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2000-03-14
Magnetic and electrical resistance behaviour of the oxides, Ca$_{3-x}$Y$_x$LiRuO$_6$ (x= 0.0, 0.5 and 1.0)
We have investigated the magnetic and electrical resistance behaviour of Ca$_{3-x}$Y$_x$LiRuO$_6$. The parent compound exhibits magnetic ordering from Ru sublattice at a rather high temperature, 113 K. Though the paramagnetic Curie temperature ($\theta$$_p$) is negative indicative of antiferromagnetic ordering, the...
0003227v1
2001-03-26
Superconducting Mg-B films by pulsed laser deposition in an in-situ two-step process using multi-component targets
Superconducting thin films have been prepared in a two-step in-situ process, using the Mg-B plasma generated by pulsed laser ablation. The target was composed of a mixture of Mg and MgB2 powders to compensate for the volatility of Mg and therefore to ensure a high Mg content in the film. The films were deposited at tem...
0103543v1
2001-05-29
Growth, structure analysis and anisotropic superconducting properties of MgB2 single crystals
Here we report the growth of sub-millimeter MgB2 single crystals of various shapes under high pressure in Mg-B-N system. Structure refinement using a single-crystal X-ray diffraction analysis gives lattice parameters a=3.0851(5) A and c=3.5201(5) A with small reliability factors (Rw =0.025, R=0.018), which enables us t...
0105545v2
2001-10-18
Strong Quasiparticle Trapping In A 6x6 Array Of Vanadium-Aluminum Superconducting Tunnel Junctions
A 6x6 array of symmetrical V/Al/AlOx/Al/V Superconducting Tunnel Junctions (STJs) was fabricated. The base electrode is a high quality epitaxial film with a residual resistance ratio (RRR) of ~30. The top film is polycrystalline with an RRR of ~10. The leakage currents of the 25x25 mm^2 junctions are of the order of 0....
0110374v1
2001-10-18
Magnetic and transport properties of the new antiferromagnetic Kondo-lattice CeNiBi2
We report results of the first studies on the magnetic and transport properties of a new material CeNiBi_2. The magnetic susceptibility exhibits a sharp peak at T_N = 6K, indicating an antiferromagnetic phase transition. This antiferromagnetic order below T_N is confirmed by magnetization measurement, which displays a ...
0110380v1
2002-03-08
Strain effect on electronic transport and ferromagnetic transition temperature in La$_{0.9}$Sr$_{0.1}$MnO$_{3}$ thin films
We report on a systematic study of strain effects on the transport properties and the ferromagnetic transition temperature $T_{c}$ of high-quality La$_{0.9}$Sr$_{0.1}$MnO$_{3}$ thin films epitaxially grown on (100) SrTiO$_{3}$ substrates. Both the magnetization and the resistivity are critically dependent on the film t...
0203196v1
2002-04-22
Role of Umklapp Processes in Conductivity of Doped Two-Leg Ladders
Recent conductivity measurements performed on the hole-doped two-leg ladder material $\mathrm{Sr_{14-x}Ca_xCu_{24}O_{41}}$ reveal an approximately linear power law regime in the c-axis DC resistivity as a function of temperature for $x=11$. In this work, we employ a bosonic model to argue that umklapp processes are res...
0204485v1
2002-07-02
Comment to the paper : Collapse of the vortex-lattice inductance and shear modulus at the melting transition in untwinned YBa$_2$Cu$_3$O$_7$, by Matl \QTR{em}{et al.}
In a recent paper, Matl et al present a high-frequency study of the complex resistivity of a pinned vortex lattice in YBaCuO . They focus on the inductive-to-resistive transition which is investigated as a function of temperature at a constant field $B_0=2$ T, so that the transition is associated with the vanishing of ...
0207074v1
2003-05-21
Carbon-substituted MgB2 single crystals
Carbon-substituted MgB2 single crystals, Mg(B_1-xC_x)_2 of 0.3-1.0 mm size were grown for x=0.02-0.15 by a high-pressure technique. The doping dependence of lattice constants studied in a range of x=0.0-0.2 shows a monotonic decrease in a, while the c parameter remains almost invariant. Using X-ray diffraction and Auge...
0305485v1
2003-07-01
Efficient nonlinear room-temperature spin injection from ferromagnets into semiconductors through a modified Schottky barrier
We suggest a consistent microscopic theory of spin injection from a ferromagnet (FM) into a semiconductor (S). It describes tunneling and emission of electrons through modified FM-S Schottky barrier with an ultrathin heavily doped interfacial S layer . We calculate nonlinear spin-selective properties of such a reverse-...
0307030v4
2003-12-23
1-D Simulation of the Electron Density Distribution in a Novel Nonvolatile Resistive Random Access Memory Device
The operation of a novel nonvolatile memory device based on a conductive ferroelectric/non-ferroelectric thin film multilayer stack is simulated numerically. The simulation involves the self-consistent steady state solution of Poisson's equation and the transport equation for electrons assuming a Drift-Diffusion transp...
0312609v1
2004-03-08
Hole mobility in organic single crystals measured by a "flip-crystal" field-effect technique
We report on single crystal high mobility organic field-effect transistors (OFETs) prepared on prefabricated substrates using a "flip-crystal" approach. This method minimizes crystal handling and avoids direct processing of the crystal that may degrade the FET electrical characteristics. A chemical treatment process fo...
