TRANSPORT PROPERTIES OF LixCu(1 − x)O

1993 ◽  
Vol 07 (03) ◽  
pp. 163-169 ◽  
Author(s):  
R. FEDUZI ◽  
F. LANZA ◽  
V. DALLACASA
Keyword(s):  
Transport Properties ◽  
Thermal Activation ◽  
Activation Mechanism ◽  
Variable Range Hopping ◽  
Disordered System ◽  
Variable Range ◽  
Hopping Mechanism ◽  
Resistivity Data

The resistivity of Li doped CuO polycrystalline samples is discussed following the variable-range hopping mechanism (VRH) form, exp ((T0/T)1/4), between 80 and 300 K. The T0 have been measured to be in the range of 107 − 108 K . In the CuO undoped system, the VRH mechanism does not fit appreciably the resistivity data in the range of temperature considered. However, when Li is introduced, this behaviour is followed, leading us to suggest that the Li doped CuO could be view as a disordered system. At higher temperatures, the thermal activation mechanism takes place.

Variable Range Hopping Resistivity in La2-xSrxCuO4 Nanoparticles Evaluated by Four Point Probe Method

2020 ◽  
Vol 860 ◽  
pp. 142-147
Author(s):  
Suci Winarsih ◽  
Faisal Budiman ◽  
Hirofumi Tanaka ◽  
Tadashi Adachi ◽  
Takayuki Goto ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Thermal Activation ◽  
Resistivity Measurement ◽  
Probe Method ◽  
Charge Carriers ◽  
High Resistivity ◽  
Variable Range Hopping ◽  
Variable Range ◽  
Hopping Model ◽  
Variable Range Hopping Model

We report the results of the resistivity measurement on La2-xSrxCuO4 nanoparticles with x = 0, 0.05, and 0.20 evaluated by the four-point probe method. The high resistivity value shows the predominance of the inter-grain part. The temperature dependence of the conductivity can be analyzed by variable range hopping model showing the charge carriers are formed by thermal activation. There is no superconducting behavior that could be observed in La2-xSrxCuO4 nanoparticles with x = 0.05 and 0.20.

Bose-Glass Behavior in Bi2Sr2Ca1-xYxCu2O8 Crystals with Columnar Defects: Experimental Evidence for Variable-Range Hopping

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3338-3341
Author(s):  
V. Ta Phuoc ◽  
R. De Sousa ◽  
L. Ammor ◽  
J. C. Soret ◽  
A. Ruyter ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Heavy Ions ◽  
Variable Range Hopping ◽  
Variable Range ◽  
Hopping Mechanism ◽  
Columnar Defects ◽  
Show Evidence ◽  
Bose Glass ◽  
Different Doses ◽  
Glass Behavior

We report on vortex transport in Bi2Sr2Ca 1-x Y x Cu2O8 crystals irradiated at different doses of heavy ions. We show evidence of a flux-creep resistivity typical of a variable-range vortex hopping mechanism as predicted by Nelson and Vinokur.

Path to Strong Insulating Transport Properties in Bulk AlPdRe Samples

2003 ◽  
Vol 805 ◽  
Author(s):  
Ralph Rosenbaum ◽  
Yuan-Liang Zhong ◽  
Juhn-Jong Lina
Keyword(s):  
Simple Model ◽  
Magnetic Fields ◽  
Transport Properties ◽  
Electronic Transport ◽  
Power Laws ◽  
Zero Field ◽  
Variable Range Hopping ◽  
Inverse Temperature ◽  
Variable Range ◽  
Transport Measurements

