sapozhnikov, M.; Savin, I.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, H.; Schmitt, L.; Shevchenko, O.; Shishkin, A.; Siebert, H.; Sinha, L.; Sissakian, A.; Skachkova, A.; Slunecka, M.; Smirnov, G.; Sozzi, F.; Sugonyaev, V.; Srnka, Aleš; Stinzing, F.; Stolarski, M.; Sulc, M.; Sulej, R.; Takabayashi, N.; Tchalishev, V.; Tassarotto, F.; Teufel, A.; Thers, D.; Tkatchev, L.; Toeda, T.; Tretyak, V.; Trousov, S.; Varanda, M.; Virius, M.; Vlassov, N.; Wagner, M.; Webb, R.; Weise, E.; Weitzel, Q.; Wiedner, U.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wislicki, W.; Zanetti, A.; Zaremba, K.; Zhao, J.; Ziegler, R.; Zvyagin, A.

    2005-01-01

    Roč. 612, 3-4 (2005), s. 154-164 ISSN 0370-2693 R&D Projects: GA MŠk(CZ) ME 492 Keywords : deep inelastic scattering * structure functions Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.301, year: 2005

  4. Spin structure and magnetic frustration in multiferroic RMn2O5 (R=Tb,Ho,Dy)

    NARCIS (Netherlands)

    Blake, G.R.; Chapon, L.C.; Radaelli, P.G.; Park, S.; Hur, N.; Cheong, S-W.; Rodríguez-Carvajal, J.

    2005-01-01

    We have studied the crystal and magnetic structures of the magnetoelectric materials RMn2O5 (R=Tb,Ho,Dy) using neutron diffraction as a function of temperature. All three materials display incommensurate antiferromagnetic ordering below 40 K, becoming commensurate on further cooling. For R=Tb,Ho, a

  5. Structural and optical properties of SnO{sub 2} nano films by spin-coating method

    Energy Technology Data Exchange (ETDEWEB)

    Uysal, Bengü Özuğur, E-mail: bozugur@khas.edu.tr [Department of Energy Systems Engineering, Faculty of Engineering and Natural Sciences, Kadir Has University, Fatih, Istanbul, 34083 (Turkey); Arıer, Ümit Özlem Akkaya [Department of Physics, Faculty of Science and Letters, Mimar Sinan Fine Arts University, Beşiktaş, Istanbul 34349 (Turkey)

    2015-09-30

    Highlights: • SnO{sub 2} nano films were deposited on glass substrates by spin-coating method. • The structural and optical properties of SnO{sub 2} nano films were characterized. • The properties of SnO{sub 2} nano films were controlled by changing the SnCl{sub 2}:water ratio. • The activation energy and the band gap energy values of the films were determined. - Abstract: In this work, tin oxide (SnO{sub 2}) nano films were deposited on glass substrates with different water content using the sol–gel spin-coating method. SnO{sub 2} is a wide band gap semiconductor and it belongs to the class of transparent conductive oxides (TCO). The influence of the water content and the heat treatment temperature on the structural and optical properties of the thin films is characterized by X-ray diffractometer (XRD), scanning electron microscope, atomic force microscope, ultraviolet–visible spectrophotometer, and spectrophotometer. Crystallite size of nano SnO{sub 2} films was controlled by SnCl{sub 2}:water ratios. The most significant characteristic of nano materials is the increase in surface area as particle size decreases. XRD studies showed that the formation of tetragonal rutil phase was initiated at an annealing temperature close to 450 °C. The activation energy of nano SnO{sub 2} films for particle growth was calculated. The film has an activation energy of 42.8 kJ/mol, and the optical band gap of 3.02-3.35 eV is proportional to the SnCl{sub 2}:water ratio. The quantum size effect of nano particles was confirmed by the band gap energy shift, using ultraviolet–visible spectroscopy (UV–vis). SnO{sub 2} films have been considered as one of the most promising functional materials due to their wide direct band-gap, and excellent electrical and optical properties. Those properties of SnO{sub 2} films allow them to be used in electronic and optoelectronic devices like gas sensors, solar cells and lithium batteries etc.

  6. Structural and photo-physical properties of spin-coated poly(3-hexylthiophene) thin films

    International Nuclear Information System (INIS)

    Motaung, David E.; Malgas, Gerald F.; Arendse, Christopher J.; Mavundla, Sipho E.; Knoesen, D.

    2009-01-01

    Regioregular poly(3-hexylthiophenes) (P3HTs) and its blends were studied regarding their structural and photo-physical properties using fullerene as an electron acceptor material. Photo-physical and structural characteristics of the polymer blends were studied using UV-vis spectroscopy, photoluminescence (PL), Fourier transform infrared absorption (FTIR) spectroscopy and Raman spectroscopy analysis. Films based on the polymer blends with C 60 showed photo-induced absorption characteristic for charged excitations. The absorption spectra of the rr-P3HT exhibit a shift to higher energies (blue shift) of the π-π* inter-band transition upon mixing with C 60 . A distinctive photoluminescence quenching effect is observed indicating photo-induced electron transfer. The complete reduction of PL of P3HT after mixing with C 60 in a 1:1 weight ratio indicates an effective charge transfer from P3HT to C 60 .

  7. The Spin Structure Function of the Proton from SLAC Experiment E155

    Energy Technology Data Exchange (ETDEWEB)

    McKee, P

    2004-02-17

    Experiment E155 at the Stanford Linear Accelerator Center (SLAC) measured the longitudinal and transverse deep inelastic structure functions of the proton and deuteron using a polarized, 48.3 GeV electron beam and solid polarized targets of ammonia ({sup 15}NH{sub 3}) for proton measurements and lithium deuteride ({sup 6}Li{sup 2}H) for deuteron measurements. Three electromagnetic spectrometers at angles of 2.75{sup o}, 5.5{sup o}, and 10.5{sup o} measured the scattered electrons. This work presents an analysis of the longitudinal structure function of the proton, g{sub 1}{sup p}(x, Q{sup 2}). Included is a re-analysis of the proton target polarization data that for the first time corrects a problem encountered which altered those measurements.

  8. Spins in chemistry

    CERN Document Server

    McWeeny, Roy

    2004-01-01

    Originally delivered as a series of lectures, this volume systematically traces the evolution of the ""spin"" concept from its role in quantum mechanics to its assimilation into the field of chemistry. Author Roy McWeeny presents an in-depth illustration of the deductive methods of quantum theory and their application to spins in chemistry, following the path from the earliest concepts to the sophisticated physical methods employed in the investigation of molecular structure and properties. Starting with the origin and development of the spin concept, the text advances to an examination of sp

  9. Multi-material size optimization of a ladder frame chassis

    Science.gov (United States)

    Baker, Michael

    The Corporate Average Fuel Economy (CAFE) is an American fuel standard that sets regulations on fuel economy in vehicles. This law ultimately shapes the development and design research for automakers. Reducing the weight of conventional cars offers a way to improve fuel efficiency. This research investigated the optimality of an automobile's ladder frame chassis (LFC) by conducting multi-objective optimization on the LFC in order to reduce the weight of the chassis. The focus of the design and optimization was a ladder frame chassis commonly used for mass production light motor vehicles with an open-top rear cargo area. This thesis is comprised of two major sections. The first looked to perform thickness optimization in the outer walls of the ladder frame. In the second section, many multi-material distributions, including steel and aluminium varieties, were investigated. A simplified model was used to do an initial hand calculation analysis of the problem. This was used to create a baseline validation to compare the theory with the modeling. A CAD model of the LFC was designed. From the CAD model, a finite element model was extracted and joined using weld and bolt connectors. Following this, a linear static analysis was performed to look at displacement and stresses when subjected to loading conditions that simulate harsh driving conditions. The analysis showed significant values of stress and displacement on the ends of the rails, suggesting improvements could be made elsewhere. An optimization scheme was used to find the values of an all steel frame an optimal thickness distribution was found. This provided a 13% weight reduction over the initial model. To advance the analysis a multi-material approach was used to push the weight savings even further. Several material distributions were analyzed and the lightest utilized aluminium in all but the most strenuous subjected components. This enabled a reduction in weight of 15% over the initial model, equivalent to

  10. Breathers in Josephson junction ladders: Resonances and electromagnetic wave spectroscopy

    DEFF Research Database (Denmark)

    Miroshnichenko, A. E.; Flach, S.; Fistul, M.

    2001-01-01

    We present a theoretical study of the resonant interaction between dynamical localized states (discrete breathers) and linear electromagnetic excitations (EE's) in Josephson junction ladders. By making use of direct numerical simulations we find that such an interaction manifests itself by resonant...... steps and various sharp switchings (voltage jumps) in the current-voltage characteristics. Moreover, the power of ac oscillations away from the breather center (the breather tail) displays singularities as the externally applied dc bias decreases. All these features may be mapped to the spectrum of EE...

  11. Education Career Ladder, AFSC 751X0. Volume II.

    Science.gov (United States)

    1981-02-01

    I AD-A099 152 AIR FORCE OCCUPATIONAL MEASUREMENT CENTER RANDOLPH AFO TX F/S 5/9 I EDUCATION CAREER LADDER, AFSC 7151X0. VOLUME II.(U) I UNCLASSIFIED...percentages of incumbents, such as: service operated schools, education surveys, and support for dependent children . In terms of the main aspect of...DETERMINE BASE REQUIREMENTS FOR EDUCATIONAL SERVICE PROGRAMS 6.45 24 F183 SCHEDULE SCHOOL TRANSPORTATION OF DEPENDENT CHILDREN 6.44 15 E166 REVIEW

  12. Rotational high spin structures in doubly-odd in {sup 184}Au

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, F.; Roussiere, B.; Sauvage, J.; Bourgeois, C.; Korichi, A. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Hojman, D.; Kreiner, A.J.; Davidson, J.; Davidson, M.; Debray, M. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Dept. de Fisica; Knipper, A. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Marguier, G. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire] [and others

    1995-12-31

    Excited states in the doubly-odd {sup 184}Au nucleus have been studied by in-beam {gamma}-ray spectroscopy. This nucleus was produced through the fusion-evaporation reactions {sup 165}Ho({sup 24}Mg, 5n), {sup 170}Yb({sup 19}F, 5n) and {sup 161}Dy({sup 27}Al, 4n). Different rotational band structures have been observed and interpreted as specific couplings of proton and neutron single-particle excitations present in neighboring odd Au and Pt nuclei. (author). 34 refs.; Submitted to Physical Review, C (US).

  13. The local physical structure of amorphous hydrogenated boron carbide: insights from magic angle spinning solid-state NMR spectroscopy.

    Science.gov (United States)

    Paquette, Michelle M; Li, Wenjing; Sky Driver, M; Karki, Sudarshan; Caruso, A N; Oyler, Nathan A

    2011-11-02

    Magic angle spinning solid-state nuclear magnetic resonance spectroscopy techniques are applied to the elucidation of the local physical structure of an intermediate product in the plasma-enhanced chemical vapour deposition of thin-film amorphous hydrogenated boron carbide (B(x)C:H(y)) from an orthocarborane precursor. Experimental chemical shifts are compared with theoretical shift predictions from ab initio calculations of model molecular compounds to assign atomic chemical environments, while Lee-Goldburg cross-polarization and heteronuclear recoupling experiments are used to confirm atomic connectivities. A model for the B(x)C:H(y) intermediate is proposed wherein the solid is dominated by predominantly hydrogenated carborane icosahedra that are lightly cross-linked via nonhydrogenated intraicosahedral B atoms, either directly through B-B bonds or through extraicosahedral hydrocarbon chains. While there is no clear evidence for extraicosahedral B aside from boron oxides, ∼40% of the C is found to exist as extraicosahedral hydrocarbon species that are intimately bound within the icosahedral network rather than in segregated phases.