0403210v1
2004-04-11
Synthesis of as-grown superconducting MgB_2 thin films by molecular beam epitaxy in UHV conditions
As-grown superconducting MgB_2 thin films have been grown on SrTiO_3(001), MgO(001), and Al_2O_3(0001) substrates by a molecular beam epitaxy (MBE) method with novel co-evaporation conditions of low deposition rate in ultra-high vacuum. The structural and physical properties of the films were studied by RHEED, XRD, ele...
0404252v1
2004-08-20
Anomalous Hall effect in insulating Ga1-xMnxAs
We have investigated the effect of doping by Te on the anomalous Hall effect in Ga1-xMnxAs (x = 0.085). For this relatively high value of x the temperature dependence of resistivity shows an insulating behavior. It is well known that in Ga1-xMnxAs the Mn ions naturally act as acceptors. Additional doping by Te donors d...
0408446v1
2005-01-14
Magnetization and magnetoresistance in insulating phases of SrFeO3-d
We report the synthesis and properties of two new insulating phases of SrFeO3-d with introduction of oxygen deficiencies in metallic SrFeO3 ; one with 0.15 < d < 0.19 (sample A)and the other above d = 0.19 (sample B). Sample A shows large negative magnetoresistance around the charged ordering (CO) temperature with magn...
0501352v1
2005-07-14
Field-Dependent Hall Effect in Single Crystal Heavy Fermion YbAgGe below 1K
We report the results of a low temperature (T >= 50 mK) and high field (H <= 180 kOe) study of the Hall resistivity in single crystals of YbAgGe, a heavy fermion compound that demonstrates field-induced non-Fermi-liquid behavior near its field-induced quantum critical point. Distinct features in the anisotropic, field-...
0507338v1
2005-10-20
Stick slip motion in grain grain friction in a humid atmosphere
We set up an original apparatus to measure the grain grain friction stress inside a granular medium composed of sodo-silicate-glass beads surrounded by a water vapor atmosphere.We analyze here the influence of the physico chemistry of water on our glass beads and its consequences on our shear experiment. We found two s...
0510532v1
2006-06-23
Electronic transport in Si nanowires: Role of bulk and surface disorder
We calculate the resistance and mean free path in long metallic and semiconducting silicon nanowires (SiNWs) using two different numerical approaches: A real space Kubo method and a recursive Green's function method. We compare the two approaches and find that they are complementary: depending on the situation a prefer...
0606600v1
2006-07-18
Dielectric breakdown in underoxidized magnetic tunnel junctions: Dependence on oxidation time and area
Magnetic tunnel junctions (MTJs) with partially oxidized 9 \AA AlO$_x$-barriers were recently shown to have the necessary characteristics to be used as magnetoresistive sensors in high-density storage devices. Here we study dielectric breakdown in such underoxidized magnetic tunnel junctions, focusing on its dependence...
0607452v1
2007-01-20
Fabrication and Low Temperature Thermoelectric Properties of Na_xCoO_2 (x = 0.68 and 0.75) Epitaxial Films by the Reactive Solid-Phase Epitaxy
We have fabricated Na_xCoO_2 thin films via lateral diffusion of sodium into Co_3O_4 (111) epitaxial films (reactive solid-phase epitaxy: Ref. 4). The environment of thermal diffusion is key to the control of the sodium content in thin films. From the results of x-ray diffraction and in-plane resistivity, the epitaxial...
0701492v1
2007-02-05
Existence of two electronic states in Sr4Ru3O10 at low temperatures
We report measurements on in-plane resistivity, thermopower, and magnetization as a function of temperature and magnetic fields on single crystalline Sr4Ru3O10 grown by the floating zone method. As the temperature was lowered to below around 30 K, the in-plane and c-axis resistivities and the thermopower were found to ...
0702093v1
2007-05-02
Comment on ``Collapse of Coherent Quasiparticle States in $θ$-(BEDT-TTF)$_2$I$_3$ Observed by Optical Spectroscopy''
Recently, Takenaka et al. reported that the resistivity rho(T) of theta-(BEDT-TTF)_2I_3 (theta-ET) exceeds the Ioffe-Regel resistivity by a factor of 50 at large temperatures T (``bad metal''). This was ascribed to strong correlation. We argue that the optical conductivity sigma(omega) implies that correlation is not v...
0705.0230v1
2007-07-15
Physical properties of a new cuprate superconductor Pr_2Ba_4Cu_7O_{15-δ}
We present studies of the thermal, magnetic and electrical transport properties of reduced polycrystalline Pr_2Ba_4Cu_7O_{15-\delta} (Pr247) showing a superconducting transition at Tc = 10 - 16 K and compare them with those of as-sintered non-superconducting Pr247. The electrical resistivity in the normal state exhibit...
0707.2180v1
2007-07-30
Intrinsic tunneling in phase separated manganites
We present evidence of direct electron tunneling across intrinsic insulating regions in sub-micrometer wide bridges of the phase separated ferromagnet (La,Pr,Ca)MnO$_3$. Upon cooling below the Curie temperature, a predominantly ferromagnetic supercooled state persists where tunneling across the intrinsic tunnel barrier...
