Search

The CMS magnets are fully tested, where it has reached its nominal field of 4T without any problem related to the magnet itself. Special emphasis is put on the results of phenomena that are related to the induced fast discharges, such as coupling and quench-back effects.

The ferroelectric and magnetic properties of Yb([Mn.sub.1-x][Al.sub.x])[O.sub.3] are examined. The Al substitution resulted in reduced super exchange interaction with Yb and Mn as a result of disordering of a [Mn.sup.3+] triangle spin structure.

The proton-driven [super 13]C spin diffusion (PDSD) experiment with proton recoupling (DARR) is described for determining the protein structure. The relationship between the internuclear distances and cross-peak intensities in the spectra is examined.

The effects of the carrier envelope phase (CEP) on the efficiency of several all-optical poling with the third- and higher-order nonlinear processes are studied. The results show that the second harmonic (SH) intensity highly depends on the sample thickness.

The importance of the tripodal supporting ligand in the tuning of the spin-state energetics and spin-crossover behavior of the pseudotetrahedral cobalt(III)-imido complexes is described. The results prove that an iron tripodal species exhibit a high-spin ground state.

Bound state calculations were performed on the Br([super 2]P)-HCN complex with HCN kept linear and CN bond frozen and all adiabatic states were included and spin-orbit coupling was taken into account. Two linear isomers were found, Br-HCN and Br-NCH with both exhibiting similar binding energies and also the ground electronic state of the two isomers was established which is affected by the electrostatic interaction and strong spin-orbital coupling in Br.

The study explains the properties of trans-haloarylbis(triphenylphosphine)nickel(II), an air- and moisture-stable Ni(II)-([sigma]-aryl) complex. The complex is found to act as a facile and efficient catalyst precursor for the carbon-nitrogen coupling reactions.

Modifications of the scaled second-order perturbation corrections to configuration interaction with single substitutions are suggested. There two approaches described and their accuracy is found to be comparable which arises from a strong correlation between the same-spin and the opposite spin portions of the excitation energy terms.

The restrictions of [pi]-orbital interactions (GOR) was developed to estimate stabilization energies fro aromatic molecules of various types. The GOR can isolate the [pi] system of a specific group from those of other groups and a substitute effect can be partitioned into the conjugative and inductive parts indicating that the conjugative effect plays the predominant role in determining substituent effects.

Spin state selective detection of single quantum transitions using multiple quantum coherence were employed to simplify the analyses of complex NMR spectra. It was shown that it is possible to separate the subspectra of a homonuclear dipolar coupled spin system on the basis of the spin states of the coupled heteronuclei by multiple quantum (MQ)-single quantum (SQ) correlation experiments.

Single-molecule magnets with larger spins are generated when the carboxylate ligation is altered by the oxime moiety. The oxime moiety is twisted, due to which there is structural distortion to the core of the molecule that enhances the magnetism of the molecule.

The preparation of a series of trigonal bipyramidal (TBP) cyanide-bridged complexes containing [Fe.sup.11] ions in the equatorial positions is described. The physical properties of these pentanuclear clusters are found to mimic properties measured for Persian blue (PB) and its analogues.

A detailed study of a triply interpenetrating three-dimensional (3D) spin crossover (SC) coordination polymer [Fe[(4ditz).sub.3]][(P[F.sub.6]).sub.2]*solv is reported whose magnetic properties could be tuned by inclusion of a different solvent. Both methanol and ethanol solvents show an abrupt two-step spin crossover from low spin (S = 0) to high spin (S = 2) with the methanolate curve lying 7 K higher and showing a small hysteresis.

The characteristics of a future-generation all-metal device fabricated with minimum feature size f of 50nm are analyzed. The thermodynamic formalism of Johnson and Silsbee is used to study details of charge and spin transport at the F / N interface and to understand the limits of the fractional polarization of injected current.

Electronic transport through II-VI semiconductors resonant-tunneling structures containing diluted magnetic impurities is demonstrated. A giant Zeeman splitting in the presence of a moderately low magnetic field arises due to the exchange interaction between the conduction electrons and the impurities and experimental data that are presented shows that devices can work as spin filters when the quantum well is magnetic.

