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2023-01-18
Probing electron-electron interaction along with superconducting fluctuations in disordered TiN thin films
Here, we demonstrate an interplay between superconducting fluctuations and electron-electron interaction (EEI) by low temperature magnetotransport measurements for a set of 2D disordered TiN thin films. While cooling down the sample, a characteristic temperature T* is obtained from the R(T) at which superconducting flu...
2301.07648v1
2023-02-08
Bioabsorbable WE43 Mg alloy wires modified by continuous plasma electrolytic oxidation for implant applications. Part II: degradation and biological performance
The corrosion, mechanical degradation and biological performance of cold-drawn WE43 Mg wires were analyzed as a function of thermo-mechanical processing and the presence of a protective oxide layer created by continuous plasma electrolytic oxidation (PEO). It was found that the corrosion properties of the non-surface-t...
2302.13778v1
2023-02-28
Quantifying interaction mechanism in infinite layer nickelate superconductors
The relationship between the long-range antiferromagnetic order in cuprates and the high-temperature superconductivity in these compounds represents unresolved, nearly four-decades long scientific problem. Because recently discovered nickelate superconductors are crystallographical counterparts of cuprates, many proper...
2302.14729v3
2023-03-11
Non-Fermi-Liquid Behavior of Superconducting SnH$_4$
We studied chemical interaction of Sn with H$_2$ by X-ray diffraction methods at pressures of 180-210 GPa. A previously unknown tetrahydride SnH$_4$ with a cubic structure (${fcc}$) exhibiting superconducting properties below ${T}$$_C$ = 72 K was obtained; the formation of a high molecular ${C2/m}$-SnH$_{14}$ superhydr...
2303.06339v2
2023-06-16
Tailoring defects and nanocrystal transformation for optimal heating power in bimagnetic $Co_yFe_{1-y}O@Co_xFe_{3-x}O_4$ particles
The effects of cobalt incorporation in spherical heterostructured iron oxide nanocrystals (NCs) of sub-critical size have been explored by colloidal chemistry methods. Synchrotron X-ray total scattering methods suggest that cobalt (Co) substitution in rock salt iron oxide NCs tends to remedy its vacant iron sites, offe...
2306.09684v1
2023-11-19
Discovery of Superconductivity and Electron-Phonon Drag in the Non-Centrosymmetric Weyl Semimetal LaRhGe$_3$
We present an exploration of the effect of electron-phonon coupling and broken inversion symmetry on the electronic and thermal properties of the semimetal LaRhGe$_3$. Our transport measurements reveal evidence for electron-hole compensation at low temperatures, resulting in a large magnetoresistance of 3000% at 1.8 K ...
2311.11402v2
2024-01-10
Droplet morphology-based wettability tuning and design of fog harvesting mesh to minimize mesh-clogging
Fog harvesting relies on intercepting atmospheric or industrial fog by placing a porous obstacle, e.g., a mesh and collecting the deposited water. In the face of global water scarcity, such fog harvesting has emerged as a viable alternative source of potable water. Typical fog harvesting meshes suffer from poor collect...
2401.05284v2
2024-02-18
Impact of the La2NiO4+δ oxygen content on the synaptic properties of the TiN/La2NiO4+δ/Pt memristive devices
The rapid development of brain-inspired computing requires new artificial components and architectures for its hardware implementation. In this regard, memristive devices emerged as potential candidates for artificial synapses because of their ability to emulate the plasticity of the biological synapses. In this work, ...
2402.11612v1
2024-03-12
Electronic and dynamical properties of cobalt monogermanide CoGe phases under pressure
We present the pressure dependence of the electronic and dynamical properties of six different CoGe phases: orthorhombic Cmmm, hexagonal P6/mmm and P$\bar{6}$2m, monoclinic C2/m, cubic P2$_{1}$3, and orthorhombic Pnma. Using first-principles DFT calculations and the direct force-constants method, we study the dynamical...
2403.07580v1
1996-07-09
Anomalous magnetic response of the valence-fluctuating compound YbInCu4
The exact solution of the spin one-half Falicov-Kimball model, with random hopping between the lattice sites, is used to explain the anomalous magnetic response of Yb-based valence-fluctuating intermetallic compounds. The anomalous behavior arises from an entropy-driven local-moment--nonmagnetic transition of unhybridi...
9607068v1
1996-09-27
Magnetoresistance in La(1-x)SrxCoO3 for 0.05 - x - 0.25
The dc resistivity, magnetoresistance and magnetic susceptibility of La(1-x)SrxCoO3 compounds have been investigated in the temperature range of 4K to 300K for magnetic fields up to 7 T. In the doping range studied (0.05 - x - 0.25) the electronic properties of the material exhibit a crossover from semiconducting to me...
9609274v1
1997-07-01
e-h Coherence and Charging Effects in Ultrasmall Metallic Grains
We consider a model for electron tunneling between a pair of ultrasmall metallic grains. Under appropriate circumstances, non-equilibrium final state effects can strongly enhance tunneling and produce electron-hole coherence between the grains. The model displays a quantum phase transition between a Coulomb blockaded s...
