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.
Multifrequency spin resonance in diamond
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.
Spin gravitational resonance and graviton detection
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.
Simple classical approach to spin resonance phenomena
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...
Observation of a hybrid spin resonance
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
Fermi liquid theory of resonant spin pumping
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 ...
Towards Long Range Spin-Spin Interactions via Mechanical Resonators
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.
Theoretical foundations of electron spin resonance
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
Composite spin-1 resonances at the LHC
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.
Spin-3/2 Pentaquark Resonance Signature
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
Light quark spin symmetry in Zb resonances?
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.
Magnetic-resonance force microscopy measurement of entangled spin states
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
Magnetic Resonance Force Microscopy Measurement of Entangled Spin States
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.
Electron spin resonance identification of irradiated fruits
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)
Electron-Spin Resonance in Boron Carbide
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.
Cavities for electron spin resonance: predicting the resonant frequency
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.
Spin resonance strength calculation through single particle tracking for RHIC
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.
Neutron Resonance Spin Determination Using Multi-Segmented Detector DANCE
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-.
Overcoming Intrinsic Spin Resonances with an rf Dipole
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
Resonance fluorescence and electron spin in semiconductor quantum dots
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.)
Current-induced spin torque resonance of a magnetic insulator
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.
Nuclear spin magnetic resonance force microscopy using slice modulation
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
Spin-flip induction of Fano resonance upon electron tunneling through atomic-scale spin structures
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.
Simple analytic formula for the strength of spin depolarizing resonance
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
Spin tests of intermediate resonances in doubly radiative quarkonium decays
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
Spin injection and detection by resonant tunneling structure
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...
Induction-detection electron spin resonance with spin sensitivity of a few tens of spins
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
Induction-detection electron spin resonance with spin sensitivity of a few tens of spins
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.
PREFACE: Muon spin rotation, relaxation or resonance
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
Numerical simulation study on spin resonant depolarization due to spin-orbit coupling
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.
Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator
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.
Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator
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.
Electron spin resonance investigations on polycarbonate irradiated with U ions
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
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.
Micromagnetic understanding of stochastic resonance driven by spin-transfertorque
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.
Telling the spin of the di-photon resonance
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.
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.
Double-spin-flip resonance of rhodium nuclei at positive and negative spin temperatures
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...
Double-spin-flip resonance of rhodium nuclei at positive and negative spin temperatures
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...
Study of spin resonances in the accelerators with snakes
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
Spin injection in a ferromagnet/resonant tunneling diode heterostructure
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.
Electron spin resonance study of NiO antiferromagnetic nanoparticles
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
Matrix Formalism for Spin Dynamics Near a Single Depolarization Resonance
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.
Reaching the quantum limit of sensitivity in electron spin resonance
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.
Strong coupling of paramagnetic spins to a superconducting microwave resonator
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.
Resonant tunneling diode with spin polarized injector
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...
Comments on ``Spin Connection Resonance in Gravitational General Relativity''
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.
Diphoton excess in phenomenological spin-2 resonance scenarios
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.
Diphoton excess in phenomenological spin-2 resonance scenarios
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.
Spin-resolved Fano resonances induced large spin Seebeck effects in graphene-carbon-chain junctions
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.
Spin-resolved Fano resonances induced large spin Seebeck effects in graphene-carbon-chain junctions
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.
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
Spin isovector giant resonances in (n,p) reactions
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
Spin-(3/2) pentaquark resonance signature in lattice QCD
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
Spin-3/2 pentaquark resonance signature in lattice QCD
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.)
Field integral correction in neutron resonance spin echo
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
Resonant Spin Wave Excitation by Terahertz Magnetic Near-field Enhanced with Split Ring Resonator
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.
Enhancement of Spin-transfer torque switching via resonant tunneling
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.
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.
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)
Randomized benchmarking of quantum gates implemented by electron spin resonance
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.
