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2023-07-31
Ferroelectricity in tetragonal ZrO$_2$ thin films
We report on the crystal structure and ferroelectric properties of epitaxial ZrO$_2$ films ranging from 7 to 42 nm thickness grown on La$_{0.67}$Sr$_{0.33}$MnO$_3$-buffered (110)-oriented SrTiO$_3$ substrate. By employing X-ray diffraction, we confirm a tetragonal phase at all investigated thicknesses, with slight in-p...
2307.16492v1
2023-08-16
Automated Semiconductor Defect Inspection in Scanning Electron Microscope Images: a Systematic Review
A growing need exists for efficient and accurate methods for detecting defects in semiconductor materials and devices. These defects can have a detrimental impact on the efficiency of the manufacturing process, because they cause critical failures and wafer-yield limitations. As nodes and patterns get smaller, even hig...
2308.08376v2
2023-10-05
Spin-orbit torques and spin Hall magnetoresistance generated by twin-free and amorphous Bi0.9Sb0.1 topological insulator films
Topological insulators have attracted great interest as generators of spin-orbit torques (SOTs) in spintronic devices. Bi\textsubscript{1-x}Sb\textsubscript{x} is a prominent topological insulator that has a high charge-to-spin conversion efficiency. However, the origin and magnitude of the SOTs induced by current-inje...
2310.03487v1
2023-12-09
Extended Kohler's Rule of Magnetoresistance in TaCo$_2$Te$_2$
TaCo$_2$Te$_2$ is recently reported to be an air-stable, high mobility Van der Waals material with probable magnetic order. Here we investigate the scaling behavior of its magnetoresistance. We measured both the longitudinal ($\rho_{xx}$) and Hall ($\rho_{xy}$) magnetoresistivities of TaCo$_2$Te$_2$ crystals in magneti...
2312.05624v1
2023-12-16
Electronic phase transition, vibrational properties and structural stability of single and two polyyne chains under external electric field
Search for one dimensional (1D) van der Waals materials has become an urgent need to meet the demand as building blocks for high performance, miniaturized, lightweight device applications. Polyyne, a 1D atomic chain of carbon is the thinnest and strongest allotrope of carbon, showing promising applications in new gener...
2312.10335v1
2024-02-06
Observation of the double quantum spin Hall phase in moiré WSe2
Quantum spin Hall (QSH) insulators are a topologically protected phase of matter in two dimensions that can support non-dissipative spin transport. A hallmark of the phase is a pair of helical edge states surrounding an insulating bulk. A higher (even) number of helical edge state pairs is usually not possible in real ...
2402.04196v1
2024-02-13
Coarse-Graining in Space versus Time
Understanding the structure and dynamics of liquids is pivotal for the study of larger spatiotemporal processes, particularly for glass-forming materials at low temperatures. The so-called thermodynamic scaling relation, validated for many molecular systems through experiments, offers an efficient means to explore a va...
2402.08675v1
2024-02-27
Design principles of nonlinear optical materials for Terahertz lasers
We have investigated both inter-band and intra-band second order nonlinear optical conductivity based on the velocity correlation formalism and the spectral expansion technique. We propose a scenario in which the second order intra-band process is nonzero while the inter-band process is zero. This occurs for a band str...
2402.17126v1
2024-03-25
Multi-Objective Quality-Diversity for Crystal Structure Prediction
Crystal structures are indispensable across various domains, from batteries to solar cells, and extensive research has been dedicated to predicting their properties based on their atomic configurations. However, prevailing Crystal Structure Prediction methods focus on identifying the most stable solutions that lie at t...
2403.17164v1
2002-08-26
Magnetized Accretion-Ejection Structures: 2.5D MHD simulations of continuous Ideal Jet launching from resistive accretion disks
We present numerical magnetohydrodynamic (MHD) simulations of a magnetized accretion disk launching trans-Alfvenic jets. These simulations, performed in a 2.5 dimensional time-dependent polytropic resistive MHD framework, model a resistive accretion disk threaded by an initial vertical magnetic field. The resistivity i...
0208459v1
2006-02-17
Coupling losses and transverse resistivity of multifilament YBCO coated superconductors
We studied the magnetization losses of four different types of filamentary YBCO coated conductors. A 10 mm wide YBCO coated conductor was subdivided into 20 filaments by laser cutting. The separation of coupling loss from the total is possible because the energy loss per cycle in samples with electrically insulated fil...
0602422v1
2007-02-21
Electrical current-driven pinhole formation and insulator-metal transition in tunnel junctions
Current Induced Resistance Switching (CIS) was recently observed in thin tunnel junctions (TJs) with ferromagnetic (FM) electrodes and attributed to electromigration of metallic atoms in nanoconstrictions in the insulating barrier. The CIS effect is here studied in TJs with two thin (20 \AA) non-magnetic (NM) Ta electr...
