WorldWideScience

Sample records for chromatography-electron spin resonance

  1. 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.

  2. Multifrequency spin resonance in diamond

    CERN Document Server

    Childress, Lilian

    2010-01-01

    Magnetic resonance techniques provide a powerful tool for controlling spin systems, with applications ranging from quantum information processing to medical imaging. Nevertheless, the behavior of a spin system under strong excitation remains a rich dynamical problem. In this paper, we examine spin resonance of the nitrogen-vacancy center in diamond under conditions outside the regime where the usual rotating wave approximation applies, focusing on effects of multifrequency excitation and excitation with orientation parallel to the spin quantization axis. Strong-field phenomena such as multiphoton transitions and coherent destruction of tunneling are observed in the spectra and analyzed via numerical and analytic theory. In addition to illustrating the response of a spin system to strong multifrequency excitation, these observations may inform techniques for manipulating electron-nuclear spin quantum registers.

  3. Spin gravitational resonance and graviton detection

    CERN Document Server

    Quach, James Q

    2016-01-01

    We develop a gravitational analogue of spin magnetic resonance, called spin gravitational resonance, whereby a gravitational wave interacts with a magnetic field to produce a spin transition. In particular, an external magnetic field separates the energy spin states of a spin-1/2 particle, and the presence of the gravitational wave produces a perturbation in the components of the magnetic field orthogonal to the gravitational wave propagation. In this framework we test Dyson's conjecture that individual gravitons cannot be detected. Although we find no fundamental laws preventing single gravitons being detected with spin gravitational resonance, we show that it cannot be used in practice, in support of Dyson's conjecture.

  4. Simple classical approach to spin resonance phenomena

    DEFF Research Database (Denmark)

    Gordon, R A

    1977-01-01

    A simple classical method of describing spin resonance in terms of the average power absorbed by a spin system is discussed. The method has several advantages over more conventional treatments, and a number of important spin resonance phenomena, not normally considered at the introductory level...

  5. Observation of a hybrid spin resonance

    Science.gov (United States)

    Bai; Allgower; Ahrens; Alessi; Brown; Bunce; Cameron; Chu; Courant; Glenn; Huang; Jeon; Kponou; Krueger; Luccio; Makdisi; Lee; Ratner; Reece; Roser; Spinka; Syphers; Tsoupas; Underwood; van Asselt W; Williams

    2000-02-01

    A new type of spin depolarization resonance has been observed at the Brookhaven Alternating Gradient Synchrotron (AGS). This spin resonance is identified as a strong closed-orbit sideband around the dominant intrinsic spin resonance. The strength of the resonance was proportional to the 9th harmonic component of the horizontal closed orbit and proportional to the vertical betatron oscillation amplitude. This "hybrid" spin resonance cannot be overcome by the partial snake at the AGS, but it can be corrected by the harmonic orbit correctors. PMID:11017474

  6. Fermi liquid theory of resonant spin pumping

    OpenAIRE

    Moca, C. P.; Alex, A.; Shnirman, A.; Zarand, G.

    2013-01-01

    We study resonant all-electric adiabatic spin pumping through a quantum dot with two nearby levels by using a Fermi liquid approach in the strongly interacting regime, combined with a projective numerical renormalization group (NRG) theory. Due to spin-orbit coupling, a strong spin pumping resonance emerges at every charging transition, which allows for the transfer of a spin $~ \\hbar/2$ through the device in a single pumping cycle. Depending on the precise geometry of the device, controlled ...

  7. Towards Long Range Spin-Spin Interactions via Mechanical Resonators

    Science.gov (United States)

    Kabcenell, Aaron; Gieseler, Jan; Safira, Arthur; Kolkowitz, Shimon; Zibrov, Alexander; Harris, Jack; Lukin, Mikhail

    2016-05-01

    Nitrogen vacancy centers (NVs) are promising candidates for quantum computation, with room temperature optical spin read-out and initialization, microwave manipulability, and weak coupling to the environment resulting in long spin coherence times. The major outstanding challenge involves engineering coherent interactions between the spin states of spatially separated NV centers. To address this challenge, we are working towards the experimental realization of mechanical spin transducers. We have successfully fabricated magnetized high quality factor (Q> 105) , doubly-clamped silicon nitride mechanical resonators integrated close to a diamond surface, and report on experimental progress towards achieving the coherent coupling of the motion of these resonators with the electronic spin states of individual NV centers under cryogenic conditions. Such a system is expected to provide a scalable platform for mediating effective interactions between isolated spin qubits.

  8. Theoretical foundations of electron spin resonance

    CERN Document Server

    Harriman, John E

    2013-01-01

    Theoretical Foundations of Electron Spin Resonance deals with the theoretical approach to electron paramagnetic resonance. The book discusses electron spin resonance in applications related to polyatomic, probably organic, free radicals in condensed phases. The book also focuses on essentially static phenomena, that is, the description and determination of stationary-state energy levels. The author reviews the Dirac theory of the electron in which a four-component wave function is responsible for the behavior of the electron. The author then connects this theory with the nonrelativistic wave f

  9. Composite spin-1 resonances at the LHC

    CERN Document Server

    Low, Matthew; Wang, Lian-Tao

    2015-01-01

    In this paper, we discuss the signal of composite spin-1 resonances at the LHC. Motivated by the possible observation of a diboson resonance in the 8 TeV LHC data, we demonstrate that vector resonances from composite Higgs models are able to describe the data. We pay particular attention to the role played by fermion partial compositeness, which is a common feature in composite Higgs models. The parameter space that is both able to account for the diboson excess and passes electroweak precision and flavor tests is explored. Finally, we make projections for signals of such resonances at the 13 TeV run of the LHC.

  10. Spin-3/2 Pentaquark Resonance Signature

    International Nuclear Information System (INIS)

    We search for the standard lattice resonance signature of attraction between the resonance constituents which leads to a bound state at quark masses near the physical regime. We study a variety of spin-1/2 interpolators and for the first time, interpolators providing access to spin-3/2 pentaquark states. In looking for evidence of binding, a precise determination of the mass splitting between the pentaquark state and its lowest-lying decay channel is performed by constructing the effective mass splitting from the various two-point correlation functions. While the binding of the pentaquark state is not a requirement, the observation of such binding would provide compelling evidence for the existence of the theta+ pentaquark resonance. Evidence of binding is observed in the isoscalar spin-3/2 positive parity channel, making it an interesting state for further research

  11. Light quark spin symmetry in Zb resonances?

    Science.gov (United States)

    Voloshin, M. B.

    2016-04-01

    It is argued that the recent Belle data, consistent with no activity in the spectrum of the B*B ¯ +B B¯ * pairs at the mass of the Zb(10650 ) resonance, imply that the part of the interaction between heavy mesons that depends on the total spin of the light quark and antiquark is strongly suppressed. In particular, this part appears to be significantly weaker than can be inferred from pion exchange. If confirmed by future more detailed data, the symmetry with respect to the light quark spins, in combination with the heavy quark spin symmetry, would imply existence of four additional IG=1- resonances at the thresholds for heavy meson-antimeson pairs.

  12. Magnetic-resonance force microscopy measurement of entangled spin states

    International Nuclear Information System (INIS)

    We simulate magnetic-resonance force microscopy measurements of an entangled spin state. One of the entangled spins drives the resonant cantilever vibrations, while the other remote spin does not interact directly with the quasiclassical cantilever. The Schroedinger cat state of the cantilever (i.e., two trajectories of the quasiclassical cantilever) reveals two possible outcomes of the measurement for both entangled spins

  13. Magnetic Resonance Force Microscopy Measurement of Entangled Spin States

    CERN Document Server

    Berman, G P; Chapline, G; Hammel, P C; Tsifrinovich, V I

    2002-01-01

    We simulate magnetic resonance force microscopy measurements of an entangled spin state. One of the entangled spins drives the resonant cantilever vibrations, while the other remote spin does not interact directly with the quasiclassical cantilever. The Schr\\"odinger cat state of the cantilever reveals two possible outcomes of the measurement for both entangled spins.

  14. Electron spin resonance identification of irradiated fruits

    International Nuclear Information System (INIS)

    The electron spin resonance spectrum of achenes, pips, stalks and stones from irradiated fruits (stawberry, raspberry, red currant, bilberry, apple, pear, fig, french prune, kiwi, water-melon and cherry) always displays, just after γ-treatment, a weak triplet (aH ∼30 G) due to a cellulose radical; its left line (lower field) can be used as an identification test of irradiation, at least for strawberries, raspberries, red currants or bilberries irradiated in order to improve their storage time. (author)

  15. Electron-Spin Resonance in Boron Carbide

    Science.gov (United States)

    Wood, Charles; Venturini, Eugene L.; Azevedo, Larry J.; Emin, David

    1987-01-01

    Samples exhibit Curie-law behavior in temperature range of 2 to 100 K. Technical paper presents studies of electron-spin resonance of samples of hot pressed B9 C, B15 C2, B13 C2, and B4 C. Boron carbide ceramics are refractory solids with high melting temperatures, low thermal conductives, and extreme hardnesses. They show promise as semiconductors at high temperatures and have unusually large figures of merit for use in thermoelectric generators.

  16. Cavities for electron spin resonance: predicting the resonant frequency

    Science.gov (United States)

    Colton, John; Miller, Kyle; Meehan, Michael; Spencer, Ross

    Microwave cavities are used in electron spin resonance to enhance magnetic fields. Dielectric resonators (DRs), pieces of high dielectric material, can be used to tailor the resonant frequency of a cavity. However, designing cavities with DRs to obtain desired frequencies is challenging and in general can only be done numerically with expensive software packages. We present a new method for calculating the resonant frequencies and corresponding field modes for cylindrically symmetric cavities and apply it to a cavity with vertically stacked DRs. The modes of an arbitrary cavity are expressed as an expansion of empty cavity modes. The wave equation for D gives rise to an eigenvalue equation whose eigenvalues are the resonant frequencies and whose eigenvectors yield the electric and magnetic fields of the mode. A test against theory for an infinitely long dielectric cylinder inside an infinite cavity yields an accuracy better than 0.4% for nearly all modes. Calculated resonant frequencies are also compared against experiment for quasi-TE011 modes in resonant cavities with ten different configurations of DRs; experimental results agree with predicted values with an accuracy better than 1.0%. MATLAB code is provided at http://www.physics.byu.edu/research/coltonlab/cavityresonance.

  17. Spin resonance strength calculation through single particle tracking for RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Dutheil, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-03

    The strengths of spin resonances for the polarized-proton operation in the Relativistic Heavy Ion Collider are currently calculated with the code DEPOL, which numerically integrates through the ring based on an analytical approximate formula. In this article, we test a new way to calculate the spin resonance strengths by performing Fourier transformation to the actual transverse magnetic fields seen by a single particle traveling through the ring. Comparison of calculated spin resonance strengths is made between this method and DEPOL.

  18. Neutron Resonance Spin Determination Using Multi-Segmented Detector DANCE

    International Nuclear Information System (INIS)

    A sensitive method to determine the spin of neutron resonances is introduced based on the statistical pattern recognition technique. The new method was used to assign the spins of s-wave resonances in 155Gd. The experimental neutron capture data for these nuclei were measured with the DANCE (Detector for Advanced Neutron Capture Experiment) calorimeter at the Los Alamos Neutron Science Center. The highly segmented calorimeter provided detailed multiplicity distributions of the capture γ-rays. Using this information, the spins of the neutron capture resonances were determined. With these new spin assignments, level spacings are determined separately for s-wave resonances with Jπ = 1- and 2-.

  19. Overcoming Intrinsic Spin Resonances with an rf Dipole

    International Nuclear Information System (INIS)

    A coherent spin resonance excited by an rf dipole was used to overcome depolarization due to intrinsic spin resonances at the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory. We found that our data are consistent with a full spin flip of a polarized proton beam, without emittance growth, at Gγ=12+νz and 36-νz , by adiabatically exciting a vertical coherent betatron oscillation using a single rf dipole magnet. The interference pattern observed between the intrinsic spin resonance and the coherent spin resonance agrees well with multiparticle spin simulations based on a simple two-resonance model. The interference pattern can be used for beam diagnostics. copyright 1998 The American Physical Society

  20. Resonance fluorescence and electron spin in semiconductor quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yong

    2009-11-18

    The work presented in this dissertation contains the first observation of spin-resolved resonance fluorescence from a single quantum dot and its application of direct measurement of electron spin dynamics. The Mollow triplet and the Mollow quintuplet, which are the hallmarks of resonance fluorescence, are presented as the non-spin-resolved and spin-resolved resonance fluorescence spectrum, respectively. The negligible laser background contribution, the near pure radiative broadened spectrum and the anti-bunching photon statistics imply the sideband photons are background-free and near transform-limited single photons. This demonstration is a promising step towards the heralded single photon generation and electron spin readout. Instead of resolving spectrum, an alternative spin-readout scheme by counting resonance fluorescence photons under moderate laser power is demonstrated. The measurements of n-shot time-resolved resonance fluorescence readout are carried out to reveal electron spin dynamics of the measurement induced back action and the spin relaxation. Hyperfine interaction and heavy-light hole mixing are identified as the relevant mechanisms for the back action and phonon-assistant spin-orbit interaction dominates the spin relaxation. After a detailed discussion on charge-spin configurations in coupled quantum dots system, the single-shot readout on electron spin are proposed. (orig.)

  1. Current-induced spin torque resonance of a magnetic insulator

    Science.gov (United States)

    Schreier, Michael; Chiba, Takahiro; Niedermayr, Arthur; Lotze, Johannes; Huebl, Hans; Geprägs, Stephan; Takahashi, Saburo; Bauer, Gerrit E. W.; Gross, Rudolf; Goennenwein, Sebastian T. B.

    2015-10-01

    We report the observation of current-induced spin torque resonance in yttrium iron garnet/platinum bilayers. An alternating charge current at GHz frequencies in the platinum gives rise to dc spin pumping and spin Hall magnetoresistance rectification voltages, induced by the Oersted fields of the ac current and the spin Hall effect-mediated spin transfer torque. In ultrathin yttrium iron garnet films, we observe spin transfer torque actuated magnetization dynamics which are significantly larger than those generated by the ac Oersted field. Spin transfer torques thus efficiently couple charge currents and magnetization dynamics also in magnetic insulators, enabling charge current-based interfacing of magnetic insulators with microwave devices.

  2. Nuclear spin magnetic resonance force microscopy using slice modulation

    International Nuclear Information System (INIS)

    We report a Boltzmann polarization nuclear spins detection of cycle adiabatic inversion based on resonance slice thickness modulation. The nano-scale localized spin scanning NMRFM is applied using spins locked and anti-locked in the cycling frame. We also create a number of polarization spins among 1012 observing the spin relaxation and dipole-dipole interaction at gradient field 1520 T/m. The changes of nuclear spin signal intensity and relaxation time could be evidence for the nuclear collective excitation and predictions of nuclear spin collective excitation energy

  3. Spin-flip induction of Fano resonance upon electron tunneling through atomic-scale spin structures

    Energy Technology Data Exchange (ETDEWEB)

    Val' kov, V. V., E-mail: vvv@iph.krasn.ru; Aksenov, S. V., E-mail: asv86@iph.krasn.ru [Russian Academy of Sciences, Siberian Branch, Kirensky Institute of Physics (Russian Federation); Ulanov, E. A. [Siberian State Aerospace University (Russian Federation)

    2013-05-15

    The inclusion of inelastic spin-dependent electron scatterings by the potential profiles of a single magnetic impurity and a spin dimer is shown to induce resonance features due to the Fano effect in the transport characteristics of such atomic-scale spin structures. The spin-flip processes leading to a configuration interaction of the system's states play a fundamental role for the realization of Fano resonance and antiresonance. It has been established that applying an external magnetic field and a gate electric field allows the conductive properties of spin structures to be changed radically through the Fano resonance mechanism.

  4. Simple analytic formula for the strength of spin depolarizing resonance

    International Nuclear Information System (INIS)

    A simple analytic formula is derived to explain the periodicity of spin depolarizing resonance. The spin depolarizing resonance strengths of CPS and SPS at CERN and the lattices of meson factory at TRIUMF are used to compare with the analytic formula

  5. Spin tests of intermediate resonances in doubly radiative quarkonium decays

    International Nuclear Information System (INIS)

    Expressions for angular distributions of final particles in doubly radiative decays of quarkonium states are obtained from the helicity formalism. Cases considered are decay products of interfering resonances of closely spaced masses and resonances produced by transversely polarized leptons. In completion of an earlier work, the distribution for decay products of an intermediate resonance χ of spin 3 is also quoted to prove that the spin sχ of χ can be unambiguously determined for sχ≥3

  6. Spin injection and detection by resonant tunneling structure

    OpenAIRE

    Glazov, M.M.; Tarasenko, S. A.; Alekseev, P. S.; Odnoblyudov, M. A.; Chistyakov, V. M.; Yassievich, I. N.

    2004-01-01

    A theory of spin-dependent electron transmission through resonant tunneling diode (RTD) grown of non-centrosymmetrical semiconductor compounds has been presented. It has been shown that RTD can be employed for injection and detection of spin-polarized carriers: (i) electric current flow in the interface plane leads to spin polarization of the transmitted carriers, (ii) transmission of the spin-polarized carriers through the RTD is accompanied by generation of an in-plane electric current. The...

  7. Induction-detection electron spin resonance with spin sensitivity of a few tens of spins

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) is a spectroscopic method that addresses electrons in paramagnetic materials directly through their spin properties. ESR has many applications, ranging from semiconductor characterization to structural biology and even quantum computing. Although it is very powerful and informative, ESR traditionally suffers from low sensitivity, requiring many millions of spins to get a measureable signal with commercial systems using the Faraday induction-detection principle. In view of this disadvantage, significant efforts were made recently to develop alternative detection schemes based, for example, on force, optical, or electrical detection of spins, all of which can reach single electron spin sensitivity. This sensitivity, however, comes at the price of limited applicability and usefulness with regard to real scientific and technological issues facing modern ESR which are currently dealt with conventional induction-detection ESR on a daily basis. Here, we present the most sensitive experimental induction-detection ESR setup and results ever recorded that can detect the signal from just a few tens of spins. They were achieved thanks to the development of an ultra-miniature micrometer-sized microwave resonator that was operated at ∼34 GHz at cryogenic temperatures in conjunction with a unique cryogenically cooled low noise amplifier. The test sample used was isotopically enriched phosphorus-doped silicon, which is of significant relevance to spin-based quantum computing. The sensitivity was experimentally verified with the aid of a unique high-resolution ESR imaging approach. These results represent a paradigm shift with respect to the capabilities and possible applications of induction-detection-based ESR spectroscopy and imaging

  8. Induction-detection electron spin resonance with spin sensitivity of a few tens of spins

    Energy Technology Data Exchange (ETDEWEB)

    Artzi, Yaron; Twig, Ygal; Blank, Aharon [Schulich Faculty of Chemistry Technion—Israel Institute of Technology, Haifa 32000 (Israel)

    2015-02-23

    Electron spin resonance (ESR) is a spectroscopic method that addresses electrons in paramagnetic materials directly through their spin properties. ESR has many applications, ranging from semiconductor characterization to structural biology and even quantum computing. Although it is very powerful and informative, ESR traditionally suffers from low sensitivity, requiring many millions of spins to get a measureable signal with commercial systems using the Faraday induction-detection principle. In view of this disadvantage, significant efforts were made recently to develop alternative detection schemes based, for example, on force, optical, or electrical detection of spins, all of which can reach single electron spin sensitivity. This sensitivity, however, comes at the price of limited applicability and usefulness with regard to real scientific and technological issues facing modern ESR which are currently dealt with conventional induction-detection ESR on a daily basis. Here, we present the most sensitive experimental induction-detection ESR setup and results ever recorded that can detect the signal from just a few tens of spins. They were achieved thanks to the development of an ultra-miniature micrometer-sized microwave resonator that was operated at ∼34 GHz at cryogenic temperatures in conjunction with a unique cryogenically cooled low noise amplifier. The test sample used was isotopically enriched phosphorus-doped silicon, which is of significant relevance to spin-based quantum computing. The sensitivity was experimentally verified with the aid of a unique high-resolution ESR imaging approach. These results represent a paradigm shift with respect to the capabilities and possible applications of induction-detection-based ESR spectroscopy and imaging.

  9. PREFACE: Muon spin rotation, relaxation or resonance

    Science.gov (United States)

    Heffner, Robert H.; Nagamine, Kanetada

    2004-10-01

    To a particle physicist a muon is a member of the lepton family, a heavy electron possessing a mass of about 1/9 that of a proton and a spin of 1/2, which interacts with surrounding atoms and molecules electromagnetically. Since its discovery in 1937, the muon has been put to many uses, from tests of special relativity to deep inelastic scattering, from studies of nuclei to tests of weak interactions and quantum electrodynamics, and most recently, as a radiographic tool to see inside heavy objects and volcanoes. In 1957 Richard Garwin and collaborators, while conducting experiments at the Columbia University cyclotron to search for parity violation, discovered that spin-polarized muons injected into materials might be useful to probe internal magnetic fields. This eventually gave birth to the modern field of muSR, which stands for muon spin rotation, relaxation or resonance, and is the subject of this special issue of Journal of Physics: Condensed Matter. Muons are produced in accelerators when high energy protons (generally >500 MeV) strike a target like graphite, producing pions which subsequently decay into muons. Most experiments carried out today use relatively low-energy (~4 MeV), positively-charged muons coming from pions decaying at rest in the skin of the production target. These muons have 100% spin polarization, a range in typical materials of about 180 mg cm-2, and are ideal for experiments in condensed matter physics and chemistry. Negatively-charged muons are also occasionally used to study such things as muonic atoms and muon-catalysed fusion. The muSR technique provides a local probe of internal magnetic fields and is highly complementary to inelastic neutron scattering and nuclear magnetic resonance, for example. There are four primary muSR facilities in the world today: ISIS (Didcot, UK), KEK (Tsukuba, Japan), PSI (Villigen, Switzerland) and TRIUMF (Vancouver, Canada), serving about 500 researchers world-wide. A new facility, JPARC (Tokai, Japan

  10. Numerical simulation study on spin resonant depolarization due to spin-orbit coupling

    Institute of Scientific and Technical Information of China (English)

    Lan Jie-Qin; Xu Hong-Liang

    2012-01-01

    The spin polarization phenomenon in lepton circular accelerators had been known for many years.It provides a new approach for physicists to study the spin feature of fundamental particles and the dynamics of spin-orbit coupling,such as spin resonances.We use numerical simulation to study the features of spin under the modulation of orbital motion in an electron storage ring.The various cases of depolarization due to spin-orbit coupling through an emitting photon and misalignment of magnets in the ring are discussed.

  11. Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator

    Science.gov (United States)

    Polzikova, N. I.; Alekseev, S. G.; Pyataikin, I. I.; Kotelyanskii, I. M.; Luzanov, V. A.; Orlov, A. P.

    2016-05-01

    We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW) resonator (HBAR) formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE) this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determined by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.

  12. Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator

    Directory of Open Access Journals (Sweden)

    N. I. Polzikova

    2016-05-01

    Full Text Available We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW resonator (HBAR formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determined by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.

  13. Electron spin resonance investigations on polycarbonate irradiated with U ions

    International Nuclear Information System (INIS)

    Electron spin resonance investigations on polycarbonate irradiated with uranium ions are reported. The dependence of the resonance line parameters (line intensity, line width, double integral) on penetration depth and dose is studied. The nature of free radicals induced in polycarbonate by the incident ions is discussed in relation with the track structure. The presence of severe exchange interactions among free radicals is noticed

  14. The temperature dependence of quantum spin pumping generated using electron spin resonance with three-magnon splittings

    OpenAIRE

    NAKATA, KOUKI

    2013-01-01

    On the basis of the Schwinger–Keldysh formalism, we have closely investigated the temperature dependence of quantum spin pumping generated using electron spin resonance. We have clarified that three-magnon splittings excite non-zero modes of magnons and characterize the temperature dependence of quantum spin pumping generated using electron spin resonance.

  15. Micromagnetic understanding of stochastic resonance driven by spin-transfertorque

    CERN Document Server

    Finocchio, G; Cheng, X; Torres, L; Azzerboni, B

    2011-01-01

    In this paper, we employ micromagnetic simulations to study non-adiabatic stochastic resonance (NASR) excited by spin-transfer torque in a super-paramagnetic free layer nanomagnet of a nanoscale spin valve. We find that NASR dynamics involves thermally activated transitions among two static states and a single dynamic state of the nanomagnet and can be well understood in the framework of Markov chain rate theory. Our simulations show that a direct voltage generated by the spin valve at the NASR frequency is at least one order of magnitude greater than the dc voltage generated off the NASR frequency. Our computations also reproduce the main experimentally observed features of NASR such as the resonance frequency, the temperature dependence and the current bias dependence of the resonance amplitude. We propose a simple design of a microwave signal detector based on NASR driven by spin transfer torque.

  16. Telling the spin of the di-photon resonance

    CERN Document Server

    Fabbrichesi, Marco; Urbano, Alfredo

    2016-01-01

    We argue that the spin of the 750 GeV resonance can be determined at the 99.7% confidence level in the di-photon channel with as few as 10 fb$^{-1}$ of luminosity. This result is true if the resonance is produced by gluon fusion (independently of the selection cuts) while an appropriate choice of selection cuts is needed if quark production is sub-dominantly present--which is the case of the Kaluza-Klein gravitational excitation under the hypothesis of a spin-2 resonance. A proportionally larger luminosity is required if the model for the spin-2 resonance includes a dominant production by quarks or in the absence of an efficient separation of the signal from the background.

  17. Controllable strong coupling between individual spin qubits and a transmission line resonator via nanomechanical resonators

    International Nuclear Information System (INIS)

    We investigate a hybrid quantum system where an individual electronic spin qubit (EQ) and a transmission line resonator (TLR) are connected by a nanomechanical resonator (NAMR). We analyze the possibility of realizing a strong coupling between the EQ and the TLR. Compared with a direct coupling between an EQ and a TLR, the achieved coupling can be stronger and controllable. The proposal might be used to implement a high-fidelity quantum state transfer between the spin qubit and the TLR, and is scalable to involve several individual EQ-NAMR coupled systems with a TLR. -- Highlights: ► Strong coupling of a spin qubit to a transmission line resonator is achieved. ► The coupling is mediated by a nanomechanical resonator. ► The coupling is controllable and stronger than the direct spin-resonator coupling.

  18. Double-spin-flip resonance of rhodium nuclei at positive and negative spin temperatures

    DEFF Research Database (Denmark)

    Tuoriniemi, J.T.; Knuuttila, T.A.; Lefmann, K.;

    2000-01-01

    Sensitive SQUID-NMR measurements were used to study the mutual interactions in the highly polarized nuclear-spin system of rhodium metal. The dipolar coupling gives rise to a weak double-spin-flip resonance. The observed frequency shifts allow deducing separately the dipolarlike contribution...

  19. Double-spin-flip resonance of rhodium nuclei at positive and negative spin temperatures

    DEFF Research Database (Denmark)

    Tuoriniemi, J.T.; Knuuttila, T.A.; Lefmann, K.; Nummila, K.K.; Yao, W.; Rasmussen, F.B.

    2000-01-01

    Sensitive SQUID-NMR measurements were used to study the mutual interactions in the highly polarized nuclear-spin system of rhodium metal. The dipolar coupling gives rise to a weak double-spin-flip resonance. The observed frequency shifts allow deducing separately the dipolarlike contribution and...

  20. Study of spin resonances in the accelerators with snakes

    International Nuclear Information System (INIS)

    Spin resonances in the circular accelerators with snakes are studied to understand the nature of snake resonances. We analyze the effect of snake configuration, and the snake superperiod on the resonance. Defining the critical resonance strength ε/sub c/ as the maximum tolerable resonance strength without losing the beam polarization after passing through the resonance, we found that ε/sub c/ is a sensitive function of the snake configuration, the snake superperiod at the first order snake resonance, the higher order snake resonance conditions and the spin matching condition. Under properly designed snake configuration, the critical resonance strength ε/sub c/ is found to vary linearly with N/sub S/ as = (1/π)sin/sup /minus/1/(cos πν/sub z//sup /1/2//)N/sub S/, where ν/sub z/ and N/sub S/ are the betatron tune and the number of snakes respectively. We also study the effect of overlapping intrinsic and imperfection resonances. The imperfection resonance should be corrected to a magnitude of insignificance (e.g., ε≤0.1 for two snakes case) to maintain proper polarization. 23 refs., 25 figs

  1. Spin injection in a ferromagnet/resonant tunneling diode heterostructure

    Institute of Scientific and Technical Information of China (English)

    Jin Bao; Fang Wan; Yu Wang; Xiaoguang Xu; Yong Jiang

    2008-01-01

    The spin transport property of a ferromagnet (FM)/insulator (I)/resonant tunneling diode (RTD) heterostructure was stud-ied. The transmission coefficient and spin polarization in a multilayered heterostructure was calculated by a Scbr(o)dinger wave equa-tion. An Airy function formalism approach was used to solve this equation. Based on the transfer matrix approach, the transmittivity of the structure was determined as a function of the Feimi energy and other parameters. The result shows that the spin polarization induced by the structure oscillates with the increasing Fermi energy of the FM layer. While the thickness of the RTD is reduced, the resonant peaks become broad. In the heterostructure, the spin polarization reaches as high as 40% and can be easily controlled by the external bias voltage.

  2. Electron spin resonance study of NiO antiferromagnetic nanoparticles

    International Nuclear Information System (INIS)

    The electron spin resonance (ESR) spectra of antiferromagnetic nanoparticle NiO specimens have been investigated as a function of temperature at x-band (microwave) frequencies. Below the nominal Neel temperature, the x-band resonances arising from the bulk antiferromagnets, including NiO particles with diameters greater than 100 A, all vanish due to the emergence of large molecular exchange fields. The ESR resonance signals of 60 A antiferromagnetic nanoparticles, however, persist to the lowest temperatures. These nanoparticle resonance lines shift to lower fields rapidly as the temperature is decreased, while the lineshapes broaden and distort

  3. Matrix Formalism for Spin Dynamics Near a Single Depolarization Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alexander W.; /SLAC

    2005-10-26

    A matrix formalism is developed to describe the spin dynamics in a synchrotron near a single depolarization resonance as the particle energy (and therefore its spin precession frequency) is varied in a prescribed pattern as a function of time such as during acceleration. This formalism is first applied to the case of crossing the resonance with a constant crossing speed and a finite total step size, and then applied also to other more involved cases when the single resonance is crossed repeatedly in a prescribed manner consisting of linear ramping segments or sudden jumps. How repeated crossings produce an interference behavior is discussed using the results obtained. For a polarized beam with finite energy spread, a spin echo experiment is suggested to explore this interference effect.

  4. Reaching the quantum limit of sensitivity in electron spin resonance

    Science.gov (United States)

    Bienfait, A.; Pla, J. J.; Kubo, Y.; Stern, M.; Zhou, X.; Lo, C. C.; Weis, C. D.; Schenkel, T.; Thewalt, M. L. W.; Vion, D.; Esteve, D.; Julsgaard, B.; Mølmer, K.; Morton, J. J. L.; Bertet, P.

    2016-03-01

    The detection and characterization of paramagnetic species by electron spin resonance (ESR) spectroscopy is widely used throughout chemistry, biology and materials science, from in vivo imaging to distance measurements in spin-labelled proteins. ESR relies on the inductive detection of microwave signals emitted by the spins into a coupled microwave resonator during their Larmor precession. However, such signals can be very small, prohibiting the application of ESR at the nanoscale (for example, at the single-cell level or on individual nanoparticles). Here, using a Josephson parametric microwave amplifier combined with high-quality-factor superconducting microresonators cooled at millikelvin temperatures, we improve the state-of-the-art sensitivity of inductive ESR detection by nearly four orders of magnitude. We demonstrate the detection of 1,700 bismuth donor spins in silicon within a single Hahn echo with unit signal-to-noise ratio, reduced to 150 spins by averaging a single Carr-Purcell-Meiboom-Gill sequence. This unprecedented sensitivity reaches the limit set by quantum fluctuations of the electromagnetic field instead of thermal or technical noise, which constitutes a novel regime for magnetic resonance. The detection volume of our resonator is ˜0.02 nl, and our approach can be readily scaled down further to improve sensitivity, providing a new versatile toolbox for ESR at the nanoscale.

  5. Strong coupling of paramagnetic spins to a superconducting microwave resonator

    Energy Technology Data Exchange (ETDEWEB)

    Greifenstein, Moritz; Zollitsch, Christoph; Lotze, Johannes; Hocke, Fredrik; Goennenwein, Sebastian T.B.; Huebl, Hans [Walther-Meissner-Institut (WMI), Garching (Germany); Gross, Rudolf [Walther-Meissner-Institut (WMI), Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany)

    2012-07-01

    Under application of an external magnetic field, non-interacting electron spins behave as an ensemble of identical two-level-systems with tuneable transition frequency. When such an ensemble collectively interacts with a single mode of an electromagnetic resonator, the entire system can be described as two coupled quantum harmonic oscillators. The criterion for the observation of the so-called strong coupling regime is that the collective coupling strength g exceeds both the loss rate of the resonator {kappa} and of the spin ensemble {gamma}. In our experiment we realize a coupled spin-photon-system by introducing the spin marker DPPH (2,2-diphenyl-1-picrylhydrazyl) into the mode volume of a superconducting coplanar microwave resonator and investigate the interaction at 2.5, 5.0 and 7.5 GHz. For tuning the resonance, we apply an in-plane magnetic field and observe interaction at around {+-}90, {+-}180 and {+-}270 mT. While the coupling with the fundamental mode and the first harmonic mode of the resonator is identified as weak, the second harmonic shows g=21 MHz, {kappa} = 6 MHz and {gamma} = 5 MHz, i.e. the strong coupling regime. We further investigate the dependence of g on temperature and on microwave input power.

  6. Resonant tunneling diode with spin polarized injector

    OpenAIRE

    Slobodskyy, A.; Gould, C.; Slobodskyy, T.; Schmidt, G.; Molenkamp, L. W.; Sanchez, D

    2007-01-01

    We investigate the current-voltage characteristics of a II-VI semiconductor resonant-tunneling diode coupled to a diluted magnetic semiconductor injector. As a result of an external magnetic field, a giant Zeeman splitting develops in the injector, which modifies the band structure of the device, strongly affecting the transport properties. We find a large increase in peak amplitude accompanied by a shift of the resonance to higher voltages with increasing fields. We discuss a model which sho...

  7. Comments on ``Spin Connection Resonance in Gravitational General Relativity''

    CERN Document Server

    Bruhn, Gerhard W; Jadczyk, Arkadiusz

    2007-01-01

    We comment on a recent article of M.W.Evans, Acta Physica Polonica B38 (2007) 2211. We point out that the equations underlying Evans' theory are highly problematic. Moreover, we demonstrate that the so-called ``spin connection resonance'', predicted by Evans, cannot be derived from the equation he used. We provide an exact solution of Evans' corresponding equation and show that is has definitely no resonance solutions.

  8. Diphoton excess in phenomenological spin-2 resonance scenarios

    Science.gov (United States)

    Martini, Antony; Mawatari, Kentarou; Sengupta, Dipan

    2016-04-01

    We provide a possible explanation of a 750 GeV diphoton excess recently reported by both the ATLAS and CMS collaborations in the context of phenomenological spin-2 resonance scenarios, where the independent effective couplings of the resonance with gluons, quarks and photons are considered. We find a parameter region where the excess can be accounted for without conflicting with dijet constraints. We also show that the kinematical distributions might help to determine the couplings to gluons and quarks.

  9. Diphoton excess in phenomenological spin-2 resonance scenarios

    CERN Document Server

    Martini, Antony; Sengupta, Dipan

    2016-01-01

    We provide a possible explanation of a 750 GeV diphoton excess recently reported by both the ATLAS and CMS collaborations in the context of phenomenological spin-2 resonance scenarios, where the independent effective couplings of the resonance with gluons, quarks and photons are considered. We find a parameter region where the excess can be accounted for without conflicting with dijet constraints. We also show that the kinematical distributions might help to determine the couplings to gluons and quarks.

  10. Spin-resolved Fano resonances induced large spin Seebeck effects in graphene-carbon-chain junctions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yu-Shen; Zhang, Xue; Feng, Jin-Fu, E-mail: fengjinfu@cslg.edu.cn [Jiangsu Laboratory of Advanced Functional Materials and College of Physics and Engineering, Changshu Institute of Technology, Changshu 215500 (China); Wang, Xue-Feng, E-mail: xf-wang1969@yahoo.com [Department of Physics, Soochow University, Suzhou 215006 (China)

    2014-06-16

    We propose a high-efficiency thermospin device constructed by a carbon atomic chain sandwiched between two ferromagnetic (FM) zigzag graphene nanoribbon electrodes. In the low-temperature regime, the magnitude of the spin figure of merit is nearly equal to that of the corresponding charge figure of merit. This is attributed to the appearances of spin-resolved Fano resonances in the linear conductance spectrum resulting from the quantum interference effects between the localized states and the expanded states. The spin-dependent Seebeck effect is obviously enhanced near these Fano resonances with the same spin index; meanwhile, the Seebeck effect of the other spin component has a smaller value due to the smooth changing of the linear conductance with the spin index. Thus, a large spin Seebeck effect is achieved, and the magnitude of the spin figure of merit can reach 1.2 at T = 25 K. Our results indicate that the FM graphene-carbon-chain junctions can be used to design the high-efficiency thermospin devices.

  11. Spin-resolved Fano resonances induced large spin Seebeck effects in graphene-carbon-chain junctions

    International Nuclear Information System (INIS)

    We propose a high-efficiency thermospin device constructed by a carbon atomic chain sandwiched between two ferromagnetic (FM) zigzag graphene nanoribbon electrodes. In the low-temperature regime, the magnitude of the spin figure of merit is nearly equal to that of the corresponding charge figure of merit. This is attributed to the appearances of spin-resolved Fano resonances in the linear conductance spectrum resulting from the quantum interference effects between the localized states and the expanded states. The spin-dependent Seebeck effect is obviously enhanced near these Fano resonances with the same spin index; meanwhile, the Seebeck effect of the other spin component has a smaller value due to the smooth changing of the linear conductance with the spin index. Thus, a large spin Seebeck effect is achieved, and the magnitude of the spin figure of merit can reach 1.2 at T = 25 K. Our results indicate that the FM graphene-carbon-chain junctions can be used to design the high-efficiency thermospin devices.

  12. Electron spin resonance studies on reduction process of nitroxyl spin radicals used in molecular imaging

    International Nuclear Information System (INIS)

    The Electron spin resonance studies on the reduction process of nitroxyl spin probes were carried out for 1mM 14N labeled nitroxyl radicals in pure water and 1 mM concentration of ascorbic acid as a function of time. The electron spin resonance parameters such as signal intensity ratio, line width, g-value, hyperfine coupling constant and rotational correlation time were determined. The half life time was estimated for 1mM 14N labeled nitroxyl radicals in 1 mM concentration of ascorbic acid. The ESR study reveals that the TEMPONE has narrowest line width and fast tumbling motion compared with TEMPO and TEMPOL. From the results, TEMPONE has long half life time and high stability compared with TEMPO and TEMPOL radical. Therefore, this study reveals that the TEMPONE radical can act as a good redox sensitive spin probe for molecular imaging

  13. Spin isovector giant resonances in (n,p) reactions

    International Nuclear Information System (INIS)

    The present status of the study of spin-flip isovector giant resonances, using the (n,p) charge exchange reaction, is reviewed. After a brief history of the discovery of these giant resonances, a critical appraisal of the interpretation of the data in terms of giant resonances is given, along with some of the theoretical advances that impact on the interpretation of these data. A sampling of the results obtained for typical targets is given, followed by the interpretation of these results. A brief statement is made concerning the way forward in experimental technique for nuclear structure research using charge exchange reactions

  14. Spin-(3/2) pentaquark resonance signature in lattice QCD

    International Nuclear Information System (INIS)

    The possible discovery of the Θ+ pentaquark has motivated a number of studies of its nature using lattice QCD. While all the analyses thus far have focused on spin-(1/2) states, here we report the results of the first exploratory study in quenched lattice QCD of pentaquarks with spin (3/2). For the spin-(3/2) interpolating field we use a product of the standard N and K* operators. We do not find any evidence for the standard lattice resonance signature of attraction (i.e., binding at quark masses near the physical regime) in the JP=(3/2)- channel. Some evidence of binding is inferred in the isoscalar (3/2)+ channel at several quark masses, in accord with the standard lattice resonance signature. This suggests that this is a good candidate for the further study of pentaquarks on the lattice

  15. Spin-3/2 pentaquark resonance signature in lattice QCD

    International Nuclear Information System (INIS)

    The possible discovery of the Θ+ pentaquark has motivated a number of studies of its nature using lattice QCD. While all the analyses thus far have focussed on spin-1/2 states, here we report the results of the first exploratory study in quenched lattice QCD of pentaquarks with spin 3/2. For the spin-3/2 interpolating field we use a product of the standard N and K* operators. We do not find any evidence for the standard lattice resonance signature of attraction (i.e., binding at quark masses near the physical regime) in the JP=(3-)/(2) channel. Some evidence of binding is inferred in the isoscalar (3+)/(2) channel at several quark masses, in accord with the standard lattice resonance signature. This suggests that this is a good candidate for the further study of pentaquarks on the lattice. (orig.)

  16. Field integral correction in neutron resonance spin echo

    International Nuclear Information System (INIS)

    Neutron resonance spin echo (NRSE) as a variant of neutron spin echo (NSE) has the advantage that it needs only relatively small magnetic coils. Field inhomogeneities are therefore less important than in NSE. We have built a new type of NRSE spectrometer that overcomes the main limitation of NRSE towards high-energy resolution. Our setup profits from a new longitudinal NRSE field geometry which allows to use Fresnel coils correcting for the beam divergence effect, while former NRSE setups with transversal static magnetic fields could not use Fresnel coils. We demonstrate the function of the longitudinal resonance flip coils, and show first results of spin echo test measurements performed by means of the new setup

  17. Resonant Spin Wave Excitation by Terahertz Magnetic Near-field Enhanced with Split Ring Resonator

    CERN Document Server

    Mukai, Y; Yamamoto, T; Kageyama, H; Tanaka, K

    2014-01-01

    Excitation of antiferromagnetic spin waves in HoFeO$_{3}$ crystal combined with a split ring resonator (SRR) is studied using terahertz (THz) electromagnetic pulses. The magnetic field in the vicinity of the SRR induced by the incident THz electric field component excites and the Faraday rotation of the polarization of a near-infrared probe pulse directly measures oscillations that correspond to the antiferromagnetic spin resonance mode. The good agreement of the temperature-dependent magnetization dynamics with the calculation using the two-lattice Landau-Lifshitz-Gilbert equation confirms that the spin wave is resonantly excited by the THz magnetic near-field enhanced at the LC resonance frequency of the SRR, which is 20 times stronger than the incident magnetic field.

  18. Enhancement of Spin-transfer torque switching via resonant tunneling

    Energy Technology Data Exchange (ETDEWEB)

    Chatterji, Niladri [Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India); Tulapurkar, Ashwin A.; Muralidharan, Bhaskaran [Center of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India)

    2014-12-08

    We propose the use of resonant tunneling as a route to enhance the spin-transfer torque switching characteristics of magnetic tunnel junctions. The proposed device structure is a resonant tunneling magnetic tunnel junction based on a MgO-semiconductor heterostructure sandwiched between a fixed magnet and a free magnet. Using the non-equilibrium Green's function formalism coupled self consistently with the Landau-Lifshitz-Gilbert-Slonczewski equation, we demonstrate enhanced tunnel magneto-resistance characteristics as well as lower switching voltages in comparison with traditional trilayer devices. Two device designs based on MgO based heterostructures are presented, where the physics of resonant tunneling leads to an enhanced spin transfer torque thereby reducing the critical switching voltage by up to 44%. It is envisioned that the proof-of-concept presented here may lead to practical device designs via rigorous materials and interface studies.

  19. Gaussian approximation and single-spin measurement in magnetic resonance force microscopy with spin noise

    International Nuclear Information System (INIS)

    A promising technique for measuring single electron spins is magnetic resonance force microscopy (MRFM), in which a microcantilever with a permanent magnetic tip is resonantly driven by a single oscillating spin. The most effective experimental technique is the oscillating cantilever-driven adiabatic reversals (OSCAR) protocol, in which the signal takes the form of a frequency shift. If the quality factor of the cantilever is high enough, this signal will be amplified over time to the point where it can be detected by optical or other techniques. An important requirement, however, is that this measurement process occurs on a time scale that is short compared to any noise which disturbs the orientation of the measured spin. We describe a model of spin noise for the MRFM system and show how this noise is transformed to become time dependent in going to the usual rotating frame. We simplify the description of the cantilever-spin system by approximating the cantilever wave function as a Gaussian wave packet and show that the resulting approximation closely matches the full quantum behavior. We then examine the problem of detecting the signal for a cantilever with thermal noise and spin with spin noise, deriving a condition for this to be a useful measurement.

  20. Correlation between spin Hall angle and spin diffusion length determined by means of spin torque ferromagnetic resonance technique

    International Nuclear Information System (INIS)

    Spin torque ferromagnetic resonance (ST-FMR) in ferromagnetic metal (FM)/nonmagnetic metal (NM) bilayer films is one of the powerful methods to determine the spin Hall angle (SHA), conversion yield between charge and spin currents. Here we describe how to estimate the SHA and the spin diffusion length (SDL) from ST-FMR spectra. Although these two are fundamental parameters to characterize the spin Hall effect (SHE), there is still a heavy debate regarding their magnitudes even for platinum, which is the standard SHE material; reported values of SHA and SDL using FM/NM bilayer films vary very widely and there seems to be no correlation among SHA, SDL, and resistivity. In this work, we relate the three important physical quantities, i.e., SHA, SDL and resistivity, from their temperature dependences. (author)

  1. Randomized benchmarking of quantum gates implemented by electron spin resonance

    Science.gov (United States)

    Park, Daniel K.; Feng, Guanru; Rahimi, Robabeh; Baugh, Jonathan; Laflamme, Raymond

    2016-06-01

    Spin systems controlled and probed by magnetic resonance have been valuable for testing the ideas of quantum control and quantum error correction. This paper introduces an X-band pulsed electron spin resonance spectrometer designed for high-fidelity coherent control of electron spins, including a loop-gap resonator for sub-millimeter sized samples with a control bandwidth ∼40 MHz. Universal control is achieved by a single-sideband upconversion technique with an I-Q modulator and a 1.2 GS/s arbitrary waveform generator. A single qubit randomized benchmarking protocol quantifies the average errors of Clifford gates implemented by simple Gaussian pulses, using a sample of gamma-irradiated quartz. Improvements in unitary gate fidelity are achieved through phase transient correction and hardware optimization. A preparation pulse sequence that selects spin packets in a narrowed distribution of static fields confirms that inhomogeneous dephasing (1 / T2∗) is the dominant source of gate error. The best average fidelity over the Clifford gates obtained here is 99.2 % , which serves as a benchmark to compare with other technologies.

  2. Analysis and approximations for crossing two nearby spin resonances

    International Nuclear Information System (INIS)

    Solutions to the T-BMT spin equation have to date been confined to the single resonance crossing. However, in reality most cases of interest concern the overlapping of several resonances. To date there has been several serious studies of this problem; however, a good analytical solution or even approximation has eluded the community. We show that the T-BMT equation can be transformed into a Hill's like equation. In this representation it can be shown that, while the single resonance crossing represents the solution to the Parabolic Cylinder equation, the overlapping case becomes a parametric type of resonance. We present possible approximations for both the non-accelerating case and accelerating case.

  3. Hybrid Electron Spin Resonance and Whispering Gallery Mode Resonance Spectroscopy of Fe3+ in Sapphire

    OpenAIRE

    Benmessai, Karim; Farr, Warrick G.; Creedon, Daniel L.; Reshitnyk, Yarema; Floch, Jean-Michel Le; Duty, Timothy; Tobar, Michael E.

    2013-01-01

    The development of a new era of quantum devices requires an understanding of how paramagnetic dopants or impurity spins behave in crystal hosts. Here, we describe a new spectroscopic technique which uses traditional Electron Spin Resonance (ESR) combined with the measurement of a large population of electromagnetic Whispering Gallery (WG) modes. This allows the characterization of the physical parameters of paramagnetic impurity ions in the crystal at low temperatures. We present measurements...

  4. RESPECT: Neutron Resonance Spin-Echo Spectrometer for Extreme Studies

    CERN Document Server

    Georgii, Robert; Pfleiderer, Christian; Böni, Peter

    2016-01-01

    We propose the design of a Resonance SPin-echo spECtrometer for exTreme studies, RESPECT, that is ideally suited for the exploration of non-dispersive processes such as diffusion, crystallization, slow dynamics, tunneling processes, crystal electric field excitations, and spin fluctuations. It is a variant of the conventional neutron spin-echo technique (NSE) by i) replacing the long precession coils by pairs of longitudinal neutron spin-echo coils combined with RF-spin flippers and ii) by stabilizing the neutron polarization with small longitudinal guide fields that can in addition be used as field subtraction coils thus allowing to adjust the field integrals over a range of 8 orders of magnitude. Therefore, the dynamic range of RESPECT can in principle be varied over 8 orders of magnitude in time, if neutrons with the required energy are made available. Similarly as for existing NSE-spectrometers, spin echo times of up to approximately 1 microsecond can be reached if the divergence and the correction elemen...

  5. Spin injection in n-type resonant tunneling diodes

    Science.gov (United States)

    Orsi Gordo, Vanessa; Herval, Leonilson KS; Galeti, Helder VA; Gobato, Yara Galvão; Brasil, Maria JSP; Marques, Gilmar E.; Henini, Mohamed; Airey, Robert J.

    2012-10-01

    We have studied the polarized resolved photoluminescence of n-type GaAs/AlAs/GaAlAs resonant tunneling diodes under magnetic field parallel to the tunnel current. Under resonant tunneling conditions, we have observed two emission lines attributed to neutral (X) and negatively charged excitons (X-). We have observed a voltage-controlled circular polarization degree from the quantum well emission for both lines, with values up to -88% at 15 T at low voltages which are ascribed to an efficient spin injection from the 2D gases formed at the accumulation layers.

  6. Spin dependent electron transport through a magnetic resonant tunneling diode

    OpenAIRE

    Havu, Paula; Tuomisto, Noora; Vaananen, Riikka; Puska, Martti J.; Nieminen, Risto M.

    2004-01-01

    Electron transport properties in nanostructures can be modeled, for example, by using the semiclassical Wigner formalism or the quantum mechanical Green's functions formalism. We compare the performance and the results of these methods in the case of magnetic resonant-tunneling diodes. We have implemented the two methods within the self-consistent spin-density-functional theory. Our numerical implementation of the Wigner formalism is based on the finite-difference scheme whereas for the Green...

  7. A capacitive probe for Electron Spin Resonance detection

    Science.gov (United States)

    Aloisi, Giovanni; Dolci, David; Carlà, Marcello; Mannini, Matteo; Piuzzi, Barbara; Caneschi, Andrea

    2016-02-01

    The use of the magnetic field associated with Maxwell displacement current in a capacitor is proposed for the detection of Electron Spin Resonance. A probe based on this concept is realized and successfully tested with CW radio-frequency in the band going from 200 MHz to 1 GHz with a DPPH sample. A significant increase of Signal to Noise Ratio is observed while increasing the frequency.

  8. Nuclear Tuning and Detuning of the Electron Spin Resonance in a Quantum Dot

    OpenAIRE

    Danon, Jeroen; Nazarov, Yuli V.

    2007-01-01

    We study nuclear spin dynamics in a quantum dot close to the conditions of electron spin resonance. We show that at small frequency mismatch the nuclear field detunes the resonance. Remarkably, at larger frequency mismatch its effect is opposite: The nuclear system is bistable, and in one of the stable states the field accurately tunes the electron spin splitting to resonance. In this state the nuclear field fluctuations are strongly suppressed and nuclear spin relaxation is accelerated.

  9. Nuclear Tuning and Detuning of the Electron Spin Resonance in a Quantum Dot: Theoretical Consideration

    OpenAIRE

    Danon, J.; Nazarov, Y. V.

    2008-01-01

    We study nuclear spin dynamics in a quantum dot close to the conditions of electron spin resonance. We show that at a small frequency mismatch, the nuclear field detunes the resonance. Remarkably, at larger frequency mismatch, its effect is opposite: The nuclear system is bistable, and in one of the stable states, the field accurately tunes the electron spin splitting to resonance. In this state, the nuclear field fluctuations are strongly suppressed, and nuclear spin relaxation is accelerated.

  10. Electron-spin resonance and Rabi oscillations on helium nanodroplets

    International Nuclear Information System (INIS)

    Full text: Superfluid helium nanodroplets provide a versatile substrate for cooling atoms and molecules and, if desired, assemble weakly bound complexes. Electron-spin resonance (ESR) is a versatile probe of the electronic environment in radicals and, via spin tags, in ESR-silent species. We demonstrate the first application of ESR to doped helium nanodroplets and exploit the scheme of optically-detected magnetic resonance (ODMR). We measure sharp, hyperfine-resolved, ESR spectra of single K and Rb atoms isolated on He nanodroplets. The shift of the ESR lines with respect to free atoms directly reflects the distortion of the valence-electron wavefunction due to the He nanodroplet. We are able to follow this change as a function of droplet size. The observation of Rabi oscillations indicates a long decoherence time and demonstrates our ability to perform coherent manipulation of the spin. We are currently constructing a high-temperature pickup source, based on electron bombardment, to extend the method to transition metal atoms with high spin-multiplicity. (author)

  11. Photo-production of Nucleon Resonances and Nucleon Spin Structure Function in the Resonance Region

    CERN Document Server

    Qing, D; Qing, Di; Schmidt, Ivan

    2002-01-01

    The photo-production of nucleon resonances is calculated based on a chiral constituent quark model including both relativistic corrections H{rel} and two-body exchange currents, and it is shown that these effects play an important role. We also calculate the first moment of the nucleon spin structure function g1 (x,Q^2) in the resonance region, and obtain a sign-changing point around Q^2 ~ 0.27 {GeV}^2 for the proton.

  12. Force detected electron spin resonance at 94 GHz.

    Science.gov (United States)

    Cruickshank, Paul A S; Smith, Graham M

    2007-01-01

    Force detected electron spin resonance (FDESR) detects the presence of unpaired electrons in a sample by measuring the change in force on a mechanical resonator as the magnetization of the sample is modulated under magnetic resonance conditions. The magnetization is coupled to the resonator via a magnetic field gradient. It has been used to both detect and image distributions of electron spins, and it offers both extremely high absolute sensitivity and high spatial imaging resolution. However, compared to conventional induction mode ESR the technique also has a comparatively poor concentration sensitivity and it introduces complications in interpreting and combining both spectroscopy and imaging. One method to improve both sensitivity and spectral resolution is to operate in high magnetic fields in order to increase the sample magnetization and g-factor resolution. In this article we present FDESR measurements on the organic conductor (fluoranthene)(2)PF(6) at 3.2 T, with a corresponding millimeter-wave frequency of 93.5 GHz, which we believe are the highest field results for FDESR reported in the literature to date. A magnet-on-cantilever approach was used, with a high-anisotropy microwave ferrite as the gradient source and employing cyclic saturation to modulate the magnetization at the cantilever fundamental frequency. PMID:17503940

  13. Modeling the neutron spin-flip process in a time-of-flight spin-resonance energy filter

    CERN Document Server

    Parizzi, A A; Klose, F

    2002-01-01

    A computer program for modeling the neutron spin-flip process in a novel time-of-flight (TOF) spin-resonance energy filter has been developed. The software allows studying the applicability of the device in various areas of spallation neutron scattering instrumentation, for example as a dynamic TOF monochromator. The program uses a quantum-mechanical approach to calculate the local spin-dependent spectra and is essential for optimizing the magnetic field profiles along the resonator axis. (orig.)

  14. Sensitivity and spatial resolution for electron-spin-resonance detection by magnetic resonance force microscopy

    International Nuclear Information System (INIS)

    The signal intensity of electron spin resonance in magnetic resonance force microscopy (MRFM) experiments employing periodic saturation of the electron spin magnetization is determined by four parameters: the rf field H1, the modulation level of the bias field Hm, the spin relaxation time τ1, and the magnetic size R(∂H/∂z) of the sample. Calculations of the MRFM spectra obtained from a 2,2-diphenyl-1-picrylhydrazyl particle have been performed for various conditions. The results are compared with experimental data and excellent agreement is found. The systematic variation of the signal intensity as a function of H1 and Hm provides a powerful tool to characterize the MRFM apparatus. copyright 1996 American Institute of Physics

  15. Implementation of the perfect state transfer speeded up by three- spin interactions using nuclear magnetic resonance

    CERN Document Server

    Zhang, J; Suter, D; Peng, Xinhua; Suter, Dieter; Zhang, Jingfu

    2005-01-01

    The speed of perfect state transfer (PST) can be increased by the three- spin interactions in the spin XY chain. By decomposing the evolution of the spin XY chain with three- spin interactions into a series of single- spin rotations and the J- coupling evolutions between the neighboring spins, we simulate such a chain and implement the stepped-up PST using a nuclear magnetic resonance (NMR) quantum computer.

  16. Splitting of the Dipole and Spin-Dipole Resonances

    CERN Document Server

    Austin, S M; Galonsky, A; Nees, T; Sterrenburg, W A; Bainum, D E; Rapaport, J; Sugarbaker, E R; Foster, C C; Goodman, C D; Horen, D J; Goulding, C A; Greenfield, M B; Austin, Sam M.

    2001-01-01

    Cross sections for the 90,92,94Zr(p,n) reactions were measured at energies of 79.2 and 119.4 MeV. A phenomenological model was developed to describe the variation with bombarding energy of the position of the L=1 peak observed in these and other (p,n) reactions. The model yields the splitting between the giant dipole and giant spin dipole resonances. Values of these splittings are obtained for isotopes of Zr and Sn and for 208Pb.

  17. Random spin signal in magnetic resonance force microscopy

    International Nuclear Information System (INIS)

    We study a random magnetic resonance force microscopy (MRFM) signal caused by the thermal vibrations of high frequency cantilever modes in the oscillating cantilever-driven adiabatic reversals (OSCAR) technique. We show that the regular MRFM signal with a characteristic decay time, τm, is followed by a non-dissipative random signal with a characteristic time τr. We present the estimates for the values of τm and τr. We argue that this random MRFM signal can be used for spin detection. It has a 'signature' of a sharp peak in its Fourier spectrum

  18. Electron spin resonance of Er3+ in YBiPt

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) experiments at 4.15 K of Er3+ in YBiPt show that Er3+ is in a site of cubic local symmetry, with a Γ(3)8 ground state and an overall crystal field splitting of ∝85(10) K. We inferred from the spectra the existence of lattice distortions at the rare-earth (RE) site. These results may help in understanding the heavy-fermion system YbBiPt, which has the same structure as YBiPt. (orig.)

  19. Electron spin resonance as a method of dating

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) dating is closely related to thermoluminescence (TL) dating. The principle and procedures of ESR are described together with the application to archaeological materials excavated at Petralona cave in Greece. Atomic models of defects responsible for TL and ESR in calcite are discussed. The age is deduced from the archaeological dose, the total dose of the natural radiation determined by ESR signal intensities, and from the dose rate. The ages by ESR dating are compared with those by TL and 14C dating and also by U-Th dating. The applications to geological and anthropological materials are described with main emphasis on cave deposits. (author)

  20. Harmonic trap resonance enhanced synthetic atomic spin-orbit coupling

    Science.gov (United States)

    Wu, Ling-Na; Luo, Xinyu; Xu, Zhi-Fang; Ueda, Masahito; Wang, Ruquan; You, Li

    2016-05-01

    The widely adopted scheme for synthetic atomic spin-orbit coupling (SOC) is based on the momentum sensitive Raman coupling, which is easily implemented in one spatial dimension. Recently, schemes based on pulsed or periodically modulating gradient magnetic field (GMF) were proposed and the main characteristic features have subsequently been demonstrated. The present work reports an experimental discovery and the associated theoretical understanding of tuning the SOC strength synthesized with GMF through the motional resonance of atomic center-of-mass in a harmonic trap. In some limits, we observe up to 10 times stronger SOC compared to the momentum impulse from GMF for atoms in free space.

  1. Determination of the spin channel contributions to the yttrium p-resonances

    International Nuclear Information System (INIS)

    The angular dependence of neutron scattering by 89Y nuclei has been measured. In the energy range up to about 25 keV, areas for a number of strong resonances are determined. On the basis of the changes in the areas with the scattering angle, conclusions are drawn as to the spins of some p-resonances. For p-resonances with a unit spin, the values of the contributions from two different channnels with different spin values are obtained

  2. Disorder effect of resonant spin Hall effect in a tilted magnetic field

    OpenAIRE

    Shen, SQ; Zhang, FC; Jiang, ZF

    2009-01-01

    We study the disorder effect of resonant spin Hall effect in a two-dimensional electron system with Rashba coupling in the presence of a tilted magnetic field. The competition between the Rashba coupling and the Zeeman coupling leads to the energy crossing of the Landau levels, which gives rise to the resonant spin Hall effect. Utilizing the Streda's formula within the self-consistent Born approximation, we find that the impurity scattering broadens the energy levels and the resonant spin Hal...