Analysis and approximations for crossing two nearby spin resonances
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.
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...
RESPECT: Neutron Resonance Spin-Echo Spectrometer for Extreme Studies
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...
Spin injection in n-type resonant tunneling diodes
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.
Spin dependent electron transport through a magnetic resonant tunneling diode
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...
A capacitive probe for Electron Spin Resonance detection
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.
Nuclear Tuning and Detuning of the Electron Spin Resonance in a Quantum Dot
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.
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.
Electron-spin resonance and Rabi oscillations on helium nanodroplets
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)
Photo-production of Nucleon Resonances and Nucleon Spin Structure Function in the Resonance Region
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.
Force detected electron spin resonance at 94 GHz.
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
Modeling the neutron spin-flip process in a time-of-flight spin-resonance energy filter
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.)
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
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.
Splitting of the Dipole and Spin-Dipole Resonances
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.
Random spin signal in magnetic resonance force microscopy
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
Electron spin resonance of Er3+ in YBiPt
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.)
Electron spin resonance as a method of dating
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)
Harmonic trap resonance enhanced synthetic atomic spin-orbit coupling
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.
Determination of the spin channel contributions to the yttrium p-resonances
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
Disorder effect of resonant spin Hall effect in a tilted magnetic field
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...
Resonant harmonic generation and collective spin rotations in electrically driven quantum dots
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...
Resonant spin-flavour precession of neutrinos and pulsar velocities
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
Spin-selected resonant tunneling through a magnetic-controlled diode
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
Spin-selected resonant tunneling through a magnetic-controlled diode
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.
Understanding and controlling spin-systems using electron spin resonance techniques
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
Electron spin resonance in the study of diamond
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)
Direct-decay properties of charge-exchange spin giant resonances
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.
Spin-locked internally resonant ion cyclotron excitation for magnetic resonance trapped ions
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.
Spin-locked internally resonant ion cyclotron excitation for magnetic resonance trapped ions
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
Electron Spin Resonance and Related Phenomena in Low-Dimensional Structures
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
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
Magnetic resonance force microscopy with a single spin S>1/2
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.
Identification of irradiated chicken meat using electron spin resonance spectroscopy
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)
Electron spin resonance intercomparison studies on irradiated foodstuffs
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
Electron Spin Resonance Imaging Utilizing Localized Microwave Magnetic Field
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.
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.
Nucleon Spin Structure Functions in the Resonance Region and the Duality
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.
Off-Resonant Manipulation of Spins in Diamond via Precessing Magnetization of a Proximal Ferromagnet
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...
Light-free magnetic resonance force microscopy for studies of electron spin polarized systems
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
Spin Transfer of Quantum Information between Majorana Modes and a Resonator
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.
Hydrogen in group III nitrides, studied by muon spin resonance
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)
Controlling the Spin Polarization of the Electron Current in a Semimagnetic Resonant-Tunneling Diode
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...
Study of f electron correlations in nonmagnetic Ce by means of spin resolved resonant photoemission
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.
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.
Disentangling the Spin-Parity of a Resonance via the Gold-Plated Decay Mode
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.
Detection of single electron spin resonance in a double quantum dota)
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.
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.
Identification of irradiated rice noodles by electron spin resonance spectroscopy
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.
Mechanical detection of electron spin resonance beyond 1 THz
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.
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.
Spin-dependent current in resonant tunneling diode with ferromagnetic GaMnN layers
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.
Spin-dependent current in resonant tunneling diode with ferromagnetic GaMnN layers
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.
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 ...
Electron Spin Resonance of Tetrahedral Transition Metal Oxyanions (MO4n-) in Solids.
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)
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)
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.
Driving and detecting ferromagnetic resonance in insulators with the spin Hall effect.
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.
Voltage-Controlled Spin Selection in a Magnetic Resonant Tunnelling Diode
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...