0702501v2
2008-12-15
Nanomechanical detection of antibiotic-mucopeptide binding in a model for superbug drug resistance
The alarming growth of the antibiotic-resistant superbugs methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) is driving the development of new technologies to investigate antibiotics and their modes of action. We report the label-free detection of vancomycin binding to bacter...
0812.2728v1
2010-05-19
Resistance in Superconductors
In this pedagogical review, we discuss how electrical resistance can arise in superconductors. Starting with the idea of the superconducting order parameter as a condensate wave function, we introduce vortices as topological excitations with quantized phase winding, and we show how phase slips occur when vortices cross...
1005.3347v1
2013-06-28
Impact of sintering temperature on room temperature magneto-resistive and magneto-caloric properties of Pr2/3Sr1/3MnO3
Magneto-resistive and magneto-caloric properties of polycrystalline Pr2/3Sr1/3MnO3 have been studied as a function of sintering temperature (Ts) between 1260-1450{\deg}C. Reitveld refinement of their X-ray diffraction (XRD) patterns confirms their single phase crystalline structure with orthorhombic Pbnm space group. T...
1306.6792v2
2014-11-15
Shock-waves and commutation speed of memristors
Progress of silicon based technology is nearing its physical limit, as minimum feature size of components is reaching a mere 10 nm. The resistive switching behaviour of transition metal oxides and the associated memristor device is emerging as a competitive technology for next generation electronics. Significant progre...
1411.4198v3
2015-09-29
Extraordinary Hall resistance and unconventional magnetoresistance in Pt/LaCoO3 hybrids
We report an investigation of transverse Hall resistance and longitudinal resistance on Pt thin films sputtered on epitaxial LaCoO$_3$ (LCO) ferromagnetic insulator films. The LaCoO$_3$ films were deposited on several single crystalline substrates [LaAlO$_3$ (LAO), (La,Sr)(Al,Ta)O$_3$ (LSAT), and SrTiO$_3$ (STO)] with ...
1509.08691v1
2016-02-24
Contact resistances in trigate and FinFET devices in a Non-Equilibrium Green's Functions approach
We compute the contact resistances $R_{\rm c}$ in trigate and FinFET devices with widths and heights in the 4 to 24 nm range using a Non-Equilibrium Green's Functions approach. Electron-phonon, surface roughness and Coulomb scattering are taken into account. We show that $R_{\rm c}$ represents a significant part of the...
1602.07545v1
2017-10-26
Effect of air confinement on thermal contact resistance in nanoscale heat transfer
We report herein the pressure dependent thermal contact resistance (Rc) between Wollaston wire thermal probe and samples which is evaluated within the framework of an analytical model. This work presents heat transfer between the Wollaston wire thermal probe and samples at nanoscale for different air pressure ranging f...
1710.09501v1
2017-11-08
Surface impedance and optimum surface resistance of a superconductor with imperfect surface
We calculate a low-frequency surface impedance of a dirty, s-wave superconductor with an imperfect surface incorporating either a thin layer with a reduced pairing constant or a thin, proximity-coupled normal layer. Such structures model realistic surfaces of superconducting materials which can contain oxide layers, ab...
1711.03077v1
2018-02-15
Parallel magnetic field suppresses dissipation in superconducting nanostrips
The motion of Abrikosov vortices in type-II superconductors results in a finite resistance in the presence of an applied electric current. Elimination or reduction of the resistance via immobilization of vortices is the "holy grail" of superconductivity research. Common wisdom dictates that an increase in the magnetic ...
1802.05673v1
2018-05-22
Structural properties and anisotropic electronic transport in SrIrO3 films
Perovskite SrIrO3 (SIO) films epitaxially deposited with a thickness of about 60 nm on various substrate materials display nearly strain-relieved state. Films grown on orthorhombic (110) DyScO3 (DSO) are found to display untwinned bulk-like orthorhombic structure. However, film deposition on cubic (001) SrTiO3 induces ...
1805.08473v2
2022-02-24
Thermal spreading resistance of GaN HEMTs with heat source heating studied by hybrid Monte Carlo-diffusion simulations
Exact assessment of thermal spreading resistance is of great importance to the thermal management of electronic devices, especially when completely considering the heat conduction process from the nanoscale heat source to the macroscopic scale heat sink. The existing simulation methods are either based on convectional ...
2202.13770v1
2007-10-10
Strong Reduction of the Field-Dependent Microwave Surface Resistance in YBCO with BaZrO_3 Inclusions
We present measurements of the magnetic field dependent microwave surface resistance in laser-ablated YBa$_2$Cu$_3$O$_{7-\delta}$ films on SrTiO$_3$ substrates. BaZrO$_3$ crystallites were included in the films using composite targets containing BaZrO$_3$ inclusions with mean grain size smaller than 1 $\mu$m. X-ray dif...
0710.1953v1
2018-07-19
Theoretical study of scattering in graphene ribbons in the presence of structural and atomistic edge roughness
We investigate the diffusive electron-transport properties of charge-doped graphene ribbons and nanoribbons with imperfect edges. We consider different regimes of edge scattering, ranging from wide graphene ribbons with (partially) diffusive edge scattering to ribbons with large width variations and nanoribbons with at...