  3. Resonant harmonic generation and collective spin rotations in electrically driven quantum dots

    OpenAIRE

    Nowak, M. P.; Szafran, B.; Peeters, F.M.

    2016-01-01

    Spin rotations induced by an AC electric field in a two-electron double quantum dot are studied by an exact numerical solution of the time dependent Schroedinger equation in the context of recent electric dipole spin resonance experiments based on the Pauli blockade. We demonstrate that the splitting of the main resonance line by the spin exchange coupling is accompanied by the appearance of fractional resonances and that both these effects are triggered by interdot tunnel coupling. We find t...

  4. Resonant spin-flavour precession of neutrinos and pulsar velocities

    International Nuclear Information System (INIS)

    Young pulsars are known to exhibit large space velocities, up to 103 km/s. We propose a new mechanism for the generation of these large velocities based on an asymmetric emission of neutrinos during the supernova explosion. The mechanism involves the resonant spin-flavour precession of neutrinos with a transition magnetic moment in the magnetic field of the supernova. The asymmetric emission of neutrinos is due the distortion of the resonance surface by matter polarization effects in the supernova magnetic field. The requisite values of the field strengths and neutrino parameters are estimated for various neutrino conversions caused by their Dirac or Majorana-type transition magnetic moments. (author). 30 refs, 1 tab

  5. Spin-selected resonant tunneling through a magnetic-controlled diode

    International Nuclear Information System (INIS)

    The spin resonant tunneling through a semiconductor double-barrier structure are investigated by solving static Schroedinger equations. In the case of symmetric double barriers, both spin-up and spin-down electrons show resonant tunneling, but the peaks appear at different magnetic field. This can be used to realize magnetic-controlled spin filter. We perform calculation of conductance and conclude that the conductance decreases by increasing the temperature. The results may shed light on the possibility of designing resonant-tunneling devices and spin selecting systems

  6. Spin-selected resonant tunneling through a magnetic-controlled diode

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yongmei [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Xiong Shijie [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China)]. E-mail: sjxiong@nju.edu.cn

    2005-05-15

    The spin resonant tunneling through a semiconductor double-barrier structure are investigated by solving static Schroedinger equations. In the case of symmetric double barriers, both spin-up and spin-down electrons show resonant tunneling, but the peaks appear at different magnetic field. This can be used to realize magnetic-controlled spin filter. We perform calculation of conductance and conclude that the conductance decreases by increasing the temperature. The results may shed light on the possibility of designing resonant-tunneling devices and spin selecting systems.

  7. Understanding and controlling spin-systems using electron spin resonance techniques

    Science.gov (United States)

    Martens, Mathew

    Single molecule magnets (SMMs) posses multi-level energy structures with properties that make them attractive candidates for implementation into quantum information technologies. However there are some major hurdles that need to be overcome if these systems are to be used as the fundamental components of an eventual quantum computer. One such hurdle is the relatively short coherence times these systems display which severely limits the amount of time quantum information can remain encoded within them. In this dissertation, recent experiments conducted with the intent of bringing this technology closer to realization are presented. The detailed knowledge of the spin Hamiltonian and mechanisms of decoherence in SMMs are absolutely essential if these systems are to be used in technologies. To that effect, experiments were done on a particularly promising SMM, the complex K6[VIV15AsIII 6O42(H2O)] · 8H2O, known as V15. High-field electron spin resonance (ESR) measurements were performed on this system at the National High Magnetic Field Laboratory. The resulting spectra allowed for detailed analysis of the V15 spin Hamiltonian which will be presented as well as the most precise values yet reported for the g-factors of this system. Additionally, the line widths of the ESR spectra are studied in depth and found to reveal that fluctuations within the spin-orbit interaction are a mechanism for decoherence in V15. A new model for decoherence is presented that describes very well both the temperature and field orientation dependences of the measured ESR line widths. Also essential is the ability to control spin-states of SMMs. Presented in this dissertation as well is the demonstration of the coherent manipulation of the multi-state spin system Mn2+ diluted in MgO by means of a two-tone pulse drive. Through the detuning between the excitation and readout radio frequency pulses it is possible to select the number of photons involved in a Rabi oscillation as well as increase

  8. Electron spin resonance in the study of diamond

    International Nuclear Information System (INIS)

    The role of electron spin resonance in the study of both natural and synthetic diamond is reviewed in this article. A brief survey of the physical significance of the constants in the spin Hamiltonian, as well as experimental technique, is given. The review then deals in some detail with the various nitrogen centres found in diamond, treating exchange-interaction, Jahn-Teller and relaxation effects associated with these centres. Acceptor impurities and transition-ion impurities are briefly discussed. The rest of the review is then devoted to centres created by irradiation, subsequent heat treatment, mechanical deformation and ion implantation. The spin Hamiltonian parameters of these centres are tabled and the results are discussed within the framework of the defect molecule approach. In conclusion, the correlation between optical effects and the ESR measurements in the case of four defect centres are discussed in some detail as this seems to be a powerful method of testing the various models suggested for the observed defects. It is hoped that the tables given of the observed centres found in diamond up to the present will be useful to researchers in this field. 155 references. (author)

  9. Direct-decay properties of charge-exchange spin giant resonances

    CERN Document Server

    Rodin, V A

    2001-01-01

    An extended continuum-RPA approach is applied to describe direct-decay properties of spin giant resonances in $^{208}$Bi and $^{90}$Nb. Partial branching ratios for direct proton decay from these resonances are evaluated. The branching ratio for $\\gamma$-decay from the spin-dipole resonance to the Gamow-Teller resonance (main peak) is estimated. The saturation-like behaviour of the mean doorway-state spreading width in $^{208}$Pb is discussed in connection with the branching ratio for direct proton decay from the spin-monopole resonance and the Gamow-Teller strength distribution.

  10. Spin-locked internally resonant ion cyclotron excitation for magnetic resonance trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Pizarro, P.J.; Weitekamp, D.P.

    1993-05-01

    We have recently proposed internally resonant ion cyclotron excitation (IRICE) as a tool for detecting the magnetic resonance (MR) spectra of trapped ions. A magnetic field gradient modulated at both the Larmor and cyclotron frequencies leads to cyclotron acceleration proportional to the transverse magnetic moment of a coherent state of the particle and radiation field. In the presence of a magnetic bottle, the resulting shift in the axial trapping frequency due to this spin-dependent work can be made much larger than the shift due directly to a spin flip. Our original proposal, however, was effective only for fields sharply resonant with the Larmor frequency, limiting its applicability primarily to cw MR experiments. For Fourier transform experiments, excitation of ion motion over the entire MR spectral width is desirable. FT experiments would require a large IRICE Larmor bandwidth. We present a spin-locked version of IRICE (SL-IRICE), where an additional magnetic field at the Larmor frequency is used to lock the transverse magnetic moment in phase with the IRICE field gradient. Illustrative experimental designs indicate that spectral widths sufficient for FT NMR experiments are practical. In the proposed experiment, the time evolution from a period of high-resolution precession modulates the probability of a net axial frequency shift between two detection periods. Quantum and semiclassical analyses of the excitation process agree quantitatively. Simulated signals including estimated noise illustrate the feasibility of the method.

  11. Spin-locked internally resonant ion cyclotron excitation for magnetic resonance trapped ions

    International Nuclear Information System (INIS)

    We have recently proposed internally resonant ion cyclotron excitation (IRICE) as a tool for detecting the magnetic resonance (MR) spectra of trapped ions. A magnetic field gradient modulated at both the Larmor and cyclotron frequencies leads to cyclotron acceleration proportional to the transverse magnetic moment of a coherent state of the particle and radiation field. In the presence of a magnetic bottle, the resulting shift in the axial trapping frequency due to this spin-dependent work can be made much larger than the shift due directly to a spin flip. Our original proposal, however, was effective only for fields sharply resonant with the Larmor frequency, limiting its applicability primarily to cw MR experiments. For Fourier transform experiments, excitation of ion motion over the entire MR spectral width is desirable. FT experiments would require a large IRICE Larmor bandwidth. We present a spin-locked version of IRICE (SL-IRICE), where an additional magnetic field at the Larmor frequency is used to lock the transverse magnetic moment in phase with the IRICE field gradient. Illustrative experimental designs indicate that spectral widths sufficient for FT NMR experiments are practical. In the proposed experiment, the time evolution from a period of high-resolution precession modulates the probability of a net axial frequency shift between two detection periods. Quantum and semiclassical analyses of the excitation process agree quantitatively. Simulated signals including estimated noise illustrate the feasibility of the method

  12. Electron Spin Resonance and Related Phenomena in Low-Dimensional Structures

    CERN Document Server

    Fanciulli, Marco

    2009-01-01

    Deals with the discussion of the development of spin resonance in low dimensional structures, such as two-dimensional electron systems, quantum wires, and quantum dots. This title discusses opportunities for spin resonance techniques, with emphasis on fundamental physics, nanoelectronics, spintronics, and quantum information processing

  13. Nuclear Tuning and Detuning of the Electron Spin Resonance in a Quantum Dot: Theoretical Consideration

    NARCIS (Netherlands)

    Danon, J.; Nazarov, Y.V.

    2008-01-01

    We study nuclear spin dynamics in a quantum dot close to the conditions of electron spin resonance. We show that at a small frequency mismatch, the nuclear field detunes the resonance. Remarkably, at larger frequency mismatch, its effect is opposite: The nuclear system is bistable, and in one of the

  14. Magnetic resonance force microscopy with a single spin S>1/2

    International Nuclear Information System (INIS)

    We studied theoretically detection of a single spin S>1/2 using magnetic resonance force microscopy (MRFM) and taking into account anisotropy. We have shown that the MRFM signal for a spin S>1/2 is the same as for spin S=1/2 and obtained the analytical estimate for the half-width of the signal.

  15. Identification of irradiated chicken meat using electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    Studies were carried out on detection of irradiation treatment in chicken using electron spin resonance (ESR) spectroscopy. The effect of gamma- irradiation treatment on radiation induced signal in different types of chicken namely, broiler, deshi and layers was studied. Irradiation treatment induced a characteristic ESR signal that was not detected in non-irradiated samples. The shape of the signal was not affected by type of the bone. The intensity of radiation induced ESR signal was affected by factors such as absorbed radiation dose, bone type irradiation temperature, post-irradiation storage, post-irradiation cooking and age of the bird. Deep-frying resulted in the formation of a symmetric signal that had a different shape and was weaker than the radiation induced signal. This technique can be effectively used to detect irradiation treatment in bone-in chicken meat even if stored and/or subjected to various traditional cooking procedures. (author)

  16. Electron spin resonance intercomparison studies on irradiated foodstuffs

    International Nuclear Information System (INIS)

    The results of intercomparison studies organized by the Community Bureau of Reference on the use of electron spin resonance spectroscopy for the identification of irradiated food are presented. A qualitative intercomparison was carried out using beef and trout bones, sardine scales, pistachio nut shells, dried grapes and papaya. A quantitative intercomparison involving the use of poultry bones was also organized. There was no difficulty in identifying meat bones, dried grapes and papaya. In the case of fish bones there is a need for further kinetic studies using different fish species. The identification of pistachio nut shells is more complicated and further research is needed prior to the organization of a further intercomparison. Laboratories were able to distinguish between chicken bones irradiated in the range 1 to 3 KGy or 7 to 10 KGy although there was a partial overlap between the results from different laboratories

  17. Electron Spin Resonance Imaging Utilizing Localized Microwave Magnetic Field

    Science.gov (United States)

    Furusawa, Masahiro; Ikeya, Motoji

    1990-02-01

    A method for two-dimensional electron spin resonance (ESR) imaging utilizing a localized microwave field is presented with an application of the image processing technique. Microwaves are localized at the surface of a sample by placing a sample in contact with a pinholed cavity wall. A two-dimensional ESR image can be obtained by scanning the sample in contact with the cavity. Some ESR images which correspond to distribution of natural radiation damages and paramagnetic impurities in carbonate fossils of a crinoid and an ammonite are presented as applications in earth science. Resolution of a raw ESR image is restricted by the diameter of the hole (1 mm). Higher resolution of 0.2 mm is obtained by using a deconvolution algorithm and instrument function for the hole. Restored images of a test sample of DPPH and of a fossil crinoid are presented.

  18. Ferromagnetic Resonance Spin Pumping and Electrical Spin Injection in Silicon-Based Metal-Oxide-Semiconductor Heterostructures

    Science.gov (United States)

    Pu, Y.; Odenthal, P. M.; Adur, R.; Beardsley, J.; Swartz, A. G.; Pelekhov, D. V.; Flatté, M. E.; Kawakami, R. K.; Pelz, J.; Hammel, P. C.; Johnston-Halperin, E.

    2015-12-01

    We present the measurement of ferromagnetic resonance (FMR-)driven spin pumping and three-terminal electrical spin injection within the same silicon-based device. Both effects manifest in a dc spin accumulation voltage Vs that is suppressed as an applied field is rotated to the out-of-plane direction, i.e., the oblique Hanle geometry. Comparison of Vs between these two spin injection mechanisms reveals an anomalously strong suppression of FMR-driven spin pumping with increasing out-of-plane field Happz . We propose that the presence of the large ac component to the spin current generated by the spin pumping approach, expected to exceed the dc value by 2 orders of magnitude, is the origin of this discrepancy through its influence on the spin dynamics at the oxide-silicon interface. This convolution, wherein the dynamics of both the injector and the interface play a significant role in the spin accumulation, represents a new regime for spin injection that is not well described by existing models of either FMR-driven spin pumping or electrical spin injection.

  19. Nucleon Spin Structure Functions in the Resonance Region and the Duality

    Institute of Scientific and Technical Information of China (English)

    DONG Yu-Bing; FENG Qing-Guo

    2003-01-01

    We discuss the nucleon spin structure function gl and the difference between the proton and neutrontargets gp1 - gn1 , based on quark model calculation. Quark-hadron duality for the nucleon spin structure function is alsoanalyzed. Effects of the △(1232) and Roper P11(1440) resonances on the spin structure function and on the differencegn1 - gn1 are mentioned. The results of different models for the Roper resonance are also addressed.

  20. Off-Resonant Manipulation of Spins in Diamond via Precessing Magnetization of a Proximal Ferromagnet

    OpenAIRE

    Wolfe, Chris. S.; Bhallamudi, Vidya P.; Wang, Hilong L.; Du, Chunhui H.; Manuilov, Sergei; Berger, Andrew J.; Adur, Rohan; Yang, Fengyuan Y.; Hammel, P. Chris

    2014-01-01

    We report the manipulation of nitrogen vacancy (NV) spins in diamond when nearby ferrimagnetic insulator, yttrium iron garnet, is driven into precession. The change in NV spin polarization, as measured by changes in photoluminescence, is comparable in magnitude to that from conventional optically detected magnetic resonance, but relies on a distinct mechanism as it occurs at a microwave frequency far removed from the magnetic resonance frequency of the NV spin. This observation presents a new...

  1. Light-free magnetic resonance force microscopy for studies of electron spin polarized systems

    International Nuclear Information System (INIS)

    Magnetic resonance force microscopy is a scanned probe technique capable of three-dimensional magnetic resonance imaging. Its excellent sensitivity opens the possibility for magnetic resonance studies of spin accumulation resulting from the injection of spin polarized currents into a para-magnetic collector. The method is based on mechanical detection of magnetic resonance which requires low noise detection of cantilever displacement; so far, this has been accomplished using optical interferometry. This is undesirable for experiments on doped silicon, where the presence of light is known to enhance spin relaxation rates. We report a non-optical displacement detection scheme based on sensitive microwave capacitive readout

  2. Spin Transfer of Quantum Information between Majorana Modes and a Resonator

    Science.gov (United States)

    Kovalev, Alexey A.; De, Amrit; Shtengel, Kirill

    2014-03-01

    We show that resonant coupling and entanglement between a mechanical resonator and Majorana bound states can be achieved via spin currents in a 1D quantum wire with strong spin-orbit interactions. The bound states induced by vibrating and stationary magnets can hybridize, thus resulting in spin-current induced 4π-periodic torques, as a function of the relative field angle, acting on the resonator. We study the feasibility of detecting and manipulating Majorana bound states with the use of magnetic resonance force microscopy techniques.

  3. Hydrogen in group III nitrides, studied by muon spin resonance

    International Nuclear Information System (INIS)

    This paper reviews recent work on the properties of hydrogen defect centres in two group III nitrides, AlN and GaN, and relevant studies by μSR spectroscopy, i.e. muon spin rotation, relaxation and resonance. We highlight, especially, results obtained by a form of nuclear quadrupole resonance. Implanted positive muons are used to mimic and model the behaviour of interstitial protons. The resultant defect centres exhibit both metastability and bistability. In AlN, they remain as positive ions but partition themselves between a highly mobile species and one that is trapped and immobilized to temperatures as high as 800 K in cage-like sites adjacent to nitrogen. The barrier to escape from the cage is 0.86 eV. In n-type GaN, the cage-site positive ions are stable only up to 200 K; above this temperature they capture electrons to convert to negatively charged centres, analogues of hydride ions, relocating to sites antibonding to gallium. These latter escape from the cage sites around 600 K with an activation energy of 1.5 eV to join more mobile negative ions diffusing via channel sites with an activation energy of 0.65 eV. Data on the neutral paramagnetic centre suggest that hydrogen can act as a shallow-donor in at least one other member of this family of materials, namely InN. (author)

  4. Controlling the Spin Polarization of the Electron Current in a Semimagnetic Resonant-Tunneling Diode

    OpenAIRE

    Beletskii, N. N.; Berman, G. P.; Borysenko, S. A.

    2004-01-01

    The spin filtering effect of the electron current in a double-barrier resonant-tunneling diode (RTD) consisting of ZnMnSe semimagnetic layers has been studied theoretically. The influence of the distribution of the magnesium ions on the coefficient of the spin polarization of the electron current has been investigated. The dependence of the spin filtering degree of the electron current on the external magnetic field and the bias voltage has been obtained. The effect of the total spin polariza...

  5. Study of f electron correlations in nonmagnetic Ce by means of spin resolved resonant photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S; Komesu, T; Chung, B W; Waddill, G D; Morton, S A; Tobin, J G

    2005-11-28

    We have studied the spin-spin coupling between two f electrons of nonmagnetic Ce by means of spin resolved resonant photoemission using circularly polarized synchrotron radiation. The two f electrons participating in the 3d{sub 5/2} {yields} 4f resonance process are coupled in a singlet while the coupling is veiled in the 3d{sub 3/2} {yields} 4f process due to an additional Coster-Kronig decay channel. The identical singlet coupling is observed in the 4d {yields} 4f resonance process. Based on the Ce measurements, it is argued that spin resolved resonant photoemission is a unique approach to study the correlation effects, particularly in the form of spin, in the rare-earths and the actinides.

  6. Atomic-resolution single-spin magnetic resonance detection concept based on tunneling force microscopy

    Science.gov (United States)

    Payne, A.; Ambal, K.; Boehme, C.; Williams, C. C.

    2015-05-01

    A study of a force detected single-spin magnetic resonance measurement concept with atomic spatial resolution is presented. The method is based upon electrostatic force detection of spin-selection rule controlled single-electron tunneling between two electrically isolated paramagnetic states. Single-spin magnetic resonance detection is possible by measuring the force detected tunneling charge noise on and off spin resonance. Simulation results of this charge noise, based upon physical models of the tunneling and spin physics, are directly compared to measured atomic force microscopy system noise. The results show that the approach could provide single-spin measurement of electrically isolated qubit states with atomic spatial resolution at room temperature.

  7. Disentangling the Spin-Parity of a Resonance via the Gold-Plated Decay Mode

    CERN Document Server

    Modak, Tanmoy; Sinha, Rahul; Cheng, Hai-Yang; Yuan, Tzu-Chiang

    2014-01-01

    Searching for new resonances and finding out their properties is an essential part of any existing or future particle physics experiment. The nature of a new resonance is characterized by its spin, charge conjugation, parity, and its couplings with the existing particles of the Standard Model. If a new resonance is found in the four lepton final state produced via two intermediate $Z$ bosons, the resonance could be a new heavy scalar or a $Z'$ boson or even a higher spin particle. In such cases the step by step methodology as enunciated in this paper can be followed to determine the spin, parity and the coupling to two $Z$ bosons of the parent particles, in a fully model-independent way. In our approach we show how three uni-angular distributions and few experimentally measurable observables can conclusively tell us about the spin, parity as well as the couplings of the new resonance to two $Z$ bosons.

  8. Detection of single electron spin resonance in a double quantum dota)

    Science.gov (United States)

    Koppens, F. H. L.; Buizert, C.; Vink, I. T.; Nowack, K. C.; Meunier, T.; Kouwenhoven, L. P.; Vandersypen, L. M. K.

    2007-04-01

    Spin-dependent transport measurements through a double quantum dot are a valuable tool for detecting both the coherent evolution of the spin state of a single electron, as well as the hybridization of two-electron spin states. In this article, we discuss a model that describes the transport cycle in this regime, including the effects of an oscillating magnetic field (causing electron spin resonance) and the effective nuclear fields on the spin states in the two dots. We numerically calculate the current flow due to the induced spin flips via electron spin resonance, and we study the detector efficiency for a range of parameters. The experimental data are compared with the model and we find a reasonable agreement.

  9. Detection of nanoscale electron spin resonance spectra demonstrated using nitrogen-vacancy centre probes in diamond

    Science.gov (United States)

    Hall, L. T.; Kehayias, P.; Simpson, D. A.; Jarmola, A.; Stacey, A.; Budker, D.; Hollenberg, L. C. L.

    2016-01-01

    Electron spin resonance (ESR) describes a suite of techniques for characterizing electronic systems with applications in physics, chemistry, and biology. However, the requirement for large electron spin ensembles in conventional ESR techniques limits their spatial resolution. Here we present a method for measuring ESR spectra of nanoscale electronic environments by measuring the longitudinal relaxation time of a single-spin probe as it is systematically tuned into resonance with the target electronic system. As a proof of concept, we extracted the spectral distribution for the P1 electronic spin bath in diamond by using an ensemble of nitrogen-vacancy centres, and demonstrated excellent agreement with theoretical expectations. As the response of each nitrogen-vacancy spin in this experiment is dominated by a single P1 spin at a mean distance of 2.7 nm, the application of this technique to the single nitrogen-vacancy case will enable nanoscale ESR spectroscopy of atomic and molecular spin systems.

  10. Identification of irradiated rice noodles by electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) spectroscopy has been applied to the identification of the irradiation of a wide variety of foods. In this study, ESR was applied to identify irradiated rice noodles. A detailed ESR investigation of irradiated noodles was carried out in the dose range 0.5–3 kGy. The stability of the radiation-induced ESR signal at cold (−4 °C) and room (25 °C) temperatures was studied over a storage period of 24 weeks. Irradiated rice noodle samples exhibited a strong, symmetric doublet ESR signal centered at g = 2.0, whereas unirradiated noodle exhibited a very weak signal. The ESR signal intensity increased linearly with radiation dose ranging from 0.5 to 3 kGy. Keeping the samples at −4 °C and 25 °C for 24 weeks caused decreases of 50% and 90% in the ESR signal intensities, respectively. However, long-term decay data at room temperature showed that the ESR technique could be used to identify irradiated rice noodles up to 24 weeks following irradiation.

  11. Mechanical detection of electron spin resonance beyond 1 THz

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hideyuki [Organization of Advanced Science and Technology, Kobe University, 1-1, Rokkodai, Nada, Kobe 657-8501 (Japan); Ohmichi, Eiji [Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan); Ohta, Hitoshi [Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan)

    2015-11-02

    We report the cantilever detection of electron spin resonance (ESR) in the terahertz (THz) region. This technique mechanically detects ESR as a change in magnetic torque that acts on the cantilever. The ESR absorption of a tiny single crystal of Co Tutton salt, Co(NH{sub 4}){sub 2}(SO{sub 4}){sub 2}⋅6H{sub 2}O, was observed in frequencies of up to 1.1 THz using a backward travelling wave oscillator as a THz-wave source. This is the highest frequency of mechanical detection of ESR till date. The spectral resolution was evaluated with the ratio of the peak separation to the sum of the half-width at half maximum of two absorption peaks. The highest resolution value of 8.59 ± 0.53 was achieved at 685 GHz, while 2.47 ± 0.01 at 80 GHz. This technique will not only broaden the scope of ESR spectroscopy application but also lead to high-spectral-resolution ESR imaging.

  12. Multipartite Spin Entangled States in Quantum Dots with a Quantum Databus Based on Nano Electro-Mechanical Resonator

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhi-Cheng; TU Tao; GUO Guo-Ping

    2011-01-01

    We propose an efficient method to create multipartite spin entangled states in quantum dots coupled to a nano electro-mechanical resonator array. Our method, based on the interaction between electron spins confined in quantum dots and the motion of magnetized nano electro-mechanical resonators, can enable a coherent spin-spin coupling over long distances and in principle be applied to an arbitrarily large number of electronic spins.%@@ We propose an efficient method to create multipartite spin entangled states in quantum dots coupled to a nano electro-mechanical resonator array.Our method, based on the interaction between electron spins confined in quantum dots and the motion of magnetized nano electro-mechanical resonators, can enable a coherent spin-spin coupling over long distances and in principle be applied to an arbitrarily large number of electronic spins.

  13. Spin-dependent current in resonant tunneling diode with ferromagnetic GaMnN layers

    International Nuclear Information System (INIS)

    The spin-polarized tunneling current through a double barrier resonant tunneling diode (RTD) with ferromagnetic GaMnN emitter/collector is investigated theoretically. Two distinct spin splitting peaks can be observed at current-voltage (I-V) characteristics at low temperature. The spin polarization decreases with the temperature due to the thermal effect of electron density of states. When charge polarization effect is considered at the heterostructure, the spin polarization is enhanced significantly. A highly spin-polarized current can be obtained depending on the polarization charge density.

  14. Spin-dependent current in resonant tunneling diode with ferromagnetic GaMnN layers

    Energy Technology Data Exchange (ETDEWEB)

    Tang, N.Y. [Shanghai University of Electric Power, Shanghai 200090 (China)], E-mail: naiyuntang@126.com

    2009-08-15

    The spin-polarized tunneling current through a double barrier resonant tunneling diode (RTD) with ferromagnetic GaMnN emitter/collector is investigated theoretically. Two distinct spin splitting peaks can be observed at current-voltage (I-V) characteristics at low temperature. The spin polarization decreases with the temperature due to the thermal effect of electron density of states. When charge polarization effect is considered at the heterostructure, the spin polarization is enhanced significantly. A highly spin-polarized current can be obtained depending on the polarization charge density.

  15. Induction-Detection Electron Spin Resonance with Sensitivity of 1000 Spins: En Route to Scalable Quantum Computations

    CERN Document Server

    Blank, Aharon; Shklyar, Roman; Twig, Ygal

    2013-01-01

    Spin-based quantum computation (QC) in the solid state is considered to be one of the most promising approaches to scalable quantum computers. However, it faces problems such as initializing the spins, selectively addressing and manipulating single spins, and reading out the state of the individual spins. We have recently sketched a scheme that potentially solves all of these problems5. This is achieved by making use of a unique phosphorus-doped 28Si sample (28Si:P), and applying powerful new electron spin resonance (ESR) techniques for parallel excitation, detection, and imaging in order to implement QCs and efficiently obtain their results. The beauty of our proposed scheme is that, contrary to other approaches, single-spin detection sensitivity is not required and a capability to measure signals of ~100-1000 spins is sufficient to implement it. Here we take the first experimental step towards the actual implementation of such scheme. We show that, by making use of the smallest ESR resonator constructed to ...

  16. Electron Spin Resonance of Tetrahedral Transition Metal Oxyanions (MO4n-) in Solids.

    Science.gov (United States)

    Greenblatt, M.

    1980-01-01

    Outlines general principles in observing sharp electron spin resonance (ESR) lines in the solid state by incorporating the transition metal ion of interest into an isostructural diamagnetic host material in small concentration. Examples of some recent studies are described. (CS)

  17. Multipartite Spin Entangled States in Quantum Dots with a Quantum Databus Based on Nano Electro-Mechanical Resonator

    International Nuclear Information System (INIS)

    We propose an efficient method to create multipartite spin entangled states in quantum dots coupled to a nano electro-mechanical resonator array. Our method, based on the interaction between electron spins confined in quantum dots and the motion of magnetized nano electro-mechanical resonators, can enable a coherent spin-spin coupling over long distances and in principle be applied to an arbitrarily large number of electronic spins. (general)

  18. Effects of the electron-electron interaction in the spin resonance in 2D systems with Dresselhaus spin-orbit coupling

    Energy Technology Data Exchange (ETDEWEB)

    Krishtopenko, S. S., E-mail: sergey.krishtopenko@mail.ru [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

    2015-02-15

    The effect of the electron-electron interaction on the spin-resonance frequency in two-dimensional electron systems with Dresselhaus spin-orbit coupling is investigated. The oscillatory dependence of many-body corrections on the magnetic field is demonstrated. It is shown that the consideration of many-body interaction leads to a decrease or an increase in the spin-resonance frequency, depending on the sign of the g factor. It is found that the term cubic in quasimomentum in Dresselhaus spin-orbit coupling partially decreases exchange corrections to the spin resonance energy in a two-dimensional system.

  19. Driving and detecting ferromagnetic resonance in insulators with the spin Hall effect.

    Energy Technology Data Exchange (ETDEWEB)

    Sklenar, Joseph; Zhang, Wei; Jungfleisch, Matthias B.; Jiang, Wanjun; Chang, Houchen; Pearson, John E.; Wu, Mingzhong; Ketterson, John B.; Hoffmann, Axel

    2015-11-06

    We demonstrate the generation and detection of spin-torque ferromagnetic resonance in Pt/Y3Fe5O12 (YIG) bilayers. A unique attribute of this system is that the spin Hall effect lies at the heart of both the generation and detection processes and no charge current is passing through the insulating magnetic layer. When the YIG undergoes resonance, a dc voltage is detected longitudinally along the Pt that can be described by two components. One is the mixing of the spin Hall magnetoresistance with the microwave current. The other results from spin pumping into the Pt being converted to a dc current through the inverse spin Hall effect. The voltage is measured with applied magnetic field directions that range in-plane to nearly perpendicular. We find that for magnetic fields that are mostly out-of-plane, an imaginary component of the spin mixing conductance is required to model our data.

  20. Voltage-Controlled Spin Selection in a Magnetic Resonant Tunnelling Diode

    OpenAIRE

    Slobodskyy, A.; Gould, C.; Slobodskyy, T.; Becker, C.R.; Schmidt, G.; Molenkamp, L.W.

    2003-01-01

    We have fabricated all II-VI semiconductor resonant tunneling diodes based on the (Zn,Mn,Be)Se material system, containing dilute magnetic material in the quantum well, and studied their current-voltage characteristics. When subjected to an external magnetic field the resulting spin splitting of the levels in the quantum well leads to a splitting of the transmission resonance into two separate peaks. This is interpreted as evidence of tunneling transport through spin polarized levels, and cou...

  1. Resonant Neutrino Spin-Flavor Precession and Supernova Nucleosynthesis and Dynamics

    CERN Document Server

    Nunokawa, H; Fuller, G M

    1997-01-01

    We discuss the effects of resonant spin-flavor precession (RSFP) of Majorana neutrinos on heavy element nucleosynthesis in neutrino-heated supernova ejecta and the dynamics of supernovae. In assessing the effects of RSFP, we explicitly include matter-enhanced (MSW) resonant neutrino flavor conversion effects where appropriate. We point out that for plausible ranges of neutrino magnetic moments and proto-neutron star magnetic fields, spin-flavor conversion of into a light $\\bar \

  2. Using Markov models to simulate electron spin resonance spectra from molecular dynamics trajectories

    OpenAIRE

    Sezer, Deniz; Freed, Jack H.; Roux, Benoît

    2008-01-01

    Simulating electron spin resonance (ESR) spectra directly from molecular dynamics simulations of a spin labeled protein necessitates a large number (hundreds or thousands) of relatively long (hundreds of ns) trajectories. To meet this challenge, we explore the possibility of constructing accurate stochastic models of the spin label dynamics from atomistic trajectories. A systematic, two-step procedure, based on the probabilistic framework of hidden Markov models, is developed to build a discr...

  3. Sealed magic angle spinning nuclear magnetic resonance probe and process for spectroscopy of hazardous samples

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Herman M.; Washton, Nancy M.; Mueller, Karl T.; Sears, Jr., Jesse A.; Townsend, Mark R.; Ewing, James R.

    2016-06-14

    A magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) probe is described that includes double containment enclosures configured to seal and contain hazardous samples for analysis. The probe is of a modular design that ensures containment of hazardous samples during sample analysis while preserving spin speeds for superior NMR performance and convenience of operation.

  4. Measurement of the Spin of the $\\Xi(1530)$ Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prudent, X.; Tisserand, V.; Zghiche, A.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Lopez, L.; Palano, A.; Pappagallo, M.; /Bari U. /INFN, Bari; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Abrams, G.S.; Battaglia, M.; Brown, D.N.; Button-Shafer, J.; Cahn, R.N.; /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /INFN, Ferrara /Frascati /Genoa U. /INFN, Genoa /Harvard U. /Heidelberg U. /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Karlsruhe U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /Naples U. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /Padua U. /INFN, Padua /Paris U., VI-VII /Pennsylvania U. /Perugia U. /INFN, Perugia /Pisa U. /Pisa, Scuola Normale Superiore /INFN, Pisa /Princeton U. /Rome U. /INFN, Rome /Rostock U. /Rutherford /DSM, DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Albany /Tennessee U. /Texas U. /Texas U., Dallas /Turin U. /INFN, Turin /Trieste U. /INFN, Trieste /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison

    2008-03-25

    The properties of the {Xi}(1530) resonance are investigated in the {Lambda}{sub c}{sup +} {yields} {Xi}{sup -}{pi}{sup +}K{sup +} decay process. The data sample was collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e{sup +}e{sup -} collider operating at center of mass energies 10.58 and 10.54 GeV. The corresponding integrated luminosity is approximately 230 fb{sup -1}. The spin of the {Xi}(1530) is established to be 3/2. The existence of an S-wave amplitude in the {Xi}{sup -}{pi}{sup +} system is inferred, and its interference with the {Xi}(1530)0 amplitude provides the first clear demonstration of the Breit-Wigner phase motion expected for the {Xi}(1530). The P{sub 1}(cos {theta}{sub {Xi}{sup -}}) Legendre polynomial moment indicates the presence of a significant S-wave amplitude for {Xi}{sup -}{pi}{sup +} mass values above 1.6 GeV/c{sup 2}, and a dip in the mass distribution at approximately 1.7 GeV/c{sup 2} is interpreted as due to coherent addition of a {Xi}(1690){sup 0} contribution to this amplitude. This would imply J{sup P} = 1/2{sup -} for the {Xi}(1690). Attempts at fitting the {Xi}(1530){sup 0} lineshape yield unsatisfactory results, and this failure is attributed to interference effects associated with the amplitudes describing the K{sup +}{pi}{sup +} and/or {Xi}{sup -}K{sup +} systems.

  5. Energy harvesting using rattleback: Theoretical analysis and simulations of spin resonance

    Science.gov (United States)

    Nanda, Aditya; Singla, Puneet; Karami, M. Amin

    2016-05-01

    This paper investigates the spin resonance of a rattleback subjected to base oscillations which is able to transduce vibrations into continuous rotary motion and, therefore, is ideal for applications in Energy harvesting and Vibration sensing. The rattleback is a toy with some curious properties. When placed on a surface with reasonable friction, the rattleback has a preferred direction of spin. If rotated anti to it, longitudinal vibrations are set up and spin direction is reversed. In this paper, the dynamics of a rattleback placed on a sinusoidally vibrating platform are simulated. We can expect base vibrations to excite the pitch motion of the rattleback, which, because of the coupling between pitch and spin motion, should cause the rattleback to spin. Results are presented which show that this indeed is the case-the rattleback has a mono-peak spin resonance with respect to base vibrations. The dynamic response of the rattleback was found to be composed of two principal frequencies that appeared in the pitch and rolling motions. One of the frequencies was found to have a large coupling with the spin of the rattleback. Spin resonance was found to occur when the base oscillatory frequency was twice the value of the coupled frequency. A linearized model is developed which can predict the values of the two frequencies accurately and analytical expressions for the same in terms of the parameters of the rattleback have been derived. The analysis, thus, forms an effective and easy method for obtaining the spin resonant frequency of a given rattleback. Novel ideas for applications utilizing the phenomenon of spin resonance, for example, an energy harvester composed of a magnetized rattleback surrounded by ferromagnetic walls and a small scale vibration sensor comprising an array of several magnetized rattlebacks, are included.

  6. Quantum Measurement of a Single Spin using Magnetic Resonance Force Microscopy

    CERN Document Server

    Berman, G P; Chapline, G; Gurvitz, S A; Hammel, P C; Pelekhov, D V; Suter, A; Tsifrinovich, V I

    2003-01-01

    Single-spin detection is one of the important challenges facing the development of several new technologies, e.g. single-spin transistors and solid-state quantum computation. Magnetic resonance force microscopy with a cyclic adiabatic inversion, which utilizes a cantilever oscillations driven by a single spin, is a promising technique to solve this problem. We have studied the quantum dynamics of a single spin interacting with a quasiclassical cantilever. It was found that in a similar fashion to the Stern-Gerlach interferometer the quantum dynamics generates a quantum superposition of two quasiclassical trajectories of the cantilever which are related to the two spin projections on the direction of the effective magnetic field in the rotating reference frame. Our results show that quantum jumps will not prevent a single-spin measurement if the coupling between the cantilever vibrations and the spin is small in comparison with the amplitude of the radio-frequency external field.

  7. Voltage-controlled spin selection in a magnetic resonant tunneling diode.

    Science.gov (United States)

    Slobodskyy, A; Gould, C; Slobodskyy, T; Becker, C R; Schmidt, G; Molenkamp, L W

    2003-06-20

    We have fabricated all II-VI semiconductor resonant tunneling diodes based on the (Zn,Mn,Be)Se material system, containing dilute magnetic material in the quantum well, and studied their current-voltage characteristics. When subjected to an external magnetic field the resulting spin splitting of the levels in the quantum well leads to a splitting of the transmission resonance into two separate peaks. This is interpreted as evidence of tunneling transport through spin polarized levels, and could be the first step towards a voltage controlled spin filter. PMID:12857209

  8. Phonon-magnon resonant processes with relevance to acoustic spin pumping

    KAUST Repository

    Deymier, P. A.

    2014-12-23

    The recently described phenomenon of resonant acoustic spin pumping is due to resonant coupling between an incident elastic wave and spin waves in a ferromagnetic medium. A classical one-dimensional discrete model of a ferromagnet with two forms of magnetoelastic coupling is treated to shed light on the conditions for resonance between phonons and magnons. Nonlinear phonon-magnon interactions in the case of a coupling restricted to diagonal terms in the components of the spin degrees of freedom are analyzed within the framework of the multiple timescale perturbation theory. In that case, one-phonon-two-magnon resonances are the dominant mechanism for pumping. The effect of coupling on the dispersion relations depends on the square of the amplitude of the phonon and magnon excitations. A straightforward analysis of a linear phonon-magnon interaction in the case of a magnetoelastic coupling restricted to off-diagonal terms in the components of the spins shows a one-phonon to one-magnon resonance as the pumping mechanism. The resonant dispersion relations are independent of the amplitude of the waves. In both cases, when an elastic wave with a fixed frequency is used to stimulate magnons, application of an external magnetic field can be used to approach resonant conditions. Both resonance conditions exhibit the same type of dependency on the strength of an applied magnetic field.

  9. Resonant Scattering off Magnetic Impurities in Graphene: Mechanism for Ultrafast Spin Relaxation

    Science.gov (United States)

    Kochan, D.; Gmitra, M.; Fabian, J.

    We give a tutorial account of our recently proposed mechanism for spin relaxation based on spin-flip resonant scattering off local magnetic moments. The mechanism is rather general, working in any material with a resonant local moment, but we believe that its particular niche is graphene, whose measured spin relaxation time is 100-1000 ps. Conventional spin-orbit coupling based mechanisms (Elliott-Yafet or Dyakonov-Perel) would require large concentrations (1000 ppm) of impurities to explain this. Our mechanism needs only 1 ppm of resonant local moments, as these act as local spin hot spots: the resonant scatterers do not appear to substantially affect graphene's measured resistivity, but are dominating spin relaxation. In principle, the local moments can come from a variety of sources. Most likely would be organic molecule adsorbants or metallic adatoms. As the representative model, particularly suited for a tutorial, we consider hydrogen adatoms which are theoretically and experimentally demonstrated to yield local magnetic moments when chemisorbed on graphene. We introduce the scattering formalism and apply it to graphene, to obtain the T-matrix and spin-flip scattering rates using the generalized Fermi golden rule.

  10. Efficient rotational echo double resonance recoupling of a spin-1/2 and a quadrupolar spin at high spinning rates and weak irradiation fields

    Science.gov (United States)

    Nimerovsky, Evgeny; Goldbourt, Amir

    2010-09-01

    A modification of the rotational echo (adiabatic passage) double resonance experiments, which allows recoupling of the dipolar interaction between a spin-1/2 and a half integer quadrupolar spin is proposed. We demonstrate efficient and uniform recoupling at high spinning rates ( ν r), low radio-frequency (RF) irradiation fields ( ν1), and high values of the quadrupolar interaction ( ν q) that correspond to values of α=ν12/νqνr, the adiabaticity parameter, which are down to less than 10% of the traditional adiabaticity limit for a spin-5/2 (α = 0.55). The low-alpha rotational echo double resonance curve is obtained when the pulse on the quadrupolar nucleus is extended to full two rotor periods and beyond. For protons (spin-1/2) and aluminum (spin-5/2) species in the zeolite SAPO-42, a dephasing curve, which is significantly better than the regular REAPDOR experiment (pulse length of one-third of the rotor period) is obtained for a spinning rate of 13 kHz and RF fields down to 10 and even 6 kHz. Under these conditions, α is estimated to be approximately 0.05 based on an average quadrupolar coupling in zeolites. Extensive simulations support our observations suggesting the method to be robust under a large range of experimental values.

  11. Baseband Detection of Bistatic Electron Spin Signals in Magnetic Resonance Force Microscopy (MRFM)

    CERN Document Server

    Yip, C; Rugar, D; Fessler, J A; Yip, Chun-yu; Hero, Alfred O.; Rugar, Daniel; Fessler, Jeffrey A.

    2003-01-01

    In single spin Magnetic Resonance Force Microscopy (MRFM), the objective is to detect the presence of an electron (or nuclear) spin in a sample volume by measuring spin-induced attonewton forces using a micromachined cantilever. In the OSCAR method of single spin MRFM, the spins are manipulated by an external rf field to produce small periodic deviations in the resonant frequency of the cantilever. These deviations can be detected by frequency demodulation followed by conventional amplitude or energy detection. In this paper, we present an alternative to these detection methods, based on optimal detection theory and Gibbs sampling. On the basis of simulations, we show that our detector outperforms the conventional amplitude and energy detectors for realistic MRFM operating conditions. For example, to achieve a 10% false alarm rate and an 80% correct detection rate our detector has an 8 dB SNR advantage as compared with the conventional amplitude or energy detectors. Furthermore, at these detection rates it co...

  12. Spin-filter device based on the Rashba effect using a nonmagnetic resonant tunneling diode.

    Science.gov (United States)

    Koga, Takaaki; Nitta, Junsaku; Takayanagi, Hideaki; Datta, Supriyo

    2002-03-25

    We propose an electronic spin-filter device that uses a nonmagnetic triple barrier resonant tunneling diode (TB-RTD). This device combines the spin-split resonant tunneling levels induced by the Rashba spin-orbit interaction and the spin blockade phenomena between two regions separated by the middle barrier in the TB-RTD. Detailed calculations using the InAlAs/InGaAs material system reveal that a splitting of a peak should be observed in the I-V curve of this device as a result of the spin-filtering effect. The filtering efficiency exceeds 99.9% at the peak positions in the I-V curve. PMID:11909487

  13. Observation of vacuum-enhanced electron spin resonance of levitated nanodiamonds

    CERN Document Server

    Hoang, Thai M; Bang, Jaehoon; Li, Tongcang

    2015-01-01

    Electron spins of diamond nitrogen-vacancy (NV) centers are important quantum resources for nanoscale sensing and quantum information. Combining such NV spin systems with levitated optomechanical resonators will provide a hybrid quantum system for many novel applications. Here we optically levitate a nanodiamond and demonstrate electron spin control of its built-in NV centers in low vacuum. We observe that the strength of electron spin resonance (ESR) is enhanced when the air pressure is reduced. To better understand this novel system, we also investigate the effects of trap power and measure the absolute internal temperature of levitated nanodiamonds with ESR after calibration of the strain effect. Our results show that optical levitation of nanodiamonds in vacuum not only can improve the mechanical quality of its oscillation, but also enhance the ESR contrast, which pave the way towards a novel levitated spin-optomechanical system for studying macroscopic quantum mechanics. The results also indicate potenti...

  14. Measurement of a mixed-spin-channel Feshbach resonance in 87 Rb

    Science.gov (United States)

    Erhard, M.; Schmaljohann, H.; Kronjäger, J.; Bongs, K.; Sengstock, K.

    2004-03-01

    We report on the observation of a mixed-spin-channel Feshbach resonance at the low magnetic field value of 9.09±0.01 G for a mixture of ∣ 2,-1 > and ∣ 1,+1 > states in 87 Rb . This mixture is important for applications of multicomponent Bose-Einstein condensates of 87 Rb , e.g., in spin mixture physics and for quantum entanglement. Values for position, height, and width of the resonance are reported and compared to a recent theoretical calculation of this resonance.

  15. Current-induced resonant depinning of a transverse magnetic domain wall in a spin valve nanostrip

    Science.gov (United States)

    Metaxas, P. J.; Anane, A.; Cros, V.; Grollier, J.; Deranlot, C.; Lemaître, Y.; Xavier, S.; Ulysse, C.; Faini, G.; Petroff, F.; Fert, A.

    2010-11-01

    We study the impact of rf and dc currents on domain wall depinning in the soft layer of a 120 nm wide Co/Cu/NiFe spin valve nanostrip. A strong resonant reduction in the depinning field (from ˜75 to 25 Oe) is observed for rf currents near 3.5 GHz. Notably, the features of the resonant depinning depend not only on the rf current but also on the simultaneously applied dc current. Consequently, we discuss both the role of the adiabatic spin torque at resonance and that of the current generated Oersted fields.

  16. Intrinsic oscillations of spin current polarization in a paramagnetic resonant tunneling diode

    OpenAIRE

    Wojcik, Pawel; Adamowski, Janusz; Woloszyn, Maciej; Spisak, Bartlomiej J.

    2012-01-01

    A spin- and time-dependent electron transport has been studied in a paramagnetic resonant tunneling diode using the self-consistent Wigner-Poisson method. Based on the calculated current-voltage characteristics in an external magnetic field we have demonstrated that under a constant bias both the spin-up and spin-down current components exhibit the THz oscillations in two different bias voltage regimes. We have shown that the oscillations of the spin-up (down) polarized current result from th...

  17. Effect of current hysteresis on the spin polarization of current in a paramagnetic resonant tunneling diode

    OpenAIRE

    Wojcik, P.; Spisak, B. J.; Woloszyn, M.; J. Adamowski

    2011-01-01

    A spin-dependent quantum transport is investigated in a paramagnetic resonant tunneling diode (RTD) based on a Zn$_{1-x}$Mn$_x$Se/ZnBeSe heterostructure. Using the Wigner-Poisson method and assuming the two-current model we have calculated the current-voltage characteristics, potential energy profiles and electron density distributions for spin-up and spin-down electron current in an external magnetic field. We have found that -- for both the spin-polarized currents -- two types of the curren...

  18. Quantum size effects on spin-tunneling time in a magnetic resonant tunneling diode

    OpenAIRE

    Saffarzadeh, Alireza; Daqiq, Reza

    2009-01-01

    We study theoretically the quantum size effects of a magnetic resonant tunneling diode (RTD) with a (Zn,Mn)Se dilute magnetic semiconductor layer on the spin-tunneling time and the spin polarization of the electrons. The results show that the spin-tunneling times may oscillate and a great difference between the tunneling time of the electrons with opposite spin directions can be obtained depending on the system parameters. We also study the effect of structural asymmetry which is related to t...

  19. The quantum mechanics correspondence principle for spin systems and its application for some magnetic resonance problems

    CERN Document Server

    Henner, Victor; Belozerova, Tatyana

    2015-01-01

    Problems of interacting quantum magnetic moments become exponentially complex with increasing number of particles. As a result, classical equations are often used but the validity of reduction of a quantum problem to a classical problem should be justified. In this paper we formulate the correspondence principle, which shows that the classical equations of motion for a system of dipole interacting spins have identical form with the quantum equations. The classical simulations based on the correspondence principle for spin systems provide a practical tool to study different macroscopic spin physics phenomena. Three classical magnetic resonance problems in solids are considered as examples - free induction decay (FID), spin echo and the Pake doublet.

  20. Current-Induced Spin-Torque Resonance of Magnetic Insulators

    NARCIS (Netherlands)

    Chiba, T.; Bauer, G.E.W.; Takahashi, S.

    2014-01-01

    We formulate a theory of the ac spin Hall magnetoresistance in a bilayer system consisting of a magnetic insulator such as yttrium iron garnet and a heavy metal such as platinum. We derive expressions for the dc voltage generation based on the drift-diffusion spin model and quantum mechanical bounda

  1. Radiosterilization dosimetry by electron-spin resonance spectroscopy. Cefotetan

    Energy Technology Data Exchange (ETDEWEB)

    Basly, J.P.; Longy, I. [Laboratoire de Chimie Analytique et Bromatologie, UFR de Pharmacie, Limoges (France); Bernard, M. [Laboratoire de Physique et Biophysique Pharmaceutique, UFR de Pharmacie, Limoges (France)

    1998-02-19

    As an alternative to heat and gas exposure sterilization, ionizing radiation is gaining interest as a sterilization process for medicinal products. Nevertheless, essentially for economic profit, unauthorized and uncontrolled use of radiation processes may be expected. In this context, it is necessary to find methods of distinguishing between irradiated and nonirradiated pharmaceuticals. In the absence of suitable detection methods, our attention was focused on electron-spin resonance (ESR) spectrometry. A third generation cephalosporin, cefotetan, was chosen as a model; this antibiotic is a potential candidate for radiation treatment due to its thermosensitivity. While the ESR spectra of a nonirradiated sample presents no signal, a nonsymmetrical signal, dependent on the irradiation dose, is found in irradiated samples. The number of free radicals was estimated by comparing the second integral from radiosterilized samples and a diphenylpicryl hydrazyl reference. Estimation of the number of free radicals gives 7x10{sup 17} radicals g{sup -1} at 20kGy (1.1x10{sup 16} radicals in 15mg). From this result, the G-value (number of radicals (100eV){sup -1}) could be estimated as 0.6. Decay of radicals upon storage were modeled using a bi-exponential function. The limit of detection of free radicals after irradiation at 25kGy is up to two years. This result agrees with those obtained on other cephalosporins. Aside from qualitative detection, ESR spectrometry can be used for dose estimation. Linear regression is applicable for doses lower than 20kGy. Since the radiation dose selected must always be based upon the bioburden of the products and the degree of sterility required (EN 552 and ANSI/AAMI/ISO 11137), 25kGy could no longer be accepted as a `routine` dose for sterilizing a pharmaceutical. Doses in the 5-20kGy range could be investigated and linear regression appeared to be the least expensive route to follow. The best results for the integration of the curves were

  2. Probing dynamics of a spin ensemble of P1 centers in diamond using a superconducting resonator

    Science.gov (United States)

    de Lange, Gijs; Ranjan, Vishal; Schutjens, Ron; Debelhoir, Thibault; Groen, Joost; Szombati, Daniel; Thoen, David; Klapwijk, Teun; Hanson, Ronald; Dicarlo, Leonardo

    2013-03-01

    Solid-state spin ensembles are promising candidates for realizing a quantum memory for superconducting circuits. Understanding the dynamics of such ensembles is a necessary step towards achieving this goal. Here, we investigate the dynamics of an ensemble of nitrogen impurities (P1 centers) in diamond using magnetic-field controlled coupling to the first two modes of a superconducting (NbTiN) coplanar waveguide resonator. Three hyperfine-split spin sub-ensembles are clearly resolved in the 0.25-1.2 K temperature range, with a collective coupling strength extrapolating to 23 MHz at full polarization. The coupling to multiple modes allows us to distinguish the contributions of dipolar broadening and magnetic field inhomogeneity to the spin linewidth. We find the spin polarization recovery rate to be temperature independent below 1 K and conclude that spin out-diffusion across the resonator mode volume provides the mechanism for spin relaxation of the ensemble. Furthermore, by pumping spins in one sub-ensemble and probing the spins in the other sub-ensembles, we observe fast steady-state cross-relaxation (compared to spin repolarization) across the hyperfine transitions. These observations have important implications for using the three sub-ensembles as independent quantum memories. Research supported by NWO, FOM, and EU Project SOLID

  3. Spin measurements for 147Sm+n resonances: Further evidence for non-statistical effects

    CERN Document Server

    Köhler, P E; Bredeweg, T A; O`Donnell, J M; Reifarth, R; Rundberg, R S; Vieira, D J; Wouters, J M

    2007-01-01

    We have determined the spins J of resonances in the 147Sm(n,gamma) reaction by measuring multiplicities of gamma-ray cascades following neutron capture. Using this technique, we were able to determine J values for all but 14 of the 140 known resonances below En = 1 keV, including 41 firm J assignments for resonances whose spins previously were either unknown or tentative. These new spin assignments, together with previously determined resonance parameters, allowed us to extract separate level spacings and neutron strength functions for J = 3 and 4 resonances. Furthermore, several statistical test of the data indicate that very few resonances of either spin have been missed below En = 700eV. Because a non-statistical effect recently was reported near En = 350 eV from an analysis of 147Sm(n,alpha) data, we divided the data into two regions; 0 < En < 350 eV and 350 < En < 700 eV. Using neutron widths from a previous measurement and published techniques for correcting for missed resonances and for tes...

  4. Persistent quantum resonance transition in spin Hall transport

    Science.gov (United States)

    Chen, Kuo-Chin; Lee, Hsin-Han; Chang, Ching-Ray

    2016-01-01

    We propose an H-shaped two-dimensional topological insulator (2DTI) as a persistent quantum resonance device. The helical edge states of 2DTI are robust against a nonmagnetic field. However, the helical edge states interfere with bound states created by a nonmagnetic impurity. Transmissions between leads shows two kinds of quantum resonance in this device, the Breit-Wigner resonance and a Fano-like resonance. These resonances can be realized in the device through modulating the on-site impurity potential. Resonances in 2DTI are persistent because the helical state has no backscattering that is protected by time-reversal-symmetry conservation. The finite-size effect in 2DTI leads to the phase transition between the Fano and the Breit-Wigner resonances through modulating the thickness of the 2DTI leads.

  5. Resonant and time-resolved spin noise spectroscopy

    Science.gov (United States)

    Pursley, Brennan C.; Song, X.; Sih, V.

    2015-11-01

    We demonstrate a method to extend the range of pulsed laser spin noise measurements to long spin lifetimes. We use an analog detection scheme with a bandwidth limited only by laser pulse duration. Our model uses statistics and Bloch-Torrey equations to extract the Lande g-factor, Faraday cross-section σ F , and spin lifetime τ s , while accounting for finite detector response. Varying the magnetic field with a fixed probe-probe delay yields τ s when it is longer than the laser repetition period. Varying the probe-probe delay with a fixed field produces a time-domain measurement of the correlation function.

  6. Soft spin dipole giant resonances in 40Ca

    CERN Document Server

    Stuhl, L; Csatlos, M; Marketin, T; Litvinova, E; Adachi, T; Algora, A; Daeven, J; Estevez, E; Fujita, H; Fujita, Y; Guess, C; Gulyas, J; Hatanaka, K; Hirota, K; Ong, H J; Ishikawa, D; Matsubara, H; Meharchand, R; Molina, F; Okamura, H; Perdikakis, G; Rubio, B; Scholl, C; Suzuki, T; Susoy, G; Tamii, A; Thies, J; Zegers, R; Zenihiro, J

    2013-01-01

    High resolution experimental data has been obtained for the 40,42,44,48Ca(3He,t)Sc charge exchange reaction at 420 MeV beam energy, which favors the spin-isospin excitations. The measured angular distributions were analyzed for each state separately, and the relative spin dipole strength has been extracted for the first time. The low-lying spin-dipole strength distribution in 40Sc shows some interesting periodic gross feature. It resembles to a soft, dumped multi-phonon vibrational band with $\\hbar\\omega$= 1.8 MeV, which might be associated to pairing vibrations around $^{40}$Ca.

  7. Spin and charge thermopower of resonant tunneling diodes

    International Nuclear Information System (INIS)

    We investigate thermoelectric effects in quantum well systems. Using the scattering approach for coherent conductors, we calculate the thermocurrent and thermopower both in the spin-degenerate case and in the presence of giant Zeeman splitting due to magnetic interactions in the quantum well. We find that the thermoelectric current at linear response is maximal when the well level is aligned with the Fermi energy and is robust against thermal variations. Furthermore, our results show a spin voltage generation in response to the applied thermal bias, giving rise to large spin Seebeck effects tunable with external magnetic fields, quantum well tailoring, and background temperature

  8. Spin and charge thermopower of resonant tunneling diodes

    Science.gov (United States)

    Nicolau, Javier H.; Sánchez, David

    2014-03-01

    We investigate thermoelectric effects in quantum well systems. Using the scattering approach for coherent conductors, we calculate the thermocurrent and thermopower both in the spin-degenerate case and in the presence of giant Zeeman splitting due to magnetic interactions in the quantum well. We find that the thermoelectric current at linear response is maximal when the well level is aligned with the Fermi energy and is robust against thermal variations. Furthermore, our results show a spin voltage generation in response to the applied thermal bias, giving rise to large spin Seebeck effects tunable with external magnetic fields, quantum well tailoring, and background temperature.

  9. Soft spin-dipole resonances in 40Ca

    International Nuclear Information System (INIS)

    High resolution experimental data has been obtained for the 40,42,44,48Ca(3He,t)Sc charge exchange reaction at 420 MeV beam energy, which favors the spin-isospin excitations. The measured angular distributions were analyzed for each state separately, and the relative spin dipole strength has been extracted for the first time. The low-lying spin-dipole strength distribution in 40Sc shows some interesting periodic gross feature. It resembles to a soft, damped multi-phonon vibrational band with hω= 1.8 MeV, which might be associated to pairing vibrations around 40Ca.

  10. Application of magnetic resonance force microscopy cyclic adiabatic inversion for a single-spin measurement

    CERN Document Server

    Berman, G P; Chapline, G; Gurvitz, S A; Hammel, P C; Pelekhov, D V; Suter, A; Tsifrinovich, V I

    2003-01-01

    We consider the process of a single-spin measurement using magnetic resonance force microscopy (MRFM) with a cyclic adiabatic inversion (CAI). This technique is also important for different applications, including a measurement of a qubit state in quantum computation. The measurement takes place through the interaction of a single spin with a cantilever modelled by a quantum oscillator in a coherent state in a quasi-classical range of parameters. The entire system is treated rigorously within the framework of the Schroedinger equation. For a many-spin system our equations accurately describe conventional MRFM experiments involving CAI of the spin system. Our computer simulations of the quantum spin-cantilever dynamics show that the probability distribution for the cantilever position develops two asymmetric peaks with the total relative probabilities mainly dependent on the initial angle between the directions of the average spin and the effective magnetic field, in the rotating frame. We show that each of th...

  11. Intrinsic oscillations of spin current polarization in a paramagnetic resonant tunneling diode

    Science.gov (United States)

    Wójcik, P.; Adamowski, J.; Wołoszyn, M.; Spisak, B. J.

    2012-10-01

    A spin- and time-dependent electron transport has been studied in a paramagnetic resonant tunneling diode using the self-consistent Wigner-Poisson method. Based on the calculated current-voltage characteristics in an external magnetic field, we have demonstrated that under a constant bias both the spin-up and spin-down current components exhibit the THz oscillations in two different bias voltage regimes. We have shown that the oscillations of the spin-up (down) polarized current result from the coupling between the two resonance states: one localized in the triangular quantum well created in the emitter region and the second localized in the main quantum well. We have also elaborated the one-electron model of the current oscillations, which confirms the results obtained with the Wigner-Poisson method. The spin current oscillations can lower the effectiveness of spin filters based on the paramagnetic resonant tunneling structures and can be used to design the generators of the spin polarized current THz oscillations that can operate under the steady bias and constant magnetic field.