0707.4411v2
2008-01-09
Impact of in-plane currents on magnetoresistance properties of an exchange-biased spin-valve with insulating antiferromagnetic layer
The impact of in-plane alternating currents on the exchange bias, resistance, and magnetoresistance of a CoFe/NiCoO/CoFe/Cu/CoFe spin-valve is studied. With increasing current, the resistance is increased while the maximum magnetoresistance ratio decreases. Noticeably, the reversal of the pinned layer is systematically...
0801.1515v1
2008-04-09
Curie point singularity in the temperature derivative of resistivity in (Ga,Mn)As
We observe a singularity in the temperature derivative $d\rho/dT$ of resistivity at the Curie point of high-quality (Ga,Mn)As ferromagnetic semiconductors with $T_c$'s ranging from approximately 80 to 185 K. The character of the anomaly is sharply distinct from the critical contribution to transport in conventional den...
0804.1578v2
2008-06-24
Low temperature thermal resistance for a new design of silver sinter heat exchanger
We have developed a novel procedure for constructing high surface area silver sinter heat exchangers. Our recipe incorporates nylon fibers having a diameter of ~ 50 microns and thin wires of bulk silver in the heat exchanger. In order to increase the thermal conductance of liquid helium within the heat exchanger, prior...
0806.3930v1
2008-08-09
Transport and Magnetic properties of Fe1/3VSe2
Electrical conductivity, thermopower and magnetic properties of Fe-intercalated Fe0.33VSe2 has been reported between 4.2K - 300K. We observe a first order transition in the resistivity of the sintered pellets around 160K on cooling. The electronic properties including the transitional hysteresis in the resistance anoma...
0808.1334v1
2008-08-28
Giant frictional drag in strongly interacting bilayers near filling factor one
We study the frictional drag in high mobility, strongly interacting GaAs bilayer hole systems in the vicinity of the filling factor $\nu=1$ quantum Hall state (QHS), at the same fillings where the bilayer resistivity displays a reentrant insulating phase. Our measurements reveal a very large longitudinal drag resistivi...
0808.3807v1
2008-10-26
Development of Glass Resistive Plate Chambers for INO
The India-based Neutrino Observatory (INO) collaboration is planning to build a massive 50kton magnetised Iron Calorimeter (ICAL) detector, to study atmospheric neutrinos and to make precision measurements of the parameters related to neutrino oscillations. Glass Resistive Plate Chambers (RPCs) of about 2m X 2m in size...
0810.4693v1
2009-02-01
Enhancement of positive magnetoresistance following a magnetic-field-induced ferromagnetic transition in an intermetallic compound, Tb5Si3
We report the existence of a field-induced ferromagnetic transition in the magnetically ordered state (<69 K) of an intermetallic compound, Tb5Si3, and this transition is distinctly first-order at 1.8 K (near 60 kOe), whereas it appears to become second order near 20 K. The finding we stress is that the electrical resi...
0902.0153v1
2009-06-08
Tunneling Electroresistance in Ferroelectric Tunnel Junctions with a Composite Barrier
Tunneling electroresistance (TER) effect is the change in the electrical resistance of a ferroelectric tunnel junction (FTJ) associated with polarization reversal in the ferroelectric barrier layer. Here we predict that a FTJ with a composite barrier that combines a functional ferroelectric film and a thin layer of a n...
0906.1524v1
2009-08-11
Contrasting Pressure Effects in Sr2VFeAsO3 and Sr2ScFePO3
We report the resistivity measurements under pressure of two Fe-based superconductors with a thick perovskite oxide layer, Sr2VFeAsO3 and Sr2ScFePO3. The superconducting transition temperature Tc of Sr2VFeAsO3 markedly increases with increasing pressure. Its onset value, which was Tc{onset}=36.4 K at ambient pressure, ...
0908.1469v2
2010-03-11
Nonlinear response and two stable electrical conductivity levels measured in plasticized PVC thin film samples
The electrical conductivity of PVC films prepared with a patented plasticizer of type "A" was measured with high precision automated setup, based on standard ring sell with a voltage range much less than breakdown voltage. Continual voltage-current measurements permit to take into account Debay relaxation process and c...
1003.2331v1
2010-09-13
Non-monotonic temperature dependent transport in graphene grown by Chemical Vapor Deposition
Temperature-dependent resistivity of graphene grown by chemical vapor deposition (CVD) is investigated. We observe in low mobility CVD graphene device a strong insulating behavior at low temperatures and a metallic behavior at high temperatures manifesting a non-monotonic in the temperature dependent resistivity.This f...
1009.2506v2
2010-10-14
Viscous corrections to the resistance of nano-junctions: a dispersion relation approach
It is well known that the viscosity of a homogeneous electron liquid diverges in the limits of zero frequency and zero temperature. A nanojunction breaks translational invariance and necessarily cuts off this divergence. However, the estimate of the ensuing viscosity is far from trivial. Here, we propose an approach ba...