  14. Structural, Optical Constants and Photoluminescence of ZnO Thin Films Grown by Sol-Gel Spin Coating

    Directory of Open Access Journals (Sweden)

    Abdel-Sattar Gadallah

    2013-01-01

    Full Text Available We report manufacturing and characterization of low cost ZnO thin films grown on glass substrates by sol-gel spin coating method. For structural properties, X-ray diffraction measurements have been utilized for evaluating the dominant orientation of the thin films. For optical properties, reflectance and transmittance spectrophotometric measurements have been done in the spectral range from 350 nm to 2000 nm. The transmittance of the prepared thin films is 92.4% and 88.4%. Determination of the optical constants such as refractive index, absorption coefficient, and dielectric constant in this wavelength range has been evaluated. Further, normal dispersion of the refractive index has been analyzed in terms of single oscillator model of free carrier absorption to estimate the dispersion and oscillation energy. The lattice dielectric constant and the ratio of free carrier concentration to free carrier effective mass have been determined. Moreover, photoluminescence measurements of the thin films in the spectral range from 350 nm to 900 nm have been presented. Electrical measurements for resistivity evaluation of the films have been done. An analysis in terms of order-disorder of the material has been presented to provide more consistency in the results.

  15. The spin-dependent structure function $g_{1}(x)$ of the deuteron from polarized deep-inelastic muon scattering

    CERN Document Server

    Adams, D; Adeva, B; Akdogan, T; Arik, E; Arvidson, A; Badelek, B; Ballintijn, M K; Bardin, Dimitri Yuri; Bardin, G; Baum, G; Berglund, P; Betev, L; Bird, I G; Birsa, R; Björkholm, P; Bonner, B E; De Botton, N R; Boutemeur, M; Bradamante, Franco; Bravar, A; Bressan, A; Bültmann, S; Burtin, E; Cavata, C; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Derro, B R; Deshpande, A A; Dhawan, S K; Dulya, C M; Dyring, A; Eichblatt, S; Faivre, Jean-Claude; Fasching, D; Feinstein, F; Fernández, C; Frois, Bernard; Gallas, A; Garzón, J A; Gaussiran, T; Giorgi, M A; von Goeler, E; Gómez, F; Gracia, G; De Groot, N; Grosse-Perdekamp, M; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; Kabuss, E M; Kageya, T; Kalinovskaya, L V; Karev, A G; Kessler, H J; Ketel, T; Kiryluk, J; Kishi, A; Kiselev, Yu F; Klostermann, L; Krämer, Dietrich; Krivokhizhin, V G; Kröger, W; Kukhtin, V V; Kurek, K; Kyynäräinen, J; Lamanna, M; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Lindqvist, T; Litmaath, M; Loewe, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Van Middelkoop, G; Miller, D; Mori, K; Moromisato, J H; Nagaitsev, A P; Nassalski, J P; Naumann, Lutz; Niinikoski, T O; Oberski, J; Ogawa, A; Ozben, C; Parks, D P; Perrot-Kunne, F; Peshekhonov, V D; Piegaia, R; Pinsky, L; Platchkov, S K; Pló, M; Polec, J; Pose, D; Postma, H; Pretz, J; Puntaferro, R; Pussieux, T; Pyrlik, J; Rädel, G; Rijllart, A; Roberts, J B; Rock, S E; Rodríguez, M; Rondio, Ewa; Rosado, A; Sabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Schüler, K P; Seitz, R; Semertzidis, Y K; Sever, F; Shanahan, P; Sichtermann, E P; Simeoni, F; Smirnov, G I; Staude, A; Steinmetz, A; Steigler, U; Stuhrmann, H B; Szleper, M; Teichert, K M; Tessarotto, F; Tlaczala, W; Trentalange, S; Tripet, A; Ünel, G; Velasco, M; Vogt, J; Voss, Rüdiger; Weinstein, R; Whitten, C; Windmolders, R; Willumeit, R; Wislicki, W; Witzmann, A; Yañez, A; Ylöstalo, J; Zanetti, A M; Zaremba, K; Zhao, J

    1997-01-01

    We present a new measurement of the spin-dependent structure function $g_{1}^{\\rm d}$ of the deuteron from deep inelastic scattering of 190 GeV polarized muons on polarized deuterons. The results are combined with our previous measurements of $g_{1}^{\\rm d}$. A perturbative QCD evolution in next-to-leading order is used to compute $g_{1}^{\\rm d}(x)$ at a constant $Q^{2}$. At $Q^{2} = 10$ GeV$^{2}$, we obtain a first moment $\\Gamma_{1}^{\\rm d} = \\int_{0}^{1} g_{1}^{\\rm d}{\\rm d}x = 0.041 \\pm 0.008$, a flavour-singlet axial charge of the nucleon $a_{0} = 0.30 \\pm 0.08$, and an axial charge of the strange quark $a_{s} = -0.09 \\pm 0.03$. Using our earlier determination of $\\Gamma_{1}^{\\rm p}$, we obtain $\\Gamma_1^{\\rm p} - \\Gamma_1^{\\rm n} = 0.183 \\pm 0.035$ at $Q^2 = 10\\,\\mbox{GeV}^2$. This result is in agreement with the Bjorken sum rule which predicts $\\Gamma_1^{\\rm p} - \\Gamma_1^{\\rm n} = 0.186 \\pm 0.002$ at the same $Q^2$.

  16. Significant manipulation of output performance of a bridge-structured spin valve magnetoresistance sensor via an electric field

    Science.gov (United States)

    Zhang, Yue; Yan, Baiqian; Ou-Yang, Jun; Wang, Xianghao; Zhu, Benpeng; Chen, Shi; Yang, Xiaofei

    2016-01-01

    Through principles of spin-valve giant magnetoresistance (SV-GMR) effect and its application in magnetic sensors, we have investigated electric-field control of the output performance of a bridge-structured Co/Cu/NiFe/IrMn SV-GMR sensor on a PZN-PT piezoelectric substrate using the micro-magnetic simulation. We centered on the influence of the variation of uniaxial magnetic anisotropy constant (K) of Co on the output of the bridge, and K was manipulated via the stress of Co, which is generated from the strain of a piezoelectric substrate under an electric field. The results indicate that when K varies between 2 × 104 J/m3 and 10 × 104 J/m3, the output performance can be significantly manipulated: The linear range alters from between -330 Oe and 330 Oe to between -650 Oe and 650 Oe, and the sensitivity is tuned by almost 7 times, making it possible to measure magnetic fields with very different ranges. According to the converse piezoelectric effect, we have found that this variation of K can be realized by applying an electric field with the magnitude of about 2-20 kV/cm on a PZN-PT piezoelectric substrate, which is realistic in application. This result means that electric-control of SV-GMR effect has potential application in developing SV-GMR sensors with improved performance.

  17. Precision Determination of the Neutron Spin Structure Function {ital g}{sup {ital n}}{sub {ital 1}}

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, R.G.; Bosted, P.E.; Fellbaum, J.N.; Reyna, D.; Rock, S.E.; Sorrell, L.; Szalata, Z.M.; Toole, T. [American University, Washington, D.C. 20016 (United States); Shapiro, G. [University of California, Berkeley, California 94720 (United States); Breton, V.; Fonvieille, H.; Incerti, S. [LPC IN2P3/CNRS, Univ. Blaise Pascal, F-63170 Aubiere Cedex (France); Meyer, W. [University of Bonn, Nussallee 12, D-5300 Bonn (Germany); Averett, T.; Hughes, E.W. [California Institute of Technology, Pasadena, California 91125 (United States); Borel, H.; Lombard-Nelsen, R.; Marroncle, J.; Sabatie, F.; Staley, F.; Terrien, Y. [DAPNIA, Saclay, 91191 Gif-sur-Yvette Cedex (France); Anderson, B.D.; Khayat, M.; Manley, D.M.; Olson, M.; Petratos, G.G.; Watson, J.W.; Zhang, W. [Kent State University, Kent, Ohio 44242 (United States); Ghazikhanian, V.; Igo, G. [University of California, Los Angeles, California 90024-1547 (United States); Berisso, C.M.; Churchwell, S.; Hicks, R.S.; Kolomensky, Y.G.; Peterson, G.A.; Shaw, J. [University of Massachusetts, Amherst, Massachusetts 01003 (United States); Chupp, T.E.; Coulter, K.P.; Smith, T.B.; Welsh, R.C. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Thompson, A.K. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Miller, D. [Northwestern University, Evanston, Illinois 60201 (United States); Kuhn, S.E.; Raue, B.; Wesselmann, F. [Old Dominion University, Norfolk, Virginia 23529 (United States); Raines, P. [University of Pennsylvania, Philadelphia, Pennsylvania 19104-6317 (United States); Bogorad, P.; Cates, G.D.; Kumar, K.; Romalis, M.V. [Princeton University, Princeton, New Jersey 08544 (United States); Marvin, T. [Southern Oregon State College, Ashland, Oregon 97520 (United States); Decowski, P. [Smith College, Northampton, Massachusetts 01063 (United States); Akagi, T.; Anthony, P.L.; Buenerd, M.J.; Daoudi, M.; Erickson, R.; and others

    1997-07-01

    We report on a precision measurement of the neutron spin structure function g{sup n}{sub 1} using deep inelastic scattering of polarized electrons by polarized {sup 3}He . For the kinematic range 0.014{lt}x{lt}0.7 and 1{lt}Q{sup 2}{lt}17(GeV /c){sup 2} , we obtain {integral}{sub 0.014}{sup 0.7}g{sup n}{sub 1}(x)dx={minus}0.036{plus_minus}0.004(stat){plus_minus}0.005(syst) at an average Q{sup 2}=5(GeV/c){sup 2}. We find relatively large negative values for g{sup n}{sub 1} at low x . The results call into question the usual Regge theory method for extrapolating to x=0 to find the full neutron integral {integral}{sub 0}{sup 1}g{sup n}{sub 1}(x)dx, needed for testing the quark-parton model and QCD sum rules. {copyright} {ital 1997} {ital The American Physical Society}

  18. A density functional theory investigation of the electronic structure and spin moments of magnetite

    KAUST Repository

    Noh, Junghyun

    2014-08-01

    We present the results of density functional theory (DFT) calculations on magnetite, Fe3O4, which has been recently considered as electrode in the emerging field of organic spintronics. Given the nature of the potential applications, we evaluated the magnetite room-temperature cubic phase in terms of structural, electronic, and magnetic properties. We considered GGA (PBE), GGA + U (PBE + U), and range-separated hybrid (HSE06 and HSE(15%)) functionals. Calculations using HSE06 and HSE(15%) functionals underline the impact that inclusion of exact exchange has on the electronic structure. While the modulation of the band gap with exact exchange has been seen in numerous situations, the dramatic change in the valence band nature and states near the Fermi level has major implications for even a qualitative interpretation of the DFT results. We find that HSE06 leads to highly localized states below the Fermi level while HSE(15%) and PBE + U result in delocalized states around the Fermi level. The significant differences in local magnetic moments and atomic charges indicate that describing room-temperature bulk materials, surfaces and interfaces may require different functionals than their low-temperature counterparts.

  19. Spin current

    CERN Document Server

    Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi

    2017-01-01

    Since the discovery of the giant magnetoresistance effect in magnetic multilayers in 1988, a new branch of physics and technology, called spin-electronics or spintronics, has emerged, where the flow of electrical charge as well as the flow of electron spin, the so-called “spin current,” are manipulated and controlled together. The physics of magnetism and the application of spin current have progressed in tandem with the nanofabrication technology of magnets and the engineering of interfaces and thin films. This book aims to provide an introduction and guide to the new physics and applications of spin current, with an emphasis on the interaction between spin and charge currents in magnetic nanostructures.

  20. Spins, Parity, Excitation Energies, and Octupole Structure of an Excited Superdeformed Band in 194Hg and Implications for Identical Bands

    Science.gov (United States)

    Hackman, G.; Khoo, T. L.; Carpenter, M. P.; Lauritsen, T.; Lopez-Martens, A.; Calderin, I. J.; Janssens, R. V.; Ackermann, D.; Ahmad, I.; Agarwala, S.; Blumenthal, D. J.; Fischer, S. M.; Nisius, D.; Reiter, P.; Young, J.; Amro, H.; Moore, E. F.; Hannachi, F.; Korichi, A.; Lee, I. Y.; Macchiavelli, A. O.; Døssing, T.; Nakatsukasa, T.