1807.07263v2
2020-10-07
Correlation of uniaxial magnetic anisotropy axes and principal resistivities in polycrystalline ferromagnetic films
In the present study, we demonstrate the measurement of resistivity tensor ($\rho$) along the magnetic axes of a polycrystalline film of ferromagnetic permalloy (Py). To this end, conventional Hall-bar and a more recent extended van der Pauw methods were utilized for determining 2D $\rho$ in the film plane. The samples...
2010.03554v3
2020-12-31
DC Resistance Degradation of SrTiO$_3$: The Role of Virtual-Cathode Needles and Oxygen Bubbles
This study of highly accelerated lifetime tests of SrTiO$_3$, a model semiconducting oxide, is motivated by the interest in reliable multilayer ceramic capacitors and resistance-switching thin-film devices. Our analytical solution to oxygen-vacancy migration under a DC voltage -- the cause of resistance degradation in ...
2012.15777v1
2021-04-12
Temperature-linear Resistivity in Twisted Double Bilayer Graphene
We report an experimental study of carrier density (n), displacement field (D) and twist angle ({\theta}) dependence of temperature (T)-linear resistivity in twisted double bilayer graphene (TDBG). For a large twist angle ({\theta}>1.5{\deg}) where correlated insulating states are absent, we observe a T-linear resistiv...
2104.05406v3
2022-01-06
Coulomb drag in metal monochalcogenides double-layer structures with Mexican-hat band dispersions
We theoretically study the Coulomb drag resistivity and plasmon modes behavior for a system composed of two parallel p-type doped GaS monolayers with Mexican-hat valence energy band using the Boltzmann transport theory formalism. We investigate the effect of temperature,$\ T$, carrier density,$\ p$, and layer separatio...
2201.02077v1
2023-02-14
Acoustic phonon contribution to the resistivity of twisted bilayer graphene
We calculate the contribution to the doping ($n$) and temperature ($T$) dependence of the electrical resistivity of twisted bilayer graphene (TBLG) due to scattering by acoustic phonons. Our calculation retains the full Bistritzer-MacDonald (BM) band structure, with a focus on understanding the role of the complicated ...
2302.07275v3
2023-04-21
Star-Mesh Quantized Hall Array Resistance Devices
Advances in the development of graphene-based technology have enabled improvements in DC resistance metrology. Devices made from epitaxially grown graphene have replaced the GaAs-based counterparts, leading to an easier and more accessible realization of the ohm. By optimizing the scale of the growth, it has become pos...
2304.11243v1
2023-06-12
Symmetric, off-diagonal, resistance from rotational symmetry breaking in graphene-WSe$_2$ heterostructure: prediction for a large magic angle in a Moire system
We show that any two-dimensional system with a non-zero \textit{symmetric} off-diagonal component of the resistance matrix, $R_{xy}=R_{yx} \neq 0$, must have the in-plane rotational symmetry broken down to $C_2$. Such a resistance response is Ohmic, and is different from the Hall response which is the \textit{anti-symm...
2306.06840v2
2024-03-04
Electric field induced resistive switching in M$^{3+}_x$V$_{1-x}$O$_2$ (M$^{3+}$= Ga$^{3+}$, Al$^{3+}$) single crystals at temperatures below the T $\to$ M2 phase transition
The phase diagram of VO$_2$ strained or doped with several trivalent ions consists of four phases; in order of increasing temperatures, three (M1, T and M2) are insulating while the fourth (R), above ~340 K, is metallic. These phases and the three phase transitions have been thoroughly investigated for about half a cen...
2403.01808v2
2017-07-27
Experimental study of electron and phonon dynamics in nanoscale materials by ultrafast laser time-domain spectroscopy
With the rapid advances in the development of nanotechnology, nowadays, the sizes of elementary unit, i.e. transistor, of micro- and nanoelectronic devices are well deep into nanoscale. For the pursuit of cheaper and faster nanoscale electronic devices, the size of transistors keeps scaling down. As the miniaturization...
1707.08698v2
2002-10-17
New heat treatment to prepare high quality polycrystalline and single crystal MgB2 in single process
We report here on a new heat treatment to prepare both dense polycrystalline and single crystal MgB2 high quality samples in one single process. Resistivity measurements for polycrystalline part of the sample gives a residual resistivity ratio RRR=16.6 and a very low normal state resistivity rho(40K)= 0.28 microOhmcm. ...
0210384v1
2010-05-03
Overview of the DHCAL Project
We review the status and plans of the Digital Hadron Calorimeter with Resistive Plate Chambers project.
1005.0412v1
2010-08-26
Simulation of Edge Localised Modes using BOUT++
The BOUT++ code is used to simulate ELMs in a shifted circle equilibrium. Reduced ideal MHD simulations are first benchmarked against the linear ideal MHD code ELITE, showing good agreement. Diamagnetic drift effects are included finding the expected suppression of high toroidal mode number modes. Nonlinear simulations...
