publicationDate stringlengths 10 10 | title stringlengths 17 233 | abstract stringlengths 20 3.22k | id stringlengths 9 12 |
|---|---|---|---|
1999-03-15 | Metal-insulator transition in CMR materials | We report on resistivity measurements in La$_{0.67}$Ca$_{0.33}$MnO$_{3}$ and
Nd$_{0.7}$Sr$_{0.3}$MnO$_{3}$ thin films in order to elucidate the underlying
mechanism for the CMR behavior. The experimental results are analyzed in terms
of quantum phase transition ideas to study the nature of the metal-insulator
transitio... | 9903238v2 |
2000-01-06 | Time Dependent Effects and Transport Evidence for Phase Separation in La_{0.5}Ca_{0.5}MnO_{3} | The ground state of La_{1-x}Ca_{x}MnO_{3} changes from a ferromagnetic
metallic to an antiferromagnetic charge-ordered state as a function of Ca
concentration at x ~ 0.50. We present evidence from transport measurements on a
sample with x = 0.50 that the two phases can coexist, in agreement with other
observations of p... | 0001064v1 |
2000-02-14 | Transition Temperature and Magnetoresistance in Double-Exchange Compounds with Moderate Disorder | We develop a variational mean-field theory of the ferromagnetic transition in
compounds like Lanthanum-Manganite within the framework of the Double-Exchange
Model supplemented by modest disorder. We obtain analytical expressions for the
transition temperature, its variation with the valence electron-density and its
dec... | 0002191v1 |
2000-03-11 | Effect of γ-irradiation on superconducting transition temperature and resistive transition in polycrystalline YBa_{2}Cu_{3}O_(7-δ) | A bulk polycrystalline sample of YBa_(2)Cu_(3)O_(7-\delta) (\delta \approx
0.1) has been irradiated by \gamma-rays with ^{60}Co source. Non-monotonic
behavior of T_{c} with increasing irradiation dose \Phi (up to 220 MR) is
observed: T_{c} decreases at low doses (\Phi < 50 MR) from initial value
(\approx 93 K) by about... | 0003192v1 |
2000-06-07 | Step-wise Behavior of Vortex-Lattice Melting Transition in Tilted Magnetic Fields in Single Crystals Bi2Sr2CaCu2O8+d | The vortex lattice melting transition in single crystals Bi2Sr2CaCu2O8+d was
studied by the in-plane resistivity measurements in magnetic fields tilted away
from the c-axis to the ab-plane. In order to avoid the surface barrier effect
which hinders the melting transition in the conventional transport
measurements, we u... | 0006095v1 |
2000-08-07 | Large two-level magnetoresistance effect in doped manganite grain boundary junctions | We performed a systematic analysis of the tunneling magnetoresistance (TMR)
effect in single grain boundary junctions formed in epitaxial
La(2/3)Ca(1/3)MnO(3) films deposited on SrTiO(3) bicrystals. For magnetic
fields H applied parallel to the grain boundary barrier, an ideal two-level
resistance switching behavior wi... | 0008105v1 |
2000-10-20 | Composite Spin Waves, Quasi-Particles and Low Temperature resistivity in Double Exchange Systems | We make a quantum description of the electron low temperature properties of
double exchange materials. In these systems there is a strong coupling between
the core spin and the carriers spin. This large coupling makes the low energy
spin waves to be a combination of ion and electron density spin waves. We study
the for... | 0010312v1 |
2000-12-13 | Phase-coherence transition in granular superconductors with $π$ junctions | We study the three-dimensional XY-spin glass as a model for the resistive
behavior of granular superconductors containing a random distribution of $\pi$
junctions, as in high-$T_c$ superconducting materials with d-wave symmetry. The
$\pi$ junctions leads to quenched in circulating currents (chiralities) and to
a chiral... | 0012238v1 |
2000-12-19 | Resistance Spikes at Transitions between Quantum Hall Ferromagnets | We report a new manifestation of first-order magnetic transitions in
two-dimensional electron systems. This phenomenon occurs in aluminum arsenide
quantum wells with sufficiently low carrier densities and appears as a set of
hysteretic spikes in the resistance of a sample placed in crossed parallel and
perpendicular ma... | 0012367v1 |
2001-01-30 | Stress-induced metallic behavior under magnetic field in Pr$_{1-x}$Ca$_{x}$MnO$_{3}$ (x = 0.5 and 0.4) thin films | We have investigated the role of the stress-induced by the presence of the
substrate in thin films of colossal magnetoresistive manganites on structural,
resistive and magnetic properties. Because of the strong coupling between the
small structural distortions related to the charge-ordering (CO) and the
resistive prope... | 0101448v1 |
2001-04-18 | Electron Transport in Diborides: Observation of Superconductivity in ZrB2 | We report on syntheses and electron transport properties of polycrystalline
samples of diborides (AB2) with different transition metals atoms (A=Zr,Nb,Ta).