    1997-11-01

    An excited superdeformed band in 194Hg, observed to decay directly to both normal-deformed and superdeformed yrast states, is proposed to be a Kπ = 2- octupole vibrational band, based on its excitation energies, spins, and likely parity. The transition energies are identical to those of the yrast superdeformed band in 192Hg, but originate from levels with different spins and parities. The evolution of transition energies with spin suggests that cancellations between pairing and particle alignment are partly responsible for the identical transition energies.

  1. Trichromatic π-Pulse for Ultrafast Total Inversion of a Four-Level Ladder System

    Directory of Open Access Journals (Sweden)

    Carles Serrat

    2015-11-01

    Full Text Available We present a numerical solution for complete population inversion in a four-level ladder system obtained by using a full π-pulse illumination scheme with resonant ultrashort phase-locked Gaussian laser pulses. We find that a set of pulse areas such as √3π , √2π , and √3π completely inverts the four-level system considering identical effective dipole coupling coefficients. The solution is consistent provided the involved electric fields are not too strong and it is amply accurate also in the case of diverse transition dipole moments. We study the effect of detuning and chirp of the laser pulses on the complete population inversion using the level structure of atomic sodium interacting with ps and fs pulses as an example. Our result opens the door for multiple applications such as efficient ultrashort pulse lasing in the UV or the engineering of quantum states for quantum computing.

  2. Towers and ladders: Infinite parameter symmetries in Kaluza-Klein theories

    International Nuclear Information System (INIS)

    Aulakh, C.S.

    1984-05-01

    We introduce a class of infinite dimensional algebras with a 'generalized loop structure' by considering the global symmetries of the four dimensional Lagrangian obtained by compactifying general relativity coupled to Yang-Mills in six dimensions down to M 4 xS 2 . The generalization to arbitrary dimensions is then obvious. We show by explicit construction that such algebras possess an infinite number of finite sub-algebras. Among which, for the six dimensional case, is so(1,3) realized on S 2 with vanishing Casimir invariants. This so(1,3) may be interpreted, in accord with a previous conjecture of Salam and Strathdee [Ann. Phys. 141, 316(1982)], as the 'ladder' symmetry for the Kaluza-Klein towers. (author)

  3. A renormalization approach to describe charge transport in quasiperiodic dangling backbone ladder (DBL)-DNA molecules

    Energy Technology Data Exchange (ETDEWEB)

    Sarmento, R.G. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Fulco, U.L. [Departamento de Biofisica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Albuquerque, E.L., E-mail: eudenilson@gmail.com [Departamento de Biofisica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Caetano, E.W.S. [Instituto Federal de Educacao, Ciencia e Tecnologia do Ceara, 60040-531 Fortaleza, CE (Brazil); Freire, V.N. [Departamento de Fisica, Universidade Federal do Ceara, 60455-760 Fortaleza, CE (Brazil)

    2011-10-31

    Highlights: → One-step renormalization approach to describe the DBL-DNA molecule. → Electronic tight-binding Hamiltonian model. → A quasiperiodic sequence to mimic the DNA nucleotides arrangement. → Electronic transmission spectra. → I-V characteristics. -- Abstract: We study the charge transport properties of a dangling backbone ladder (DBL)-DNA molecule focusing on a quasiperiodic arrangement of its constituent nucleotides forming a Rudin-Shapiro (RS) and Fibonacci (FB) Poly (CG) sequences, as well as a natural DNA sequence (Ch22) for the sake of comparison. Making use of a one-step renormalization process, the DBL-DNA molecule is modeled in terms of a one-dimensional tight-binding Hamiltonian to investigate its transmissivity and current-voltage (I-V) profiles. Beyond the semiconductor I-V characteristics, a striking similarity between the electronic transport properties of the RS quasiperiodic structure and the natural DNA sequence was found.

  4. Of towers and ladders: Infinite parameter symmetries in Kaluza-Klein theories

    International Nuclear Information System (INIS)

    Aulakh, C.S.

    1984-01-01

    We introduce a class of infinite dimensional algebras with a 'generalized loop structure' by considering the global symmetries of the four-dimensional lagrangian obtained by compactifying general relativity coupled to Yang-Mills in six-dimensions down to M 4 x S 2 . The generalization to arbitrary dimensions is then obvious. We show by explicit construction that such algebras possess an infinite number of finite sub-algebras among which, for the six-dimensional case, is so (1, 3), realized on S 2 with vanishing Casimir invariants. This so (1, 3) may be interpreted, in accordance with a previous conjecture of Salam and Strathdee, as the 'ladder' symmetry for the Kaluza-Klein towers. (orig.)

  5. Spectral properties of an extended Hubbard ladder with long range anti-ferromagnetic order

    Science.gov (United States)

    Yang, Chun; Feiguin, Adrian

    We study the spectral properties of a Hubbard ladder with anti-ferromagnetic long range order by introducing a staggered Heisenberg interaction that decays algebraically. Unlike an alternating field or the t -Jz model, our problem preserves both SU (2) and translational invariance. We solve the problem with the time-dependent density matrix renormalization group and analyze the binding between holons and spinons and the structure of the elementary excitations. We discuss the implications in the context of the 2D Hubbard model at, and away from half-filling by using cluster perturbation theory (CPT). AF acknowledges the U.S. Department of Energy, Office of Basic Energy Sciences, for support under Grant DE-SC0014407.

  6. Spin Electronics

    Science.gov (United States)

    2003-08-01

    applications, a ferromagnetic metal may be used as a source of spin-polarized electronics to be injected into a semiconductor, a superconductor or a...physical phenomena in II-VI and III-V semiconductors. In II-VI systems, the Mn2+ ions act to boost the electron spin precession up to terahertz ...conductors, proximity effect between ferromagnets and superconductors , and the effects of spin injection on the physical properties of the

  7. Spin doctoring

    OpenAIRE

    Vozková, Markéta

    2011-01-01

    1 ABSTRACT The aim of this text is to provide an analysis of the phenomenon of spin doctoring in the Euro-Atlantic area. Spin doctors are educated people in the fields of semiotics, cultural studies, public relations, political communication and especially familiar with the infrastructure and the functioning of the media industry. Critical reflection of manipulative communication techniques puts spin phenomenon in historical perspective and traces its practical use in today's social communica...

  8. Magnetic structures, phase diagram and spin waves of magneto-electric LiNiPO4

    DEFF Research Database (Denmark)

    Jensen, Thomas Bagger Stibius

    2007-01-01

    LiNiPO4 is a magneto-electric material, having co-existing antiferromagnetic and ferroelectric phases when suitable magnetic fields are applied at low temperatures. Such systems have received growing interest in recent years, but the nature of the magneticelectric couplings is yet to be fully...... understand. Hopefully, studying LiNiPO4 will shed further light on the subject, especially since the crystal structure of LiNiPO4 is rather simple compared to most relevant multiferroic materials. Although the study of the magnetic-electric couplings is of main interest to the many scientists guiding me...... through the last three years, it is not the primary subject of this thesis. The objective of the phD project has been to provide groundwork that may be beneficiary to future studies of LiNiPO4. More specifically, we have mapped out the magnetic HT phase diagram with magnetic fields below 14.7 T applied...

  9. Decoupling of the Leading Order DGLAP Evolution Equation with Spin Dependent Structure Functions

    Science.gov (United States)

    Azadbakht, F. Teimoury; Boroun, G. R.

    2018-02-01

    We propose an analytical solution for DGLAP evolution equations with polarized splitting functions at the Leading Order (LO) approximation based on the Laplace transform method. It is shown that the DGLAP evolution equations can be decoupled completely into two second order differential equations which then are solved analytically by using the initial conditions δ FS(x,Q2)=F[partial δ FS0(x), δ FS0(x)] and {δ G}(x,Q2)=G[partial δ G0(x), δ G0(x)]. We used this method to obtain the polarized structure function of the proton as well as the polarized gluon distribution function inside the proton and compared the numerical results with experimental data of COMPASS, HERMES, and AAC'08 Collaborations. It was found that there is a good agreement between our predictions and the experiments.

  10. The structure and spin dynamics of lanthanide-bearing silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, A.J.G.; Loong, C.K.; Wagner, J.

    1993-10-01

    Structures of 3Na{sub 2}O{center_dot}R{sub 2}O{sub 3}{center_dot}6SiO{sub 2} (R = Nd, Yb and Lu) glasses were studied by time-of-flight neutron diffraction. Average Si-O and O-O nearest-neighbor coordination is found to be similar to SiO{sub 4} tetrahedral units in vitreous SiO{sub 2} and other silicate glasses. The RE ions coordinate with no more than 7 nearest-neighbor oxygen atoms. The dynamic and static response of these glasses and their isochemical crystalline analogs have been investigated by inelastic neutron scattering and magnetic susceptibility measurements. The magnetic excitation spectra were analyzed by a ligand-field model using a method of descending symmetry. Correlation between short-range atomic order in a network glass and magnetic interactions of the RE ions with the local environment is discussed.

  11. Estimating ladder fuels: a new approach combining field photography with LiDAR

    Science.gov (United States)

    Heather Kramer; Brandon Collins; Frank Lake; Marek Jakubowski; Scott Stephens; Maggi Kelly

    2016-01-01

    Forests historically associated with frequent fire have changed dramatically due to fire suppression and past harvesting over the last century. The buildup of ladder fuels, which carry fire from the surface of the forest floor to tree crowns, is one of the critical changes, and it has contributed to uncharacteristically large and severe fires. The abundance of ladder...

  12. 29 CFR 1910.29 - Manually propelled mobile ladder stands and scaffolds (towers).

    Science.gov (United States)

    2010-07-01

    .... (stress grade) construction grade lumber or equivalent. (vi) All scaffold work levels 10 feet or higher..., construction, and use of mobile work platforms (including ladder stands but not including aerial ladders) and... the use of mobile work platforms and towers. (2) Working loads. (i) Work platforms and scaffolds shall...

  13. Dissipation, Voltage Profile and Levy Dragon in a Special Ladder Network

    Science.gov (United States)

    Ucak, C.

    2009-01-01

    A ladder network constructed by an elementary two-terminal network consisting of a parallel resistor-inductor block in series with a parallel resistor-capacitor block sometimes is said to have a non-dispersive dissipative response. This special ladder network is created iteratively by replacing the elementary two-terminal network in place of the…

  14. Passage and behaviour of cultured Lake Sturgeon in a prototype side-baffle fish ladder: I. Ladder hydraulics and fish ascent

    Science.gov (United States)

    Kynard, B.; Pugh, D.; Parker, T.

    2011-01-01

    Research and development of a fish ladder for sturgeons requires understanding ladder hydraulics and sturgeon behaviour in the ladder to insure the ladder is safe and provides effective passage. After years of research and development, we designed and constructed a full-scale prototype side-baffle ladder inside a spiral flume (38.3m long??1m wide??1m high) on a 6% (1:16.5) slope with a 1.92-m rise in elevation (bottom to top) to test use by sturgeons. Twenty-eight triangular side baffles, each extending part way across the flume, alternated from inside wall to outside wall down the ladder creating two major flow habitats: a continuous, sinusoidal flow down the ladder through the vertical openings of side-baffles and an eddy below each side baffle. Ascent and behaviour was observed on 22 cultured Lake Sturgeon=LS (Acipenser fulvescens) repeatedly tested in groups as juveniles (as small as 105.1cm TL, mean) or as adults (mean TL, 118cm) during four periods (fall 2002 and 2003; spring 2003 and 2007). Percent of juveniles entering the ladder that ascended to the top was greater in spring (72.7%) than in fall (40.9-45.5%) and 90.9% of 11 adults, which ascended as juveniles, ascended to the top. Six LS (27.3%) never swam to the top and seven (31.8%) swam to the top in all tests, indicating great variability among individuals for ascent drive. Some LS swam directly to the top in <1min, but most rested in an eddy during ascent. Juveniles swimming through outside wall baffle slots (mean velocity, 1.2ms-1) swam at 1.8-2.2body lengthss-1 and 3.2-3.3tail beatss-1, either at or approaching prolonged swimming speed. The side-baffle ladder was stream-like and provided key factors for a sturgeon ladder: a continuous flow and no full cross-channel walls, abundant eddies for resting, an acceptable water depth, and a water velocity fish could ascend swimming 2bls-1. A side-baffle ladder passes LS and other moderate-swimming fishes. ?? 2011 Blackwell Verlag, Berlin.