9707014v1
1997-07-18
Shearing the Vacuum - Quantum Friction
We consider two perfectly smooth featureless surfaces at T=0, defined only by their respective dielectric functions, separated by a finite distance, and ask the question whether they can experience any friction when sheared parallel to their interface. We find large frictional effects comparable to everyday frictional ...
9707190v2
1998-02-25
Magnetization Controlled Superconductivity in a Film with Magnetic Dots
We consider a superconducting film with Magnetic Dots Array (MDA) placed on it. Magnetic moments of these dots are supposed to be normal to the film and strong enough to create vortices in the superconducting film. Magnetic interaction between dots is negligible. Below the superconducting transition temperature of the ...
9802276v1
1998-03-28
Anomalous Hall Effect in Double Exchange Magnets
We investigate the possible origin of anomalous Hall effect in the CMR (colossal magnetoresistance) materials - the doped rare earth manganites - observed recently by Matl et al. It is demonstrated that the spin-orbit interaction in the double exchange model couples magnetization to the Berry phase associated with thre...
9803350v1
1998-07-13
Magnetoresistance of Epitaxial Fe Wires with Varied Domain Wall Structure
The low temperature negative domain wall (DW) contribution to the resistivity observed in expitaxial Fe microstructures has been investigated as a function of film thickness. The DW spin structure changes from Bloch to Neel-like with decreasing film thickness. Results suggest that an interplay between orbital effects i...
9807183v1
1998-09-02
Rolling friction of a hard cylinder on a viscous plane
The resistance against rolling of a rigid cylinder on a flat viscous surface is investigated. We found that the rolling-friction coefficient reveals strongly non-linear dependence on the cylinder's velocity. For low velocity the rolling-friction coefficient rises with velocity due to increasing deformation rate of the ...
9809053v1
1998-12-10
Electric field and potential around localized scatterers in thin metal films studied by scanning tunneling potentiometry
Direct observation of electric potential and field variation near local scatterers like grain boundaries, triple points and voids in thin platinum films studied by scanning tunneling potentiometry is presented. The field is highest at a void, followed by a triple point and a grain boundary. The local field near a void ...
9812167v1
1999-01-11
Effect of disorder on the Kondo behavior of thin Cu(Mn) films
We have studied the influence of disorder on the Kondo effect in thin films of Cu(Mn), i.e., Cu doped with a small amount of Mn. We find that the Kondo contribution to the resistivity is suppressed when the elastic mean-free-path, $\lambda$, is reduced. While this is qualitatively similar to results found previously by...
9901092v1
1999-03-10
Large Thermopower in a Layered Oxide NaCo_2O_4
A transition-metal oxide NaCo_2O_4 is a layered oxide in which CoO_2 and Na alternately stack along the c axis. Recently we have found that this compound shows unusually large thermopower with low resistivity, which is comparable to those of Bi_2Te_3. The negative transverse magnetoresistance and the strongly temperatu...
9903162v1
1999-07-05
Chiral Glass Phase in Ceramic Superconductors
A three-dimensional lattice of the Josephson junctions with a finite self-conductance is employed to model the ceramic superconductors. By Monte Carlo simulations it is shown that the chiral glass phase is stable in three dimensions even under the influence of screening. The nonlinear ac susceptibility and the compensa...
9907060v1
1999-09-01
Polyethylene under tensile load: strain energy storage and breaking of linear and knotted alkanes probed by first-principles molecular dynamics calculations
The mechanical resistance of a polyethylene strand subject to tension and the way its properties are affected by the presence of a knot is studied using first-principles molecular dynamics calculations. The distribution of strain energy for the knotted chains has a well-defined shape that is very different from the one...
9909013v1
1999-11-09
Heat capacity and transport studies of the ferromagnetic superconductor RuSr2GdCu2O8
Resistivity, thermoelectric power and heat capacity are investigated in the ferromagnetic superconductor RuSr2GdCu2O8 with and without Zn substitution. The thermodynamic signatures of the ordering of the Ru moments and the paramagnetic Gd moments as well as the onset of superconductivity are all clearly seen and quanti...
9911135v1
2000-02-14
Scanned Probe Microscopy of Electronic Transport in Carbon Nanotubes
We use electrostatic force microscopy and scanned gate microscopy to probe the conducting properties of carbon nanotubes at room temperature. Multi-walled carbon nanotubes are shown to be diffusive conductors, while metallic single-walled carbon nanotubes are ballistic conductors over micron lengths. Semiconducting sin...
0002209v1
2000-03-27
Current and power spectrum in a magnetic tunnel device with an atomic size spacer
Current and its noise in a ferromagnetic double tunnel barrier device with a small spacer particle were studied in the framework of the sequential tunneling approach. Analytical formulae were derived for electron tunneling through the spacer particle containing only a single energy level. It was shown that Coulomb inte...