The temperature dependence of resistivity, \rho(T), and ac susceptibility of
these samples reveal superconducting transition of ZrB2 with Tc=5.5 K, while
NbB2 and T... | 0104323v1 |
2001-05-02 | In-plane Hall effect in c-axis-oriented MgB2 thin films | We have measured the longitudinal resistivity and the Hall resistivity in the
ab-plane of highly c-axis-oriented MgB2 thin films. In the normal state, the
Hall coefficient (R_H) behaves as R_H ~ T with increasing temperature (T) up to
130 K and then deviates from that linear T-dependence at higher temperatures.
The T^2... | 0105024v2 |
2001-05-04 | A New Method of Probing the Phonon Mechanism in Superconductors including MgB$_{2}$ | Weak localization has a strong influence on both the normal and
superconducting properties of metals. In particular, since weak localization
leads to the decoupling of electrons and phonons, the temperature dependence of
resistance (i.e., $\lambda_{tr}$) is decreasing with increasing disorder, as
manifested by Mooij's ... | 0105091v1 |
2002-01-25 | Degradation of LaMnO{3-y} surface layer in LaMnO{3-y}/ metal interface | We report electrical measurements showing the degradation processes of
LaMnO$_{3-y}$ (LaMnO) in LaMnO/normal metal interface in both point contact and
planar-type junctions. Immediately after the preparation of the interface, the
degradation process was followed by measuring the evolution of the junction
resistance ver... | 0201460v1 |
2002-02-06 | Thermoelectric properties of the brownmillerite oxide Ca_{2-y}La_yCo_{2-x}Al_xO_5 | We prepared the brownmillerite oxide Ca_{2-y}La_yCo_{2-x}Al_xO_5, and found
that it was an n-type conductor. The thermopower and the resistivity of the
single crystal are -90 microV/K and 68 mOhm cm along the ab direction at 440 K,
which suggest relatively good thermoelectrical properties, compared with other
transitio... | 0202087v1 |
2002-04-29 | Concentration of Charge Carriers and Anomalous Gap Parameter in the Normal State of High-$T_c$ Superconductors | Fermi-Dirac statistics has been utilized by introducing the average
ionization energy ($E_I$) as an additional anomalous energy gap in order to
derive the two-dimensional concentration of charge carriers and the
phenomenological resistivity model for the superconducting polycrystalline
materials. The best fitted values... | 0204601v1 |
2002-08-09 | Quasi-one-dimensional superconductivity above 300 K and quantum phase slips in individual carbon nanotubes | A great number of the existing data for electrical transport, the Altshuler
Aronov Spivak and Aharonov Bohm effects, as well as the tunneling spectra of
individual carbon nanotubes can be well explained by theories of the quantum
phase slips in quasi-one-dimensional superconductors. The existing data
consistently sugge... | 0208198v4 |
2002-08-13 | Characterization of one-dimensional quantum channels in InAs/AlSb | We report the magnetoresistance characteristics of one-dimensional electrons
confined in a single InAs quantum well sandwiched between AlSb barriers. As a
result of a novel nanofabrication scheme that utilizes a 3nm-shallow wet
chemical etching to define the electrostatic lateral confinement, the system is
found to pos... | 0208265v1 |
2002-08-27 | Anomalous Hall Effect of Calcium-doped Lanthanum Cobaltite Films | The Hall resistivity, magnetoresistance, and magnetization of
La_{1-x}Ca_{x}CoO_{3} epitaxial films with x between 0.25 and 0.4 grown on
lanthanum aluminate were measured in fields up to 7 T. The x=1/3 film, shows a
reentrant metal insulator transition. Below 100 K, the x=1/3 and 0.4 films have
significant coercivity w... | 0208530v1 |
2003-01-24 | Semiconductive and Photoconductive Properties of the Single Molecule Magnets Mn$_{12}$-Acetate and Fe$_8$Br$_8$ | Resistivity measurements are reported for single crystals of
Mn$_{12}$-Acetate and Fe$_8$Br$_8$. Both materials exhibit a
semiconductor-like, thermally activated behavior over the 200-300 K range. The
activation energy, $E_a$, obtained for Mn$_{12}$-Acetate was 0.37 $\pm$ 0.05
eV, which is to be contrasted with the val... | 0301497v1 |
2003-02-12 | Avoided Antiferromagnetic Order and Quantum Critical Point in CeCoIn$_5$ | We measured specific heat and resistivity of heavy fermion CeCoIn5 between
the superconducting critical field $H_{c2} = 5 T$ and 9 T, with field in the
[001] direction, and at temperatures down to 50mK. At 5T the data show Non
Fermi Liquid behavior down to the lowest temperatures. At field above 8T the
data exhibit cro... | 0302226v1 |
2003-02-21 | Anomalous Hall Effect and Magnetoresistance of SrFe1-xCoxO3-d | Transport and magnetic studies on polycrystalline samples of SrFe1-xCoxO3-d
have been carried out to investigate the relationship between the magnetic
structure and the anomalous Hall resistivity rH. The hysteretic behavior of the
magnetization observed in the measurements with varying temperature T up and
then down af... | 0302436v1 |
2003-02-24 | Spin-wave scattering at low temperatures in manganite films | The temperature $T$ and magnetic field $H$ dependence of the resistivity
$\rho$ has been measured for La$_{0.8-y}$Sr$_{0.2}$MnO$_{3}$ (y=0 and 0.128)
films grown on (100) SrTiO$_{3}$ substrates. The low-temperature $\rho$ in the
ferromagnetic metallic region follows well $\rho (H,T)=\rho
_{0}(H)+A(H)\omega_{s}/\sinh (\... | 0302486v1 |
2003-04-07 | Thickness dependence of the properties of epitaxial MgB2 thin films grown by hybrid physical-chemical vapor deposition | We have studied the effect of deposition rate and layer thickness on the
properties of epitaxial MgB2 thin films grown by hybrid physical-chemical vapor
deposition on 4H-SiC substrates. The MgB2 film deposition rate depends linearly
on the concentration of B2H6 in the inlet gas mixture. We found that the
superconductin... | 0304164v1 |
2003-06-05 | Variable-range-hopping conductivity of half-doped bilayer manganite LaSr$_{2}$Mn$_{2}$O$_{7}$ | We report measurements of in-plane $\rho_{ab}$ and out-of-plane $\rho_{c}$