  12. Methodological considerations of electron spin resonance spin trapping techniques for measuring reactive oxygen species generated from metal oxide nanomaterials

    Science.gov (United States)

    Jeong, Min Sook; Yu, Kyeong-Nam; Chung, Hyun Hoon; Park, Soo Jin; Lee, Ah Young; Song, Mi Ryoung; Cho, Myung-Haing; Kim, Jun Sung

    2016-05-01

    Qualitative and quantitative analyses of reactive oxygen species (ROS) generated on the surfaces of nanomaterials are important for understanding their toxicity and toxic mechanisms, which are in turn beneficial for manufacturing more biocompatible nanomaterials in many industrial fields. Electron spin resonance (ESR) is a useful tool for detecting ROS formation. However, using this technique without first considering the physicochemical properties of nanomaterials and proper conditions of the spin trapping agent (such as incubation time) may lead to misinterpretation of the resulting data. In this report, we suggest methodological considerations for ESR as pertains to magnetism, sample preparation and proper incubation time with spin trapping agents. Based on our results, each spin trapping agent should be given the proper incubation time. For nanomaterials having magnetic properties, it is useful to remove these nanomaterials via centrifugation after reacting with spin trapping agents. Sonication for the purpose of sample dispersion and sample light exposure should be controlled during ESR in order to enhance the obtained ROS signal. This report will allow researchers to better design ESR spin trapping applications involving nanomaterials.

  13. Hysteresis loops of spin-dependent electronic current in a paramagnetic resonant tunnelling diode

    International Nuclear Information System (INIS)

    Nonlinear properties of the spin-dependent electronic transport through a semiconductor resonant tunnelling diode with a paramagnetic quantum well are considered. The spin-dependent Wigner–Poisson model of the electronic transport and the two-current Mott’s formula for the independent spin channels are applied to determine the current–voltage curves of the nanodevice. Two types of the electronic current hysteresis loops are found in the current–voltage characteristics for both the spin components of the electronic current. The physical interpretation of these two types of the electronic current hysteresis loops is given based on the analysis of the spin-dependent electron densities and the potential energy profiles. The differences between the current–voltage characteristics for both the spin components of the electronic current allow us to explore the changes of the spin polarization of the current for different electric fields and determine the influence of the electronic current hysteresis on the spin polarization of the current flowing through the paramagnetic resonant tunnelling diode. (paper)

  14. Hysteresis loops of spin-dependent electronic current in a paramagnetic resonant tunnelling diode

    Science.gov (United States)

    Wójcik, P.; Spisak, B. J.; Wołoszyn, M.; Adamowski, J.

    2012-11-01

    Nonlinear properties of the spin-dependent electronic transport through a semiconductor resonant tunnelling diode with a paramagnetic quantum well are considered. The spin-dependent Wigner-Poisson model of the electronic transport and the two-current Mott’s formula for the independent spin channels are applied to determine the current-voltage curves of the nanodevice. Two types of the electronic current hysteresis loops are found in the current-voltage characteristics for both the spin components of the electronic current. The physical interpretation of these two types of the electronic current hysteresis loops is given based on the analysis of the spin-dependent electron densities and the potential energy profiles. The differences between the current-voltage characteristics for both the spin components of the electronic current allow us to explore the changes of the spin polarization of the current for different electric fields and determine the influence of the electronic current hysteresis on the spin polarization of the current flowing through the paramagnetic resonant tunnelling diode.

  15. Parametrization, molecular dynamics simulation and calculation of electron spin resonance spectra of a nitroxide spin label on a poly-alanine alpha helix

    OpenAIRE

    Sezer, Deniz; Freed, Jack H.; Roux, Benoît

    2008-01-01

    The nitroxide spin label 1-oxyl-2,2,5,5-tetramethylpyrroline-3-methyl-methanethiosulfonate (MTSSL), commonly used in site-directed spin labeling of proteins, is studied with molecular dynamics (MD) simulations. After developing force field parameters for the nitroxide moiety and the spin label linker, we simulate MTSSL attached to a poly-alanine alpha helix in explicit solvent to elucidate the factors affecting its conformational dynamics. Electron spin resonance spectra at 9 and 250 GHz are ...

  16. Electron-nuclear double resonance spectroscopy (and electron spin-echo envelope modulation spectroscopy) in bioinorganic chemistry

    OpenAIRE

    Hoffman, Brian M.

    2003-01-01

    This perspective discusses the ways that advanced paramagnetic resonance techniques, namely electron-nuclear double resonance (ENDOR) and electron spin-echo envelope modulation (ESEEM) spectroscopies, can help us understand how metal ions function in biological systems.

  17. Performance test of neutron resonance spin echo at a pulsed source

    International Nuclear Information System (INIS)

    Neutron resonance spin echo (NRSE) spectroscopy enables us to measure neutron quasielastic scattering with high-energy resolution. It is desirable to apply NRSE spectroscopy to pulsed neutron sources because this application allows a very wide range of the spin echo time. We have already developed the neutron resonance spin flipper applicable to a polychromatic pulsed neutron beam, which is necessary for the TOF-NRSE method. Using this flipper, we have succeeded in observing spin echo signals with visibility higher than 0.65 for the pulsed neutron beam with wavelength from 0.3 to 0.9 nm. We discuss the prospect of the NRSE spectrometer with high-energy resolution on the basis of the present result

  18. Interaction of bee venom melittin with zwitterionic and negatively charged phospholipid bilayers : a spin-label electron spin resonance study

    OpenAIRE

    Kleinschmidt, Jörg H.; Mahaney, James E.; Thomas, David D.; Marsh, Derek

    1997-01-01

    Electron spin resonance (ESR) spectroscopy was used to study the penetration and interaction of bee venom melittin with dimyristoylphosphatidylcholine (DMPC) and ditetradecylphosphatidylglycerol (DTPG) bilayer membranes. Melittin is a surface-active, amphipathic peptide and serves as a useful model for a variety of membrane interactions, including those of presequences and signal peptides, as well as the charged subdomain of the cardiac regulatory protein phospholamban. Derivatives of phospha...

  19. Radiation-sterilized bone grafts evaluated by electron spin resonance technique and mechanical tests

    International Nuclear Information System (INIS)

    The activities of the Central Tissue Bank in Poland are reviewed. Emphasis is placed on evaluation of changes in the mechanical properties of bone tissue subjected to lyophilization and radiosterilization and the application of the electron spin resonance technique in the research of mineralizing tissues. The following topics are discussed: technology of tissue conservation; clinical results of conserved tissue application; mechanical properties of preserved bone; free radicals and other paramagnetic substances in radiosterilized bone grafts; electron spin resonance studies of irradiated bone tissue; electron spin resonance analysis of irradiated hydroxyapatites in the course of their synthesis in vitro; stable paramagnetic centers as labels in research on bone graft resorption, creeping substitution, and new bone formation; determination of crystallinity of various mineralized tissues; and dosimetry of the absorbed dose of ionizing radiation

  20. Effect of Electric and Magnetic Fields on Spin Dynamics in the Resonant EDM Experiment

    CERN Document Server

    Silenko, A J

    2006-01-01

    An out-of-plane motion of spin in the resonant EDM experiment (Y.F. Orlov, Proc. of STORI'05, p. 223; Y.K. Semertzidis, ibid., p. 70) is affected by electric and magnetic fields. The effect of a resonant electric field is significant, while the contribution from a magnetic field caused by an oscillating part of particle velocity is dominant. The amplitude of effective field defining the resonant effect has been found. The effect of electric field on the spin dynamics has not been taken into account in previous works. This effect is considerable and leads to decreasing the EDM effect for the deuteron and increasing it for the proton. The spin dynamics has been calculated.

  1. Quantum Computation Based on Magic-Angle-Spinning Solid State Nuclear Magnetic Resonance Spectroscopy

    OpenAIRE

    Ding, Shangwu; McDowell, Charles A.; Ye, Chaohui; Zhan, Mingsheng; Zhu, Xiwen; Gao, Kelin; Sun, Xianping; Mao, Xi-An; Liu, Maili

    2001-01-01

    Magic-angle spinning (MAS) solid state nuclear magnetic resonance (NMR) spectroscopy is shown to be a promising technique for implementing quantum computing. The theory underlying the principles of quantum computing with nuclear spin systems undergoing MAS is formulated in the framework of formalized quantum Floquet theory. The procedures for realizing state labeling, state transformation and coherence selection in Floquet space are given. It suggests that by this method, the largest number o...

  2. Spin-wave resonance in the FeBr2 magnetic thin film

    International Nuclear Information System (INIS)

    The spin-wave resonance in the thin FeBr2 field-induced metamagnet in the paramagnetic phase with the (001) surfaces and at low temperatures is examined theoretically. It is found that the absorption spectrum is strongly affected by modifications of the surface exchange parameters, Also, the conditions for the appearance of various surface and bulk spin-wave features are discussed. (author)

  3. Realistic simulations of single-spin nondemolition measurement by magnetic resonance force microscopy

    International Nuclear Information System (INIS)

    A requirement for many quantum computation schemes is the ability to measure single spins. This paper examines one proposed scheme: magnetic resonance force microscopy (MRFM), including the effects of thermal noise and back action from monitoring. We derive a simplified equation using the adiabatic approximation and produce a stochastic pure state unraveling which is useful for numerical simulations. We also calculate the signal-to-noise ratio for single-spin measurement by MRFM, using a quantum Langevin equation approach

  4. Solid-state nuclear-spin quantum computer based on magnetic resonance force microscopy

    International Nuclear Information System (INIS)

    We propose a nuclear-spin quantum computer based on magnetic resonance force microscopy (MRFM). It is shown that an MRFM single-electron spin measurement provides three essential requirements for quantum computation in solids: (a) preparation of the ground state, (b) one- and two-qubit quantum logic gates, and (c) a measurement of the final state. The proposed quantum computer can operate at temperatures up to 1 K. (c) 2000 The American Physical Society

  5. Single-Spin Measurement and Decoherence in Magnetic Resonance Force Microscopy

    CERN Document Server

    Berman, G P; Goan, H S; Gurvitz, S A; Tsifrinovich, V I

    2003-01-01

    We consider a simple version of a cyclic adiabatic inversion (CAI) technique in magnetic resonance force microscopy (MRFM). We study the problem: What component of the spin is measured in the CAI MRFM? We show that the non-destructive detection of the cantilever vibrations provides a measurement of the spin component along the effective magnetic field. This result is based on numerical simulations of the Hamiltonian dynamics (the Schrodinger equation) and the numerical solution of the master equation.

  6. Solid-State Nuclear Spin Quantum Computer Based on Magnetic Resonance Force Microscopy

    CERN Document Server

    Berman, G P; Hammel, P C; Tsifrinovich, V I

    1999-01-01

    We propose a nuclear spin quantum computer based on magnetic resonance force microscopy (MRFM). It is shown that an MRFM single-electron spin measurement provides three essential requirements for quantum computation in solids: (a) preparation of the ground state, (b) one- and two- qubit quantum logic gates, and (c) a measurement of the final state. The proposed quantum computer can operate at temperatures up to 1K.

  7. Estimation of the Postmortem Duration of Mouse Tissue by Electron Spin Resonance Spectroscopy

    OpenAIRE

    Toshiko Sawaguchi; Hideko Kanazawa; Tomohisa Mori; Shinobu Ito

    2011-01-01

    Electron spin resonance (ESR) method is a simple method for detecting various free radicals simultaneously and directly. However, ESR spin trap method is unsuited to analyze weak ESR signals in organs because of water-induced dielectric loss (WIDL). To minimize WIDL occurring in biotissues and to improve detection sensitivity to free radicals in tissues, ESR cuvette was modified and used with 5,5-dimethtyl-1-pyrroline N-oxide (DMPO). The tissue samples were mouse brain, hart, lung, liver, kid...

  8. Site directed spin labelling and pulsed dipolar electron paramagnetic resonance (double electron-electron resonance) of force activation in muscle

    International Nuclear Information System (INIS)

    The recent development of site specific spin labelling and advances in pulsed electron paramagnetic resonance(EPR) have established spin labelling as a viable structural biology technique. Specific protein sites or whole domains can be selectively targeted for spin labelling by cysteine mutagenesis. The secondary structure of the proteins is determined from the trends in EPR signals of labels attached to consecutive residues. Solvent accessibility or label mobility display periodicities along the labelled polypeptide chain that are characteristic of β-strands (periodicity of 2 residues) or α-helices (3.6 residues). Low-resolution 3D structure of proteins is determined from the distance restraints. Two spin labels placed within 60-70 A of each other create a local dipolar field experienced by the other spin labels. The strength of this field is related to the interspin distance, ∝ r-3. The dipolar field can be measured by the broadening of the EPR lines for the short distances (8-20 A) or for the longer distances (17-70 A) by the pulsed EPR methods, double electron-electron resonance(DEER) and double quantum coherence (DQC). A brief review of the methodology and its applications to the multisubunit muscle protein troponin is presented below

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

    Energy Technology Data Exchange (ETDEWEB)

    Renee Fatemi

    2002-01-01

    Inclusive double spin asymmetries have been measured for {rvec p}({rvec e},e{prime}) using the CLAS detector and a polarized {sup 15}NH{sub 3} target at Jefferson Lab in 1998. The virtual photon asymmetry A{sub 1}, the longitudinal spin structure function, g{sub 1} (x, Q{sup 2}), and the first moment {Gamma}{sub 1}{sup p}, have been extracted for a Q{sup 2} range of 0.15-2.0 GeV{sup 2}. These results provide insight into the low Q{sup 2} evolution of spin dependent asymmetries and structure functions as well as the transition of {Gamma}{sub 1}{sup p} from the photon point, where the Gerasimov, Drell and Hearn Sum Rule is expected to be satisfied, to the deep inelastic region.

  10. Spin measurements for 147Sm+n resonances: Further evidence for nonstatistical effects

    International Nuclear Information System (INIS)

    We have determined the spins J of resonances in the 147Sm(n,γ) reaction by measuring multiplicities of γ-ray cascades following neutron capture. Using this technique, we were able to determine J values for all but 14 of the 141 known resonances below En=1 keV, including 41 firm J assignments for resonances whose spins previously were either unknown or tentative. These new spin assignments, together with previously determined resonance parameters, allowed us to extract level spacings (D0,3=11.76±0.93 and D0,4=11.21±0.85 eV) and neutron strength functions (104S0,3=4.70±0.91 and 104S0,4=4.93±0.92) for J=3 and 4 resonances, respectively. Furthermore, cumulative numbers of resonances and cumulative reduced neutron widths as functions of resonance energy indicate that very few resonances of either spin have been missed below En=700 eV. This conclusion is strengthened by the facts that, over this energy range, Wigner distributions calculated using these D0 values agree with the measured nearest-neighbor level spacings to within the experimental uncertainties, and that the Δ3 values calculated from the data also agree with the expected values. Because a nonstatistical effect recently was reported near En=350 eV from an analysis of 147Sm(n,α) data, we divided the data into two regions; 0nnn0 distribution for resonances below 350 eV is consistent with the expected Porter-Thomas distribution. However, we found that Γn0 data in the 350n2 distribution having ν≥2 We discuss possible explanations for these observed nonstatistical effects and their possible relation to similar effects previously observed in other nuclides

  11. On The $Q^2$ Dependence of The Spin Structure Function In The Resonance Region

    CERN Document Server

    Li, Z; Li, Zhenping; Li, Zhujun

    1994-01-01

    In this paper, we show what we can learn from the CEBAF experiments on spin-structure functions, and the transition from the Drell-Hearn-Gerasimov sum rule in the real photon limit to the spin dependent sum rules in the deep inelastic scattering, and how the asymmetry $A_1(x,Q^2)$ approaches the scaling limit in the resonance region. The spin structure function in the resonance region alone can not determine the spin-dependent sum rule due to the kinematic restriction of the resonance region. The integral $\\int_0^1 \\frac {A_1(x,Q^2)F_2(x,Q^2)}{2x(1+R(x,Q^2))}dx$ is estimated from $Q^2=0$ to $2.5$ GeV$^2$. The result shows that there is a region where both contributions from the baryon resonances and the deep inelastic scattering are important, thus provides important information on the high twist effects on the spin dependent sum rule.

  12. Modified approach to single-spin detection using magnetic resonance force microscopy

    International Nuclear Information System (INIS)

    The magnetic moment of a single spin interacting with a cantilever in magnetic resonance force microscopy (MRFM) experiences quantum jumps in orientation rather than smooth oscillations. These jumps cannot be detected by a conventional MRFM based on observation of driven resonant oscillations of a cantilever. In this paper, we propose a method which should allow detection of the magnetic signal from a single spin using a modification of a conventional MRFM. We estimate the opportunity to detect the magnetic signal from a single proton. (c) 2000 The American Physical Society

  13. Effect of nonlinearity of spin interaction with electromagnetic resonance field on characteristics of polarized nuclear target

    International Nuclear Information System (INIS)

    Interaction of incident nuclear particle beam with J = 1/2 (neutrons) spin and (J = 1/2) protons with the target substance is considered. It is shown that neutron polarization at the target exit and neutron transparency (G) of the target depend significantly on incident wave amplitude level and physical parameter values which characterize the target, such as target temperature, resonator mirror reflection factor, number of spins interacting with the field, etc. Under interaction of neutrons with a target resonator which features a high mirror reflection factor and low losses for absorption which is not related to magnetic dipole absorption, a bistable response of neutron polarization and G manifests itself. 1 ref

  14. High temperature spin dynamics in linear magnetic chains, molecular rings, and segments by nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Adelnia, Fatemeh; Lascialfari, Alessandro [Dipartimento di Fisica, Università degli Studi di Milano and INSTM, Milano (Italy); Dipartimento di Fisica, Università degli Studi di Pavia and INSTM, Pavia (Italy); Mariani, Manuel [Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna (Italy); Ammannato, Luca; Caneschi, Andrea; Rovai, Donella [Dipartimento di Chimica, Università degli Studi di Firenze and INSTM, Firenze (Italy); Winpenny, Richard; Timco, Grigore [School of Chemistry, The University of Manchester, Manchester (United Kingdom); Corti, Maurizio, E-mail: maurizio.corti@unipv.it; Borsa, Ferdinando [Dipartimento di Fisica, Università degli Studi di Pavia and INSTM, Pavia (Italy)

    2015-05-07

    We present the room temperature proton nuclear magnetic resonance (NMR) nuclear spin-lattice relaxation rate (NSLR) results in two 1D spin chains: the Heisenberg antiferromagnetic (AFM) Eu(hfac){sub 3}NITEt and the magnetically frustrated Gd(hfac){sub 3}NITEt. The NSLR as a function of external magnetic field can be interpreted very well in terms of high temperature spin dynamics dominated by a long time persistence of the decay of the two-spin correlation function due to the conservation of the total spin value for isotropic Heisenberg chains. The high temperature spin dynamics are also investigated in Heisenberg AFM molecular rings. In both Cr{sub 8} closed ring and in Cr{sub 7}Cd and Cr{sub 8}Zn open rings, i.e., model systems for a finite spin segment, an enhancement of the low frequency spectral density is found consistent with spin diffusion but the high cut-off frequency due to intermolecular anisotropic interactions prevents a detailed analysis of the spin diffusion regime.

  15. Wave function collapses in a single spin magnetic resonance force microscopy

    International Nuclear Information System (INIS)

    We study the effects of wave function collapses in the oscillating cantilever driven adiabatic reversals (OSCAR) magnetic resonance force microscopy (MRFM) technique. The quantum dynamics of the cantilever tip (CT) and the spin is analyzed and simulated taking into account the magnetic noise on the spin. The deviation of the spin from the direction of the effective magnetic field causes a measurable shift of the frequency of the CT oscillations. We show that the experimental study of this shift can reveal the information about the average time interval between the consecutive collapses of the wave function

  16. Wave function collapses in a single spin magnetic resonance force microscopy

    CERN Document Server

    Berman, G P; Tsifrinovich, V I

    2004-01-01

    We study the effects of wave function collapses in the oscillating cantilever driven adiabatic reversals (OSCAR) magnetic resonance force microscopy (MRFM) technique. The quantum dynamics of the cantilever tip (CT) and the spin is analyzed and simulated taking into account the magnetic noise on the spin. The deviation of the spin from the direction of the effective magnetic field causes a measurable shift of the frequency of the CT oscillations. We show that the experimental study of this shift can reveal the information about the average time interval between the consecutive collapses of the wave function

  17. CONDITIONS OF PASSAGE AND ENTRAPMENT OF TERRESTRIAL PLANETS IN SPIN-ORBIT RESONANCES

    International Nuclear Information System (INIS)

    The dynamical evolution of terrestrial planets resembling Mercury in the vicinity of spin-orbit resonances is investigated using comprehensive harmonic expansions of the tidal torque taking into account the frequency-dependent quality factors and Love numbers. The torque equations are integrated numerically with a small step in time, including the oscillating triaxial torque components but neglecting the layered structure of the planet and assuming a zero obliquity. We find that a Mercury-like planet with a current value of orbital eccentricity (0.2056) is always captured in 3:2 resonance. The probability of capture in the higher 2:1 resonance is approximately 0.23. These results are confirmed by a semi-analytical estimation of capture probabilities as functions of eccentricity for both prograde and retrograde evolutions of spin rate. As follows from analysis of equilibrium torques, entrapment in 3:2 resonance is inevitable at eccentricities between 0.2 and 0.41. Considering the phase space parameters at the times of periastron, the range of spin rates and phase angles for which an immediate resonance passage is triggered is very narrow, and yet a planet like Mercury rarely fails to align itself into this state of unstable equilibrium before it traverses 2:1 resonance.

  18. A new Skyrme energy density functional for a better description of spin-isospin resonances

    Science.gov (United States)

    Roca-Maza, X.; Colò, G.; Cao, Li-Gang; Sagawa, H.

    2015-10-01

    A correct determination of the isospin and spin-isospin properties of the nuclear effective interaction should lead to an accurate description of the Gamow-Teller resonance (GT), the Spin Dipole Resonance (SDR), the Giant Dipole Resonance (GDR) or the Antianalog Giant Dipole Resonance (AGDR), among others. A new Skyrme energy density functional named SAMi is introduced with the aim of going a step forward in setting the bases for a more precise description of spin-isospin resonances [1, 2]. In addition, we will discuss some new features of our analysis on the AGDR in 208Pb [3] as compared with available experimental data on this resonance [4, 5, 6], and on the GDR [7]. Such study, guided by a simple yet physical pocket formula, has been developed by employing the so called SAMi-J family of systematically varied interactions. This set of interactions is compatible with experimental data for values of the symmetry energy at saturation J and slope parameter L falling in the ranges 31-33 MeV and 75-95 MeV, respectively.

  19. A new Skyrme energy density functional for a better description of spin-isospin resonances

    International Nuclear Information System (INIS)

    A correct determination of the isospin and spin-isospin properties of the nuclear effective interaction should lead to an accurate description of the Gamow-Teller resonance (GT), the Spin Dipole Resonance (SDR), the Giant Dipole Resonance (GDR) or the Antianalog Giant Dipole Resonance (AGDR), among others. A new Skyrme energy density functional named SAMi is introduced with the aim of going a step forward in setting the bases for a more precise description of spin-isospin resonances [1, 2]. In addition, we will discuss some new features of our analysis on the AGDR in 208Pb [3] as compared with available experimental data on this resonance [4, 5, 6], and on the GDR [7]. Such study, guided by a simple yet physical pocket formula, has been developed by employing the so called SAMi-J family of systematically varied interactions. This set of interactions is compatible with experimental data for values of the symmetry energy at saturation J and slope parameter L falling in the ranges 31−33 MeV and 75−95 MeV, respectively

  20. A new Skyrme energy density functional for a better description of spin-isospin resonances

    Energy Technology Data Exchange (ETDEWEB)

    Roca-Maza, X., E-mail: xavier.roca.maza@mi.infn.it [Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sez. di Milano, via Celoria 16, 20133 Milano (Italy); Colò, G. [Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sez. di Milano, via Celoria 16, 20133 Milano (Italy); Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); Cao, Li-Gang [Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); School of Mathematics and Physics, North China Electric Power University, Beijing 102206 (China); State Key Laboratory of Theoretical Physics, ITP, Chinese Academy of Sciences, Beijing 100190 (China); National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000 (China); Sagawa, H. [Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); Center for Mathematics and Physics, University of Aizu, Aizu-Wakamatsu, Fukushima 965-8580 (Japan); RIKEN, Nishina Center, Wako, 351-0198 (Japan)

    2015-10-15

    A correct determination of the isospin and spin-isospin properties of the nuclear effective interaction should lead to an accurate description of the Gamow-Teller resonance (GT), the Spin Dipole Resonance (SDR), the Giant Dipole Resonance (GDR) or the Antianalog Giant Dipole Resonance (AGDR), among others. A new Skyrme energy density functional named SAMi is introduced with the aim of going a step forward in setting the bases for a more precise description of spin-isospin resonances [1, 2]. In addition, we will discuss some new features of our analysis on the AGDR in {sup 208}Pb [3] as compared with available experimental data on this resonance [4, 5, 6], and on the GDR [7]. Such study, guided by a simple yet physical pocket formula, has been developed by employing the so called SAMi-J family of systematically varied interactions. This set of interactions is compatible with experimental data for values of the symmetry energy at saturation J and slope parameter L falling in the ranges 31−33 MeV and 75−95 MeV, respectively.

  1. Unraveling multi-spin effects in rotational resonance nuclear magnetic resonance using effective reduced density matrix theory

    International Nuclear Information System (INIS)

    A quantum-mechanical model integrating the concepts of reduced density matrix and effective Hamiltonians is proposed to explain the multi-spin effects observed in rotational resonance (R2) nuclear magnetic resonance (NMR) experiments. Employing this approach, the spin system of interest is described in a reduced subspace inclusive of its coupling to the surroundings. Through suitable model systems, the utility of our theory is demonstrated and verified with simulations emerging from both analytic and numerical methods. The analytic results presented in this article provide an accurate description/interpretation of R2 experimental results and could serve as a test-bed for distinguishing coherent/incoherent effects in solid-state NMR

  2. Ferromagnetic resonance dispersion relation of spin valve systems

    Science.gov (United States)

    Rodríguez-Suárez, R. L.; Rezende, S. M.; Azevedo, A.

    2005-08-01

    We derive the FMR dispersion relation of spin valve systems taking into account the competition that can appears between the direct exchange bias coupling and the indirect interlayer coupling. For uncoupled ferromagnetic (FM) layers, the system exhibits a dispersion relation corresponding to two independent systems: a single FM layer (free layer) and an exchange-coupled bilayer (reference/antiferromagnetic layers). In the interlayer coupled regime a unidirectional anisotropy is induced in the free layer and the FMR field is overall downshifted.

  3. Magnetic defects in chemically converted graphene nanoribbons: electron spin resonance investigation

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao Singamaneni

    2014-04-01

    Full Text Available Electronic spin transport properties of graphene nanoribbons (GNRs are influenced by the presence of adatoms, adsorbates and edge functionalization. To improve the understanding of the factors that influence the spin properties of GNRs, local (element spin-sensitive techniques such as electron spin resonance (ESR spectroscopy are important for spintronics applications. Here, we present results of multi-frequency continuous wave (CW, pulse and hyperfine sublevel correlation (HYSCORE ESR spectroscopy measurements performed on oxidatively unzipped graphene nanoribbons (GNRs, which were subsequently chemically converted (CCGNRs with hydrazine. ESR spectra at 336 GHz reveal an isotropic ESR signal from the CCGNRs, of which the temperature dependence of its line width indicates the presence of localized unpaired electronic states. Upon functionalization of CCGNRs with 4-nitrobenzene diazonium tetrafluoroborate, the ESR signal is found to be 2 times narrower than that of pristine ribbons. NH3 adsorption/desorption on CCGNRs is shown to narrow the signal, while retaining the signal intensity and g value. The electron spin-spin relaxation process at 10 K is found to be characterized by slow (163 ns and fast (39 ns components. HYSCORE ESR data demonstrate the explicit presence of protons and 13C atoms. With the provided identification of intrinsic point magnetic defects such as proton and 13C has been reported, which are roadblocks to spin travel in graphene-based materials, this work could help in advancing the present fundamental understanding on the edge-spin (or magnetic-based transport properties of CCGNRs.

  4. Experimental and theoretical study of conduction electron spin resonance in aluminum

    International Nuclear Information System (INIS)

    The purpose of the present work is to contribute to the elucidation of the spin resonance properties of conduction electron in pure metals. We follow three complementary ways: 1) We compare between them all metals where spin resonance has been observed. We show the influence of spin-orbit and of the metal valence, and we deduce the likely importance of the Fermi surface complexity, in particular concerning the g factor. 2) We have assembled an original EPR spectrometer, working at 350 MHz. This 'low' frequency enables to minimize the line broadenings due to g factor distributions over the Fermi surface. Nevertheless we were unable to detect any new resonance. This apparatus performed some experiments on aluminum, an exemplary metal: spin relaxation on dislocations and surfaces; study of g between 50 and 110 K. 3) We calculate the g factor at every point of the Fermi surface of aluminum, by introducing the spin-orbit potential as a perturbation. An important difficulty remains, linked to the choice of the wave function phase. Moreover we propose a phenomenological model based on the narrowing of the so calculated g distribution by two types of motion: a random one corresponding to diffusion of electrons on the crystalline imperfections, and a coherent one around the cyclotron orbits. A qualitative model accounts relatively well for the experimental facts

  5. Current-induced spin torque resonance of magnetic insulators affected by field-like spin-orbit torques and out-of-plane magnetizations

    International Nuclear Information System (INIS)

    The spin-torque ferromagnetic resonance (ST-FMR) in a bilayer system consisting of a magnetic insulator such as Y3Fe5O12 and a normal metal with spin-orbit interaction such as Pt is addressed theoretically. We model the ST-FMR for all magnetization directions and in the presence of field-like spin-orbit torques based on the drift-diffusion spin model and quantum mechanical boundary conditions. ST-FMR experiments may expose crucial information about the spin-orbit coupling between currents and magnetization in the bilayers

  6. Photoelectric detection of electron spin resonance of nitrogen-vacancy centres in diamond

    Science.gov (United States)

    Bourgeois, E.; Jarmola, A.; Siyushev, P.; Gulka, M.; Hruby, J.; Jelezko, F.; Budker, D.; Nesladek, M.

    2015-01-01

    The readout of negatively charged nitrogen-vacancy centre electron spins is essential for applications in quantum computation, metrology and sensing. Conventional readout protocols are based on the detection of photons emitted from nitrogen-vacancy centres, a process limited by the efficiency of photon collection. We report on an alternative principle for detecting the magnetic resonance of nitrogen-vacancy centres, allowing the direct photoelectric readout of nitrogen-vacancy centres spin state in an all-diamond device. The photocurrent detection of magnetic resonance scheme is based on the detection of charge carriers promoted to the conduction band of diamond by two-photon ionization of nitrogen-vacancy centres. The optical and photoelectric detection of magnetic resonance are compared, by performing both types of measurements simultaneously. The minima detected in the measured photocurrent at resonant microwave frequencies are attributed to the spin-dependent ionization dynamics of nitrogen-vacancy, originating from spin-selective non-radiative transitions to the metastable singlet state. PMID:26486014

  7. Phosphorus-doped thin silica films characterized by magic-angle spinning nuclear magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Jacobsen, H.J.; Skibsted, J.; Kristensen, Martin;

    2001-01-01

    Magic-angle spinning nuclear magnetic resonance spectra of 31P and 29Si have been achieved for a thin silica film doped with only 1.8% 31P and deposited by plasma enhanced chemical vapor deposition on a pure silicon wafer. The observation of a symmetric 31P chemical shift tensor is consistent...

  8. A point of view about identification of irradiated foods by electron spin resonance

    International Nuclear Information System (INIS)

    Principles and conditions required for using electron spin resonance (ESR) in identifying irradiated foods are first put forth. After a literature review, examples of irradiated cereals and French prunes are described in order to derive general conclusions concerning the future of ESR in this field

  9. Double Barrier Resonant Tunneling in Spin-Orbit Coupled Bose—Einstein Condensates

    International Nuclear Information System (INIS)

    We study the double barrier tunneling properties of Dirac particles in spin-orbit coupled Bose—Einstein Condensates. The analytic expression of the transmission coefficient of Dirac particles penetrating into a double barrier is obtained. An interesting resonance tunneling phenomenon is discovered in the Klein block region which has been ignored before

  10. Electron spin resonance in neutron-irradiated graphite. Dependence on temperature and effect of annealing

    International Nuclear Information System (INIS)

    The temperature dependence of the electron spin resonance signal from neutron irradiated graphite has been studied. The results lead to an interpretation of the nature of the paramagnetic centers created by irradiation. In annealing experiments on graphite samples, which had been irradiated at low temperature, two annealing peaks and one anti-annealing peak were found. Interpretations are proposed for these peaks. (author)

  11. Realistic simulations of single-spin nondemolition measurement by magnetic resonance force microscopy

    CERN Document Server

    Brun, T A; Brun, Todd A.; Goan, Hsi-Sheng

    2003-01-01

    A requirement for many quantum computation schemes is the ability to measure single spins. This paper examines one proposed scheme: magnetic resonance force microscopy, including the effects of thermal noise and back-action from monitoring. We derive a simplified equation using the adiabatic approximation, and produce a stochastic pure state unraveling which is useful for numerical simulations.

  12. Resonance induced spin-selective transport behavior in carbon nanoribbon/nanotube/nanoribbon heterojunctions

    International Nuclear Information System (INIS)

    Carbon nanotubes (CNTs) and graphene nanoribbons (GNRs) are attractive in spintronics. Here, we propose GNR/CNT/GNR heterojunctions constructed by attaching zigzag-GNRs at the side-wall of CNT for spintronic devices. The thermal stability and electronic transport properties were explored using ab initio molecular dynamics simulations and nonequilibrium Green's function methods, respectively. Results demonstrate that the sp3-hybridized contacts formed at the interface assure a good thermal stability of the system and make the CNT to be regarded as resonator. Only the electron of one spin-orientation and resonant energy is allowed to transport, resulting in the remarkable spin-selective transport behavior at the ferromagnetic state. - Highlights: • The new mechanism for spin-selective transport in molecular junction is proposed. • The two sp3 contacts formed between CNT and GNR can be regarded as electronic isolators. • The two isolators make the CNT act as a resonator. • Only the electron of one spin-orientation and resonant energy can form standing wave and transport through the whole junction

  13. Resonance induced spin-selective transport behavior in carbon nanoribbon/nanotube/nanoribbon heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiang-Hua [School of Physics and Microelectronics Science, Hunan University, Changsha 410082 (China); Department of Electrical and Information Engineering, Hunan Institute of Engineering, Xiangtan 411101 (China); Wang, Ling-Ling, E-mail: llwang@hnu.edu.cn [School of Physics and Microelectronics Science, Hunan University, Changsha 410082 (China); Li, Xiao-Fei, E-mail: xf.li@uestc.edu.cn [School of Physics and Microelectronics Science, Hunan University, Changsha 410082 (China); School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Chen, Tong; Li, Quan [School of Physics and Microelectronics Science, Hunan University, Changsha 410082 (China)

    2015-09-04

    Carbon nanotubes (CNTs) and graphene nanoribbons (GNRs) are attractive in spintronics. Here, we propose GNR/CNT/GNR heterojunctions constructed by attaching zigzag-GNRs at the side-wall of CNT for spintronic devices. The thermal stability and electronic transport properties were explored using ab initio molecular dynamics simulations and nonequilibrium Green's function methods, respectively. Results demonstrate that the sp{sup 3}-hybridized contacts formed at the interface assure a good thermal stability of the system and make the CNT to be regarded as resonator. Only the electron of one spin-orientation and resonant energy is allowed to transport, resulting in the remarkable spin-selective transport behavior at the ferromagnetic state. - Highlights: • The new mechanism for spin-selective transport in molecular junction is proposed. • The two sp{sup 3} contacts formed between CNT and GNR can be regarded as electronic isolators. • The two isolators make the CNT act as a resonator. • Only the electron of one spin-orientation and resonant energy can form standing wave and transport through the whole junction.

  14. On the spin and parity of a single-produced resonance at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Bolognesi, Sara; Gao, Yanyan; Gritsan, Andrei V.; Melnikov, Kirill; Schulze, Markus; Tran, Nhan V.; Whitbeck, Andrew

    2012-11-01

    The experimental determination of the properties of the newly discovered boson at the Large Hadron Collider is currently the most crucial task in high energy physics. We show how information about the spin, parity, and, more generally, the tensor structure of the boson couplings can be obtained by studying angular and mass distributions of events in which the resonance decays to pairs of gauge bosons, $ZZ, WW$, and $\\gamma \\gamma$. A complete Monte Carlo simulation of the process $pp \\to X \\to VV \\to 4f$ is performed and verified by comparing it to an analytic calculation of the decay amplitudes $X \\to VV \\to 4f$. Our studies account for all spin correlations and include general couplings of a spin $J=0,1,2$ resonance to Standard Model particles. We also discuss how to use angular and mass distributions of the resonance decay products for optimal background rejection. It is shown that by the end of the 8 TeV run of the LHC, it might be possible to separate extreme hypotheses of the spin and parity of the new boson with a confidence level of 99% or better for a wide range of models. We briefly discuss the feasibility of testing scenarios where the resonances is not a parity eigenstate.

  15. High precision beam momentum determination in a synchrotron using a spin resonance method

    CERN Document Server

    Goslawski, P; Gebel, R; Hartmann, M; Kacharava, A; Lehrach, A; Lorentz, B; Maier, R; Mielke, M; Papenbrock, M; Prasuhn, D; Stassen, R; Stein, H J; Stockhorst, H; Ströher, H; Wilkin, C

    2009-01-01

    In order to measure the mass of the eta meson with high accuracy using the d+p -> 3He+eta reaction, the momentum of the circulating deuteron beam in the Cooler Synchrotron COSY of the Forschungszentrum Juelich has to be determined with unprecedented precision. This has been achieved by studying the spin dynamics of the polarized deuteron beam. By depolarizing the beam through the use of an artificially induced spin resonance, it was possible to evaluate its momentum p with a precision of dp/p < 10-4 for a momentum of roughly 3 GeV/c. Different possible sources of error in the application of the spin resonance method are discussed in detail and its possible use during a standard experiment is considered.

  16. Electron spin resonance observation of dehydration-induced spin excitations in quasi-one-dimensional iodo-bridged diplatinum complexes

    Science.gov (United States)

    Tanaka, Hisaaki; Kuroda, Shin-Ichi; Iguchi, Hiroaki; Takaishi, Shinya; Yamashita, Masahiro

    2012-02-01

    Electron spin resonance (ESR) measurements have been performed on a series of quasi-one-dimensional iodo-bridged diplatinum complexes K2[C3H5R(NH3)2][Pt2(pop)4I]·4H2O (pop = P2H2O52-; R = H, CH3, or Cl), where dehydration/rehydration of the crystalline water switches the electronic state reversibly with retention of single crystallinity. We have observed a nonmagnetic nature in as-grown samples, whereas in the dehydrated samples, a clear enhancement of the spin susceptibility has been observed above ˜80 K with the activation energy ranging 50-60 meV. The activated spins originate from isolated Pt3+ state on the chain, as confirmed from the principal g values. Concomitantly, the ESR linewidth exhibits a prominent motional narrowing, suggesting that the activated Pt3+ spins are mobile solitons generated in the doubly degenerate charge-density-wave states of the dehydrated salts.

  17. Epitaxial MnAs Films Studied by Ferromagnetic and Spin Wave Resonance

    Science.gov (United States)

    Toliński, T.; Lenz, K.; Lindner, J.; Baberschke, K.; Ney, A.; Hesjedal, T.; Pampuch, C.; Däweritz, L.; Koch, R.; Ploog, K. H.

    We investigated the anisotropy and intrinsic exchange interaction within MnAs films using ferromagnetic resonance (FMR) and spin wave resonance (SWR), respectively. Apart from the dominating in-plane easy axis a presence of an independent contribution (independent FMR mode) characterized by an out-of-plane easy axis is found in agreement with our previous magnetometric studies. The temperature sweep of the resonance spectra shows a jump both for the resonance field and the resonance linewidth at a temperature of 10°C, i.e., at the transition from the hexagonal (ferromagnetic) α-phase to the region of the coexisting α- and orthorhombic (paramagnetic) β-phase. In the coexistence region the main easy axis lies in-plane and perpendicular to the stripe direction being the direction of the c axis. In the SWR measurements with magnetic field applied close to the normal of the film a set of lines resulting from the excitation of spin waves is observed. The extracted exchange constant is as small as A = 17.7 ×10-10 erg/cm. Moreover, the temperature dependence of the spin wave stiffness constant D = 2A/M has been determined within the coexistence region.

  18. Electron-atom scattering resonances: Complex-scaled multiconfigurational spin-tensor electron propagator method for B-shape resonances

    Science.gov (United States)

    Tsednee, Tsogbayar; Yeager, Danny L.

    2015-06-01

    We develop the complex-scaled multiconfigurational spin-tensor electron propagator (CMCSTEP) technique for the theoretical determination of resonance parameters with electron-atom-molecule systems including open-shell and highly correlated (nondynamical correlation) atoms and molecules. The multiconfigurational spin-tensor electron propagator method developed and implemented by Yeager and his coworkers in real space gives very accurate and reliable ionization potentials and electron affinities. The CMCSTEP method uses a complex-scaled multiconfigurational self-consistent field state as an initial state along with a dilated Hamiltonian where all of the electronic coordinates are scaled by a complex factor. We apply the CMCSTEP and the related M1 methods to get the B-shape resonance parameters using 14 s 11 p and 14 s 11 p 5 d basis sets with 1 s 2 s 2 p 3 s , 1 s 2 s 2 p 3 s 3 p , 1 s 2 s 2 p 3 d , 2 s 2 p 3 s 3 p , 2 s 2 p 3 d , and 2 s 2 p 3 s 3 p 3 d complete active spaces. The CMCSTEP and M1 resonance positions and widths are obtained for the 1 s22 s22 p21D , 1 s22 s 2 p33D , and 1 s 2 s22 p33D , 3S , and 3P shape resonances.

  19. Analog of Electromagnetically Induced Transparency Effect for Two Nano/Micro-mechanical Resonators Coupled With Spin Ensemble

    OpenAIRE

    Chang, Yue; Sun, C. P.

    2011-01-01

    We study a hybrid nano-mechanical system coupled to a spin ensemble as a quantum simulator to favor a quantum interference effect, the electromagnetically induced transparency (EIT). This system consists of two nano-mechanical resonators (NAMRs), each of which coupled to a nuclear spin ensemble. It could be regarded as a crucial element in the quantum network of NAMR arrays coupled to spin ensembles. Here, the nuclear spin ensembles behave as a long-lived transducer to store and transfer the ...

  20. Resonant mixing of optical orbital and spin angular momentum by using chiral silicon nanosphere clusters.

    Science.gov (United States)

    Al-Jarro, Ahmed; Biris, Claudiu G; Panoiu, Nicolae C

    2016-04-01

    We present an in-depth analysis of the resonant intermixing between optical orbital and spin angular momentum of Laguerre-Gaussian (LG) beams, mediated by chiral clusters made of silicon nanospheres. In particular, we establish a relationship between the spin and orbital quantum numbers characterizing the LG beam and the order q of the rotation symmetry group q of the cluster of nanospheres for which resonantly enhanced coupling between the two components of the optical angular momentum is observed. Thus, similar to the case of diffraction grating-mediated transfer of linear momentum between optical beams, we demonstrate that clusters of nanospheres that are invariant to specific rotation transformations can efficiently transfer optical angular momentum between LG beams with different quantum numbers. We also discuss the conditions in which the resonant interaction between LG beams and a chiral cluster of nanospheres leads to the generation of superchiral light. PMID:27136989

  1. One-loop effects from spin-1 resonances in Composite Higgs models

    CERN Document Server

    Contino, Roberto

    2015-01-01

    We compute the 1-loop correction to the electroweak observables from spin-1 resonances in SO(5)/SO(4) composite Higgs models. The strong dynamics is modeled with an effective description comprising the Nambu-Goldstone bosons and the lowest-lying spin-1 resonances. A classification is performed of the relevant operators including custodially-breaking effects from the gauging of hypercharge. The 1-loop contribution of the resonances is extracted in a diagrammatic approach by matching to the low-energy theory of Nambu-Goldstone bosons. We find that the correction is numerically important in a significant fraction of the parameter space and tends to weaken the bounds providing a negative shift to the S parameter.

  2. Resonance-inclined optical nuclear spin polarization of liquids in diamond structures

    CERN Document Server

    Chen, Qiong; Jelezko, Fedor; Retzker, Alex; Plenio, Martin B

    2015-01-01

    Dynamic nuclear polarization (DNP) of molecules in a solution at room temperature has potential to revolutionize nuclear magnetic resonance spectroscopy and imaging. The prevalent methods for achieving DNP in solutions are typically most effective in the regime of small interaction correlation times between the electron and nuclear spins, limiting the size of accessible molecules. To solve this limitation, we design a mechanism for DNP in the liquid phase that is applicable for large interaction correlation times. Importantly, while this mechanism makes use of a resonance condition similar to solid-state DNP, the polarization transfer is robust to a relatively large detuning from the resonance due to molecular motion. We combine this scheme with optically polarized nitrogen vacancy (NV) center spins in nanodiamonds to design a setup that employs optical pumping and is therefore not limited by room temperature electron thermal polarisation. We illustrate numerically the effectiveness of the model in a flow cel...

  3. Thermal mixing in multiple-pulse nuclear quadrupole resonance spin-locking

    International Nuclear Information System (INIS)

    We report on an experimental and theoretical nuclear quadrupole resonance (NQR) multiple-pulse spin-locking study of the thermal mixing process in solids containing nuclei of two different sorts, I>1/2 and S = 1/2, coupled by dipole-dipole interactions and influenced by an external magnetic field. Two coupled equations for the inverse spin temperatures of both the spin systems describing the mutual spin-lattice relaxation and the thermal mixing were obtained using the method of the nonequilibrium state operator. It is shown that the relaxation process is realized with non-exponential time dependence described by a sum of two exponents. The calculated relaxation time versus the multiple-pulse field parameters agrees well with the obtained experimental data in 1,4-dichloro-2-nitrobenzene. The calculated magnetization relaxation time versus the strength of the applied magnetic field agrees well with the obtained experimental data

  4. Signal-background interference for a singlet spin-0 digluon resonance at the LHC

    CERN Document Server

    Martin, Stephen P

    2016-01-01

    Dijet mass distributions can be used to search for spin-0 resonances that couple to two gluons. I show that there is a substantial impact on such searches from the interference between the resonant signal and the continuum QCD background amplitudes. The signal dijet mass distribution is qualitatively modified by this interference, compared to the naive expectation from considering only the pure resonant contribution, even if the total width of the resonance is minimal and very small compared to the experimental dijet mass resolution. The impact becomes more drastic as the total width of the resonance increases. These considerations are illustrated using examples relevant to the 750 GeV diphoton excess recently observed at the LHC.

  5. Analysis of the transient response of nuclear spins in GaAs with/without nuclear magnetic resonance

    Science.gov (United States)

    Rasly, Mahmoud; Lin, Zhichao; Yamamoto, Masafumi; Uemura, Tetsuya

    2016-05-01

    As an alternative to studying the steady-state responses of nuclear spins in solid state systems, working within a transient-state framework can reveal interesting phenomena. The response of nuclear spins in GaAs to a changing magnetic field was analyzed based on the time evolution of nuclear spin temperature. Simulation results well reproduced our experimental results for the transient oblique Hanle signals observed in an all-electrical spin injection device. The analysis showed that the so called dynamic nuclear polarization can be treated as a cooling tool for the nuclear spins: It works as a provider to exchange spin angular momentum between polarized electron spins and nuclear spins through the hyperfine interaction, leading to an increase in the nuclear polarization. In addition, a time-delay of the nuclear spin temperature with a fast sweep of the external magnetic field produces a possible transient state for the nuclear spin polarization. On the other hand, the nuclear magnetic resonance acts as a heating tool for a nuclear spin system. This causes the nuclear spin temperature to jump to infinity: i.e., the average nuclear spins along with the nuclear field vanish at resonant fields of 75As, 69Ga and 71Ga, showing an interesting step-dip structure in the oblique Hanle signals. These analyses provide a quantitative understanding of nuclear spin dynamics in semiconductors for application in future computation processing.

  6. Isotope effect on the spin resonance of boron in silicon

    International Nuclear Information System (INIS)

    The fourfold degeneracy of the boron acceptor ground state in silicon, which is easily lifted by any symmetry breaking perturbation, allows for a strong inhomogeneous broadening of the B-related electron paramagnetic resonance (EPR) lines, e.g. by randomly distributed, defect-induced local strain. In previous studies a number of fundamental questions concerning the line shape, the magnitude of the residual broadening, and the substructure of the B resonances have remained unsolved. We show that local fluctuations of the valence band edge due to the presence of different Si isotopes in the vicinity of the B acceptors can quantitatively account for all inhomogeneous broadening effects in high purity Si with a natural isotope composition. A comparison of our calculations with previous work investigating the B acceptor ground state in the absence of an external magnetic field, provides an independent verification of the energy offsets between the valence bands of 28Si, 29Si, and 30Si. Moreover, our calculations show that the isotopic perturbation also leads to a shift in the g-value of different B-related resonance lines, which could be verified in our experiments.

  7. Application of magnetic resonance force microscopy cyclic adiabatic inversion for a single-spin measurement

    International Nuclear Information System (INIS)

    We consider the process of a single-spin measurement using magnetic resonance force microscopy (MRFM) with a cyclic adiabatic inversion (CAI). This technique is also important for different applications, including a measurement of a qubit state in quantum computation. The measurement takes place through the interaction of a single spin with a cantilever modelled by a quantum oscillator in a coherent state in a quasi-classical range of parameters. The entire system is treated rigorously within the framework of the Schroedinger equation. For a many-spin system our equations accurately describe conventional MRFM experiments involving CAI of the spin system. Our computer simulations of the quantum spin-cantilever dynamics show that the probability distribution for the cantilever position develops two asymmetric peaks with the total relative probabilities mainly dependent on the initial angle between the directions of the average spin and the effective magnetic field, in the rotating frame. We show that each of the peaks is correlated with the direction of the average spin (being along or opposite to the direction of the effective magnetic field). This generates two possible outcomes of a single-spin measurement, similar to the Stern-Gerlach effect. We demonstrate that the generation of the second peak can be significantly suppressed by turning on adiabatically the amplitude of the rf magnetic field. We also show that MRFM CAI can be used both for detecting a signal from a single spin, and for measuring the single-spin state by measuring the phase of the cantilever driving oscillations

  8. Field-assisted electron transport through a symmetric double-well structure with spin-orbit coupling and the Fano-resonance induced spin filtering

    Institute of Scientific and Technical Information of China (English)

    Zhang Cun-Xi; Nie Yi-Hang; Liang Jiu-Qing

    2008-01-01

    We have investigated theoretically the field-driven electron-transport through a double-quantum-well semiconductor-heterostructure with spin-orbit coupling. The numerical results demonstrate that the transmission spectra are divided into two sets due to the bound-state level-splitting and each set contains two asymmetric resonance peaks which may be selectively suppressed by changing the difference in phase between two driving fields. When the phase difference changes from O to π, the dip of asymmetric resonance shifts from one side of resonance peak to the other side and the asymmetric Fano resonance degenerates into the symmetric Breit-Wigner resonance at a critical value of phase difference. Within a given range of incident electron energy, the spin polarization of transmission current is completely governed by the phase difference which may be used to realize the tunable spin filtering.

  9. Nuclear magnetic resonance spin-spin relaxation of the crystals of bone, dental enamel, and synthetic hydroxyapatites.

    Science.gov (United States)

    Wu, Yaotang; Ackerman, Jerome L; Kim, Hyun-Man; Rey, Christian; Barroug, Allal; Glimcher, Melvin J

    2002-03-01

    Studies of the apatitic crystals of bone and enamel by a variety of spectroscopic techniques have established clearly that their chemical composition, short-range order, and physical chemical reactivity are distinctly different from those of pure hydroxyapatite. Moreover, these characteristics change with aging and maturation of the bone and enamel crystals. Phosphorus-31 solid state nuclear magnetic resonance (NMR) spin-spin relaxation studies were carried out on bovine bone and dental enamel crystals of different ages and the data were compared with those obtained from pure and carbonated hydroxyapatites. By measuring the 31P Hahn spin echo amplitude as a function of echo time, Van Vleck second moments (expansion coefficients describing the homonuclear dipolar line shape) were obtained and analyzed in terms of the number density of phosphorus nuclei. 31P magnetization prepared by a 90 degree pulse or by proton-phosphorus cross-polarization (CP) yielded different second moments and experienced different degrees of proton spin-spin coupling, suggesting that these two preparation methods sample different regions, possibly the interior and the surface, respectively, of bone mineral crystals. Distinct differences were found between the biological apatites and the synthetic hydroxyapatites and as a function of the age and maturity of the biological apatites. The data provide evidence that a significant fraction of the protonated phosphates (HPO4(-2)) are located on the surfaces of the biological crystals, and the concentration of unprotonated phosphates (PO4(-3)) within the apatitic lattice is elevated with respect to the surface. The total concentration of the surface HPO4(-2) groups is higher in the younger, less mature biological crystals. PMID:11874238

  10. Electron spin resonance of radicals and metal complexes

    International Nuclear Information System (INIS)

    The materials are a collection of extended synopsis of papers presented at the conference sessions. The broad area of magnetic techniques applications has been described as well as their spectra interpretation methods. The ESR, NMR, ENDOR and spin echo were applied for studying the radiation and UV induced radicals in chemical and biological systems. Also in the study of complexes of metallic ions (having the paramagnetic properties) and their interaction with the matrix, the magnetic techniques has been commonly used. They are also very convenient tool for the study of reaction kinetics and mechanism as well as interaction of paramagnetic species with themselves and crystal lattice or with the surface as for thee catalytic processes

  11. Electron spin resonance of copper labelled myoglobin crystals

    International Nuclear Information System (INIS)

    Single crystals of sperm whale met mioglobin were doped with Cu2+ by immersion in a satured solution of NH3(SO4) containing diluted Cu(SO4). Angular variations of the EPR espectra were measured in the planes: ab, ac* and bc* (c* is an axis perpendicular to the ab plane of the monoclinic crystal). A fitting using a spin Hamiltonian with axial symmetry calculated up to second order gives the EPR hyperfine constants g = (2.328+-0.002), g = (2.069+-0.002), A = (162+-3) gauss and A = (20+-3) gauss. The parallel axis makes an angle of (390 +- 20) with the crystaline b axis. A super hyperfine spectra was evidenciated in a perpendicular direction associated with gxx or gyy. This splitting may be attributed to a spread of a wavefunction of the unpaired electron over one nitrogene of the imidazole ring of the Histidine A10 in Mb: Cu2+

  12. Distinguishing black-hole spin-orbit resonances by their gravitational wave signatures. II: Full parameter estimation

    CERN Document Server

    Trifirò, Daniele; Gerosa, Davide; Berti, Emanuele; Kesden, Michael; Littenberg, Tyson; Sperhake, Ulrich

    2015-01-01

    Gravitational waves from coalescing binary black holes encode the evolution of their spins prior to merger. In the post-Newtonian regime and on the precession timescale, this evolution has one of three morphologies, with the spins either librating around one of two fixed points ("resonances") or circulating freely. In this work we perform full parameter estimation on resonant binaries with fixed masses and spin magnitudes, changing three parameters: a conserved "projected effective spin" $\\xi$ and resonant family $\\Delta\\Phi=0,\\pi$ (which uniquely label the source); the inclination $\\theta_{JN}$ of the binary's total angular momentum with respect to the line of sight (which determines the strength of precessional effects in the waveform); and the signal amplitude. We demonstrate that resonances can be distinguished for a wide range of binaries, except for highly symmetric configurations where precessional effects are suppressed. Motivated by new insight into double-spin evolution, we introduce new variables t...

  13. Spin Vortex Resonance in Non-planar Ferromagnetic Dots

    Science.gov (United States)

    Ding, Junjia; Lapa, Pavel; Jain, Shikha; Khaire, Trupti; Lendinez, Sergi; Zhang, Wei; Jungfleisch, Matthias B.; Posada, Christian M.; Yefremenko, Volodymyr G.; Pearson, John E.; Hoffmann, Axel; Novosad, Valentine

    2016-05-01

    In planar structures, the vortex resonance frequency changes little as a function of an in-plane magnetic field as long as the vortex state persists. Altering the topography of the element leads to a vastly different dynamic response that arises due to the local vortex core confinement effect. In this work, we studied the magnetic excitations in non-planar ferromagnetic dots using a broadband microwave spectroscopy technique. Two distinct regimes of vortex gyration were detected depending on the vortex core position. The experimental results are in qualitative agreement with micromagnetic simulations.

  14. On Mercury's entrapment into the 3:2 spin-orbit resonance

    Science.gov (United States)

    Noyelles, Benoit; Frouard, J.; Makarov, V.; Efroimsky, M.

    2013-10-01

    The rotational dynamics of Mercury is a peculiar case in the Solar System, since it is a supersynchronous, 3:2 resonant state, with the spin period being 2/3 of the orbital one. While it is widely accepted that the significant eccentricity (0.206) favours this configuration, the history of Mercury's despinning remains nonetheless a matter of discussion. At least three scenarios can be found in the scientific literature. The first one considers a homogeneous Mercury that was trapped after several crossings of the resonance, these crossings made possible by the chaotic evolution of the eccentricity (Correia & Laskar 2004). The second scenario includes friction at the core-mantle boundary, which increases the probabilities of capture during one crossing (Peale & Boss 1977, Correia & Laskar 2009). The third scenario assumes that Mercury had had a retrograde rotation, then a synchronous one, and only later came into the current 3:2 resonance. We here use a realistic model of tides, based on the Darwin-Kaula expansions combined with both the elastic rebound and anelastic creep of solids. Within this model, we find that the 3:2 spin-orbit resonance is the most probable for a homogeneous Mercury. Moreover, we find that leaving a resonance after being trapped is impossible or virtually impossible, thus excluding the possibility of a past 2:1 resonance. This also indicates that entrapment is likely to happen before the differentiation of Mercury takes place.

  15. Towards achieving strong coupling in three-dimensional-cavity with solid state spin resonance

    Science.gov (United States)

    Le Floch, J.-M.; Delhote, N.; Aubourg, M.; Madrangeas, V.; Cros, D.; Castelletto, S.; Tobar, M. E.

    2016-04-01

    We investigate the microwave magnetic field confinement in several microwave three-dimensional (3D)-cavities, using a 3D finite-element analysis to determine the best design and achieve a strong coupling between microwave resonant cavity photons and solid state spins. Specifically, we design cavities for achieving strong coupling of electromagnetic modes with an ensemble of nitrogen vacancy (NV) defects in diamond. We report here a novel and practical cavity design with a magnetic filling factor of up to 4 times (2 times higher collective coupling) than previously achieved using one-dimensional superconducting cavities with a small mode volume. In addition, we show that by using a double-split resonator cavity, it is possible to achieve up to 200 times better cooperative factor than the currently demonstrated with NV in diamond. These designs open up further opportunities for studying strong and ultra-strong coupling effects on spins in solids using alternative systems with a wider range of design parameters. The strong coupling of paramagnetic spin defects with a photonic cavity is used in quantum computer architecture, to interface electrons spins with photons, facilitating their read-out and processing of quantum information. To achieve this, the combination of collective coupling of spins and cavity mode is more feasible and offers a promising method. This is a relevant milestone to develop advanced quantum technology and to test fundamental physics principles.

  16. Magnetic field dependence of the neutron spin resonance in CeB6

    Science.gov (United States)

    Portnichenko, P. Y.; Demishev, S. V.; Semeno, A. V.; Ohta, H.; Cameron, A. S.; Surmach, M. A.; Jang, H.; Friemel, G.; Dukhnenko, A. V.; Shitsevalova, N. Yu.; Filipov, V. B.; Schneidewind, A.; Ollivier, J.; Podlesnyak, A.; Inosov, D. S.

    2016-07-01

    In zero magnetic field, the famous neutron spin resonance in the f -electron superconductor CeCoIn5 is similar to the recently discovered exciton peak in the nonsuperconducting CeB6. A magnetic field splits the resonance in CeCoIn5 into two components, indicating that it is a doublet. Here we employ inelastic neutron scattering (INS) to scrutinize the field dependence of spin fluctuations in CeB6. The exciton shows a markedly different behavior without any field splitting. Instead, we observe a second field-induced magnon whose energy increases with field. At the ferromagnetic zone center, however, we find only a single mode with a nonmonotonic field dependence. At low fields, it is initially suppressed to zero together with the antiferromagnetic order parameter, but then reappears at higher fields inside the hidden-order phase, following the energy of an electron spin resonance (ESR). This is a unique example of a ferromagnetic resonance in a heavy-fermion metal seen by both ESR and INS consistently over a broad range of magnetic fields.