1008.4554v1
2021-05-24
Ageing studies of Multi-Strip Multi-Gap Resistive Plate Counters based on low resistivity glass electrodes in high irradiation dose
Detailed tests and analysis of ageing effects of high irradiation dose on Multi-Strip Multi-Gap Resistive Plate Counters based on low resistivity glass electrodes were performed. MSMGRPC efficiency and cluster size before irradiation are measured and compared with their values after irradiation in a high irradiation do...
2105.12214v2
2021-11-23
Superconducting aluminum heat switch with 3 n$Ω$ equivalent resistance
Superconducting heat switches with extremely low normal state resistances are needed for constructing continuous nuclear demagnetization refrigerators with high cooling power. Aluminum is a suitable superconductor for the heat switch because of its high Debye temperature and its commercial availability in high purity. ...
2111.11896v2
2023-02-18
Search for universal minimum drag resistance underwater vehicle hull using CFD
In Autonomous Underwater Vehicles (AUVs) design, hull resistance is an important factor in determining the power requirements and range of vehicle and consequently affect battery size, weight, and volume requirement of the design. In this paper, we leverage on AI-based optimization algorithm along with Computational Fl...
2302.09441v2
2019-11-22
Radiation Damage Studies on Titanium Alloys as High Intensity Proton Accelerator Beam Window Materials
A high-strength dual alpha+beta phase titanium alloy Ti-6Al-4V is utilized as a material for beam windows in several accelerator target facilities. However, relatively little is known about how material properties of this alloy are affected by high-intensity proton beam irradiation. With plans to upgrade neutrino facil...
1911.10198v1
2023-09-26
The $p_0$-Laplace "Signature" for Quasilinear Inverse Problems
This paper refers to an imaging problem in the presence of nonlinear materials. Specifically, the problem we address falls within the framework of Electrical Resistance Tomography and involves two different materials, one or both of which are nonlinear. Tomography with nonlinear materials in the early stages of develop...
2309.15865v2
1996-11-30
Exchange coupling and current-perpendicular-to-plane giant magneto-resistance of magnetic trilayers. Rigorous results within a tight-binding single-band model
It is shown that the current-perpendicular-to-plane giant magneto-resistance (CPP-GMR) oscillations, in the ballistic regime, are strongly correlated with those of the exchange coupling (J). Both the GMR and J are treated on equal footing within a rigorously solvable tight-binding single-band model. The strong correlat...
9612008v1
1998-09-30
Thickness dependent magnetotransport in ultra-thin manganite films
To understand the near-interface magnetism in manganites, uniform, ultra-thin films of La_{0.67}Sr_{0.33}MnO_3 were grown epitaxially on single crystal (001) LaAlO_3 and (110) NdGaO_3 substrates. The temperature and magnetic field dependent film resistance is used to probe the film's structural and magnetic properties....
9809414v1
1999-10-14
Giant 1/f noise in perovskite manganites: evidence of the percolation threshold
We discovered an unprecedented magnitude of the 1/f noise near the Curie temperature Tc in low-Tc manganites. The scaling behavior of the 1/f noise and the resistance provides strong evidence of the percolation nature of the ferromagnetic transition in the polycrystalline samples. The step-like changes of the resistanc...
9910220v1
2000-01-12
Anomalous Hopping Exponents of Ultrathin Films of Metals
The temperature dependence of the resistance R(T) of ultrathin quench-condensed films of Ag, Bi, Pb and Pd has been investigated. In the most resistive films, R(T)=Roexp(To/T)^x, where x=0.75. Surprisingly, the exponent x was found to be constant for a wide range of Ro and To in all four materials, possibly implying a ...
0001162v1
2000-07-03
The mean free path for electron conduction in metallic fullerenes
We calculate the electrical resistivity due to electron-phonon scattering for a model of A3C60 (A= K, Rb), using an essentially exact quantum Monte-Carlo calculation. In agreement with experiment, we obtain exceptionally large metallic resistivities at large temperatures T. This illustrates that the apparent mean free ...
0007024v1
2000-09-04
Observation of anomalous single-magnon scattering in half-metallic ferromagnets by chemical pressure control
Temperature variation of resistivity and specific heat have been measured for prototypical half-metallic ferromagnets, R_0.6Sr_0.4MnO_3, with controlling the one-electron bandwidth W. We have found variation of the temperature scalings in the resistivity from T^2 (R = La, and Nd) to T^3 (R = Sm), and have interpret...
0009035v1
2000-10-25
Ca0.85Sm0.15MnO3: A mixed antiferromagnet with unusual properties
We investigated electrical and magnetic properties of the electron-doped manganites Ca1-xSmxMnO3 (0<x<0.2). Our results indicate the possibility of phase separation in electron doped manganites. The compounds with x = 0.13-0.15 show unusual difference between zero-field cooled and field-cooled resistivities which are n...