0003418v1
2000-05-25
Magnetic-Field-Driven Superconductor-Insulator-Type Transition in Graphite
A magnetic-field-driven transition from metallic- to semiconducting-type behavior in the basal-plane resistance takes place in highly oriented pyrolytic graphite at a field $H_c \sim 1~$kOe applied along the hexagonal c-axis. The analysis of the data reveals a striking similarity between this transition and that measur...
0005439v1
2000-11-29
Giant Magnetoresistance at the Interface of Iron Thin Films
Ag/Fe/Ag and Cr/Fe/Cr trilayers with a single $25 nm$ thick ferromagnetic layer exhibit giant magnetoresistance (GMR) type behavior. The resistance decreases for parallel and transversal magnetic field alignements with a Langevin-type magnetic field dependence up to B=12 T. The phenomenon is explained by a granular int...
0011491v1
2001-01-22
Orbital Correlations in the Ferromagnetic Half-Metal $CrO_{2}
We deduce a model relevant for the description of the ferromagnetic half-metal Chromium dioxide ($CrO_{2}$), widely used in magnetic recording technology. The model describes the effect of dynamical, local orbital correlations arising from local quantum chemistry of the material. A finite temperature solution of the mo...
0101335v1
2001-03-06
Coherent description of electrical and thermal impurity-and-phonon limited transport in simple metals
The electrical resistivity, thermoelectric power and electronic thermal conductivity of simple (isotropic) metals are studied in a uniform way. Starting from results of a variational solution of the Boltzmann equation, a generalized Matthiessen rule is used in order to superpose the inelastic (or not) electron-phonon a...
0103138v1
2001-03-08
Localization corrections to the anomalous Hall effect in a ferromagnet
We calculate the localization corrections to the anomalous Hall conductivity related to the contribution of spin-orbit scattering into the current vertex (side-jump mechanism). We show that in contrast to the ordinary Hall effect, there exists a nonvanishing localization correction to the anomalous Hall resistivity. Th...
0103182v1
2001-03-23
Premartensitic Transition in Ni2+xMn1-xGa Heusler Alloys
The temperature dependencies of the resistivity and magnetization of a series of Ni2+XMn1-XGa (X = 0 - 0.09) alloys were investigated. Along with the anomalies associated with ferromagnetic and martensitic transitions, well-defined anomalies were observed at the temperature of premartensitic transformation. The premart...
0103483v1
2001-04-24
Electrical current distribution across a metal-insulator-metal structure during bistable switching
Combining scanning electron microscopy (SEM) and electron-beam-induced current (EBIC) imaging with transport measurements, it is shown that the current flowing across a two-terminal oxide-based capacitor-like structure is preferentially confined in areas localized at defects. As the thin-film device switches between tw...
0104452v1
2001-04-24
A simple one-dimensional model of heat conduction which obeys Fourier's law
We present the computer simulation results of a chain of hard point particles with alternating masses interacting on its extremes with two thermal baths at different temperatures. We found that the system obeys Fourier's law at the thermodynamic limit. This result is against the actual belief that one dimensional syste...
0104453v1
2001-06-29
Landau diamagnetism revisited
The problem of diamagnetism, solved by Landau, continues to pose fascinating issues which have relevance even today. These issues relate to inherent quantum nature of the problem, the role of boundary and dissipation, the meaning of thermodynamic limits, and above all, the quantum-classical crossover occasioned by envi...
0106646v1
2001-07-12
Theory of Angular Magnetoresistance in CPP spin valves
The resistance of CPP spin valve is a continuous function of the angle $\theta $ between the magnetizations of both ferromagnets. We use the cicuit theory for non-collinear magnetoelectronics to compute the angular magnetoresistance of CPP spin valves taking the spin accumulation in the ferromagnetic layers into accoun...
0107250v1
2001-07-27
Large magnetoresistance using hybrid spin filter devices
A magnetic "spin filter" tunnel barrier, sandwiched between a non-magnetic metal and a magnetic metal, is used to create a new magnetoresistive tunnel device, somewhat analogous to an optical polarizer-analyzer configuration. The resistance of these trilayer structures depends on the relative magnetization orientation ...
0107571v1
2001-08-17
Negative Magneto-Resistance Beyond Weak Localization in Three-Dimensional Billiards: Effect of Arnold Diffusion
We investigate a semiclassical conductance for ballistic open three-dimensional (3-d) billiards. For partially or completely broken-ergodic 3-d billiards such as SO(2) symmetric billiards, the dependence of the conductance on the Fermi wavenumber is dramatically changed by the lead orientation. Application of a symmetr...
0108276v1
2001-08-29
Anomalous Co-site substitution effects on the physical properties of the thermoelectric oxide NaCo2O4
We prepared polycrystalline samples of NaCo2-xMxO4 substituted for the Co site by other 3d or 4d elements (M=Mn,Cu, Zn, Ru, Rh, and Pd). While some of the elements (M=Mn,Ru and Rh) act as a strong scatterer to give rise to a rapid increase in resistivity, the others (M=Cu, Zn and Pd) do not deteriorate the electric con...