  17. The Onset Of Resonance In Two-Immiscible Fluids Inside A Spinning And Coning Cylinder

    OpenAIRE

    Selmi, M

    1993-01-01

    Resonance of the motion of two fluids inside a cylinder that spins about its axis and rotates (cones) about an axis that passes through its center of mass is known to occur for low-viscosity fluids (high Reynolds number flows) at critical geometric parameters and coning frequencies. In this paper the motion of two inviscid fluids inside a spinning and coning cylinder is analyzed by the method of separation of variables for small coning frequencies and/or coning angles. The analytical solution...

  18. Pion-nucleus spin-flip strength at low and resonance energies

    International Nuclear Information System (INIS)

    Cross sections have been measured for 65 MeV π+ scattering to the 10B ground and first four excited states. The 1.74 MeV excited state results provide the first measurement of the energy dependence of the isovector spin-flip strength parameter. Our analysis indicates that the observed empirical enhancement of the isovector spin-flip strength has little or no dependence on energy at and below resonance. A mass dependence for the empirical enhancement factor may exist. copyright 1997 The American Physical Society

  19. Electron spin resonance study of Na_{1-x}Li_xV_2O_5

    OpenAIRE

    Lohmann, M.; von Nidda, H. -A. Krug; Loidl, A.; Morre, E.; Dischner, M.; Geibel, C

    1999-01-01

    We measured X-band electron-spin resonance of single crystalline sodium vanadate doped with lithium, Na_{1-x}Li_xV_2O_5 for 0 < x < 1.3% . The phase transition into a dimerized phase that is observed at 34 K in the undoped compound, was found to be strongly suppressed upon doping with lithium. The spin susceptibility was analyzed to determine the transition temperature and the energy gap with respect to the lithium content. The transition temperature Tsp is suppressed following a square depen...

  20. Spin-orbit driven ferromagnetic resonance: a nanoscale magnetic characterisation technique

    Czech Academy of Sciences Publication Activity Database

    Fang, D.; Kurebayashi, H.; Wunderlich, Joerg; Výborný, Karel; Zarbo, Liviu; Campion, R. P.; Casiraghi, A.; Gallagher, B. L.; Jungwirth, Tomáš; Ferguson, A.J.

    2011-01-01

    Roč. 6, č. 7 (2011), s. 413-417. ISSN 1748-3387 R&D Projects: GA AV ČR KAN400100652; GA MŠk LC510; GA AV ČR KJB100100802; GA MŠk(CZ) 7E08087 Grant ostatní: AVCR(CZ) Premium Academiae; 7 FP NAMASTE(XE) 214499; 7 FP SemiSpinNet(XE) 215368 Institutional research plan: CEZ:AV0Z10100521 Keywords : ferromagnetic resonance * spin-orbit coupling * nanomagnets Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 27.270, year: 2011

  1. The giant dipole resonance at high spin and moderate temperature

    International Nuclear Information System (INIS)

    The role of deformation, temperature and angular momentum in the evolution of the isovector giant dipole resonance (GDR) with excitation energy is studied. The dipole cross section is calculated applying a cranked Nilsson potential together with a separable dipole-dipole force. Calculations for 90Zr, 108Sn and 164Er are presented. For the last two nuclides, 108Sn and 164Er, the observed development of the damping width of the dipole intensity is explained by the evolution of the equilibrium deformation. 90Zr remains spherical at the E* studied, the thermal shape fluctuations being responsible of the broadening of the cross section. The effect of fluctuations on the angular distribution of the gamma-rays associated with the dipole emission, strongly depends on the free energy surface shape. (orig.)

  2. High-pressure magic angle spinning nuclear magnetic resonance.

    Science.gov (United States)

    Hoyt, David W; Turcu, Romulus V F; Sears, Jesse A; Rosso, Kevin M; Burton, Sarah D; Felmy, Andrew R; Hu, Jian Zhi

    2011-10-01

    A high-pressure magic angle spinning (MAS) NMR capability, consisting of a reusable high-pressure MAS rotor, a high-pressure rotor loading/reaction chamber for in situ sealing and re-opening of the high-pressure MAS rotor, and a MAS probe with a localized RF coil for background signal suppression, is reported. The unusual technical challenges associated with development of a reusable high-pressure MAS rotor are addressed in part by modifying standard ceramics for the rotor sleeve by abrading the internal surface at both ends of the cylinder. In this way, not only is the advantage of ceramic cylinders for withstanding very high-pressure utilized, but also plastic bushings can be glued tightly in place so that other removable plastic sealing mechanisms/components and O-rings can be mounted to create the desired high-pressure seal. Using this strategy, sealed internal pressures exceeding 150 bars have been achieved and sustained under ambient external pressure with minimal loss of pressure for 72 h. As an application example, in situ(13)C MAS NMR studies of mineral carbonation reaction intermediates and final products of forsterite (Mg(2)SiO(4)) reacted with supercritical CO(2) and H(2)O at 150 bar and 50°C are reported, with relevance to geological sequestration of carbon dioxide. PMID:21862372

  3. High-pressure Magic Angle Spinning Nuclear Magnetic Resonance

    International Nuclear Information System (INIS)

    A high-pressure magic angle spinning (MAS) NMR capability, consisting of a reusable high-pressure MAS rotor, a high-pressure loading/reaction chamber for in situ sealing and re-opening of the high-pressure MAS rotor, and a MAS probe with a localized RF coil for background signal suppression, is reported. The unusual technical challenges associated with development of a reusable high-pressure MAS rotor are addressed in part by modifying standard ceramics for the rotor sleeve to include micro-groves at the internal surface at both ends of the cylinder. In this way, not only is the advantage of ceramic cylinders for withstanding very high-pressure utilized, but also plastic bushings can be glued tightly in place so that other plastic sealing mechanisms/components and O-rings can be mounted to create the desired high-pressure seal. Using this strategy, sealed internal pressures exceeding 150 bars have been achieved and sustained under ambient external pressure with minimal penetration loss of pressure for 72 hours. As an application example, in situ 13C MAS NMR studies of mineral carbonation reaction intermediates and final products of forsterite (Mg2SiO4) reacted with supercritical CO2 and H2O at 150 bar and 50 C are reported, with relevance to geological sequestration of carbon dioxide.

  4. Antiferromagnetic ordering in spin-chain multiferroic Gd{sub 2}BaNiO{sub 5} studied by electronic spin resonance

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Y. M.; Ruan, M. Y.; Cheng, J. J.; Sun, Y. C. [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Ouyang, Z. W., E-mail: zwouyang@mail.hust.edu.cn; Xia, Z. C. [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Rao, G. H. [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541004 (China)

    2015-06-14

    High-field electron spin resonance (ESR) has been employed to study the antiferromagnetic (AFM) ordering state (T < T{sub N} = 55 K) of spin-chain multiferroic Gd{sub 2}BaNiO{sub 5}. The spin reorientation at T{sub SR} = 24 K is well characterized by the temperature-dependent ESR spectra. The magnetization data evidence a field-induced spin-flop transition at 2 K. The frequency-field relationship of the ESR data can be explained by conventional AFM resonance theory with uniaxial anisotropy, in good agreement with magnetization data. Related discussion on zero-field spin gap is presented.

  5. Spin–orbit interaction in bent carbon nanotubes: resonant spin transitions

    International Nuclear Information System (INIS)

    We develop an effective tight-binding Hamiltonian for spin–orbit (SO) interaction in bent carbon nanotubes (CNT) for the electrons forming the π bonds between the nearest neighbor atoms. We account for the bend of the CNT and the intrinsic spin–orbit interaction which introduce mixing of π and σ bonds between the p z orbitals along the CNT. The effect contributes to the main origin of the SO coupling—the folding of the graphene plane into the nanotube. We discuss the bend-related contribution of the SO coupling for resonant single-electron spin and charge transitions in a double quantum dot. We report that although the effect of the bend-related SO coupling is weak for the energy spectra, it produces a pronounced increase of the spin transition rates driven by an external electric field. We find that spin-flipping transitions driven by alternate electric fields have usually larger rates when accompanied by charge shift from one dot to the other. Spin-flipping transition rates are non-monotonic functions of the driving amplitude since they are masked by stronger spin-conserving charge transitions. We demonstrate that the fractional resonances—counterparts of multiphoton transitions for atoms in strong laser fields—occurring in electrically controlled nanodevices already at moderate ac amplitudes—can be used to maintain the spin-flip transitions. (paper)

  6. Non-resonant parametric restoration of microwave spin-wave signals in YIG films

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Sebastian; Chumak, Andrii V.; Serga, Alexander A.; Hillebrands, Burkard [FB Physik and FSP MINAS, TU Kaiserslautern, 67663 Kaiserslautern (Germany)

    2008-07-01

    We report on the storage and restoration of spin-wave pulses in a thin Yttrium-iron-garnet (YIG) film. A Damon-Eshbach (DE) type spin-wave pulse is irradiated by a microstrip antenna and excites perpendicular standing spin-wave modes (PSSW), existing due to the finite thickness of the film. Those modes are excited, where the crossing of DE and PSSW dispersions leads to a hybridization of both groups of magnons. After the DE pulse has left the area of interest, energy is provided to the magnonic system with the means of parallel parametric pumping. Here we focus on the dependence of the characteristics of recovered traveling spin-wave pulses on the intensity of the input microwave spin-wave signal for the non-resonant case where the pumping frequency does not match exactly twice the carrier frequency of the original DE mode. This enables the investigation of spectral characteristics of the input microwave spin-wave signal and is a basic step in order to understand the influence of the thermal bath and increasing of the thermal noise for the interaction between the magnon system and a parametric pumping field.

  7. Estimation of the Postmortem Duration of Mouse Tissue by Electron Spin Resonance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Shinobu Ito

    2011-01-01

    Full Text Available Electron spin resonance (ESR method is a simple method for detecting various free radicals simultaneously and directly. However, ESR spin trap method is unsuited to analyze weak ESR signals in organs because of water-induced dielectric loss (WIDL. To minimize WIDL occurring in biotissues and to improve detection sensitivity to free radicals in tissues, ESR cuvette was modified and used with 5,5-dimethtyl-1-pyrroline N-oxide (DMPO. The tissue samples were mouse brain, hart, lung, liver, kidney, pancreas, muscle, skin, and whole blood, where various ESR spin adduct signals including DMPO-ascorbyl radical (AsA∗, DMPO-superoxide anion radical (OOH, and DMPO-hydrogen radical (H signal were detected. Postmortem changes in DMPO-AsA∗ and DMPO-OOH were observed in various tissues of mouse. The signal peak of spin adduct was monitored until the 205th day postmortem. DMPO-AsA∗ in liver (y=113.8–40.7 log (day, R1=-0.779, R2=0.6, P<.001 was found to linearly decrease with the logarithm of postmortem duration days. Therefore, DMPO-AsA∗ signal may be suitable for detecting an oxidation stress tracer from tissue in comparison with other spin adduct signal on ESR spin trap method.

  8. An automated framework for NMR resonance assignment through simultaneous slice picking and spin system forming

    KAUST Repository

    Abbas, Ahmed

    2014-04-19

    Despite significant advances in automated nuclear magnetic resonance-based protein structure determination, the high numbers of false positives and false negatives among the peaks selected by fully automated methods remain a problem. These false positives and negatives impair the performance of resonance assignment methods. One of the main reasons for this problem is that the computational research community often considers peak picking and resonance assignment to be two separate problems, whereas spectroscopists use expert knowledge to pick peaks and assign their resonances at the same time. We propose a novel framework that simultaneously conducts slice picking and spin system forming, an essential step in resonance assignment. Our framework then employs a genetic algorithm, directed by both connectivity information and amino acid typing information from the spin systems, to assign the spin systems to residues. The inputs to our framework can be as few as two commonly used spectra, i.e., CBCA(CO)NH and HNCACB. Different from the existing peak picking and resonance assignment methods that treat peaks as the units, our method is based on \\'slices\\', which are one-dimensional vectors in three-dimensional spectra that correspond to certain (N, H) values. Experimental results on both benchmark simulated data sets and four real protein data sets demonstrate that our method significantly outperforms the state-of-the-art methods while using a less number of spectra than those methods. Our method is freely available at http://sfb.kaust.edu.sa/Pages/Software.aspx. © 2014 Springer Science+Business Media.

  9. Rashba coupling in three-dimensional wurtzite structure electron gas at electric-dipole spin resonance

    Science.gov (United States)

    Ungier, W.

    2014-05-01

    Theoretical description of Rashba effects in three-dimensional electron gas at electric-dipole spin resonance conditions is presented in the frame of conductivity tensor formalism. The details due to anisotropy of the effective mass tensor, as well as the Lande factor, are considered. The absorbed power is calculated for arbitrary orientation of the sample with respect to external fields: constant magnetic field and rf electric field. The differences between resonance signals in two- and three-dimensional electron gas are pointed out.

  10. Controlling nuclear spin exchange via optical Feshbach resonances in ${}^{171}$Yb

    OpenAIRE

    Reichenbach, Iris; Julienne, Paul S.; Deutsch, Ivan H.

    2009-01-01

    Nuclear spin exchange occurs in ultracold collisions of fermionic alkaline-earth-like atoms due to a difference between s- and p-wave phase shifts. We study the use of an optical Feshbach resonance, excited on the ${}^1S_0 \\to {}^3P_1$ intercombination line of ${}^{171}$Yb, to affect a large modification of the s-wave scattering phase shift, and thereby optically mediate nuclear exchange forces. We perform a full multichannel calculation of the photoassociation resonances and wave functions a...

  11. Spin transport, magnetoresistance, and electrically detected magnetic resonance in amorphous hydrogenated silicon nitride

    Science.gov (United States)

    Mutch, Michael J.; Lenahan, Patrick M.; King, Sean W.

    2016-08-01

    We report on a study of spin transport via electrically detected magnetic resonance (EDMR) and near-zero field magnetoresistance (MR) in silicon nitride films. Silicon nitrides have long been important materials in solid state electronics. Although electronic transport in these materials is not well understood, electron paramagnetic resonance studies have identified a single dominating paramagnetic defect and have also provided physical and chemical descriptions of the defects, called K centers. Our EDMR and MR measurements clearly link the near-zero field MR response to the K centers and also indicate that K center energy levels are approximately 3.1 eV above the a-SiN:H valence band edge. In addition, our results suggest an approach for the study of defect mediated spin-transport in inorganic amorphous insulators via variable electric field and variable frequency EDMR and MR which may be widely applicable.

  12. Quantifying charge resonance and multiexciton character in coupled chromophores by charge and spin cumulant analysis

    International Nuclear Information System (INIS)

    We extend excited-state structural analysis to quantify the charge-resonance and multi-exciton character in wave functions of weakly interacting chromophores such as molecular dimers. The approach employs charge and spin cumulants which describe inter-fragment electronic correlations in molecular complexes. We introduce indexes corresponding to the weights of local, charge resonance, and biexciton (with different spin structure) configurations that can be computed for general wave functions thus allowing one to quantify the character of doubly excited states. The utility of the approach is illustrated by applications to several small dimers, e.g., He-H2, (H2)2, and (C2H4)2, using full and restricted configuration interaction schemes. In addition, we present calculations for several systems relevant to singlet fission, such as tetracene, 1,6-diphenyl-1,3,5-hexatriene, and 1,3-diphenylisobenzofuran dimers

  13. Quantifying charge resonance and multiexciton character in coupled chromophores by charge and spin cumulant analysis

    Energy Technology Data Exchange (ETDEWEB)

    Luzanov, Anatoliy V. [STC “Institute for Single Crystals,” National Academy of Sciences, Kharkov 61001 (Ukraine); Casanova, David [Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC), P.K. 1072, 20080 Donostia (Spain); IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Euskadi (Spain); Feng, Xintian; Krylov, Anna I. [Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482 (United States)

    2015-06-14

    We extend excited-state structural analysis to quantify the charge-resonance and multi-exciton character in wave functions of weakly interacting chromophores such as molecular dimers. The approach employs charge and spin cumulants which describe inter-fragment electronic correlations in molecular complexes. We introduce indexes corresponding to the weights of local, charge resonance, and biexciton (with different spin structure) configurations that can be computed for general wave functions thus allowing one to quantify the character of doubly excited states. The utility of the approach is illustrated by applications to several small dimers, e.g., He-H{sub 2}, (H{sub 2}){sub 2}, and (C{sub 2}H{sub 4}){sub 2}, using full and restricted configuration interaction schemes. In addition, we present calculations for several systems relevant to singlet fission, such as tetracene, 1,6-diphenyl-1,3,5-hexatriene, and 1,3-diphenylisobenzofuran dimers.

  14. Quantifying charge resonance and multiexciton character in coupled chromophores by charge and spin cumulant analysis.

    Science.gov (United States)

    Luzanov, Anatoliy V; Casanova, David; Feng, Xintian; Krylov, Anna I

    2015-06-14

    We extend excited-state structural analysis to quantify the charge-resonance and multi-exciton character in wave functions of weakly interacting chromophores such as molecular dimers. The approach employs charge and spin cumulants which describe inter-fragment electronic correlations in molecular complexes. We introduce indexes corresponding to the weights of local, charge resonance, and biexciton (with different spin structure) configurations that can be computed for general wave functions thus allowing one to quantify the character of doubly excited states. The utility of the approach is illustrated by applications to several small dimers, e.g., He-H2, (H2)2, and (C2H4)2, using full and restricted configuration interaction schemes. In addition, we present calculations for several systems relevant to singlet fission, such as tetracene, 1,6-diphenyl-1,3,5-hexatriene, and 1,3-diphenylisobenzofuran dimers. PMID:26071698

  15. Optical rotation and electron spin resonance of an electro-optically active polythiophene

    International Nuclear Information System (INIS)

    Graphical abstract: The electro-chiroptical polythiophene displays optical rotation at wavelengths corresponding to the doping band observable in the absorption spectra. The formation of polarons on the main-chain is confirmed by electron spin resonance measurements. - Abstract: A chiroptical polythiophene, is synthesized by electrolytic polymerization in a cholesteric liquid crystal electrolyte solution. The polymer displays a fingerprint texture similar to that of the cholesteric electrolyte solution. Upon electrochemical doping, the polymer displays optical rotation at wavelengths corresponding to the doping band observable in the absorption spectra. The formation of polarons on the main-chain is confirmed by electron spin resonance measurements. The results demonstrate the intermolecular chirality of polarons in this π-conjugated polymer, indicating continuum delocalized polarons are in a three-dimensional helical environment.

  16. Spin-mixed doubly excited resonances in Ca and Sr spectra

    International Nuclear Information System (INIS)

    We present a joint theoretical and experimental investigation to demonstrate explicitly how the combined spin-dependent interaction and the configuration interaction may affect the mixing of different spin states along various doubly excited autoionization series for Ca and Sr as energy increases across several ionization thresholds. In particular, our study has identified the inversion of energy levels between members of a number of multiplets, i.e., in contrast to the Hund's rules, due to the presence of perturber from other overlapping resonance series. We are also able to demonstrate the beginning of the breakdown of the LS coupling for resonance series corresponding to electron configurations with higher orbital angular momenta and those above the third ionization threshold.

  17. New Techniques for Determining Spins and Parities of Neutron Resonances and Their Impact on Nuclear Astrophysics

    International Nuclear Information System (INIS)

    We describe new techniques for determining spins and parities of neutron resonances which have resulted in large improvements over previous methods. These advances have made it possible, for the first time, to obtain reduced-neutron- and total-radiation-width distributions separately for resonances of different spin and parity in odd-A target nuclides. Using these new as well as previous data, we show that neutron distributions sometimes are significantly different from the Porter-Thomas distribution assumed by the nuclear statistical model. Furthermore, we show that the radiation-width distributions often are substantially different than predicted by the nuclear statistical model using standard level densities and photon strength functions. These differences could have significant impact on astrophysical reaction rates calculated using the statistical model.

  18. Magnetic field splitting of the spin-resonance in CeCoIn5

    OpenAIRE

    Stock, C.; Broholm, C.; Zhao, Y.; Demmel, F; Kang, H. J.; Rule, K. C.; Petrovic, C.

    2012-01-01

    Neutron scattering in strong magnetic fields is used to show the spin-resonance in superconducting CeCoIn5 (Tc=2.3 K) is a doublet. The underdamped resonance (\\hbar \\Gamma=0.069 \\pm 0.019 meV) Zeeman splits into two modes at E_{\\pm}=\\hbar \\Omega_{0}\\pm g\\mu_{B} \\mu_{0}H with g=0.96 \\pm 0.05. A linear extrapolation of the lower peak reaches zero energy at 11.2 \\pm 0.5 T, near the critical field for the incommensurate "Q-phase" indicating that the Q-phase is a bose condensate of spin excitons.

  19. Magnetic field splitting of the spin resonance in CeCoIn5.

    Science.gov (United States)

    Stock, C; Broholm, C; Zhao, Y; Demmel, F; Kang, H J; Rule, K C; Petrovic, C

    2012-10-19

    Neutron scattering in strong magnetic fields is used to show the spin resonance in superconducting CeCoIn(5) (T(c)=2.3 K) is a doublet. The underdamped resonance (ħΓ=0.069±0.019 meV) Zeeman splits into two modes at E(±)=ħΩ(0)±αμ(B)μ(0)H with α=0.96±0.05. A linear extrapolation of the lower peak reaches zero energy at 11.2±0.5 T, near the critical field for the incommensurate "Q phase." Kenzelmann et al. [Science 321, 1652 (2008)] This, taken with the integrated weight and polarization of the low-energy mode (E(-)), indicates that the Q phase can be interpreted as a Bose condensate of spin excitons. PMID:23215124

  20. Resonant microwave cavity for 8.5-12 GHz optically detected electron spin resonance with simultaneous nuclear magnetic resonance

    Science.gov (United States)

    Colton, J. S.; Wienkes, L. R.

    2009-03-01

    We present a newly developed microwave resonant cavity for use in optically detected magnetic resonance (ODMR) experiments. The cylindrical quasi-TE011 mode cavity is designed to fit in a 1 in. magnet bore to allow the sample to be optically accessed and to have an adjustable resonant frequency between 8.5 and 12 GHz. The cavity uses cylinders of high dielectric material, so-called "dielectric resonators," in a double-stacked configuration to determine the resonant frequency. Wires in a pseudo-Helmholtz configuration are incorporated into the cavity to provide frequencies for simultaneous nuclear magnetic resonance (NMR). The system was tested by measuring cavity absorption as microwave frequencies were swept, by performing ODMR on a zinc-doped InP sample, and by performing optically detected NMR on a GaAs sample. The results confirm the suitability of the cavity for ODMR with simultaneous NMR.

  1. Electron spin resonance spectroscopy for the study of nanomaterial-mediated generation of reactive oxygen species

    Directory of Open Access Journals (Sweden)

    Weiwei He

    2014-03-01

    Full Text Available Many of the biological applications and effects of nanomaterials are attributed to their ability to facilitate the generation of reactive oxygen species (ROS. Electron spin resonance (ESR spectroscopy is a direct and reliable method to identify and quantify free radicals in both chemical and biological environments. In this review, we discuss the use of ESR spectroscopy to study ROS generation mediated by nanomaterials, which have various applications in biological, chemical, and materials science. In addition to introducing the theory of ESR, we present some modifications of the method such as spin trapping and spin labeling, which ultimately aid in the detection of short-lived free radicals. The capability of metal nanoparticles in mediating ROS generation and the related mechanisms are also presented.

  2. OBTAINING THE CRITICAL DRAW RATIO OF DRAW RESONANCE IN MELT SPINNING FOR POWER LAW POLYMER FLUIDS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A direct difference method has been developed for Non-Newtonian power law fluids to solve the simultaneous non-linear partial differential equations of melt spinning,and to determine the critical draw ratio for draw resonance.The results show that for shear thin fluids,the logarithm of the critical draw ratio has a well defined linear relationship with the power index for isothermal and uniform tension melt spinning.When the power index approaches zero,the critical draw ratio points at unity,indicating no melt spinning can be processed stably for such fluids.For shear thick fluids.the critical draw ratio increases in a more rapid Way with increasing the power index.

  3. Electron spin resonance and cyclotron resonance for fractional quantum Hall states in narrow-gap QW heterostructures

    International Nuclear Information System (INIS)

    We report a theoretical study of the energies of cyclotron resonance (CR) and electron spin resonance (ESR) for fractional quantum Hall states (FQHS) in n-type narrow-gap quantum well (QW) heterostructures. Using the generalized single-mode approximation (GSMA) based on the 8-band k ⋅p Hamiltonian, we calculate the many-body corrections to the CR and ESR energies for FQHS, providing theoretical evidence of the Kohn and Larmor theorem violation in narrow-gap QWs. We predict the correlation-induced reduction of CR energies and the correlation-induced enhancement of ESR energies as compared with the values obtained within the Hartree–Fock approximation. We demonstrate a nonlinear dependence of the CR and ESR energies on a Landau level filling factor. (paper)

  4. Electron doping evolution of the neutron spin resonance in NaFe$_{1-x}$Co$_{x}$As

    OpenAIRE

    Zhang, Chenglin; Lv, Weicheng; Tan, Guotai; Song, Yu; Carr, Scott V.; Chi, Songxue; Matsuda, M.; Christianson, A. D.; Fernandez-Baca, J. A.; Harriger, L. W.; Dai, Pengcheng

    2016-01-01

    Neutron spin resonance, a collective magnetic excitation coupled to superconductivity, is one of the most prominent features shared by a broad family of unconventional superconductors including copper oxides, iron pnictides, and heavy fermions. In this work, we study the doping evolution of the resonances in NaFe$_{1-x}$Co$_x$As covering the entire superconducting dome. For the underdoped compositions, two resonance modes coexist. As doping increases, the low-energy resonance gradually loses ...

  5. Electron paramagnetic resonance spectroscopy using a direct current-SQUID magnetometer directly coupled to an electron spin ensemble

    Science.gov (United States)

    Toida, Hiraku; Matsuzaki, Yuichiro; Kakuyanagi, Kosuke; Zhu, Xiaobo; Munro, William J.; Nemoto, Kae; Yamaguchi, Hiroshi; Saito, Shiro

    2016-02-01

    We demonstrate electron spin polarization detection and electron paramagnetic resonance (EPR) spectroscopy using a direct current superconducting quantum interference device (dc-SQUID) magnetometer. Our target electron spin ensemble is directly bonded to the dc-SQUID magnetometer that detects electron spin polarization induced by an external magnetic field or EPR in a micrometer-sized area. The minimum distinguishable number of polarized spins and sensing volume of the electron spin polarization detection and the EPR spectroscopy are estimated to be ˜106 and ˜10-10 cm3 (˜0.1 pl), respectively.

  6. Spin filter effect at room temperature in GaN/GaMnN ferromagnetic resonant tunnelling diode

    Science.gov (United States)

    Wójcik, P.; Adamowski, J.; Wołoszyn, M.; Spisak, B. J.

    2013-06-01

    We have investigated the spin current polarization without the external magnetic field in the resonant tunneling diode with the emitter and quantum well layers made from the ferromagnetic GaMnN. For this purpose, we have applied the self-consistent Wigner-Poisson method and studied the spin-polarizing effect for the parallel and antiparallel alignments of the magnetization of the ferromagnetic layers. The results of our calculations show that the antiparallel magnetization is much more advantageous for the spin filter operation and leads to the full spin current polarization at low temperatures and 35% spin polarization of the current at room temperature.

  7. Current-driven, electrically detected ferromagnetic resonance in electrodeposited spin valves

    International Nuclear Information System (INIS)

    We investigate the ferromagnetic resonance of Co/Cu/Co trilayers by use of AC-spin-transfer torque excitations. Magnetic structures are grown in a 6-μm-thick commercial nanoporous polycarbonate membranes by use of electrodeposition in a cobalt/copper single bath. We show that microwave magnetic excitations corresponding to the uniform mode of the two cobalt layers are electrically detected as a change of the DC voltage of the system.

  8. Integer spin resonance crossing at VEPP-4M with conservation of beam polarization

    CERN Document Server

    Barladyan, A K; Glukhov, S A; Glukhovchenko, Yu M; Karnaev, S E; Levichev, E B; Nikitin, S A; Nikolaev, I B; Okunev, I N; Piminov, P A; Shamov, A G; Zhuravlev, A N

    2015-01-01

    A recently proposed method to preserve the electron beam polarization at the VEPP-4M collider during acceleration with crossing the integer spin resonance energy E=1763 MeV has been successfully applied. It is based on full decompensation of $ 0.6\\times3.3$ Tesla$\\times$meter integral of the KEDR detector longitudinal magnetic field due to s 'switched-off' state of the anti-solenoids.

  9. Electron spin resonance of paramagnetic defects and related charge carrier traps in complex oxide scintillators

    Czech Academy of Sciences Publication Activity Database

    Laguta, Valentyn; Nikl, Martin

    2013-01-01

    Roč. 250, č. 2 (2013), s. 254-260. ISSN 0370-1972 R&D Projects: GA MŠk(CZ) LM2011029; GA ČR GAP204/12/0805; GA AV ČR IAA100100810 Grant ostatní: SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 Keywords : scintillators * point defects * electron spin resonance * polarons Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.605, year: 2013

  10. Electron Spin Resonance Spectroscopy: Application to Proof of Structure of Organic Ketones.

    Science.gov (United States)

    Russell, G A; Talaty, E R

    1965-05-28

    Many ketones containing an alpha-methylene group can be converted to alpha-diketone radical anions in dimethyl sulfoxide solution. The resulting radical anions can usually be unambiguously identified by electron spin resonance spectroscopy, and the structure of the starting ketone may be deduced, often without reference to model compounds. The technique is also applicable to alpha-diketones, alpha-bromoketones, and alpha-hydroxyketones. PMID:17748118

  11. Electron spin resonance study of the demagnetization fields of the ferromagnetic and paramagnetic films

    Directory of Open Access Journals (Sweden)

    I.I. Gimazov, Yu.I. Talanov

    2015-12-01

    Full Text Available The results of the electron spin resonance study of the La1-xCaxMnO3 manganite and the diphenyl-picrylhydrazyl thin films for the magnetic field parallel and perpendicular to plane of the films are presented. The temperature dependence of the demagnetizing field is obtained. The parameters of the Curie-Weiss law are estimated for the paramagnetic thin film.

  12. Magnetic resonance findings in amyotrophic lateral sclerosis using a spin echo magnetization transfer sequence: preliminary report

    Directory of Open Access Journals (Sweden)

    ROCHA ANTÔNIO JOSÉ DA

    1999-01-01

    Full Text Available We present the magnetic resonance (MR findings of five patients with amyotrophic lateral sclerosis (ALS using a spin-echo sequence with an additional magnetization transfer (MT pulse on T1-weighted images (T1 SE/MT. These findings were absent in the control group and consisted of hyperintensity of the corticospinal tract. Moreover we discuss the principles and the use of this fast but simple MR technique in the diagnosis of ALS

  13. Studies of phospholipid hydration by high-resolution magic-angle spinning nuclear magnetic resonance.

    OpenAIRE

    Zhou, Z.; Sayer, B G; Hughes, D. W.; Stark, R E; Epand, R M

    1999-01-01

    A sample preparation method using spherical glass ampoules has been used to achieve 1.5-Hz resolution in 1H magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectra of aqueous multilamellar dispersions of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), serving to differentiate between slowly exchanging interlamellar and bulk water and to reveal new molecular-level information about hydration phenomena in these model biolo...

  14. Electron spin resonance measurement of radical scavenging activity of Aronia melanocarpa fruit juice

    OpenAIRE

    Stefka Valcheva-Kuzmanova; Branka Blagovic; Srecko Valic

    2012-01-01

    Background: The fruits of Aronia melanocarpa (Michx.) Elliot contain large amounts of phenolic substances, mainly procyanidins, anthocyanins and other flavonoids, and phenolic acids. The ability of phenolic substances to act as antioxidants has been well established. Objective: In this study, we investigated the radical scavenging activity of A. melanocarpa fruit juice (AMFJ). Materials and Methods: The method used was electron spin resonance (ESR) spectroscopy. The galvinoxyl free radical wa...

  15. Effects of magnetohydrodynamics matter density fluctuations on the solar neutrino resonant spin-flavor precession

    OpenAIRE

    Reggiani, N.; Guzzo, M. M.; Colonia, J. H.; de Holanda, P. C.

    1998-01-01

    Taking into account the stringent limits from helioseismology observations on possible matter density fluctuations described by magnetohydrodynamics theory, we find the corresponding time variations of solar neutrino survival probability due to the resonant spin-flavor precession phenomenon with amplitude of order O(10%). We discuss the physics potential of high statistics real time experiments, like as Superkamiokande, to observe the effects of such magnetohydrodynamics fluctuations on their...

  16. Spin-dependent electron transport through a magnetic resonant tunneling diode

    OpenAIRE

    Havu, P.; Tuomisto, N.; R. Väänänen; Puska, Martti J.; Nieminen, Risto M.

    2005-01-01

    Electron-transport properties in nanostructures can be modeled, for example, by using the semiclassical Wigner formalism or the quantum-mechanical Green’s function formalism. We compare the performance and the results of these methods in the case of magnetic resonant-tunneling diodes. We have implemented the two methods within the self-consistent spin-density-functional theory. Our numerical implementation of the Wigner formalism is based on the finite-difference scheme whereas for the Green’...

  17. Electrical Detection of Electron Spin Resonance in Microcrystalline Silicon pin Solar Cells

    OpenAIRE

    Behrends, Jan; Schnegg, Alexander; Fehr, Matthias; Lambertz, Andreas; Haas, Stefan; F. Finger; Rech, Bernd; Lips, Klaus

    2009-01-01

    Abstract Pulsed electrically detected magnetic resonance (pEDMR) was employed to study spin-dependent processes that influence charge transport in microcrystalline (?c-Si:H) pin solar cells. Special emphasis was put on the identification of the signals with respect to the individual layers of the cell structure. For this to achieve, we systematically modulated the morphology of the highly doped n- and p-layers from amorphous to microcrystalline. By combining the information obtaine...

  18. E1 transitions between spin-dipole and Gamow-Teller giant resonances

    CERN Document Server

    Rodin, V A

    2000-01-01

    The branching ratios for E1 transitions between the spin-dipole (SD) and Gamow-Teller (GT) giant resonances in $^{90}$Nb and $^{208}$Pb are evaluated. Assuming the main GT-state has the wave function close to that for the "ideal" GT-state, we reduced the problem to calculate the SD and GT strength functions. These strength functions are evaluated within an extended continuum-RPA approach.

  19. Neutron resonance spin-echo upgrade at the three-axis spectrometer FLEXX

    Energy Technology Data Exchange (ETDEWEB)

    Groitl, F., E-mail: felix.groitl@psi.ch; Quintero-Castro, D. L.; Habicht, K. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Keller, T. [Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart (Germany); Max Planck Society, Outstation at the MLZ, Lichtenbergstrasse 1, 85748 Garching (Germany)

    2015-02-15

    We describe the upgrade of the neutron resonance spin-echo setup at the cold neutron triple-axis spectrometer FLEXX at the BER II neutron source at the Helmholtz-Zentrum Berlin. The parameters of redesigned key components are discussed, including the radio frequency (RF) spin-flip coils, the magnetic shield, and the zero field coupling coils. The RF-flippers with larger beam windows allow for an improved neutron flux transfer from the source to the sample and further to the analyzer. The larger beam cross sections permit higher coil inclination angles and enable measurements on dispersive excitations with a larger slope of the dispersion. Due to the compact design of the spin-echo units in combination with the increased coil tilt angles, the accessible momentum-range in the Larmor diffraction mode is substantially enlarged. In combination with the redesigned components of the FLEXX spectrometer, including the guide, the S-bender polarizer, the double focusing monochromator, and a Heusler crystal analyzer, the count rate increased by a factor of 15.5, and the neutron beam polarization is enhanced. The improved performance extends the range of feasible experiments, both for inelastic scattering on excitation lifetimes in single crystals, and for high-resolution Larmor diffraction. The experimental characterization of the instrument components demonstrates the reliable performance of the new neutron resonance spin-echo option, now available for the scientific community at FLEXX.

  20. The theory of secondary resonances in the spin-orbit problem

    CERN Document Server

    Gkolias, Ioannis; Efthymiopoulos, Christos; Pucacco, Giuseppe

    2016-01-01

    We study the resonant dynamics in a simple one degree of freedom, time dependent Hamiltonian model describing spin-orbit interactions. The equations of motion admit periodic solutions associated with resonant motions, the most important being the synchronous one in which most evolved satellites of the Solar system, including the Moon, are observed. Such primary resonances can be surrounded by a chain of smaller islands which one refers to as secondary resonances. Here, we propose a novel canonical normalization procedure allowing to obtain a higher order normal form, by which we obtain analytical results on the stability of the primary resonances as well as on the bifurcation thresholds of the secondary resonances. The procedure makes use of the expansion in a parameter, called the detuning, measuring the shift from the exact secondary resonance. Also, we implement the so-called `book-keeping' method, i.e., the introduction of a suitable separation of the terms in orders of smallness in the normal form constr...

  1. Measurement of Antioxidant Capacity by Electron Spin Resonance Spectroscopy Based on Copper(II) Reduction.

    Science.gov (United States)

    Li, Dan; Jiang, Jia; Han, Dandan; Yu, Xinyu; Wang, Kun; Zang, Shuang; Lu, Dayong; Yu, Aimin; Zhang, Ziwei

    2016-04-01

    A new method is proposed for measuring the antioxidant capacity by electron spin resonance spectroscopy based on the loss of electron spin resonance signal after Cu(2+) is reduced to Cu(+) with antioxidant. Cu(+) was removed by precipitation in the presence of SCN(-). The remaining Cu(2+) was coordinated with diethyldithiocarbamate, extracted into n-butanol and determined by electron spin resonance spectrometry. Eight standards widely used in antioxidant capacity determination, including Trolox, ascorbic acid, ferulic acid, rutin, caffeic acid, quercetin, chlorogenic acid, and gallic acid were investigated. The standard curves for determining the eight standards were plotted, and results showed that the linear regression correlation coefficients were all high enough (r > 0.99). Trolox equivalent antioxidant capacity values for the antioxidant standards were calculated, and a good correlation (r > 0.94) between the values obtained by the present method and cupric reducing antioxidant capacity method was observed. The present method was applied to the analysis of real fruit samples and the evaluation of the antioxidant capacity of these fruits. PMID:26927869

  2. Electron spin resonance in thin film silicon after low temperature electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Astakhov, O. [Forschungszentrum Juelich, Institute of Photovoltaics, 52425 Juelich (Germany); National Science Center-Kharkov Institute of Physics and Technology, Institute of Materials Science and Technology, 61108, Kharkov (Ukraine)], E-mail: o.astakhov@fz-juelich.de; Finger, F.; Carius, R.; Lambertz, A. [Forschungszentrum Juelich, Institute of Photovoltaics, 52425 Juelich (Germany); Petrusenko, Yu.; Borysenko, V.; Barankov, D. [National Science Center-Kharkov Institute of Physics and Technology, Institute of Materials Science and Technology, 61108, Kharkov (Ukraine)

    2007-07-16

    Paramagnetic defects in amorphous and microcrystalline silicon (a-Si:H and {mu}c-Si:H) with various structure compositions and doping levels were investigated by electron spin resonance (ESR). Samples were prepared by PECVD. The defect density was varied with 2 MeV electron bombardment at 100 K and stepwise annealing in the range of 80 K-433 K. In intrinsic material the spin density of the dominant ESR signal, presumably originating from dangling bonds (db), increases by up to 3 orders of magnitude after irradiation. In doped {mu}c-Si:H material the pronounced conduction electron (CE) resonance disappears after irradiation and is replaced by the db resonance like in the irradiated intrinsic material. Generally the initial spin density and the line shape can be restored upon annealing at 433 K. Additional features at g-values of g {approx} 2.010 and g {approx} 2.000 in the ESR spectra are observed after irradiation together with the strongly enhanced Si db line at about g = 2.004-2.005. These features decrease rapidly on the first annealing steps and cannot be observed after the final annealing stage.

  3. Spin-symmetry conversion in methyl rotors induced by tunnel resonance at low temperature

    International Nuclear Information System (INIS)

    Field-cycling NMR in the solid state at low temperature (4.2 K) has been employed to measure the tunneling spectra of methyl (CH3) rotors in phenylacetone and toluene. The phenomenon of tunnel resonance reveals anomalies in 1H magnetization from which the following tunnel frequencies have been determined: phenylacetone, νt = 6.58 ± 0.08 MHz; toluene, νt(1) = 6.45 ± 0.06 GHz and νt(2) = 7.07 ± 0.06 GHz. The tunnel frequencies in the two samples differ by three orders of magnitude, meaning different experimental approaches are required. In phenylacetone the magnetization anomalies are observed when the tunnel frequency matches one or two times the 1H Larmor frequency. In toluene, doping with free radicals enables magnetization anomalies to be observed when the tunnel frequency is equal to the electron spin Larmor frequency. Cross-polarization processes between the tunneling and Zeeman systems are proposed and form the basis of a thermodynamic model to simulate the tunnel resonance spectra. These invoke space-spin interactions to drive the changes in nuclear spin-symmetry. The tunnel resonance lineshapes are explained, showing good quantitative agreement between experiment and simulations

  4. Transport through a triple quantum dot system: Formation of resonance band and its application as a spin filter

    Energy Technology Data Exchange (ETDEWEB)

    He, Zelong [Institute of Condensed-Matter Science and Technology, Harbin Institute of Technology, Harbin 150080 (China); Institute of Optoelectronic Technology, Heilongjiang Institute of Technology, Harbin 150050 (China); Lü, Tianquan, E-mail: ltq@hit.edu.cn [Institute of Condensed-Matter Science and Technology, Harbin Institute of Technology, Harbin 150080 (China)

    2012-07-23

    A three-quantum-dot spin filter based on nonequilibrium Green's function technique is proposed with external magnetic flux, Rashba spin orbit interaction, and intradot coulomb interaction taken into consideration. Numerical results indicate a spin filter can be made efficient by adjusting external magnetic flux and Rashba spin orbit interaction. Moreover, the formation of a resonance band is discussed through calculation. It is observed that the possibility of transition from one peak to other three peaks in the conductance spectrum increases with increasing interdot coupling strength. -- Highlights: ► Investigation of the conductance through a triple quantum dot system. ► Proposal of an efficient spin-filter device. ► Discussion on the formation of the resonance band. ► Study on spin polarization with intradot Coulomb interaction taken into consideration.

  5. Advances and applications of dynamic-angle spinning nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Baltisberger, J.H.

    1993-06-01

    This dissertation describes nuclear magnetic resonance experiments and theory which have been developed to study quadrupolar nuclei (those nuclei with spin greater than one-half) in the solid state. Primarily, the technique of dynamic-angle spinning (DAS) is extensively reviewed and expanded upon in this thesis. Specifically, the improvement in both the resolution (two-dimensional pure-absorptive phase methods and DAS angle choice) and sensitivity (pulse-sequence development), along with effective spinning speed enhancement (again through choice of DAS conditions or alternative multiple pulse schemes) of dynamic-angle spinning experiment was realized with both theory and experimental examples. The application of DAS to new types of nuclei (specifically the {sup 87}Rb and {sup 85}Rb nuclear spins) and materials (specifically amorphous solids) has also greatly expanded the possibilities of the use of DAS to study a larger range of materials. This dissertation is meant to demonstrate both recent advances and applications of the DAS technique, and by no means represents a comprehensive study of any particular chemical problem.

  6. Advances and applications of dynamic-angle spinning nuclear magnetic resonance

    International Nuclear Information System (INIS)

    This dissertation describes nuclear magnetic resonance experiments and theory which have been developed to study quadrupolar nuclei (those nuclei with spin greater than one-half) in the solid state. Primarily, the technique of dynamic-angle spinning (DAS) is extensively reviewed and expanded upon in this thesis. Specifically, the improvement in both the resolution (two-dimensional pure-absorptive phase methods and DAS angle choice) and sensitivity (pulse-sequence development), along with effective spinning speed enhancement (again through choice of DAS conditions or alternative multiple pulse schemes) of dynamic-angle spinning experiment was realized with both theory and experimental examples. The application of DAS to new types of nuclei (specifically the 87Rb and 85Rb nuclear spins) and materials (specifically amorphous solids) has also greatly expanded the possibilities of the use of DAS to study a larger range of materials. This dissertation is meant to demonstrate both recent advances and applications of the DAS technique, and by no means represents a comprehensive study of any particular chemical problem

  7. Study on the energy dependence of spin-spin correlation in the range of diproton resonances

    International Nuclear Information System (INIS)

    Coefficients of polarization correlation Csub(NN) (90 deg) at 9 values of energy in the 550-950 MeV range with absolute error less than 0.05 are measured on the beams on JINR and LINP synchrocyclotrons. Csub(NN) values at the angles of 41 deg, 69 deg, 77 deg (T=550, 610, 630 MeV) and 50 deg at other energies have been obtained. The measurement results are presented together with predictions of the Arndt phase analysis and two variants of the Hoshizaki analysis conducted before and after publishing the results of the given experiment. Energy dependence of Csub(NN) (50 deg) does not reveal noticeable peculiarities and it well agrees with all the variants of the analysis. The considered total data do not substantiate certain conclusions on resonance character in pp interaction in the investigated energy range. The structure observed in respect to Csub(NN) (90 deg, p) is the consequence of different energy dependence of amplitudes of triplet and singlet scattering and it may be interpreted as a testify to presence of resonance or as a consequence of threshold phenomena in inelastic channels in the 550-750 MeV energy range

  8. Observation of spin-dependent quantum well resonant tunneling in textured CoFeB layers

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, J. M., E-mail: jmteixeira@fc.up.pt; Costa, J. D.; Ventura, J.; Sousa, J. B. [IFIMUP and IN-Institute of Nanoscience and Nanotechnology, and Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Wisniowski, P. [Department of Electronics, AGH University of Science and Technology, 30-059 Krakow (Poland); Freitas, P. P. [INESC-MN and IN-Institute of Nanoscience and Nanotechnology, Rua Alves Redol, 9-1, 1000-029 Lisbon (Portugal)

    2014-03-17

    We report the observation of spin-dependent quantum well (QW) resonant tunneling in textured CoFeB free layers of single MgO magnetic tunnel junctions (MTJs). The inelastic electron tunneling spectroscopy spectra clearly show the presence of resonant oscillations in the parallel configuration, which are related with the appearance of majority-spin Δ{sub 1} QW states in the CoFeB free layer. To gain a quantitative understanding, we calculated QW state positions in the voltage-thickness plane using the so-called phase accumulation model (PAM) and compared the PAM solutions with the experimental resonant voltages observed for a set of MTJs with different CoFeB free layer thicknesses (t{sub fl} = 1.55, 1.65, 1.95, and 3.0 nm). An overall good agreement between experiment and theory was obtained. An enhancement of the tunnel magnetoresistance with bias is observed in a bias voltage region corresponding to the resonant oscillations.

  9. Non-local detection of spin dynamics via spin rectification effect in yttrium iron garnet/SiO2/NiFe trilayers near simultaneous ferromagnetic resonance

    Science.gov (United States)

    Soh, Wee Tee; Peng, Bin; Ong, C. K.

    2015-08-01

    The spin rectification effect (SRE), a phenomenon that generates dc voltages from ac microwave fields incident onto a conducting ferromagnet, has attracted widespread attention due to its high sensitivity to ferromagnetic resonance (FMR) as well as its relevance to spintronics. Here, we report the non-local detection of yttrium iron garnet (YIG) spin dynamics by measuring SRE voltages from an adjacent conducting NiFe layer up to 200 nm thick. In particular, we detect, within the NiFe layer, SRE voltages stemming from magnetostatic surface spin waves (MSSWs) of the adjacent bulk YIG which are excited by a shorted coaxial probe. These non-local SRE voltages within the NiFe layer that originates from YIG MSSWs are present even in 200 nm-thick NiFe films with a 50 nm thick SiO2 spacer between NiFe and YIG, thus strongly ruling out the mechanism of spin-pumping induced inverse spin Hall effect in NiFe as the source of these voltages. This long-range influence of YIG dynamics is suggested to be mediated by dynamic fields generated from YIG spin precession near YIG/NiFe interface, which interacts with NiFe spins near the simultaneous resonance of both spins, to generate a non-local SRE voltage within the NiFe layer.

  10. Non-local detection of spin dynamics via spin rectification effect in yttrium iron garnet/SiO{sub 2}/NiFe trilayers near simultaneous ferromagnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Soh, Wee Tee, E-mail: a0046479@u.nus.edu; Ong, C. K. [Center for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551 (Singapore); Peng, Bin [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2015-08-15

    The spin rectification effect (SRE), a phenomenon that generates dc voltages from ac microwave fields incident onto a conducting ferromagnet, has attracted widespread attention due to its high sensitivity to ferromagnetic resonance (FMR) as well as its relevance to spintronics. Here, we report the non-local detection of yttrium iron garnet (YIG) spin dynamics by measuring SRE voltages from an adjacent conducting NiFe layer up to 200 nm thick. In particular, we detect, within the NiFe layer, SRE voltages stemming from magnetostatic surface spin waves (MSSWs) of the adjacent bulk YIG which are excited by a shorted coaxial probe. These non-local SRE voltages within the NiFe layer that originates from YIG MSSWs are present even in 200 nm-thick NiFe films with a 50 nm thick SiO{sub 2} spacer between NiFe and YIG, thus strongly ruling out the mechanism of spin-pumping induced inverse spin Hall effect in NiFe as the source of these voltages. This long-range influence of YIG dynamics is suggested to be mediated by dynamic fields generated from YIG spin precession near YIG/NiFe interface, which interacts with NiFe spins near the simultaneous resonance of both spins, to generate a non-local SRE voltage within the NiFe layer.

  11. Non-local detection of spin dynamics via spin rectification effect in yttrium iron garnet/SiO2/NiFe trilayers near simultaneous ferromagnetic resonance

    International Nuclear Information System (INIS)

    The spin rectification effect (SRE), a phenomenon that generates dc voltages from ac microwave fields incident onto a conducting ferromagnet, has attracted widespread attention due to its high sensitivity to ferromagnetic resonance (FMR) as well as its relevance to spintronics. Here, we report the non-local detection of yttrium iron garnet (YIG) spin dynamics by measuring SRE voltages from an adjacent conducting NiFe layer up to 200 nm thick. In particular, we detect, within the NiFe layer, SRE voltages stemming from magnetostatic surface spin waves (MSSWs) of the adjacent bulk YIG which are excited by a shorted coaxial probe. These non-local SRE voltages within the NiFe layer that originates from YIG MSSWs are present even in 200 nm-thick NiFe films with a 50 nm thick SiO2 spacer between NiFe and YIG, thus strongly ruling out the mechanism of spin-pumping induced inverse spin Hall effect in NiFe as the source of these voltages. This long-range influence of YIG dynamics is suggested to be mediated by dynamic fields generated from YIG spin precession near YIG/NiFe interface, which interacts with NiFe spins near the simultaneous resonance of both spins, to generate a non-local SRE voltage within the NiFe layer

  12. Non-local detection of spin dynamics via spin rectification effect in yttrium iron garnet/SiO2/NiFe trilayers near simultaneous ferromagnetic resonance

    Directory of Open Access Journals (Sweden)

    Wee Tee Soh

    2015-08-01

    Full Text Available The spin rectification effect (SRE, a phenomenon that generates dc voltages from ac microwave fields incident onto a conducting ferromagnet, has attracted widespread attention due to its high sensitivity to ferromagnetic resonance (FMR as well as its relevance to spintronics. Here, we report the non-local detection of yttrium iron garnet (YIG spin dynamics by measuring SRE voltages from an adjacent conducting NiFe layer up to 200 nm thick. In particular, we detect, within the NiFe layer, SRE voltages stemming from magnetostatic surface spin waves (MSSWs of the adjacent bulk YIG which are excited by a shorted coaxial probe. These non-local SRE voltages within the NiFe layer that originates from YIG MSSWs are present even in 200 nm-thick NiFe films with a 50 nm thick SiO2 spacer between NiFe and YIG, thus strongly ruling out the mechanism of spin-pumping induced inverse spin Hall effect in NiFe as the source of these voltages. This long-range influence of YIG dynamics is suggested to be mediated by dynamic fields generated from YIG spin precession near YIG/NiFe interface, which interacts with NiFe spins near the simultaneous resonance of both spins, to generate a non-local SRE voltage within the NiFe layer.

  13. Spin dependent resonant tunneling through 6 micron diameter double barrier resonant tunneling diode

    OpenAIRE

    Fang, Z. L.; P. Wu; Kundtz, N.; Chang, A M; X.Y. Liu; Furdyna, J K

    2007-01-01

    A vertical resonant tunneling diode (RTD) based on the paramagnetic Zn1-x-yMnyCdxSe system has been fabricated with a pillar diameter down to ~ 6 micron. The diode exhibits high quality resonant tunneling characteristics through the electron sub-band of the quantum well at a temperature of 4.2K, where a clear phonon replica was observable in addition to the primary peak. Both peaks show a giant Zeeman splitting in an applied magnetic field. Employing a self-consistent real-time Green's functi...

  14. Note on renormalization of the spin-1 resonance propagator at one loop order

    CERN Document Server

    Kampf, Karol; Trnka, Jaroslav

    2009-01-01

    We study various aspects of the renormalization of the Resonance Chiral Theory at the one-loop level using a spin-one resonance propagator as a concrete example. We calculate explicitly the one-loop self-energy within the antisymmetric tensor field formalism, briefly discuss the general structure of the corresponding propagator obtained by means of the Dyson re-summation and give a classification of the propagating degrees of freedom. We find that additional pathological poles (negative norm ghosts or tachyons) are unavoidably generated and various scenarios according to their position are possible. We also briefly comment on the eventual dynamical generation of the opposite parity resonances which are frozen at the tree level and discuss the role of appropriate symmetry which could prevent such a scenario.

  15. Non-resonant wave front reversal of spin waves used for microwave signal processing

    Energy Technology Data Exchange (ETDEWEB)

    Vasyuchka, V I; Chumak, A V; Hillebrands, B [Fachbereich Physik and Forschungszentrum OPTIMAS, Technische Universitaet Kaiserslautern, 67663 Kaiserslautern (Germany); Melkov, G A; Moiseienko, V A [Department of Radiophysics, National Taras Shevchenko University of Kiev, 01033 Kiev (Ukraine); Slavin, A N, E-mail: vasyuchka@physik.uni-kl.d [Department of Physics, Oakland University, Rochester, MI 48309 (United States)

    2010-08-18

    It is demonstrated that non-resonant ({omega}{sub s} {ne} {omega}{sub p}/2) wave front reversal (WFR) of spin-wave pulses (carrier frequency {omega}{sub s}) caused by pulsed parametric pumping (carrier frequency {omega}{sub p}) can be effectively used for microwave signal processing. When the spectral width {Omega}{sub s} of the signal is wider than the frequency band {Omega}{sub p} of signal amplification by pumping ({Omega}{sub s} >> {Omega}{sub p}), the non-resonant WFR can be used for the analysis of the signal spectrum. In the opposite case ({Omega}{sub s} << {Omega}{sub p}) the non-resonant WFR can be used for active (with amplification) filtering of the input signal.

  16. Impurity color centers in quartz and trapped electron dating - Electron spin resonance, thermoluminescence studies.

    Science.gov (United States)

    Mcmorris, D. W.

    1971-01-01

    Investigation of impurity-related electron-hole traps that are known to be sensitive to ionizing radiations. Electron spin resonance (ESR) equivalent natural doses were determined for the Al hole trap in virgin specimens; the doses agreed with estimates based on published data for the Ge electron trap. The 0.17 deg/sec 180 and 300 C thermoluminescence (TL) peaks in natural specimens were found to have activation energies approximately correct for the Ge trap. The 300 C peak was also found to be correlated with annealing of the Ge electron resonance in gamma-irradiated, step-annealed specimens. Although the 300 C peak occurs in virgin specimens, the corresponding natural Ge electron resonance was not observed.

  17. Structure and decay properties of spin-dipole giant resonances within a semimicroscopical approach

    CERN Document Server

    Moukhai, E A; Urin, M H

    1999-01-01

    A semimicroscopical approach is applied to calculate: (i) strength functions for the charge-exchange spin-dipole giant resonances in the 208Pb parent nucleus; (ii) partial and total branching ratios for the direct proton decay of the resonance in 208Bi. The approach is based on continuum-RPA calculations of corresponding reaction-amplitudes and phenomenological description of the doorway-state coupling to many-quasiparticle configurations. The only adjustable parameter needed for the description is found by comparison of the calculated and experimental total widths of the resonance. Other model parameters used in calculations are taken from independent data. The calculated total branching ratio is found to be in reasonable agreement with the experimental value.

  18. Many-body effects in electron spin resonance in 2D systems with Rashba spin-orbit interaction

    International Nuclear Information System (INIS)

    We report effects of electron–electron (e–e) interaction on electron spin resonance (ESR) in two-dimensional (2D) systems with Rashba spin–orbit interaction (SOI). Using the Hartree–Fock approximation, we demonstrate that Rashba SOI results in non-zero many-body corrections to the ESR energy. We discover that e–e interaction in 2D systems with SOI can not only enhance the ESR energy but also lead to the ESR energy reduction. The magnitude of this effect exhibits remarkable features in a wide range of parameters relevant to experiment: it is found to be rather sensitive to the sign of g-factor and the filling factor of Landau levels ν. We derive analytical expressions for many-body corrections to ESR energy and energy dispersion of spin wave excitations for the case of ν⩽2. We have found out that e–e interaction does not affect the ESR energy in the case of filling of the lowest Landau level (ν⩽1) in 2D systems with positive g-factors even at arbitrarily large values of Rashba constant. The many-body renormalization of ESR energy in the case of fractional Quantum Hall effect is also discussed. (papers)

  19. Single-pulse terahertz coherent control of spin resonance in the canted antiferromagnet YFeO3, mediated by dielectric anisotropy

    DEFF Research Database (Denmark)

    Jin, Zuanming; Mics, Zoltán; Ma, Guohong;

    2013-01-01

    We report on the coherent control of terahertz (THz) spin waves in a canted antiferromagnet yttrium orthoferrite, YFeO3, associated with a quasiferromagnetic (quasi-FM) spin resonance at a frequency of 0.3 THz, using a single-incident THz pulse. The spin resonance is excited impulsively by the ma...

  20. Fingerprints of entangled spin and orbital physics in itinerant ferromagnets via angle-resolved resonant photoemission

    Science.gov (United States)

    Da Pieve, F.

    2016-01-01

    A method for mapping the local spin and orbital nature of the ground state of a system via corresponding flip excitations is proposed based on angle-resolved resonant photoemission and related diffraction patterns, obtained here via an ab initio modified one-step theory of photoemission. The analysis is done on the paradigmatic weak itinerant ferromagnet bcc Fe, whose magnetism, a correlation phenomenon given by the coexistence of localized moments and itinerant electrons, and the observed non-Fermi-Liquid behavior at extreme conditions both remain unclear. The combined analysis of energy spectra and diffraction patterns offers a mapping of local pure spin-flip, entangled spin-flip-orbital-flip excitations and chiral transitions with vortexlike wave fronts of photoelectrons, depending on the valence orbital symmetry and the direction of the local magnetic moment. Such effects, mediated by the hole polarization, make resonant photoemission a promising tool to perform a full tomography of the local magnetic properties even in itinerant ferromagnets or macroscopically nonmagnetic systems.

  1. Spin-Wave Resonance and Relaxation in CoFeB/Cr Superlattices

    Science.gov (United States)

    Gong, Yu; Cevher, Zehra; Ren, Yuhang; Imrane, Hassan; Sun, Nian X.

    2009-03-01

    We investigated the magnetic anisotropic properties and the spin wave relaxation in ten periods of CoFeB/Cr/CoFeB films grown on seed layers of Cu (˜ 5 nm) with Co : Fe : B composition ratio as 2:2:1. The measurements were taken in samples with 50-angstrom layers of CoFeB using both the time-resolved pump-probe magneto-optical sampling and the ferromagnetic resonance techniques. The thickness of the Cr interlayers ranges from 4-angstrom to 40-angstrom for investigating the mechanisms of interlayer coupling and exchange interactions. Both the acoustic branch and the optical branch in spin wave resonance spectra are identified. We determine the magnetic anisotropic parameters by measuring spin wave frequency as a function of external magnetic field in the time domain and by orthogonally rotating the field aligned axis with respect to the spectral field in the frequency domain. Moreover, we estimate the intrinsic Gilbert damping for the in-plane magnetization orientation. When the interlayer coupling is weaker, the damping increases significantly.

  2. Spin determination of heavy s-channel diphoton resonances at the LHC

    International Nuclear Information System (INIS)

    Diphoton events at the LHC can provide clean signals of heavy neutral quantum states predicted by New Physics models. These non-standard particles would manifest themselves by s-channel peaks in inclusive distributions in the diphoton invariant mass. Once discovered, the quantum numbers of such a diphoton resonance need to be determined in order to identify the associated non-standard physics, in the first place the spin by an angular analysis of the events. We here discuss this problem by comparing, as competing sources of a diphoton resonance, the spin-2 Randall-Sundrum graviton excitation and a spin-0 scalar exchange, by means of a specific angular-integrated asymmetry predicted theoretically at next-to-leading order in QCD. For the LHC with nominal energy of 14 TeV and integrated luminosity 100 fb−1, we find that graviton exchange could be discriminated against the scalar one with same mass MR and events rate, up to MR≃3.2TeV.