0010384v1
2001-08-21
Metals with Small Electron Mean-Free Path: Saturation versus Escalation of Resistivity
Resistivity of metals is commonly observed either to 'escalate' beyond the Ioffe-Regel limit (mean free path l equal to lattice constant a) or to 'saturate' at this point. It is argued that neither behavior is well-understood, and that 'escalation' is not necessarily more mysterious than 'saturation.'
0108343v2
2002-02-18
Conductivity Oscillations in Current-Induced Metastable States in Low-Doped Manganite Single Crystals
Deterministic oscillations of current-induced metastable resistivity in changing voltage have been detected in La$_{0.82}$Ca$_{0.18}$MnO$_3$ single crystals. At low temperatures, below the Curie point, application of specific bias procedures switches the crystal into metastable resistivity state characterized by appear...
0202284v1
2002-02-20
Universal transport in 2D granular superconductors
The transport properties of quench condensed granular superconductors are presented and analyzed. These systems exhibit transitions from insulating to superconducting behavior as a function of inter-grain spacing. Superconductivity is characterized by broad transitions in which the resistance drops exponentially with r...
0202342v1
2002-05-22
Universal angular magnetoresistance and spin torque in ferromagnetic/normal metal hybrids
The electrical resistance of ferromagnetic/normal-metal (F/N) heterostructures depends on the nature of the junctions which may be tunnel barriers, point contacts, or intermetallic interfaces. For all junction types, the resistance of disordered F/N/F perpendicular spin valves as a function of the angle between magneti...
0205453v1
2002-08-22
A scheme for electrical detection of spin resonance signal from a single electron trap
We study a scheme for electrical detection of the spin resonance (ESR) of a single electron trapped near a Field Effect Transistor (FET) conduction channel. In this scheme, the resonant Rabi oscillations of the trapped electron spin cause a modification of the average occupancy of a shallow trap, which can be detected ...
0208438v1
2003-02-20
Electron scattering near an itinerant to localized electronic transition
We report an unconventional temperature dependence of the resistivity in several strongly correlated systems approaching a localized to itinerant electronic transition from the itinerant electron side. The observed resistivity, proportioanl to T^(3/2)over the entire range of materials discussed, cannot be explained wit...
0302426v1
2003-03-10
New collective zero-resistance states in GaAs/AlGaAs heterostructures
Exponentially small resistance in crossed static magnetic and microwave fields occurs in ultrapure two dimensional electron gases (2DEG), while in less pure systems the magnetoresistance oscillates but is always positive. A non-perturbative theory of self-organization explains the new collective states in terms of open...
0303181v1
2003-04-04
Co-ordination between Rashba spin-orbital interaction and space charge effect and enhanced spin injection into semiconductors
We consider the effect of the Rashba spin-orbital interaction and space charge in a ferromagnet-insulator/semiconductor/insulator-ferromagnet junction where the spin current is severely affected by the doping, band structure and charge screening in the semiconductor. In diffusion region, if the the resistance of the tu...
0304117v1
2003-07-17
Electron interaction with domain walls in antiferromagnetically coupled multilayers
For antiferromagnetically coupled Fe/Cr multilayers the low field contribution to the resistivity, which is caused by the domain walls, is strongly enhanced at low temperatures. The low temperature resistivity varies according to a power law with the exponent about 0.7 to 1. This behavior can not be explained assuming ...
0307414v1
2004-01-16
Break-Junction Tunneling Spectroscopy for Doped Semiconductors in the Hopping Regime
We present a theory for tunneling spectroscopy in a break-junction semiconductor device for materials in which the electronic conduction mechanism is hopping transport. Starting from the conventional expression for the hopping current we develop an expression for the break-junction tunnel current for the case in which ...
0401282v1
2004-02-05
Resistivity model for both paramagnetic and ferromagnetic phases
The resistivity, $\rho$ as a function of temperature and ionization energy (doping) and magnetization respectively is derived with further confinements from spin-disorder scattering. The computed $T_{crossover}$ below $T_C$ and carrier density in Ga$_{1-x}$Mn$_x$As system are 8-12 K and 10$^{19}$ cm$^{-3}$, remarkably ...
0402153v5
2004-05-26
The steady state in noncollinear magnetic multilayers
There are at least two different putative steady state solutions for current across noncollinear magnetic multilayers; one has a discontinuity in the spin current at the interface the other is continuous. We compare the resistance of the two and find the solution with the continuous spin currents is lower. By using the...
0405624v1
2004-06-09
Negative Magnetoresistance in (In,Mn)As
The magnetotransport properties of an In0.95Mn0.05As thin film grown by metal-organic vapor phase epitaxy were measured. Resistivity was measured over the temperature range of 5 to 300 K. The resistivity decreased with increasing temperature from 90 ohm-cm to 0.05 ohm-cm. The field dependence of the low temperature mag...