1010.2959v2
2011-05-18
Multiple photoexcitation of two-dimensional electron systems: bichromatic magnetoresistance oscillations revisited
We analyze theoretically magnetoresistance of high mobility two-dimensional electron systems being illuminated by multiple radiation sources. In particular, we study the influence on the striking effect of microwave-induced resistance oscillations. We consider moderate radiation intensities without reaching the zero re...
1105.3592v1
2011-07-11
Impairment of double exchange mechanism in electron transport of iron pnictides
Double exchange mechanism is believed to favor transport along ferromagnetic directions, the failure of which in explaining the unusual resistivity anisotropy in iron pnictides is investigated. Several factors intrinsic to the microscopic mechanism of transport in iron pnictides are identified and analyzed, including t...
1107.1952v1
2011-10-24
Anisotropy of upper critical fields and thermally-activated flux flow of quenched KxFe2-ySe2 single crystals
We report the anisotropy of the upper critical fields mu0Hc2(T) and thermally-activated flux flow (TAFF) behavior of quenched KxFe2-ySe2. Even though the post-annealing and quenching process enhances the superconducting volume fraction, it has a minor effect on the upper critical fields for H//c and H//ab. Analysis of ...
1110.5316v1
2011-10-26
Mg substitution in CuCrO2 delafossite compounds
A detailed investigation of the series CuCr(1-x)MgxO2 (x = 0.0 - 0.05) has been performed by making high-temperature resistivity and thermopower measurements, and by performing a theoretical analysis of the latter. Microstructure characterization has been carried out as well. Upon Mg2+ for Cr3+ substitution, a concomit...
1110.5730v2
2011-11-09
Insulator-to-metal transition and large thermoelectric effect in La$_{1-x}$Sr$_{x}$MnAsO
We report the Sr substitution effect in an antiferromagnetic insulator LaMnAsO. The Sr doping limit is $x\sim$ 0.10 under the synthesis conditions, as revealed by x-ray diffractions indicate. Upon Sr doping, the room-temperature resistivity drops by five orders of magnitude down to $\sim$0.01 $\Omega\cdot$cm, and the t...
1111.2232v1
2011-11-23
Magneto-Electric Effects on Sr Z-type Hexaferrite at Room Temperature
In this paper, magnetoelectric effects of Sr Z-type hexaferrite, Sr3Fe24Co2O41, at room temperature is measured. The change in remanence magnetization was measured by applying a DC voltage or electric field across a slab of hexaferrite. Changes of ~ 18% in remanence was observed in an electric field of 10,000V/cm imply...
1111.5555v1
2011-11-23
Room Temperature Magnetoelectric Effects on Single Slabs of Z-type Hexaferrites
In this paper, magnetoelectric effects of Sr Z-type hexaferrite, Sr3Fe24Co2O41, at room temperature is measured. The change in remanence magnetization was measured by applying a DC voltage or electric field across a slab of hexaferrite. Changes of ~ 18% in remanence was observed in an electric field of 10,000V/cm imply...
1111.5556v1
2012-02-05
Temperature dependent elastic constants and ultimate strength of graphene and graphyne
Based on the first principles calculation combined with quasi-harmonic approximation, in this work we focus on the analysis of temperature dependent lattice geometries, thermal expansion coefficients, elastic constants and ultimate strength of graphene and graphyne. For the linear thermal expansion coefficient, both gr...
1202.0933v1
2012-02-08
Coexisting Holes and Electrons in High-Tc Materials: Implications from Normal State Transport
Normal state resistivity and Hall effect are shown to be successfully modeled by a two-band model of holes and electrons that is applied self-consistently to (i) DC transport data reported for eight bulk-crystal and six oriented-film specimens of YBa2Cu3O7-{\delta}, and (ii) far-infrared Hall angle data reported for YB...
1202.1792v1
2012-07-25
Superconductivity at 5.4 K in $β$-Bi$_2$Pd
We investigate bulk superconductivity in a high-quality single crystal of Bi$_2$Pd ($\beta$-Bi$_2$Pd, space group; I4/mmm) at temperatures less than 5.4 K by exploring its electrical resistivity, magnetic susceptibility, and specific heat. The temperature dependence of the electrical resistivity shows convex-upward beh...
1207.5905v3
2012-10-09
Giant exchange bias and ferromagnetism in the CoO shell of Co/CoO-MgO core-shell nanoparticles
Using magnetron sputtering, we produced a series of Co/CoO-MgO nanoparticles on Si(100) substrates. High-resolution transmission electron microscopy (HRTEM) image shows that small isolated Co-clusters (core) covered with CoO (shells) with a size of a few nm embedded in a MgO matrix. Resistivity as a function of Co atom...
1210.2510v1
2012-11-12
Density dependent electrical conductivity in suspended graphene: Approaching the Dirac point in transport
We theoretically consider, comparing with the existing experimental literature, the electrical conductivity of gated monolayer graphene as a function of carrier density, temperature, and disorder in order to assess the prospects of accessing the Dirac point using transport studies in high-quality suspended graphene. We...
1211.2845v2
2012-12-26
Molybdenum sputtering film characterization for high gradient accelerating structures
Technological advancements are strongly required to fulfill the demands of new accelerator devices with the highest accelerating gradients and operation reliability for the future colliders. To this purpose an extensive R&D regarding molybdenum coatings on copper is in progress. In this contribution we describe chemica...