The various injection contact technologies that are reported are summarized and their potential for practice device applications in terms of electrical efficiency is assessed. The results demonstrate that the key requirement to observe a significant magnetoresistence is a correct design of the semiconductor channel such that the spin polarization that is provided by the magnetic contacts can be preserved.

A spin interference effect in small arrays of mesoscopic InGaAs rings, which is the time reversal Aharonov-Casher effect, is presented. Results show evidence for electrical manipulation of the spin precession angle in an InGaAs 2-D electron gas channel.

The problem of spin transport in a nonmagnetic channel between source and drain is described. Methods to solve these problems are mentioned and the question as to why the transformation of spin information into large electrical signal is more easily achieved with carbon nanotubes than with semiconductors is discussed.

The synthesis, physical and spectroscopic properties of a series of metal complexes bridged by the redox-active chloranilate ligand are presented. The effects of Heisenberg spin exchange and a quantitative ligand-field analysis have indicated that the transitions are the consequences of exchange interactions in both the ground- and excited-state manifolds of the compounds.

Two tricyanometallate precursors with low spin [Fe.sup.III] center are synthesized and characterized. The results have shown that the mononuclear compounds are the versatile building blocks for assembling new cyanide-bridged heterometallic high-spin clusters with interesting magnetic properties.

A report is presented on ultrahigh resolution studies of the bound exciton states associated with the shallow acceptor B and the shallow donor P in highly enriched [super 28]Si by using a tunable single frequency laser to perform photoluminescence exciton spectroscopy. The [super 31]P nuclear spin populations are modified by optical methods and the donors in specific electronic and nuclear spin configurations are selectively photoionized.

The different methods of gating and nanostructure fabrication of modulation doped PbTe quantum wells are described. The analysis has shown that PbTe quantum wires acts as efficient local spin-filters, in which the spin polarized current is carried by a large number of wire modes.

The ligand field and the spin-orbit coupling for the [d.sup.5] configuration ion in a trigonal ligand field, the local distortion structure of the [(Mn[O.sub.6]).sup.10-] coordination complex for [Mn.sup.2} ions doped into CaC[O.sub.3], are investigated by diagonalizing the complete energy matrices of the electron-electron repulsion. The results show a microscopic origin of various ligand field parameters that are used for the interpretation of electron paramagnetic resonance and optical absorption spectra for [Mn.sub.2} ions in CaC[O.sub.3] have agreed well with the experimental findings.

An empirical study is conducted to determine the influence of low energy, inert gas ion assistance during the deposition of a Ta/NiFe/Co/Cu/Co/FeMn/Cu spin valve structure. The outcomes confirm the atomistic simulation predictions.

The pillar-shaped spin valves with the magnetization of the reference layer being pinned perpendicularly to the easy axis of the free layer was used to show that spin-transfer-induced microwave emission could be obtained at exactly zero applied magnetic field and in its vicinity. The ability to get satisfactory microwave emission without needing bulky magnetic field sources is observed to arise from a small nonvanishing field-like term in the current-induced torque which might be used to design the submicron microwave sources.

The results of micromagnetic simulations of magnetic tunnel junctions (MTJs) patterned from thin films consisting of CoFe(8 nm)/[Al.sub.2][O.sub.3](0.8 nm)/Py(4 nm) with an elliptical cross section (90 * 35 n[m.sup.2]), where the CoFe and the Py are the fixed layer (PL) and the free layer (FL), respectively is presented. The results reveal that the switching mechanism does not change qualitatively by introducing a misalignment while the switching mechanism changes qualitatively when a nonideal shape is introduced.

Polarized optical microscopy, differential scanning calorimetry and powder X-ray analysis are used to characterize the physical properties and synthesize the iron(II) compounds. It is found that the iron(II) compounds can undergo spin-crossover and photoinduced spin transition as well as have liquid-crystal properties all in a single molecule.

The detection of spin noise from paramagnetic molecules of [alpha], [gamma]-bisdiphenylene-[beta]-phenylallyl (BDPA) and the electron spin resonance spectra from ultrathin films of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and BDPA grown on Au(111) are reported. The results have helped in understanding the low statistical recurrence of the spin noise in the data set.