0406230v1
2004-06-21
Large negative magnetoresistance in thiospinel CuCrZrS4
We report on large negative magnetoresistance observed in ferromagnetic thiospinel compound CuCrZrS$_{4}$. Electrical resistivity increased with decreasing temperature according to the form proportional to $\textrm{exp}(T_{0}/T)^{1/2} $, derived from variable range hopping with strong electron-electron interaction. Res...
0406459v1
2004-08-27
Disorder-Induced Resistive Anomaly Near Ferromagnetic Phase Transitions
We show that the resistivity rho(T) of disordered ferromagnets near, and above, the Curie temperature T_c generically exhibits a stronger anomaly than the scaling-based Fisher-Langer prediction. Treating transport beyond the Boltzmann description, we find that within mean-field theory, d\rho/dT exhibits a |T-T_c|^{-1/2...
0408602v2
2004-10-07
Negative differential thermal resistance and thermal transistor
We report on the first model of a thermal transistor to control heat flow. Like its electronic counterpart, our thermal transistor is a three-terminal device with the important feature that the current through the two terminals can be controlled by small changes in the temperature or in the current through the third te...
0410172v2
2004-11-23
Current perpendicular to plane Giant Magnetoresistance (GMR) in laminated nanostructures
We theoretically studied spin dependent electron transport perpendicular-to-plain (CPP) in magnetic laminated multilayered structures by using Kubo formalism. We took into account not only bulk scattering, but the interface resistance due to both specular and diffuse reflection and also spin conserving and spin-flip pr...
0411571v1
2004-12-08
Ageing effects around the glass and melting transitions in poly(dimethylsiloxane) visualized by resistance measurements
The process of ageing in rubbers requires monitoring over long periods (days to years). To do so in non-conducting rubbers, small amounts of carbon-black particles were dispersed in a fractal network through the rubber matrix, to make the rubber conducting without modifying its properties. Continuous monitoring of the ...
0412187v1
2005-04-19
Enhancement of low field magnetoresistance at room temperature in La$_{0.67}$Sr$_{0.33}$MnO$_{3}$/Al$_{2}$O$_{3}$ nanocomposite
Magnetotransport properties in a nanocrystalline La$_{0.67}$Sr$_{0.33}$MnO$_{3}$/micron sized Al$_{2}$O$_{3}$ granular composite with different concentrations of Al$_{2}$O$_{3}$ have been studied. The resistivity curves in absence of magnetic field and the various transport mechanisms which might account for the upturn...
0504469v1
2005-09-09
Negative differential resistance in single crystal La_{2}CuO_{4} at low temperature
A current-controlled negative differential resistance has been revealed in the I-V characteristics of single crystal La$_{2}$CuO$_{4+\delta}$ in the low temperature region. The non-linear behavior of conductivity is accompanied by a transition from positive to negative magnetoresistance when the current is growing. Pos...
0509247v1
2005-11-02
Current-induced vortex displacement and annihilation in a single Permalloy disk
The induced motion of a magnetic vortex in a micron-sized ferromagnetic disk due to the DC current injection is studied by measuring planar Hall effect. The DC current injection is found to induce the spin torque that sweeps the vortex out of the disk at the critical current while bias magnetic field are applied. The c...
0511040v1
2006-01-20
Domain-wall resistance in ferromagnetic (Ga,Mn)As
A series of microstructures designed to pin domain-walls (DWs) in (Ga,Mn)As with perpendicular magnetic anisotropy has been employed to determine extrinsic and intrinsic contributions to DW resistance. The former is explained quantitatively as resulting from a polarity change in the Hall electric field at DW. The latte...
0601464v1
2006-01-25
Single-ion Kondo behavior of a novel Kondo lattice, CeNi9Si4
The compound, CeNi9Si4 has been recently reported to be an unusual Kondo lattice with a large Ce-Ce separation, with a breakdown of Kadowaki-Woods relationship governing low temperature electrical resistivity and heat-capacity. Here we report the results of magnetic susceptibility, heat-capacity and electrical resistiv...
0601577v1
2006-05-12
Large domain wall resistance in self-organised manganite film
The electrical resistance of magnetic domain walls in ferromagnetic metallic manganites can be enhanced to 10-12 Ohm.m2 by patterning nanoconstrictions [J. Appl. Phys. 89, 6955 (2001)]. We show equally large enhancements in a phase separated La0.60Ca0.40MnO3 manganite film without recourse to nanopatterning. The domain...
0605341v2
2006-06-18
Cotunneling and one-dimensional localization in individual single-wall carbon nanotubes
We report on the temperature dependence of the intrinsic resistance of long individual disordered single-wall carbon nanotubes. The resistance grows dramatically as the temperature is reduced, and the functional form is consistent with an activated behavior. These results are described by Coulomb blockade along a serie...
0606473v1
2006-10-10
Nanofabrication of spin-transfer torque devices by a PMMA mask one step process: GMR versus single layer devices
We present a method to prepare magnetic spin torque devices of low specific resistance in a one step lithography process. The quality of the pillar devices is demonstrated for a standard magnetic double layer device. For single layer devices, we found hysteretic switching and a more complex dynamical excitation pattern...