  3. Perspectives in spintronics: magnetic resonant tunneling, spin-orbit coupling, and GaMnAs

    International Nuclear Information System (INIS)

    Spintronics has attracted wide attention by promising novel functionalities derived from both the electron charge and spin. While branching into new areas and creating new themes over the past years, the principal goals remain the spin and magnetic control of the electrical properties-essentially the I-V characteristics-and vice versa. There are great challenges ahead to meet these goals. One challenge is to find niche applications for ferromagnetic semiconductors, such as GaMnAs. Another is to develop further the science of hybrid ferromagnetic metal/semiconductor heterostructures, as alternatives to all-semiconductor room temperature spintronics. Here we present our representative recent efforts to address such challenges. We show how to make a digital magnetoresistor by combining two magnetic resonant diodes, or how introducing ferromagnetic semiconductors as active regions in resonant tunneling diodes leads to novel effects of digital magnetoresistance and of magnetoelectric current oscillations. We also discuss the phenomenon of tunneling anisotropic magnetoresistance in Fe/GaAs junctions by introducing the concept of the spin-orbit coupling field, as an analog of such fields in all-semiconductor junctions. Finally, we look at fundamental electronic and optical properties of GaMnAs by employing reasonable tight-binding models to study disorder effects.

  4. Rotor Design for High Pressure Magic Angle Spinning Nuclear Magnetic Resonance

    International Nuclear Information System (INIS)

    High pressure magic angle spinning (MAS) nuclear magnetic resonance (NMR) with a sample spinning rate exceeding 2.1 kHz and pressure greater than 165 bar has never been realized. In this work, a new sample cell design is reported, suitable for constructing cells of different sizes. Using a 7.5 mm high pressure MAS rotor as an example, internal pressure as high as 200 bar at a sample spinning rate of 6 kHz is achieved. The new high pressure MAS rotor is re-usable and compatible with most commercial NMR set-ups, exhibiting low 1H and 13C NMR background and offering maximal NMR sensitivity. As an example of its many possible applications, this new capability is applied to determine reaction products associated with the carbonation reaction of a natural mineral, antigorite ((Mg,Fe2+)3Si2O5(OH)4), in contact with liquid water in water-saturated supercritical CO2 (scCO2) at 150 bar and 50 deg C. This mineral is relevant to the deep geologic disposal of CO2, but its iron content results in too many sample spinning sidebands at low spinning rate. Hence, this chemical system is a good case study to demonstrate the utility of the higher sample spinning rates that can be achieved by our new rotor design. We expect this new capability will be useful for exploring solid-state, including interfacial, chemistry at new levels of high-pressure in a wide variety of fields.

  5. Spin-dependent Fano resonance induced by a conducting chiral helimagnet contained in a quasi-one-dimensional electron waveguide

    International Nuclear Information System (INIS)

    Fano resonance appears for conduction through an electron waveguide containing donor impurities. In this work, we consider the thin-film conducting chiral helimagnet (CCH) as the donor impurity in a one-dimensional waveguide model. The transmission and conductance for an arbitrary CCH spiral period are obtained. Due to the spin-spiral coupling, interference between the direct and inter-subband transmission channels gives rise to a spin-dependent Fano resonance effect. The spin-dependent Fano resonance is sensitively dependent on the helicity of the spiral. By tuning the CCH potential well depth and the incident energy, this provides a potential way to detect the spin-spiral period in the CCH.

  6. Spins of resonances in reactions of neutrons with (238)U and (113)Cd. Doctoral thesis; Spins van resonanties in reacties van neutronen met (238)u en (113)cd

    Energy Technology Data Exchange (ETDEWEB)

    Gunsing, F.

    1994-12-31

    In this thesis experiments are described that have lead to the assignments of spins to a large number of resonances in reactions of epithermal neutrons with the nuclei (238)U and (113)Cd. When a neutron is captured by an atomic nucleus, a compound nucleus is formed which is in a highly excited state with an energy of the order of the neutron binding energy. If the kinetic neutron energy is varied around a state of the compound nucleus, one observes a peak in the cross section. This is called a resonance in the reaction. Dependent on the amount or orbital momentum l that the neutron adds to the system, the resonances are indicated with spectroscopic notations as s- and p-waves for l = 0 and 1 respectively. The purpose of this thesis is to determine the spins of such resonances.

  7. Spin-flip Fano–Kondo resonant tunneling through a quantum dot interferometer responded by a rotating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Gao, He; Zhao, Hong-Kang, E-mail: zhaohonk@yahoo.com

    2013-07-15

    The Fano and Kondo cooperated resonant tunneling through a quantum dot interferometer under the perturbation of a rotating magnetic field is investigated theoretically. The spin-polarized current components have been derived generally by employing the Keldysh nonequilibrium Green's function method, through which the charge and spin currents are determined directly. The numerical calculations on spin and charge currents are performed to show the compound features of mesoscopic transport associated with the Kondo, Fano, and Zeeman effects intimately. The induced spin current in the Kondo regime is much different from the one in the non-interacting regime. The spin current is tuned from resonant peak to valley by varying external parameters.

  8. Possibilities for polarized pulsed neutron instrumentation based on the time-of-flight spin-resonance energy filter

    International Nuclear Information System (INIS)

    We present a new approach for dynamic energy filtering at spallation neutron sources, based on the original concept of the Drabkin spin-resonance flipper. The setup takes advantage of the neutron magnetic moment, and consists of a wavelength-selective magnetic resonator and a supermirror polarizer/analyzer system. We are proposing refinements (time dependence and revised magnetic field profiles) to the basic concepts of the setup, making it suitable for time-of-flight experiments at spallation neutron sources. We outline here possibilities for using this spin resonator as the core of new neutron instruments. (orig.)

  9. Ferromagnetic and spin wave resonances in thin layer of expanded austenite phase

    Science.gov (United States)

    Typek, J.; Guskos, N.; Zolnierkiewicz, G.; Berczynski, P.; Guskos, A.; Baranowska, J.; Fryska, S.

    2014-06-01

    Four samples of austenite coatings deposited by reactive magnetron sputtering on silicon substrate at four different temperatures and pressures were investigated by ferromagnetic resonance (FMR) method at room temperature. The expanded austenite phase S ( γ N ) layers with thickness in the 160-273 nm range and concentration of magnetic atoms: 72 % Fe, 18 % Cr and 10 % Ni, were obtained. The coatings with nanometric size grains were strongly textured and grown mostly in [100] direction, perpendicular to the sample surface. Intense FMR spectra were recorded at various angles between the static magnetic field direction and the sample surface. A strong magnetic anisotropy of the main uniform FMR mode was observed and the effective magnetization 4 πM eff determined. Spin wave resonance (SWR) modes were observed in all investigated samples in out-of-plane geometry of the magnetic field. The resonance fields of SWR modes in our samples varied linearly with the spin wave mode number. The value of the effective magnon stiffness constant was determined assuming a parabolic shape of the magnetization variation across the sample thickness.

  10. Spin and Parity Assignment of Neutron Resonances using Gamma-ray Multiplicity

    International Nuclear Information System (INIS)

    Decay gamma rays following neutron capture on various isotopes are collected by the Detector for Advanced Neutron Capture Experiments (DANCE) array, which is located at flight path 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation (160 detectors) and close packing of the detector array enable gamma-ray multiplicity measurements. The calorimetric properties of the DANCE array coupled with the neutron time-of-flight technique enables one to gate on a specific resonance of a given isotope in the time-of-flight spectrum and obtain the summed energy spectrum for that isotope. The singles gamma-ray spectrum for each multiplicity can be separated by their DANCE cluster multiplicity. The multiplicity distribution contains the signatures of spin and parity of the capture state. Under suitable circumstances where the difference between spins of the initial (capture) and final (ground) state is large enough, the signatures in the multiplicity distribution can be used in improving the spin assignment of the initial state. The spin assignment is applied with varying degree of success to difference isotopes and description of this application for 95Mo, 151,153Eu, and 155,157Gd is reviewed briefly.

  11. The fate of allogenic radiation sterilized bone grafts controlled by the electron spin resonance spectrometry

    International Nuclear Information System (INIS)

    The normal fate of bone grafts is their resorption and substitution by the own host's bone tissue. This phenomenon described as creeping substitution process was controlled using biopsies from the grafted region in allogenic experimental system. Electron spin resonance (ESR) spectrometry was used for independent evaluation of resorption and substitution processes. The measurements were based on the process of induction in the hydroxyapatite (HA) crystals of bone mineral of stable paramagnetic centers which can be detected by ESR spectrometry. The loss of total amount of spins connected with the paramagnetic centers expressed in percent describes the kinetics of resorption. The changes in the concentration of spins due to the ''dilution'' of spins implanted with the graft by the nonirradiated ingrowing host's own bone describe the kinetics of the substitution process. Allogenic bone of calvaria was grafted orthotopically into rabbits after lyophilization and radiation sterilization with a dose of 3.5 Mrads. The process of graft's rebuilding was evaluated using the described ESR method. The application of the described technique in the human clinic is possible. (author)

  12. Spin-torque resonant expulsion of the vortex core for an efficient radiofrequency detection scheme.

    Science.gov (United States)

    Jenkins, A S; Lebrun, R; Grimaldi, E; Tsunegi, S; Bortolotti, P; Kubota, H; Yakushiji, K; Fukushima, A; de Loubens, G; Klein, O; Yuasa, S; Cros, V

    2016-04-01

    It has been proposed that high-frequency detectors based on the so-called spin-torque diode effect in spin transfer oscillators could eventually replace conventional Schottky diodes due to their nanoscale size, frequency tunability and large output sensitivity. Although a promising candidate for information and communications technology applications, the output voltage generated from this effect has still to be improved and, more pertinently, reduces drastically with decreasing radiofrequency (RF) current. Here we present a scheme for a new type of spintronics-based high-frequency detector based on the expulsion of the vortex core in a magnetic tunnel junction (MTJ). The resonant expulsion of the core leads to a large and sharp change in resistance associated with the difference in magnetoresistance between the vortex ground state and the final C-state configuration. Interestingly, this reversible effect is independent of the incoming RF current amplitude, offering a fast real-time RF threshold detector. PMID:26727200

  13. Spin-torque diode radio-frequency detector with voltage tuned resonance

    Energy Technology Data Exchange (ETDEWEB)

    Skowroński, Witold, E-mail: skowron@agh.edu.pl; Frankowski, Marek; Stobiecki, Tomasz [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Wrona, Jerzy [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Singulus Technologies, Kahl am Main 63796 (Germany); Ogrodnik, Piotr [Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw (Poland); AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Barnaś, Józef [Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań (Poland); Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań (Poland)

    2014-08-18

    We report on a voltage-tunable radio-frequency (RF) detector based on a magnetic tunnel junction (MTJ). The spin-torque diode effect is used to excite and/or detect RF oscillations in the magnetic free layer of the MTJ. In order to reduce the overall in-plane magnetic anisotropy of the free layer, we take advantage of the perpendicular magnetic anisotropy at the interface between ferromagnetic and insulating layers. The applied bias voltage is shown to have a significant influence on the magnetic anisotropy, and thus on the resonance frequency of the device. This influence also depends on the voltage polarity. The obtained results are accounted for in terms of the interplay of spin-transfer-torque and voltage-controlled magnetic anisotropy effects.

  14. Effect of ionising radiation on potassium pentacyanonitrosyl ruthenate(II): an electron spin resonance study

    Energy Technology Data Exchange (ETDEWEB)

    Vugman, Ney V.; Pinhal, Nelson M.; Amorim, Helio S. de [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Fisica. Dept. de Fisica dos Solidos. E-mail: ney@if.ufrj.br; Santos, Cristina M.P. dos; Faria, Roberto B. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica. Dept. de Quimica Inorganica

    2000-06-01

    Amorphous potassium pentacyanonitrosyl ruthenate (II) was synthesized and characterized by UV, IR, X-ray diffraction and thermogravimetric analysis. Electron Spin Resonance spectroscopy reveals the presence of paramagnetic ruthenate (i) complexes and NO{sub 2} radicals in the X-irradiated diamagnetic salt. Spin-Hamiltonian parameters of the [Ru (CN){sub 5} N O]{sup 3-} complex (g=2.0064, A ({sup 14} N) = 60.7 MHz, g = 1.999, A ({sup 14} N) = 77.3 MHz) support an electron capture in a {pi}{sup *} molecular orbital of the nitrosyl group mixed with d{sub xz} and d{sub yz} ruthenium orbitals as recently predicted by theoretical calculations. Silver ions, present as impurities, are reduced to Ag(o) by X-irradiation and coordinate to four magnetically equivalent nitrogens in a distorted site, giving to a well resolved anisotropic ESR powder spectrum. (author)

  15. Quantum Computation Based on Magic-Angle-Spinning Solid State Nuclear Magnetic Resonance Spectroscopy

    CERN Document Server

    Ding, S; Ye, C; Zhan, M S; Zhu, X; Gao, K; Sun, X; Mao, X A; Liu, M; Ding, Shangwu; Dowell, Charles A. Mc; Ye, Chaohui; Zhan, Mingsheng; Zhu, Xiwen; Gao, Kelin; Sun, Xianping; Mao, Xi-An; Liu, Maili

    2001-01-01

    Magic-angle spinning (MAS) solid state nuclear magnetic resonance (NMR) spectroscopy is shown to be a promising technique for implementing quantum computing. The theory underlying the principles of quantum computing with nuclear spin systems undergoing MAS is formulated in the framework of formalized quantum Floquet theory. The procedures for realizing state labeling, state transformation and coherence selection in Floquet space are given. It suggests that by this method, the largest number of qubits can easily surpass that achievable with other techniques. Unlike other modalities proposed for quantum computing, this method enables one to adjust the dimension of the working state space, meaning the number of qubits can be readily varied. The universality of quantum computing in Floquet space with solid state NMR is discussed and a demonstrative experimental implementation of Grover's search is given.

  16. Detection of Nitric Oxide by Electron Paramagnetic Resonance Spectroscopy: Spin-Trapping with Iron-Dithiocarbamates.

    Science.gov (United States)

    Maia, Luisa B; Moura, José J G

    2016-01-01

    Electron paramagnetic resonance (EPR) spectroscopy is the ideal methodology to identify radicals (detection and characterization of molecular structure) and to study their kinetics, in both simple and complex biological systems. The very low concentration and short life-time of NO and of many other radicals do not favor its direct detection and spin-traps are needed to produce a new and persistent radical that can be subsequently detected by EPR spectroscopy.In this chapter, we present the basic concepts of EPR spectroscopy and of some spin-trapping methodologies to study NO. The "strengths and weaknesses" of iron-dithiocarbamates utilization, the NO traps of choice for the authors, are thoroughly discussed and a detailed description of the method to quantify the NO formation by molybdoenzymes is provided. PMID:27094413

  17. Theoretical approaches to control spin dynamics in solid-state nuclear magnetic resonance

    Indian Academy of Sciences (India)

    Eugene Stephane Mananga

    2015-12-01

    This article reviews theoretical approaches for controlling spin dynamics in solid-state nuclear magnetic resonance. We present fundamental theories in the history of NMR, namely, the average Hamiltonian and Floquet theories. We also discuss emerging theories such as the Fer and Floquet-Magnus expansions. These theories allow one to solve the time-dependent Schrodinger equation, which is still the central problem in spin dynamics of solid-state NMR. Examples from the literature that highlight several applications of these theories are presented, and particular attention is paid to numerical integrators and propagator operators. The problem of time propagation calculated with Chebychev expansion and the future development of numerical directions with the Cayley transformation are considered. The bibliography includes 190 references.

  18. Spin-torque resonant expulsion of the vortex core for an efficient radiofrequency detection scheme

    Science.gov (United States)

    Jenkins, A. S.; Lebrun, R.; Grimaldi, E.; Tsunegi, S.; Bortolotti, P.; Kubota, H.; Yakushiji, K.; Fukushima, A.; de Loubens, G.; Klein, O.; Yuasa, S.; Cros, V.

    2016-04-01

    It has been proposed that high-frequency detectors based on the so-called spin-torque diode effect in spin transfer oscillators could eventually replace conventional Schottky diodes due to their nanoscale size, frequency tunability and large output sensitivity. Although a promising candidate for information and communications technology applications, the output voltage generated from this effect has still to be improved and, more pertinently, reduces drastically with decreasing radiofrequency (RF) current. Here we present a scheme for a new type of spintronics-based high-frequency detector based on the expulsion of the vortex core in a magnetic tunnel junction (MTJ). The resonant expulsion of the core leads to a large and sharp change in resistance associated with the difference in magnetoresistance between the vortex ground state and the final C-state configuration. Interestingly, this reversible effect is independent of the incoming RF current amplitude, offering a fast real-time RF threshold detector.

  19. Field and frequency modulated sub-THz electron spin resonance spectrometer

    Science.gov (United States)

    Caspers, Christian; da Silva, Pedro Freire; Soundararajan, Murari; Haider, M. Ali; Ansermet, Jean-Philippe

    2016-05-01

    260-GHz radiation is used for a quasi-optical electron spin resonance (ESR) spectrometer which features both field and frequency modulation. Free space propagation is used to implement Martin-Puplett interferometry with quasi-optical isolation, mirror beam focusing, and electronic polarization control. Computer-aided design and polarization pathway simulation lead to the design of a compact interferometer, featuring lateral dimensions less than a foot and high mechanical stability, with all components rated for power levels of several Watts suitable for gyrotron radiation. Benchmark results were obtained with ESR standards (BDPA, DPPH) using field modulation. Original high-field ESR of 4f electrons in Sm3+-doped Ceria was detected using frequency modulation. Distinct combinations of field and modulation frequency reach a signal-to-noise ratio of 35 dB in spectra of BDPA, corresponding to a detection limit of about 1014 spins.

  20. Spin Structure Functions of the Deuteron Measured with CLAS in and above the Resonance Region

    Energy Technology Data Exchange (ETDEWEB)

    Kahanawita Dharmawardane

    2004-05-01

    Spin structure functions of the nucleon in the region of large x and small to moderate Q{sup 2} continue to be of high current interest. The first moment of the spin structure function g{sub 1}, {Gamma}{sub 1}, goes through a rapid transition from the photon point (Q{sup 2}=0), where it is constrained by the Gerasimov-Drell-Hearn sum rule, to the deep inelastic limit where it is sensitive to the nucleon spin fraction carried by quarks. The interesting behavior in the transition region is dominated by baryon resonance excitations. We concluded an experiment to measure these observables for deuterium as part of the ''EG1'' run group in Jefferson Lab's Hall B. We used a highly polarized electron beam with energies from 1.6 GeV to 5.7 GeV and a cryogenic polarized ND{sub 3} target together with the CEBAF Large Acceptance Spectrometer (CLAS) to accumulate over 11 billion events. In this thesis, we present results for the spin structure function g{sub 1}{sup d} (x,Q{sup 2}), as well as its first moment, {Gamma}{sub 1}{sup d}(Q{sup 2}) in and above the resonance region over a Q{sup 2} range from 0.05 to 5 Gev{sup 2}, based on the data taken with beam energies of 1.6 and 5.7 GeV. We also extract the behavior of A{sub 1}{sup d}(x) at large x. Our data are consistent with the Hyperfine-perturbed quark model calculation which predicts that A{sub 1}{sup d} (x {yields} 1) {yields} 1. We also see evidence for duality in g{sub 1}{sup d} (x, Q{sup 2}) at Q{sup 2} > GeV{sup 2}.

  1. Magnetic properties and electron spin resonance of Ecuadorian obsidians. Application to provenance research of archeological samples

    International Nuclear Information System (INIS)

    Obsidians from major Ecuadorian sources were analyzed by SQUID magnetometry and electron spin resonance (ESR). The association of these two techniques permits to differentiate obsidians from the sources of Cotopaxi volcano and from the Quiscatola and Mullumica-Callejones sources of the Chacana caldera, taking into account various parameters arising from the M vs. H cycles and the X-band ESR spectra. The analysis of 27 archeological samples coming from the prehispanic site of La Mana allowed us to infer that most of them come from the Mullumica-Callejones source

  2. Constraining spin-one color-octet resonances using CDF and ATLAS data

    Energy Technology Data Exchange (ETDEWEB)

    Zerwekh, Alfonso R. [Universidad Austral de Chile and Centro Cientifico-Tecnologico de Valparaiso, Instituto de Fisica, Facultad de Ciencias, Valdivia (Chile)

    2010-12-15

    In this paper, we study the production of spin-one color-octet resonances (colorons) at hadron colliders in a model independent way. We use dijets data measured by CDF (at {radical}(s)=1.96 TeV and L=1.13 pb{sup -1}) and ATLAS (at {radical}(s)=7 TeV and L=315 nb{sup -1}) collaborations at the Tevatron and the LHC respectively to impose limits on the coupling of colorons to fermions. We show that CDF data still produce the more stringent limits on the coloron coupling constant. (orig.)

  3. Electron spin resonance (ESR) studies on irradiated cocoa beans and niger seeds

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) spectra of irradiated (10kGy) and unirradiated cocoa beans and niger seeds have been compared. Unirradiated cocoa beans failed to give any ESR signal, whereas after irradiation (10kGy) an ESR signal at g = 2.0042 was observed. However, ESR signals are given by both irradiated and unirradiated niger seeds. The intensity of signal was found to be dose-dependent up to 10kGy for both seeds. The signals were stable up to 180 days in both cases. The results indicate the possibility of using ESR for distinguishing between irradiated and unirradiated cocoa beans but not for niger seeds

  4. Use of thermoluminescence and electron spin resonance for identification of irradiated vital wheat gluten

    International Nuclear Information System (INIS)

    The effects of ionizing gamma-radiation on wheat gluten's chemical properties and induced phenomena are investigated by thermoluminescence and electron spin resonance. The vital wheat gluten can be considered as a whole sample of protein-containing foodstuffs. The water, protein and starch content and water-absorbing capacity have been measured. It was found that some chemical parameters are changed due to irradiation, and the identification of irradiated samples as function of both radiation dose and storage time is done by the methods used. (author)

  5. The electron spin resonance study of heavily nitrogen doped 6H SiC crystals

    Czech Academy of Sciences Publication Activity Database

    Savchenko, Dariia

    2015-01-01

    Roč. 117, č. 4 (2015), "045708-1"-"045708-6". ISSN 0021-8979 R&D Projects: GA ČR GP13-06697P; GA MŠk(CZ) LM2011029 Grant ostatní: SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 Keywords : electron spin resonance * conduction electrons * 6H SiC * insulator-metal transition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.183, year: 2014

  6. Multipurpose High Frequency Electron Spin Resonance Spectrometer for Condensed Matter Research

    OpenAIRE

    Nagy, Kalman L; Quintavalle, Dario; Feher, Titusz; Janossy, Andras

    2009-01-01

    We describe a quasi-optical multifrequency ESR spectrometer operating in the 75-225 GHz range and optimized at 210 GHz for general use in condensed matter physics, chemistry and biology. The quasi-optical bridge detects the change of mm wave polarization at the ESR. A controllable reference arm maintains a mm wave bias at the detector. The attained sensitivity of 2x10^10 spin/G/(Hz)1/2, measured on a dilute Mn:MgO sample in a non-resonant probe head at 222.4 GHz and 300 K, is comparable to co...

  7. Ferromagnetic resonance investigation of the residual coupling in spin-valve systems

    Science.gov (United States)

    Rodríguez-Suárez, R. L.; Rezende, S. M.; Azevedo, A.

    2005-06-01

    The ferromagnetic resonance (FMR) technique has been used to investigate the properties of spin-valve systems. We derive the FMR dispersion relation taking into account the competition that appears between the direct exchange bias coupling and the indirect interlayer coupling. For uncoupled ferromagnetic (FM) layers, the system exhibits a dispersion relation corresponding to two independent systems: a single FM layer (free layer) and an exchange-coupled bilayer (reference/antiferromagnetic layers). In the interlayer coupled regime a unidirectional anisotropy is induced in the free layer and the FMR field is overall downshifted. Both features are observed experimentally and the results are compared with the model.

  8. dc effect in ferromagnetic resonance: Evidence of the spin-pumping effect?

    Science.gov (United States)

    Azevedo, A.; Vilela Leão, L. H.; Rodriguez-Suarez, R. L.; Oliveira, A. B.; Rezende, S. M.

    2005-05-01

    Direct current voltage appears across and in plane of a ferromagnetic multilayer experiencing ferromagnetic resonance. We have investigated the dc voltage simultaneously generated with the excitation of the uniform mode of magnetization precession in ferromagnetic/normal-metal/ferromagnetic trilayers with different spacer-layer materials. The generated voltage strongly depends on the chemical nature and the thickness of the normal-metal spacer as well as on the microwave incident power. This dc voltage might be correlated with the spin-pumping effect recently predicted.

  9. An Electron Spin Resonance Study of Stearic Acid Interactions in Model Wheat Starch and Gluten Systems

    OpenAIRE

    Pearce, L. E.; Davis, E. A.; Gordon, J.; Miller, W. G.

    1987-01-01

    Electron spin resonance (ESR) was used to examine interactions of 16- Doxyl stearic acid in wheat starch-water (starch:water "'1: 1), vital wheat gluten-water and glut en-starch-water model systems, Immobilization of the 16-Doxyl stearic acid, shown by broadIine ESR powder patterns , occurred in wheat starch model systems. In contrast to the starch systems, 16-Doxylstearic acid in gluten-water systems did not display broad line powder patterns. Broadened 3- line ESR spectra were recorded for ...

  10. Electron spin resonance measurements in CoFe2O4 free rotor nanoparticles

    International Nuclear Information System (INIS)

    Recently, a new magnetic behaviour has been observed in the nanoparticles that rotate freely in response to an applied static magnetic field (i.e., 'free rotor behaviour') after conditioning the material in a cycling magnetic field. On the other hand, in an electron spin resonance (ESR) experiment where microwave power excites a free magnetic moment without any anisotropy a zero-field-absorption in the spectrum is predicted at all temperatures and independent of the microwave frequency. In this contribution we present ESR measurements on CoFe2O4 nanoparticles in a polymer matrix with free-rotor behaviour, and the zero-field-absorption results will be discussed

  11. Electron spin resonance (ESR) in multiferroic TbMnO3

    International Nuclear Information System (INIS)

    We report temperature dependent X-Band (ν∼9.4GHz) electron spin resonance (ESR) measurement in a single crystal of TbMnO3. A single Lorentzian ESR line with an isotropic g∼ 1.96 was observed for T>=120K up to 600K. The ESR signal is attributed to the Mn3+ ions in a insulator environment. For the three crystallographic axes the temperature dependence ESR linewidth shows a strong broadening as the temperature decreases due to the presence of short range magnetic correlations

  12. Solid state nuclear magnetic resonance: investigating the spins of nuclear related materials

    International Nuclear Information System (INIS)

    The author reviews his successive research works: his research thesis work on the Multiple Quantum Magic Angle Spinning (MQMAS) which is a quadric-polar nucleus multi-quanta correlation spectroscopy method, the modelling of NMR spectra of disordered materials, the application to materials of interest for the nuclear industry (notably the glasses used for nuclear waste containment). He presents the various research projects in which he is involved: storing glasses, nuclear magnetic resonance in paramagnetism, solid hydrogen storing matrices, methodological and instrument developments in high magnetic field and high resolution solid NMR, long range distance measurement by solid state Tritium NMR (observing the structure and dynamics of biological complex systems at work)

  13. Study by electron spin resonance of the free radicals created under irradiation in glycine

    International Nuclear Information System (INIS)

    The free radicals created by different radiations in glycine are measured by electron spin resonance and their number is evaluated in function of the absorbed dose. This number decreases when the LET of the radiations increases ; in other words,high LET radiations gives less radiochemical effects; in contrary with the fact that high LET radiations creates more damage in biological materials. The decreasing with time of the number of free radicals and the speed of this decrease is a function of temperature; by the study of the kinetics of this decrease, an attempt has been made to prove the presence of three radicals. (authors)

  14. Electron spin resonance dosimetry of teeth of Goiania radiation accident victims

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) spectroscopy is used to assess absorbed doses of six teeth belonging to victims of the highly irradiated group of Goiania accident. The influence of the broad background signal at g=2.0040 as well as of the unstable fraction of CO-2 radicals was taken into account in dose estimates. Three victims teeth showed absorbed doses comparable to those estimated by chromosomal analysis. For the other three teeth, the doses were higher by a factor of 1.3, 1.8 and 2.2

  15. Indirect identification of irradiated foodstuff by electron spin resonance measurements at synthetic packaging materials

    International Nuclear Information System (INIS)

    Goal of this work was to proof, whether an indirect identification of irradiated foodstuffs can be performed by electron spin resonance measurements on specific radicals built in synthetic packaging materials like polyethylene, polypropylene or polystyrene. For e.s.r. measurements two different spectrometers were used: a newly designed routine spectrometer and a research instrument. All measurements were carried out at ambient temperature. The following synthetic materials were studied: Polyethylene, polypropylene, polystyrene, polyethyleneterephtalate and acrylnitril-butadiene-styrene-copolymere. The first three mentioned materials are commonly used in food industry. Investigations were performed with standard samples (granulate, balls) of the pure polymere and additionally with commercially used packaging materials. (orig./MG)

  16. Retrospective Dosimetry: Dose Analysis From Tooth Enamel Using Electron Spin Resonance (ESR)

    International Nuclear Information System (INIS)

    The radiation dose should be accurately measured in order to relate its effect to the cells. The assessment of dose usually performed using biological dosimetry techniques. However, the reduction of lymphocytes (white blood cells) after the time period results in inaccuracy of dose measurement. An alternative method used is the application of Electron Spin Resonance (ESR) using tooth enamel. In this study, tooth enamels were evaluated and used to measure the individual absorbed dose from the background. The basic tooth features that would affect dose measurement were discussed. The results show this technique is capable and effective for retrospective dose measurement and useful for the study of radiation effect to human. (author)

  17. Determination of the feasibility of directly dating quartz by electron spin resonance

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) analyses have been made of natural quartz samples ranging in age from 100 ka to 1.4 Ga. Signal intensities of two ESR centres that can be associated with Schottky-Frenkel (SF) defects are significantly correlated with age. These defects are thought to accumulate naturally as a result of elastic collisions in the quartz lattice initiated by the recoil of alpha-emitting nuclides present in the impurities. Preliminary indications are that recoil-induced SF defects can be significantly more abundant than original SF defects in samples older than several million years. These considerations provide the theoretical basis for a long-ranging quartz geochronometer

  18. Mercury's capture into the 3/2 spin-orbit resonance including the effect of core-mantle friction

    Science.gov (United States)

    Correia, Alexandre C. M.; Laskar, Jacques

    2009-05-01

    The rotation of Mercury is presently captured in a 3/2 spin-orbit resonance with the orbital mean motion. The capture mechanism is well understood as the result of tidal interactions with the Sun combined with planetary perturbations [Goldreich, P., Peale, S., 1966. Astron. J. 71, 425-438; Correia, A.C.M., Laskar, J., 2004. Nature 429, 848-850]. However, it is now almost certain that Mercury has a liquid core [Margot, J.L., Peale, S.J., Jurgens, R.F., Slade, M.A., Holin, I.V., 2007. Science 316, 710-714] which should induce a contribution of viscous friction at the core-mantle boundary to the spin evolution. According to Peale and Boss [Peale, S.J., Boss, A.P., 1977. J. Geophys. Res. 82, 743-749] this last effect greatly increases the chances of capture in all spin-orbit resonances, being 100% for the 2/1 resonance, and thus preventing the planet from evolving to the presently observed configuration. Here we show that for a given resonance, as the chaotic evolution of Mercury's orbit can drive its eccentricity to very low values during the planet's history, any previous capture can be destabilized whenever the eccentricity becomes lower than a critical value. In our numerical integrations of 1000 orbits of Mercury over 4 Gyr, the spin ends 99.8% of the time captured in a spin-orbit resonance, in particular in one of the following three configurations: 5/2 (22%), 2/1 (32%) and 3/2 (26%). Although the present 3/2 spin-orbit resonance is not the most probable outcome, we also show that the capture probability in this resonance can be increased up to 55% or 73%, if the eccentricity of Mercury in the past has descended below the critical values 0.025 or 0.005, respectively.

  19. Enhancing ferromagnetic resonance absorption for very thin insulating magnetic films with spin plasmonics

    International Nuclear Information System (INIS)

    We consider enhancing the ferromagnetic resonance (FMR) absorption of very thin insulating magnetic films by placing it on top of a dielectric. We find that the signal is enhanced by at least an order of magnitude due to a new nonreciprocal interface resonance that is a mixture of the magnetic surface plasmon mode and a wave guide mode. This resonance occurs over a wide range of thicknesses of the dielectric that is still much less than the wavelength and is made possible by the negative magnetic susceptibility of the magnetic layer. The line width of absorption is reduced by an order of magnitude less than the Gilbert damping parameter. At some frequency, the group velocity of this resonance is negative. Experimentally, very thin yttrium iron garnet (YIG) films are grown on a Gadolinium Gallium Garnet (GGG) substrate which can be considered the dielectric. Our model applies to experiments performed in the YIG/GGG system. Indeed, our picture resolves the disagreement on the magnitude of the spin diffusion lengths obtained with the FMR and the Brillouin scattering techniques. It also provides for a way to make new adaptive thin film miniaturized photonic nonreciprocal devices with low loss

  20. Enhancing ferromagnetic resonance absorption for very thin insulating magnetic films with spin plasmonics

    Energy Technology Data Exchange (ETDEWEB)

    Chui, S. T. [Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)

    2015-05-14

    We consider enhancing the ferromagnetic resonance (FMR) absorption of very thin insulating magnetic films by placing it on top of a dielectric. We find that the signal is enhanced by at least an order of magnitude due to a new nonreciprocal interface resonance that is a mixture of the magnetic surface plasmon mode and a wave guide mode. This resonance occurs over a wide range of thicknesses of the dielectric that is still much less than the wavelength and is made possible by the negative magnetic susceptibility of the magnetic layer. The line width of absorption is reduced by an order of magnitude less than the Gilbert damping parameter. At some frequency, the group velocity of this resonance is negative. Experimentally, very thin yttrium iron garnet (YIG) films are grown on a Gadolinium Gallium Garnet (GGG) substrate which can be considered the dielectric. Our model applies to experiments performed in the YIG/GGG system. Indeed, our picture resolves the disagreement on the magnitude of the spin diffusion lengths obtained with the FMR and the Brillouin scattering techniques. It also provides for a way to make new adaptive thin film miniaturized photonic nonreciprocal devices with low loss.

  1. Tuning of the spin distribution between ligand- and metal-based spin: electron paramagnetic resonance of mixed-ligand molybdenum tris(dithiolene) complex anions.

    Science.gov (United States)

    Fekl, Ulrich; Sarkar, Biprajit; Kaim, Wolfgang; Zimmer-De Iuliis, Marco; Nguyen, Neilson

    2011-09-19

    Electron paramagnetic resonance spectra of homoleptic and mixed-ligand molybdenum tris(dithiolene) complex anions [Mo(tfd)(m)(bdt)(n)](-) (n + m = 3; bdt = S(2)C(6)H(4); tfd = S(2)C(2)(CF(3))(2)) reveal that the spin density has mixed metal-ligand character with more ligand-based spin for [Mo(tfd)(3)](-) and a higher degree of metal-based spin for [Mo(bdt)(3)](-): the magnitude of the isotropic (95,97)Mo hyperfine interaction increases continuously, by a factor of 2.5, on going from the former to the latter. The mixed complexes fall in between, and the metal character of the spin increases with the bdt content. The experiments were corroborated by density functional theory computations, which reproduce this steady increase in metal-based character. PMID:21853970

  2. Air oxidation of the kerogen/asphaltene vanadyl porphyrins: an electron spin resonance study

    Directory of Open Access Journals (Sweden)

    MIRJANA S. PAVLOVIC

    2000-02-01

    Full Text Available The thermal behavior of vanadyl porphyrins was studied by electron spin resonance during heating of kerogens, isolated from the La Luna (Venezuela and Serpiano (Switzerland bituminous rocks, at 25°C for 1 to 20 days in the presence of air. During the thermal treatment of the kerogens, the vanadyl porphyrins resonance signals decrease monotonically and become quite small after 6 days of heating. Concomitantly, new vanadyl signals appear and, at longer heating times, dominate the spectrum. It is suggested that the secondary vanadyl species must have been formed from vanadyl porphyrins. Similar conversions of vanadyl porphyrins are observed under the same experimental conditions for asphaltenes extracted from the La Luna and Serpiano rocks, and floating asphalt from the Dead Sea (Israel. A comparison of the spin-Hamiltonian parameters for vanadyl porphyrins and the vanadyl compounds obtained during pyrolysis of the kerogens/asphaltenes suggests that the latter are of a non-porphyrin type. For comparison a study was conducted on Western Kentucky No. 9 coal enriched with vanadium (>>400 ppm from six mines. All the coal samples show only the presence of predominant by non-porphyrin vanadyl compounds, similar to those generated through laboratory heating of the kerogens/asphaltenes in air. In addition, some samples also contain a minor amount of vanadyl porphyrins.

  3. Observations of thermally excited ferromagnetic resonance on spin torque oscillators having a perpendicularly magnetized free layer

    Energy Technology Data Exchange (ETDEWEB)

    Tamaru, S., E-mail: shingo.tamaru@aist.go.jp; Kubota, H.; Yakushiji, K.; Konoto, M.; Nozaki, T.; Fukushima, A.; Imamura, H.; Taniguchi, T.; Arai, H.; Tsunegi, S.; Yuasa, S. [Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Suzuki, Y. [Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan)

    2014-05-07

    Measurements of thermally excited ferromagnetic resonance were performed on spin torque oscillators having a perpendicularly magnetized free layer and in-plane magnetized reference layer (abbreviated as PMF-STO in the following) for the purpose of obtaining magnetic properties in the PMF-STO structure. The measured spectra clearly showed a large main peak and multiple smaller peaks on the high frequency side. A Lorentzian fit on the main peak yielded Gilbert damping factor of 0.0041. The observed peaks moved in proportion to the out-of-plane bias field. From the slope of the main peak frequency as a function of the bias field, Lande g factor was estimated to be about 2.13. The mode intervals showed a clear dependence on the diameter of the PMF-STOs, i.e., intervals are larger for a smaller diameter. These results suggest that the observed peaks should correspond to eigenmodes of lateral spin wave resonance in the perpendicularly magnetized free layer.

  4. DETERMINATION OF ACRYLAMIDE IN RAT SERUM AND SCIATIC NERVE BY GAS CHROMATOGRAPHY-ELECTRON-CAPTURE DETECTION

    Science.gov (United States)

    A modified method for the derivatization and analysis of acrylamide as 2-bromopropenamide by gas chromatography/electron capture detection was validated in serum and sciatic nerve from rats. he method was accurate and precise over the concentration range of 2240 to 74700 ppm (w/v...

  5. Compton scattering in strong magnetic fields: Spin-dependent influences at the cyclotron resonance

    Science.gov (United States)

    Gonthier, Peter L.; Baring, Matthew G.; Eiles, Matthew T.; Wadiasingh, Zorawar; Taylor, Caitlin A.; Fitch, Catherine J.

    2014-08-01

    The quantum electrodynamical (QED) process of Compton scattering in strong magnetic fields is commonly invoked in atmospheric and inner magnetospheric models of x-ray and soft gamma-ray emission in high-field pulsars and magnetars. A major influence of the field is to introduce resonances at the cyclotron frequency and its harmonics, where the incoming photon accesses thresholds for the creation of virtual electrons or positrons in intermediate states with excited Landau levels. At these resonances, the effective cross section typically exceeds the classical Thomson value by over 2 orders of magnitude. Near and above the quantum critical magnetic field of 44.13 TeraGauss, relativistic corrections must be incorporated when computing this cross section. This profound enhancement underpins the anticipation that resonant Compton scattering is a very efficient process in the environs of highly magnetized neutron stars. This paper presents formalism for the QED magnetic Compton differential cross section valid for both subcritical and supercritical fields, yet restricted to scattered photons that are below pair creation threshold. Calculations are developed for the particular case of photons initially propagating along the field, and in the limit of zero vacuum dispersion, mathematically simple specializations that are germane to interactions involving relativistic electrons frequently found in neutron star magnetospheres. This exposition of relativistic, quantum, magnetic Compton cross sections treats electron spin dependence fully, since this is a critical feature for describing the finite decay lifetimes of the intermediate states. Such lifetimes are introduced to truncate the resonant cyclotronic divergences via standard Lorentz profiles. The formalism employs both the traditional Johnson and Lippmann (JL) wave functions and the Sokolov and Ternov (ST) electron eigenfunctions of the magnetic Dirac equation. The ST states are formally correct for self

  6. Continuous dynamical decoupling of a single diamond nitrogen-vacancy center spin with a mechanical resonator

    Science.gov (United States)

    MacQuarrie, E. R.; Gosavi, T. A.; Bhave, S. A.; Fuchs, G. D.

    2015-12-01

    Inhomogeneous dephasing from uncontrolled environmental noise can limit the coherence of a quantum sensor or qubit. For solid-state spin qubits such as the nitrogen-vacancy (NV) center in diamond, a dominant source of environmental noise is magnetic field fluctuations due to nearby paramagnetic impurities and instabilities in a magnetic bias field. In this work, we use ac stress generated by a diamond mechanical resonator to engineer a dressed spin basis in which a single NV center qubit is less sensitive to its magnetic environment. For a qubit in the thermally isolated subspace of this protected basis, we prolong the dephasing time T2* from 2.7 ±0.1 to 15 ±1 μ s by dressing with a Ω /2 π =581 ±2 kHz mechanical Rabi field. Furthermore, we develop a model that quantitatively predicts the relationship between Ω and T2* in the dressed basis. Our model suggests that a combination of magnetic field fluctuations and hyperfine coupling to nearby nuclear spins limits the protected coherence time over the range of Ω accessed here. We show that amplitude noise in Ω will dominate the dephasing for larger driving fields.

  7. Accelerated 2D magnetic resonance spectroscopy of single spins using matrix completion

    Science.gov (United States)

    Scheuer, Jochen; Stark, Alexander; Kost, Matthias; Plenio, Martin B.; Naydenov, Boris; Jelezko, Fedor

    2015-12-01

    Two dimensional nuclear magnetic resonance (NMR) spectroscopy is one of the major tools for analysing the chemical structure of organic molecules and proteins. Despite its power, this technique requires long measurement times, which, particularly in the recently emerging diamond based single molecule NMR, limits its application to stable samples. Here we demonstrate a method which allows to obtain the spectrum by collecting only a small fraction of the experimental data. Our method is based on matrix completion which can recover the full spectral information from randomly sampled data points. We confirm experimentally the applicability of this technique by performing two dimensional electron spin echo envelope modulation (ESEEM) experiments on a two spin system consisting of a single nitrogen vacancy (NV) centre in diamond coupled to a single 13C nuclear spin. The signal to noise ratio of the recovered 2D spectrum is compared to the Fourier transform of randomly subsampled data, where we observe a strong suppression of the noise when the matrix completion algorithm is applied. We show that the peaks in the spectrum can be obtained with only 10% of the total number of the data points. We believe that our results reported here can find an application in all types of two dimensional spectroscopy, as long as the measured matrices have a low rank.

  8. Optical and electron spin resonance spectroscopy of Ti3+-doped yttrium and gadolinium aluminoborates

    International Nuclear Information System (INIS)

    Single crystals of Ti3+-doped aluminoborates YAl3(BO3)4 (YAB) and GdAl3(BO3)4 (GAB) have been grown by the top-seeded solution growth technique, and the optical absorption, photoluminescence and electron spin resonance (ESR) properties of Ti3+ dopants measured at low temperature. The optical absorption spectrum of Ti3+ comprises two broad bands with peaks at 514 and 576 nm in YAB and at 520 and 586 nm in GAB. The energy separation of the two bands in each crystal is due to the static Jahn-Teller splitting of the excited 2E state of the Ti3+ ions. Photoluminescence from excited Ti3+ ions occurs as a broad band in the near-infrared region with a peak at λ = 747 nm in YAB and 754 nm in GAB when measured at 14 K. Both absorption and photoluminescence spectra are strongly polarized. The spin Hamiltonian parameters for Ti3+ ions substituting at trigonally symmetric Al3+ sites in YAB have been determined from the orientation dependence of the ESR spectra. The measured shifts in the components of the g-tensor from the free electron g-value of 2.0023 are interpreted in terms of the mixing of the higher component of the 2T2 ground states and of the 2E excited state into the lowest 2T2 ground state by spin-orbit interaction. (author)

  9. Nuclear Magnetic Resonance Studies of Topological Insulators and Materials with a Large Spin-Orbit Coupling

    Science.gov (United States)

    Nisson, David Mark

    Nuclear magnetic resonance (NMR) studies were performed on large single crystals of the topological insulator materials Bi2Se 3 and Bi2Te2Se, as well as the doped topological superconductor candidate CuxBi2Se3. Samples were grown using the facilities of the Department of Physics at the University of California, Davis. Bi2Se3 crystals were grown under different conditions to control the intrinsic concentration of carrier electrons, which arises from an inherent tendency for Se vacancies to form during growth. The electrical properties, including carrier concentration of each sample, were then characterized by electrical transport measurements. Frequency swept 209Bi spectra for these samples reveal a relatively weak electric field gradient producing a splitting of about 160 kHz, and a shift that depends on the carrier concentration. The correlation between shift and intrinsic carrier concentration determines the hyperfine coupling strength between the Bi nuclei and the bulk carrier electrons. The spin-lattice relaxation rate T1--1 was also measured as a function of temperature. It is mostly temperature-independent, indicating that in samples of Bi2Se3 grown by the Bridgman method, relaxation may occur by spin diffusion to impurities rather than by previously reported mechanisms. Nuclear magnetic resonance measurements were also performed on single crystals of Bi2Se3 as a function of the angle between the field and the c-axis of the crystal lattice. These frequency-swept measurements revealed anomalous behavior that deviated significantly from what would be expected of the angular dependence of the resonance spectrum. Powder samples reveal spectra that differ still from the expectations from the single-crystal data. These phenomena are explained in part by the fact that the nutation time tpi/2) depends on the angle as a result of overlap between the central and satellite transitions, but may in addition be the result of screening of the radiofrequency field by the

  10. Spin filter effect at room temperature in GaN/GaMnN ferromagnetic resonant tunneling diode

    OpenAIRE

    Wójcik, P.; J. Adamowski; Wołoszyn, M.; Spisak, B. J.

    2013-01-01

    We have investigated the spin current polarization without the external magnetic field in the resonant tunneling diode with the emitter and quantum well layers made from the ferromagnetic GaMnN. For this purpose we have applied the self-consistent Wigner-Poisson method and studied the spin-polarizing effect of the parallel and antiparallel alignment of the magnetization in the ferromagnetic layers. The results of our calculations show that the antiparallel magnetization is much more advantage...

  11. Myosin cross-bridge orientation in rigor and in the presence of nucleotide studied by electron spin resonance.

    OpenAIRE

    Ajtai, K; French, A R; Burghardt, T P

    1989-01-01

    The tilt series electron spin resonance (ESR) spectrum from muscle fibers decorated with spin labeled myosin subfragment 1 (S1) was measured from fibers in rigor and in the presence of MgADP. ESR spectra were measured at low amplitude modulation of the static magnetic field to insure that a minimum of spectral lineshape distortion occurs. Ten tilt series ESR data sets were fitted simultaneously by the model-independent methodology described in the accompanying paper (Burghardt, T. P., and A. ...

  12. On the spin distribution in bridged anthracene-viologen molecules : an electron-nuclear double resonance study

    OpenAIRE

    Sariciftci, Serdar; Werner, Andreas; Grupp, Arthur; Mehring, Michael; Götz, Günther; Bäuerle, Peter; Effenberger, Franz

    1992-01-01

    Studies on the spin distribution in the radical state of anthracene-σ bridge viologen supermolecules with different bridge units are reported. Electronnuclear double resonance experiments (ENDOR) were performed on electrochemically reduced molecules. Proton hyperfine coupling constants at different molecular sites were obtained and are discussed in detail. The experimentally determined values are compared with quantum chemical calculations of the INDO type. The observed spin distribution...

  13. Theoretical grounds of relativistic methods for calculation of spin–spin coupling constants in nuclear magnetic resonance spectra

    Science.gov (United States)

    Rusakova, I. L.; Rusakov, Yu Yu; Krivdin, L. B.

    2016-04-01

    The theoretical grounds of the modern relativistic methods for quantum chemical calculation of spin–spin coupling constants in nuclear magnetic resonance spectra are considered. Examples and prospects of application of relativistic calculations of these constants in the structural studies of organic and heteroorganic compounds are discussed. Practical recommendations on relativistic calculations of spin–spin coupling constants using the available software are given. The bibliography includes 622 references.

  14. WURST-QCPMG sequence and "spin-lock" in 14N nuclear quadrupole resonance

    Science.gov (United States)

    Gregorovič, Alan; Apih, Tomaž

    2013-08-01

    14N nuclear quadrupole resonance (NQR) is a promising method for the analysis of pharmaceuticals or for the detection of nitrogen based illicit compounds, but so far, the technique is still not widely used, mostly due to the very low sensitivity. This problem is already acute in the preliminary NQR stage, when a compound is being examined for the first time and the NQR frequencies are being searched for, by scanning a wide frequency range step-by-step. In the present work, we experimentally show how to increase the efficiency of this initial stage by using a combination of a wideband excitation achieved with frequency swept pulses (WURST) and a "spin-lock" state obtained with a quadrupolar-CPMG (QCPMG) sequence. In the first part we show that WURST pulses provide a much larger excitation bandwidth compared to common rectangular pulses. This increased bandwidth allows to increase the frequency step and reduces the total number of steps in a scanning stage. In the second part we show that the "spin-lock" decay time T2eff obtained with the WURST-QCPMG combination is practically identical with the T2eff obtained with the most common "spin-lock" sequence, the SLSE, despite a very different nature and length of excitation pulses. This allows for a substantial S/N increase through echo averaging in every individual step and really allows to exploit all the advantages of the wider excitation in the NQR frequency scanning stage. Our experimental results were obtained on a sample of trinitrotoluene, but identical behavior is expected for all compounds where a "spin-lock" state can be created.

  15. Distinguishing black-hole spin-orbit resonances by their gravitational wave signatures. II. Full parameter estimation

    Science.gov (United States)

    Trifirò, Daniele; O'Shaughnessy, Richard; Gerosa, Davide; Berti, Emanuele; Kesden, Michael; Littenberg, Tyson; Sperhake, Ulrich

    2016-02-01

    Gravitational waves from coalescing binary black holes encode the evolution of their spins prior to merger. In the post-Newtonian regime and on the precession time scale, this evolution has one of three morphologies, with the spins either librating around one of two fixed points ("resonances") or circulating freely. In this paper we perform full parameter estimation on resonant binaries with fixed masses and spin magnitudes, changing three parameters: a conserved "projected effective spin" ξ and resonant family Δ Φ =0 ,π (which uniquely label the source); the inclination θJ N of the binary's total angular momentum with respect to the line of sight (which determines the strength of precessional effects in the waveform); and the signal amplitude. We demonstrate that resonances can be distinguished for a wide range of binaries, except for highly symmetric configurations where precessional effects are suppressed. Motivated by new insight into double-spin evolution, we introduce new variables to characterize precessing black hole binaries which naturally reflects the time scale separation of the system and therefore better encode the dynamical information carried by gravitational waves.

  16. Observation of overlapping spin-1 and spin-3 D0K- resonances at mass 2.86 GeV/c2.

    Science.gov (United States)

    Aaij, R; Adeva, B; Adinolfi, M; Affolder, A; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Anderson, J; Andreassen, R; Andreotti, M; Andrews, J E; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Batozskaya, V; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bettler, M-O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Borsato, M; Bowcock, T J V; Bowen, E; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brodzicka, J; Brook, N H; Brown, H; Bursche, A; Busetto, G; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Campana, P; Campora Perez, D; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Cenci, R; Charles, M; Charpentier, Ph; Chefdeville, M; Chen, S; Cheung, S-F; Chiapolini, N; Chrzaszcz, M; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Coquereau, S; Corti, G; Corvo, M; Counts, I; Couturier, B; Cowan, G A; Craik, D C; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Dalseno, J; David, P; David, P N Y; Davis, A; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Silva, W; De Simone, P; Decamp, D; Deckenhoff, M; Del Buono, L; Déléage, N; Derkach, D; Deschamps, O; Dettori, F; Di Canto, A; Dijkstra, H; Donleavy, S; Dordei, F; Dorigo, M; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dreimanis, K; Dujany, G; Dupertuis, F; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Ely, S; Esen, S; Evans, H-M; Evans, T; Falabella, A; Färber, C; Farinelli, C; Farley, N; Farry, S; Fay, Rf; Ferguson, D; Fernandez Albor, V; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Fu, J; Furfaro, E; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; García Pardiñas, J; Garofoli, J; Garra Tico, J; Garrido, L; Gaspar, C; Gauld, R; Gavardi, L; Gavrilov, G; Geraci, A; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianelle, A; Gianì, S; Gibson, V; Giubega, L; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gotti, C; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Griffith, P; Grillo, L; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Hampson, T; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; He, J; Head, T; Heijne, V; Hennessy, K; Henrard, P; Henry, L; Hernando Morata, J A; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hoballah, M; Hombach, C; Hulsbergen, W; Hunt, P; Hussain, N; Hutchcroft, D; Hynds, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jaton, P; Jawahery, A; Jing, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kaballo, M; Kandybei, S; Kanso, W; Karacson, M; Karbach, T M; Karodia, S; Kelsey, M; Kenyon, I R; Ketel, T; Khanji, B; Khurewathanakul, C; Klaver, S; Klimaszewski, K; Kochebina, O; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Korolev, M; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kurek, K; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanfranchi, G; Langenbruch, C; Langhans, B; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J-P; Lefèvre, R; Leflat, A; Lefrançois, J; Leo, S; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Likhomanenko, T; Liles, M; Lindner, R; Linn, C; Lionetto, F; Liu, B; Lohn, S; Longstaff, I; Lopes, J H; Lopez-March, N; Lowdon, P; Lu, H; Lucchesi, D; Luo, H; Lupato, A; Luppi, E; Lupton, O; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Malde, S; Malinin, A; Manca, G; Mancinelli, G; Mapelli, A; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marino, P; Märki, R; Marks, J; Martellotti, G; Martens, A; Martín Sánchez, A; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massafferri, A; Matev, R; Mathe, Z; Matteuzzi, C; Mazurov, A; McCann, M; McCarthy, J; McNab, A; McNulty, R; McSkelly, B; Meadows, B; Meier, F; Meissner, M; Merk, M; Milanes, D A; Minard, M-N; Moggi, N; Molina Rodriguez, J; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Moron, J; Morris, A-B; Mountain, R; Muheim, F; Müller, K; Mussini, M; Muster, B; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Nicol, M; Niess, V; Niet, R; Nikitin, N; Nikodem, T; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Onderwater, G; Orlandea, M; Otalora Goicochea, J M; Owen, P; Oyanguren, A; Pal, B K; Palano, A; Palombo, F; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Patrignani, C; Pazos Alvarez, A; Pearce, A; Pellegrino, A; Pepe Altarelli, M; Perazzini, S; Perez Trigo, E; Perret, P; Perrin-Terrin, M; Pescatore, L; Pesen, E; Petridis, K; Petrolini, A; 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    2014-10-17

    The resonant substructure of B(s)(0) → D(0)K(-)π(+) decays is studied using a data sample corresponding to an integrated luminosity of 3.0 fb(-1) of pp collision data recorded by the LHCb detector. An excess at m(D(0)K(-))≈ 2.86 GeV/c(2) is found to be an admixture of spin-1 and spin-3 resonances. Therefore, the D(sJ)*(2860)(-) state previously observed in inclusive e(+)e(-) → D(0)K(-)X and pp → D(0)K(-)X processes consists of at least two particles. This is the first observation of a heavy flavored spin-3 resonance, and the first time that any spin-3 particle has been seen to be produced in B decays. The masses and widths of the new states and of the D(s2)*(2573)(-) meson are measured, giving the most precise determinations to date. PMID:25361252

  17. Observation of overlapping spin-1 and spin-3 $\\overline{D}^0 K^-$ resonances at mass $2.86 {\\rm GeV}/c^2$

    CERN Document Server

    Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassen, Rolf; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belogurov, Sergey; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Bjørnstad, Pål Marius; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borgia, Alessandra; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Brambach, Tobias; van den Brand, Johannes; Bressieux, Joël; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Brown, Henry; Bursche, Albert; Busetto, Giovanni; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Ciba, Krzystof; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Counts, Ian; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pascal; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Di Canto, Angelo; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; 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Gavardi, Laura; Gavrilov, Gennadii; Geraci, Angelo; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, Vladimir; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Hampson, Thomas; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Hunt, Philip; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jaton, Pierre; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kaballo, Michael; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karbach, Moritz; Karodia, Sarah; Kelsey, Matthew; Kenyon, Ian; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kozlinskiy, Alexandr; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kurek, Krzysztof; Kvaratskheliya, Tengiz; La Thi, Viet Nga; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leo, Sabato; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Lohn, Stefan; Longstaff, Iain; Lopes, Jose; Lopez-March, Neus; Lowdon, Peter; Lu, Haiting; Lucchesi, Donatella; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Machikhiliyan, Irina V; Maciuc, Florin; Maev, Oleg; Malde, Sneha; Malinin, Alexander; Manca, Giulia; Mancinelli, Giampiero; Mapelli, Alessandro; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martens, Aurelien; Martín Sánchez, Alexandra; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathe, Zoltan; Matteuzzi, Clara; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; McSkelly, Ben; Meadows, Brian; Meier, Frank; Meissner, Marco; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Moggi, Niccolò; Molina Rodriguez, Josue; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Müller, Katharina; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Nicol, Michelle; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Oggero, Serena; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Orlandea, Marius; Otalora Goicochea, Juan Martin; Owen, Patrick; Oyanguren, Maria Arantza; Pal, Bilas Kanti; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parkes, Christopher; Parkinson, Christopher John; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pazos Alvarez, Antonio; Pearce, Alex; Pellegrino, Antonio; Pepe Altarelli, Monica; Perazzini, Stefano; Perez Trigo, Eliseo; Perret, Pascal; Perrin-Terrin, Mathieu; Pescatore, Luca; Pesen, Erhan; Petridis, Konstantin; Petrolini, Alessandro; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Playfer, Stephen; Plo Casasus, Maximo; Polci, Francesco; Poluektov, Anton; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Rachwal, Bartolomiej; Rademacker, Jonas; Rakotomiaramanana, Barinjaka; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vincente; Roa Romero, Diego; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruffini, Fabrizio; Ruiz, Hugo; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrie, Mauro; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Seco, Marcos; Semennikov, Alexander; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Anthony; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Sparkes, Ailsa; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Subbiah, Vijay Kartik; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szilard, Daniela; Szumlak, Tomasz; T'Jampens, Stephane; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Tran, Minh Tâm; Tresch, Marco; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ubeda Garcia, Mario; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; Voss, Helge; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Whitehead, Mark; Wicht, Jean; Wiedner, Dirk; Wilkinson, Guy; Williams, Matthew; Williams, Mike; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wu, Suzhi; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Wen Chao; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zvyagin, Alexander

    2014-01-01

    The resonant substructure of $B_s^0 \\rightarrow \\overline{D}^0 K^- \\pi^+$ decays is studied using a data sample corresponding to an integrated luminosity of $3.0\\,{\\rm fb}^{-1}$ of $pp$ collision data recorded by the LHCb detector. An excess at $m(\\overline{D}^0 K^-) \\approx 2.86 {\\rm GeV}/c^2$ is found to be an admixture of spin-1 and spin-3 resonances. Therefore the $D^*_{sJ}(2860)^-$ state previously observed in inclusive $e^+e^- \\rightarrow \\overline{D}^0 K^- X$ and $pp \\rightarrow \\overline{D}^0 K^- X$ processes consists of at least two particles. This is the first observation of a heavy flavoured spin-3 resonance, and the first time that any spin-3 particle has been seen to be produced in $B$ decays. The masses and widths of the new states and of the $D^*_{s2}(2573)^-$ meson are measured, giving the most precise determinations to date.

  18. Sensitive determination of the spin polarization of optically pumped alkali-metal atoms using near-resonant light.

    Science.gov (United States)

    Ding, Zhichao; Long, Xingwu; Yuan, Jie; Fan, Zhenfang; Luo, Hui

    2016-01-01

    A new method to measure the spin polarization of optically pumped alkali-metal atoms is demonstrated. Unlike the conventional method using far-detuned probe light, the near-resonant light with two specific frequencies was chosen. Because the Faraday rotation angle of this approach can be two orders of magnitude greater than that with the conventional method, this approach is more sensitive to the spin polarization. Based on the results of the experimental scheme, the spin polarization measurements are found to be in good agreement with the theoretical predictions, thereby demonstrating the feasibility of this approach. PMID:27595707

  19. Producing Radical-Free Hyperpolarized Perfusion Agents for In Vivo Magnetic Resonance Using Spin-Labeled Thermoresponsive Hydrogel.