  15. Resonant Tunneling Spin Pump

    Science.gov (United States)

    Ting, David Z.

    2007-01-01

    The resonant tunneling spin pump is a proposed semiconductor device that would generate spin-polarized electron currents. The resonant tunneling spin pump would be a purely electrical device in the sense that it would not contain any magnetic material and would not rely on an applied magnetic field. Also, unlike prior sources of spin-polarized electron currents, the proposed device would not depend on a source of circularly polarized light. The proposed semiconductor electron-spin filters would exploit the Rashba effect, which can induce energy splitting in what would otherwise be degenerate quantum states, caused by a spin-orbit interaction in conjunction with a structural-inversion asymmetry in the presence of interfacial electric fields in a semiconductor heterostructure. The magnitude of the energy split is proportional to the electron wave number. Theoretical studies have suggested the possibility of devices in which electron energy states would be split by the Rashba effect and spin-polarized currents would be extracted by resonant quantum-mechanical tunneling.

  16. Off-Yrast low-spin structure of deformed nuclei at mass number A∼150

    Energy Technology Data Exchange (ETDEWEB)

    Krugmann, Andreas

    2014-07-14

    -spinflip parts of the cross section has been done. Here, for the first time, the Pygmy Dipole Resonance (PDR) has been identified in the heavy deformed nucleus {sup 154}Sm that appears as a double-hump structure in the E1 response. A possible interpretation of this double-hump structure in terms of a deformation splitting analogously to the Giant Dipole Resonance (GDR) has been given. In case of the spinflip cross section, a broad distribution in the excitation energy range between 6 and 12 MeV has been observed. The distribution and the extracted sum strength are in good accordance with previous experiments.

  17. Output-only cyclo-stationary linear-parameter time-varying stochastic subspace identification method for rotating machinery and spinning structures

    Science.gov (United States)

    Velazquez, Antonio; Swartz, R. Andrew

    2015-02-01

    Economical maintenance and operation are critical issues for rotating machinery and spinning structures containing blade elements, especially large slender dynamic beams (e.g., wind turbines). Structural health monitoring systems represent promising instruments to assure reliability and good performance from the dynamics of the mechanical systems. However, such devices have not been completely perfected for spinning structures. These sensing technologies are typically informed by both mechanistic models coupled with data-driven identification techniques in the time and/or frequency domain. Frequency response functions are popular but are difficult to realize autonomously for structures of higher order, especially when overlapping frequency content is present. Instead, time-domain techniques have shown to possess powerful advantages from a practical point of view (i.e. low-order computational effort suitable for real-time or embedded algorithms) and also are more suitable to differentiate closely-related modes. Customarily, time-varying effects are often neglected or dismissed to simplify this analysis, but such cannot be the case for sinusoidally loaded structures containing spinning multi-bodies. A more complex scenario is constituted when dealing with both periodic mechanisms responsible for the vibration shaft of the rotor-blade system and the interaction of the supporting substructure. Transformations of the cyclic effects on the vibrational data can be applied to isolate inertial quantities that are different from rotation-generated forces that are typically non-stationary in nature. After applying these transformations, structural identification can be carried out by stationary techniques via data-correlated eigensystem realizations. In this paper, an exploration of a periodic stationary or cyclo-stationary subspace identification technique is presented here for spinning multi-blade systems by means of a modified Eigensystem Realization Algorithm (ERA) via

  18. Micromagnetic analysis of spin-reorientation transitions. The role of magnetic domain structure

    Energy Technology Data Exchange (ETDEWEB)

    Skokov, Konstantin P., E-mail: skokov_k_p@mail.ru [Tver State University, Tver 170100 (Russian Federation); Physics Department, Chelyabinsk State University, Chelyabinsk 454001 (Russian Federation); Pastushenkov, Yury G., E-mail: yupast@mail.ru [Tver State University, Tver 170100 (Russian Federation); Taskaev, Sergey V., E-mail: tsv@csu.ru [Physics Department, Chelyabinsk State University, Chelyabinsk 454001 (Russian Federation); National University of Science and Technology “MISiS”, Moscow 119049 (Russian Federation); Rodionova, Valeria V., E-mail: valeriarodionova@gmail.com [National University of Science and Technology “MISiS”, Moscow 119049 (Russian Federation); Immanuel Kant Baltic Federal University, Kaliningrad 236041 (Russian Federation)

    2015-12-01

    A method for calculating micromagnetic state of ferro- or ferrimagnetic single-crystals based on the Néel's method of phases is proposed. The standard Néel technique requires different approaches to calculation of micromagnetic state of samples with different anisotropy types. Furthermore, this technique cannot be used to calculate magnetization curves of materials with a complex anisotropy type, in which the first-order magnetization process (FOMP) occurs. On the contrary, the technique proposed in the present work makes it possible to calculate micromagnetic state of a sample within one unified approach. This technique has no limitations in terms of the anisotropy type as well. In case of the FOMP, the simulation methods that we used show results different from conventional calculation methods. The reason is that the conventional methods imply coherent rotation of magnetization in single domain particle (so-called Stoner–Wohlfarth model). We explain this discrepancy by the fact that a magnetic domain structure appears in the region of the FOMP. In the present work we show that magnetization processes do not occur in a jump under the FOMP but gradually pass though nucleation and new high-field phase growing, which substitutes for the low-field phase.

  19. Micromagnetic analysis of spin-reorientation transitions. The role of magnetic domain structure

    International Nuclear Information System (INIS)

    Skokov, Konstantin P.; Pastushenkov, Yury G.; Taskaev, Sergey V.; Rodionova, Valeria V.

    2015-01-01

    A method for calculating micromagnetic state of ferro- or ferrimagnetic single-crystals based on the Néel's method of phases is proposed. The standard Néel technique requires different approaches to calculation of micromagnetic state of samples with different anisotropy types. Furthermore, this technique cannot be used to calculate magnetization curves of materials with a complex anisotropy type, in which the first-order magnetization process (FOMP) occurs. On the contrary, the technique proposed in the present work makes it possible to calculate micromagnetic state of a sample within one unified approach. This technique has no limitations in terms of the anisotropy type as well. In case of the FOMP, the simulation methods that we used show results different from conventional calculation methods. The reason is that the conventional methods imply coherent rotation of magnetization in single domain particle (so-called Stoner–Wohlfarth model). We explain this discrepancy by the fact that a magnetic domain structure appears in the region of the FOMP. In the present work we show that magnetization processes do not occur in a jump under the FOMP but gradually pass though nucleation and new high-field phase growing, which substitutes for the low-field phase.

  20. Spin Switching via Quantum Dot Spin Valves

    Science.gov (United States)

    Gergs, N. M.; Bender, S. A.; Duine, R. A.; Schuricht, D.

    2018-01-01

    We develop a theory for spin transport and magnetization dynamics in a quantum dot spin valve, i.e., two magnetic reservoirs coupled to a quantum dot. Our theory is able to take into account effects of strong correlations. We demonstrate that, as a result of these strong correlations, the dot gate voltage enables control over the current-induced torques on the magnets and, in particular, enables voltage-controlled magnetic switching. The electrical resistance of the structure can be used to read out the magnetic state. Our model may be realized by a number of experimental systems, including magnetic scanning-tunneling microscope tips and artificial quantum dot systems.

  1. Perturbative QCD predictions for the small x behaviour of unpolarized and polarized deep inelastic scattering structure functions

    International Nuclear Information System (INIS)

    Kwiecinski, J.

    1996-01-01

    The perturbative QCD predictions for the small x behaviour of the nucleon structure functions F 2L (x,Q 2 ) and g 1 (x,Q 2 ) are summarized. The importance of the double logarithmic terms for the small x behaviour of the spin structure function g 1 (x,Q 2 ) is emphasized. These terms correspond to the contributions containing the leading powers of α s ln 2 (1/x) at each order of the perturbative expansion. In the non-singlet case they can be approximately accounted for by the ladder diagrams with quark (antiquark) exchange. We solve the corresponding integral equation with the running coupling effects taken into account and present estimate of the effective slope controlling the small x behaviour of the non-singlet spin structure function g 1 (x,Q 2 ) of a nucleon. (author)

  2. Investigation on Spin Dependent Transport Properties of Core-Shell Structural Fe3O4/ZnS Nanocomposites for Spintronic Application

    Science.gov (United States)

    Liu, Er; Yuan, Honglei; Kou, Zhaoxia; Wu, Xiumei; Xu, Qingyu; Zhai, Ya; Sui, Yunxia; You, Biao; Du, Jun; Zhai, Hongru

    2015-01-01

    The core-shell structural Fe3O4/ZnS nanocomposites with controllable shell thickness were well-fabricated via seed-mediate growth method. Structural and morphological characterizations reveal the direct deposition of crystalline II-VI compound semiconductor ZnS shell layer on Fe3O4 particles. Spin dependent electrical transport is studied on Fe3O4/ZnS nanocomposites with different shell thickness, and a large magnetoresistance (MR) ratio is observed under the magnetic field of 1.0 T at room temperature and 100 K for the compacted sample by Fe3O4/ZnS nanocomposites, which is 50% larger than that of sample with pure Fe3O4 particles, indicating that the enhanced MR is contributed from the spin injection between Fe3O4 and ZnS layer. PMID:26053888

  3. A Search for Higher Twist Effects in the Neutron Spin Structure Function gn2(x,Q2)

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Kevin [College of William and Mary, Williamsburg, VA (United States)

    2003-08-01

    Jefferson Lab experiment E97-103 measured the spin structure function gn2(x,Q2) from a Q2 of 0.58 to 1.36 with a nearly constant x of 0.2. Combining this data with a fit to the world gn1 data, the size of higher twist contributions to the spin structure functions can be extracted using the Wandzura-Wilczek relation. These higher twist contributions result from quark-gluon correlations and are expected to be larger as Q2 decreases. This experiment was performed in Hall A with a longitudinally polarized electron beam and a high density polarized 3He target. The physics motivation and an overview of the experiment will be presented.

  4. ^51V NMR Study of the Magnetic Structure of the Frustrated Zig-Zag Spin-1 Chain Compound CaV2O4

    Science.gov (United States)

    Zong, X.; Suh, B. J.; Niazi, A.; Johnston, D. C.

    2007-03-01

    ^51V NMR measurements have been performed on a single crystal of orthorhombic (at room temperature) CaV2O4 in zero applied magnetic field and with a small perturbing field up to H = 2 T, at temperatures well below the N'eel temperature TN= 78 K@. The c-axis is parallel to the chains. At H = 0, a broad ^51V NMR spectrum with a peak at 237 MHz was observed. The effective local hyperfine field Heff = 21.2 T corresponding to the peak frequency 237 MHz is in good agreement with expectation for the V^3+ S = 1 spin state. In Hc, the spectrum splits into two parts that are equally separated from the peak position at zero field. The separation of the parts depends strongly both on the magnitude and direction of H with respect to the crystal axes. Our NMR results are consistent with a collinear antiferromagnetic spin structure with the spin direction along the b-axis, which together with the magnetization data suggest that the antiferromagnetic long-range order arises from an order-from-disorder mechanism. We also present the temperature and orientation dependence of the spin-lattice relaxation rate 1/T1.