0610277v1
2006-11-27
Complete stabilization and improvement of the characteristics of tunnel junctions by thermal annealing
We have observed that submicron sized Al--AlO{$_x$}--Al tunnel junctions can be stabilized completely by annealing them in vacuum at temperatures between $350^{\circ}$C and $450^{\circ}$C. In addition, low temperature characterization of the samples after the annealing treatment showed a marked improvement of the tunne...
0611664v1
2007-01-17
Theory of Spin Transport Across Domain-Walls in (Ga,Mn)As
We present results of numerical calculations of domain-wall resistance in the ferromagnetic semiconductor (Ga,Mn)As. We employ Landauer-Buttiker formalism and the tight binding method. Taking into account the full valence band structure we predict the magnitude of the domain-wall resistance without disorder and compare...
0701398v1
2007-06-01
Treatment of electron viscosity in quantum conductance
In a recent paper Sai {\it et al.} [1] identified a correction $R^{dyn}$ to the DC conductance of nanoscale junctions arising from dynamical exchange-correlation ($XC$) effects within time-dependent density functional theory. This quantity contributes to the total resistance through $R=R_{s}+R^{dyn}$ where $R_{s}$ is t...
0706.0140v1
2007-07-05
Observation of a uniform temperature dependence in the electrical resistance across the structural phase transition in thin film vanadium oxide ($VO_{2}$)
An electrical study of thin $VO_{2}$ films in the vicinity of the structural phase transition at $68^{0}C$ shows (a) that the electrical resistance $R$ follows $log (R)$ $\propto$ $-T$ over the $T$-range, $20 < T < 80 ^{0}C$ covering both sides of the structural transition, and (b) a history dependent hysteresis loop i...
0707.0885v1
2007-08-07
Nonlinear screening and ballistic transport in a graphene p-n junction
We study the charge density distribution, the electric field profile, and the resistance of an electrostatically created lateral p-n junction in graphene. We show that the electric field at the interface of the electron and hole regions is strongly enhanced due to limited screening capacity of Dirac quasiparticles. Acc...
0708.0892v2
2007-08-22
Voltage and temperature dependencies of conductivity in gated graphene
The resistivity of gated graphene is studied taking into account electron and hole scattering by short- and long-range structural imperfections the characteristics of disorder were taken from the scanning tunneling microscopy data and by acoustic phonons. The calculations are based on the quasiclassical kinetic equatio...
0708.2976v2
2007-09-12
Design issues of a variable thermal resistance
Some years ago we have proposed a thermal mount with electronically variable thermal resistance [1]. In this earlier work the feasibility of such a structure has been demonstrated. Now we intend to realize this mount in a maturated form, suitable to the everyday use in the practice of package thermal qualification and ...
0709.1836v1
2007-11-29
Quantum size effects in solitary wires of bismuth
We have performed four-probe electrical transport measurements on solitary highly crystalline wires of semimetallic bismuth with aspect ratios up to 60 at room and at cryogenic temperatures. By proper choice of the substrate material and the film deposition parameters, lithographic wires with lateral dimensions of down...
0711.4816v1
2008-02-15
Non-intrinsic superconductivity in InN epilayers: role of Indium Oxide
In recent years there have been reports of anomalous electrical resistivity and the presence of superconductivity in semiconducting InN layers. By a careful correlation of the temperature dependence of resistivity and magnetic susceptibility with structural information from highresolution x-ray diffraction measurements...
0802.2126v1
2008-03-26
Quasi-Two-Dimensional Extraordinary Hall Effect
Quasi-two-dimensional transport is investigated in a system consisting of one ferromagnetic layer placed between two insulating layers. Using the mechanism of skew-scattering to describe the Extraordinary Hall Effect (EHE) and calculating the conductivity tensor, we compare the quasi- two-dimensional Hall resistance wi...
0803.3649v2
2008-04-17
Conductivity behavior of La$_{0.75}$Ca$_{0.25}$MnO$_{3}$ in vicinity of ferromagnetic-paramagnetic transition studied with single current pulses
Temperature and current dependences of resistivity of bulk La$_{0.75}$Ca$_{0.25}$MnO$_{3}$ sample grown by the floating-zone method were studied using single ramp pulses of current. It is found that near the Curie temperature $T_C$ the sample resistance depends substantially on current magnitude. The observed features ...
0804.2806v1
2008-05-13
Temperature dependent transport in suspended graphene
The resistivity of ultra-clean suspended graphene is strongly temperature dependent for 5K<T<240K. At T~5K transport is near-ballistic in a device of ~2um dimension and a mobility ~170,000 cm^2/Vs. At large carrier density, n>0.5*10^11 cm^-2, the resistivity increases with increasing T and is linear above 50K, suggesti...