1212.6203v1
2012-12-28
Magneto-resistance up to 60 Tesla in Topological Insulator Bi2Te3 Thin Films
We report magneto-transport studies of topological insulator Bi_{2}Te_{3} thin films grown by pulsed laser deposition. A non-saturating linear-like magneto-resistance (MR) is observed at low temperatures in the magnetic field range from a few Tesla up to 60 Tesla. We demonstrate that the strong linear-like MR at high f...
1212.6464v1
2013-01-02
Visualizing Atomic-Scale Negative Differential Resistance in Bilayer Graphene
We investigate the atomic-scale tunneling characteristics of bilayer graphene on silicon carbide using the scanning tunneling microscopy. The high-resolution tunneling spectroscopy reveals an unexpected negative differential resistance (NDR) at the Dirac energy, which spatially varies within the single unit cell of bil...
1301.0270v1
2013-04-01
Pressure Induced Superconductivity and Structural Transitions in Ba(Fe0.9Ru0.1)2As2
High pressure electrical resistance and x-ray diffraction measurements have been performed on ruthenium-doped Ba(Fe0.9Ru0.1)2As2, up to pressures of 32 GPa and down to temperatures of 10 K, using designer diamond anvils under quasi-hydrostatic conditions. At 3.9 GPa, there is an evidence of pressure-induced superconduc...
1304.0298v2
2013-04-10
Charge Kondo Effect in Thermoelectric Properties of Lead Telluride doped with Thallium Impurities
We investigate the thermoelectric properties of PbTe doped with a small concentration $x$ of Tl impurities acting as acceptors and described by Anderson impurities with negative on-site (effective) interaction. The resulting charge Kondo effect naturally accounts for a number of the low temperature anomalies in this sy...
1304.3026v1
2013-04-22
Modeling Composites of Multi-Walled Carbon Nanotubes in Polycarbonate
High strain rate experiments performed on multi-walled carbon nanotubes and polycarbonate composites (MWCNT-PC) have exhibited enhanced impact resistance under a dynamic strain rate of nearly 2500/s with composition of only 0.5 to 2.0 percent of Multi walled carbon nanotubes(MWCNTs) in pure polycarbonate(PC). Similarly...
1304.5979v1
2013-08-15
Suppression of bulk conductivity in InAs/GaSb broken gap composite quantum wells
The two-dimensional topological insulator state in InAs/GaSb quantum wells manifests itself by topologically protected helical edge channel transport relying on an insulating bulk. This work investigates a way of suppressing bulk conductivity by using gallium source materials of different degrees of impurity concentrat...
1308.3375v2
2013-09-06
Heteroepitaxy of Group IV-VI Nitrides by Atomic Layer Deposition
Heteroepitaxial growth of selected group IV-VI nitrides on various orientations of sapphire (\alpha-Al2O3) is demonstrated using atomic layer deposition. High quality, epitaxial films are produced at significantly lower temperatures than required by conventional deposition methods. Characterization of electrical and su...
1309.1789v1
2013-10-31
Single crystal growth and characterization of the large-unit-cell compound Cu13Ba
Single crystals of Cu$_{13}$Ba were successfully grown out of Ba-Cu self flux. Temperature dependent magnetization, $M(T)$, electrical resistivity, $\rho(T)$, and specific heat, $C_p(T)$, data are reported. Isothermal magnetization measurements, $M(H)$, show clear de Haas-van Alphen oscillations at $T$ = 2 K for applie...
1311.0027v1
2013-11-22
Thermally excited multi-band conduction in LaAlO3/SrTiO3 heterostructures exhibiting magnetic scattering
Magnetotransport measurements of charge carriers at the interface of a LaAlO3/SrTiO3 heterostructure with 26 unit cells of LaAlO3 show Hall resistance and magnetoresistance which at low and high temperatures is described by a single channel of electron-like charge carriers. At intermediate temperatures, we observe non-...
1311.5807v1
2014-04-18
Systematic control of carrier concentration and resisitivity in RF sputtered Zinc oxide thin films
RF sputtered ZnO and Al:ZnO films are attractive transparent conductive oxides for fabrication of opto-electronic devices. In this paper we present efforts to control carrier concentration and mobility of ZnO/Al:ZnO thin films by controlling deposition parameters (RF power, pressure and substrate temperature. Al:ZnO th...
1404.4902v1
2014-04-17
Caracterización de austenita expandida generada por cementación iónica de aceros inoxidables. Estudio de la estabilidad frente a la irradiación con haces de iones ligeros energéticos
This thesis was focused on the surface modification with plasma discharge. Austenitic AISI 316L stainless steel sample was carburised under different experimental conditions and mechanical properties have been studied (thickness, lattice parameter, elemental composition, hardness, wear resistance and corrosion resistan...
1404.5204v1
2014-05-05
Controllable growth of Al nanorods for inexpensive and degradation-resistant surface enhanced Raman spectroscopy
Surface enhanced Raman spectroscopy (SERS) has the capacity of detecting trace amount of biological or chemical matter, even single molecules, through the use of metallic nanostructures such as nanorods. Silver (Ag) and gold (Au) nanorods have led to the impressive enhancement of Raman signals, but they are either expe...