0108485v1
2001-10-05
Successive Phase Transitions in a Metal-Ordered Manganite Perovskite YBaMn2O6
Structural, magnetic and electric properties of a metal-ordered perovskite YBaMn2O6 have been studied by means of powder X-ray diffraction, DSC, magnetic susceptibility, and electric resistivity. It is found that this material undergoes a 1st order structural phase transition at Tc1=520 K, from a pseudo orthorhombic (m...
0110114v1
2002-04-29
Nonlinear charging, and transport times in doped nanotubes junctions
The nonlinear capacitance in doped nanotube junctions is calculated self consistently. It decreases as a function of the applied bias when the latter becomes larger than the pseudogap of the nanotube. For this device, one can deduce a relaxation time of about 0.1 femtosecond. Because of its negative differential resist...
0204609v3
2002-06-24
Boltzmann theory of engineered anisotropic magnetoresistance in (Ga,Mn)As
We report on a theoretical study of dc transport coefficients in (Ga,Mn)As diluted magnetic semiconductor ferromagnets that accounts for quasiparticle scattering from ionized Mn$^{2+}$ acceptors with a local moment $S=5/2$ and from non-magnetic compensating defects. In metallic samples Boltzmann transport theory with G...
0206416v1
2002-07-16
Carbon Nanotubes as Schottky Barrier Transistors
We show that carbon nanotube transistors operate as unconventional "Schottky barrier transistors", in which transistor action occurs primarily by varying the contact resistance rather than the channel conductance. Transistor characteristics are calculated for both idealized and realistic geometries, and scaling behavio...
0207397v1
2002-09-13
Some Thermal and Electrical Properties of Candelilla Wax
We report the values of some thermal and electrical properties of Candelilla Wax (euphorbia cerifera). The open-cell photoacoustic technique and another photothermic technique - based on the measure of the temperature decay of a heated sample - were employed to obtain the thermal diffusivity ($\alpha_{s} = 0.026 \pm 0....
0209328v1
2002-09-25
Magnetic properties of Ni2.18Mn0.82Ga Heusler alloys with a coupled magnetostructural transition
Polycrystalline Ni2.18Mn0.82Ga Heusler alloys with a coupled magnetostructural transition are studied by differential scanning calorimetry, magnetic and resistivity measurements. Coupling of the magnetic and structural subsystems results in unusual magnetic features of the alloy. These uncommon magnetic properties of N...
0209574v1
2002-10-04
The Effects of the Misfit Structure on Thermoelectric Properties of Bi2-xPbxSr2Co2Oy Single Crystals
In-plane anisotropy of the resistivity and thermopower was measured for single crystal Bi2-xPbxSr2Co2Oy. There is large in-plane anisotropy, which is attributed to the anisotropic pseudogap formation due to the different crystal symmetry between the square Bi2Sr2O4 layer and the triangular CuO2 layer. The magnitude of ...
0210087v1
2002-10-21
Competing SDW Phases and Quantum Oscillations in (TMTSF)2ClO4 in Magnetic Field
We propose a new approach for studying spin density waves (SDW) in the Bechgaard salt (TMTSF)2ClO4 where lattice is dimerized in transverse direction due to anion ordering. The SDW response is calculated in the matrix formulation that rigorously treats the hybridization of inter-band and intra-band SDW correlations. Si...
0210452v1
2002-10-28
Fine "mist" vs large droplets in phase separated manganites
The properties of phase-separated systems, e.g. manganites, close to a I order phase transition between charge-ordered insulator and ferromagnetic metal, are usually described by the percolation picture. We argue that the correlated occupation of metallic sites leads to the preferential formation of larger metallic clu...
0210616v1
2002-11-12
Infrared properties of W-doped charge-density-wave material K$_{0.3}$MoO$_3$
The optical conductivity spectra of quasi-one dimensional compounds K$_{0.3}$Mo$_{1-x}$W$_x$O$_3$ (x=0, 0.03 and 0.15) have been studied over broad frequencies. While the dc resistivity measurements indicate no sign of CDW transition in heavily W-doped blue bronze, the optical conductivity spectra still show a single p...
0211225v1
2002-11-18
Anomalous Hall Effect of Reentrant Spin Glass System Fe1-xAlx (x ~ 0.3)
The anomalous Hall coefficient Rs has been studied for the reentrant spin glass system Fe0.7Al0.3 by measuring the magnetization M and the Hall resistivity r_H. We have found that R_s exhibits anomalous temperature dependence at the spin-glass transition temperature T_G, indicating that an additional term appears along...