  5. Reorientation of the diagonal double-stripe spin structure at Fe1+yTe bulk and thin-film surfaces

    Science.gov (United States)

    Hänke, Torben; Singh, Udai Raj; Cornils, Lasse; Manna, Sujit; Kamlapure, Anand; Bremholm, Martin; Hedegaard, Ellen Marie Jensen; Iversen, Bo Brummerstedt; Hofmann, Philip; Hu, Jin; Mao, Zhiqiang; Wiebe, Jens; Wiesendanger, Roland

    2017-01-01

    Establishing the relation between ubiquitous antiferromagnetism in the parent compounds of unconventional superconductors and their superconducting phase is important for understanding the complex physics in these materials. Going from bulk systems to thin films additionally affects their phase diagram. For Fe1+yTe, the parent compound of Fe1+ySe1-xTex superconductors, bulk-sensitive neutron diffraction revealed an in-plane oriented diagonal double-stripe antiferromagnetic spin structure. Here we show by spin-resolved scanning tunnelling microscopy that the spin direction at the surfaces of bulk Fe1+yTe and thin films grown on the topological insulator Bi2Te3 is canted out of the high-symmetry directions of the surface unit cell resulting in a perpendicular spin component, keeping the diagonal double-stripe order. As the magnetism of the Fe d-orbitals is intertwined with the superconducting pairing in Fe-based materials, our results imply that the superconducting properties at the surface of the related superconducting compounds might be different from the bulk.

  6. Topological phases in frustrated synthetic ladders with an odd number of legs

    Science.gov (United States)

    Barbarino, Simone; Dalmonte, Marcello; Fazio, Rosario; Santoro, Giuseppe E.

    2018-01-01

    The realization of the Hofstadter model in a strongly anisotropic ladder geometry has now become possible in one-dimensional optical lattices with a synthetic dimension. In this work, we show how the Hofstadter Hamiltonian in such ladder configurations hosts a topological phase of matter which is radically different from its two-dimensional counterpart. This topological phase stems directly from the hybrid nature of the ladder geometry and is protected by a properly defined inversion symmetry. We start our analysis by considering the paradigmatic case of a three-leg ladder which supports a topological phase exhibiting the typical features of topological states in one dimension: robust fermionic edge modes, a degenerate entanglement spectrum, and a nonzero Zak phase; then, we generalize our findings—addressable in the state-of-the-art cold-atom experiments—to ladders with a higher number of legs.

  7. Assembly procedure for the silicon pixel ladder for PHENIX silicon vertex tracker

    International Nuclear Information System (INIS)

    Onuki, Y.; Akiba, Y.; En'yo, H.; Fujiwara, K.; Haki, Y.; Hashimoto, K.; Ichimiya, R.; Kasai, M.; Kawashima, M.; Kurita, K.; Kurosawa, M.; Mannel, E.J.; Nakano, K.; Pak, R.; Sekimoto, M.; Sondheim, W.E.; Taketani, A.; Togawa, M.; Yamamoto, Y.

    2009-01-01

    The silicon vertex tracker (VTX) will be installed in the summer of 2010 to enhance the physics capabilities of the Pioneering High Energy Nuclear Interaction eXperiment (PHENIX) experiment at Brookhaven National Laboratory. The VTX consists of two types of silicon detectors: a pixel detector and a strip detector. The pixel detector consists of 30 pixel ladders placed on the two inner cylindrical layers of the VTX. The ladders are required to be assembled with high precision, however, they should be assembled in both cost and time efficient manner. We have developed an assembly bench for the ladder with several assembly fixtures and a quality assurance (Q/A) system using a 3D measurement machine. We have also developed an assembly procedure for the ladder, including a method for dispensing adhesive uniformly and encapsulation of bonding wires. The developed procedures were adopted in the assembly of the first pixel ladder and satisfy the requirements.

  8. Theoretical investigations of the spin-Hamiltonian parameters and local structural distortion of Fe(3+): ZnAl2O4 crystals.

    Science.gov (United States)

    Yang, Zi-Yuan

    2014-10-15

    The relations between the spin-Hamiltonian (SH) parameters and the structural parameters of the Fe(3+) ions in Fe(3+): ZnAl2O4 crystals have been established by means of the microscopic spin Hamiltonian theory and the superposition model (SPM). On the basis of this, the local structure distortion, the second-order zero-field splitting (ZFS) parameter D, the fourth-order ZFS parameter (a-F), and the Zeeman g-factors g factors: g//, g⊥, and Δg(=g//-g⊥) for Fe(3+) ions in Fe(3+): ZnAl2O4 crystals, for the first time taking into account the electronic magnetic interactions, i.e. the spin-spin (SS), the spin-other-orbit (SOO), and the orbit-orbit (OO) interactions, besides the well-known spin-orbit (SO) interaction, are theoretically investigated using complete diagonalization method (CDM). This investigation reveals that the local structure distortion effect plays an important role in explaining the spectroscopic properties of Fe(3+) ions in Fe(3+): ZnAl2O4 crystals. The theoretical second-order ZFS parameter D, the fourth-order ZFS parameter (a-F), and the Zeeman g-factors: g//, g⊥, and Δg of the ground state for Fe(3+) ion in Fe(3+): ZnAl2O4 crystals yield a good agreement with experiment findings by taking into account the lattice distortions: ΔR=0.0191nm and Δθ=0.076°. In conclusion, our research shows that there is a slight local structure distortion for Fe(3+) ions in Fe(3+): ZnAl2O4 crystals, but the site of Fe(3+) still retains D3d symmetry. On the other hand, it is found for Fe(3+) ions in Fe(3+): ZnAl2O4 crystals that the SO mechanism is the most important one, whereas the contributions to the SH parameters from other four mechanisms, including the SS, SOO, OO, and SO∼SS∼SOO∼OO mechanisms are not appreciable, especially for the ZFS parameter D. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Near-Surface Structural Phase Transition of SrTiO3 Studied with Zero-Field β-Detected Nuclear Spin Relaxation and Resonance

    Science.gov (United States)

    Salman, Z.; Kiefl, R. F.; Chow, K. H.; Hossain, M. D.; Keeler, T. A.; Kreitzman, S. R.; Levy, C. D. P.; Miller, R. I.; Parolin, T. J.; Pearson, M. R.; Saadaoui, H.; Schultz, J. D.; Smadella, M.; Wang, D.; Macfarlane, W. A.

    2006-04-01

    We demonstrate that zero-field β-detected nuclear quadrupole resonance and spin relaxation of low energy Li8 can be used as a sensitive local probe of structural phase transitions near a surface. We find that the transition near the surface of a SrTiO3 single crystal occurs at Tc˜150K, i.e., ˜45K higher than Tcbulk, and that the tetragonal domains formed below Tc are randomly oriented.

  10. Synchrotron radiation structure analyses of the light-induced radical pair of a hexaarylbiimidazolyl derivative. Origin of the spin-multiplicity change

    CERN Document Server

    Kawano, M; Matsubara, K; Imabayashi, H; Mitsumi, M; Toriumi, K; Ohashi, Y

    2002-01-01

    In situ synchrotron radiation structure analyses of a light-induced radical pair from o-Cl-HABI were performed by using an X-ray vacuum camera at 23-70K at the BL02B1 station of SPring-8. The combined results of X-ray analysis with theoretical calculation, IR, and UV-vis spectroscopy reveal that a slight conformational change of the radical pair causes the drastic spin-multiplicity change during 2-140K. (author)

  11. Movements of adult Atlantic salmon in relation to a hydroelectric dam and fish ladder

    International Nuclear Information System (INIS)

    Gowans, A.R.D.; Priede, I.G.

    1999-01-01

    The movements of adult Atlantic salmon were recorded as they approached, entered and ascended the pool-and-orifice fish ladder at Pitlochry Dam, Scotland. Thirty-nine returning salmon were captured in the River Tummel by rod-and-line angling, radio-tagged and released near where they were caught. The subsequent movements of each fish were then monitored. An electronic fish counter collected additional data on movements of untagged fish past a fixed point in the ladder. Of the 39 fish that were radio-tagged, 29 individuals were recorded approaching and ascending the ladder. The remaining fish either did not approach the dam (three fish), approached the dam after detailed tracking had ended (two fish), were recaptured by anglers (three fish), or the radio tags failed (two fish). Salmon released earlier in the year delayed longer before first approaching the dam. Delays between first approaching the dam and ascent of the ladder were greater for fish that approached the dam earlier. The majority of salmon visited the ladder entrance more than once (maximum 10 visits) before ascending. Having entered, all but four salmon ascended the fish ladder successfully on their first attempt. The four individuals that failed to do so succeeded on their second attempt. The rate at which salmon ascended the ladder was related directly to temperature. The shortest ascent time of a radio-tagged salmon was 5.25 h. Movements of eight of 11 tagged fish through the ladder ceased with the onset of darkness but continued on the following morning. No radio-tagged fish entered the ladder at temperatures below 9 o C. Similarly, few untagged fish were recorded ascending the ladder by the electronic fish counter at water temperatures below 8.5 o C. Records from the fish counter indicated that 92% of upstream movements were made during daylight. (author)

  12. Photon-assisted and spin-dependent shot noise in magnetic-field tunable ZnSe/Zn_1_−_x Mn_x Se structures

    International Nuclear Information System (INIS)

    Li Chun-Lei; Lv Yuan; Guo Yong; Wang Xiao-Ming

    2017-01-01

    We have investigated the photon-assisted shot noise properties in the magnetic field tunable heterostructures. Transport properties of the model structure are strongly dependent on the oscillatory field and the magnetic field. In this structure, electrons can absorb or emit one or multi-photons to reach the quasi-bound state. As a result, the transmission properties are affected considerably by photon-assisted tunneling and these features cause the nontrivial variations in the shot noise and Fano factor. It is found that the shot noise becomes spin-dependent and can be modulated not only by the magnetic field, but also by the oscillatory field. Both the spin-up and spin-down components of the shot noise can be greatly suppressed by the magnetic field, and can also be drastically enhanced by the harmonically driven field. Furthermore, with increasing external magnetic field, it is important to note that the enhanced intensity is decreased, even suppressed. These results suggest another method to suppress the shot noise via modulating the oscillatory field at a diluted-magnetic semiconductors/semiconductor structure. (paper)

  13. Spin glasses

    CERN Document Server

    Bovier, Anton

    2007-01-01

    Spin glass theory is going through a stunning period of progress while finding exciting new applications in areas beyond theoretical physics, in particular in combinatorics and computer science. This collection of state-of-the-art review papers written by leading experts in the field covers the topic from a wide variety of angles. The topics covered are mean field spin glasses, including a pedagogical account of Talagrand's proof of the Parisi solution, short range spin glasses, emphasizing the open problem of the relevance of the mean-field theory for lattice models, and the dynamics of spin glasses, in particular the problem of ageing in mean field models. The book will serve as a concise introduction to the state of the art of spin glass theory, usefull to both graduate students and young researchers, as well as to anyone curious to know what is going on in this exciting area of mathematical physics.

  14. Surface Acoustic Bloch Oscillations, the Wannier-Stark Ladder, and Landau-Zener Tunneling in a Solid

    Science.gov (United States)

    de Lima, M. M., Jr.; Kosevich, Yu. A.; Santos, P. V.; Cantarero, A.

    2010-04-01

    We present the experimental observation of Bloch oscillations, the Wannier-Stark ladder, and Landau-Zener tunneling of surface acoustic waves in perturbed grating structures on a solid substrate. A model providing a quantitative description of our experimental observations, including multiple Landau-Zener transitions of the anticrossed surface acoustic Wannier-Stark states, is developed. The use of a planar geometry for the realization of the Bloch oscillations and Landau-Zener tunneling allows a direct access to the elastic field distribution. The vertical surface displacement has been measured by interferometry.

  15. QCD SPIN PHYSICS IN HADRONIC INTERACTIONS.

    Energy Technology Data Exchange (ETDEWEB)

    VOGELSANG,W.

    2007-06-19

    We discuss spin phenomena in high-energy hadronic scattering, with a particular emphasis on the spin physics program now underway at the first polarized proton-proton collider, RHIC. Experiments at RHIC unravel the spin structure of the nucleon in new ways. Prime goals are to determine the contribution of gluon spins to the proton spin, to elucidate the flavor structure of quark and antiquark polarizations in the nucleon, and to help clarify the origin of transverse-spin phenomena in QCD. These lectures describe some aspects of this program and of the associated physics.