    Science.gov (United States)

    Cheng, Tian; Mishkovsky, Mor; Junk, Matthias J N; Münnemann, Kerstin; Comment, Arnaud

    2016-07-01

    Dissolution dynamic nuclear polarization (DNP) provides a way to tremendously improve the sensitivity of nuclear magnetic resonance experiments. Once the spins are hyperpolarized by dissolution DNP, the radicals used as polarizing agents become undesirable since their presence is an additional source of nuclear spin relaxation and their toxicity might be an issue. This study demonstrates the feasibility of preparing a hyperpolarized [1-(13) C]2-methylpropan-2-ol (tert-butanol) solution free of persistent radicals by using spin-labeled thermoresponsive hydrophilic polymer networks as polarizing agents. The hyperpolarized (13) C signal can be detected for up to 5 min before the spins fully relax to their thermal equilibrium. This approach extends the applicability of spin-labeled thermoresponsive hydrogel to the dissolution DNP field and highlights its potential as polarizing agent for preparing neat slowly relaxing contrast agents. The hydrogels are especially suited to hyperpolarize deuterated alcohols which can be used for in vivo perfusion imaging. PMID:27184565

  20. Resonant Spin-Flavor Conversion of Supernova Neutrinos: Dependence on Electron Mole Fraction

    CERN Document Server

    Yoshida, T; Kimura, K; Yokomakura, H; Kawagoe, S; Kajino, T

    2009-01-01

    Detailed dependence of resonant spin-flavor (RSF) conversion of supernova neutrinos on electron mole fraction Ye is investigated. Supernova explosion forms a hot-bubble and neutrino-driven wind region of which electron mole fraction exceeds 0.5 in several seconds after the core collapse. When a higher resonance of the RSF conversion is located in the innermost region, flavor change of the neutrinos strongly depends on the sign of 1-2Ye. At an adiabatic high RSF resonance the flavor conversion of bar{nu}_e -> nu_{mu,tau} occurs in Ye 0.5 and inverted mass hierarchy. In other cases of Ye values and mass hierarchies, the conversion of nu_e -> bar{nu}_{mu,tau} occurs. The final bar{nu}_e spectrum is evaluated in the cases of Ye 0.5 taking account of the RSF conversion. Based on the obtained result, time variation of the event number ratios of low bar{nu}_e energy to high bar{nu}_e energy is discussed. In normal mass hierarchy, an enhancement of the event ratio should be seen in the period when the electron frac...

  1. Precise beam energy measurement using resonant spin depolarization in the SOLEIL storage ring

    International Nuclear Information System (INIS)

    The average electron beam energy for the operational mode of 400 mA in 416 bunches in the SOLEIL storage ring was measured to be 2.73724±0.00016 GeV with an accuracy of 5.9×10−5 using the method of resonant spin depolarization (RSD). A Touschek-dominated electron beam was excited using a shaker magnet, and the beam polarization and depolarization were monitored using the change in beam lifetime and beam loss rate. To establish the primary condition that is required to perform energy measurement using the RSD method, the radiative beam polarization was first simulated using the SLIM beam dynamics code and then measured using the relative increase of beam lifetime for a Touschek-dominated electron beam. With a fast frequency sweep rate, the main depolarization resonance to be used to extract the beam energy, along with sidebands within the range of frequency sweep, was identified during our first trials. Sweeping the frequency of the excitation field around the main resonance with a slower frequency sweep rate, the beam energy measurement accuracy was increased from 1.7×10−4 to 5.9×10−5. Finally, the effects of closed orbit distortions on the radiative polarization and measured energy accuracy are discussed.

  2. Electron spin resonance and electron spin echo modulation spectroscopic studies on the structure and reactivity of Pd(I) species in SAPO-11 molecular sieves

    International Nuclear Information System (INIS)

    This paper explores the possibility of using Pd ions in SAPO-11 by adding [Pd(NH3)4]2+ during the synthesis of SAPO-11 to form PdSAPO-11, which is compared with solid-state ion exchange PdSAPO-11 and impregnation PdH-SAPO-11 in which palladium is in an extraframework position. Electron spin resonance and electron spin echo modulation spectroscopies are used to determine if the palladium position in PdSAPO-11 is located in a framework or extraframework

  3. Properties of mixtures of cholesterol with phosphatidylcholine or with phosphatidylserine studied by (13)C magic angle spinning nuclear magnetic resonance.

    OpenAIRE

    Epand, Richard M.; Bain, Alex D; Sayer, Brian G; Bach, Diana; Wachtel, Ellen

    2002-01-01

    The behavior of cholesterol is different in mixtures with phosphatidylcholine as compared with phosphatidylserine. In (13)C cross polarization/magic angle spinning nuclear magnetic resonance spectra, resonance peaks of the vinylic carbons of cholesterol are a doublet in samples containing 0.3 or 0.5 mol fraction cholesterol with 1-palmitoyl-2-oleoyl phosphatidylserine (POPS) or in cholesterol monohydrate crystals, but a singlet with mixtures of cholesterol and 1-palmitoyl-2-oleoyl phosphatidy...

  4. Electron spin resonance dating of teeth from Western Brazilian megafauna - preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, Angela, E-mail: angela.kinoshita@usc.br [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto-SP (Brazil); Universidade Sagrado Coracao, Rua Irma Arminda 10-50, 17011-160 Bauru - Sao Paulo (Brazil); Jose, Flavio A. [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto-SP (Brazil); Sundaram, Dharani; Paixao, Jesus da S.; Soares, Isabella R.M. [Universidade Federal de Mato Grosso, Departamento de Geologia Geral, 78090-000 Cuiaba-MT (Brazil); Figueiredo, Ana Maria [Instituto de Pesquisas Energeticas e Nucleares (IPEN), 05422-970 Sao Paulo-SP (Brazil); Baffa, Oswaldo [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto-SP (Brazil)

    2011-09-15

    Electron Spin Resonance (ESR) was applied to determine ages of Haplomastodon teeth from Western Brazilian Megafauna. The Equivalent Doses (D{sub e}) of (1.3 {+-} 0.2)kGy, (800 {+-} 100)Gy and (140 {+-} 20)Gy were found and the software ROSY ESR dating was employed to convert D{sub e} in age, using isotope concentrations determined by neutron activation analysis (NAA) and other information, resulting in (500 {+-} 100)ka, (320 {+-} 50) and (90 {+-} 10)ka considering the Combination Uptake (CU) model for Uranium uptake, set as an Early Uptake (EU) for dentine and Linear Uptake (LU) for enamel. There are scarce reports about Pleistocene Megafauna in this area. This paper presents the first dating of megafauna tooth and this study could contribute to improve the knowledge about the paleoclimate and paleoenvironment of this region and prompt more investigations in this area.

  5. Inversion of electron spin resonance signal of P1-center in synthetic crystalline diamond

    International Nuclear Information System (INIS)

    We have studied the electron spin resonance (ESR) of a 0.59 carat synthetic diamond single crystal at room temperature. The crystal was grown on a 'split-sphere' apparatus in the Fe-Ni-C system by the temperature gradient method. After high-temperature/high-pressure treatment of the diamond, it was observed that as the microwave power supplied to the sample increased from 70 μW to 70 mW in an H102 cavity, the ESR signal from the P1 center (a nitrogen atom substituting for carbon at a lattice point of the diamond crystal: C-form nitrogen) is inverted. In the original diamond (before high-temperature/high-pressure treatment), no inversion of the ESR signal was observed. (authors)

  6. Experimental determination of the Jπ components of the spin-dipole resonance in 12B

    International Nuclear Information System (INIS)

    The inclusive C12(d->,He2) and exclusive C12(d->,He2+n) reactions have been studied with a beam energy of 171 MeV and scattering angles for the (d,He2) reaction θ=0 deg. and 3 deg. The studies focused on the separation of the isovector spin-dipole resonance (IVSGDR) into its components by measuring tensor-analysing powers and observing the direct neutron decay to the low-lying proton-hole states in 11B. Merging the information obtained from both measurements resulted in the first-time verification of model-independent predictions of tensor-analysing powers at extreme forward angles and the experimental decomposition of the IVSGDR into its Jπ components. The experimental results are in reasonable agreement with theoretical estimates based on shell-model calculations

  7. Electron Spin Resonance Dating of Some Animal Teeth Enamel and Shell Fossils

    International Nuclear Information System (INIS)

    Full text: Electron spin resonance (ESR) dating was conducted for some ungulate tooth enamel samples and shell fossils of the the Tham Lod rock shelter Area I (S23W10) located in Highland Archaeology Project in Pang Mapha District, Mae Hong Son Province, Thailand. Age estimation for wave-induced breaching of the cavity and initial sand deposition (Level 19-29) was 33,200 - 18,700 years and 32,300 years for teeth enamel and the shell fossils of Nodularia scobinata sp. (Carditidae) respectively. ESR spectra showed g-factor g1 (gll, gcenter) = 2.0030 - 2.0036, g2 = 2.0040 - 2.0041 and g3 (g?) = 1.997 - 1.9988 formed by CO2- orthorhombic free radical for teeth enamel and g-factor (gcenter) = 2.0042 + 0.0003 formed by SO3- free radical for fresh shell fossils

  8. Electron spin resonance probed competing states in NiMnInSi Heusler alloy

    Science.gov (United States)

    Chen, Y. S.; Lin, J. G.; Titov, I. S.; Granovsky, A. B.

    2016-06-01

    Shape memory Heusler alloy Ni50Mn35In12Si3 is investigated with electron spin resonance (ESR) technique in a temperature range of 200-300 K. ESR is a dynamic probe allowing us to separate the responses from various magnetic phases, thus to study the complex phase transitions. The sample shows three transition temperatures: TcA (271 K), TM (247 K) and TcM (212 K), where TcA is the Curie temperature of austenitic phase, TM and TcM are the temperatures of magnetostructural martensitic transition and the Curie temperature of martensitic phase, respectively. Furthermore, ESR data reveals the coexistence of two magnetic modes in whole temperature range of 200-300 K. Particularly in martensitic phase, two magnetic modes are attributed to two different kinds of lattice deformation, the slip and twinning deformations.

  9. The use of sugar pellets in ESR [electron spin resonance] dosimetry

    International Nuclear Information System (INIS)

    Table sugar (sucrose) is a convenient, common, tissue-equivalent material suitable for electron spin resonance (ESR) dosimetry of ionising radiation. The simple free radical signal in irradiated sugar is stabilised if the sugar is made into pellets using an inert silicone elastomer (Dow Corning 732). Such pellets, which offer greater convenience and signal stability and reproducibility, have been prepared and tested for their radiation response, sensitivity and post-irradiation stability. Irradiated sugar is detectable at ≥0.1 Gy, the signal intensity is linear with dose, and the fading of the signal, post-irradiation, is minimal for samples kept under ambient conditions. These pellets themselves, given sufficient post-irradiation signal stability, may be useful for environmental monitoring to determine long-term exposures in remote areas or at strategic locations. (Author)

  10. ESR (electron spin resonance)-determined osmotic behavior of bull spermatozoa

    Energy Technology Data Exchange (ETDEWEB)

    Du, J.; Kleinhans, F.W.; Spitzer, V.J.; Critser, J.K. (Methodist Hospital, Indianapolis, IN (USA). Dept. of Medical Research); Horstman, L. (Purdue Univ., Lafayette, IN (USA). School of Veterinary Medicine); Mazur, P. (Oak Ridge National Lab., TN (USA))

    1990-01-01

    Our laboratories are pursuing a fundamental approach to the problems of semen cryopreservation. For many cell types (human red cells, yeast, HeLa) it has been demonstrated that there is an optimum cooling rate for cryopreservation. Faster rates allow insufficient time for cell dehydration and result in intracellular ice formation and cell death. It is possible to predict this optimal rate provided that the cell acts as an ideal osmometer and several other cell parameters are known such as the membrane hydraulic conductivity. It is the purpose of this work to examine the osmotic response of bull sperm to sucrose and NaCl utilizing electron spin resonance (ESR) to measure cell volume. For calibration purposes we also measured the ESR response of human red cells (RBC), the osmotic response of which is well documented with other methods. 15 refs., 1 fig.

  11. DETECTION OF SOME IRRADIATED NUTS BY ELECTRON SPIN RESONANCE (ESR) TECHNIQUE

    International Nuclear Information System (INIS)

    The present investigation was carried out to establish the electron spin resonance (ESR) detection method for identifying irradiated nuts (almond and pistachio). Samples were irradiated with 2, 4 and 6 kGy and stored at room temperature (25± 20C) for six months to study the possibility of detecting its previous irradiation treatments by ESR spectroscopy. Analysis was carried out just after irradiation treatment and during ambient storage period. The ESR signal intensities of irradiated samples were markedly increased correspondingly with irradiation dose as a result of free radicals generated by gamma irradiation so, all irradiated samples under investigation could be differentiated from non-irradiated ones immediately after irradiation treatment. The decay in radicals responsible of ESR signals showed the identification of irradiated almond (shell or edible part) and pistachio (edible part) was impossible after six months of ambient storage

  12. Response of a coupled two-spin system to on-resonance amplitude modulated RF pulses

    Science.gov (United States)

    Zhou, Jinyuan; Ye, Chaohui; Sanctuary, B. C.

    A weakly scalar-coupled two-spin system subjected to two amplitude modulated RF pulses on exact resonance is treated by means of the rotation operator approach. The theory presented here enables coherence evolution to be evaluated by the routine procedure and to be expressed in analytical form. The evolution behaviour from the equilibrium state is discussed in some detail. It is shown that the application of rotation matrix and quaternion elements clarifies evolution expressions. The numerical calculation is performed by way of quaternions. Examples of BURP (band-selective, uniform response, purephase) and sinc-shaped RF pulses are given and the case of time-symmetrical RF pulses is analysed further.

  13. Identification of irradiated peppers by electron spin resonance, thermoluminescence and viscosity

    International Nuclear Information System (INIS)

    White and black pepper purchased in local retailers were analysed by electron spin resonance (ESR), thermoluminescence (TL) and viscosimetry (VISC) in order to establish a viable method for identifying possibly irradiated peppers. Samples studied were non irradiated or irradiated in a cobalt-60 plant with the absorbed doses of 3, 5, 7 and 10 kGy. Confirming the data found in the literature TL was revealed by our results the best method to identify irradiated peppers. Nevertheless, the dose received by the samples could not be estimated. The ESR signal of irradiated peppers is similar to the spectrum of cellulose radical but very short lived at ambient temperature. The study on the alteration of viscosity of heat-treated alkaline pepper suspensions indicate that VISC is a very promising method for detection of irradiated peppers. (Author)

  14. Electron spin resonance measurement of radical scavenging activity of Aronia melanocarpa fruit juice

    Science.gov (United States)

    Valcheva-Kuzmanova, Stefka; Blagović, Branka; Valić, Srećko

    2012-01-01

    Background: The fruits of Aronia melanocarpa (Michx.) Elliot contain large amounts of phenolic substances, mainly procyanidins, anthocyanins and other flavonoids, and phenolic acids. The ability of phenolic substances to act as antioxidants has been well established. Objective: In this study, we investigated the radical scavenging activity of A. melanocarpa fruit juice (AMFJ). Materials and Methods: The method used was electron spin resonance (ESR) spectroscopy. The galvinoxyl free radical was used as a scavenging object. AMFJ was added to the galvinoxyl free radical solution. The measure of the radical scavenging activity was the decrease of signal intensity. Results: AMFJ showed a potent antiradical activity causing a strong and rapid decrease of signal intensity as a function of time and juice concentration. This effect of AMFJ was probably due to the activity of its phenolic constituents. Conclusion: The ESR measurements in this study showed a pronounced radical scavenging effect of AMFJ, an important mechanism of its antioxidant activity. PMID:22701293

  15. Electron spin resonance measurement of radical scavenging activity of Aronia melanocarpa fruit juice

    Directory of Open Access Journals (Sweden)

    Stefka Valcheva-Kuzmanova

    2012-01-01

    Full Text Available Background: The fruits of Aronia melanocarpa (Michx. Elliot contain large amounts of phenolic substances, mainly procyanidins, anthocyanins and other flavonoids, and phenolic acids. The ability of phenolic substances to act as antioxidants has been well established. Objective: In this study, we investigated the radical scavenging activity of A. melanocarpa fruit juice (AMFJ. Materials and Methods: The method used was electron spin resonance (ESR spectroscopy. The galvinoxyl free radical was used as a scavenging object. AMFJ was added to the galvinoxyl free radical solution. The measure of the radical scavenging activity was the decrease of signal intensity. Results: AMFJ showed a potent antiradical activity causing a strong and rapid decrease of signal intensity as a function of time and juice concentration. This effect of AMFJ was probably due to the activity of its phenolic constituents. Conclusion: The ESR measurements in this study showed a pronounced radical scavenging effect of AMFJ, an important mechanism of its antioxidant activity.

  16. Detection of organic free radicals in irradiated pepper by electron spin resonance

    International Nuclear Information System (INIS)

    Using electron spin resonance (ESR) spectroscopy, we revealed various free radicals in a Japanese commercially available black pepper before and after γ-irradiation. The representative ESR spectrum of the pepper is composed of a sextet centered at g=2.0, a singlet at the same g-value and a singlet at g=4.0. The first one is attributable to a signal with hyperfine interactions of Mn2+ ion (7.4 mT). The second one is due to an organic free radical. The third one may be originated from Fe3+ ion of the non-hem Fe in proteins. A pair of signals appeared in the black pepper after γ-irradiation. The progressive saturation behavior reconfirmed the signal identification for the radicals in the black pepper. (author)

  17. Photosynthetic Potential of Planets in 3:2 Spin Orbit Resonances

    CERN Document Server

    Brown, S P; Forgan, D H; Raven, J A; Cockell, C S

    2014-01-01

    Photosynthetic life requires sufficient photosynthetically active radiation (PAR) to metabolise. On Earth, plant behaviour, physiology and metabolism are sculpted around the night-day cycle by an endogenous biological circadian clock. The evolution of life was influenced by the Earth-Sun orbital dynamic, which generates the photo-environment incident on the planetary surface. In this work the unusual photo-environment of an Earth-like planet (ELP) in 3:2 spin orbit resonance is explored. Photo-environments on the ELP are longitudinally differentiated, in addition to differentiations relating to latitude and depth (for aquatic organisms) which are familiar on Earth. The light environment on such a planet could be compatible with Earth's photosynthetic life although the threat of atmospheric freeze-out and prolonged periods of darkness would present significant challenges. We emphasise the relationship between the evolution of life on a planetary body with its orbital dynamics.

  18. Electron spin resonance dating of teeth from Western Brazilian megafauna - preliminary results

    International Nuclear Information System (INIS)

    Electron Spin Resonance (ESR) was applied to determine ages of Haplomastodon teeth from Western Brazilian Megafauna. The Equivalent Doses (De) of (1.3 ± 0.2)kGy, (800 ± 100)Gy and (140 ± 20)Gy were found and the software ROSY ESR dating was employed to convert De in age, using isotope concentrations determined by neutron activation analysis (NAA) and other information, resulting in (500 ± 100)ka, (320 ± 50) and (90 ± 10)ka considering the Combination Uptake (CU) model for Uranium uptake, set as an Early Uptake (EU) for dentine and Linear Uptake (LU) for enamel. There are scarce reports about Pleistocene Megafauna in this area. This paper presents the first dating of megafauna tooth and this study could contribute to improve the knowledge about the paleoclimate and paleoenvironment of this region and prompt more investigations in this area.

  19. Spin Ensembles Coupled to Superconducting Resonators: A Scalable Architecture for Solid-State Quantum Computing

    International Nuclear Information System (INIS)

    A design is proposed for scalable solid-state quantum computing, which is based on collectively enhanced magnetic coupling between nitrogen-vacancy center ensembles and superconducting transmission line resonators interconnected by current-biased Josephson junction superconducting phase qubit. In this hybrid system, we realize distant multi-qubit controlled phase gate operations and generate distant multi-qubit entangled W-like states, being indispensable resource to quantum computation. Our proposed architecture consists of solid-state spin ensembles and circuit QED, and could achieve quantum computing in a solid-state environment with high-fidelity and scalable way. The experimental feasibility is discussed, and the implementation efficiency is demonstrated numerically. (general)

  20. Detection of irradiated fruits and vegetables by gas-chromatographic methods and electron spin-resonance

    International Nuclear Information System (INIS)

    Gas chromatographic methods detected some hydrocarbons esp. 17:1, 16:2, 15:0 and 14:1 in irradiated, Avocado, Papaya, Mangoes with 0.75, 1.5, 3.0 kGy and Apricot with 0.5 and 3.0 kGy. The detection of hydrocarbons was clearly at high doses but the low doses need more sensitive conditions using Liquid-Liquid-Gas chromatographic method as used here. Using Electron Spin-Resonance, produce a specific signal from irradiated onion (dried leaves) as well as apricot (hard coat of kernels) after some weeks of irradiation process but not clear with the other foodstuffs. (orig.)

  1. Eddy-current effects on ferromagnetic resonance: Spin wave excitations and microwave screening effects

    Science.gov (United States)

    Flovik, Vegard; Pettersen, Bjørn Holst; Wahlström, Erik

    2016-04-01

    We investigate how controlling induced eddy currents in thin film ferromagnet-normal metal (FM/NM) structures can be used to tailor the local microwave (MW) fields in ferromagnetic resonance (FMR) experiments. The MW fields produced by eddy currents will in general have a relative phase shift with respect to the applied MW field which depends on the sample geometry. The induced fields can thus partially compensate the applied MW field, effectively screening the FM in selected parts of the sample. The highly localized fields produced by eddy currents enable the excitation of spin wave modes with non-zero wave vectors ( k ≠ 0 ), in contrast to the uniform k = 0 mode normally excited in FMR experiments. We find that the orientation of the applied MW field is one of the key parameters controlling the eddy-current effects. The induced currents are maximized when the applied MW field is oriented perpendicular to the sample plane. Increasing the magnitude of the eddy currents results in a stronger induced MW field, enabling a more effective screening of the applied MW field as well as an enhanced excitation of spin wave modes. This investigation underlines that eddy currents can be used to control the magnitude and phase of the local MW fields in thin film structures.

  2. Magnetic dipole-dipole sensing at atomic scale using electron spin resonance STM

    Science.gov (United States)

    Choi, T.; Paul, W.; Rolf-Pissarczyk, S.; MacDonald, A.; Yang, K.; Natterer, F. D.; Lutz, C. P.; Heinrich, A. J.

    Magnetometry having both high magnetic field sensitivity and atomic resolution has been an important goal for applications in diverse fields covering physics, material science, and biomedical science. Recent development of electron spin resonance STM (ESR-STM) promises coherent manipulation of spins and studies on magnetic interaction of artificially built nanostructures, leading toward quantum computation, simulation, and sensors In ESR-STM experiments, we find that the ESR signal from an Fe atom underneath a STM tip splits into two different frequencies when we position an additional Fe atom nearby. We measure an ESR energy splitting that decays as 1/r3 (r is the separation of the two Fe atoms), indicating that the atoms are coupled through magnetic dipole-dipole interaction. This energy and distance relation enables us to determine magnetic moments of atoms and molecules on a surface with high precision in energy. Unique and advantageous aspects of ESR-STM are the atom manipulation capabilities, which allow us to build atomically precise nanostructures and examine their interactions. For instance, we construct a dice cinque arrangement of five Fe atoms, and probe their interaction and energy degeneracy. We demonstrate the ESR-STM technique can be utilized for quantum magnetic sensors.

  3. Spin torque resonant vortex core expulsion for an efficient radio-frequency detection scheme

    Science.gov (United States)

    Cros, V.; Jenkins, A. S.; Lebrun, R.; Bortolotti, P.; Grimaldi, E.; Tsunegi, S.; Kubota, H.; Yakushiji, K.; Fukushima, A.; Yuasa, S.

    It has been proposed by Tulaparkur et al.[1ref] that a high frequency detector based on the so called spin-diode effect in spin transfer oscillators could eventually replace conventional Schottky diodes, due to their nanoscale size, frequency tunability, and large output sensitivity. Although a promising candidate for ICT applications, the output voltage generated from this effect is consistently low. Here we present a scheme for a new type of spintronics-based high frequency detector based on the expulsion of the vortex core of a magnetic tunnel junction. The resonant expulsion of the core leads to a large and sharp change in resistance associated with the difference in magnetoresistance between the vortex ground state and the final C-state, which is predominantly in either the parallel or anti-parallel direction relative to the polariser layer. Interestingly, this reversible effect is independent of the incoming rf current amplitude, offering a compelling perspective for a fast real-time rf threshold detector. REF : EU FP7 Grant (MOSAIC No. ICT-FP7-317950 is acknowledged.

  4. Electron spin resonance investigation of undoped and Li-doped CdWO.sub.4./sub. scintillator crystals

    Czech Academy of Sciences Publication Activity Database

    Buryi, Maksym; Laguta, Valentyn; Hybler, Jiří; Nikl, Martin; Rosa, Jan

    2011-01-01

    Roč. 248, č. 4 (2011), s. 993-996. ISSN 0370-1972 R&D Projects: GA AV ČR IAA100100810 Institutional research plan: CEZ:AV0Z10100521 Keywords : defects * electron spin resonance * scintillators * wolframite Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.316, year: 2011

  5. Use of spin labels to study membrane proteins by high-frequency electron nuclear double resonance spectroscopy

    NARCIS (Netherlands)

    Orlinkskii, S.B.; Borovykh, I.V.; Zielke, V.; Steinhoff, H.J.

    2007-01-01

    The applicability of spin labels to study membrane proteins by high-frequency electron nuclear double resonance spectroscopy is demonstrated. With the use of bacteriorhodopsin embedded in a lipid membrane as an example, the spectra of protons of neighboring amino acids are recorded, electric field g

  6. Resonant X-ray Diffraction Study of the Strongly Spin-Orbit-Coupled Mott Insulator CaIrO3

    Science.gov (United States)

    Ohgushi, Kenya; Yamaura, Jun-ichi; Ohsumi, Hiroyuki; Sugimoto, Kunihisa; Takeshita, Soshi; Tokuda, Akihisa; Takagi, Hidenori; Takata, Masaki; Arima, Taka-hisa

    2013-05-01

    We performed resonant x-ray diffraction experiments at the L absorption edges for the post-perovskite-type compound CaIrO3 with a (t2g)5 electronic configuration. By observing the magnetic signals, we could clearly see that the magnetic structure was a striped ordering with an antiferromagnetic moment along the c axis and that the wave function of a t2g hole is strongly spin-orbit entangled, the Jeff=1/2 state. The observed spin arrangement is consistent with theoretical work predicting a unique superexchange interaction in the Jeff=1/2 state and points to the universal importance of the spin-orbit coupling in Ir oxides, independent of the octahedral connectivity and lattice topology. We also propose that nonmagnetic resonant scattering is a powerful tool for unraveling an orbital state even in a metallic iridate.

  7. Strong coupling of an NV- spin ensemble to a superconducting resonator

    International Nuclear Information System (INIS)

    This thesis is motivated by the idea of hybrid quantum systems, one promising approach to exploit quantum mechanics for information processing. The main challenge in this field is to counteract decoherence - an inevitable companion of every quantum system. Indeed some quantum systems are intrinsically better isolated from their environment and are therefore less prone to the loss of coherence. But it's the ambivalent nature of decoherence that these highly isolated systems are usually very difficult to interact with and coherently control. To overcome these obstacles ideas were born to combine or hybridize different quantum systems with mutually opposing properties - fast control and long coherence times - and take advantage of the prospective better behavior of the combined system. In this thesis, defects in single crystal diamond - negatively-charged nitrogen-vacancy centers (NV- centers) - are chosen as the quantum memory medium. Because an NV- center constitutes a defect in a solid, its combination with other solid-state quantum systems, as electrical circuits based on Josephson junctions, appears natural. In our work we aimed at the integration of a large number of NV- centers in a circuit quantum electrodynamics (cQED) set-up. These circuits, operating at microwave frequencies, are extremely fast and versatile quantum processors but suffer from short coherence times. Usually single microwave photons stored in a resonant circuit act as information carrier between different parts of the chip. As a main result we observe the coherent energy exchange between the NV- color centers and the electromagnetic field of a microwave resonator. We study in detail a number of important aspects of collective magnetic spin-field coupling as the characteristic scaling with the square root of the number of emitters. Additionally we measure weak coupling to 13C nuclear spins mediated by the hyperfine coupling to the NV- electron spins. The quantum memory capabilities of

  8. Spectroscopy study of electron spin resonance of coal oxidation of different rank

    International Nuclear Information System (INIS)

    The present work constitutes an initial step for the knowledge of the coal oxidation, with the purpose of preventing the adverse influences caused by this phenomenon in the physical-chemical characteristics and in the tendency to the spontaneous combustion. Since the knowledge the influence of the free radicals in this process, their relative concentration was measured by means of the use of the technique of resonance spin electron. This technique measures the absorption of electromagnetic radiation, generally in the microwaves region, for the materials that not have electrons matched up in a strong magnetic field. In the essays of oxidation three coal of different range and different characteristics of mass were used and it was studied the influence of the temperature, particle size and the range. The results showed that the coal of Guacheta (bituminous low in volatile) it presents bigger concentration of free radicals, after the reaction with the atmospheric oxygen, with regard to the coal of the Cerrejon (bituminous high in volatile B) and Amaga (bituminous high in volatile C). Although this doesn't indicate that the coal of Guacheta is that more easily is oxidized, but rather it possibly presents stabilization of radicals for resonance. It concluded that there are differences in the oxidation mechanism between coal of different rank and different agglomeration properties

  9. Experimental setup for investigation of nanoclusters at cryogenic temperatures by electron spin resonance and optical spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Mao, S., E-mail: maoshunghost@tamu.edu; Meraki, A.; McColgan, P. T.; Khmelenko, V. V.; Lee, D. M. [Institute for Quantum Science and Engineering and Department of Physics and Astronomy, Texas A and M University, College Station, Texas 77843 (United States); Shemelin, V. [Cornell Laboratory for Accelerator-based Science and Education, Cornell University, Ithaca, New York 14853 (United States)

    2014-07-15

    We present the design and performance of an experimental setup for simultaneous electron spin resonance (ESR) and optical studies of nanoclusters with stabilized free radicals at cryogenic temperatures. A gas mixture of impurities and helium after passing through a RF discharge for dissociation of molecules is directed onto the surface of superfluid helium to form the nanoclusters of impurities. A specially designed ESR cavity operated in the TE{sub 011} mode allows optical access to the sample. The cavity is incorporated into a homemade insert which is placed inside a variable temperature insert of a Janis {sup 4}He cryostat. The temperature range for sample investigation is 1.25–300 K. A Bruker EPR 300E and Andor 500i optical spectrograph incorporated with a Newton EMCCD camera are used for ESR and optical registration, respectively. The current experimental system makes it possible to study the ESR and optical spectra of impurity-helium condensates simultaneously. The setup allows a broad range of research at low temperatures including optically detected magnetic resonance, studies of chemical processes of the active species produced by photolysis in solid matrices, and investigations of nanoclusters produced by laser ablation in superfluid helium.

  10. Field-induced spin reorientation in [Fe/Cr ] n multilayers studied by nuclear resonance reflectivity

    Science.gov (United States)

    Andreeva, M.; Gupta, A.; Sharma, G.; Kamali, S.; Okada, K.; Yoda, Y.

    2015-10-01

    We present depth-resolved nuclear resonance reflectivity studies of the magnetization evolution in [57Fe(3nm ) /Cr (1.2 nm ) ] 10 multilayer under applied external field. The measurements have been performed at the station BL09XU of SPring-8 at different values of the external field (0-1500 Oe). We apply the joint fit of the delayed reflectivity curves and the time spectra of the nuclear resonance reflectivity measured at different grazing angles for enhancement of the depth resolution and reliability of results. We show that the azimuth angle, which is used in all papers devoted to the magnetization profile determination, has a more complicated physical sense due to the partially coherent averaging of the scattering amplitudes from magnetic lateral domains. We describe how to select the true azimuth angle from the determined "effective azimuth angle." Finally we obtain the noncollinear twisted magnetization depth profiles where the spin-flop state appears sequentially in different 57Fe layers at increasing applied field.

  11. Resonant tunneling between two-dimensional layers accounting for spin-orbit interaction

    Science.gov (United States)

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

    2016-05-01

    We present a theory of quantum tunneling between two-dimensional (2D) layers with Rashba and Dresselhaus spin-orbit interaction (SOI) in the layers. Accounting for SOI in the layers leads to a complex pattern in the tunneling characteristic with typical features corresponding to SOI energy. The resonant features strongly depend on the SOI parameters; for clear experimental observation the SOI characteristic energy should exceed the resonant broadening related to the particles' quantum lifetime in the layers. It appears that the experiments on hole tunneling are favorable to meet this criterion. We also consider a promising candidate for observing the effect, that is, p -doped SiGe strained heterostructures. As supported by our calculations, small adjustments of the parameters for experimentally studied AlGaAs/GaAs p -type quantum walls or designing a 2D-2D tunneling experiment for recently fabricated SiGe structures are very likely to reveal the SOI features in the 2D-2D tunneling.

  12. Magnetic phase transitions in ferrite nanoparticles characterized by electron spin resonance

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Arias, Yesica, E-mail: yeika01@hotmail.com; Vázquez-Victorio, Gabriela; Ortega-Zempoalteca, Raul; Acevedo-Salas, Ulises; Valenzuela, Raul [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México D.F. 04510 (Mexico); Ammar, Souad [Laboratoires ITODYS, Université de Paris-Diderot, PRES Sorbonne Paris Cité, CNRS-UMR 7086, 75205 Paris Cedex (France)

    2015-05-07

    Ferrite magnetic nanoparticles in the composition Zn{sub 0.7}Ni{sub 0.3}Fe{sub 2}O{sub 4} were synthesized by the polyol method, with an average size of 8 nm. Electron spin resonance (ESR) measurements were carried out at a frequency of 9.45 GHz in the 100–500 K temperature range. Obtained results exhibited a characteristic ESR signal in terms of resonance field, H{sub res}, linewidth, ΔH, and peak ratio, R, for each magnetic phase. At low temperatures, the ferrimagnetic phase showed low H{sub res}, broad ΔH, and asymmetric R. At high temperatures, these parameters exhibited opposite values: high H{sub res}, small ΔH, and R ∼ 1. For intermediate temperatures, a different phase was observed, which was identified as a superparamagnetic phase by means of zero-field cooling-field cooling and hysteresis loops measurements. The observed differences were explained in terms of the internal fields and especially due to the cubic anisotropy in the ordered phase.

  13. Pulsed electrically detected magnetic resonance study of spin relaxation and recombination in thin-film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Fehr, Matthias; Behrends, Jan; Schnegg, Alexander; Lips, Klaus; Rech, Bernd [Helmholtz-Zentrum Berlin, Silizium Photovoltaik, Berlin (Germany); Astakhov, Oleksander; Finger, Friedhelm [Forschungszentrum Juelich (Germany). IEF-5 Photovoltaik

    2009-07-01

    We have investigated the influence of paramagnetic states on electronic transport processes in thin-film pin solar cells with pulsed Electrically Detected Magnetic Resonance (pEDMR) at X-Band frequency and low temperature (10 K). The solar cells consist of an intrinsic microcrystalline absorber layer and amorphous or microcrystalline n/p contacting layers. In addition to the identification of the participating paramagnetic centres by their g-factors, pEDMR can be used to study the dynamics of the electronic processes in detail. We present measurements of modified EPR pulse sequences in order to identify the dominating relaxation mechanisms within correlated solid-state spin-pairs. By this technique a monitoring of the spin and charge motion is possible. In the outlook we present measurements of the electron spin echo envelope and critically discuss modulations in terms of dipolar coupling within the spin-pairs or hyperfine couplings to surrounding nuclei.

  14. Higher-order Zeeman and spin terms in the electron paramagnetic resonance spin Hamiltonian; their description in irreducible form using Cartesian, tesseral spherical tensor and Stevens' operator expressions.

    Science.gov (United States)

    McGavin, Dennis G; Tennant, W Craighead

    2009-06-17

    In setting up a spin Hamiltonian (SH) to study high-spin Zeeman and high-spin nuclear and/or electronic interactions in electron paramagnetic resonance (EPR) experiments, it is argued that a maximally reduced SH (MRSH) framed in tesseral combinations of spherical tensor operators is necessary. Then, the SH contains only those terms that are necessary and sufficient to describe the particular spin system. The paper proceeds then to obtain interrelationships between the parameters of the MRSH and those of alternative SHs expressed in Cartesian tensor and Stevens operator-equivalent forms. The examples taken, initially, are those of Cartesian and Stevens' expressions for high-spin Zeeman terms of dimension BS(3) and BS(5). Starting from the well-known decomposition of the general Cartesian tensor of second rank to three irreducible tensors of ranks 0, 1 and 2, the decomposition of Cartesian tensors of ranks 4 and 6 are treated similarly. Next, following a generalization of the tesseral spherical tensor equations, the interrelationships amongst the parameters of the three kinds of expressions, as derived from equivalent SHs, are determined and detailed tables, including all redundancy equations, set out. In each of these cases the lowest symmetry, [Formula: see text] Laue class, is assumed and then examples of relationships for specific higher symmetries derived therefrom. The validity of a spin Hamiltonian containing mixtures of terms from the three expressions is considered in some detail for several specific symmetries, including again the lowest symmetry. Finally, we address the application of some of the relationships derived here to seldom-observed low-symmetry effects in EPR spectra, when high-spin electronic and nuclear interactions are present. PMID:21693947

  15. Electron-atom resonances: The complex-scaled multiconfigurational spin-tensor electron propagator method for the 2P Be- shape resonance problem

    Science.gov (United States)

    Tsednee, Tsogbayar; Liang, Liyuan; Yeager, Danny L.

    2015-02-01

    We propose and develop the complex-scaled multiconfigurational spin-tensor electron propagator (CMCSTEP) technique for theoretical determination of resonance parameters with electron-atom and electron-molecule systems including open-shell and highly correlated atoms and molecules. The multiconfigurational spin-tensor electron propagator (MCSTEP) method developed and implemented by Yeager and co-workers in real space gives very accurate and reliable ionization potentials and attachment energies. The CMCSTEP method uses a complex-scaled multiconfigurational self-consistent field (CMCSCF) state as an initial state along with a dilated Hamiltonian where all of the electronic coordinates are scaled by a complex factor. The CMCSCF was developed and applied successfully to resonance problems earlier. We apply the CMCSTEP method to get 2P Be- shape resonance parameters using 14 s 11 p 5 d ,14 s 14 p 2 d , and 14 s 14 p 5 d basis sets with a 2 s 2 p 3 d complete active space. The obtained values of the resonance parameters are compared to previous results. Here CMCSTEP has been developed and used for a resonance problem. It appears to be among the most accurate and reliable techniques. Vertical ionization potentials and attachment energies in real space are typically within ±0.2 eV or better of excellent experimental results and full configuration-interaction calculations with a good basis set. We expect the same sort of agreement in complex space.

  16. The electron spin resonance study of heavily nitrogen doped 6H SiC crystals

    Energy Technology Data Exchange (ETDEWEB)

    Savchenko, D. V., E-mail: dariyasavchenko@gmail.com [Institute of Physics AS CR, Prague 182 21, Czech Republic and V.E. Lashkaryov Institute of Semiconductor Physics, NASU, Kyiv 03028 (Ukraine)

    2015-01-28

    The magnetic and electronic properties of heavily doped n-type 6H SiC samples with a nitrogen concentration of 10{sup 19} and 4 × 10{sup 19 }cm{sup −3} were studied with electron spin resonance (ESR) at 5–150 K. The observed ESR line with a Dysonian lineshape was attributed to the conduction electrons (CE). The CE ESR (CESR) line was fitted by Lorentzian (insulating phase) (T < 40 K) and by Dysonian lineshape (metallic phase) above 40 K, demonstrating that Mott insulator-metal (IM) transition takes place at ∼40 K, accompanied by significant change in the microwave conductivity. The temperature dependence of CESR linewidth follows the linear Korringa law below 40 K, caused by the coupling of the localized electrons (LE) and CE, and is described by the exponential law above 40 K related to the direct relaxation of the LE magnetic moments via excited levels driven by the exchange interaction of LE with CE. The g-factor of the CESR line (g{sub ‖} = 2.0047(3), g{sub ⊥} = 2.0034(3)) is governed by the coupling of the LE of nitrogen donors at hexagonal and quasi-cubic sites with the CE. The sharp drop in CESR line intensity (25–30 K) was explained by the formation of antiferromagnetic ordering in the spin system close to the IM transition. The second broad ESR line overlapped with CESR signal (5–25 K) was attributed to the exchange line caused by the hopping motion of electrons between occupied and non-occupied positions of the nitrogen donors. Two mechanisms of conduction, hopping and band conduction, were distinguished in the range of T = 10–25 K and T > 50 K, respectively.

  17. Resonant X-Ray Diffraction Study of Strongly Spin-Orbit-Coupled Mott Insulator CaIrO3

    OpenAIRE

    Ohgushi, Kenya; Yamaura, Jun-ichi; Ohsumi, Hiroyuki; Sugimoto, Kunihisa; Takeshita, Soshi; Tokuda, Akihisa; Takagi, Hidenori; Takata, Masaki; Arima, Taka-hisa

    2011-01-01

    We performed resonant x-ray diffraction experiments at the $L$ absorption edges for the post-perovskite-type compound CaIrO$_{3}$ with $(t_{2g})^5$ electronic configuration. By observing the magnetic signals, we could clearly see that the magnetic structure was a striped order with an antiferromagnetic moment along the c-axis and that the wavefunction of a $t_{2g}$ hole is strongly spin-orbit entangled, the $J_{\\rm eff} =1/2$ state. The observed spin arrangement is consistent with theoretical...

  18. Mechanism of initiation of oxidation in mayonnaise enriched with fish oil as studied by electron spin resonance spectroscopy

    DEFF Research Database (Denmark)

    Thomsen, M.K.; Jacobsen, Charlotte; Skibsted, L.H.

    2000-01-01

    Electron spin resonance spectroscopy (spin trapping technique) has been used to identify the most important single factor for initiation of lipid oxidation in mayonnaise enriched with fish oil. Low pH increases the formation of radicals during incubation under mildly accelerated conditions at 37...... degreesC as quantified using 12-doxylstearic acid. Sugar, NaCl and potassium sorbate have no effect on radical formation while EDTA (down to 50 mug/g) has an antioxidative effect. Iron bound to phosvitin in egg yolk, inactive at pH similar to6, is considered to be exposed to the solvent (the aqueous phase...

  19. Systematic evaluation of heteronuclear spin decoupling in solid-state NMR at the rotary-resonance conditions in the regime of fast magic-angle spinning.

    Science.gov (United States)

    Sharma, Kshama; Madhu, P K; Agarwal, Vipin

    2016-09-01

    The performance of heteronuclear spin decoupling sequences in solid-state NMR severely degrades when the proton radiofrequency (RF) nutation frequencies (ν1) are close to or at multiples of magic-angle spinning (MAS) frequency (νr) that are referred to as rotary-resonance recoupling conditions (ν1=n·νr). Recently, two schemes, namely, PISSARRO and rCW(ApA), have been shown to be less affected by the problem of MAS and RF interference, specifically at the n=2 rotary-resonance recoupling condition, especially in the fast MAS regime. Here, we systematically evaluate the loss in intensity of several heteronuclear spin decoupling sequences at the n=1, 2 conditions compared to high-power decoupling in the fast-MAS regime. We propose that in the fast-MAS regime (above 40kHz) the entire discussion about RF and MAS interference can be avoided by using appropriate low-power decoupling sequences which give comparable performance to decoupling sequences with high-power (1)H irradiation of ca.195kHz. PMID:27472380

  20. Simulation of electron spin resonance spectroscopy in diverse environments: An integrated approach

    Science.gov (United States)

    Zerbetto, Mirco; Polimeno, Antonino; Barone, Vincenzo

    2009-12-01

    We discuss in this work a new software tool, named E-SpiReS (Electron Spin Resonance Simulations), aimed at the interpretation of dynamical properties of molecules in fluids from electron spin resonance (ESR) measurements. The code implements an integrated computational approach (ICA) for the calculation of relevant molecular properties that are needed in order to obtain spectral lines. The protocol encompasses information from atomistic level (quantum mechanical) to coarse grained level (hydrodynamical), and evaluates ESR spectra for rigid or flexible single or multi-labeled paramagnetic molecules in isotropic and ordered phases, based on a numerical solution of a stochastic Liouville equation. E-SpiReS automatically interfaces all the computational methodologies scheduled in the ICA in a way completely transparent for the user, who controls the whole calculation flow via a graphical interface. Parallelized algorithms are employed in order to allow running on calculation clusters, and a web applet Java has been developed with which it is possible to work from any operating system, avoiding the problems of recompilation. E-SpiReS has been used in the study of a number of different systems and two relevant cases are reported to underline the promising applicability of the ICA to complex systems and the importance of similar software tools in handling a laborious protocol. Program summaryProgram title: E-SpiReS Catalogue identifier: AEEM_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEM_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GPL v2.0 No. of lines in distributed program, including test data, etc.: 311 761 No. of bytes in distributed program, including test data, etc.: 10 039 531 Distribution format: tar.gz Programming language: C (core programs) and Java (graphical interface) Computer: PC and Macintosh Operating system: Unix and Windows Has the code been vectorized or

  1. Detection of reactive oxygen species in isolated, perfused lungs by electron spin resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    Schudt Christian

    2005-07-01

    Full Text Available Abstract Background The sources and measurement of reactive oxygen species (ROS in intact organs are largely unresolved. This may be related to methodological problems associated with the techniques currently employed for ROS detection. Electron spin resonance (ESR with spin trapping is a specific method for ROS detection, and may address some these technical problems. Methods We have established a protocol for the measurement of intravascular ROS release from isolated buffer-perfused and ventilated rabbit and mouse lungs, combining lung perfusion with the spin probe l-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CPH and ESR spectroscopy. We then employed this technique to characterize hypoxia-dependent ROS release, with specific attention paid to NADPH oxidase-dependent superoxide formation as a possible vasoconstrictor pathway. Results While perfusing lungs with CPH over a range of inspired oxygen concentrations (1–21 %, the rate of CP• formation exhibited an oxygen-dependence, with a minimum at 2.5 % O2. Addition of superoxide dismutase (SOD to the buffer fluid illustrated that a minor proportion of this intravascular ROS leak was attributable to superoxide. Stimulation of the lungs by injection of phorbol-12-myristate-13-acetate (PMA into the pulmonary artery caused a rapid increase in CP• formation, concomitant with pulmonary vasoconstriction. Both the PMA-induced CPH oxidation and the vasoconstrictor response were largely suppressed by SOD. When the PMA challenge was performed at different oxygen concentrations, maximum superoxide liberation and pulmonary vasoconstriction occurred at 5 % O2. Using a NADPH oxidase inhibitor and NADPH-oxidase deficient mice, we illustrated that the PMA-induced superoxide release was attributable to the stimulation of NADPH oxidases. Conclusion The perfusion of isolated lungs with CPH is suitable for detection of intravascular ROS release by ESR spectroscopy. We employed this technique to

  2. Electron spin resonance microscopic imaging of oxygen concentration in cancer spheroids

    Science.gov (United States)

    Hashem, Mada; Weiler-Sagie, Michal; Kuppusamy, Periannan; Neufeld, Gera; Neeman, Michal; Blank, Aharon

    2015-07-01

    Oxygen (O2) plays a central role in most living organisms. The concentration of O2 is important in physiology and pathology. Despite the importance of accurate knowledge of the O2 levels, there is very limited capability to measure with high spatial resolution its distribution in millimeter-scale live biological samples. Many of the current oximetric methods, such as oxygen microelectrodes and fluorescence lifetime imaging, are compromised by O2 consumption, sample destruction, invasiveness, and difficulty to calibrate. Here, we present a new method, based on the use of the pulsed electron spin resonance (ESR) microimaging technique to obtain a 3D mapping of oxygen concentration in millimeter-scale biological samples. ESR imaging requires the incorporation of a suitable stable and inert paramagnetic spin probe into the desirable object. In this work, we use microcrystals of a paramagnetic spin probe in a new crystallographic packing form (denoted tg-LiNc-BuO). These paramagnetic species interact with paramagnetic oxygen molecules, causing a spectral line broadening that is linearly proportional to the oxygen concentration. Typical ESR results include 4D spatial-spectral images that give an indication about the oxygen concentration in different regions of the sample. This new oximetry microimaging method addresses all the problems mentioned above. It is noninvasive, sensitive to physiological oxygen levels, and easy to calibrate. Furthermore, in principle, it can be used for repetitive measurements without causing cell damage. The tissue model used in this research is spheroids of Human Colorectal carcinoma cell line (HCT-116) with a typical diameter of ∼600 μm. Most studies of the microenvironmental O2 conditions inside such viable spheroids carried out in the past used microelectrodes, which require an invasive puncturing of the spheroid and are also not applicable to 3D O2 imaging. High resolution 3D oxygen maps could make it possible to evaluate the

  3. First measurement of the double spin asymmetry in (-->)e(-->)p-->e(prime)pi(+)n in the resonance region.

    Science.gov (United States)

    De Vita, R; Anghinolfi, M; Burkert, V D; Dodge, G E; Minehart, R; Taiuti, M; Weller, H; Adams, G; Amaryan, M J; Anciant, E; Armstrong, D S; Asavapibhop, B; Asryan, G; Audit, G; Auger, T; Avakian, H; Bagdasaryan, H; Ball, J P; Barrow, S; Battaglieri, M; Beard, K; Bektasoglu, M; Bianchi, N; Biselli, A S; Boiarinov, S; Bonner, B E; Bosted, P; Bouchigny, S; Branford, D; Brooks, W K; Bueltmann, S; Calarco, J R; Capitani, G P; Carman, D S; Carnahan, B; Cazes, A; Ciciani, L; Cole, P L; Coleman, A; Connelly, J; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J P; De Sanctis, E; Degtyarenko, P V; Demirchyan, R; Denizli, H; Dennis, L; Dharmawardane, K V; Dhuga, K S; Djalali, C; Doughty, D; Dragovitsch, P; Dugger, M; Dytman, S; Eckhause, M; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Empl, A; Farhi, L; Fatemi, R; Feuerbach, R J; Ficenec, J; Forest, T A; Frolov, V; Funsten, H; Gaff, S J; Gai, M; Garçon, M; Gavalian, G; Gilad, S; Gilfoyle, G P; Giovanetti, K L; Girard, P; Golovatch, E; Griffioen, K; Guidal, M; Guillo, M; Gyurjyan, V; Hadjidakis, C; Hancock, D; Hardie, J; Heddle, D; Heimberg, P; Hersman, F W; Hicks, K; Hicks, R S; Holtrop, M; Hu, J; Hyde-Wright, C E; Ishkanov, B S; Ito, M M; Jenkins, D; Joo, K; Kelley, J H; Kellie, J D; Khandaker, M; Kim, K Y; Kim, K; Kim, W; Klein, A; Klein, F J; Klusman, M; Kossov, M; Kramer, L H; Kuang, Y; Kuhn, S E; Lachniet, J; Laget, J M; Lawrence, D; Li, Ji; Livingston, K; Longhi, A; Loukachine, K; Lucas, M; Major, W; Manak, J J; Marchand, C; McAleer, S; McCarthy, J; McNabb, J W C; Mecking, B A; Mestayer, M D; Meyer, C A; Mikhailov, K; Mirazita, M; Miskimen, R; Mokeev, V; Muccifora, V; Mueller, J; Mutchler, G S; Napolitano, J; Nelson, S O; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niyazov, R A; Opper, A K; O'Rielly, G V; Osipenko, M; Park, K; Pasyuk, E; Peterson, G; Philips, S A; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Qin, L M; Raue, B A; Reolon, A R; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Rock, S; Ronchetti, F; Rossi, P; Rowntree, D; Rubin, P D; Sabatié, F; Sabourov, K; Salgado, C; Sapunenko, V; Sargsyan, M; Schumacher, R A; Serov, V S; Shafi, A; Sharabian, Y G; Shaw, J; Skabelin, A V; Smith, E S; Smith, T; Smith, L C; Sober, D I; Sorrell, L; Spraker, M; Stavinsky, A; Stepanyan, S; Stoler, P; Strakovsky, I I; Taylor, S; Tedeschi, D J; Thompson, R; Todor, L; Ungaro, M; Vineyard, M F; Vlassov, A V; Wang, K; Weinstein, L B; Weisberg, A; Weygand, D P; Whisnant, C S; Wolin, E; Yegneswaran, A; Yun, J; Zhang, B; Zhao, J; Zhou, Z

    2002-02-25

    The double spin asymmetry in the (-->)e(-->)p --> e(prime)pi(+)n reaction has been measured for the first time in the resonance region for four-momentum transfer Q2 = 0.35-1.5 GeV(2). Data were taken at Jefferson Lab with the CLAS detector using a 2.6 GeV polarized electron beam incident on a polarized solid NH3 target. Comparison with predictions of phenomenological models shows strong sensitivity to resonance contributions. Helicity-1/2 transitions are found to be dominant in the second and third resonance regions. The measured asymmetry is consistent with a faster rise with Q(2) of the helicity asymmetry A1 for the F(15)(1680) resonance than expected from the analysis of the unpolarized data. PMID:11863951

  4. Using resonance Raman cross-section data to estimate the spin state populations of Cytochromes P450.

    Science.gov (United States)

    Mak, Piotr J; Zhu, Qianhong; Kincaid, James R

    2013-12-01

    The cytochromes P450 (CYPs) are heme proteins responsible for the oxidation of xenobiotics and pharmaceuticals and the biosynthesis of essential steroid products. In all cases, substrate binding initiates the enzymatic cycle, converting ferric low spin (LS) to high-spin (HS), with the efficiency of the conversion varying widely for different substrates, so documentation of this conversion for a given substrate is an important objective. Resonance Raman (rR) spectroscopy can effectively yield distinctive frequencies for the ν3 "spin state marker" bands. Here, employing a reference cytochrome P450 (CYP101), the intensities of the ν3 modes (ILS) and (IHS) relative to an internal standard (sodium sulfate) yield relative populations for the two spin states; i.e., a value of 1.24 was determined for the ratio of the relative cross sections for the ν3 modes. Use of this value was then shown to permit a reliable calculation of relative populations of the two spin states from rR spectra of several other Cytochromes P450. The importance of this work is that, using this information, it is now possible to conveniently document by rR the spin state population without conducting separate experiments requiring different analytical methods, instrumentation and additional sample. PMID:24443630

  5. Effects of spin-forbidden resonances on the recombination of Be-like Si and Be-like Ne

    Energy Technology Data Exchange (ETDEWEB)

    Orban, I; Boehm, S; Schuch, R [Department of Physics, Stockholm University, 10691 Stockholm (Sweden); Loch, S D [Department of Physics, Auburn University, Auburn, AL 36849 (United States); Glans, P, E-mail: istvan.orban@fysik.su.se [Department of Engineering, Physics and Mathematics, Mid Sweden University, 85170 Sundsvall (Sweden)

    2011-06-15

    Recombination through doubly excited states that can be formed only through spin-flip of the excited electrons can give very strong contributions to the recombination rate of Be-like ions. We demonstrate this, in this paper, with the electron-ion recombination spectra of Be-like Ne{sup 6+} and Be-like Si{sup 10+}, recently measured at the CRYRING storage ring. These resonances have significant effects on the plasma rate coefficients. We show that neglect or imprecise calculation of these resonances is responsible for large spreads observed between various theoretical results from the literature.

  6. Generation of constant-amplitude radio-frequency sweeps at a tunnel junction for spin resonance STM

    Science.gov (United States)

    Paul, William; Baumann, Susanne; Lutz, Christopher P.; Heinrich, Andreas J.

    2016-07-01

    We describe the measurement and successful compensation of the radio-frequency transfer function of a scanning tunneling microscope over a wide frequency range (15.5-35.5 GHz) and with high dynamic range (>50 dB). The precise compensation of cabling resonances and attenuations is critical for the production of constant-voltage frequency sweeps for electric-field driven electron spin resonance (ESR) experiments. We also demonstrate that a well-calibrated tunnel junction voltage is necessary to avoid spurious ESR peaks that can arise due to a non-flat transfer function.

  7. Magnetic resonance cisternography using the fast spin echo method for the evaluation of vestibular schwannoma

    Energy Technology Data Exchange (ETDEWEB)

    Nishizawa, Shigeru; Yokoyama, Tetsuo; Uemura, Kenichi [Hamamatsu Univ. School of Medicine, Shizuoka (Japan)

    1999-04-01

    Neuroimaging of vestibular schwannoma was performed with the fat-suppression spoiled gradient recalled acquisition in the steady state (SPGR) method and magnetic resonance (MR) cisternography, which is a fast spin echo method using a long echo train length, for the preoperative evaluation of the lateral extension of the tumor in the internal auditory canal, and the anatomical identification of the posterior semicircular canal and the nerves in the canal distal to the tumor. The SPGR method overestimated the lateral extension in eight cases, probably because of enhancement of the nerves adjacent to the tumor in the canal. The posterior semicircular canal could not be clearly identified, and the cranial nerves in the canal were shown only as a nerve bundle. In contrast, MR cisternography showed clear images of the lateral extension of the tumor and the facial and cochlear nerves adjacent to the tumor in the internal auditory canal. The anatomical location of the posterior semicircular canal was also clearly shown. These preoperative findings are very useful to plan the extent to which the internal auditory canal can be opened, and for intraoperative identification of the nerves in the canal. MR cisternography is less invasive since no contrast material or radiation is required, as with thin-slice high-resolution computed tomography (CT). MR cisternography should replace high-resolution CT for the preoperative neuroradiological evaluation of vestibular schwannoma. (author)

  8. Characterization of fluorine-doped silicon dioxide films by Raman spectroscopy and Electron-spin resonance

    International Nuclear Information System (INIS)

    We have measured Raman and Electron-spin resonance (ESR) spectra of fluorine-doped SiO2 films deposited by two different methods. In high-density plasma (HDP) films, the Raman band at about 490 cm-1 becomes drastically stronger as the F/Si ratio increases, whereas the Raman band from threefold ring defect is independent of the F/Si ratio. The unusual increase of the intensity of the 490 cm-1 band in HDP films has been interpreted in terms of the existence of Si-Si clusters. From a comparison between Raman spectra of HDP film and plasma chemical vapor deposition using tetraethoxysilane (p-TEOS) film with the same F/Si ratios it has been found that HDP film has more Si-Si bonds and threefold ring defects than p-TEOS film. Furthermore, the polarized Raman spectra in the 810 cm-1 bands indicate that inhomogeneous SiO2 clusters of various sizes should exist in the network structure of HDP film. The result of the ESR measurement shows that HDP films have fewer dangling bonds than p-TEOS films. It is considered that many Si-Si clusters, threefold ring defects, and inhomogeneous SiO2 cluster sizes, and the few dangling bonds in HDP films give rise to the film properties of low stress, good adhesion with Si substrate, and low water permeation

  9. Characterization of fluorine-doped silicon dioxide films by Raman spectroscopy and Electron-spin resonance

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, K. [Toray Research Center, Inc. Sonoyama 3-3-7, Otsu, Shiga, 520-8567 (Japan)]. E-mail: keiko_matsuda@trc.toray.co.jp; Yamaguchi, Y. [Toray Research Center, Inc. Sonoyama 3-3-7, Otsu, Shiga, 520-8567 (Japan); Morita, N. [Toray Research Center, Inc. Sonoyama 3-3-7, Otsu, Shiga, 520-8567 (Japan); Matsunobe, T. [Toray Research Center, Inc. Sonoyama 3-3-7, Otsu, Shiga, 520-8567 (Japan); Yoshikawa, M. [Toray Research Center, Inc. Sonoyama 3-3-7, Otsu, Shiga, 520-8567 (Japan)

    2007-06-13

    We have measured Raman and Electron-spin resonance (ESR) spectra of fluorine-doped SiO{sub 2} films deposited by two different methods. In high-density plasma (HDP) films, the Raman band at about 490 cm{sup -1} becomes drastically stronger as the F/Si ratio increases, whereas the Raman band from threefold ring defect is independent of the F/Si ratio. The unusual increase of the intensity of the 490 cm{sup -1} band in HDP films has been interpreted in terms of the existence of Si-Si clusters. From a comparison between Raman spectra of HDP film and plasma chemical vapor deposition using tetraethoxysilane (p-TEOS) film with the same F/Si ratios it has been found that HDP film has more Si-Si bonds and threefold ring defects than p-TEOS film. Furthermore, the polarized Raman spectra in the 810 cm{sup -1} bands indicate that inhomogeneous SiO{sub 2} clusters of various sizes should exist in the network structure of HDP film. The result of the ESR measurement shows that HDP films have fewer dangling bonds than p-TEOS films. It is considered that many Si-Si clusters, threefold ring defects, and inhomogeneous SiO{sub 2} cluster sizes, and the few dangling bonds in HDP films give rise to the film properties of low stress, good adhesion with Si substrate, and low water permeation.