resistivities on a single crystal of the half-doped bilayer manganite
LaSr$_{2}$Mn$_{2}$O$_{7}$. In the temperature $T$ range 220 to 300 K, the
resistive anisotropy $\rho_{c}/\rho_{ab}=A+B/T$ ($A$ and $B$ constants), which
provides evidence for ... | 0306133v1 |
2003-06-11 | Enhanced electrical resistivity before Néel order in the metals, RCuAs$_2$ (R= Sm, Gd, Tb and Dy | We report an unusual temperature (T) dependent electrical resistivity($\rho$)
behavior in a class of ternary intermetallic compounds of the type RCuAs$_2$
(R= Rare-earths). For some rare-earths (Sm, Gd, Tb and Dy) with negligible
4f-hybridization, there is a pronounced minimum in $\rho$(T) far above
respective N\'eel t... | 0306266v1 |
2003-07-14 | Interplay between disorder, quantum and thermal fluctuations in ferromagnetic alloys: The case of UCu2Si(2-x)Ge(x) | We consider, theoretically and experimentally, the effects of structural
disorder, quantum and thermal fluctuations in the magnetic and transport
properties of certain ferromagnetic alloys.We study the particular case of
UCu2Si(2-x)Ge(x). The low temperature resistivity, rho(T,x), exhibits Fermi
liquid (FL) behavior as... | 0307328v2 |
2003-10-20 | Studies of Current-Driven Excitations in Co/Cu/Co Trilayer Nanopillars | We measure the dynamic resistance of a Co/Cu/Co trilayer nanopillar at varied
magnetic field $H$ and current $I$. The resistance displays the usual behavior,
almost symmetric in $H$, both when magnetization switching is hysteretic at
small $I,H$, and reversible at larger $I,H$. We show differences in the $I,H$
magnetiz... | 0310472v1 |
2003-11-17 | The Normal State Resistivity of Grain Boundaries in YBa2Cu3O7-delta | Using an optimized bridge geometry we have been able to make accurate
measurements of the properties of YBa2Cu3O7-delta grain boundaries above Tc.
The results show a strong dependence of the change of resistance with
temperature on grain boundary angle. Analysis of our results in the context of
band-bending allows us t... | 0311386v1 |
2004-02-09 | Molecular electronics exploiting sharp structure in the electrode density-of-states. Negative differential resistance and Resonant Tunneling in a poled molecular layer on Al/LiF electrodes | Density-functional calculations are used to clarify the role of an ultrathin
LiF layer on Al electrodes used in molecular electronics. The LiF layer creates
a sharp density of states (DOS), as in a scanning-tunneling microscope (STM)
tip. The sharp DOS, coupled with the DOS of the molecule leads to negative
differentia... | 0402257v1 |
2004-05-06 | The antiferromagnetic transition of UPd2Al3 break-junctions: A new realization of N-shaped current-voltage characteristics | We have investigated metallic break junctions of the heavy-fermion compound
UPd2Al3 at low temperatures between 0.1K and 9K and in magnetic fields up to
8T. Both the current-voltage I(V) characteristics and the dV/dI (V) spectra
clearly showed the superconducting ($T_{\rm c}\simeq$ 1.8K) as well as the
antiferromagneti... | 0405118v1 |
2004-05-11 | Weak links and phase slip centers in superconducting MgB2 wires | MgB2 superconducting wires were produced by the Mg diffusion method. Scanning
electron microscopy (SEM), optical microscopy, dispersive x-ray analysis (EDS)
and XRD diffraction were used to study the physical structure and content of
the wires. Magnetic properties (Tcm, Hc1, Hc2, Jc by the Bean model) were
obtained wit... | 0405219v1 |
2004-05-27 | Magnetic, electrical resistivity, heat-capacity and thermopower anomalies in CeCuAs2 | The results of magnetic susceptibility, electrical resistivity ($\rho$),
heat-capacity (C) and thermopower (S) measurements on CeCuAs2, forming in
ZrCuSi2-type tetragonal structure, are reported. Our investigations reveal that
Ce is trivalent and there is no clear evidence for long range magnetic ordering
down to 45 mK... | 0405638v1 |
2004-06-24 | On Electron Transport in ZrB12, ZrB2 and MgB2 | We report on measurements of the temperature dependence of resistivity,
$\rho(T)$, for single crystal samples of ZrB$_{12}$, ZrB$_{2}$ and
polycrystalline samples of MgB$_{2}$. It is shown that cluster compound
ZrB$_{12}$ behaves like a simple metal in the normal state, with a typical
Bloch -- Gr\"uneisen $\rho(T)$ dep... | 0406615v1 |
2004-07-07 | Kondo Behavior of U in CaB$_6$ | Replacing U for Ca in semiconducting CaB$_6$ at the few at.% level induces
metallic behaviour and Kondo-type phenomena at low temperatures, a rather
unusual feature for U impurities in metallic hosts. For
Ca$_{0.992}$U$_{0.008}$B$_6$, the resistance minimum occurs at $T$ = 17 K. The
subsequent characteristic logarithmi... | 0407158v1 |
2004-08-11 | Conductivity, weak ferromagnetism and charge instability in $α-MnS$ single crystal | The temperature dependence of resistivity, magnetization and electron-spin
resonance of the $\alpha- MnS $ single crystal were measured in temperature
range of $5 K < T < 550 K$. Magnetization hysteresis in applied magnetic field
up to 0.7 T at $T=5 K, 77 K, 300 K$, irreversible temperature behavior of
magnetization an... | 0408232v1 |
2004-08-26 | Deviations from plastic barriers in Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ thin films | Resistive transitions of an epitaxial Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ thin
film were measured in various magnetic fields ($H\parallel c$), ranging from 0
to 22.0 T. Rounded curvatures of low resistivity tails are observed in
Arrhenius plot and considered to relate to deviations from plastic barriers. In
order to cha... | 0408555v2 |
2004-08-27 | Examination of the c-axis resistivity of Bi_{2}Sr_{2-x}La_xCuO_{6+δ} in magnetic fields up to 58 T | We measure the magnetic-field dependence of the c-axis resistivity,
\rho_c(H), in a series of Bi_{2}Sr_{2-x}La_xCuO_{6+\delta} (BSLCO) single
crystals for a wide range of doping using pulsed magnetic fields up to 58 T.