Resonant Neutrino Spin-Flavor Precession and Supernova Nucleosynthesis and Dynamics
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 \
Using Markov models to simulate electron spin resonance spectra from molecular dynamics trajectories
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...
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.
Measurement of the Spin of the $\\Xi(1530)$ Resonance
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.
Energy harvesting using rattleback: Theoretical analysis and simulations of spin resonance
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.
Quantum Measurement of a Single Spin using Magnetic Resonance Force Microscopy
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.
Voltage-controlled spin selection in a magnetic resonant tunneling diode.
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
Phonon-magnon resonant processes with relevance to acoustic spin pumping
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.
Resonant Scattering off Magnetic Impurities in Graphene: Mechanism for Ultrafast Spin Relaxation
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.
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.
Baseband Detection of Bistatic Electron Spin Signals in Magnetic Resonance Force Microscopy (MRFM)
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...
Spin-filter device based on the Rashba effect using a nonmagnetic resonant tunneling diode.
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
Observation of vacuum-enhanced electron spin resonance of levitated nanodiamonds
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...
Measurement of a mixed-spin-channel Feshbach resonance in 87 Rb
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.
Current-induced resonant depinning of a transverse magnetic domain wall in a spin valve nanostrip
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.
Intrinsic oscillations of spin current polarization in a paramagnetic resonant tunneling diode
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...
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...
Quantum size effects on spin-tunneling time in a magnetic resonant tunneling diode
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...
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.
Current-Induced Spin-Torque Resonance of Magnetic Insulators
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
Radiosterilization dosimetry by electron-spin resonance spectroscopy. Cefotetan
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
Probing dynamics of a spin ensemble of P1 centers in diamond using a superconducting resonator
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
Spin measurements for 147Sm+n resonances: Further evidence for non-statistical effects
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...
Persistent quantum resonance transition in spin Hall transport
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.
Resonant and time-resolved spin noise spectroscopy
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.
Soft spin dipole giant resonances in 40Ca
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.
Spin and charge thermopower of resonant tunneling diodes
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
Spin and charge thermopower of resonant tunneling diodes
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.
Soft spin-dipole resonances in 40Ca
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.
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...
Intrinsic oscillations of spin current polarization in a paramagnetic resonant tunneling diode
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.
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.
Hysteresis loops of spin-dependent electronic current in a paramagnetic resonant tunnelling diode
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)
Hysteresis loops of spin-dependent electronic current in a paramagnetic resonant tunnelling diode
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.
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 ...
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.
Performance test of neutron resonance spin echo at a pulsed source
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
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...
Radiation-sterilized bone grafts evaluated by electron spin resonance technique and mechanical tests
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
Effect of Electric and Magnetic Fields on Spin Dynamics in the Resonant EDM Experiment
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.
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...
Spin-wave resonance in the FeBr2 magnetic thin film
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)
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
Solid-state nuclear-spin quantum computer based on magnetic resonance force microscopy
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
Single-Spin Measurement and Decoherence in Magnetic Resonance Force Microscopy
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.
Solid-State Nuclear Spin Quantum Computer Based on Magnetic Resonance Force Microscopy
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.
Estimation of the Postmortem Duration of Mouse Tissue by Electron Spin Resonance Spectroscopy
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...
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
The Spin Structure of the Proton in the Resonance Region
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.
Spin measurements for 147Sm+n resonances: Further evidence for nonstatistical effects
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
On The $Q^2$ Dependence of The Spin Structure Function In The Resonance Region
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.
Modified approach to single-spin detection using magnetic resonance force microscopy
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
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
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.
Wave function collapses in a single spin magnetic resonance force microscopy
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
Wave function collapses in a single spin magnetic resonance force microscopy
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
CONDITIONS OF PASSAGE AND ENTRAPMENT OF TERRESTRIAL PLANETS IN SPIN-ORBIT RESONANCES
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.
A new Skyrme energy density functional for a better description of spin-isospin resonances
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.