  10. Identification of irradiated wheat by germination test, DNA comet assay and electron spin resonance

    Science.gov (United States)

    Barros, Adilson C.; Freund, Maria Teresa L.; Villavicencio, Ana Lúcia C. H.; Delincée, Henry; Arthur, Valter

    2002-03-01

    In several countries, there has been an increase in the use of radiation for food processing thus improving the quality and sanitary conditions, inhibiting pathogenic microorganisms, delaying the natural aging process and so extending product lifetime. The need to develop analytical methods to detect these irradiated products is also increasing. The goal of this research was to identify wheat irradiated using different radiation doses. Seeds were irradiated with a gamma 60Co source (Gammacell 220 GC) in the Centro de Energia Nuclear na Agricultura and the Instituto de Pesquisas Energéticas e Nucleares. Dose rate used were 1.6 and 5.8kGy/h. Applied doses were 0.0, 0.10, 0.25, 0.50, 0.75, 1.0, and 2.0kGy. After irradiation, seeds were analysed over a 6 month period. Three different detection methods were employed to determine how irradiation had modified the samples. Screening methods consisted of a germination test measuring the inhibition of shooting and rooting and analysis of DNA fragmentation. The method of electron spin resonance spectroscopy allowed a better dosimetric evaluation. These techniques make the identification of irradiated wheat with different doses possible.

  11. Identification of gamma ray irradiated wheat by electron spin resonance, DNA comet assay and germination test

    International Nuclear Information System (INIS)

    In several countries, there has been an increase in the use of radiation for food processing thus improving the quality and sanitary conditions, inhibiting pathogenic microorganisms, delaying the natural aging process and so extending product lifetime. The need to develop analytical methods to detect these irradiated products is also increasing. The goal of this research was to identify wheat irradiated using three different techniques: Electron spin resonance, DNA comet assay and germination test, for comparison. Wheat variety IAC 289 and husked wheat variety IAC 355 was from Instituto Agronomico de Campinas. Grains were irradiated with a gamma 60Co source (Gammacell 220 GC) in the Centro de Energia Nuclear na Agricultura and in the Instituto de Pesquisas Energeticas e Nucleares. Dose rate used were 1.6 kGy/h and 5.8 kGy/h. Applied doses were 0.0 kGy ; 0.10 kGy ; 0.25 kGy ; 0.50 kGy ; 0.75 kGy ; 1.0 kGy and 2.0 kGy. After irradiation, grains were analyzed over a 6 month period. It is possible to use E8R to identify irradiated husked wheat until 3 weeks after the date of irradiation. Comet assay was a qualitative test that we used to identify irradiated wheat at least 6 months after storage. The germination test make possible the identification and the better criteria was the shoot length. (author)

  12. Magnetic resonance cisternography using the fast spin echo method for the evaluation of vestibular schwannoma

    International Nuclear Information System (INIS)

    Neuroimaging of vestibular schwannoma was performed with the fat-suppression spoiled gradient recalled acquisition in the steady state (SPGR) method and magnetic resonance (MR) cisternography, which is a fast spin echo method using a long echo train length, for the preoperative evaluation of the lateral extension of the tumor in the internal auditory canal, and the anatomical identification of the posterior semicircular canal and the nerves in the canal distal to the tumor. The SPGR method overestimated the lateral extension in eight cases, probably because of enhancement of the nerves adjacent to the tumor in the canal. The posterior semicircular canal could not be clearly identified, and the cranial nerves in the canal were shown only as a nerve bundle. In contrast, MR cisternography showed clear images of the lateral extension of the tumor and the facial and cochlear nerves adjacent to the tumor in the internal auditory canal. The anatomical location of the posterior semicircular canal was also clearly shown. These preoperative findings are very useful to plan the extent to which the internal auditory canal can be opened, and for intraoperative identification of the nerves in the canal. MR cisternography is less invasive since no contrast material or radiation is required, as with thin-slice high-resolution computed tomography (CT). MR cisternography should replace high-resolution CT for the preoperative neuroradiological evaluation of vestibular schwannoma. (author)

  13. Gas chromatographic and electron spin resonance investigations of gamma-irradiated frog legs

    Science.gov (United States)

    Morehouse, Kim M.; Ku, Yuoh; Albrecht, Heidi L.; George C., Yang

    Several very sensitive techniques to measure radiation-induced products in frog legs were investigated. Presented here are results from the use of electron spin resonance (ESR) spectroscopy and capillary gas chromatography (GC) to measure radiolysis products in γ-irradiated frog legs. When bone is irradiated, a characteristic ESR signal develops and is easily measured. The intensity of the ESR signal is dose-dependent and stable for several months at room temperature. When triglycerides or fatty acids are irradiated, some of the major stable products formed are hydrocarbons with one less carbon than the precursor fatty acids. These hydrocarbons are formed as the result of the loss of CO 2 during various free radical reactions. A capillary GC procedure was developed to monitor the formation of these hydrocarbons in γ-irradiated frog legs. Since frog legs contain large amounts of palmitic, stearic, oleic, and linoleic acids, the formation of the hydrocarbons (pentadecane, heptadecane, 8-heptadecene, and 6,9-heptadecadiene, respectively) from the decarboxylation of these fatty acids was monitored. The yields of these hydrocarbons were found to be linear with applied dose. A sample from a lot of imported frog legs that were believed to have been treated with ionizing radiation was also analyzed. The ESR technique, in conjunction with the GC data on the hydrocarbons, appears to be a useful approach for identifying and monitoring frog legs that have been treated with ionizing radiation.

  14. High Radiation Doses from Radiotherapy Measured by Electron Spin Resonance in Dental Enamel

    International Nuclear Information System (INIS)

    For radiotherapy, an error in the complicated treatment planning or treatment procedure is a possibility, however remote. Thus, in the present study electron spin resonance (ESR) in dental enamel was investigated for the first time as a means of retrospective dosimetry for validating applied radiotherapy doses to the head and neck regions. Total absorbed radiation doses measured by ESR in dental enamel were compared to the doses determined by treatment planning for 19 patients who received radiotherapy for intra-oral, pharyngeal or laryngeal malignancies, or total-body irradiation prior to bone marrow transplants (BMT). For the 15 tumour irradiations there was, within the framework of the tooth positions as presented, general agreement between the treatment planned and ESR dose determinations. There were, however, both significant and minor discrepancies. For the BMT patients there were major discrepancies for two of the four patients investigated. This study indicates that ESR in dental enamel may be useful as the only means of retrospective dosimetry for validating applied radiotherapy doses after treatment. However, further research must be carried out before this technique can be accepted as accurate and reliable. (author)

  15. Electron spin resonance and thermoluminescence in powder form of clear fused quartz: effects of grinding

    CERN Document Server

    Ranjbar, A H; Randle, K

    1999-01-01

    Clear fused quartz (CFQ) tubes were powdered either manually by using a mortar and pestle (for coarse production) or mechanically, using a micronising mill (for fine production). A high and multisignal electron spin resonance (ESR) background was found in the fine powder even after annealing it at 900 deg. C for 20 min. In the case of the coarse powder, the signal (ESR background) varied inversely with particle size and was quite high for particle sizes lower than 38 mu m. In a subsidiary experiment, using fine SiO sub 2 powder (99.8% pure, with the particle size of approx 0.007 mu m), manufactured by using flame hydrolysis, only a weak background signal was found. The sup 6 sup 0 Co gamma-ray irradiated powders (approx 22 Gy) were subjected to ESR analysis or thermoluminescence (TL) readout. The ESR intensity of the coarse powder varied directly with particle size. Thus, the intensity for a particle size of 20-38 mu m was very low and almost the same as the unirradiated intensity. In TL readout the results w...

  16. Gas chromatographic and electron spin resonance investigations of gamma-irradiated frog legs

    International Nuclear Information System (INIS)

    Several very sensitive techniques to measure radiation-induced products in frog legs were investigated. Presented here are results from the use of electron spin resonance (ESR) spectroscopy and capillary gas chromatography (GC) to measure radiolysis products in γ-irradiated frog legs. When bone is irradiated, a characteristic ESR signal develops and is easily measured. The intensity of the ESR signal is dose-dependent and stable for several months at room temperature. When triglycerides or fatty acids are irradiated, some of the major stable products formed are hydrocarbons with one less carbon than the precursor fatty acids. These hydrocarbons are formed as the result of the loss of CO2 during various free radical reactions. A capillary GC procedure was developed to monitor the formation of these hydrocarbons in γ-irradiated frog legs. Since frog legs contain large amounts of palmitic, stearic, oleic, and linoleic acids, the formation of the hydrocarbons (pentadecane, heptadecane, 8-heptadecene, and 6,9-heptadecadiene, respectively) from the decarboxylation of these fatty acids was monitored. The yields of these hydrocarbons were found to be linear with applied dose. A sample from a lot of imported frog legs that were believed to have been treated with ionizing radiation was also analyzed. The ESR technique, in conjunction with the GC data on the hydrocarbons, appears to be a useful approach for identifying and monitoring frog legs that have been treated with ionizing radiation. (author)

  17. The Simplest Resonant Spin-Flavour Solution to the Solar Neutrino Problem

    CERN Document Server

    Miranda, O G; Rashba, T I; Semikoz, V B; Valle, José W F

    2001-01-01

    We re-analyse the resonant spin-flavour (RSF) solutions to the solar neutrino problem in the framework of analytic solutions to the solar magneto-hydrodynamics (MHD) equations. By substantially eliminating the arbitrariness associated to the magnetic field profile due to both mathematical consistency and physical requirements we propose the simplest scheme (MHD-RSF, for short) for solar neutrino conversion using realistic static MHD solutions. Using such effective two-parameter scheme we perform the first global fit of the recent solar neutrino data, including event rates as well as zenith angle distributions and recoil electron spectra induced by solar neutrino interactions in Superkamiokande. We compare quantitatively our simplest MHD-RSF fit with vacuum oscillation (VAC) and MSW-type (SMA, LMA and LOW) solutions to the solar neutrino problem using a common well-calibrated theoretical calculation and fit procedure. We find our MHD-RSF fit to be somewhat better than those obtained for the favored neutrino os...

  18. Identification of γ-irradiated spices by electron spin resonance (ESR) spectrometry

    International Nuclear Information System (INIS)

    The electron spin resonance (ESR) spectrometry spectra of white (WP), black (BP) and red (Capsicum annuum L. var. frutescerns L., RP) peppers each had a principal signal with a g-value of 2.0043, and the intensities of the principal signals were increased not only by γ-irradiation but also by heating. Irradiated RP also showed a minor signal -30G from the principal one, and the intensity of the minor signal increased linearly with increasing dose from 10 to 50 kGy. Since the minor signal was observed in RP irradiated at 10 kGy and stored for one year, but did not appear either after heating or after exposure to this signal is unique to γ-irradiated RP and should therefore be useful for the identification of γ-irradiated spices of Capsicum genus, such as paprika and chili pepper. The computer simulation of the ESR spectra suggested that the minor signal should be assigned to methyl radical and the principal signal mainly to a combination of phenoxyl and peroxyl radicals. Such minor signals were found in γ-irradiated allspice and cinnamon among 10 kinds of other spices. (author)

  19. Ternary complexes of albumin-Mn(II)-bilirubin and Electron Spin Resonance studies of gallstones

    CERN Document Server

    Chikvaidze, E N; Kirikashvili, I N; Mamniashvili, G I

    2009-01-01

    The stability of albumin-bilirubin complex was investigated depending on pH of solution. It was shown that the stability of complex increases in presence of Mn(II) ions. It was also investigated the paramagnetic composition of gallstones by the electron spin resonance (ESR) method. It turned out that all investigated gallstones contain a free bilirubin radical-the stable product of its radical oxidation. Accordingly the paramagnetic composition gallstones could be divided on three main types: cholesterol, brown pigment and black pigment stones. ESR spectra of cholesterol stones is singlet with g=2.003 and splitting between components 1.0 mT. At the same time the brown gallstones, besides aforementioned signal contain the ESR spectrum which is characteristics for Mn(II) ion complexes with inorganic compounds and, finally, in the black pigment stones it was found out Fe(III) and Cu(II) complexes with organic compounds and a singlet of bilirubin free radical. It is supposed that crystallization centers of gallst...

  20. An electron spin resonance study of γ-ray irradiated pepper

    International Nuclear Information System (INIS)

    Using electron spin resonance (ESR) spectroscopy, we revealed four radical species in the irradiated pepper. The representative ESR spectrum of the pepper is composed of a sextet centered at g=2.0, a singlet at the same g-value, a singlet at g=4.0 and side peaks near g=2.0. The first one is attributable to a signal with hyperfine (hf) interactions of Mn2+ ion (hf constant=7.4 mT). The second one is due to an organic free radical that may be induced by the (γ-ray irradiation. The third one may be originated from Fe3+ ion in the non-hem proteins. Those three signals were found in the pepper sample before irradiation. The fourth signals were found at the symmetric position of the organic free radical, i.e., the second signal. The progressive saturation method of the ESR microwave power indicated quite different relaxation behaviors of those radicals. The method reflects four independent radical species in the irradiated pepper. Relaxation time for the singlet signal centered at g=2.0 revealed that the signal is due to the typical organic free radical. (author)

  1. Electron spin resonance characterization of radical components in irradiated black pepper skin and core

    International Nuclear Information System (INIS)

    Characteristics of free radical components of irradiated black pepper fruit (skin) and the pepper seed (core) were analyzed using electron spin resonance. A weak signal near g=2.005 was observed in black pepper before irradiation. Complex spectra near g=2.005 with three lines (the skin) or seven lines (the core) were observed in irradiated black pepper (both end line width; ca. 6.8 mT). The spectral intensities decreased considerably at 30 days after irradiation, and continued to decrease steadily thereafter. The spectra simulated on the basis of the content and the stability of radical components derived from plant constituents, including fiber, starch, polyphenol, mono- and disaccharide, were in good agreement with the observed spectra. Analysis showed that the signal intensities derived from fiber in the skin for an absorbed dose were higher, and the rates of decrease were lower, than that in the core. In particular, the cellulose radical component in the skin was highly stable. - Highlights: → We identified the radical components in irradiated black pepper skin and core. → The ESR spectra near g=2.005 with 3-7 lines were emerged after irradiation. → Spectra simulated basing on the content and the stability of radical from the plant constituents. → Cellulose radical component in black pepper skin was highly stable. → Single signal near g=2.005 was the most stable in black pepper core.

  2. Identification of irradiated wheat by germination test, DNA comet assay and electron spin resonance

    International Nuclear Information System (INIS)

    In several countries, there has been an increase in the use of radiation for food processing thus improving the quality and sanitary conditions, inhibiting pathogenic microorganisms, delaying the natural aging process and so extending product lifetime. The need to develop analytical methods to detect these irradiated products is also increasing. The goal of this research was to identify wheat irradiated using different radiation doses. Seeds were irradiated with a gamma 60Co source (Gammacell 220 GC) in the Centro de Energia Nuclear na Agricultura and the Instituto de Pesquisas Energeticas e Nucleares. Dose rate used were 1.6 and 5.8 kGy/h. Applied doses were 0.0, 0.10, 0.25, 0.50, 0.75, 1.0, and 2.0 kGy. After irradiation, seeds were analysed over a 6 month period. Three different detection methods were employed to determine how irradiation had modified the samples. Screening methods consisted of a germination test measuring the inhibition of shooting and rooting and analysis of DNA fragmentation. The method of electron spin resonance spectroscopy allowed a better dosimetric evaluation. These techniques make the identification of irradiated wheat with different doses possible

  3. Tooth enamel electron spin resonance dosimetry of people living in the area with lime tobacco custom

    International Nuclear Information System (INIS)

    Objective: To study the effect of the custom of long term chewing lime tobacco on human tooth enamel electron spin resonance (ESR) dosimetry. Methods: A total of 20 enamel samples from lingual parts of adults teeth collected in Bombay, India were obtained by mechanical method. Some enamel samples from Japanese adults were extracted and 10 mixed samples were prepared. Enamel samples were exposed to different doses of 60Co γ-rays several times, and ESR spectra were measured after exposure. Results: ESR background signals of 9 Bombay samples were found 1.5-3.3 times higher than those of Japanese mixed samples. The γ-ray dose responses of dosimetric signal with higher background level were a little lower, and the average sensitivity was (0.42±0.03) mGy, which was close to that of Japanese mixed samples. Conclusions: The average level of background signals of Bombay samples was much higher than that of other non-chewing tobacco area, which was possibly caused by tobacco area, which was possibly caused by tobacco lime, the main component in chewing tobacco productions, and it would help to explore its special influences on ESR, and improve dose reconstruction in accuracy. (authors)

  4. New sensitive agents for detecting singlet oxygen by electron spin resonance spectroscopy.

    Science.gov (United States)

    Igarashi, T; Sakurai, K; Oi, T; Obara, H; Ohya, H; Kamada, H

    1999-05-01

    Free radicals are well-established transient intermediates in chemical and biological processes. Singlet oxygen, though not a free radical, is also a fairly common reactive chemical species. It is rare that singlet oxygen is studied with the electron spin resonance (ESR) technique in biological systems, because there are few suitable detecting agents. We have recently researched some semiquinone radicals. Specifically, our focus has been on bipyrazole derivatives, which slowly convert to semiquinone radicals in DMSO solution in the presence of potassium tert-butoxide and oxygen. These bipyrazole derivatives are dimers of 3-methyl-1-phenyl-2-pyrazolin-5-one and have anti-ischemic activities and free radical scavenging properties. In this work, we synthesized a new bipyrazole derivative, 4,4'-bis(1p-carboxyphenyl-3-methyl-5-hydroxyl)-pyrazole, DRD156. The resulting semiquinone radical, formed by reaction with singlet oxygen, was characterized by ESR spectroscopy. DRD156 gave no ESR signals from hydroxyl radical, superoxide, and hydrogen peroxide. DRD156, though, gives an ESR response with hypochlorite. This agent, nevertheless, has a much higher ability to detect singlet oxygen than traditional agents with the ESR technique. PMID:10381208

  5. Identification of. gamma. -irradiated spices by electron spin resonance (ESR) spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Uchiyama, Sadao; Kawamura, Yoko; Saito, Yukio (National Inst. of Hygienic Sciences, Tokyo (Japan))

    1990-12-01

    The electron spin resonance (ESR) spectrometry spectra of white (WP), black (BP) and red (Capsicum annuum L. var. frutescerns L., RP) peppers each had a principal signal with a g-value of 2.0043, and the intensities of the principal signals were increased not only by {gamma}-irradiation but also by heating. Irradiated RP also showed a minor signal -30G from the principal one, and the intensity of the minor signal increased linearly with increasing dose from 10 to 50 kGy. Since the minor signal was observed in RP irradiated at 10 kGy and stored for one year, but did not appear either after heating or after exposure to this signal is unique to {gamma}-irradiated RP and should therefore be useful for the identification of {gamma}-irradiated spices of Capsicum genus, such as paprika and chili pepper. The computer simulation of the ESR spectra suggested that the minor signal should be assigned to methyl radical and the principal signal mainly to a combination of phenoxyl and peroxyl radicals. Such minor signals were found in {gamma}-irradiated allspice and cinnamon among 10 kinds of other spices. (author).

  6. Identification of irradiated wheat by germination test, DNA comet assay and electron spin resonance

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Adilson C. E-mail: acbarros@cena.usp.br; Freund, Maria Teresa L. E-mail: mtfreund@if.usp.br; Villavicencio, A.L.C.H. E-mail: villavic@net.ipen.br; Delincee, Henry E-mail: henry.delincee@bfe.uni-karlsruhe.de; Arthur, Valter E-mail: vaarthur@pira.cena.usp.br

    2002-03-01

    In several countries, there has been an increase in the use of radiation for food processing thus improving the quality and sanitary conditions, inhibiting pathogenic microorganisms, delaying the natural aging process and so extending product lifetime. The need to develop analytical methods to detect these irradiated products is also increasing. The goal of this research was to identify wheat irradiated using different radiation doses. Seeds were irradiated with a gamma {sup 60}Co source (Gammacell 220 GC) in the Centro de Energia Nuclear na Agricultura and the Instituto de Pesquisas Energeticas e Nucleares. Dose rate used were 1.6 and 5.8 kGy/h. Applied doses were 0.0, 0.10, 0.25, 0.50, 0.75, 1.0, and 2.0 kGy. After irradiation, seeds were analysed over a 6 month period. Three different detection methods were employed to determine how irradiation had modified the samples. Screening methods consisted of a germination test measuring the inhibition of shooting and rooting and analysis of DNA fragmentation. The method of electron spin resonance spectroscopy allowed a better dosimetric evaluation. These techniques make the identification of irradiated wheat with different doses possible.

  7. Antioxidant activity in hepatopancreas of the shrimp (Pleoticus muelleri) by electron paramagnetic spin resonance spectrometry.

    Science.gov (United States)

    Díaz, Ana C; Fernández Gimenez, Analía V; Mendiara, Sara N; Fenucci, Jorge L

    2004-05-19

    Free radical scavenging properties of hepatopancreas extracts of Pleoticus muelleri were evaluated by electron paramagnetic spin resonance spectrometry methods (EPR) against the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The present study was carried out to characterize different physiological stages of the shrimp under environmental and nutritional stress, evaluating the effect on growth, survival, and functional morphology of the hepatopancreas. Feeding trials were carried out on juveniles (1 g initial weight) held in aquaria. Each diet, with different concentrations of vitamins A and E, was tested in triplicate groups during 25 days. The control groups were fed with fresh squid mantle and with a vitamin-free diet. For all of the diets, the extracts exhibited strong DPPH radical scavenging activity, suggesting that the tissue is a powerful natural antioxidant. Individuals fed with different concentrations of vitamin E showed the strongest effect on the DPPH radicals, reducing the DPPH radicals to 50%, after an incubation period of 3 min. In contrast, the extracts of control animals, fed with squid mantle, had the weakest antioxidant activity (4%). These data indicated that the presence of vitamin E in the diet can provide immediate protection against free radicals. PMID:15137874

  8. ESR (Electronic Spin Resonance Spectroscopy) study of irradiated paper for biomedical material wrapping

    International Nuclear Information System (INIS)

    Ionising radiation treatments are used for sterilization, microbiological decontamination, disinfection, insect disinfestation and food preservation. This ionising radiation generates free radicals (FR) in matter, which can be detected by Electronic Spin Resonance Spectroscopy (ESR). For this work it had analysed different kind of irradiated package papers of syringes, surgical gloves and dressings by ESR. These were irradiated with doses between 20 and 35 kGy of gamma radiation (Cobalt 60). The processed samples were measured in a Bruker ECS 106 spectrometer. The obtained results were: 1-) The irritated samples showed a central peak and two satellites induced by the applied radiation; 2-) The non-irradiated samples did not show the characteristic satellite peaks of the irritated ones; 3-) A linear relationship between the signal heights per unit mass and the applied doses was found; and 4-) The signals were highly stable, with half-time values between 240 and 370 days for 20 and 30 kGy, permitting more than one year of monitoring proceedings. In conclusion, the ESR allows the detection, quantification and time monitoring processes of this kind of irradiated materials. (author)

  9. Comparison of defects in crystalline oxide semiconductor materials by electron spin resonance

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Tokiyoshi, E-mail: toki@rins.ryukoku.ac.jp; Kimura, Mutsumi [Department of Electronics and Informatics, Faculty of Science and Technology, Ryukoku University, 1-438, 1-5 Yokotani, Seta Oe-Cho, Otsu, Shiga 520-2194, Japan and Joint Research Center for Science and Technology, Ryukoku University, 1-5 Yokotani, Seta Oe-Cho, Otsu, Shiga 520-2194 (Japan)

    2015-03-15

    Defects in crystalline InGaZnO{sub 4} (IGZO) induced by plasma were investigated using electron spin resonance (ESR). Thermal stabilities and g factors of two ESR signals (A and B observed at g = 1.939 and 2.003, respectively) in IGZO were different from those of the ESR signals observed in component materials such as Ga{sub 2}O{sub 3} (signal observed at g = 1.969), In{sub 2}O{sub 3} (no signal), and ZnO (signal observed at g = 1.957). Signal A in IGZO increased upon annealing at 300 °C for 1 h, but decreased when annealing was continued for more than 2 h. On the other hand, signal B decreased upon annealing at 300 °C for 1 h. The ESR signal in ZnO decayed in accordance with a second-order decay model with a rate constant of 2.1 × 10{sup −4} s{sup −1}; however, this phenomenon was not observed in other materials. This difference might have been due to randomly formed IGZO lattices such as asymmetrical (Ga, Zn)O and In-O layers. Defects in signals A and B in IGZO were formed in trap states (at the deep level) and tail states, respectively.

  10. Electron spin resonance investigation of irradiated Si-SiO2

    International Nuclear Information System (INIS)

    The point defects of Pb and E' in two kinds of Si-SiO2 formed by different technological process, before and after irradiation with different dosage and bias field, have been examined using electron spin resonance (ESR). The experimental results show that there are Pb defects in both kinds of Si-SiO2 no matter whether they are irradiated, and the radiation of 60Co can generate more Pb defects in the Si-SiO2 systems. In the first kind of Si-SiO2 the E' defects can be observed after irradiation with positive bias field, while with free field these defects appear only when the irradiation dosage is as high as 50 kGy(Si). But there are not any E' in the second kind of Si-SiO2 even if they are irradiated. Besides, the ΔH(peak to peak) of Pb and E' in the ESR spectra indicates that Pb is referred to a slow relaxation defect but E' to a fast relaxation defect. Finally, the experimental results are qualitatively explained

  11. Estimation of the absorbed dose in gamma irradiated food containing bone by electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    The use of electron spin resonance (ESR) spectroscopy to accurately evaluate the absorbed dose to radiationprocessed bones (and thus meats) is examined. The exposure of foodstuffs containing bone to a dose of ionizing radiation results in the formation of long lived free radicals which give rise to characteristics ESR signals. The yield of radicals was found to be proportional to absorbed dose. Additive re-irradiation of previously irradiated bone was used to estimate the absorbed dose in the irradiated chicken bone. Simple non-linear rational equation was found to fit to the data and yields good dose estimates for irradiated bone in the range of doses (1.0 - 5.0 kGy). Decay of the ESR signal intensity was monitored at different dose levels (2.0 and 7.0 kGy) up to 22 days. The absorbed dose in irradiated chicken (2.Om 3.0 and 6.0 kGy) was assessed at 2, 6 and 12 days after irradiation. Relatively good results were obtained when measurements were made within the following days (up to 12 days) after irradiation. The ability of the dose additive method to provide accurate dose assessments is tested here

  12. Cyclic voltammetry, spectroelectrochemistry and electron spin resonance as combined tools to study thymoquinone in aprotic medium

    International Nuclear Information System (INIS)

    Nigella sativa has been used for centuries as a natural remedy for a number of chronic and age-related diseases. Thymoquinone (TQ), the main constituent of its extracts, has recently received particular attention and has been tested for its antioxidant, anti-inflammatory and anticancer properties. To further investigate the mechanisms involved in the biological activities of this natural quinone and, among these, in its antioxidant properties, the redox-system of TQ and its interaction with superoxide was studied in aprotic medium by cyclic voltammetry, spectroelectrochemistry and Electron Spin Resonance (ESR). The electrochemical behavior of dithymoquinone (DTQ), the photodimer of TQ, was also studied in the same medium. Experimental data evidenced the formation of the radical anion TQ·− by cathodic reduction of TQ at potential values very close to coenzymes Q ones, by electron transfer (ET) between TQ and superoxide, as KO2 or electrogenerated, by chemical comproportionation between TQ and the dianion TQ−− and by fast cleavage of the electrogenerated radical anion DTQ·−. Spectroelectrochemical data evidenced that TQ·−, in the presence of TQ, evolves to the hydroquinone monoanion TQH−, suggesting that an H-atom transfer (HT) may occur, likely from the isopropylic side-chain of TQ to TQ·− The H-atom donating ability of TQ may be also supported by Bond Dissociation Energy values and ESR data.

  13. Optical and electrical control of spin polarization of two-dimensional hole gases in p-type resonant tunnelling devices

    International Nuclear Information System (INIS)

    In this work, we have investigated the spin polarization from two-dimensional hole gases (2DHG) formed in p–i–p GaAs/AlAs resonant tunnelling diodes (RTDs) under magnetic field parallel to the tunnel current. We have observed that the polarization degree from the quantum well (QW) and the 2DHG formed at the accumulation layer is highly voltage and light sensitive and exhibits a clear sign inversion. Our results indicate that the voltage dependence of the QW polarization degree is mainly due to an efficient hole-resonant tunnelling process through spin states of the QW. On the other hand, the voltage dependence of the 2DHG polarization degree seems to be dependent on the hole density which is controlled by the applied voltage across the RTDs. (paper)

  14. Effects of Be acceptors on the spin polarization of carriers in p-i-n resonant tunneling diodes

    International Nuclear Information System (INIS)

    In this paper, we have investigated the effect of Be acceptors on the electroluminescence and the spin polarization in GaAs/AlAs p-i-n resonant tunneling diodes. The quantum well emission comprise two main lines separated by ∼20 meV attributed to excitonic and Be-related transitions, which intensities show remarkably abrupt variations at critical voltages, particularly at the electron resonant peak where it shows a high-frequency bistability. The circular-polarization degree of the quantum-well electroluminescence also shows strong and abrupt variations at the critical bias voltages and it attains relatively large values (of ∼−75% at 15 T). These effects may be explored to design novel devices for spintronic applications such as a high-frequency spin-oscillators

  15. Effects of Be acceptors on the spin polarization of carriers in p-i-n resonant tunneling diodes

    Science.gov (United States)

    Awan, I. T.; Galeti, H. V. A.; Galvão Gobato, Y.; Brasil, M. J. S. P.; Taylor, D.; Henini, M.

    2014-08-01

    In this paper, we have investigated the effect of Be acceptors on the electroluminescence and the spin polarization in GaAs/AlAs p-i-n resonant tunneling diodes. The quantum well emission comprise two main lines separated by ˜20 meV attributed to excitonic and Be-related transitions, which intensities show remarkably abrupt variations at critical voltages, particularly at the electron resonant peak where it shows a high-frequency bistability. The circular-polarization degree of the quantum-well electroluminescence also shows strong and abrupt variations at the critical bias voltages and it attains relatively large values (of ˜-75% at 15 T). These effects may be explored to design novel devices for spintronic applications such as a high-frequency spin-oscillators.

  16. Spatial arrangement of rhodopsin in retinal rod outer segment membranes studied by spin-labeling and pulsed electron double resonance

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Satoshi [Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Department of Space and Earth Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Hara, Hideyuki [Bruker Biospin, Yokohama, Kanagawa 215-0022 (Japan); Tokunaga, Fumio [Department of Space and Earth Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Arata, Toshiaki, E-mail: arata@bio.sci.osaka-u.ac.jp [Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Department of Space and Earth Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Use of spin labeling and PELDOR to measure inter-rhodopsin distance in ROS. Black-Right-Pointing-Pointer Strong decay of PELDOR signal indicated a high density (mM range) of rhodopsin. Black-Right-Pointing-Pointer The decay was modeled by rhodopsin monomers dispersed in a planar membrane. -- Abstract: We have determined the spatial arrangement of rhodopsin in the retinal rod outer segment (ROS) membrane by measuring the distances between rhodopsin molecules in which native cysteines were spin-labeled at {approx}1.0 mol/mol rhodopsin. The echo modulation decay of pulsed electron double resonance (PELDOR) from spin-labeled ROS curved slightly with strong background decay. This indicated that the rhodopsin was densely packed in the retina and that the rhodopsin molecules were not aligned well. The curve was simulated by a model in which rhodopsin is distributed randomly as monomers in a planar membrane.

  17. Density functional theory (DFT) calculations of the proton nuclear magnetic resonance (NMR) spin-Hamiltonian parameters for serine

    International Nuclear Information System (INIS)

    1H nuclear magnetic resonance spin-Hamiltonian parameters: chemical shifts δ and indirect spin–spin coupling constants J, have been calculated for serine, a brain metabolite. Serine molecules in the gas-phase as well as in solution in water have been investigated using density functional theory. Solvent and conformer effects as well as zero-point vibrational corrections have been taken into account. For the non-vibrating molecule, the best agreement is obtained when solvent and conformer effects are included. Zero-point vibrational corrections improve the agreement with experimental values, leading to a root mean square deviation of 0.05 ppm for chemical shifts and 0.7 Hz for spin–spin coupling constants

  18. l-Tryptophan Radical Cation Electron Spin Resonance Studies: Connecting Solution-derived Hyperfine Coupling Constants with Protein Spectral Interpretations

    OpenAIRE

    Connor, Henry D.; Sturgeon, Bradley E.; Mottley, Carolyn; Sipe, Herbert J.; Mason, Ronald P.

    2008-01-01

    Fast-flow electron spin resonance (ESR) spectroscopy has been used to detect a free radical formed from the reaction of l-tryptophan with Ce4+ in an acidic aqueous environment. Computer simulations of the ESR spectra from l-tryptophan and several isotopically modified forms strongly support the conclusion that the l-tryptophan radical cation has been detected by ESR for the first time. The hyperfine coupling constants (HFCs) determined from the well-resolved isotropic ESR spectra support expe...

  19. Electron Spin Resonance study of charge trapping in α-ZnMoO.sub.4./sub. single crystal scintillator

    Czech Academy of Sciences Publication Activity Database

    Buryi, Maksym; Spassky, D.A.; Hybler, Jiří; Laguta, Valentyn; Nikl, Martin

    2015-01-01

    Roč. 47, Sep (2015), 244-250. ISSN 0925-3467 R&D Projects: GA MŠk LO1409; GA MŠk(CZ) LM2011029; GA ČR GAP204/12/0805 Institutional support: RVO:68378271 Keywords : Electron Spin Resonance * scintillator * charge traps * zinc molybdate Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.981, year: 2014

  20. Voxel-level comparison of arterial spin-labeled perfusion magnetic resonance imaging in adolescents with internet gaming addiction

    OpenAIRE

    Feng, Qi; Chen, Xue; Sun, Jinhua; Zhou, Yan; Sun, Yawen; Ding, Weina; Zhang, Yong; Zhuang, Zhiguo; Xu, Jianrong; Du, Yasong

    2013-01-01

    Background Although recent studies have clearly demonstrated functional and structural abnormalities in adolescents with internet gaming addiction (IGA), less is known about how IGA affects perfusion in the human brain. We used pseudocontinuous arterial spin-labeling (ASL) perfusion functional magnetic resonance imaging (fMRI) to measure the effects of IGA on resting brain functions by comparing resting cerebral blood flow in adolescents with IGA and normal subjects. Methods Fifteen adolescen...

  1. Long-lived frequency shifts observed in a magnetic resonance force microscope experiment following microwave irradiation of a nitroxide spin probe

    International Nuclear Information System (INIS)

    We introduce a spin-modulation protocol for force-gradient detection of magnetic resonance that enables the real-time readout of longitudinal magnetization in an electron spin resonance experiment involving fast-relaxing spins. We applied this method to observe a prompt change in longitudinal magnetization following the microwave irradiation of a nitroxide-doped perdeuterated polystyrene film having an electron spin-lattice relaxation time of T1∼1ms. The protocol allowed us to discover a large, long-lived cantilever frequency shift. Based on its magnitude, lifetime, and field dependence, we tentatively attribute this persistent signal to deuteron spin magnetization created via transfer of polarization from nitroxide spins.

  2. Dynamic nuclear polarization enhanced nuclear magnetic resonance and electron spin resonance studies of hydration and local water dynamics in micelle and vesicle assemblies.

    Science.gov (United States)

    McCarney, Evan R; Armstrong, Brandon D; Kausik, Ravinath; Han, Songi

    2008-09-16

    We present a unique analysis tool for the selective detection of local water inside soft molecular assemblies (hydrophobic cores, vesicular bilayers, and micellar structures) suspended in bulk water. Through the use of dynamic nuclear polarization (DNP), the (1)H NMR signal of water is amplified, as it interacts with stable radicals that possess approximately 658 times higher spin polarization. We utilized stable nitroxide radicals covalently attached along the hydrophobic tail of stearic acid molecules that incorporate themselves into surfactant-based micelle or vesicle structures. Here, we present a study of local water content and fluid viscosity inside oleate micelles and vesicles and Triton X-100 micelles to serve as model systems for soft molecular assemblies. This approach is unique because the amplification of the NMR signal is performed in bulk solution and under ambient conditions with site-specific spin labels that only detect the water that is directly interacting with the localized spin labels. Continuous wave (cw) electron spin resonance (ESR) analysis provides rotational dynamics of the spin-labeled molecular chain segments and local polarity parameters that can be related to hydration properties, whereas we show that DNP-enhanced (1)H NMR analysis of fluid samples directly provides translational water dynamics and permeability of the local environment probed by the spin label. Our technique therefore has the potential to become a powerful analysis tool, complementary to cw ESR, to study hydration characteristics of surfactant assemblies, lipid bilayers, or protein aggregates, where water dynamics is a key parameter of their structure and function. In this study, we find that there is significant penetration of water inside the oleate micelles with a higher average local water viscosity (approximately 1.8 cP) than in bulk water, and Triton X-100 micelles and oleate vesicle bilayers mostly exclude water while allowing for considerable surfactant chain

  3. Two-loop QCD Correction to Massive Spin-2 Resonance $ \\to q ~ \\bar{q} ~ g $

    CERN Document Server

    Ahmed, Taushif; Mathews, Prakash; Rana, Narayan; Ravindran, V

    2016-01-01

    Two-loop QCD correction to massive spin-2 Graviton decaying to $q ~ + ~ \\bar{q}~ + ~g$ is presented considering a generic universal spin-2 coupling to the SM through the conserved energy-momentum tensor. Such a massive spin-2 particle can arise in extra-dimensional models. The ultraviolet and infrared structure of the QCD amplitudes are studied. In dimensional regularisation, the infrared pole structure is in agreement with Catani's proposal, confirming the universal factorization property of QCD amplitudes, even with the spin-2 tensorial coupling. This computation now completes the full two-loop QCD corrections for the production of a spin-2 in association with a jet.

  4. All-optical thermometry and the thermal properties of the optically detected spin resonances of the NV center in nano-diamond

    OpenAIRE

    Plakhotnik, Taras; Doherty, Marcus W.; Jared H. Cole; Chapman, Robert; Manson, Neil B.

    2015-01-01

    The negatively-charged nitrogen-vacancy (NV) center in diamond is at the frontier of quantum nano-metrology and bio-sensing. Recent attention has focused on the application of high-sensitivity thermometry using the spin resonances of NV centers in nano-diamond to sub-cellular biological and biomedical research. Here, we report a comprehensive investigation of the thermal properties of the center's spin resonances and demonstrate an alternate all-optical NV thermometry technique that exploits ...

  5. Electron spin resonance investigaton of semiconductor materials for application in thin-film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Lihong

    2012-07-01

    In the present work, hydrogenated silicon and its alloys silicon carbide and silicon oxide have been investigated using electron spin resonance (ESR). The microstructure of these materials ranges from highly crystalline to amorphous. The correlation between the paramagnetic defects, microstructure, optical and electrical properties has been discussed. Correspondingly, these properties were characterized by the spin density (N{sub S}), g-value and the lineshape of ESR spectra, Infrared (I{sup IR}{sub C}) and/or Raman crystallinity (I{sup RS}{sub C}) as well as optical absorption and electrical dark conductivity ({sigma}{sub D}). 1. As the light absorber, Si layers essentially should have low defect density and good stability against light exposure. The spin density (N{sub S}) measured by ESR is often used as a measure for the paramagnetic defect density (N{sub D}) in the material. However, ESR sample preparation procedures can potentially cause discrepancy between N{sub S} and N{sub D}. Using Mo-foil, Al-foil and ZnO:Al-covered glass as sacrificial substrates, {mu}c-Si:H and a-Si:H films were deposited by plasma-enhanced chemical vapor deposition (PECVD), and ESR powder samples have been prepared with corresponding procedures. Possible preparation-related metastability and instability effects have been investigated in terms of substrate dependence, HCl-etching and atmosphere exposure. A sequence of 'preparation - annealing - air-exposure - annealing' has been designed to investigate the metastability and instability effects. N{sub S} after post-preparation air exposure is higher than in the annealed states, especially for the highly crystalline {mu}c-Si:H material the discrepancy reached one order of magnitude. Low temperature ESR measurements at 40 K indicated that atmospheric exposure leads to a redistribution of the defect states which in turn influence the evaluated N{sub S}. In annealed conditions the samples tend to have lower N{sub S} presumably due

  6. Coupled Magnetic Resonator Optical Waveguides - mimicking spin waves in coupled metamaterials

    CERN Document Server

    Liu, Hui

    2013-01-01

    Optical resonators are important devices that control the properties of light and manipulate light-matter interaction. Various optical resonators are designed and fabricated using different techniques. For example, in coupled resonator optical waveguides, light energy is transported to other resonators through near-field coupling. In recent years, magnetic optical resonators based on LC resonance have been realized in several metallic microstructures. Such devices possess stronger local resonance and lower radiation loss compared with electric optical resonators. This study provides an overall introduction on the latest progress in coupled magnetic resonator optical waveguide (CMROW). Various waveguides composed of different magnetic resonators are presented and Lagrangian formalism is used to describe the CMROW. Moreover, several interesting properties of CMROW, such as abnormal dispersions and slow light effects, are discussed and CMROW applications in nonlinear and quantum optics are shown. Future novel na...

  7. A study on the characteristics of enamel to electron spin resonance spectrum for retrospective dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Dae Seok; Lee, Kun Jai [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    2003-10-01

    Electron Spin Resonance (ESR) spectroscopy is one of the methods applicable to retrospective dosimetry. The retrospective dosimetry is a part of dose reconstruction for estimation of exposed dose occurred years before the estimation. A tooth can be separated as enamel, dentine and cementum. Among the three parts, enamel is known as to show the best sensitivity to the absorbed dose and is most widely used. Since the later 80s, ESR dosimetry with tooth enamel has been studied and applied for the retrospective dosimetry. There are some factors affecting the sensitivity of enamel to absorbed dose. One of the factors is a size of enamel. Grain size of the 1.0mm{approx}0.1mm range is commonly used and 0.6mm{approx}0.25mm is recommended in other study. But the sensitivity can be varied by the grain size. In this study, the granular effect of enamel to the sensitivity is examined for application to retrospective dosimetry. In the enamel separation, to minimize the physically induced ESR spectrum, only chemical separation method was used. Separated enamels were divided by their size. The sizes of each sample is 1.0mm{approx}0.71mm, 0.5mm{approx}0.3mm, and below 0.1mm, respectively. All enamel samples show ESR spectrum related to the absorbed dose and the ESR spectrum shows linearity to the absorbed dose. The sensitivities are similar for each sample. But the enamel of size below 0.1mm shows poor characteristics relative to other enamel size. So, it is not recommended to use enamel samples below 0.1mm.

  8. Electron spin resonance. Part two: a diagnostic method in the environmental sciences.

    Science.gov (United States)

    Rhodes, Christopher J

    2011-01-01

    A review is presented of some of the ways in which electron spin resonance (ESR) spectroscopy may be useful to investigate systems of relevance to the environmental sciences. Specifically considered are: quantititave ESR, photocatalysis for pollution control; sorption and mobility of molecules in zeolites; free radicals produced by mechanical action and by shock waves from explosives; measurement of peroxyl radicals and nitrate radicals in air; determination of particulate matter polyaromatic hydrocarbons (PAH), soot and black carbon in air; estimation of nitrate and nitrite in vegetables and fruit; lipid-peroxidation by solid particles (silica, asbestos, coal dust); ESR of soils and other biogenic substances: formation of soil organic matter carbon capture and sequestration (CCS) and no-till farming; detection of reactive oxygen species in the photosynthetic apparatus of higher plants under light stress; molecular mobility and intracellular glasses in seeds and pollen; molecular mobility in dry cotton; characterisation of the surface of carbon black used for chromatography; ESR dating for archaeology and determining seawater levels; measurement of the quality of tea-leaves by ESR; green-catalysts and catalytic media; studies of petroleum (crude oil); fuels; methane hydrate; fuel cells; photovoltaics; source rocks; kerogen; carbonaceous chondrites to find an ESR-based marker for extraterrestrial origin; samples from the Moon taken on the Apollo 11 and Apollo 12 missions to understand space-weathering; ESR studies of organic matter in regard to oil and gas formation in the North Sea; solvation by ionic liquids as green solvents, ESR in food and nutraceutical research. PMID:22308901

  9. Magnetic resonance urography in pediatrics: utilization of ultrafast single-shot spin echo sequences

    International Nuclear Information System (INIS)

    To determine the value of magnetic resonance urography (MRU) using ultrafast single-shot (SS) rapid acquisition with relaxation enhancement (RARE) and half-Fourier (HF) SS-RARE (SS-HF-RARE or HASTE) in the evaluation of congenital urinary tract anomalies in pediatric patients, and their possible application as alternatives to intravenous urography (IVU). Eighteen children (11 boys and 7 girls) aged 2 months to 15 years (mean: 5 years) with a total of 19 congenital urinary tract anomalies were studies by MU using SS-RARE and HASTE sequences in a 1 Tesla scanner. All the patients had previously been studies by ultrasound (US) and IVU. Twelve patients required anesthesia. The images were acquired by means of a HASTE sequence with multisection technique (TR, infinite; TEef, 87 msec; echo train, 128; interval between echoes, 10.9 msec; total acquisition time, 13 sections/12 seconds), and SS-RARE (TR, infinite; TEef, 1.100 msec; echo train, 240, and acquisition time, 7 seconds). Four radiologists evaluated the images independently; two who reviewed the IV images in consensus and two who reviewed the MRU images in consensus. The images were evaluated to assess the dilatation of the urinary tract and their utility in detecting the level and cause of the obstruction. MRU images revealed the urinary tract dilation, the level of the obstruction and the type of anomaly in 18 patients (100%), while IVU provided this information in only 10 [ sensitivity, 53%, 95% confidence interval (29%, 76%)]. The mean time required for MRU was 20 minutes (range: 7 to 30 minutes), while that of IVU was 1,242 minutes (range: 45 to 1,440 minutes). MRU using ultrafast single-short spin echo sequences is a rapid and effective technique that permits and excellent evaluation of congenital urinary tract anomalies in pediatric patients and does not require the administration of contrast media or ionizing radiation. (Author) 10 refs

  10. Use of electron spin resonance technique for identifying of irradiated foods

    International Nuclear Information System (INIS)

    The present investigation was carried out to establish the electron spin resonance (ESR) technique for identifying of some irradiated foodstuffs, i.e. dried fruits (fig and raisin), nuts (almond and pistachio) and spices (fennel and thyme). Gamma rays were used as follows: 0, 1, 3 and 5 kGy were given for dried fruits, while 0, 2, 4 and 6 kGy were given for nuts. In addition, 0, 5, 10 and 15 kGy were given for spices. All treatments were stored at room temperature (25±2 degree C) for six months to study the possibility of detecting its irradiation treatment by ESR spectroscopy. The obtained results indicated that ESR signal intensities of all irradiated samples were markedly increased correspondingly with irradiation dose as a result of free radicals generated by gamma irradiation. So, all irradiated samples under investigation could be differentiated from unirradiated ones immediately after irradiation treatment. The decay that occur in free radicals which responsible of ESR signals during storage periods at ambient temperature showed a significant minimize in ESR signal intensities of irradiated samples. Therefore, after six months of ambient storage the detection was easily possible for irradiated dried fig with dose ≥ 3 kGy and for all irradiated raisin and pistachio (shell). Also, it was possible for irradiated fennel with dose ≥ 10 kGy and for irradiated thyme with dose ≥15 kGy. In contrast, the identification of all irradiated samples of almond (shell as well as edible part) and pistachio (edible part) was impossible after six months of ambient storage.

  11. Applications of electron spin resonance to some problems of radiation chemistry

    International Nuclear Information System (INIS)

    The electron spin resonance (E.S.R.) spectra of gamma irradiated polar organic glasses, at 77 K, shows a single line centered at g ∼ 2, attributed to solvated electrons. The radicals produced on scavenging this species by electron acceptors, such as aromatic hydrocarbons, nitro-compounds and azines have been studied by E.S.R. In most cases, the radicals from these solutes, the spectra of which are observed after elimination by warming of the radicals from the matrices, are produced by protonation of the anions formed by scavenging of electrons at 77 K. Thus, in the case of glassy solutions of nitro-compounds, the radicals R NO2H are formed. They are characterized by aN = 15 G (nitrobenzene) or aN = 28 G (nitro-alkane). These radicals are also generated by U.V, photolysis at room temperature of solutions of nitro-compounds in alcohols and are shown to be the precursors of nitroxide radicals R - N - R (with N - O) observed simultaneously. Gamma irradiation of solutions of pyridine and of the three diazines, in alcohol glasses at 77 K, produces the radical formed by hydrogen addition to these compounds. The value of the coupling constant of the additional proton (7-10 G) indicates that it is bound to a nitrogen in the sp2 hydridation state. One has shown, taking pyridine as an example, that the addition to a carbon gives a much greater value of the coupling constant, of the order of 50-60 G. (author)

  12. Geochemistry and electron spin resonance of hydrothermal dickite (Nowa Ruda, Lower Silesia, Poland): vanadium and chromium

    Science.gov (United States)

    Premović, Pavle I.; Ciesielczuk, Justyna; Bzowska, Grażyna; Đorđević, Miloš G.

    2012-06-01

    Geochemical analyses for trace V and Cr have been done on a representative sample of a typical hydrothermal dickite/kaolinite filling vein at Nowa Ruda. The mineralogy of the sample is comparatively simple, dickite being the principal component (ca. 91 % of the total sample). Geochemical fractionation and inductively coupled plasma-optical emission spectrometry (ICP-OES) indicate that most (> 90 % of total metal) of the V and Cr reside in the dickite. Electron Spin Resonance (ESR) shows that most (> 70 %) of the V in the dickite structure is in the form of vanadyl (VO2+) ions. A high concentration of Cr3+ is also detected in this structure by ESR. The combination of geochemical and spectroscopic tools applied to VO2+ and Cr3+ allow one to specify the Eh (> 0.4 V, highly oxidizing) and pH (≤4.0, highly acidic) of the solution during the formation of dickite from the Nowa Ruda Basin. Substantial proportions of the V and Cr (as well as VO2+ and Cr3+) in the dickite structure were probably contained in an original hydrothermal acid water. We suggest that hot hydrothermal waters leached the surrounding varieties of gabbroids enriched in V and Cr for the dickite-forming solution. The results of this work have shown V and Cr are potentially reliable indicators for geochemical characterization of the physicochemical conditions of their formation. The bulk-rock V/Cr ratio in hydrothermal dickites and kaolinites from Nowa Ruda, Sonoma (California, USA), Cigar Lake (Saskatchewan, Canada) and Teslić (Bosnia and Hercegovina) is also briefly explored here as a potential tracer of redox state during their formation.

  13. Electron spin resonance detection of radiosterilization of pharmaceuticals: application to four nitrofurans.

    Science.gov (United States)

    Basly, J P; Basly, I; Bernard, M

    1998-08-01

    The detection and dosimetry of radiosterilization of pharmaceuticals is a growing concern to numerous government regulatory agencies worldwide. In the absence of suitable detection methods, attention was focused on electron spin resonance (ESR) spectrometry. This paper reports experimental data on ESR dosimetry of irradiated nitrofurans (nitrofurantoin, nifuroxazide, nifurzide and nifurtoinol). Whereas the ESR spectrum of a non-irradiated sample shows no signal, a signal, that is dependent on the irradiation dose is observed with irradiated samples. The number of free radicals was calculated by comparing the second integral from radiosterilized samples and a Bruker strong pitch reference; the values were in the range 1.1 x 10(18)-1.5 x 10(19) radicals mol-1 (G = 0.003-0.03). In addition to qualitative detection, ESR spectrometry can be used for dose determination. When a bi-exponential function is applied to the variation of the peak-to-peak amplitude versus dose, the function correlates well with the data. However, an exponential function, easier to use than a bi-exponential function, will probably be sufficient for dose determination by retrospective dosimetry. Decay of radicals upon storage was modelled using a bi-exponential function. From this, the time limit from the irradiation (25 kGy) for identification of irradiated nitrofurans by ESR can be evaluated. With regard to the commercial aspects of drugs, radicals should be detected up to 2 years after irradiation. The kinetic decrease makes discrimination between irradiated and non-irradiated nitrofurans possible even after storage for up to 2 years, except for nifurtoinol. PMID:10071389

  14. Electron doping evolution of the neutron spin resonance in NaFe1 -xCoxAs

    Science.gov (United States)

    Zhang, Chenglin; Lv, Weicheng; Tan, Guotai; Song, Yu; Carr, Scott V.; Chi, Songxue; Matsuda, M.; Christianson, A. D.; Fernandez-Baca, J. A.; Harriger, L. W.; Dai, Pengcheng

    2016-05-01

    Neutron spin resonance, a collective magnetic excitation coupled to superconductivity, is one of the most prominent features shared by a broad family of unconventional superconductors including copper oxides, iron pnictides, and heavy fermions. In this paper, we study the doping evolution of the resonances in NaFe1 -xCoxAs covering the entire superconducting dome. For the underdoped compositions, two resonance modes coexist. As doping increases, the low-energy resonance gradually loses its spectral weight to the high-energy one but remains at the same energy. By contrast, in the overdoped regime we only find one single resonance, which acquires a broader width in both energy and momentum but retains approximately the same peak position even when Tc drops by nearly a half compared to optimal doping. These results suggest that the energy of the resonance in electron overdoped NaFe1 -xCoxAs is neither simply proportional to Tc nor the superconducting gap but is controlled by the multiorbital character of the system and doped impurity scattering effect.

  15. Transformation of Symmetrization Order to Nuclear-Spin Magnetization by Chemical Reaction and Nuclear Magnetic Resonance

    OpenAIRE

    Bowers, C. Russell; Weitekamp, Daniel P.

    1986-01-01

    A method of obtaining very large nuclear-spin polarizations is proposed and illustrated by density-operator calculations. The prediction is that chemical reaction and rf irradiation can convert the scalar parahydrogen state into polarization of order unity on the nuclear spins of the products of molecular-hydrogen addition reactions. A means of extending the resultant sensitivity enhancement to other spins is proposed in which the transfer of order occurs through population differences not as...

  16. Spin resonance transport properties of a single Au atom in S–Au–S junction and Au–Au–Au junction

    Science.gov (United States)

    Fangyuan, Wang; Guiqin, Li

    2016-07-01

    The spin transport properties of S–Au–S junction and Au–Au–Au junction between Au nanowires are investigated with density functional theory and the non-equilibrium Green's function. We mainly focus on the spin resonance transport properties of the center Au atom. The breaking of chemical bonds between anchor atoms and center Au atom significantly influences their spin transmission characteristics. We find the 0.8 eV orbital energy shift between anchor S atoms and the center Au atom can well protect the spin state stored in the S–Au–S junction and efficiently extract its spin state to the current by spin resonance mechanism, while the spin interaction of itinerant electrons and the valence electron of the center Au atom in the Au–Au–Au junction can extract the current spin information into the center Au atom. Fermi energy drift and bias-dependent spin filtering properties of the Au–Au–Au junction may transform information between distance, bias, and electron spin. Those unique properties make them potential candidates for a logical nanocircuit. Project supported by the National Basic Research Program of China (Grants No. 2011CB921602) and the National Natural Science Foundation of China (Grants No. 20121318158).

  17. Aluminum doped silicon carbide thin films prepared by hot-wire CVD: Investigation of defects with electron spin resonance

    International Nuclear Information System (INIS)

    Al-doped p-type μc-SiC:H is prepared in a wide range of HWCVD preparation parameters like Al-doping ratio, deposition pressure, substrate and filament temperatures. We investigate the structural and electrical properties, and focus on identification of paramagnetic defect states by electron spin resonance (ESR). Nominally undoped μc-SiC:H is of a high n-type conductivity (σD = 10-6-10-1 S/cm) and shows a narrow central ESR line (g ∼ 2.003, peak-to-peak linewidth ΔHpp ∼ 4 G) with two pairs of satellites and a spin density NS = 1019 cm-3. Al-doping results in the compensation of dark conductivity to as low as σD = 10-11 S/cm and at higher doping concentrations to effective p-type material. Increase of Al-doping results in reduction of crystallinity (ICIR), ESR line shifts to g ∼ 2.01 and becomes as broad as ΔHpp ∼ 30 G, not unlike to the resonance of singly occupied paramagnetic valence band tail states in a-Si:H. ESR spectrum of highly crystalline Al-doped μc-SiC:H however has a g-value very close to undoped μc-SiC:H. Electron spin density in compensated material decreases to 5 x 1017 cm-3 before it increases again for the highly doped material.

  18. Backbone Dynamics of Alamethicin Bound to Lipid Membranes: Spin-Echo Electron Paramagnetic Resonance of TOAC-Spin Labels

    Science.gov (United States)

    Bartucci, Rosa; Guzzi, Rita; De Zotti, Marta; Toniolo, Claudio; Sportelli, Luigi; Marsh, Derek

    2008-01-01

    Alamethicin F50/5 is a hydrophobic peptide that is devoid of charged residues and that induces voltage-dependent ion channels in lipid membranes. The peptide backbone is likely to be involved in the ion conduction pathway. Electron spin-echo spectroscopy of alamethicin F50/5 analogs in which a selected Aib residue (at position n = 1, 8, or 16) is replaced by the TOAC amino-acid spin label was used to study torsional dynamics of the peptide backbone in association with phosphatidylcholine bilayer membranes. Rapid librational motions of limited angular amplitude were observed at each of the three TOAC sites by recording echo-detected spectra as a function of echo delay time, 2τ. Simulation of the time-resolved spectra, combined with conventional EPR measurements of the librational amplitude, shows that torsional fluctuations of the peptide backbone take place on the subnanosecond to nanosecond timescale, with little temperature dependence. Associated fluctuations in polar fields from the peptide could facilitate ion permeation. PMID:18096632

  19. Resonantly enhanced spin-lattice relaxation of Mn2 + ions in diluted magnetic (Zn,Mn)Se/(Zn,Be)Se quantum wells

    Science.gov (United States)

    Debus, J.; Ivanov, V. Yu.; Ryabchenko, S. M.; Yakovlev, D. R.; Maksimov, A. A.; Semenov, Yu. G.; Braukmann, D.; Rautert, J.; Löw, U.; Godlewski, M.; Waag, A.; Bayer, M.

    2016-05-01

    The dynamics of spin-lattice relaxation in the magnetic Mn2 + ion system of (Zn,Mn)Se/(Zn,Be)Se quantum-well structures are studied using optical methods. Pronounced cusps are found in the giant Zeeman shift of the quantum-well exciton photoluminescence at specific magnetic fields below 10 T, when the Mn spin system is heated by photogenerated carriers. The spin-lattice relaxation time of the Mn ions is resonantly accelerated at the cusp magnetic fields. Our theoretical analysis demonstrates that a cusp occurs at a spin-level mixing of single Mn2 + ions and a quick-relaxing cluster of nearest-neighbor Mn ions, which can be described as intrinsic cross-relaxation resonance within the Mn spin system.

  20. Spin Diffusion in Trapped Clouds of Cold Atoms with Resonant Interactions

    DEFF Research Database (Denmark)

    Bruun, Georg Morten; Pethick, C. J.

    2011-01-01

    We show that puzzling recent experimental results on spin diffusion in a strongly interacting atomic gas may be understood in terms of the predicted spin diffusion coefficient for a generic strongly interacting system. Three important features play a central role: (a) Fick’s law for diffusion must...