0211368v1
2002-12-01
The superconducting gap of \QTR{em}{in situ} $MgB_{2}$ thin films by microwave surface impedance measurements
Precision measurements of the microwave surface resistance $R_{s}$ of in situ $MgB_{2}$ films directly reveal an exponential behavior of $R_{s}$ at low temperature indicating a fully-gapped order parameter. The entire temperature dependence of $R_{s}$ is well described by a Mattis-Bardeen formalism but with a small gap...
0212009v1
2002-12-09
Conductance switching in a molecular device: the role of sidegroups and intermolecular interactio
We report first-principles studies of electronic transport in monolayers of Tour wires functionalized with different side groups. An analysis of the scattering states and transmission eigenchannels suggests that the functionalization does not strongly affect the resonances responsible for current flow through the monol...
0212191v1
2003-04-24
The spin-torque transistor
A magnetoelectronic thin-film transistor is proposed that can display negative differential resistance and gain. The working principle is the modulation of the soure-drain current in a spin valve by the magnetization of a third electrode, which is rotated by the spin-torque created by a control spin-valve. The device c...
0304550v1
2003-05-27
Double Magnetic Transition in Pr0.5Sr0.5CoO3
We report studies of polycrystalline samples of the metallic ferromagnet Pr0.5Sr0.5CoO3 through measurements of the magnetization, a.c. magnetic susceptibility, resistivity, and specific heat. We find an unusual anomaly around TA = 120 K, much below the ferromagnetic transition (TC = 226 K). The anomaly is manifested i...
0305621v1
2003-06-08
Analysis Of Critical Power Loss In A Superconductor
A critical power dissipation resulting from an oscillating magnetic field, Hp cos wt, can produce a magnetic breakdown field, H <Hc, the critical field of the superconductor. The analysis shows, for example, why the breakdown field of a superconducting microwave cavity can be well below Hc in some cases, and indicates ...
0306202v1
2003-07-11
Enhanced thermoelectric properties of NaxCoO2 whisker crystals
Single-crystalline whiskers of thermoelectric cobalt oxide, NaxCoO2, have been grown by an unconventional method from potassium-containing compositions, and their transport properties, and chemical compositions were determined. The growth mechanism was analyzed and interpreted by means of thermogravimetric analysis. At...
0307277v1
2003-07-31
Reflection of electrons from a domain wall in magnetic nanojunctions
Electronic transport through thin and laterally constrained domain walls in ferromagnetic nanojunctions is analyzed theoretically. The description is formulated in the basis of scattering states. The resistance of the domain wall is calculated in the regime of strong electron reflection from the wall. It is shown that ...
0307765v1
2003-08-16
Frequency Dependence of Superconducting Cavity Q and Magnetic Breakdown Field
A theoretical explanation is given to account for the unexpected observation that L- and S-band Nb superconducting cavities were found to have lower Q and lower magnetic breakdown field than those of the higher X-band frequencies. Both effects can be related to the trapping of magnetic flux in the cavity walls. The fre...
0308324v1
2003-08-22
Relevance of Cooperative Lattice Effects and Correlated Disorder in Phase-Separation Theories for CMR Manganites
Previous theoretical investigations of colossal magnetoresistance (CMR) materials explain this effect using a ``clustered'' state with preformed ferromagnetic islands that rapidly align their moments with increasing external magnetic fields. While qualitatively successful, explicit calculations indicate drastically dif...
0308456v1
2003-09-13
Metal-insulator transition in Ca_{1-x}Li_xPd_3O_4
Metal-insulator transition in Ca_{1-x}Li_xPd_3O_4 has been studied through charge transport measurements. The resistivity, the Seebeck coefficient, and the Hall coefficient are consistently explained in terms of a simple one-band picture, where a hole with a moderately enhanced mass is itinerant three-dimensionally. Co...
0309335v1
2003-10-10
Charge transport in l-DNA probed by conducting-AFM, and relationship with its structure
We studied the electrical conductivity of DNA samples as function of the number of DNA molecules. We showed that the insulating gap (no current at low voltage) increases from ~1-2 V for bundles and large ropes to ~4-7 V for few DNA molecules. From the distance dependent variation of the current, a unique hopping distan...
0310242v1
2003-12-18
Spin momentum transfer in current perpendicular to the plane spin valves
We present experimental and numerical micromagnetic data on the effect of spin momentum transfer in current perpendicular to the plane spin valves. Starting from a configuration with orthogonal free and pinned layer magnetizations, the free layer magnetization exhibits abrupt current induced switching that is qualitati...
0312505v1
2004-03-24
New Pyrochlore Oxide Superconductor RbOs2O6
We report the discovery of a new pyrochlore oxide superconductor RbOs2O6. The compound crystallizes in the same beta-pyrochlore structure as the recently discovered superconductor KOs2O6, where Os atoms form a corner-sharing tetrahedral network called the pyrochlore lattice with Rb or K atoms in the cage. Resistivity, ...
0403601v2
2004-04-16
Quenched growth of nanostructured lead thin films on insulating substrates
Lead island films were obtained via vacuum vapor deposition on glass and ceramic substrates at 80 K. Electrical conductance was measured during vapor condensation and further annealing of the film up to room temperature. The resistance behavior during film formation and atomic force microscopy of annealed films were us...