A new Skyrme energy density functional for a better description of spin-isospin resonances
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
A new Skyrme energy density functional for a better description of spin-isospin resonances
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.
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
Ferromagnetic resonance dispersion relation of spin valve systems
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.
Magnetic defects in chemically converted graphene nanoribbons: electron spin resonance investigation
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.
Experimental and theoretical study of conduction electron spin resonance in aluminum
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
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
Photoelectric detection of electron spin resonance of nitrogen-vacancy centres in diamond
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
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...
A point of view about identification of irradiated foods by electron spin resonance
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
Double Barrier Resonant Tunneling in Spin-Orbit Coupled Bose—Einstein Condensates
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
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)
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.
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
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.
On the spin and parity of a single-produced resonance at the LHC
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.
High precision beam momentum determination in a synchrotron using a spin resonance method
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.
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.
Epitaxial MnAs Films Studied by Ferromagnetic and Spin Wave Resonance
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.
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.
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 ...
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
One-loop effects from spin-1 resonances in Composite Higgs models
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.
Resonance-inclined optical nuclear spin polarization of liquids in diamond structures
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...
Thermal mixing in multiple-pulse nuclear quadrupole resonance spin-locking
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
Signal-background interference for a singlet spin-0 digluon resonance at the LHC
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.
Analysis of the transient response of nuclear spins in GaAs with/without nuclear magnetic resonance
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.
Isotope effect on the spin resonance of boron in silicon
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.
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
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.
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
Electron spin resonance of radicals and metal complexes
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
Electron spin resonance of copper labelled myoglobin crystals
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+
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...
Spin Vortex Resonance in Non-planar Ferromagnetic Dots
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.
On Mercury's entrapment into the 3:2 spin-orbit resonance
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.
Towards achieving strong coupling in three-dimensional-cavity with solid state spin resonance
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.
Magnetic field dependence of the neutron spin resonance in CeB6
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.
The Onset Of Resonance In Two-Immiscible Fluids Inside A Spinning And Coning Cylinder
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...
Pion-nucleus spin-flip strength at low and resonance energies
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
Electron spin resonance study of Na_{1-x}Li_xV_2O_5
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...
Spin-orbit driven ferromagnetic resonance: a nanoscale magnetic characterisation technique
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
The giant dipole resonance at high spin and moderate temperature
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.)
High-pressure magic angle spinning nuclear magnetic resonance.
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
High-pressure Magic Angle Spinning Nuclear Magnetic Resonance
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.
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.
Spin–orbit interaction in bent carbon nanotubes: resonant spin transitions
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)
Non-resonant parametric restoration of microwave spin-wave signals in YIG films
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.
Estimation of the Postmortem Duration of Mouse Tissue by Electron Spin Resonance Spectroscopy
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.
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.
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.
Controlling nuclear spin exchange via optical Feshbach resonances in ${}^{171}$Yb
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...
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.
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
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.
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
Optical rotation and electron spin resonance of an electro-optically active polythiophene
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.
Spin-mixed doubly excited resonances in Ca and Sr spectra
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.
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.
Magnetic field splitting of the spin-resonance in CeCoIn5
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.
Magnetic field splitting of the spin resonance in CeCoIn5.
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
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.
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.
OBTAINING THE CRITICAL DRAW RATIO OF DRAW RESONANCE IN MELT SPINNING FOR POWER LAW POLYMER FLUIDS
无
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.
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)
Electron doping evolution of the neutron spin resonance in NaFe$_{1-x}$Co$_{x}$As
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 ...
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.
Spin filter effect at room temperature in GaN/GaMnN ferromagnetic resonant tunnelling diode
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.
Current-driven, electrically detected ferromagnetic resonance in electrodeposited spin valves
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.
Integer spin resonance crossing at VEPP-4M with conservation of beam polarization
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.
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
Electron Spin Resonance Spectroscopy: Application to Proof of Structure of Organic Ketones.
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