1405.1009v1
2014-06-27
Simulation of Non-linear SRF losses derived from characteristic topography of etched and electropolished niobium surfaces
A simplified numerical model has been developed to simulate non-linear superconducting radiofrequency (SRF) losses on Nb surfaces. This study focuses exclusively on excessive surface resistance (Rs) losses due to the microscopic topographical magnetic field enhancements. When the enhanced local surface magnetic field e...
1406.7276v4
2015-01-25
Superconductivity in Dense Rashba Semiconductor BiTeCl
Layered non-centrosymmetric bismuth tellurohalides are being examined as candidates for topological insulators. Pressure is believed to be essential for inducing and tuning topological order in these systems. Through electrical transport and Raman scattering measurements, we find superconductivity in two high-pressure ...
1501.06203v1
2015-02-04
Topological Insulator Thin Films Starting from the Amorphous Phase - Bi$_2$Se$_3$ as Example
We present a new method to obtain topological insulator Bi$_2$Se$_3$ thin films with a centimeter large lateral length. To produce amorphous Bi$_2$Se$_3$ thin films we have used a sequential flash-evaporation method at room temperature. Transmission electron microscopy has been used to verify that the prepared samples ...
1502.01135v1
2015-03-13
Suspended graphene devices with local gate control on an insulating substrate
We present a fabrication process for graphene-based devices where a graphene monolayer is suspended above a local metallic gate placed in a trench. As an example we detail the fabrication steps of a graphene field-effect transistor. The devices are built on a bare high-resistivity silicon substrate. At temperatures of ...
1503.04147v2
2015-03-18
A novel fast timing micropattern gaseous detector: FTM
In recent years important progress in micropattern gaseous detectors has been achieved in the use of resistive material to build compact spark-protected devices. The novel idea presented here consists of the polarisation of WELL structures using only resistive coating. This allows a new device to be built with an archi...
1503.05330v1
2015-10-19
High resolution Hall measurements across the VO2 metal-insulator transition reveal impact of spatial phase separation
Many strongly correlated transition metal oxides exhibit a metal-insulator transition (MIT), the manipulation of which is essential for their application as active device elements. However, such manipulation is hindered by lack of microscopic understanding of mechanisms involved in these transitions. A prototypical exa...
1510.05414v1
2016-02-12
Relaxation of the resistive superconducting state in boron-doped diamond films
We report a study of the relaxation time of the restoration of the resistive superconducting state in single crystalline boron-doped diamond using amplitude-modulated absorption of (sub-)THz radiation (AMAR). The films grown on an insulating diamond substrate have a low carrier density of about 2.5x10^{21} cm^{-3} and ...
1602.04046v1
2016-05-12
Scalable, ultra-resistant structural colors based on network metamaterials
Structural colours have drawn wide attention for their potential as a future printing technology for various applications, ranging from biomimetic tissues to adaptive camouflage materials. However, an efficient approach to realise robust colours with a scalable fabrication technique is still lacking, hampering the real...
1605.03700v1
2016-08-02
Low-energy electron-irradiation effect on transport properties of graphene field effect transistor
We study the effects of low-energy electron beam irradiation up to 10 keV on graphene based field effect transistors. We fabricate metallic bilayer electrodes to contact mono- and bi-layer graphene flakes on SiO$_2$, obtaining specific contact resistivity $\rho_c \simeq 19 k\Omega \mu m^2$ and carrier mobility as high ...
1608.00716v1
2016-08-23
Disorder effect on the anisotropic resistivity of phosphorene determined by a tight-binding model
In this work we develop a compact multi-orbital tight-binding model for phosphorene that accurately describes states near the main band gap. The model parameters are adjusted using as reference the band structure obtained by a density-functional theory calculation with the hybrid HSE06 functional. We use the optimized ...
1608.06633v2
2016-10-21
Giant Positive Magnetoresistance and field-induced metal insulator transition in Cr2NiGa
We report here the magneto-transport properties of the newly synthesized Heusler compound Cr2NiGa which crystallizes in a disordered cubic B2 structure belonging to Pm-3m space group. The sample is found to be paramagnetic down to 2 K with metallic character. On application of magnetic field, a significantly large incr...
1610.06771v1
2017-02-08
Hall field-induced resistance oscillations in MgZnO/ZnO heterostructures
We report on nonlinear magnetotransport in a two-dimensional electron gas hosted in a MgZnO/ZnO heterostructure. Upon application of a direct current, we observe pronounced Hall field-induced resistance oscillations (HIRO) which are well known from experiments on high-mobility GaAs/AlGaAs quantum wells. The unique sens...
1702.02557v1
2017-02-22
Variable-range-hopping conduction processes in oxygen deficient polycrystalline ZnO films
We have fabricated oxygen deficient polycrystalline ZnO films by the rf sputtering deposition method. To systematically investigate the charge transport mechanisms in these samples, the electrical resistivities have been measured over a wide range of temperature from 300 K down to liquid-helium temperatures. We found t...
1702.06729v1
2017-06-25
Coherent Interlayer Tunneling and Negative Differential Resistance with High Current Density in Double Bilayer Graphene-WSe2 Heterostructures
We demonstrate gate-tunable resonant tunneling and negative differential resistance between two rotationally aligned bilayer graphene sheets separated by bilayer WSe2. We observe large interlayer current densities of 2 uA/um2 and 2.5 uA/um2, and peak-to-valley ratios approaching 4 and 6 at room temperature and 1.5 K, r...