The behavior of \rho_c(H) is examined in light of the recent determination of
the upper critical fiel... | 0408603v1 |
2004-10-06 | Ballistic resistivity in aluminum nanocontacts | One of the major industrial challenges is to profit from some fascinating
physical features present at the nanoscale. The production of dissipationless
nanoswitches (or nanocontacts) is one of such attractive applications.
Nevertheless, the lack of knowledge of the real efficiency of electronic
ballistic/non dissipativ... | 0410138v1 |
2004-12-01 | Magnetoresistive Effects in Ferromagnet-Superconductor Multilayers | We consider a nanoscale system consisting of Manganite-ferromagnet and
Cuprate-superconductor multilayers in a spin valve configuration. The
magnetization of the bottom Manganite-ferromagnet is pinned by a
Manganite-antiferromagnet. The magnetization of the top Manganite-ferromagnet
is coupled to the bottom one via ind... | 0412005v1 |
2004-12-12 | Effect of oxygen content on the transport properties and magnetoresistance in [Ca$_{2}$CoO$_{3-δ}$]$_{0.62}$[CoO$_{2}$] single crystals | Transport property is investigated in
[Ca$_{2}$CoO$_{3-\delta}$]$_{0.62}$[CoO$_{2}$] single crystals obtained by
varying annealing conditions. The $\rho_{ab}(T)$ exhibits a resistivity
minimum, and the temperature corresponding to this minimum increases with the
loss of oxygen content, indicative of the enhancement of ... | 0412298v1 |
2004-12-27 | Ferromagnetism and possible heavy fermion behavior in single crystals of NdOs$_4$Sb$_{12}$ | Single crystals of the filled-skutterudite compound NdOs$_4$Sb$_{12}$ have
been investigated by means of electrical resistivity, magnetization, and
specific heat measurements. The NdOs$_4$Sb$_{12}$ crystals have the
LaFe$_4$P$_{12}$-type cubic structure with a lattice parameter of 9.3 \AA.
Possible heavy-fermion behavi... | 0412713v3 |
2005-02-03 | Transverse "resistance overshoot" in a Si/SiGe two-dimensional electron gas in the quantum Hall effect regime | We investigate the peculiarities of the "overshoot" phenomena in the
transverse Hall resistance R_{xy} in Si/SiGe. Near the low magnetic field end
of the quantum Hall effect plateaus, when the filling factor \nu approaches an
integer i, R_{xy} overshoots the normal plateau value h/ie^2. However, if
magnetic field B inc... | 0502094v1 |
2005-03-03 | Transport properties of diluted magnetic semiconductors: Dynamical mean field theory and Boltzmann theory | The transport properties of diluted magnetic semiconductors (DMS) are
calculated using dynamical mean field theory (DMFT) and Boltzmann transport
theory. Within DMFT we study the density of states and the dc-resistivity,
which are strongly parameter dependent such as temperature, doping, density of
the carriers, and th... | 0503077v1 |
2005-04-22 | Blue light-emitting diode based on ZnO | A near-band-edge bluish electroluminescence (EL) band centered at around 440
nm was observed from ZnO p-i-n homojunction diodes through a semi-transparent
electrode deposited on the p-type ZnO top layer. The EL peak energy coincided
with the photoluminescence peak energy of an equivalent p-type ZnO layer,
indicating th... | 0504587v1 |
2005-05-17 | Transport properties of moderately disordered UCu$_4$Pd | We present a detailed study on the (magneto)transport properties of as-cast
and heat treated material UCu$_4$Pd. We find a pronounced sample dependence of
the resistivity $\rho$ of as-cast samples, and reproduce the annealing
dependence of $\rho$. In our study of the Hall effect we determine a metallic
carrier density ... | 0505418v1 |
2005-07-02 | Drastic ground state changes induced by Ni substitution in NaxCoO2 | We report on the effect of Ni substitution at the Co site on the physical
properties of NaxCoO2 system by investigating the series NaxCo1-yNiyO2 (x=0.75,
0<y<0.15). An upturn in the resistivity is observed in all Ni substituted
samples as the temperature is lowered, suggestive of the occurrence of a
Metal-Insulator Tra... | 0507045v1 |
2005-08-19 | Determination of the intrinsic anomalous Hall effect of SrRuO$_3$ | The anomalous Hall effect (AHE) of epitaxial SrRuO$_3$ films with varying
lattice parameters is investigated, and analyzed according to the Berry-phase
scenario. SrRuO$_3$ thin films were deposited on SrTiO$_3$ substrates directly,
or using intermediate buffer layers, in order to finely control the epitaxial
strain. Th... | 0508443v1 |
2005-09-05 | Magnetic and electronic transport percolation in epitaxial GeMn films | Electronic transport and magnetic properties of Ge1-xMnx/Ge(100) films are
investigated as a function of Mn dilution. Depending on x, characteristic
temperatures separate different regimes in both properties. Resistivity
exhibits an insulator-like behavior in the whole temperature range and, below
about 80 K, two disti... | 0509111v1 |
2005-10-07 | Size Dependent Breakdown of Superconductivity in Ultranarrow Nanowires | Below a certain temperature Tc (typically cryogenic), some materials lose
their electric resistance R entering a superconducting state. Folowing the
general trend toward a large scale integration of a greater number of
electronic components, it is desirable to use superconducting elements in order
to minimize heat diss... | 0510181v1 |
2005-10-07 | Evidence of ratchet effect in nanowires of a conducting polymer | Ratchet effect, observed in many systems starting from living organism to
artificially designed device, is a manifestation of motion in asymmetric
potential. Here we report results of a conductivity study of Polypyrrole
nanowires, which have been prepared by a simple method to generate a variation
of doping concentrati... | 0510188v1 |
2005-10-11 | Highly oriented VO2 thin films prepared by sol-gel deposition method | Highly oriented VO2 thin films were grown on sapphire substrates by the
sol-gel method that includes a low pressure annealing in an oxygen atmosphere.