0805.1830v1
2008-06-20
Effective Resistance Mismatch and Magnetoresistance of a CPP-GMR system with Current-Confined-Paths
We theoretically study the magnetoresistance of a CPP-GMR system with current confined paths (CCP) in the framework of Valet-Fert theory. The continuity equations for charge and spin currents are numerically solved with the three-dimensional CCP geometry by use of finite element method. It is confirmed that the MR rati...
0806.3314v1
2008-06-26
Negative differential resistance in molecular junctions: The effect of the electrodes electronic structure
We have carried out calculations of electron transport through a metal-molecule-metal junction with metal nanoclusters taking the part of electrodes. We show that negative differential resistance peaks could appear in the current-voltage curves. The peaks arise due to narrow features in the electron density of states o...
0806.4397v2
2008-10-07
Huge anisotropic magneto-resistance in iridium atomic chains
We analyze in this article the magneto-resistance ratio of finite and infinite iridium and platinum chains. Our calculations, that are based on a combination of non equilibrium Green function techniques and density functional theory, include a fully self-consistent treatment of non-collinear magnetism and of the spin-o...
0810.1170v1
2008-10-22
Itinerant Ferromagnetism in the electronic localization limit
We present Hall effect, $R_{xy}(H)$, and magnetoresistance, $R_{xx}(H)$, measurements of ultrathin films of Ni, Co and Fe with thicknesses varying between 0.2-8 nm and resistances between 1 M$\Omega$ - 100 $\Omega.$ Both measurements show that films having resistance above a critical value, $R_{C}$, (thickness below a ...
0810.4081v2
2008-11-06
Connectivity and Critical Currents in Polycrystalline MgB2
Current transport in polycrystalline magnesium diboride is highly non-uniform (percolative) due to the presence of secondary phases and also due to the intrinsic anisotropy of the material. The influence of secondary phases on the transport properties of MgB2 was investigated. Bulk samples were prepared from a mixture ...
0811.0986v1
2008-12-02
Independent magnetization behavior of a ferromagnetic metal/semiconductor hybrid system
We report the discovery of an effect where two ferromagnetic materials, one semiconductor ((Ga,Mn)As) and one metal (permalloy), can be directly deposited on each other and still switch their magnetization independently. We use this independent magnetization behavior to create various resistance states dependent on the...
0812.0455v1
2009-03-31
Proper Scaling of the Anomalous Hall Effect
Working with epitaxial films of Fe, we succeeded in independent control of different scattering processes in the anomalous Hall effect. The result appropriately accounted for the role of phonons, thereby clearly exposing the fundamental flaws of the standard plot of the anomalous Hall resistivity versus longitudinal re...
0903.5360v1
2009-04-08
Negative differential resistance in nanoscale transport in the Coulomb blockade
Motivated by recent experiments, we have studied transport behavior of coupled quantum dot systems in the Coulomb blockade regime using the master (rate) equation approach. We explore how electron-electron interactions in a donor-acceptor system, resembling weakly coupled quantum dots with varying charging energy, can ...
0904.1335v1
2009-05-18
On the origin of the electric carrier concentration in graphite
We investigate the dependence of the electrical resistivity of $\sim 60 $nm thick single crystalline graphite samples on the defect concentration produced by proton irradiation at very low fluences. We show that the resistivity decreases few percent at room temperature after inducing defects at concentrations as low as...
0905.2945v2
2009-06-18
Temperature-dependent resistivity of ferromagnetic GaMnAs: Interplay between impurity scattering and many-body effects
The static conductivity of the dilute magnetic semiconductor GaMnAs is calculated using the memory function formalism and time-dependent density-functional theory to account for impurity scattering and to treat Hartree and exchange interactions within the hole gas. We find that the Coulomb scattering off the charged im...
0906.3526v1
2009-09-11
Kinetic Friction by a Small Number of Intervening Inelastic Particles between Rough Surfaces
We investigate a mechanism of the appearance of kinetic friction in granular materials. We consider a small number of intervening inelastic particles between two rough surfaces as one of the simplest dynamical models to study granular friction. The resistance force applied to the upper surface is numerically calculated...
0909.2132v1
2009-10-13
Superconductivity of FeSe0.5Te0.5 Thin Films Grown by Pulsed Laser Deposition
FeSe0.5Te0.5 thin films with PbO-type structure are successfully grown on MgO(100) and LaSrAlO4(001) substrates from FeSe0.5Te0.5 or FeSe0.5Te0.75 polycrystalline targets by pulsed-laser deposition. The film deposited on the MgO substrate (film thickness ~ 55 nm) shows superconductivity at 10.6 K (onset) and 9.2 K (zer...
0910.2301v1
2010-01-25
Evidence for effective thermal boundary resistance from magnon/phonon disequilibrium
We use the time-resolved magneto-optical Kerr effect (TRMOKE) to measure the local temperature and heat flow dynamics in ferromagnetic SrRuO3 thin films. After heating by a pump pulse, the film temperature decays exponentially, indicating that the heat flow out of the film is limited by the film/substrate interface. We...
1001.4557v1