  16. A Precision Measurement of the Spin Structure Functions f^p_1 and g^g_1

    Energy Technology Data Exchange (ETDEWEB)

    Toole, T.

    2004-12-13

    In Experiment E155 at the Stanford Linear Accelerator Center, the spin dependent structure function g{sub 1}(x,Q{sup 2}) was measured for both the proton and deuteron. This was accomplished by scattering 48.3 GeV highly polarized electrons (0.813 {+-} 0.020) off polarized {sup 15}NH{sub 3} (proton) and {sup 6}LiD (deuteron) targets. Data were collected in March and April of 1997 using three fixed angle, momentum analyzing spectrometers centered at 2.75{sup o}, 5.5{sup o}, and 10.5{sup o}. This enabled a kinematic coverage of 0.01 < x < 0.9 and 1 GeV{sup 2} < Q{sup 2} < 40 GeV{sup 2}. At an average Q{sup 2} of 5 GeV{sup 2}, the integrals in the measured region were f{sub 0.014}{sup 0.9}g{sub 1}(x)dx = 0.119 {+-} 0.002(stat.) {+-} 0.009(syst.) for the proton and 0.043 {+-} 0.003(stat.) {+-} 0.003(syst.) for the deuteron. Using a perturbative QCD analysis which included a global data set, the results were found to be consistent with the Bjorken Sum Rule. Asymmetry measurements also were made using photoproduced hadrons. Data were collected concurrently with the g{sub 1} data. For the proton, the asymmetries were small and non-zero. The deuteron measurements were consistent with zero.

  17. Significant manipulation of output performance of a bridge-structured spin valve magnetoresistance sensor via an electric field

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yue; Yan, Baiqian; Ou-Yang, Jun; Zhu, Benpeng; Chen, Shi; Yang, Xiaofei, E-mail: hust-yangxiaofei@163.com [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wang, Xianghao [School of Information Engineering, Wuhan University of Technology, Wuhan 430070 (China)

    2016-01-28

    Through principles of spin-valve giant magnetoresistance (SV-GMR) effect and its application in magnetic sensors, we have investigated electric-field control of the output performance of a bridge-structured Co/Cu/NiFe/IrMn SV-GMR sensor on a PZN-PT piezoelectric substrate using the micro-magnetic simulation. We centered on the influence of the variation of uniaxial magnetic anisotropy constant (K) of Co on the output of the bridge, and K was manipulated via the stress of Co, which is generated from the strain of a piezoelectric substrate under an electric field. The results indicate that when K varies between 2 × 10{sup 4 }J/m{sup 3} and 10 × 10{sup 4 }J/m{sup 3}, the output performance can be significantly manipulated: The linear range alters from between −330 Oe and 330 Oe to between −650 Oe and 650 Oe, and the sensitivity is tuned by almost 7 times, making it possible to measure magnetic fields with very different ranges. According to the converse piezoelectric effect, we have found that this variation of K can be realized by applying an electric field with the magnitude of about 2–20 kV/cm on a PZN-PT piezoelectric substrate, which is realistic in application. This result means that electric-control of SV-GMR effect has potential application in developing SV-GMR sensors with improved performance.

  18. Significant manipulation of output performance of a bridge-structured spin valve magnetoresistance sensor via an electric field

    International Nuclear Information System (INIS)

    Zhang, Yue; Yan, Baiqian; Ou-Yang, Jun; Zhu, Benpeng; Chen, Shi; Yang, Xiaofei; Wang, Xianghao

    2016-01-01

    Through principles of spin-valve giant magnetoresistance (SV-GMR) effect and its application in magnetic sensors, we have investigated electric-field control of the output performance of a bridge-structured Co/Cu/NiFe/IrMn SV-GMR sensor on a PZN-PT piezoelectric substrate using the micro-magnetic simulation. We centered on the influence of the variation of uniaxial magnetic anisotropy constant (K) of Co on the output of the bridge, and K was manipulated via the stress of Co, which is generated from the strain of a piezoelectric substrate under an electric field. The results indicate that when K varies between 2 × 10 4  J/m 3 and 10 × 10 4  J/m 3 , the output performance can be significantly manipulated: The linear range alters from between −330 Oe and 330 Oe to between −650 Oe and 650 Oe, and the sensitivity is tuned by almost 7 times, making it possible to measure magnetic fields with very different ranges. According to the converse piezoelectric effect, we have found that this variation of K can be realized by applying an electric field with the magnitude of about 2–20 kV/cm on a PZN-PT piezoelectric substrate, which is realistic in application. This result means that electric-control of SV-GMR effect has potential application in developing SV-GMR sensors with improved performance

  19. Effect of Cu2 + substitution in spin-orbit coupled Sr2Ir1 -xCuxO4 : Structure, magnetism, and electronic properties

    Science.gov (United States)

    Bhatti, Imtiaz Noor; Dhaka, R. S.; Pramanik, A. K.

    2017-10-01

    Sr2Ir O4 is an extensively studied spin-orbit coupling induced insulator with antiferromagnetic ground state. The delicate balance between competing energy scales plays a crucial role for its low-temperature phase and the route of chemical substitution has often been used to tune these different energy scales. Here, we report an evolution of structural, magnetic, and electronic properties in doped Sr2Ir1 -xCuxO4 (x ≤0.2 ). The substitution of Cu2 + (3 d9 ) for Ir4 + (5 d5 ) acts for electron doping, though it tunes the related parameters such as spin-orbit coupling, electron correlation, and Ir charge state. Moreover, both Ir4 + and Cu2 + has single unpaired spin, though it occupies different d orbitals. With Cu substitution, the system retains its original structural symmetry but the structural parameters show systematic changes. X-ray photoemission spectroscopy measurements show that Ir4 + equivalently converts to Ir5 + and a significant enhancement in the density of states has been observed at the Fermi level due to the contribution from the Cu 3 d orbitals, which supports the observed decrease in the resistivity with Cu substitution. While the long-range magnetic ordering is much weakened and the highest-doped sample shows almost paramagneticlike behavior, the overall system remains insulator. Analysis of the resistivity data shows a mode of charge conduction in the whole series follows a two-dimensional variable-range-hopping model, but the range of validity varies with temperature. The whole series of samples exhibits negative magnetoresistance at low temperature, which is considered to be a signature of a weak-localization effect in a spin-orbit coupled system, and its evolution with Cu appears to follow the variation of resistivity with x .

  20. The fast spin of near-Earth asteroid (455213) 2001 OE84, revisited after 14 years: Constraints on internal structure

    Science.gov (United States)

    Polishook, D.; Moskovitz, N.; Thirouin, A.; Bosh, A.; Levine, S.; Zuluaga, C.; Tegler, S. C.; Aharonson, O.

    2017-11-01

    At a mean diameter of ∼650 m, the near-Earth asteroid (455213) 2001 OE84 (OE84 for short) has a rapid rotation period of 0.486542 ± 0.000002 h, which is uncommon for asteroids larger than ∼200 m. We revisited OE84 14 years after it was first, and last, observed by Pravec et al. (2002) in order to measure again its spin rate and to search for changes. We have confirmed the rapid rotation and, by fitting the photometric data from 2001 and 2016 using the lightcurve inversion technique, we determined a retrograde sense of rotation, with the spin axis close to the ecliptic south pole; an oblate shape model of a / b = 1.32 ± 0.04 and b / c = 1.8 ± 0.2 ; and no change in spin rate between 2001 and 2016. Using these parameters we constrained the body's internal strength, and found that current estimations of asteroid cohesion (up to ∼80 Pa) are insufficient to maintain an intact rubble pile at the measured spin rate of OE84. Therefore, we argue that a monolithic asteroid, that can rotate at the rate of OE84 without shedding mass and without slowing down its spin rate, is the most plausible for OE84, and we give constraints on its age, since the time it was liberated from its parent body, between 2 - 10 million years.

  1. Side chain effect on electronic structure of spin-coated films of [6,6]-phenyl-C61-butyric acid methyl ester and its bis-adduct

    International Nuclear Information System (INIS)

    Akaike, Kouki; Kanai, Kaname; Ouchi, Yukio; Seki, Kazuhiko

    2013-01-01

    Highlights: ► Electronic structure of spin-coated films of PCBM and bis-PCBM was investigated. ► Ionization energy and electron affinity of bis-PCBM are smaller than those of PCBM. ► Electron donation from the side chain to C 60 -backbone raises the HOMO and LUMO. ► Open circuit voltages of PCBM-based solar cells relates to electron affinities. - Abstract: We investigated the electronic structure of spin-coated films of two soluble fullerenes; [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) and its bis-adduct (bis-PCBM) using ultraviolet photoelectron spectroscopy, inverse photoemission spectroscopy and molecular orbital calculations. The ionization energy and electron affinity of spin-coated films of bis-PCBM were determined to be 6.01 eV and 3.4 eV, respectively. Analysis of electron density suggested the stronger electron donation from the two side chains to fullerene-backbone in a bis-PCBM molecule, compared with PCBM. The electron donation raises the energies of the frontier orbitals of bis-PCBM, which mainly consist of π-orbitals of fullerene-backbone. As a result, the ionization energy and electron affinity of bis-PCBM are smaller than those of PCBM. Moreover, we also concluded that the larger open circuit voltage observed for bis-PCBM based organic photovoltaics was explained by the higher-lying unoccupied molecular orbital of bis-PCBM

  2. Studies on rheological, structural, optical, electrical and surface properties of LiMn2O4 thin films by varied spin rates

    Directory of Open Access Journals (Sweden)

    Balakrishnan T.

    2017-10-01

    Full Text Available LiMn2O4 thin films prepared by cost-effective spin coating method using optimized coating conditions are reported. Spin rate was varied and spin rate dependent properties were studied. Prepared films were characterized for their structural, morphological and optical properties. X-ray diffraction study of LiMn2O4 thin films confirmed the cubic spinel structure with the preferred orientation along (1 1 1 plane. Optical absorption studies showed band gap energy of 3.02 eV for the grown LiMn2O4 films. FT-IR bands assigned to asymmetric stretching modes of MnO6 group were located around 623 cm-1 and 514 cm-1 for the LiMn2O4 thin films. The weak band observed at 437 cm-1 was attributed to the LiO4 tetrahedra. The films showed high conductivity value 0.79 S/cm indicating the generation of effective network of the film for enhanced charge transport. AFM micrographs of the LiMn2O4 films deposited at 3000 rpm and 3500 rpm showed uniform distribution of fine grains throughout the surface without any dark pits, pinholes and cracks.

  3. Electronic structure and spin coupling of the manganese dimer: The state of the art of ab initio approach.

    Science.gov (United States)

    Buchachenko, Alexei A; Chałasiński, Grzegorz; Szcześniak, Małgorzata M

    2010-01-14

    A thorough ab initio study of the Mn(2) dimer in its lowest electronic states that correlate to the ground Mn((6)S)+Mn((6)S) dissociation limit is reported. Performance of multireference methods is examined in calculations of the fully spin-polarized S=5((11) summation operator(+) (u)) state against the recent accurate single-reference coupled cluster CCSD(T) results [A. A. Buchachenko, Chem. Phys. Lett. 459, 73 (2008)]. The detailed comparison reveals a serious disagreement between the multireference configuration interaction (MRCI) and related nonperturbative results on the one hand and the complete active space perturbation theory (CASPT) calculations on the other. A striking difference found in the CASPT results of the second and third orders indicates poor perturbation expansion convergence. It is shown that a similar problem has affected most of the previous calculations performed using CASPT2 and similar perturbative approximations. The composition of the active space in the reference multiconfigurational self-consistent field calculations, the core correlation contribution, and basis set saturation effects are also analyzed. The lower spin states, S=0-4, are investigated using the MRCI method. The results indicate a similar dispersion binding for all the spin states within the manifold related to the closed 4s shells, which appears to screen and suppress the spin coupling between the half-filled 3d atomic shells. On this premise, the full set of model potentials is built by combining the accurate reference CCSD(T) interaction potential for S=5 and the MRCI spin-exchange energies for the SHeisenberg model. The effective spin-coupling parameter J is estimated as -3.9 cm(-1), a value roughly 2.5 times smaller in magnitude than those measured in the inert gas cryogenic matrices. Compressing of the Mn(2) dimer in the matrix cage is suggested as the prime cause of this disagreement.