This reduction process effectively promotes the formation of the VO2 phase over
a relatively wide range of pressures below 100 mTorr and temperatures above
400oC. X-ray ... | 0510267v2 |
2005-11-10 | Thermoelectric properties of the layered Pd oxide R_2PdO_4 (R = La, Nd, Sm and Gd) | We prepared polycrystalline samples of R$_2$PdO$_4$ (R = La, Nd, Sm and Gd)
using a NaCl-flux technique. The measured resistivity is of the order of
10$^3-10^4$ $\Omega$cm at room temperature, which is two orders of magnitude
smaller than the values reported so far. We further studied the substitution
effects of Ce for... | 0511245v1 |
2005-11-10 | Anderson localization in carbon nanotubes: defect density and temperature effects | The role of irradiation induced defects and temperature in the conducting
properties of single-walled (10,10) carbon nanotubes has been analyzed by means
of a first-principles approach. We find that di-vacancies modify strongly the
energy dependence of the differential conductance, reducing also the number of
contribut... | 0511265v1 |
2005-11-17 | Electrical Switching in Metallic Carbon Nanotubes | We present first-principles calculations of quantum transport which show that
the resistance of metallic carbon nanotubes can be changed dramatically with
homogeneous transverse electric fields if the nanotubes have impurities or
defects. The change of the resistance is predicted to range over more than two
orders of m... | 0511447v1 |
2005-11-28 | Laser microscopy of tunneling magnetoresistance in manganite grain-boundary junctions | Using low-temperature scanning laser microscopy we directly image electric
transport in a magnetoresistive element, a manganite thin film intersected by a
grain boundary (GB). Imaging at variable temperature allows reconstruction and
comparison of the local resistance vs temperature for both, the manganite film
and the... | 0511662v1 |
2006-03-16 | Coordinate transformation in the model of long Josephson junctions: geometrically equivalent Josephson junctions | The transition from the model of a long Josephson junction of variable width
to the model of a junction with a coordinate-dependent Josephson current
amplitude is effected through a coordinate transformation. This establishes the
correspondence between the classes of Josephson junctions of variable width and
quasi-one-... | 0603439v1 |
2006-03-28 | Depolarizing-Field Effect in Strained Nanoscale Ferroelectric Capacitors and Tunnel Junctions | The influence of depolarizing field on the magnitude and stability of a
uniform polarization in ferroelectric capacitors and tunnel junctions is
studied using a nonlinear thermodynamic theory. It is predicted that, in
heterostructures involving strained epitaxial films and metal electrodes, the
homogeneous polarization... | 0603762v2 |
2006-03-31 | Mechanism and Scalability in Resistive Switching of Metal-Pr0.7Ca0.3MnO3 Interface | The polarity-dependent resistive-switching across metal-Pr0.7Ca0.3MnO3
interfaces is investigated. The data suggest that shallow defects in the
interface dominate the switching. Their density and fluctuation, therefore,
will ultimately limit the device size. While the defects generated/annihilated
by the pulses and the... | 0603832v1 |
2006-04-12 | Influence of Domain Wall on Magnetocaloric Effect in GdPt$_{2}$ | The resistivity, magnetoresistance and in-field heat capacity measurements
were performed on GdPt$_{2}$ intermetallic compound. The magnetocaloric
parameters $\Delta T_{ad}$ and $-\Delta S$ were derived from the in-field heat
capacity data. Comparison has been made between the magnetocaloric effect
$-\Delta S$ and diff... | 0604297v1 |
2006-06-08 | Weak localization correction to the anomalous Hall effect in polycrystalline Fe films | In situ transport measurements have been made on ultrathin ($<$100 {\AA}
thick) polycrystalline Fe films as a function of temperature and magnetic field
for a wide range of disorder strengths. For sheet resistances $R_{xx}$ less
than $\sim 3k\Omega$, we find a logarithmic temperature dependence of the
anomalous Hall co... | 0606215v2 |
2006-07-24 | Magnetoresistance in Thin Permalloy Film (10nm-thick and 30-200nm-wide) Nanocontacts Fabricated by e-Beam Lithography | In this paper we show spin dependent transport experiments in
nanoconstrictions ranging from 30 to 200nm. These nanoconstrictions were
fabricated combining electron beam lithography and thin film deposition
techniques. Two types of geometries have been fabricated and investigated. We
compare the experimental results wi... | 0607608v1 |
2006-07-28 | Magnetic hysteresis in the microwave surface resistance of Nb samples in the critical state | We discuss the hysteretic behavior of the field-induced variations of the
microwave surface resistance in superconductors in the critical state.