1706.08034v1
2017-09-08
Coulomb drag and counterflow Seebeck coefficient in bilayer-graphene double layers
We have fabricated bilayer-graphene double layers separated by a thin ($\sim$20 nm) boron nitride layer and performed Coulomb drag and counterflow thermoelectric transport measurements. The measured Coulomb drag resistivity is nearly three orders smaller in magnitude than the intralayer resistivities. The counterflow S...
1709.02778v1
2017-11-05
Synthesis of sodium cobaltate Na$_{x}$CoO$_{2}$ single crystals with controlled Na ordering
In this study, we synthesized single crystals of Na$_{x}$CoO$_{2}$ with $x\sim0.8$ using the optical floating zone technique. A thorough electrochemical treatment of the samples permitted us to control the de-intercalation of Na to obtain single crystal samples of stable Na ordered phases with $x=0.5-0.8$. Comparisons ...
1711.01611v2
2018-01-19
Nontrivial Metallic State of Molybdenum Disulfide
The electrical conductivity and Raman spectroscopy measurements have been performed on MoS$_2$ at high pressures up to 90 GPa and variable temperatures down to 5 K. We find that the temperature dependence of the resistance in a metallic 2H$_a$ phase has an anomaly (a hump) which shifts with pressure to higher temperatu...
1801.06351v1
2019-05-23
Laser machined ultrathin microscale platinum thermometers on transparent oxide substrates
Ultrathin microscale resistive thermometers are of key value to many applications. Here we have fabricated a laser machined 50 ${\mu}$m wide and 50 nm thick serpentine Pt thin film sensor capable of sensing temperatures up to 650 ${^\circ}$ C over multiple heating and cooling cycles. Various materials and associated pr...
1905.09812v1
2014-08-06
Desarrollo de capas de AlN sobre aleaciones de aluminio como protección superficial contra la corrosión y el desgaste
Aluminum and their alloys, after careful treatments, can develop excellent mechanical, tribological, electrical and chemical (high corrosion resistance) properties. However, 7000 series, with Cu in the alloy, have a poor corrosion resistance. On the other hand, aluminum nitride (AlN) has a wurtzitic phase and good ther...
1408.1378v1
2014-08-28
Magneto-Dielectric Behavior in $La_{0.53}Ca_{0.47}MnO_{3}$
We prospect magneto-dielectricity in $La_{0.53}Ca_{0.47}MnO_{3}$ across its paramagnetic (PMI) to ferromagnetic (FMM) isostructural transition at $T_{C} \sim 253K$, by magnetic ($(M)$), caloric ($(W)$), dielectric ($(\epsilon')$), magneto-resistive (MR), and magneto-capacitance (MC) investigations. Skew-broadened first...
1408.6640v2
2017-03-02
Thermal conduction across a boron nitride and silicon oxide interface
The needs for efficient heat removal and superior thermal conduction in nano/micro devices have triggered tremendous studies in low-dimensional materials with high thermal conductivity. Hexagonal boron nitride (h-BN) is believed to be one of the candidates for thermal management and heat dissipation due to its novel ph...
1703.00669v1
2019-02-10
The role of plastic strain gradients in the crack growth resistance of metals
Crack advance from short or long pre-cracks is predicted by the progressive failure of a cohesive zone in a strain gradient, elasto-plastic solid. The presence of strain gradients leads to the existence of an elastic zone at the tip of a stationary crack, for both the long crack and the short crack cases. This is in sh...
1902.03664v1
2019-07-11
Impurity concentration dependent electrical conduction in germanium crystal at low temperatures
Germanium single crystal having 45 mm diameter and 100 mm length of 7N+ purity has been grown by Czochralski method. Structural quality of the crystal has been characterized by Laue diffraction. Electrical conduction and Hall measurements are carried out on samples retrieved from different parts of the crystal along th...
1907.05067v1
2020-02-25
Non-invasive nanoscale potentiometry and ballistic transport in epigraphene nanoribbons
The recent observation of non-classical electron transport regimes in two-dimensional materials has called for new high-resolution non-invasive techniques to locally probe electronic properties. We introduce a novel hybrid scanning probe technique to map the local resistance and electrochemical potential with nm- and $...
2002.11024v1
2020-04-07
Multi-terminal electronic transport in boron nitride encapsulated TiS$_3$ nanosheets
We have studied electrical transport as a function of carrier density, temperature and bias in multi-terminal devices consisting of hexagonal boron nitride (h-BN) encapsulated titanium trisulfide (TiS$_3$) sheets. Through the encapsulation with h-BN, we observe metallic behavior and high electron mobilities. Below $\si...
2004.03687v1
2020-04-09
Magnetic field-dependent resistance crossover and logarithmic to non-saturating magnetoresistance in topological insulator Bi$_2$Te$_3$
We report a metal-insulator like transition in single crystalline 3D topological insulator Bi2Te3 at a temperature of 230K in presence of an external magnetic field applied normal to the surface. This transition becomes more prominent at larger magnetic field strength with the residual resistance value increasing linea...