  4. Visual study of domain structure in the spin reorientation range for (BiTm)3(FeGa)5O15 epitaxial films

    International Nuclear Information System (INIS)

    Belyaeva, A.I.; Antonov, A.V.; Egiazaryan, G.S.; Yur'ev, V.P.

    1980-01-01

    Carried out is visual study of the domain structure of (BiTm) 3 (FeGa) 5 O 12 ferrite-garnet epitaxial film with induced one-axial anisotropy within a wide temperature range of 4.2-400 K. Found is hysteresicless spin-reorientation phase transition, related to anisotropy change (light axis type on the anisotropy of light plane tyre). Intermediade state, connected with this transition, is investigated. It is shown, that double structure within temperature range Tsub(room)>=T>=Tsub(ph.tr) can be considered as thermodynamically equilibrium one

  5. Study of crystalline morphology and phase structure in poly(styrene-b-ethylene oxide-b-styrene) triblock copolymers bu solid state RMN spin diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Mantovani, Gerson L., E-mail: gerson.mantovani@ufabc.edu.b [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Engenharia, Modelagem e Ciencias Sociais Aplicadas; Bonk, Fabio A. [Universidade Estadual de Campinas (IQ/UNICAMP) SP (Brazil). Inst. de Quimica; Caldarelli, Stefano Caldarelli [Aix-Marseille Universite ISm2, Site de Saint Jerome, Marseille (France); Phan, Trang; Bertin, Denis [Universite de Provence, Site de Saint Jerome, Marseille (France); Azevedo, Eduardo R. de; Bonagamba, Tito J. [Universidade de Sao Paulo (IF/USP), Sao Carlos, SP (Brazil). Inst. de Fisica

    2009-07-01

    The phase structure and crystalline morphology of a series of polystyrene-b-polyethylene oxide-b-polystyrene (PS-b- PEO-b-PS) triblock copolymers, with different compositions and molecular weights, has been studied by solid-state NMR. WAXS and DSC measurements were used to detect the presence of crystalline domains of polyethylene oxide (PEO) blocks at room temperature as a function of the copolymer composition. {sup 1}H NMR spin diffusion analyses provided an estimation of the size of the dispersed phases of the nano structured copolymers. (author)

  6. Study of crystalline morphology and phase structure in poly(styrene-b-ethylene oxide-b-styrene) triblock copolymers bu solid state RMN spin diffusion

    International Nuclear Information System (INIS)

    Mantovani, Gerson L.; Phan, Trang; Bertin, Denis; Azevedo, Eduardo R. de; Bonagamba, Tito J.

    2009-01-01

    The phase structure and crystalline morphology of a series of polystyrene-b-polyethylene oxide-b-polystyrene (PS-b- PEO-b-PS) triblock copolymers, with different compositions and molecular weights, has been studied by solid-state NMR. WAXS and DSC measurements were used to detect the presence of crystalline domains of polyethylene oxide (PEO) blocks at room temperature as a function of the copolymer composition. 1 H NMR spin diffusion analyses provided an estimation of the size of the dispersed phases of the nano structured copolymers. (author)

  7. Measurement of the 3He Spin Structure Functions in the Resonance Region: A Test of Quark-Hadron Duality on the Neutron

    Energy Technology Data Exchange (ETDEWEB)

    Solvignon, Patricia [Temple Univ., Philadelphia, PA (United States)

    2006-08-01

    One of the biggest challenges in the study of the nucleon structure is the understanding of the transition from partonic degrees of freedom to hadronic degrees of freedom. In 1970, Bloom and Gilman noticed that structure function data taken at SLAC in the resonance region average to the scaling curve of deep inelastic scattering (DIS). Early theoretical interpretations suggested that these two very different regimes can be linked under the condition that the quark-gluon and quark-quark interactions are suppressed. Substantial efforts are ongoing to investigate this phenomenon both experimentally and theoretically. Quark-hadron duality has been confirmed for the unpolarized structure function F2 of the proton and the deuteron using data from the experimental Hall C at Jefferson Lab (JLab). Indications of duality have been seen for the proton polarized structure function g1 and the virtual photon asymmetry A1 at JLab Hall B and HERMES. Because of the different resonance behavior, it is expected that the onset of duality for the neutron will happen at lower momentum transfer than for the proton. Now that precise spin structure data in the DIS region are available at large x, data in the resonance region are greatly needed in order to test duality in spin-dependent structure functions. The goal of experiment E01-012 was to provide such data on the neutron (3He) in the moderate momentum transfer (Q2) region, 1.0 < Q2 < 4.0 (GeV/c2), where duality is expected to hold. The experiment ran successfully in early 2003 at Jefferson Lab in Hall B. It was an inclusive measurement of longitudinally polarized electrons scattering from a longitudinally or transversely polarized 3He target. Asymmetries and cross section differences were measured in order to extract the 3He spin structure function g1 and virtual photon asymmetry A1 in the resonance region. A test

  8. Spin asymmetries $A_1$ and structure functions $g_1$ of the proton and the deuteron from polarized high energy muon scattering

    CERN Document Server

    AUTHOR|(CDS)2067425; Arik, E; Arvidson, A; Badelek, B; Bardin, G; Baum, G; Berglund, P; Betev, L; Birsa, R; Björkholm, P; De Botton, N R; Boutemeur, M; Bradamante, Franco; Bravar, A; Bressan, A; Bültmann, S; Burtin, E; Cavata, C; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Derro, B R; Deshpande, A A; Dhawan, S K; Dulya, C M; Dyring, A; Eichblatt, S; Faivre, Jean-Claude; Fasching, D; Feinstein, F; Fernández, C; Forthmann, S; Frois, Bernard; Gallas, A; Garzón, J A; Gilly, H; Giorgi, M A; von Goeler, E; Görtz, S; Golutvin, I A; Gracia, G; De Groot, N; Grosse-Perdekamp, M; Haft, K; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; Kabuss, E M; Kageya, T; Karev, A G; Kessler, H J; Ketel, T; Kiryluk, J; Kiryushin, Yu T; Kishi, A; Kiselev, Yu F; Klostermann, L; Krämer, Dietrich; Krivokhizhin, V G; Kröger, W; Kukhtin, V V; Kurek, K; Kyynäräinen, J; Lamanna, M; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Lindqvist, T; Litmaath, M; Loewe, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Meyer, W T; Van Middelkoop, G; Miller, D; Miyachi, Y; Mori, K; Moromisato, J H; Nagaitsev, A P; Nassalski, J P; Naumann, Lutz; Niinikoski, T O; Oberski, J; Ogawa, A; Ozben, C; Pereira, H; Perrot-Kunne, F; Peshekhonov, V D; Piegia, R; Pinsky, L; Platchkov, S K; Pló, M; Pose, D; Postma, H; Pretz, J; Puntaferro, R; Pussieux, T; Rädel, G; Rijllart, A; Reicherz, G; Roberts, J; Rock, S E; Rodríguez, M; Rondio, Ewa; Ropelewski, Leszek; Sabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Schiller, A; Schüler, K P; Seitz, R; Semertzidis, Y K; Sergeev, S; Shanahan, P; Sichtermann, E P; Simeoni, F; Smirnov, G I; Staude, A; Steinmetz, A; Stiegler, U; Stuhrmann, H B; Szleper, M; Tessarotto, F; Thers, D; Tlaczala, W; Tripet, A; Ünel, G; Velasco, M; Vogt, J; Voss, Rüdiger; Whitten, C; Windmolders, R; Willumeit, R; Wislicki, W; Witzmann, A; Ylöstalo, J; Zanetti, A M; Zaremba, K; Zamiatin, N I; Zhao, J

    1998-01-01

    We present the final results of the spin asymmetries $A_1$ and the spin structure functions $g_1$ of the proton and the deuteron in the kinematic range $0.0008

  9. Measurement of the Q^{2} Dependence of the Deuteron Spin Structure Function g_{1} and its Moments at Low Q^{2} with CLAS.

    Science.gov (United States)

    Adhikari, K P; Deur, A; El Fassi, L; Kang, H; Kuhn, S E; Ripani, M; Slifer, K; Zheng, X; Adhikari, S; Akbar, Z; Amaryan, M J; Avakian, H; Ball, J; Balossino, I; Barion, L; Battaglieri, M; Bedlinskiy, I; Biselli, A S; Bosted, P; Briscoe, W J; Brock, J; Bültmann, S; Burkert, V D; Thanh Cao, F; Carlin, C; Carman, D S; Celentano, A; Charles, G; Chen, J-P; Chetry, T; Choi, S; Ciullo, G; Clark, L; Cole, P L; Contalbrigo, M; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; De Sanctis, E; Defurne, M; Djalali, C; Dodge, G E; Drozdov, V; Dupre, R; Egiyan, H; El Alaoui, A; Elouadrhiri, L; Eugenio, P; Fedotov, G; Filippi, A; Ghandilyan, Y; Gilfoyle, G P; Golovatch, E; Gothe, R W; Griffioen, K A; Guidal, M; Guler, N; Guo, L; Hafidi, K; Hakobyan, H; Hanretty, C; Harrison, N; Hattawy, M; Heddle, D; Hicks, K; Holtrop, M; Hyde, C E; Ilieva, Y; Ireland, D G; Isupov, E L; Jenkins, D; Jo, H S; Johnston, S C; Joo, K; Joosten, S; Kabir, M L; Keith, C D; Keller, D; Khachatryan, G; Khachatryan, M; Khandaker, M; Kim, W; Klein, A; Klein, F J; Konczykowski, P; Kovacs, K; Kubarovsky, V; Lanza, L; Lenisa, P; Livingston, K; Long, E; MacGregor, I J D; Markov, N; Mayer, M; McKinnon, B; Meekins, D G; Meyer, C A; Mineeva, T; Mirazita, M; Mokeev, V; Movsisyan, A; Munoz Camacho, C; Nadel-Turonski, P; Niculescu, G; Niccolai, S; Osipenko, M; Ostrovidov, A I; Paolone, M; Pappalardo, L; Paremuzyan, R; Park, K; Pasyuk, E; Payette, D; Phelps, W; Phillips, S K; Pierce, J; Pogorelko, O; Poudel, J; Price, J W; Prok, Y; Protopopescu, D; Raue, B A; Rizzo, A; Rosner, G; Rossi, P; Sabatié, F; Salgado, C; Schumacher, R A; Sharabian, Y G; Shigeyuki, T; Simonyan, A; Skorodumina, Iu; Smith, G D; Sparveris, N; Sokhan, D; Stepanyan, S; Strakovsky, I I; Strauch, S; Sulkosky, V; Taiuti, M; Tan, J A; Ungaro, M; Voutier, E; Wei, X; Weinstein, L B; Zhang, J; Zhao, Z W

    2018-02-09

    We measured the g_{1} spin structure function of the deuteron at low Q^{2}, where QCD can be approximated with chiral perturbation theory (χPT). The data cover the resonance region, up to an invariant mass of W≈1.9  GeV. The generalized Gerasimov-Drell-Hearn sum, the moment Γ_{1}^{d} and the spin polarizability γ_{0}^{d} are precisely determined down to a minimum Q^{2} of 0.02  GeV^{2} for the first time, about 2.5 times lower than that of previous data. We compare them to several χPT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the χPT domain.