Measurements have been performed in a bulk sample of Nb and a powdered one at
different values of the temperature. We discuss a model, based on the Coffey
and Clem theory, in ... | 0607754v1 |
2006-09-25 | Doping Dependence of Polaron Hopping Energies in La(1-x)Ca(x)MnO(3) (0<= x<= 0.15) | Measurements of the low-frequency (f<= 100 kHz) permittivity at T<= 160 K and
dc resistivity (T<= 430 K) are reported for La(1-x)Ca(x)MnO(3) (0<= x<= 0.15).
Static dielectric constants are determined from the low-T limiting behavior of
the permittivity. The estimated polarizability for bound holes ~ 10^{-22}
cm^{-3} im... | 0609634v1 |
2006-10-10 | Spin-polarized transport in ferromagnetic multilayered semiconductor nanostructures | The occurrence of inhomogeneous spin-density distribution in multilayered
ferromagnetic diluted magnetic semiconductor nanostructures leads to strong
dependence of the spin-polarized transport properties on these systems. The
spin-dependent mobility, conductivity and resistivity in
(Ga,Mn)As/GaAs,(Ga,Mn)N/GaN, and (Si,... | 0610275v1 |
2006-10-12 | Domain wall magnetoresistance in a nanopatterned La(2/3)Sr(1/3)MnO3 track | We have measured the contribution of magnetic domain walls (DWs) to the
electric resistance in epitaxial manganite films patterned by electron-beam
lithography into a track containing a set of notches. We find a DW
resistance-area (RA) product of ~2.5 10^(-13) Ohm/m^2 at low temperature and
bias, which is several order... | 0610338v1 |
2006-10-25 | Origin of negative differential resistance in molecular junctions of Rose Bengal | Negative differential resistance (NDR) is tuned at junctions of
electronically different dimer and trimer of Rose Bengal on an atomic flat gold
(111) surface. Isolated molecule did not show any NDR. But it was induced to
show double NDR with large peak to valley ratio (1.8~3.1) in room temperature
via charging its neig... | 0610683v1 |
2006-11-13 | Weak antilocalization in epitaxial graphene: evidence for chiral electrons | Transport in ultrathin graphite grown on silicon carbide is dominated by the
electron-doped epitaxial layer at the interface. Weak anti-localization in 2D
samples manifests itself as a broad cusp-like depression in the longitudinal
resistance for magnetic fields 10 mT$< B <$ 5 T. An extremely sharp
weak-localization re... | 0611339v2 |
2006-12-19 | Semiconductors between spin-polarized source and drain | Injecting spins into a semiconductor channel and transforming the spin
information into a significant electrical output signal is a long standing
problem in spintronics. Actually, this is the prerequisite of several concepts
of spin transistor. In this tutorial article, we discuss the general problem of
spin transport ... | 0612495v1 |
2007-01-17 | Anomalous Hall effect in anatase Ti1-xCoxO2 at low temperature regime | Anomalous Hall effect (AHE) of a ferromagnetic semiconductor anatase \cotio
thin film is studied from 10K to 300K. Magnetic field dependence of anomalous
Hall resistance is coincident with that of magnetization, while the anomalous
Hall resistance decreases at low temperature in spite of nearly
temperature-independent ... | 0701395v2 |
2007-02-17 | Room-Temperature Quantum Hall Effect in Graphene | The quantum Hall effect (QHE), one example of a quantum phenomenon that occur
on a truly macroscopic scale, has been attracting intense interest since its
discovery in 1980 and has helped elucidate many important aspects of quantum
physics. It has also led to the establishment of a new metrological standard,
the resist... | 0702408v1 |
2007-02-20 | Anomalous electric conductions in KSbO3-type metallic rhenium oxides | Single crystals of KSbO3-type rhenium oxides, La4Re6O$19, Pb6Re6O19, Sr2Re3O9
and Bi3Re3O11, were synthesized by a hydrothermal method. Their crystal
structures can be regarded as a network of three-dimensional orthogonal-dimer
lattice of edge-shared ReO6 octahedra. All of them exhibit small magnitude of
Pauli paramagn... | 0702451v1 |
2007-03-14 | Electrical transport and percolation in magnetoresistive manganite / insulating oxide composites: case of La0.7Ca0.3MnO3 / Mn3O4 | We report the results of electrical resistivity measurements carried out on
well-sintered La0.7Ca0.3MnO3 / Mn3O4 composite samples with almost constant
composition of the magnetoresistive manganite phase (La0.7Ca0.3MnO3). A
percolation threshold (fc) occurs when the La0.7Ca0.3MnO3 volume fraction is ~
0.19. The depende... | 0703367v1 |
2007-03-25 | Origin of superconductivity in nominally "undoped" T'-La$_{2-x}$Y$_{x}$CuO$_{4}$ films | We have systematically studied the transport properties of the
La$_{2-x}$Y$_{x}$CuO$_{4}$(LYCO) films of T'-phase ($0.05\leq x \leq 0.30$). In
this nominally "undoped" system, superconductivity was acquired in certain Y
doping range ($0.10\leq x \leq 0.20$). Measurements of resistivity, Hall
coefficients in normal stat... | 0703643v1 |
2005-11-13 | Non-radiating and radiating configurations driven by left-handed metamaterials | It is shown that a pair of identical emitters (e.g. wire dipole antennas) in
the focal points of a disc, made of left-handed metamaterial (a "perfect"
lens), form a non-radiating electromagnetic configuration. The emitters are fed