  1. Nuclear magnetic resonance in solids: evolution of spin temperature under multipulse irradiation and high symmetry molecular motions

    International Nuclear Information System (INIS)

    In a first part, autocorrelation functions are calculated taking into account the symmetry of molecular motions by group theoretical techniques. This very general calculation method is then used to evaluate the NMR spin-lattice relaxation times T1 and T1p as a function of the relative orientations of the magnetic field, the crystal and the rotation axis, in particular for cyclic, dihedral and cubic groups. Models of molecular reorientations such as jumps between a finite number of allowed orientations, rotational diffusion and superimposed reorientations are all investigated with the same formalism. In part two, the effect of the coherent excitation of spins, by multipulse sequences of the WHH-4 type, on the evolution of the heat capacity and spin temperature of the dipolar reservoir is analysed. It is shown both theoretically and experimentally that adiabatic (reversible) reduction of the dipolar Hamiltonian and its spin temperature is obtained when the amplitude of pulses (rotation angle) is slowly raised. The sudden switching on and off of the HW-8 sequence is then shown to lead to the same reversible reduction in a shorter time. It is also shown that, by this way, sensibility and selectivity of double resonance measurements of weak gyromagnetic ratio nuclei are strongly increased. This is experimentally illustrated in some cases. (author)

  2. Spin alignment and resonances in the system 12C+12C - a study with a 4π gamma-spectrometer

    International Nuclear Information System (INIS)

    In order to characterize the resonance behaviour of 12C+12C in the rotational degrees of freedom in the present thesis the alignment of the intrinsic spin(s) in the reactions 12C12C → 12C+12C* (2+, 4.44 MeV) and 12C+12C → 12C*(2+)+12C*(2+) was studied for nine incident energies in the range 19.29 ≤ Ec.m. ≤ 34.65 MeV in dependence on the scattering angle 400 c.m. ≤ 900. From the position-sensitive detection of the particle-particle coincident 4.44-MeV photons by the Darmstadt-Heidelberg crystal-ball spectrometer the scattering amplitudes characterized by the spin-orientation quantum number m for the single-inelastic scattering could be determined nearly completely. Their angular dependence was subjected to a partial wave analysis as its result the angular-momentum distribution is obtained as function of the incident energy and the m quantum number. For the double-inelastic 12C+12C scattering from the 2-photon intensity distribution the probabilities of the correlated alignment of both fragment spins were derived. (orig./HSI)

  3. Studi Spektroskopi Electron Spin Resonance (Esr Lapisan Tipis Amorf Silikon Karbon (A-Sic:H Hasil Deposisi Metode Dc Sputtering

    Directory of Open Access Journals (Sweden)

    Rosari Saleh

    2002-04-01

    Full Text Available The dangling bond defect density in sputtered amorphous silicon carbon alloys have been studied by electron spin resonance (ESR. The results show that the spin density decreased slightly with increasing methane fl ow rate (CH4. The infl uence of carbon and hydrogen incorporation on g-value revealed that for CH4 fl ow rate up to 8 sccm, the ESR signal is dominated by defects characteristic of a-Si:H fi lms and for CH4 fl ow rate higher than 8 sccm the g-value decreased towards those usually found in a-C:H fi lms. Infrared (IR results suggest that as CH4 fl ow rate increases more carbon and hydrogen is incorporated into the fi lms to form Si-H, Si-C and C-H bonds. A direct relation between the IR results and the defect density and g-value is observed.

  4. Dynamical evolution and spin-orbit resonances of potentially habitable exoplanets. The case of GJ 667C

    International Nuclear Information System (INIS)

    We investigate the spin-orbital evolution of the potentially habitable super-Earth GJ 667Cc in the multiple system of at least two exoplanets orbiting a nearby M dwarf. The published radial velocities for this star are re-analyzed and evidence is found for additional periodic signals, which could be taken for two additional planets on eccentric orbits making the system dynamically inviable. Limiting the scope to the two originally detected planets, we assess the dynamical stability of the system and find no evidence for bounded chaos in the orbital motion. The orbital eccentricity of the planets b and c is found to change cyclically in the range 0.06-0.28 and 0.05-0.25, respectively, with a period of approximately 0.46 yr. Taking the eccentricity variation into account, numerical integrations are performed of the spin-orbit interactions of the planet GJ 667Cc with its host star, assuming a terrestrial composition of its mantle. Depending on the interior temperature of the planet, it is likely to be entrapped in the 3:2 (probability 0.51) or even higher spin-orbit resonance. It is less likely to reach the 1:1 resonance (probability 0.24). The estimated characteristic spin-down times are quite short for the two planets, i.e., within 1 Myr for planet c and even shorter for planet b. The rate of tidal dissipation of energy in the planets of GJ 667 is estimated at 1023.7 and 1026.7 J yr–1 for c and b, respectively. This raises a question of how such relatively massive, close super-Earths could survive overheating and destruction.

  5. Resonant blade response in turbine rotor spin tests using a laser-light probe non-intrusive measurement system

    OpenAIRE

    Mansisidor, Michael R.

    2002-01-01

    Procedures to qualify turbo-machinery components for a designed lifetime free of high cycle fatigue (HCF) failures have not yet evolved. As part of an initiative to address this issue, in the present study, laser-light probes were used in a Non- Intrusive Measurement System (NSMS) to measure the unsteady deflections created in the blades of a second-stage turbine rotor in an evacuated spin pit. Air-jet and eddy-current excitation (ECE) methods were used to stimulate blade resonance. The NSMS ...

  6. Assessment of Alzheimer’s Disease Risk with Functional Magnetic Resonance Imaging: An Arterial Spin Labeling Study

    OpenAIRE

    Bangen, Katherine J.; Restom, Khaled; Liu, Thomas T.; Wierenga, Christina E.; Jak, Amy J.; Salmon, David P.; Bondi, Mark W.

    2012-01-01

    Functional magnetic resonance imaging (fMRI) of older adults at risk for Alzheimer’s disease (AD) by virtue of their cognitive (i.e., mild cognitive impairment [MCI]) and/or genetic (i.e., apolipoprotein E [APOE] ε4 allele) status demonstrate divergent brain response patterns during memory encoding across studies. Using arterial spin labeling MRI, we examined the influence of AD risk on resting cerebral blood flow (CBF) as well as the CBF and blood oxygenation level dependent (BOLD) signal re...

  7. NMR spin-lattice relaxation time T(1) of thin films obtained by magnetic resonance force microscopy.

    Science.gov (United States)

    Saun, Seung-Bo; Won, Soonho; Kwon, Sungmin; Lee, Soonchil

    2015-05-01

    We obtained the NMR spectrum and the spin-lattice relaxation time (T1) for thin film samples by magnetic resonance force microscopy (MRFM). The samples were CaF2 thin films which were 50 nm and 150 nm thick. T1 was measured at 18 K using a cyclic adiabatic inversion method at a fixed frequency. A comparison of the bulk and two thin films showed that T1 becomes shorter as the film thickness decreases. To make the comparison as accurate as possible, all three samples were loaded onto different beams of a multi-cantilever array and measured in the same experimental environment. PMID:25828244

  8. NMR spin-lattice relaxation time T1 of thin films obtained by magnetic resonance force microscopy

    Science.gov (United States)

    Saun, Seung-Bo; Won, Soonho; Kwon, Sungmin; Lee, Soonchil

    2015-05-01

    We obtained the NMR spectrum and the spin-lattice relaxation time (T1) for thin film samples by magnetic resonance force microscopy (MRFM). The samples were CaF2 thin films which were 50 nm and 150 nm thick. T1 was measured at 18 K using a cyclic adiabatic inversion method at a fixed frequency. A comparison of the bulk and two thin films showed that T1 becomes shorter as the film thickness decreases. To make the comparison as accurate as possible, all three samples were loaded onto different beams of a multi-cantilever array and measured in the same experimental environment.

  9. Real-time In Situ Electron Spin Resonance Measurements on Fungal Spores of Penicillium digitatum during Exposure of Oxygen Plasmas

    CERN Document Server

    Ishikawa, Kenji; Tanaka, Hiromasa; Tamiya, Kazuhiro; Hashizume, Hiroshi; Ohta, Takayuki; Ito, Masafumi; Iseki, Sachiko; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru

    2012-01-01

    We report the kinetic analysis of free radicals on fungal spores of Penicillium digitatum interacted with atomic oxygen generated plasma electric discharge using real time in situ electron spin resonance (ESR) measurements. We have obtained information that the ESR signal from the spores was observed and preliminarily assignable to semiquinone radical with a g-value of around 2.004 and a line width of approximately 5G. The decay of the signal is possibly linked to the inactivation of the fungal spore. The real-time in situ ESR has proven to be a useful method to elucidate plasma-induced surface reactions on biological specimens.

  10. Dramatic enhancement of fullerene anion formation in polymer solar cells by thermal annealing: Direct observation by electron spin resonance

    OpenAIRE

    Liu, Dong; Nagamori, Tatsuya; Yabusaki, Masaki; Yasuda, Takeshi; HAN, LIYUAN; Marumoto, Kazuhiro

    2014-01-01

    Using electron spin resonance (ESR), we clarified the origin of the efficiency degradation of polymer solar cells containing a lithium-fluoride (LiF) buffer layer created by a thermal annealing process after the deposition of an Al electrode (post-annealing). The device structure was indium-tin-oxide/ poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)/poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM)/LiF/Al. Three samples consisting of quartz/P3HT:PCBM/LiF/Al, qua...

  11. Electric spin resonance and instrumental neutron activation element analyses of Chernobyl nuclear power plant accident clean-up worker teeth

    International Nuclear Information System (INIS)

    Instrumental neutron activation analysis was used to determine the concentrations of macro-, micro-, and trace elements (Ca, Ba, Sr, Mn, Se, Zn, Co) in teeth of Chernobyl's NPP accident clean-up workers examined in the Centre of Occupational and Radiological medicine of P.Stradins Clinical Hospital, Medicine Academy of Latvia. The strontium concentration was high in teeth of clean-up that in control teeth. Electron spin resonance was used to determine the absorption dose. The absorbed dose reconstruction was achieved by additive dose method. The absorbed dose measured by ESR in teeth was always higher than the documented exposure doses. (author)

  12. Ultracold few fermionic atoms in needle-shaped double wells: spin chains and resonating spin clusters from microscopic Hamiltonians emulated via antiferromagnetic Heisenberg and t–J models

    Science.gov (United States)

    Yannouleas, Constantine; Brandt, Benedikt B.; Landman, Uzi

    2016-07-01

    Advances with trapped ultracold atoms intensified interest in simulating complex physical phenomena, including quantum magnetism and transitions from itinerant to non-itinerant behavior. Here we show formation of antiferromagnetic ground states of few ultracold fermionic atoms in single and double well (DW) traps, through microscopic Hamiltonian exact diagonalization for two DW arrangements: (i) two linearly oriented one-dimensional, 1D, wells, and (ii) two coupled parallel wells, forming a trap of two-dimensional, 2D, nature. The spectra and spin-resolved conditional probabilities reveal for both cases, under strong repulsion, atomic spatial localization at extemporaneously created sites, forming quantum molecular magnetic structures with non-itinerant character. These findings usher future theoretical and experimental explorations into the highly correlated behavior of ultracold strongly repelling fermionic atoms in higher dimensions, beyond the fermionization physics that is strictly applicable only in the 1D case. The results for four atoms are well described with finite Heisenberg spin-chain and cluster models. The numerical simulations of three fermionic atoms in symmetric DWs reveal the emergent appearance of coupled resonating 2D Heisenberg clusters, whose emulation requires the use of a t–J-like model, akin to that used in investigations of high T c superconductivity. The highly entangled states discovered in the microscopic and model calculations of controllably detuned, asymmetric, DWs suggest three-cold-atom DW quantum computing qubits.

  13. Photon and spin dependence of the resonance line shape in the strong coupling regime

    International Nuclear Information System (INIS)

    We study the quantum dynamics of a spin ensemble coupled to cavity photons. Recently, related experimental results have been reported, showing the existence of the strong coupling regime in such systems. We study the eigenenergy distribution of the multi-spin system (following the Tavis–Cummings model) which shows a peculiar structure as a function of the number of cavity photons and of spins. We study how this structure causes changes in the spectrum of the admittance in the linear response theory, and also in the frequency dependence of the excited quantities in the stationary state under a probing field. In particular, we investigate how the structure of the higher excited energy levels changes the spectrum from a double-peak structure (the so-called vacuum-field Rabi splitting) to a single-peak structure. We also point out that the spin dynamics in the region of the double-peak structure corresponds to recent experiments using cavity ringing, while in the region of the single-peak structure, it corresponds to the coherent Rabi oscillation in a driving electromagnetic field. Using a standard Lindblad-type mechanism, we study the effect of dissipation on the line width and separation in the computed spectra. In particular, we study the relaxation of the total spin in the general case of a spin ensemble in which the total spin of the system is not specified. The theoretical results are correlated with experimental evidence of the strong coupling regime, achieved with a spin-1/2 ensemble. (paper)

  14. Neutron spin resonance study in Co-doped NaFeAs

    Science.gov (United States)

    Zhang, Chenglin; Takeshi, Egami; Dai, Pengcheng; UTK and Rice Team

    2014-03-01

    Since the discovery of iron superconductors, the (Ba,Sr,Ca)Fe2As2 (``122'') family especially electron doped side has been subjected to heavily study byneutron scattering. One of the pronounced features generally observed in bulk superconducting compositions is a broad resonance along antiferrromagnetic order wave vector. The resonance energy linearly scales with Tc. However, our neutron study shows that Co-doped NaFeAs system exhibits complexity, distinguishing itself from ``122'' system. We observed a sharp resonance in the electron-overdope regime, providing strong evidence for S +_ pairing symmetry in pnictide superconductors. In the underdoped regime, we find double resonances at commensurate wave vector, demonstrating the multi-orbital nature of pnictides. Our finding further suggests that the resonance energy and Tc may not be simply correlated in multiband superconductors such as iron pnictides. We will discuss in detail how resonances evolve with electron doping.

  15. Zero field spin polarization in a 2D paramagnetic resonant tunneling diode

    OpenAIRE

    Rüth, M; Gould, C.; Molenkamp, L. W.

    2010-01-01

    We study I-V characteristics of an all-II-VI semiconductor resonant tunneling diode with dilute magnetic impurities in the quantum well layer. Bound magnetic polaron states form in the vicinity of potential fluctuations at the well interface while tunneling electrons traverse these interface quantum dots. The resulting microscopic magnetic order lifts the degeneracy of the resonant tunneling states. Although there is no macroscopic magnetization, the resulting resonant tunneling current is hi...

  16. Instrumental aspects of high-field force-detected electron spin resonance

    OpenAIRE

    Cruickshank, Paul Alexander Sawchuk

    2003-01-01

    Magnetic resonance force microscopy (MRFM) is a new measurement technique combining scanning probe microscopy (SPM) and MR spectroscopy, offering the potential of high resolution chemical specific imaging. MRFM is based on the principle of force detection of magnetic resonance (FDMR) in which the magnetisation of a sample in a magnetic field is coupled to an atomic force microscopy cantilever via a field gradient. Magnetic resonance is used to modulate the sample magnetisation ...

  17. Electron spin resonance study of the La{sub 0.8}Sr{sub 0.2}MnO{sub 3} nanoparticle-decorated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dowan; Lee, Kyu Won [Department of Physics, Korea University, Seoul 136-713 (Korea, Republic of); Choi, E.H. [Department of Electrophysics, Kwangwoon University, Seoul 130-701 (Korea, Republic of); Lee, Cheol Eui, E-mail: rscel@korea.ac.kr [Department of Physics, Korea University, Seoul 136-713 (Korea, Republic of)

    2014-11-15

    Graphical abstract: Inverse spin susceptibilities obtained by integration of the distinct ESR line components of the LSMO-CNTs system as a function of temperature. - Highlights: • Spin/charge dynamics in La{sub 0.8}Sr{sub 0.2}MnO{sub 3}-decorated CNTs studied by EPR. • One spin species revealed only paramagnetic–superparamagnetic phase transition. • Another spin species manifested reflected weak localization of spin/charge carriers. • Spins participating in the magnetic phase transition and the itinerant spins well separated by EPR. - Abstract: We have studied La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSMO) nanoparticle-decorated carbon nanotubes (CNTs) by means of the electron spin resonance (ESR) spectroscopy in view of our previous work on the magnetic and electrical properties of the system. One of the line components of the ESR spectrum reflected a paramagnetic–superparamagnetic phase transition at T{sub SP}∼200 K, which is accompanied by a concomitant metal–insulator transition (MIT) associated with charge transport taking place through the CNTs network triggered by the LSMO nanoparticles. On the other hand, another ESR line component revealed anomalies at T{sub WL}∼170 K as well, attributable to a 2D weak localization effect of the spin/charge carriers. Thus, magnetic interactions and dynamics of the distinct spin species were sensitively reflected in the LSMO-CNTs system.

  18. Electron spin resonance study of the La0.8Sr0.2MnO3 nanoparticle-decorated carbon nanotubes

    International Nuclear Information System (INIS)

    Graphical abstract: Inverse spin susceptibilities obtained by integration of the distinct ESR line components of the LSMO-CNTs system as a function of temperature. - Highlights: • Spin/charge dynamics in La0.8Sr0.2MnO3-decorated CNTs studied by EPR. • One spin species revealed only paramagnetic–superparamagnetic phase transition. • Another spin species manifested reflected weak localization of spin/charge carriers. • Spins participating in the magnetic phase transition and the itinerant spins well separated by EPR. - Abstract: We have studied La0.8Sr0.2MnO3 (LSMO) nanoparticle-decorated carbon nanotubes (CNTs) by means of the electron spin resonance (ESR) spectroscopy in view of our previous work on the magnetic and electrical properties of the system. One of the line components of the ESR spectrum reflected a paramagnetic–superparamagnetic phase transition at TSP∼200 K, which is accompanied by a concomitant metal–insulator transition (MIT) associated with charge transport taking place through the CNTs network triggered by the LSMO nanoparticles. On the other hand, another ESR line component revealed anomalies at TWL∼170 K as well, attributable to a 2D weak localization effect of the spin/charge carriers. Thus, magnetic interactions and dynamics of the distinct spin species were sensitively reflected in the LSMO-CNTs system

  19. Resonances in field-cycling NMR on molecular crystals. (reversible) Spin dynamics or (irreversible) relaxation?

    International Nuclear Information System (INIS)

    Multi spin systems with spin 1/2 nuclei and dipolar coupled quadrupolar nuclei can show so called ''quadrupolar dips''. There are two main reasons for this behavior: polarization transfer and relaxation. They look quite alike and without additional research cannot be differentiated easily in most cases. These two phenomena have quite different physical and theoretical backgrounds. For no or very slow dynamics, polarization transfer will take place, which is energy conserving inside the spin system. This effect can entirely be described using quantum mechanics on the spin system. Detailed knowledge about the crystallography is needed, because this affects the relevant hamiltonians directly. For systems with fast enough dynamics, relaxation takes over, and the energy flows from the spin system to the lattice; thus a more complex theoretical description is needed. This description has to include a dynamic model, usually in the form of a spectral density function. Both models should include detailed modelling of the complete spin system. A software library was developed to be able to model complex spin systems. It allows to simulate polarization transfer or relaxation effects. NMR measurements were performed on the protonic conductor K3H(SO4)2. A single crystal shows sharp quadrupolar dips at room temperature. Dynamics could be excluded using relaxation measurements and literature values. Thus, a polarization transfer analysis was used to describe those dips with good agreement. As a second system, imidazolium based molecular crystals were analyzed. The quadrupolar dips were expected to be caused by polarization transfer; this was carefully analyzed and found not to be true. A relaxation based analysis shows good agreement with the measured data in the high temperature area. It leverages a two step spectral density function, which indicates two distinct dynamic processes happening in this system.

  20. Optical-optical double resonance, laser induced fluorescence, and revision of the signs of the spin-spin constants of the boron carbide (BC) free radical

    Science.gov (United States)

    Sunahori, Fumie X.; Nagarajan, Ramya; Clouthier, Dennis J.

    2015-12-01

    The cold boron carbide free radical (BC X 4Σ-) has been produced in a pulsed discharge free jet expansion using a precursor mixture of trimethylborane in high pressure argon. High resolution laser induced fluorescence spectra have been obtained for the B 4Σ--X 4Σ- and E 4Π-X 4Σ- band systems of both 11BC and 10BC. An optical-optical double resonance (OODR) scheme was implemented to study the finer details of both band systems. This involved pumping a single rotational level of the B state with one laser and then recording the various allowed transitions from the intermediate B state to the final E state with a second laser by monitoring the subsequent E-X ultraviolet fluorescence. In this fashion, we were able to prove unambiguously that, contrary to previous studies, the spin-spin constant λ is negative in the ground state and positive in the B 4Σ- excited state. It has been shown that λ″ < 0 is in fact expected based on a semiempirical second order perturbation theory calculation of the magnitude of the spin-spin constant. The OODR spectra have also been used to validate our assignments of the complex and badly overlapped E 4Π-X 4Σ- 0-0 and 1-0 bands of 11BC. The E-X 0-0 band of 10BC was found to be severely perturbed. The ground state main electron configuration is …3σ24σ25σ11π22π0 and the derived bond lengths show that there is a 0.03 Å contraction in the B state, due to the promotion of an electron from the 4σ antibonding orbital to the 5σ bonding orbital. In contrast, the bond length elongates by 0.15 Å in the E state, a result of promoting an electron from the 5σ bonding orbital to the 2π antibonding orbitals.

  1. Optical-optical double resonance, laser induced fluorescence, and revision of the signs of the spin-spin constants of the boron carbide (BC) free radical

    International Nuclear Information System (INIS)

    The cold boron carbide free radical (BC X 4Σ−) has been produced in a pulsed discharge free jet expansion using a precursor mixture of trimethylborane in high pressure argon. High resolution laser induced fluorescence spectra have been obtained for the B 4Σ−–X 4Σ− and E 4Π–X 4Σ− band systems of both 11BC and 10BC. An optical-optical double resonance (OODR) scheme was implemented to study the finer details of both band systems. This involved pumping a single rotational level of the B state with one laser and then recording the various allowed transitions from the intermediate B state to the final E state with a second laser by monitoring the subsequent E–X ultraviolet fluorescence. In this fashion, we were able to prove unambiguously that, contrary to previous studies, the spin-spin constant λ is negative in the ground state and positive in the B 4Σ− excited state. It has been shown that λ″ < 0 is in fact expected based on a semiempirical second order perturbation theory calculation of the magnitude of the spin-spin constant. The OODR spectra have also been used to validate our assignments of the complex and badly overlapped E 4Π–X 4Σ− 0-0 and 1-0 bands of 11BC. The E–X 0-0 band of 10BC was found to be severely perturbed. The ground state main electron configuration is …3σ24σ25σ11π22π0 and the derived bond lengths show that there is a 0.03 Å contraction in the B state, due to the promotion of an electron from the 4σ antibonding orbital to the 5σ bonding orbital. In contrast, the bond length elongates by 0.15 Å in the E state, a result of promoting an electron from the 5σ bonding orbital to the 2π antibonding orbitals

  2. Optical-optical double resonance, laser induced fluorescence, and revision of the signs of the spin-spin constants of the boron carbide (BC) free radical

    Energy Technology Data Exchange (ETDEWEB)

    Sunahori, Fumie X. [Department of Chemistry and Physics, Franklin College, Franklin, Indiana 46131 (United States); Nagarajan, Ramya; Clouthier, Dennis J., E-mail: dclaser@uky.edu [Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055 (United States)

    2015-12-14

    The cold boron carbide free radical (BC X {sup 4}Σ{sup −}) has been produced in a pulsed discharge free jet expansion using a precursor mixture of trimethylborane in high pressure argon. High resolution laser induced fluorescence spectra have been obtained for the B {sup 4}Σ{sup −}–X {sup 4}Σ{sup −} and E {sup 4}Π–X {sup 4}Σ{sup −} band systems of both {sup 11}BC and {sup 10}BC. An optical-optical double resonance (OODR) scheme was implemented to study the finer details of both band systems. This involved pumping a single rotational level of the B state with one laser and then recording the various allowed transitions from the intermediate B state to the final E state with a second laser by monitoring the subsequent E–X ultraviolet fluorescence. In this fashion, we were able to prove unambiguously that, contrary to previous studies, the spin-spin constant λ is negative in the ground state and positive in the B {sup 4}Σ{sup −} excited state. It has been shown that λ″ < 0 is in fact expected based on a semiempirical second order perturbation theory calculation of the magnitude of the spin-spin constant. The OODR spectra have also been used to validate our assignments of the complex and badly overlapped E {sup 4}Π–X {sup 4}Σ{sup −} 0-0 and 1-0 bands of {sup 11}BC. The E–X 0-0 band of {sup 10}BC was found to be severely perturbed. The ground state main electron configuration is …3σ{sup 2}4σ{sup 2}5σ{sup 1}1π{sup 2}2π{sup 0} and the derived bond lengths show that there is a 0.03 Å contraction in the B state, due to the promotion of an electron from the 4σ antibonding orbital to the 5σ bonding orbital. In contrast, the bond length elongates by 0.15 Å in the E state, a result of promoting an electron from the 5σ bonding orbital to the 2π antibonding orbitals.

  3. Radio-frequency magnetic susceptibility of spin ice crystals Dy2Ti2O7 using tunnel diode resonator

    Science.gov (United States)

    Teknowijoyo, Serafim; Cho, Kyuil; Tanatar, Makariy A.; Prozorov, Ruslan; Cava, Robert J.; Krizan, Jason W.; Ames Laboratory; Iowa State University Team; Princeton University Collaboration

    Spin ice compound, Dy2Ti2O7, has shown complex frequency - dependent magnetic behavior at low temperatures. While the DC measurements show conventional paramagnetic behavior, finite frequency susceptibility shows two regimes, - complex kagomé ice behavior at around 2 K and spin collective behavior above 10 K, depending on the frequency. Conventional AC susceptometry is limited to frequencies in a kHz range, but to get an insight into the possible Arrhenius activated behavior and characteristic relaxation times, higher frequencies are desired. We used self-oscillating tunnel-diode resonator (TDR) to probe magnetic susceptibility at 14.6 MHz, in the presence of a DC magnetic field and down to 50 mK. We found an unusual non-monotonic field dependence of the lower transition temperature, most likely associated with different spin configurations in a kagomé ice and an activated behavior of the upper transition, which has now shifted to 50 K range. This work was supported by the U.S. DOE BES MSED and was performed at the Ames Laboratory, Iowa State University under Contract DE-AC02-07CH11358. The work at Princeton university was supported by DOE BES Grant Number DE-FG02-08ER46544.

  4. Electron spin resonance studies of ribulosebisphosphate carboxylase: identification of activator cation ligands.

    Science.gov (United States)

    Miziorko, H M; Sealy, R C

    1984-01-31

    Ribulosebisphosphate carboxylase (RuBP carboxylase)forms a stable model complex containing stoichiometric amounts of enzyme sites, activator C0(2), divalent activator cation, and the transition-state analogue carboxyarabinitol bisphosphate (CABP). Incorporation of Mn(2+) in the model complex permits investigation of the environment of the activator cation by electron spin resonance (ESR)techniques. Measurements at 9 GHz on the Mn(2+)-containing complex prepared by using dimeric Rhodospirillum rubrum enzyme produce a spectrum which indicates that the cation is bound in an anisotropic environment. Measurements at 9 GHz on the spinach enzyme model complex produce a spectrum in which several of the fine structure transitions are obvious. In contrast, the spectrum produced from Mn(2+) bound to R. rubrum enzyme exhibits an intense powder pattern for the central fine structure transition; the other four fine structure transitions produce powder patterns that are in homogeneously broadened and therefore are not as apparent.Low-temperature measurements at high field (35 GHz) result in substantially simplified spectra. The spectrum of Mn(2+) bound to the R. rubrum enzyme shows less fine structure than the spectrum of Mn(2+) bound in the octameric spinach enzyme complex, where substantial hyperfine splitting is resolved in three of the five fine structure transitions. Measurements at 35 GHz on Mn (2+) bound in the dimeric R. rubrum enzyme complex produce spectra in which only the central fine structure transition produces a prominent signal. However, these samples are characterized by several narrow spectral features which permit investigation of the identity of Mn(2+)ligands by 170 perturbation techniques. Preparation of the R. rubrum RuBP carboxylase model complex in (17)O-enriched water results in a sample which exhibits an obviously broadened 35-GHz Mn(2+) spectrum in comparison to unenriched samples. Removal of H(2)(17)O by gel filtration abolished the spectral

  5. Assignment of hyperfine shifted haem methyl carbon resonances in paramagnetic low-spin met-cyano complex of sperm whale myoglobin

    International Nuclear Information System (INIS)

    The hyperfine shifted resonances arising from all four individual haem carbons of the paramagnetic low-spin met-cyano complex of sperm whale myoglobin have been clearly identified and assigned for the first time with the aid of 1H-13C heteronuclear chemical shift correlated spectroscopy. Alteration of the in-plane symmetry of the electronic structure of haem induced by the ligation of proximal histidyl imidazole spreads the haem carbon resonances to 32 ppm at 220C, indicating the sensitivity of those resonances to the haem electronic/molecular structure. Those resonances are potentially powerful probes in characterizing the nature of haem electronic structure. 25 refs.; 2 figs.; 1 table

  6. Hole spin injection from a GaMnAs layer into GaAs-AlAs-InGaAs resonant tunneling diodes

    Science.gov (United States)

    Rodrigues, D. H.; Brasil, M. J. S. P.; Orlita, M.; Kunc, J.; Galeti, H. V. A.; Henini, M.; Taylor, D.; Galvão Gobato, Y.

    2016-04-01

    We have investigated the polarization-resolved electroluminescence (EL) of a p-i-n GaAs/AlAs/InGaAs resonant tunneling diode (RTD) containing a GaMnAs (x  =  5%) spin injector under high magnetic fields. We demonstrate that under hole resonant tunneling condition, the GaMnAs contact acts as an efficient spin-polarized source for holes tunneling through the device. Polarization degrees up to 80% were observed in the device around the hole resonance at 2 K under 15 T. Our results could be valuable for improving the hole-spin injection in GaMnAs-based spintronic devices.

  7. Spin polarized low energy electron microscopy of quantum well resonances in Fe films on the Cu-covered W(110) surface.

    Science.gov (United States)

    Wu, Qiang; Altman, M S

    2013-07-01

    Spin polarized low energy electron microscopy has been used to investigate the quantum size effect (QSE) in electron reflectivity from Fe films grown on a pseudomorphic Cu layer on a W(110) surface. Intensity oscillations caused by the QSE as functions of Fe film thickness and incident electron energy identify quantum well resonance conditions in the film. Evaluation of these intensity oscillations using the phase accumulation model provides information on the unoccupied spin polarized band structure in the Fe film above the vacuum level. We also find evidence that the presence of the non-magnetic Cu layer shifts spin polarized quantum well resonances in the Fe layer uniformly downward in energy by 1.1eV compared to Fe/W(110) films without an interface Cu layer, suggesting that the Cu layer gives a small degree of control over the quantum well resonances. PMID:23628648

  8. Electron spin resonance and optical absorption spectroscopic studies of Cu2+ ions in aluminium lead borate glasses

    International Nuclear Information System (INIS)

    Highlights: ► It is for the first time to study optical absorption and EPR in these glasses. ► The thermal properties are new and interesting in this glass system. ► It is for the first time to report three optical bands for Cu2+ in oxide glasses. ► The interesting optical results are due to excellent sample preparation. - Abstract: Electron Spin Resonance and optical absorption spectral studies of Cu2+ ions in 5 Al2O3 + 75 B2O3 + (20-z) PbO + z CuO (where z = 0.1–1.5 mol.% of CuO) glasses have been reported. The EPR spectra of all the glasses show resonance signals characteristic of Cu2+ ions at both room and low temperatures. The number of spins and Gibbs energy were calculated at different concentrations and temperatures. From the plot of the ratio of logarithmic number of spins and absolute temperature and the reciprocal of absolute temperature, the entropy and enthalpy have been evaluated. The optical absorption spectra of all the glasses exhibit three bands and these bands have been assigned to 2B1g → 2Eg, 2B1g → 2B2g, and 2B1g → 2A1g transitions in the decreasing order of energy. It is for the first time to observe three optical absorption bands for Cu2+ ions in oxide glasses. Such type of results is due to excellent sample preparation. From the EPR and optical absorption spectroscopies data, the molecular orbital coefficients have been evaluated.

  9. Multiple quantum filtered nuclear magnetic resonance spectroscopy of spin 7/2 nuclei in solution

    Science.gov (United States)

    Tsoref, L.; Eliav, U.; Navon, G.

    1996-03-01

    Multiple quantum dynamics of spin I=7/2 are presented considering modulation of quadrupolar interaction as the relaxation mechanism. The equation of motion of the spin system is calculated in Liouville space using irreducible spherical tensor operators as the orthonormal basis. Relaxation matrices are given explicitly for coherences one to seven. Experiments for measuring the creation of multiple rank tensors and multiple quantum relaxation for spin 7/2 are described and analyzed. Results of double quantum and triple quantum filtered spectra of Cs+ bound to the crown ether 18-crown-6, dissolved in glycerol, were analyzed in terms of the microscopic parameters of the system, the reorientation correlation time and the quadrupolar coupling constant. Numerical calculations indicated that the expected MQF signal intensities decrease in the order TQF≳DQF≫5QF≳4QF≫7QF≳6QF.

  10. Multi-resonance orbital model of high-frequency quasi-periodic oscillations: possible high-precision determination of black hole and neutron star spin

    CERN Document Server

    Stuchlik, Zdenek; Torok, Gabriel

    2013-01-01

    Using known frequencies of the twin-peak high-frequency quasiperiodic oscillations (HF QPOs) and known mass of the central black hole, the black-hole dimensionless spin can be determined by assuming a concrete version of the resonance model. However, a wide range of observationally limited values of the black hole mass implies low precision of the spin estimates. We discuss the possibility of higher precision of the black hole spin measurements in the framework of a multi-resonance model inspired by observations of more than two HF QPOs in the black hole systems, which are expected to occur at two (or more) different radii of the accretion disc. For the black hole systems we focus on the special case of duplex frequencies, when the top, bottom, or mixed frequency is common at two different radii where the resonances occur giving triple frequency sets. The sets of triple frequency ratios and the related spin are given. The strong resonance model for "magic" values of the black hole spin means that two (or more...

  11. Examination of gamma-irradiated fruits and vegetables by electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    The ESR spectra of the seeds, pits, shells, and skins of a variety of irradiated fruits and vegetables were measured. All spectra, control and irradiated, contained a single resonance with a g-factor of 2.00. Additional resonances due to Mn2+ were observed for the drupelets of blackberries and red raspberries. An unusual radiation-induced radical was observed for irradiated mango seed; however, the signal decayed completely within a few days. It was concluded that only in a few specialized cases could the ESR resonances observed be suitable for postirradiation monitoring or dosimetry. (author)

  12. Examination of gamma-irradiated fruits and vegetables by electron spin resonance spectroscopy

    Science.gov (United States)

    Desrosiers, Marc F.; McLaughlin, William L.

    The ESR spectra of the seeds, pits, shells, and skins of a variety of irradiated fruits and vegetables were measured. All spectra, control and irradiated, contained a single resonance with a g-factor of 2.00. Additional resonances due to Mn 2+ were observed for the drupelets of blackberries and red raspberries. An unusual radiation-induced radical was observed for irradiated mango seed; however, the signal decayed completely within a few days. It was concluded that only in a few specialized cases could the ESR resonances observed be suitable for postirradiation monitoring or dosimetry.

  13. Examination of gamma-irradiated fruits and vegetables by electron spin resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Desrosiers, M.F.; McLaughlin, W.L. (National Inst. of Standards and Technology (NML), Gaithersburg, MD (USA). Center for Radiation Research)

    1989-01-01

    The ESR spectra of the seeds, pits, shells, and skins of a variety of irradiated fruits and vegetables were measured. All spectra, control and irradiated, contained a single resonance with a g-factor of 2.00. Additional resonances due to Mn{sup 2+} were observed for the drupelets of blackberries and red raspberries. An unusual radiation-induced radical was observed for irradiated mango seed; however, the signal decayed completely within a few days. It was concluded that only in a few specialized cases could the ESR resonances observed be suitable for postirradiation monitoring or dosimetry. (author).

  14. Nonlinear magnetization dynamics of antiferromagnetic spin resonance induced by intense terahertz magnetic field

    CERN Document Server

    Mukai, Y; Yamamoto, T; Kageyama, H; Tanaka, K

    2016-01-01

    We report on the nonlinear magnetization dynamics of a HoFeO3 crystal induced by a strong terahertz magnetic field resonantly enhanced with a split ring resonator and measured with magneto-optical Kerr effect microscopy. The terahertz magnetic field induces a large change (~40%) in the spontaneous magnetization. The frequency of the antiferromagnetic resonance decreases in proportion to the square of the magnetization change. A modified Landau-Lifshitz-Gilbert equation with a phenomenological nonlinear damping term quantitatively reproduced the nonlinear dynamics.

  15. Mn concentration and quantum size effects on spin-polarized transport through CdMnTe based magnetic resonant tunneling diode.

    Science.gov (United States)

    Mnasri, S; Abdi-Ben Nasrallahl, S; Sfina, N; Lazzari, J L; Saïd, M

    2012-11-01

    Theoretical studies on spin-dependent transport in magnetic tunneling diodes with giant Zeeman splitting of the valence band are carried out. The studied structure consists of two nonmagnetic layers CdMgTe separated by a diluted magnetic semiconductor barrier CdMnTe, the hole is surrounded by two p-doped CdTe layers. Based on the parabolic valence band effective mass approximation and the transfer matrix method, the magnetization and the current densities for holes with spin-up and spin-down are studied in terms of the Mn concentration, the well and barrier thicknesses as well as the voltage. It is found that, the current densities depend strongly on these parameters and by choosing suitable values; this structure can be a good spin filter. Such behaviors are originated from the enhancement and suppression in the spin-dependent resonant states. PMID:23421288

  16. Devices and process for high-pressure magic angle spinning nuclear magnetic resonance

    Science.gov (United States)

    Hoyt, David W; Sears, Jr., Jesse A; Turcu, Romulus V.F.; Rosso, Kevin M; Hu, Jian Zhi

    2014-04-08

    A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.

  17. Isotropic three-dimensional fast spin-echo Cube magnetic resonance dacryocystography: comparison with the three-dimensional fast-recovery fast spin-echo technique

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing; Chen, Lang; Wang, Qiu-Xia; Zhu, Wen-Zhen; Luo, Xin; Peng, Li [Huazhong University of Science and Technology, Department of Radiology, Tongji Hospital, Wuhan (China); Liu, Rong [Huazhong University of Science and Technology, Department of Ophthalmology, Tongji Hospital, Wuhan (China); Xiong, Wei [GE Healthcare China Wuhan Office, Wuhan (China)

    2015-04-01

    Three-dimensional fast spin-echo Cube (3D-FSE-Cube) uses modulated refocusing flip angles and autocalibrates two dimensional (2D)-accelerated parallel and nonlinear view ordering to produce high-quality volumetric image sets with high-spatial resolution. Furthermore, 3D-FSE-Cube with topical instillation of fluid can also be used for magnetic resonance dacryocystography (MRD) with good soft tissue contrast. The purpose of this study was to evaluate the technical quality and visualization of the lacrimal drainage system (LDS) when using the 3D-FSE-Cube sequence and the 3D fast-recovery fast spin-echo (FRFSE) sequence. In total, 75 patients with primary LDS outflow impairment or postsurgical recurrent epiphora underwent 3D-FSE-Cube MRD and 3D-FRFSE MRD at 3.0 T after topical administration of compound sodium chloride eye drops. Two radiologists graded the images from either of the two sequences in a blinded fashion, and appropriate statistical tests were used to assess differences in technical quality, visibility of ductal segments, and number of segments visualized per LDS. Obstructions were confirmed in 90 of the 150 LDSs assessed. The technical quality of 3D-FSE-Cube MRD and 3D-FRFSE MRD was statistically equivalent (P = 0.871). However, compared with 3D-FRFSE MRD, 3D-FSE-Cube MRD improved the overall visibility and the visibility of the upper drainage segments in normal and obstructed LDSs (P < 0.001). There was a corresponding increase in the number of segments visualized per LDS in both groups (P < 0.001). Compared with 3D-FRFSE MRD, 3D-FSE-Cube MRD potentially improves the visibility of the LDS. (orig.)

  18. Isotropic three-dimensional fast spin-echo Cube magnetic resonance dacryocystography: comparison with the three-dimensional fast-recovery fast spin-echo technique

    International Nuclear Information System (INIS)

    Three-dimensional fast spin-echo Cube (3D-FSE-Cube) uses modulated refocusing flip angles and autocalibrates two dimensional (2D)-accelerated parallel and nonlinear view ordering to produce high-quality volumetric image sets with high-spatial resolution. Furthermore, 3D-FSE-Cube with topical instillation of fluid can also be used for magnetic resonance dacryocystography (MRD) with good soft tissue contrast. The purpose of this study was to evaluate the technical quality and visualization of the lacrimal drainage system (LDS) when using the 3D-FSE-Cube sequence and the 3D fast-recovery fast spin-echo (FRFSE) sequence. In total, 75 patients with primary LDS outflow impairment or postsurgical recurrent epiphora underwent 3D-FSE-Cube MRD and 3D-FRFSE MRD at 3.0 T after topical administration of compound sodium chloride eye drops. Two radiologists graded the images from either of the two sequences in a blinded fashion, and appropriate statistical tests were used to assess differences in technical quality, visibility of ductal segments, and number of segments visualized per LDS. Obstructions were confirmed in 90 of the 150 LDSs assessed. The technical quality of 3D-FSE-Cube MRD and 3D-FRFSE MRD was statistically equivalent (P = 0.871). However, compared with 3D-FRFSE MRD, 3D-FSE-Cube MRD improved the overall visibility and the visibility of the upper drainage segments in normal and obstructed LDSs (P < 0.001). There was a corresponding increase in the number of segments visualized per LDS in both groups (P < 0.001). Compared with 3D-FRFSE MRD, 3D-FSE-Cube MRD potentially improves the visibility of the LDS. (orig.)

  19. Orientation and Lipid-Peptide Interactions of Gramicidin A in Lipid Membranes: Polarized Attenuated Total Reflection Infrared Spectroscopy and Spin-Label Electron Spin Resonance

    Science.gov (United States)

    Kóta, Zoltán; Páli, Tibor; Marsh, Derek

    2004-01-01

    Gramicidin A was incorporated at a peptide/lipid ratio of 1:10 mol/mol in aligned bilayers of dimyristoyl phosphatidylcholine (DMPC), phosphatidylserine (DMPS), phosphatidylglycerol (DMPG), and phosphatidylethanolamine (DMPE), from trifluoroethanol. Orientations of the peptide and lipid chains were determined by polarized attenuated total reflection infrared spectroscopy. Lipid-peptide interactions with gramicidin A in DMPC bilayers were studied with different spin-labeled lipid species by using electron spin resonance spectroscopy. In DMPC membranes, the orientation of the lipid chains is comparable to that in the absence of peptide, in both gel and fluid phases. In gel-phase DMPC, the effective tilt of the peptide exceeds that of the lipid chains, but in the fluid phase both are similar. For gramicidin A in DMPS, DMPG, and DMPE, the degree of orientation of the peptide and lipid chains is less than in DMPC. In the fluid phase of DMPS, DMPG, and DMPE, gramicidin A is also less well oriented than are the lipid chains. In DMPE especially, gramicidin A is largely disordered. In DMPC membranes, three to four lipids per monomer experience direct motional restriction on interaction with gramicidin A. This is approximately half the number of lipids expected to contact the intramembranous perimeter of the gramicidin A monomer. A selectivity for certain negatively charged lipids is found in the interaction with gramicidin A in DMPC. These results are discussed in terms of the integration of gramicidin A channels in lipid bilayers, and of the interactions of lipids with integral membrane proteins. PMID:14990479

  20. Effect of Electric and Magnetic Fields on Spin Dynamics in the Resonant Electric Dipole Moment Experiment

    OpenAIRE

    Silenko, A. J.

    2013-01-01

    A buildup of the vertical polarization in the resonant electric dipole moment (EDM) experiment [Y. F. Orlov, W. M. Morse, and Y. K. Semertzidis, Phys. Rev. Lett. 96, 214802 (2006)] is affected by a horizontal electric field in the particle rest frame oscillating at a resonant frequency. This field is defined by the Lorentz transformation of an oscillating longitudinal electric field and a uniform vertical magnetic one. The effect of a longitudinal electric field is significant, while the cont...

  1. Decoherence dynamics of a single spin versus spin ensemble

    NARCIS (Netherlands)

    Dobrovitski, V.V.; Feiguin, A.E.; Awschalom, D.D.; Hanson, R.

    2008-01-01

    We study decoherence of central spins by a spin bath, focusing on the difference between measurement of a single central spin and measurement of a large number of central spins (as found in typical spin-resonance experiments). For a dilute spin bath, the single spin demonstrates Gaussian free-induct

  2. Resonance Spin Memory in Low-Energy Gamma-Ray Spectra from Sb, Tb, Ho and Ta Odd-Odd Compound Nuclei

    CERN Document Server

    Olejniczak, U; Pikelner, L B; Przytula, M; Serov, D G

    2002-01-01

    The low-energy gamma-ray spectra from neutron resonance capture with natural samples of Sb, Tb, Ho and Ta were measured using HPGe detector at IBR-30 pulsed reactor (JINR, Dubna). The resonance spin memory effect in the spectra from the odd-odd compound nuclei of ^{122}Tb, ^{160}Tb and ^[166}Ho was found to be quite distinct. For the ^{182}Ta compound nucleus it proved to be rather weak.

  3. Resonance spin memory in low-energy gamma-ray spectra from Sb, Tb, Ho and Ta odd-odd compound nuclei

    International Nuclear Information System (INIS)

    The low-energy gamma-ray spectra from neutron resonance capture with natural samples of Sb, Tb, Ho and Ta were measured using a HPGe detector at the IBR-30 pulsed reactor (JINR, Dubna). The resonance spin memory effect in the spectra from the odd-odd compound nuclei of 122Sb, 160Tb and 166Ho was found to be quite distinct. For the 182Ta compound nucleus it proved to be rather weak

  4. Ligand-based transport resonances of single-molecule magnet spin filters: Suppression of the Coulomb blockade and determination of the orientation of the magnetic easy axis

    OpenAIRE

    Renani, Fatemeh Rostamzadeh; Kirczenow, George

    2011-01-01

    We investigate single molecule magnet transistors (SMMTs) with ligands that support transport resonances. We find the lowest unoccupied molecular orbitals of Mn12-benzoate SMMs (with and without thiol or methyl-sulfide termination) to be on ligands, the highest occupied molecular orbitals being on the Mn12 magnetic core. We predict gate controlled switching between Coulomb blockade and coherent resonant tunneling in SMMTs based on such SMMs, strong spin filtering by the SMM in both transport ...

  5. 电子自旋共振扫描隧道显微镜%Electron spin resonance scanning tunneling microscope

    Institute of Scientific and Technical Information of China (English)

    郭阳; 李健梅; 陆兴华

    2015-01-01

    单电子自旋极有可能发展成为未来信息学的基础。以电子自旋为核心的新型单分子或单原子器件将最终成为基本信息单元,基于单电子的自旋态将有可能构筑未来量子计算机的量子比特。但是,如何实现对单个电子自旋及其相干态和纠缠态的测量和控制,目前仍然是一个很大的挑战。作为调控单个电子自旋的重要实验手段,电子自旋共振扫描隧道显微镜的发展一直备受关注。文章简要介绍了电子自旋共振扫描隧道显微镜的基本概念,阐述了其发展历史和最新进展,归纳了机理探索的研究成果,论述了该设备研发面临的挑战与对策,并对未来的发展和应用做了展望。%It is highly expected that the future informatics will be based on the spins of in-dividual electrons. The development of elementary information unit will eventually leads to novel single-molecule or single-atom devices based on electron spins;the quantum computer in the fu-ture can be constructed with single electron spins as the basic quantum bits. However, it is still a great challenge in detection and manipulation of a single electron spin, as well as its coherence and entanglement. As an ideal experimental tool for such tasks, the development of electron spin resonance scanning tunneling microscope (ESR-STM) has attracted great attention for decades. This paper briefly introduces the basic concept of ESR-STM. The development history of this in-strument and recent progresses are reviewed. The underlying mechanism is explored and summa-rized. The challenges and possible solutions are discussed. Finally, the prospect of future direction and applications are presented.

  6. Strain gauge measurements of blade resonance using eddy current excitation in a vacuum spin pit

    OpenAIRE

    Russell, Scott A.

    2002-01-01

    As part of an on going High Cycle Fatigue program related to gas turbine engines, which is sponsored jointly by the Naval Air Systems Command and the Air Force, unsteady strain gauge measurements were made on a 37.5 inch diameter titanium rotor in the Naval Postgraduate School, Turbopropulsion Laboratory vacuum spin pit. Vibratory excitation was produced by a number of evenly spaced magnets positioned around the rotor perimeter, which generated eddy currents in the blades and associated magne...

  7. Valley and spin resonant tunneling current in ferromagnetic/nonmagnetic/ferromagnetic silicene junction

    Directory of Open Access Journals (Sweden)

    Yaser Hajati

    2016-02-01

    Full Text Available We study the transport properties in a ferromagnetic/nonmagnetic/ferromagnetic (FNF silicene junction in which an electrostatic gate potential, U, is attached to the nonmagnetic region. We show that the electrostatic gate potential U is a useful probe to control the band structure, quasi-bound states in the nonmagnetic barrier as well as the transport properties of the FNF silicene junction. In particular, by introducing the electrostatic gate potential, both the spin and valley conductances of the junction show an oscillatory behavior. The amplitude and frequency of such oscillations can be controlled by U. As an important result, we found that by increasing U, the second characteristic of the Klein tunneling is satisfied as a result of the quasiparticles chirality which can penetrate through a potential barrier. Moreover, it is found that for special values of U, the junction shows a gap in the spin and valley-resolve conductance and the amplitude of this gap is only controlled by the on-site potential difference, Δz. Our findings of high controllability of the spin and valley transport in such a FNF silicene junction may improve the performance of nano-electronics and spintronics devices.

  8. Alkaline denaturation of dentin. A simple way to isolate human tooth enamel for electron spin resonance dosimetry

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) of tooth enamel is a recently developed method for the retrospective dose estimation of human radiation exposures. The assay requires isolation of enamel from dentin, which is difficult because the boundary between enamel and dentin is not easily discernible. Here we describe a simple method for isolating enamel by alkaline denaturation of dentin. The method requires 4 weeks, but scratching of the denatured and hence softened dentin is needed only once a week. Above all, no special skill is required. We found that the alkaline treatment did not cause deterioration of the ESR signal recorded in enamel exposed to 2 Gy of γ-rays prior to its isolation. The assay is particularly suited for teeth containing many cracks that were generated during long-term storage after extraction of the teeth. Such teeth tend to disintegrate during enamel isolation processes, which poses difficulties to isolate enamel mechanically from individual small pieces. (author)

  9. Analysis of dose in teeth for estimation of effective dose by the electron spin resonance (ESR) dosimetry using dental enamels

    International Nuclear Information System (INIS)

    Dose in teeth was studied to develop a method that can predict effective dose from results by the Electron Spin Resonance (ESR) dosimetry using dental enamels for external photon exposure. Absorbed dose in teeth and effective dose were calculated by the Electron Gamma Shower Code Version 4 (EGS4). In the Monte Carlo calculations, a region for teeth was newly added to a mathematical human model. Experiments were carried out with a head phantom, which is made of tissue equivalent materials. ESR dosimetry was made with dental enamels irradiated at teeth-part in the head phantom. The absorbed dose in a mouth was also measured with TLDs exposed to gamma rays as the teeth. The Monte Carlo calculation and the experiment gave a quantitative relationship between absorbed dose in teeth and effective dose. The obtained data are considered to be useful for the retrospective individual dose assessment with ESR dosimetry using dental enamels. (author)

  10. Comparative study between the Spin-echo and 3-D fast imaging techniques in the Knee evaluation with magnetic resonance

    International Nuclear Information System (INIS)

    We have carried out a retrospective analysis of the results of magnetic resonance (MR) studies in 20 patients, comparing two different sequences. We compared a 2-D spin-echo (SE2D) sequence with a 3-D fast imaging with steady-state precession (FISP3D) sequence in the attempt to compare the reliability of each in the detection of knee injuries. Arthroscopy was employed as a control technique. Our study revealed no statistically significant difference between the two sequences, although the overall sensitivity for the detection of meniscal lesions was slightly greater with the FISP3D sequence; however, the reliability in the detection of ruptures of the posterior cruciate ligament is less with this sequence than with the SE2D sequence. Both sequences showed very low sensitivity in the detection of hyaline cartilage injuries. (Author) 14 refs

  11. Magnetic resonance force microscopy in fast-relaxing spins using a frequency-modulation mode detection method

    International Nuclear Information System (INIS)

    We describe a magnetic resonance force microscopy experiment carried out using both a fast-relaxing spin system and a frequency-modulation mode detection method, presenting a validation of the measured signal and sensitivity. The detection method applied along with a self-excited cantilever oscillation worked stably without any serious interference due to spurious cantilever excitation despite application of first-harmonic microwave modulation, and thereby successfully created almost the maximum available signal. The signal could be measured without distortion while the magnetic field was swept at a rate of 1.9 G s-1. The measured sensitivity approached the thermal noise limit of the cantilever with a high quality factor. The experimental results for both signal and noise were in good agreement with theoretical predictions

  12. Thermal evolution process of organic free radicals in γ-ray irradiated pepper studied by electron spin resonance

    International Nuclear Information System (INIS)

    An increase behavior of radicals in black pepper induced by the γ-ray irradiation was analyzed using electron spin resonance (ESR) spectroscopy. A sharp signal at g=2.0, observed in the ESR spectrum of pepper due to organic free radicals produced by γ-ray irradiation, increased exponentially in the early stage of heating procedure and then leveled off at a certain value. The increase behavior was analyzed following to a first order differential equation, and obtained a general solution under the restrictions of initial and boundary conditions. Based on the general solution, we carried out the functional prediction using the nonlinear least squares method, and determined a rigorous solution for the time constant of the radical increase. (author)

  13. Thermal decay process of organic free radicals in γ-ray irradiated pepper as studied by electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    Using electron spin resonance (ESR) spectroscopy, we revealed the thermal decay process of radicals as induced by γ-ray irradiation on pepper. Upon irradiation, the satellite signals were newly generated at the symmetric positions of the organic free radical, i.e., the g=2.0 signal. By heat treatment, the satellite signals decreased exponentially to heating duration. The ESR signal of the pepper heated for more than 10 min was essentially the same as that before irradiation. In order to evaluate the radical decay during heating, we derived a time-dependent master equation. Based upon the general solution of the equation, we evaluated the time constant of the radical decay through the nonlinear least squares method. (author)

  14. Magnetic Resonance Microscopy Contribution to Interpret High-Resolution Magic Angle Spinning Metabolomic Data of Human Tumor Tissue

    Directory of Open Access Journals (Sweden)

    M. Carmen Martínez-Bisbal

    2011-01-01

    Full Text Available HRMAS NMR is considered a valuable technique to obtain detailed metabolic profile of unprocessed tissues. To properly interpret the HRMAS metabolomic results, detailed information of the actual state of the sample inside the rotor is needed. MRM (Magnetic Resonance Microscopy was applied for obtaining structural and spatially localized metabolic information of the samples inside the HRMAS rotors. The tissue was observed stuck to the rotor wall under the effect of HRMAS spinning. MRM spectroscopy showed a transference of metabolites from the tissue to the medium. The sample shape and the metabolite transfer after HRMAS indicated that tissue had undergone alterations and it can not be strictly considered as intact. This must be considered when HRMAS is used for metabolic tissue characterization, and it is expected to be highly dependent on the manipulation of the sample. The localized spectroscopic information of MRM reveals the biochemical compartmentalization on tissue samples hidden in the HRMAS spectrum.

  15. Possibilities of thermoluminescence dating and electron spin resonance dating within the Institute of Geological and Nuclear Sciences

    International Nuclear Information System (INIS)

    The Nuclear Sciences Review suggested that we establish thermoluminescence dating in this Institute. The technique is reviewed and it is suggested that electron spin resonance (ESR), a parallel technique would be more appropriate. The Institute of Geological and Nuclear Sciences Limited already has experience in the technique and has published in the field. Equipment is available on campus. The main use could be for dating quartz, perhaps as old as 1 Ma. However the technique is labour intensive and expensive; it is also subject to more uncertainties than existing techniques in use here. It is recommended that it be used, but as a technique often requiring support and confirmation from other techniques. Usually it will be useful in the age range 0-350 ka, about the same as U/Th series dating. Commercial application of thermoluminescence (and hence probably ESR as well) would not be profitable because of the subsidised analysis offered in the Wollongong University Laboratory. (author) 13 refs

  16. Studies on electronic spectrum and electron spin resonance of vanadium (IV) complexes with organophosphorus compounds and high molecular weight amines

    International Nuclear Information System (INIS)

    In the extraction of vanadium (IV) from aqueous solutions containing hydrochloric acid and/or a mixture of hydrochloric acid and lithium chloride by bis(2-ethylhexyl) hydrogenphosphate (DEHPA; HX), trioctylmethylammonium chloride (Aliquat-336), trioctylamine (TOA), trioctylphosphine oxide (TOPO) and tributyl phosphate (TBP), the complexes formed in the organic phases have been examined by spectrophotometry and electron spin resonance spectroscopy. It is found that in the extraction by DEHPA, the vanadium in the organic phase exists as the monomeric species, VO(X2H)2, or the polymeric one, (VOX2)sub(n), and that in the extractions by Aliquat-336, TOA, TOPO, and TBP, tetravalent vanadium complexes are stable in the organic phases extracted from a mixed solution of hydrochloric acid and lithium chloride, while complexes containing pentavalent vanadium and VOV4+ ions are formed in the organic phases extracted from hydrochloric acid solutions. (author)

  17. Noninvasive measurements of regional cerebral perfusion in preterm and term neonates by magnetic resonance arterial spin labeling

    DEFF Research Database (Denmark)

    Miranda Gimenez-Ricco, Maria Jo; Olofsson, K; Sidaros, Karam

    2006-01-01

    Magnetic resonance arterial spin labeling (ASL) at 3 Tesla has been investigated as a quantitative technique for measuring regional cerebral perfusion (RCP) in newborn infants. RCP values were measured in 49 healthy neonates: 32 preterm infants born before 34 wk of gestation and 17 term...... higher (p < 0.0001) than in cortical gray matter (19 and 16 mL/100 g/min) and white matter (15 and 10 mL/100 g/min), both in preterm neonates at term-equivalent age and in term neonates. Perfusion was significantly higher (p = 0.01) in the preterm group than in the term infants, indicating that RCP may...... be influenced by developmental and postnatal ages. This study demonstrates, for the first time, that noninvasive ASL at 3T may be used to measure RCP in healthy unsedated preterm and term neonates. ASL is, therefore, a viable tool that will allow serial studies of RCP in high-risk neonates...

  18. A theoretical investigation of Ferromagnetic Resonance Linewidth and damping constants in coupled trilayer and spin valve systems

    International Nuclear Information System (INIS)

    The ferromagnetic resonance intrinsic field linewidth ΔH is investigated for a multilayer system such as a coupled trilayer and a spin valve structure. The magnetic coupling between two ferromagnetic layers separated by a nonmagnetic interlayer will be described by the bilinear J1 and biquadratic J2 coupling parameters. The interaction at the interface of the first ferromagnetic layer with the antiferromagnetic one is account for by the exchange anisotropy field, HE. A general formula is derived for the intrinsic linewidth ΔH. The explicit dependence of ΔH with HE, J1 and J2 will be highlighted. Analytical expressions for each mode field linewidth are found in special cases. Equivalent damping constants will be discussed

  19. Critical Electron-Paramagnetic-Resonance Spin Dynamics in NiCl2

    DEFF Research Database (Denmark)

    Birgeneau, R.J.; Rupp, L.W.; Guggenheim, H.J.;

    1973-01-01

    We have studied the critical behavior of the electron-paramagnetic-resonance linewidth in the planar XY antiferromagnet NiCl2; it is found that the linewidth diverges like ξ∼(T-TN)-0.7 rather than ξ5/2 predicted by the current random-phase-approximation theory.......We have studied the critical behavior of the electron-paramagnetic-resonance linewidth in the planar XY antiferromagnet NiCl2; it is found that the linewidth diverges like ξ∼(T-TN)-0.7 rather than ξ5/2 predicted by the current random-phase-approximation theory....

  20. Few-second-long correlation times in a quantum dot nuclear spin bath probed by frequency-comb nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Waeber, A. M.; Hopkinson, M.; Farrer, I.; Ritchie, D. A.; Nilsson, J.; Stevenson, R. M.; Bennett, A. J.; Shields, A. J.; Burkard, G.; Tartakovskii, A. I.; Skolnick, M. S.; Chekhovich, E. A.

    2016-07-01

    One of the key challenges in spectroscopy is the inhomogeneous broadening that masks the homogeneous spectral lineshape and the underlying coherent dynamics. Techniques such as four-wave mixing and spectral hole-burning are used in optical spectroscopy, and spin-echo in nuclear magnetic resonance (NMR). However, the high-power pulses used in spin-echo and other sequences often create spurious dynamics obscuring the subtle spin correlations important for quantum technologies. Here we develop NMR techniques to probe the correlation times of the fluctuations in a nuclear spin bath of individual quantum dots, using frequency-comb excitation, allowing for the homogeneous NMR lineshapes to be measured without high-power pulses. We find nuclear spin correlation times exceeding one second in self-assembled InGaAs quantum dots--four orders of magnitude longer than in strain-free III-V semiconductors. This observed freezing of the nuclear spin fluctuations suggests ways of designing quantum dot spin qubits with a well-understood, highly stable nuclear spin bath.