Micromagnetic computational spectral mapping is used to analyze the magnetic oscillation modes excited by either a microwave circularly polarized magnetic field or a spin polarized current flowing through Permalloy (Py) spin valves. Micromagnetic spectra mapping method is an adequate tool for describing the temporal evolution of the magnetization spatial patterns in nanostructures.

The spin drift-diffusion (SDD) theory is used to describe the spin-dependent transport across a pseudospin-valve structure, in which the spin relaxation effects are globally absorbed into the two effective branch resistances. Based on the two-current model it is found that the overall magnetoresistance (MR) is much more sensitive to the spin relaxation effect in the nonmagnetic (NM) layer compared to that in the ferromagnetic (FM) layers.

A comparative density functional theory (DFT) study of a series of neutral and negative ionic lithium and aluminum clusters doped with iodine atom is described. It is seen that the atom preserves the same position at [Li.sub.13] with and without the negative charge and [Li.sub.13] to vary its shape from prolate to oblate with changing spin state of [Li.sub.13]I.

Study is conducted to investigate the dipolar coupling effect in closely packed and isolates pseudo-spin-valve (PSV) nanowires. Study reveals marked changes in the magnetization reversal behavior due to the effect of interwire magnetostatic coupling when the spacer layer thickness is comparable to the edge-to-edge

Results from measuring the angular dependence of magnetoresistance (MR) on the [La.sub.0.7][Ca.sub.0.3]Mn[O.sub.3] (LCMO] biepitaxial step junctions (BSJs) obtained by depositing LCMO film onto SrTiO3(100) substrate partially buffered with a layer of anatase TiO2(001) is reported. The magnetudes of anisotropic magnetoresistance (AMR) suggest that the conventional spin-orbit coupling effect, though may explain the in-plane anisotropy is inadequate to account for the perpendicular anisotropy.

The degenerate electron exchange (DEE) reaction involving radical cations (RCs) of n-nonane, n-dodecane, and n-hexadecane in n-hexane solution is analyzed by using the method of time-resolved magnetic field effect in recombination fluorescence of spin-correlated radical ion pairs. The influence of the interaction between RC and a neutral molecule in an encounter complex on DEE rate constant is examined.

The assembly of trimetallic [Mn.sup.2} spin-frustrated phosphines by using ligands and how their diamagnetic [Mg.sup.2} analogues maintain their trimetallic structures in solution are examined. The solution [super 31]P{[super 1]H} NMR spectroscopy has revealed an unexpected 15 Hz coupling between phosphorous nuclei in these complexes and the density functional theory calculations have shown that this coupling occurs via a combined through-space, through-bond pathway.

A study is conducted to show that the perpendicular injection of a spin-polarized current into a magnetic thin film could induce the domain formation through the spin-transfer effect. The results verify that the spin-transfer effect may induce domain formation in a magnetic thin film while it is also suggested that when the spin-transfer effect is utilized to switch the nanopillar device, the formation may result in the incomplete magnetization switching.

The effects of the intense terahertz laser field and the spin-orbit coupling on single spin in a quantum dot are investigated. The laser field and the spin-orbit coupling could strongly affect the electron density of states and could excite a magnetic moment.

The influence of the capping layer thickness on the magnetocurrent in the spin-value photodiode is investigated. The results have indicated that there is an optimum thickness to maximize the magnetocurrent (MC) of the device.

Azide-bound, two M(II) [M=Mn (1), Ni(2)] monomers capped by 5-methylpyrazole, resulting in 2D supramolecular assemblies formed by hydrogen bonds and [pi]-[pi] contacts and a terephthalate (tp)-bridged Co(II) compound (3) with a 2D sheet structure built by covalent and noncovalent bonds was prepared. Intra- and interchain hydrogen bonds are responsible for the presence of two types of capping ligands in the same coordination sphere and for 3 weak antiferromagnetic interactions through tp are present.

Spin relaxation under identical Dresslhaus and Rashba coupling in GaAs quantum wells is studied in both the traditional collinear statistics. It is shown that there is only marginal difference between the spin relaxation times obtained from these two different statistics.