with voltages of equal magnitude and pi-out-of-phase. Detailed
finite-difference time-dom... | 0511113v1 |
2007-04-16 | Memory function formalism approach to electrical conductivity and optical response of dilute magnetic semiconductors | A combination of the memory function formalism and time-dependent
density-functional theory is applied to transport in dilute magnetic
semiconductors. The approach considers spin and charge disorder and
electron-electron interaction on an equal footing. Within the weak disorder
limit and using a simple parabolic approx... | 0704.2061v1 |
2007-05-15 | Magnetic, magneto-thermal and magneto-transport properties in SmMn2Si2-xGex compounds | The effect of Ge substitution for Si in SmMMn2Si2-xGex compounds has been
studied. The Sm ordering temperature is found to be much larger in the compound
with x=2, as compared to the compounds with x=0 and 1. The increase in the
intra layer Mn-Mn distance is found to be responsible for this increase. Among
these three ... | 0705.2237v1 |
2007-06-01 | Anomalous magnetoresistance of EuB$_{5.99}$C$_{0.01}$: Enhancement of magnetoresistance in systems with magnetic polarons | We present results of measurements of electrical, magnetic and thermal
properties of EuB$_{5.99}$C$_{0.01}$. The observed anomalously large negative
magnetoresistance as above, so below the Curie temperature of ferromagnetic
ordering $T_C$ is attributed to fluctuations in carbon concentration. Below
$T_C$ the carbon ri... | 0706.0091v1 |
2007-07-03 | Spatial correlation of linear and nonlinear electron transport in superconducting microwave resonator: laser scanning microscopy analysis | Spatially-resolved techniques of laser scanning microscopy (LSM) have been
used to image simultaneously the spatial variations of (i) rf current flow,
J$_RF$(x,y), of (ii) areas of resistive dissipation and (iii) the sources of
microwave nonlinearity (NL) in an operating superconducting resonator. The RF
power dependen... | 0707.0358v1 |
2007-07-04 | Resistive Switching in Cr doped SrTiO3: An X-ray Absorption Spectroscopy study | X-ray absorption spectroscopy was used to study the microscopic origin of
conductance and resistive switching in chromium doped strontium titanate
(Cr:SrTiO3). Differences in the x-ray absorption near edge spectroscopy (XANES)
at the Cr K-edge indicate that the valence of Cr changes from 3+ to 4+
underneath the anode o... | 0707.0655v1 |
2007-08-21 | Negative differential resistance of Styrene on an ideal Si[111] surface: dependence of the I-V characteristics on geometry, surface doping and shape of the STM-tip | We study the electron transport properties through a supported organic
molecule styrene (C8H8) on an ideal silicon surface Si[111] and probed by a
STM-tip. The I-V characteristics and the differential conductance of the
molecule are calculated using a self consistent approach based on non
equilibrium Green's functions.... | 0708.2834v1 |
2007-12-21 | Vibronic polarons: comments on a model for the colossal field-resistance effects in manganites | In addition to mechanisms already proposed to account for the formation in
manganites of a small-polaron superlattice above the Curie temperature Tc and
to a metallic-like sea of large polarons below Tc, we now consider other
observed colossal-resistance inducing fields, such as magnetic, electric,
photon, or strain fi... | 0712.3803v1 |
2008-03-05 | The behavior of magnetic ordering and the KOndo effect in the alloys, Ce2Rh(1-x)Co(x)Si3: Evidence from bulk studies for Fermi-surface change during magnetic ordering - QCP transformation and applicability of SDW pictur | The results of magnetic susceptibility, electrical resistivity (rho), and
heat capacity measurements as a function of temperature are reported for the
alloys, Ce2Rh(1-x)Co(x)Si3, crystallizing in an AlB2-derived hexagonal
strcture. Ce2RhSi3 exhibits antiferromagnetic ordering at 7 K. The Neel
temperature decreases grad... | 0803.0652v1 |
2008-03-09 | Upper critical field, Hall effect and magnetoresistance in the iron-based layered superconductor LaFeAsO_{0.9}F_{0.1-δ} | By using a two-step method, we successfully synthesized the iron based new
superconductor LaFeAsO_{0.9}F_{0.1-\delta}$. The resistive transition curves
under different magnetic fields were measured, leading to the determination of
the upper critical field Hc2(T) of this new superconductor. The value of Hc2 at
zero temp... | 0803.1288v2 |
2008-03-12 | Electron transport and thermoelectric properties of layered perovskite LaBaCo2O5.5 | We have investigated the systematic transport properties of the layered
112-type cobaltite LaBaCo2O5.5 by means of electrical resistivity,
magnetoresistance, electroresistance and thermoelectric measurements in various
conditions. In order to understand the complex conduction mechanism of
LaBaCo2O5.5, the transport dat... | 0803.1806v1 |
2008-03-14 | From Ohmic to Ballistic Transport in Oriented Graphite | In this work we show that for a quasi-2D system of size $\Omega$ and
thickness $t$ the resistance goes as $(2\rho/\pi t)\ln(\Omega/W)$, diverging
logarithmically with the size. Measurements in highly oriented pyrolytic
graphite (HOPG) as well as numerical simulations confirm this relation.