0404393v2
2004-04-28
Current-induced magnetization reversal in a (Ga,Mn)As-based magnetic tunnel junction
We report current-induced magnetization reversal in a ferromagnetic semiconductor-based magnetic tunnel junction (Ga,Mn)As/AlAs/(Ga,Mn)As prepared by molecular beam epitaxy on a p-GaAs(001) substrate. A change in magneto-resistance that is asymmetric with respect to the current direction is found with the excitation cu...
0404663v1
2004-04-30
Spin-dependent transport in molecular tunnel junctions
We present measurements of magnetic tunnel junctions made using a self-assembled-monolayer molecular barrier. Ni/octanethiol/Ni samples were fabricated in a nanopore geometry. The devices exhibit significant changes in resistance as the angle between the magnetic moments in the two electrodes is varied, demonstrating t...
0404740v1
2004-08-07
Hystersis like behaviour in Thin Films with heating-cooling cycle
The expression of temperature distribution along a film thickness is derived and distribution of temperature in the film as the substrate is heated is shown. The variation of film resistance with different substrate temperature is calculated and the existence of temperature gradient along the film thickness with finite...
0408163v1
2004-10-12
Quasi-ballistic electron transport in double-wall carbon nanotubes
Room-temperature quasi-ballistic electron transport in double-wall carbon nanotubes (DWNT) is demonstrated. Conductance dependence on the length was measured by submerging DWNTs into liquid mercury. The conductance plots show plateaus, indicating weak dependence of the electrode-tube-electrode electrical resistance on ...
0410310v1
2004-11-07
Sub 20 nm Short Channel Carbon Nanotube Transistors
Carbon nanotube field-effect transistors with sub 20 nm long channels and on/off current ratios of > 1000000 are demonstrated. Individual single-walled carbon nanotubes with diameters ranging from 0.7 nm to 1.1 nm grown from structured catalytic islands using chemical vapor deposition at 700 degree Celsius form the cha...
0411177v1
2004-11-11
Ferromagnetic-superconducting hybrid films and their possible applications: A direct study in a model combinatorial film
Model combinatorial films (CFs) which host a pure superconductor adjacent to a ferromagneticsuperconducting hybrid film (HF) are manufactured for the study of the influence of ferromagnetic nanoparticles (FNs) on the nucleation of superconductivity. Careful resistance measurements were performed simultaneously on two d...
0411311v1
2004-12-20
Carbon Nanotubes for Interconnect Applications
We briefly review the status of the application of carbon nanotubes (CNTs) for future interconnects and present results concerning possible integration schemes. Growth of single nanotubes at lithographically defined locations (vias) has been achieved which is a prerequisite for the use of CNTs as future interconnects. ...
0412537v1
2005-01-12
Nanoengineered Curie Temperature in Laterally-Patterned Ferromagnetic Semiconductor Heterostructures
We demonstrate the manipulation of the Curie temperature of buried layers of the ferromagnetic semiconductor (Ga,Mn)As using nanolithography to enhance the effect of annealing. Patterning the GaAs-capped ferromagnetic layers into nanowires exposes free surfaces at the sidewalls of the patterned (Ga,Mn)As layers and thu...
0501298v2
2005-01-29
Spin accumulation and decay in magnetic Schottky barriers
The theory of charge and spin transport in forward-biased Schottky barriers reveals characteristic and experimentally relevant features. The conductance mismatch is found to enhance the current induced spin-imbalance in the semiconductor. The GaAs|MnAs interface resistance is obtained from an analysis of the magnetic f...
0501726v1
2005-02-01
Adsorption of Oxygen Molecules on Individual Carbon Single-walled Nanotubes
Our study of the adsorption of oxygen molecules on individual semiconductiong single-walled carbon nanotubes at ambient conditions reveals that the adsorption is physisorption, that the resistance without O2 increases by ~two orders of magnitude as compared to that with O2, and that the sensitive response is due to the...
0502012v1
2005-03-07
Physical properties, strontium ordering and structural modulation in layered hexagonal Sr0.35CoO2
Layered Sr0.35CoO2 has been synthesized by means of an ion exchange reaction from Na0.7CoO2. Resistivity measurements show that this material can be either metallic or semiconducting depending on the annealing conditions. Magnetic susceptibility, following the Curie-Weiss law, increases with lowering temperature and sh...
0503136v1
2005-04-12
Polaron Transport in the Paramagnetic Phase of Electron-Doped Manganites
The electrical resistivity, Hall coefficient, and thermopower as functions of temperature are reported for lightly electron-doped Ca(1-x)La(x)MnO(3)(0 <= x <= 0.10). Unlike the case of hole-doped ferromagnetic manganites, the magnitude and temperature dependence of the Hall mobility for these compounds is found to be i...