ABSTRACTElectronic transport measurements have been made on bulk icosahedral Al70Pd22.5Re7.5 quasicrystal (QC's) samples, having increasingly larger resistance temperature ratios, rT = R(4.2 K)/R(292 K). Data were taken between 0.023 K to 292 K and in magnetic fields up to 17.9 T. Both the zero field resistivity and the magnetoresistance (MR) changed from metallic behavior to weakly insulating behavior to highly insulating behavior, as the resistance temperature ratios rT's of the samples were made larger. For the insulating samples, the resistivities ρ's followed simple inverse temperature power laws above 50 K going as ρ(T) = a0/Tz, where z = 1 ± 0.1.The insulating QC samples exhibited saturation behaviors of their resistivities below 2 K. Below 0.3 K, the strongly insulating QC's displayed activated variable-range hopping (VRH) laws in their conductivity; the hopping exponents y's in the VRH laws varied between 0.19 ≤ y ≤ 0.43. A simple model including conductivity contributions both from the primary insulating QC phase and from a secondary metallic phase yielded good fits to the resistivity and MR data.

Transport properties of the organic conductor (TMTSF)2BrO4: Evidence of variable-range hopping

1984 ◽  
Vol 9 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Kell Mortensen ◽  
C.S. Jacobsen ◽  
K. Bechgaard ◽  
J.M. Williams
Keyword(s):  
Transport Properties ◽  
Variable Range Hopping ◽  
Organic Conductor ◽  
Variable Range

scholarly journals Apparent Power Law Scaling of Variable Range Hopping Conduction in Carbonized Polymer Nanofibers

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Kyung Ho Kim ◽  
Samuel Lara-Avila ◽  
Hojin Kang ◽  
Hans He ◽  
Johnas Eklӧf ◽  
...  
Keyword(s):  
Experimental Data ◽  
Transport Properties ◽  
Power Law ◽  
Hopping Conduction ◽  
Universal Curve ◽  
Variable Range Hopping ◽  
Polymer Nanofibers ◽  
Variable Range ◽  
Structural Differences ◽  
Variable Range Hopping Conduction

Abstract We induce dramatic changes in the structure of conducting polymer nanofibers by carbonization at 800 °C and compare charge transport properties between carbonized and pristine nanofibers. Despite the profound structural differences, both types of systems display power law dependence of current with voltage and temperature, and all measurements can be scaled into a single universal curve. We analyze our experimental data in the framework of variable range hopping and argue that this mechanism can explain transport properties of pristine polymer nanofibers as well.

ELECTRICAL AND MAGNETO-TRANSPORT PROPERTIES OF La0.8Sr0.2MnO3

2011 ◽  
Vol 25 (28) ◽  
pp. 3825-3833
Author(s):  
S. T. SHILAN ◽  
L. S. EWE ◽  
R. ABD-SHUKOR
Keyword(s):  
Transport Properties ◽  
Sintering Temperature ◽  
Small Polaron ◽  
Variable Range Hopping ◽  
Polaron Hopping ◽  
Variable Range ◽  
Small Polaron Hopping ◽  
Paramagnetic Region ◽  
Magneto Resistance ◽  
Hopping Model

The effects of sintering temperature on the electrical and magneto-transport properties of La 0.8 Sr 0.2 MnO 3 compounds prepared by employing a chemical co-precipitation route sintered at 1120°C, 1220°C and 1320°C are reported. The X-ray powder diffraction patterns for all samples can be indexed to the rhombohedra structure with R3C space group. The insulator–metal transition temperature remained nearly constant (~291 K) for all samples. The magneto resistance (MR) values were found to decrease noticeably as the sintering temperature was increased from 1120°C to 1320°C. Above 0.3 T, the magneto resistance was influenced by To values, which indicates the bending of Mn–O–Mn bond. The resistivity data were fitted with several equations in the metallic (ferromagnetic) region. In the insulating (paramagnetic) region, the variable range hopping and small polaron hopping models were used to compute the density of states at the Fermi level, N(EF), and activation energy (Ea) of the electrons. The resistivities can be fitted well with ρ–T2 and ρ–T2.5 curves. The variable range hopping model and small polaron hopping model fitted very well at high temperature regions, indicating that small polaron hopping might be responsible for the conduction. La 0.8 Sr 0.2 MnO 3 sintered at 1220°C demonstrated the highest MR of 6.5% in 1 T magnetic field.

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