A study of hyperconjugative and electrostatic interactions that effect the (super 1)J(sub CH) spin-spin coupling constants (SSCCs) are conducted from both theoretical and experimental points of view is presented. A qualitative model is used to predict how the former affect such SSCCs, while electrostatic interactions are modeled with a point charge placed in the vicinity of the corresponding sigma(sub CH) bond.

A theoretical study of the near gap electronic states of Si/Ge based multiple quantum well system composed of Si and Si (sub 1-x)Ge (sub x) alloys coherently grown on (001)-Si or SiGe substrates is presented. The calculations give an accurate description of the near gap experimental photoluminescence peaks.

This paper considers magnetization fluctuations (mag-noise) in current-perpendicular-to-plane (CPP) read sensors, due to either thermal fluctuations or spin-torque induced instability. The former are relevant to both tunneling (TMR) and giant-magnetoresistance (GMR) devices, the latter a potentially more serious limitation most relevant to all-metal GMR sensors. Discussion of thermal mag-noise is here treated by micromagnetic simulation. Discussion of spin-torque instability includes analytical modeling combined with experimental measurements. Index Terms--Current-perpendicular-to-plane, giant magnetoresistance, read head, spin-torque.

Relativistic effective core potentials are used to describe the inner shells of both the Te and O atoms. The energetic order of the electronic states in TeO appears to be very similar to that observed for the isovalent O2 molecule, but the Rydberg valence-mixing effects that are so prominent in the latter's spectrum are totally absent in TeO.

The element-free Galerkin-finite element (EFG-FE) coupling method, combined with the linear mathematical programming technique, is utilized to solve two-dimensional elastoplastic contact problems. Two discretized models for an elastic cylinder contacting with a rigid plane are used to investigate the boundary effects in a contact problem when using the EFG-FE coupling method under symmetric conditions. The influences of the number of Gauss integration points and the size supporting the weight function in the meshless region on the contact pressure and stress distributions are studied and discussed by comparing the numerical results with the theoretical ones. Furthermore, the elasto-plastic contact problems of a smooth cylinder with a plane and a rough surface with a plane are analyzed by means of the EFG-FE method and different elasto-plasticity models. [DOI: 10.1115/1.1843134]

Subpicosecond transient absorption studies are reported for a set of Rhodobacter (R.) capsulatus bacterial photosynthesis reaction centers (RCs) designed to probe the origins of the unidirectionality of charge separation through one of two electron transport chains in the native pigment-protein complex. The result states an upper limit of V(sub L)(super 2)/V(sub M)(super 2) less than or equal to 4 for the contribution of the electronic coupling elements to the relative rates of electron transfer to the L versus M sides of the wild-type RC.

The influence of coupling effects between constituents of system in near-field microscopy is studied in view of developed classical model of electromagnetic scattering from spherical nanoparticles. The study reveals the optical behavior of the spherical nanoparticles numerically, taking into account the electromagnetic coupling between all particles and the apertureless tip.

Networks of inhibitory neurons regulate synchrony during many physiological and pathological oscillations. To explore how these effects depend on cellular, network, and synaptic factors, we developed and validated a semisynthetic inhibitory network that approximates simultaneous activity in multiple neurons by using consecutive responses from single cells. We recorded from three types of neurons, each of which forms interconnected networks in vivo, but has unique intrinsic properties. In all three cell types, fast inhibitory coupling generated emergent gamma oscillations. By contrast, inhibitory coupling desynchronized slower, spindle-frequency responses specifically in thalamic reticular neurons. The emergent gamma-frequency synchronization was also specific to tonic input and did not occur during responses to phasic inputs. These results illustrate how particular features of inhibitory networks (e.g., cell or input type) contribute to their synchronizing or desynchronizing functions. They also demonstrate phenomena (emergent gamma oscillations) that occur robustly in multiple cell types and may thus be a generic feature of inhibitory networks throughout the brain. dynamic clamp | GABAA receptor | neocortex | synchrony | thalamus

Magnetic studies on the cages of cobalt(III) halides and 1,3 bis(pyrid-4ylthio)-prophan-2-one, which show the unexpectedly strong antiferromagnetic interactions mediated by the encapsulated anions Cl(minus) and Br(minus) are reported. It is found that the preparation of the series compounds indicate the suitable relationship between structures and tunarable reaction conditions and structural motifs vary according to the ligand conformations.