2004.04375v2
2012-01-02
Magnetodielectric behavior in La2CoMnO6 nanoparticles
We have investigated magnetic, dielectric and magnetodielectric properties of La2CoMnO6 nanoparticles prepared by sol-gel method. Magnetization measurements revealed two distinct ferromagnetic transitions at 218 K and 135 K that can be assigned to ordered and disordered magnetic phases of the La2CoMnO6 nanoparticles. T...
1201.0448v1
2012-01-30
Unusual size effects on thermoelectricity in a strongly correlated oxide
We investigated size effects on thermoelectricity in thin films of a strongly correlated layered cobaltate. At room temperature, the thermopower is independent of thickness down to 6 nm. This unusual behavior is inconsistent with the Fuchs-Sondheimer theory, which is used to describe conventional metals and semiconduct...
1201.6274v1
2016-03-05
MIRO-like oscillations of magneto-resistivity in GaAs heterostructures induced by THz radiation
We report on the study of terahertz radiation induced MIRO-like oscillations of magneto-resistivity in GaAs heterostructures. Our experiments provide an answer on two most intriguing questions - effect of radiation helicity and the role of the edges - yielding crucial information for understanding of the MIRO origin. M...
1603.01760v1
2017-05-17
Epitaxial electrical contact to graphene on SiC
Establishing good electrical contacts to nanoscale devices is a major issue for modern technology and contacting 2D materials is no exception to the rule. One-dimensional edge-contacts to graphene were recently shown to outperform surface contacts but the method remains difficult to scale up. We report a resist-free an...
1705.08257v2
2017-07-10
Phonon-Driven Electron Scattering and Magnetothermoelectric Effect in Two-Dimensional Tin Selenide
The bulk tin selenide (SnSe) is the best thermoelectric material currently with the highest figure-of-merit due to the strong phonon-phonon interactions. We investigate the effect of electron-phonon coupling (EPC) on the transport properties of two-dimensional (2D) SnSe sheet. We demonstrate that EPC plays a key role i...
1707.02737v1
2019-03-05
Development of a time projection chamber with a sheet-resistor field cage
A new-concept time projection chamber (TPC) using a commercial resistive sheet, sheet-resistor micro-TPC SR-microPIC, was developed and its performance was measured. SR-microTPC has the potential to create a more uniform electric field than conventional TPCs with resistor-chains owing to its continuous sheet resistivit...
1903.01663v3
2019-03-30
Disentangling spin-orbit coupling and local magnetism in a quasi-two-dimensional electron system
Quantum interference between time-reversed electron paths in two dimensions leads to the well-known weak localization correction to resistance. If spin-orbit coupling is present, the resistance correction is negative, termed weak anti-localization (WAL). Here we report the observation of WAL coexisting with exchange co...
1904.00295v2
2019-08-27
Large surface conductance and two-dimensional superconductivity in microstructured crystalline topological insulators
Controllable geometric manipulation via micromachining techniques provides a promising tool for enhancing useful topological electrical responses relevant to future applications such as quantum information science. Here we present microdevices fabricated with focused ion beam from indium-doped topological insulator Pb1...
1908.10427v1
2019-12-11
Pressure-induced superconductivity and structural transition in ferromagnetic Cr2Si2Te6
The discovery of intrinsic magnetism in atomically thin two-dimensional transition-metal trichalcogenides has attracted intense research interest due to the exotic properties of magnetism and potential applications in devices. Pressure has proven to be an effective tool to manipulate the crystal and electronic structur...
1912.05166v1
2012-06-23
Molecular-beam epitaxial growth of a far-infrared transparent electrode for extrinsic Germanium photoconductors
We have evaluated the optical and electrical properties of a far-infrared (IR) transparent electrode for extrinsic germanium (Ge) photoconductors at 4 K, which was fabricated by molecular beam epitaxy (MBE). As a far-IR transparent electrode, an aluminum (Al)-doped Ge layer is formed at well-optimized doping concentrat...
1206.5368v1
2015-04-08
Post-growth purification of Co nanostructures prepared by focused electron beam induced deposition
In the majority of cases nanostructures prepared by focused electron beam induced deposition (FEBID) employing an organometallic precursor contain predominantly carbon-based ligand dissociation products. This is unfortunate with regard to using this high-resolution direct-write approach for the preparation of nanostruc...
1504.01945v1
2015-06-22
Preparation, characterization, and electrical properties of epitaxial NbO2 thin film lateral devices
Epitaxial NbO2 (110) films, 20 nm thick, were grown by pulsed laser deposition on Al2O3 (0001) substrates. The Ar/O2 total pressure during growth was varied to demonstrate the gradual transformation between NbO2 and Nb2O5 phases, which was verified using x-ray diffraction, x-ray photoelectron spectroscopy, and optical ...
1506.06640v2
2018-07-25
Galvanomagnetic properties of the putative type-II Dirac semimetal PtTe$_2$
Platinum ditelluride has recently been characterized, based on angle-resolved photoemission spectroscopy data and electronic band structure calculations, as a possible representative of type-II Dirac semimetals. Here, we report on the magnetotransport behavior (electrical resistivity, Hall effect) in this compound, inv...
1807.09876v1