0504303v1
2005-04-26
Spin filtering through ferromagnetic BiMnO3 tunnel barriers
We report on experiments of spin filtering through ultra-thin single-crystal layers of the insulating and ferromagnetic oxide BiMnO3 (BMO). The spin polarization of the electrons tunneling from a gold electrode through BMO is analyzed with a counter-electrode of the half-metallic oxide La2/3Sr1/3MnO3 (LSMO). At 3 K we ...
0504667v1
2005-05-16
Electronic mean free path in as-produced and purified single-wall carbon nanotubes
The effect of purification on room temperature electronic transport properties of single-wall carbon nanotubes (SWNT) was studied by submerging samples into liquid mercury. The conductance plots of purified SWNTs showed plateaus, indicating weak dependence of the electrical resistance on the length of the tube connecti...
0505377v1
2005-06-03
Magnetic and Transport Properties of Fe-Ag granular multilayers
Results of magnetization, magnetotransport and Mossbauer spectroscopy measurements of sequentially evaporated Fe-Ag granular composites are presented. The strong magnetic scattering of the conduction electrons is reflected in the sublinear temperature dependence of the resistance and in the large negative magnetoresist...
0506072v2
2005-07-06
A single molecule switch based on two Pd nanocrystals linked by a conjugated dithiol
Tunneling spectroscopy measurements have been carried out on a single molecule device formed by two Pd nanocrystals (dia, $\sim$5 nm) electronically coupled by a conducting molecule, dimercaptodiphenylacetylene. The I-V data, obtained by positioning the tip over a nanocrystal electrode, exhibit negative differential re...
0507147v1
2005-07-15
Spin transference and magnetoresistance amplification in a transistor
A current problem in semiconductor spin-based electronics is the difficulty of experimentally expressing the effect of spin-polarized current in electrical circuit measurements. We present a theoretical solution with the principle of transference of the spin diffusion effects in the semiconductor channel of a system wi...
0507378v2
2005-09-27
Electron-Hole Asymmetry in GdBaCo_{2}O_{5+x}: Evidence for Spin Blockade of Electron Transport in a Correlated Electron System
In RBaCo_{2}O_{5+x} compounds (R is rare earth) variability of the oxygen content allows precise doping of CoO_2 planes with both types of charge carriers. We study transport properties of doped GdBaCo_{2}O_{5+x} single crystals and find a remarkable asymmetry in the behavior of holes and electrons doped into a parent ...
0509673v1
2005-10-13
The electrical current effect in phase separated La5/8-yPryCa3/8MnO3: Charge order melting vs. Joule heating
We have studied the effect of electric field on transport properties of the prototypical phase separated manganite La5/8-yPryCa3/8MnO3 with y=0.34. Our results show that the suggested image in which the charge ordered state is melted by the appliance of an electric current and/or voltage has to be revised. We were able...
0510366v1
2005-12-16
A possible minimum toy model with negative differential capacitance for self-sustained current oscillation
We generalize a simple model for superlattices to include the effect of differential capacitance. It is shown that the model always has a stable steady-state solution (SSS) if all differential capacitances are positive. On the other hand, when negative differential capacitance is included, the model can have no stable ...
0512370v2
2006-01-13
Gamma radiation exposure of MCT diode arrays
Investigations of electrical properties of long-wavelength infrared (LWIR) mercury cadmium telluride (MCT) arrays exposed to gamma-radiation have been performed. Resistance-area product characteristics of LWIR n{+}-p photodiodes have been investigated using microprobe technique at T=78 K before and after an exposure to...
0601276v1
2006-01-13
Influence of Roughness and Disorder on Tunneling Magnetoresistance
A systematic, quantitative study of the effect of interface roughness and disorder on the magnetoresistance of FeCo$|$vacuum$|$FeCo magnetic tunnel junctions is presented based upon parameter-free electronic structure calculations. Surface roughness is found to have a very strong effect on the spin-polarized transport ...
0601291v2
2006-02-09
Strong Pinning Enhancement in MgB2 Using Very Small Dy2O3 Additions
0.5 to 5.0 wt.% Dy2O3 was in-situ reacted with Mg + B to form pinned MgB2. While Tc remained largely unchanged, Jc was strongly enhanced. The best sample (only 0.5 wt.% Dy2O3) had a Jc of 6.5 x 10^5 A/cm^2 at 6K, 1T and 3.5 x 10^5 A/cm^2 at 20K, 1T, around a factor of 4 higher compared to the pure sample, and equivalen...
0602234v1
2006-02-27
Origin of the large thermoelectric power in oxygen-variable RBaCo_{2}O_{5+x} (R=Gd, Nd)
Thermoelectric properties of GdBaCo_{2}O_{5+x} and NdBaCo_{2}O_{5+x} single crystals have been studied upon continuous doping of CoO_2 planes with either electrons or holes. The thermoelectric response and the resistivity behavior reveal a hopping character of the transport in both compounds, providing the basis for un...