Furthermore, we present an ex... | 0803.2203v2 |
2008-03-19 | Theory of quantum metal to superconductor transitions in highly conducting systems | We derive the theory of the quantum (zero temperature) superconductor to
metal transition in disordered materials when the resistance of the normal
metal near criticality is small compared to the quantum of resistivity. This
can occur most readily in situations in which ``Anderson's theorem'' does not
apply. We explici... | 0803.2902v2 |
2008-03-23 | Origin of negative differential resistance in a strongly coupled single molecule-metal junction device | A new mechanism is proposed to explain the origin of negative differential
resistance (NDR) in a strongly coupled single molecule-metal junction. A
first-principles quantum transport calculation in a Fe-terpyridine linker
molecule sandwiched between a pair of gold electrodes is presented. Upon
increasing applied bias, ... | 0803.3342v1 |
2008-04-13 | Conductance of p-n-p graphene structures with 'air-bridge' top gates | We have fabricated graphene devices with a top gate separated from the
graphene layer by an air gap--a design which does not decrease the mobility of
charge carriers under the gate. This gate is used to realise p-n-p structures
where the conducting properties of chiral carriers are studied. The band
profile of the stru... | 0804.2081v3 |
2008-06-16 | Metal-insulator transition and giant anisotropic magnetoresistance in ultra thin (Ga,Mn)As | MBE-grown, 5 nm-thick annealed Ga0.95Mn0.05As films with Tc~90K demonstrate
transition from metallic to insulating state below To~10K, where sheet
resistances Rsh~h/e2 and both longitudinal Rxx and transverse Rxy components
become comparable. Below metal-insulator transition we found giant anisotropic
magnetoresistance... | 0806.2590v1 |
2008-06-28 | Theory of spin magnetohydrodynamics | We develop a phenomenological hydrodynamic theory of coherent magnetic
precession coupled to electric currents. Exchange interaction between electron
spin and collective magnetic texture produces two reciprocal effects:
spin-transfer torque on the magnetic order parameter and the Berry-phase gauge
field experienced by ... | 0806.4656v2 |
2008-07-28 | Transport anomalies across the quantum limit in semimetallic Bi$_{0.96}$Sb$_{0.04}$ | We report on a study of electronic transport in semi-metallic
Bi$_{0.96}$Sb$_{0.04}$. At zero field, the system is a very dilute Fermi liquid
displaying a T$^{2}$ resistivity with an enhanced prefactor. Quantum
oscillations in resistivity as well as in Hall, Nernst and Seebeck responses of
the system are detectable and... | 0807.4432v1 |
2008-07-30 | Ultra-Thin Silver Films obtained by Sequential Quench-Anneal Processing | We have used the two-step growth technique, quench condensing followed by an
anneal, to grow ultra thin films of silver on glass substrates. As has been
seen with semiconductor substrates this process produces a metastable
homogeneous covering of silver. By measuring the in situ resistance of the film
during growth we ... | 0807.4948v1 |
2008-08-09 | Electronic transport and specific heat of 1T- VSe2 | The results of low temperature thermoelectric power and the specific heat of
1T-VSe2 (Vanadium diselenide) have been reported along with the electrical
resistivity, and Hall coefficient of the compound. The Charge Density Wave
(CDW) transition is observed near 110K temperature in all these properties. The
Thermoelectri... | 0808.1332v2 |
2008-08-11 | Non-trivial length dependence of the conductance and negative differential resistance in atomic molecular wires | We study the electronic and transport properties of two novel molecular wires
made of atomic chains of carbon atoms (polyynes) capped with either,
benzene-thiols or pyridines. While both molecules are structurally similar, the
electrical conductance of benzene-thiol-capped chains attached to gold
electrodes is found to... | 0808.1494v2 |
2008-08-21 | Electrons and holes in Si quantum well: a room-temperature transport and drag resistance study | We investigate carrier transport in a single 22 nm-thick double-gated Si
quantum well device, which has independent contacts to electrons and holes.
Conductance, Hall density and Hall mobility are mapped in a broad double-gate
voltage window. When the gate voltage asymmetry is not too large only either
electrons or hol... | 0808.2914v1 |
2008-10-27 | Abrupt Emergence of Pressure-Induced Superconductivity of 34 K in SrFe2As2: A Resistivity Study under Pressure | We report resistivity measurement under pressure in single crystals of
SrFe_2As_2, which is one of the parent materials of Fe-based superconductors.
The structural and antiferromagnetic (AFM) transition of T_0 = 198 K at ambient
pressure is suppressed under pressure, and the ordered phase disappears above
P_c ~ 3.6-3.7... | 0810.4856v2 |
2008-12-11 | Difference of Oxide Hetero-Structure Junctions with Semiconductor Electronic Devices | Charge carrier injection performed in Pr0.7Ca0.3MnO3 (PCMO) hetero-structure
junctions exhibits stable without electric fields and dramatic changes in both
resistances and interface barriers, which are entirely different from behaviors
of semiconductor devices. Disappearance and reversion of interface barriers
suggest ... | 0812.2071v1 |
2008-12-11 | Evidence for Coexistence of Superconductivity and Magnetism in Single Crystals of Co-doped SrFe$_2$As$_2$ | In order to investigate whether magnetism and superconductivity coexist in
Co-doped SrFe$_2$As$_2$, we have prepared single crystals of
SrFe$_{2-x}$Co$_x$As$_2$, $x$ = 0 and 0.4, and characterized them via X-ray
diffraction, electrical resistivity in zero and applied field up to 9 T as well
as at ambient and applied pr... | 0812.2091v1 |
2009-01-10 | Wafer-Scale, Sub-5 nm Junction Formation by Monolayer Doping and Conventional Spike Annealing | We report the formation of sub-5 nm ultrashallow junctions in 4 inch Si
wafers enabled by the molecular monolayer doping of phosphorous and boron atoms
and the use of conventional spike annealing. The junctions are characterized by
secondary ion mass spectrometry and non-contact sheet resistance measurements.
It is fou... | 0901.1396v1 |
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