  10. Measurement of the Q2 Dependence of the Deuteron Spin Structure Function g1 and its Moments at Low Q2 with CLAS

    Science.gov (United States)

    Adhikari, K. P.; Deur, A.; El Fassi, L.; Kang, H.; Kuhn, S. E.; Ripani, M.; Slifer, K.; Zheng, X.; Adhikari, S.; Akbar, Z.; Amaryan, M. J.; Avakian, H.; Ball, J.; Balossino, I.; Barion, L.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Bosted, P.; Briscoe, W. J.; Brock, J.; Bültmann, S.; Burkert, V. D.; Thanh Cao, F.; Carlin, C.; Carman, D. S.; Celentano, A.; Charles, G.; Chen, J.-P.; Chetry, T.; Choi, S.; Ciullo, G.; Clark, L.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Defurne, M.; Djalali, C.; Dodge, G. E.; Drozdov, V.; Dupre, R.; Egiyan, H.; El Alaoui, A.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Filippi, A.; Ghandilyan, Y.; Gilfoyle, G. P.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Isupov, E. L.; Jenkins, D.; Jo, H. S.; Johnston, S. C.; Joo, K.; Joosten, S.; Kabir, M. L.; Keith, C. D.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Konczykowski, P.; Kovacs, K.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; Long, E.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McKinnon, B.; Meekins, D. G.; Meyer, C. A.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Movsisyan, A.; Munoz Camacho, C.; Nadel-Turonski, P.; Niculescu, G.; Niccolai, S.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Pappalardo, L.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Payette, D.; Phelps, W.; Phillips, S. K.; Pierce, J.; Pogorelko, O.; Poudel, J.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Rizzo, A.; Rosner, G.; Rossi, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Shigeyuki, T.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sparveris, N.; Sokhan, D.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Sulkosky, V.; Taiuti, M.; Tan, J. A.; Ungaro, M.; Voutier, E.; Wei, X.; Weinstein, L. B.; Zhang, J.; Zhao, Z. W.; CLAS Collaboration

    2018-02-01

    We measured the g1 spin structure function of the deuteron at low Q2, where QCD can be approximated with chiral perturbation theory (χ PT ). The data cover the resonance region, up to an invariant mass of W ≈1.9 GeV . The generalized Gerasimov-Drell-Hearn sum, the moment Γ1d and the spin polarizability γ0d are precisely determined down to a minimum Q2 of 0.02 GeV2 for the first time, about 2.5 times lower than that of previous data. We compare them to several χ PT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the χ PT domain.

  11. Measuring a Country's Product Ladder and Technology Level based on Trade Flow

    Directory of Open Access Journals (Sweden)

    Jong-il Kim

    2006-06-01

    Full Text Available This study tries to quantify the technology level of products based on the concept of product ladder. While many studies on country technology competitiveness use the aggregate indices such as total factor productivity and revealed comparative advantage, this study estimates the ranking of about 2000 products in product ladder by using SITC 5 digit level export data. Based on the product ladder, this study measures the country and industry ranking and explores the characteristics of the ranking. It provides the international comparison of inter-industry and intra-industry ranking differences in product ladder. The statistical relationships between the ranking in product ladder and the determinants of technology level such as R&D and physical capital investment and wage, confirms that the measured ranking in product ladder could be regarded as an indirect indicator of technology level. The product ladder is applied to the estimation of production function to see the effect of the product differentiation on labor productivity.

  12. Spin-polarized relativistic linear-muffin-tin-orbital method: Volume-dependent electronic structure and magnetic moment of plutonium

    International Nuclear Information System (INIS)

    Solovyev, I.V.; Liechtenstein, A.I.; Gubanov, V.A.; Antropov, V.P.; Andersen, O.K.

    1991-01-01

    The linear-muffin-tin-orbital method is generalized to the case of relativistic and spin-polarized self-consistent band calculations. Our formalism is analogous to the standard orthogonal--linear-muffin-tin-orbital formalism, except that the potential functions and the potential parameters are now matrices. The method is used to perform density-functional calculations for fcc plutonium with different atomic volumes. The formation of spin and orbital magnetic moments, as well as the changes in the energy bands for volume changes corresponding to the α-δ transition, are investigated. The calculated magnetic moments agree quite well with the experimental ones

  13. Design of Dual Bandpass and Bandreject LC Ladder Filters

    Directory of Open Access Journals (Sweden)

    J. Hospodka

    2006-09-01

    Full Text Available This paper deals with the design of two-passband bandpass and two-stopband bandreject LC ladder filters. The design method is based on the special dual frequency transformation that transforms normalized lowpass to either bandpass with two passbands or to bandreject with two stopbands that are specified by four cutoff frequencies. The paper shows analytical solution relating these four cutoff frequencies to parameters of dual frequency transformation. It enables a direct computation of dual band LC filter elements from a normalized lowpass filter by means of simple relations. These relations have been implemented in the mathematical program Maple (TM as new user functions. They are supposed to be used as an enhancement of Syntfil package which is intended for analog filter design in program Maple. Specific application is shown on an example of the two-passband bandpass LC filter design.

  14. Entanglement entropy in random quantum spin-S chains

    International Nuclear Information System (INIS)

    Saguia, A.; Boechat, B.; Continentino, M. A.; Sarandy, M. S.

    2007-01-01

    We discuss the scaling of entanglement entropy in the random singlet phase (RSP) of disordered quantum magnetic chains of general spin S. Through an analysis of the general structure of the RSP, we show that the entanglement entropy scales logarithmically with the size of a block, and we provide a closed expression for this scaling. This result is applicable for arbitrary quantum spin chains in the RSP, being dependent only on the magnitude S of the spin. Remarkably, the logarithmic scaling holds for the disordered chain even if the pure chain with no disorder does not exhibit conformal invariance, as is the case for Heisenberg integer-spin chains. Our conclusions are supported by explicit evaluations of the entanglement entropy for random spin-1 and spin-3/2 chains using an asymptotically exact real-space renormalization group approach

  15. Quantum spin quadrumer

    Science.gov (United States)

    Khatua, Subhankar; Shankar, R.; Ganesh, R.

    2018-02-01

    A fundamental motif in frustrated magnetism is the fully mutually coupled cluster of N spins, with each spin coupled to every other spin. Clusters with N =2 and 3 have been extensively studied as building blocks of square and triangular lattice antiferromagnets. In both cases, large-S semiclassical descriptions have been fruitfully constructed, providing insights into the physics of macroscopic magnetic systems. Here, we develop a semiclassical theory for the N =4 cluster. This problem has rich mathematical structure with a ground-state space that has nontrivial topology. We show that ground states are appropriately parametrized by a unit vector order parameter and a rotation matrix. Remarkably, in the low-energy description, the physics of the cluster reduces to that of an emergent free spin-S spin and a rigid rotor. This successfully explains the spectrum of the quadrumer and its associated degeneracies. However, this mapping does not hold in the vicinity of collinear ground states due to a subtle effect that arises from the nonmanifold nature of the ground-state space. We demonstrate this by an analysis of soft fluctuations, showing that collinear states have a larger number of soft modes. Nevertheless, as these singularities only occur on a subset of measure zero, the mapping to a spin and a rotor provides a good description of the quadrumer. We interpret thermodynamic properties of the quadrumer that are accessible in molecular magnets, in terms of the rotor and spin degrees of freedom. Our study paves the way for field theoretic descriptions of systems such as pyrochlore magnets.

  16. TOPICAL REVIEW: Spin current, spin accumulation and spin Hall effect

    Directory of Open Access Journals (Sweden)

    Saburo Takahashi and Sadamichi Maekawa

    2008-01-01

    Full Text Available Nonlocal spin transport in nanostructured devices with ferromagnetic injector (F1 and detector (F2 electrodes connected to a normal conductor (N is studied. We reveal how the spin transport depends on interface resistance, electrode resistance, spin polarization and spin diffusion length, and obtain the conditions for efficient spin injection, spin accumulation and spin current in the device. It is demonstrated that the spin Hall effect is caused by spin–orbit scattering in nonmagnetic conductors and gives rise to the conversion between spin and charge currents in a nonlocal device. A method of evaluating spin–orbit coupling in nonmagnetic metals is proposed.

  17. Spin-photon entangling diode

    DEFF Research Database (Denmark)

    Flindt, Christian; Sørensen, A. S.; Lukin, M. D.

    2007-01-01

    We propose a semiconductor device that can electrically generate entangled electron spin-photon states, providing a building block for entanglement of distant spins. The device consists of a p-i-n diode structure that incorporates a coupled double quantum dot. We show that electronic control...... of the diode bias and local gating allow for the generation of single photons that are entangled with a robust quantum memory based on the electron spins. Practical performance of this approach to controlled spin-photon entanglement is analyzed....

  18. One-hundred-three compound band-structure benchmark of post-self-consistent spin-orbit coupling treatments in density functional theory

    Science.gov (United States)

    Huhn, William P.; Blum, Volker

    2017-08-01

    We quantify the accuracy of different non-self-consistent and self-consistent spin-orbit coupling (SOC) treatments in Kohn-Sham and hybrid density functional theory by providing a band-structure benchmark set for the valence and low-lying conduction energy bands of 103 inorganic compounds, covering chemical elements up to polonium. Reference energy band structures for the PBE density functional are obtained using the full-potential (linearized) augmented plane wave code wien2k, employing its self-consistent treatment of SOC including Dirac-type p1 /2 orbitals in the basis set. We use this benchmark set to benchmark a computationally simpler, non-self-consistent all-electron treatment of SOC based on scalar-relativistic orbitals and numeric atom-centered orbital basis functions. For elements up to Z ≈50 , both treatments agree virtually exactly. For the heaviest elements considered (Tl, Pb, Bi, Po), the band-structure changes due to SOC are captured with a relative deviation of 11% or less. For different density functionals (PBE versus the hybrid HSE06), we show that the effect of spin-orbit coupling is usually similar but can be dissimilar if the qualitative features of the predicted underlying scalar-relativistic band structures do not agree. All band structures considered in this work are available online via the NOMAD repository to aid in future benchmark studies and methods development.

  19. Spin gating electrical current

    Science.gov (United States)

    Ciccarelli, C.; Zârbo, L. P.; Irvine, A. C.; Campion, R. P.; Gallagher, B. L.; Wunderlich, J.; Jungwirth, T.; Ferguson, A. J.

    2012-09-01

    The level of the chemical potential is a fundamental parameter of the electronic structure of a physical system, which consequently plays an important role in defining the properties of active electrical devices. We directly measure the chemical potential shift in the relativistic band structure of the ferromagnetic semiconductor (Ga,Mn)As, controlled by changes in its magnetic order parameter. Our device comprises a non-magnetic aluminum single electron channel capacitively coupled to the (Ga,Mn)As gate electrode. The chemical potential shifts of the gate are directly read out from the shifts in the Coulomb blockade oscillations of the single electron transistor. The experiments introduce a concept of spin gating electrical current. In our spin transistor spin manipulation is completely removed from the electrical current carrying channel.

  20. Quantum spin transport in semiconductor nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, Christoph

    2012-05-15

    In this work, we study and quantitatively predict the quantum spin Hall effect, the spin-orbit interaction induced intrinsic spin-Hall effect, spin-orbit induced magnetizations, and spin-polarized electric currents in nanostructured two-dimensional electron or hole gases with and without the presence of magnetic fields. We propose concrete device geometries for the generation, detection, and manipulation of spin polarization and spin-polarized currents. To this end a novel multi-band quantum transport theory, that we termed the multi-scattering Buettiker probe model, is developed. The method treats quantum interference and coherence in open quantum devices on the same footing as incoherent scattering and incorporates inhomogeneous magnetic fields in a gauge-invariant and nonperturbative manner. The spin-orbit interaction parameters that control effects such as band energy spin splittings, g-factors, and spin relaxations are calculated microscopically in terms of an atomistic relativistic tight-binding model. We calculate the transverse electron focusing in external magnetic and electric fields. We have performed detailed studies of the intrinsic spin-Hall effect and its inverse effect in various material systems and geometries. We find a geometry dependent threshold value for the spin-orbit interaction for the inverse intrinsic spin-Hall effect that cannot be met by n-type GaAs structures. We propose geometries that spin polarize electric current in zero magnetic field and analyze the out-of-plane spin polarization by all electrical means. We predict unexpectedly large spin-orbit induced spin-polarization effects in zero magnetic fields that are caused by resonant enhancements of the spin-orbit interaction in specially band engineered and geometrically designed p-type nanostructures. We propose a concrete realization of a spin transistor in HgTe quantum wells, that employs the helical edge channel in the quantum spin Hall effect.