0602618v1
2006-03-27
Modeling transient absorption and thermal conductivity in a simple nanofluid
Molecular dynamics simulations are used to simulate the thermal properties of a model fluid containing nanoparticles (nanofluid). By modelling transient absorption experiments, we show that they provide a reliable determination of interfacial resistance between the particle and the fluid. The flexibility of molecular s...
0603704v1
2006-05-04
Optical conductivity of charge carriers interacting with a two-level systems reservoir
Using the functional-integral method we investigate the effective dynamics of a charged particle coupled to a set of two-level systems as a function of temperature and external electric field. The optical conductivity and the direct current (dc) resistivity induced by the reservoir are computed. Three different regimes...
0605105v1
2006-05-24
Controlling charge injection in organic field-effect transistors using self-assembled monolayers
We have studied charge injection across the metal/organic semiconductor interface in bottom-contact poly(3-hexylthiophene) (P3HT) field-effect transistors, with Au source and drain electrodes modified by self-assembled monolayers (SAMs) prior to active polymer deposition. By using the SAM to engineer the effective Au w...
0605605v1
2006-08-10
Gate-controlled nuclear magnetic resonance in an AlGaAs/GaAs quantum Hall device
We study the resistively detected nuclear magnetic resonance (NMR) in an AlGaAs/GaAs quantum Hall device with a side gate. The strength of the hyperfine interaction between electron and nuclear spins is modulated by tuning a position of the two-dimensional electron systems with respect to the polarized nuclear spins us...
0608237v1
2006-08-27
Magnetic Switching of Phase-Slip Dissipation in NbSe2 Nanobelts
The stability of the superconducting dissipationless and resistive states in single-crystalline NbSe2 nanobelts is characterized by transport measurements in an external magnetic field (H). Current-driven electrical measurements show voltage steps, indicating the nucleation of phase-slip structures. Well below the crit...
0608586v1
2006-08-28
Inverse Spin Hall Effect by Spin Injection
Motivated by a recent experiment[Nature {\bf 442}, 176 (2006)], we present a quantitative microscopic theory to investigate the inverse spin-Hall effect with spin injection into aluminum considering both intrinsic and extrinsic spin-orbit couplings using the orthogonalized-plane-wave method. Our theoretical results are...
0608594v2
2006-08-31
Atomic and electronic structure of ultra-thin Al/AlOx/Al interfaces
Interfaces between metals based on AlO$_{x}$ represent the most popular basis for Josephson junctions or, more recently, also for junctions exhibiting substantial tunneling magneto-resistance. We have performed a computational study of possible local geometric structures of such interfaces at the ab-initio DFT/GGA leve...
0608718v1
2006-09-01
Nonlinear screening of charge impurities in graphene
It is shown that a ``vacuum polarization'' induced by Coulomb potential in graphene leads to a strong suppression of electric charges even for undoped case (no charge carriers). A standard linear response theory is therefore not applicable to describe the screening of charge impurities in graphene. In particular, it ov...
0609026v3
2006-09-14
Strain induced pressure effect in pulsed laser deposited thin films of the strongly correlated oxide V2O3
V2O3 thin films about 10 nm thick were grown on Al2O3 (0001) by pulsed laser deposition. The XRD analysis is in agreement with R-3c space group. Some of them exhibit the metal / insulator transition characteristic of V2O3 bulk material and others samples exhibit a metallic behavior. For the latter, the XPS analysis ind...
0609342v1
2006-09-19
Adaptive Programming of Unconventional Nano-Architectures
Novel assembly processes for nanocircuits could present compelling alternatives to the detailed design and placement currently used for computers. The resulting architectures however may not be programmable by standard means. In this paper, nanocomputers with unconventional architectures are programmed using adaptive m...
0609489v1
2006-09-20
Spin Injection and Nonlocal Spin Transport in Magnetic Nanostructures
We theoretically study the nonlocal spin transport in a device consisting of a nonmagnetic metal (N) and ferromagnetic injector (F1) and detector (F2) electrodes connected to N. We solve the spin-dependent transport equations in a device with arbitrary interface resistance from a metallic-contact to tunneling regime, a...
0609508v1
2006-09-21
Resistive and rectifying effects of pulling gold atoms at thiol-gold nano-contacts
We investigate, by means of first-principles calculations, structural and transport properties of junctions made of symmetric dithiolated molecules placed between Au electrodes. As the electrodes are pulled apart, we find that it becomes energetically favorable that Au atoms migrate to positions between the electrode s...
0609558v1
2006-11-15
Tunneling anisotropic magnetoresistance and spin-orbit coupling in Fe/GaAs/Au tunnel junctions
We report the observation of tunneling anisotropic magnetoresistance effect (TAMR) in the epitaxial metal-semiconductor system Fe/GaAs/Au. The observed two-fold anisotropy of the resistance can be switched by reversing the bias voltage, suggesting that the effect originates from the interference of the spin-orbit coupl...
0611406v1