THE NORMAL STATE HALL EFFECT IN NdBa2-xLaxCu3O7-δ: EVIDENCE FOR HOLE LOCALIZATION BY LA DOPING

The transport properties of sintered samples of NdBa 2-x La x Cu 3 O 7-δ with 0 ≤ x ≤ 0.3 have been studied in the normal state by Hall effect measurements. The Hall coefficient, RH is positive in the normal state and increases with increasing La doping concentration over the whole temperature range from the critical temperature, Tc, up to room temperature. The results for the Hall coefficient as a function of temperature and doping concentration were analyzed within the phenomenological narrow band and Anderson models. A good agreement between models and data was obtained. As in the phenomenological narrow band model, the band widths increase with increasing doping concentration. As in the Anderson model, the Hall angle is proportional to T2 over the whole measured temperature range for all samples. The obtained results for both models supported the view that La doping introduces electronic disorder into the CuO 2 planes. The tendency towards localization is driven by electronic disorder. In addition to hole filling, the localization is another reason for the decreasing superconducting critical temperature in these samples.

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Electrical Properties of Orthorhombic Iron Disilicide

MRS Proceedings ◽

10.1557/proc-545-161 ◽

1998 ◽

Vol 545 ◽

Author(s):

Jun-Ichi Tani ◽

Hiroyasu Kido

Keyword(s):

Electrical Properties ◽

Solid Solutions ◽

Hole Concentration ◽

Band Model ◽

Measured Temperature ◽

Iron Disilicide ◽

Temperature Range ◽

Order Of Magnitude ◽

Mn Doped ◽

Two Band Model

AbstractIn order to clarify the electrical properties of Cr-doped β-FeSi2(Fe1-xCrxSi2) and Mn-doped β--FeSi2(Fel-yMnySi2), the Hall effect and electrical resistivity of Fe1-xCrxSi2(0.01 ≦ x ≦ 0.05) and Fel-yMnySi2(0.01 ≦ y ≦ 0.10) have been measured in the temperature range between 80 and 300 K. fhe solid solutions Fel-xCrxSi2and Fel-yMnySi2are p-type over the measured temperature range. The observed features of RH of these solid solutions are explained by using the two-band model with the existence of two acceptor levels. The hole concentration of Fe1-xCrxSi2at 300 K ranges from 8.9×1018cm−3for x=0.01 to 1.1×1020cm−3for x=0.05, which is one order of magnitude higher than that of Fel-yMnySi2.

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Determination of Planck Mean Absorption Coefficients for HBr, HCl, and HF

Journal of Heat Transfer ◽

10.1115/1.1416689 ◽

2001 ◽

Vol 124 (1) ◽

pp. 26-29 ◽

Cited By ~ 16

Author(s):

S. P. Fuss ◽

A. Hamins

Keyword(s):

Absorption Coefficient ◽

Narrow Band ◽

Band Model ◽

Absorption Coefficients ◽

Temperature Range ◽

Average Value ◽

Integrated Intensity ◽

Using Data ◽

Narrow Band Model

The Planck mean absorption coefficient, ap, has been calculated for HBr, HCl, and HF over a temperature range from 300 K–2300 K using data from the 1996 edition of the HITRAN molecular database. Plots of ap versus temperature showed monotonically decreasing behavior over this temperature range, with peak values at 300 K of 45.9 (atm-m)−1, 5.3 (atm-m)−1, and 1.95 (atm-m)−1 for HF, HCl, and HBr, respectively. The magnitude of these values suggests that HBr, HCl, and HF can significantly impact calculations of radiative transfer in flames containing these species. Two sets of additional calculations were performed for CO to validate the methodology used for calculation of ap for HBr, HF, and HCl. In the first approach, which employed the narrow band model RADCAL, the calculation procedure was similar to that of the present calculations. The second approach utilized tabulated values of the integrated intensity for each CO band and an average value of the Planck function within each band. Results from the three methods showed general agreement. Polynomial expressions are provided as fits to ap as a function of temperature for HBr, HCl, HF, and CO.

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Thermo-Electric Power of the Bi2Sr2Ca1-xCexCu2Oy System

Modern Physics Letters B ◽

10.1142/s0217984998000585 ◽

1998 ◽

Vol 12 (12) ◽

pp. 475-488 ◽

Cited By ~ 2

Author(s):

D. R. Sita ◽

R. Singh

Keyword(s):

Temperature Dependence ◽

Electric Power ◽

Normal State ◽

Narrow Band ◽

Theoretical Models ◽

Band Model ◽

Variable Range Hopping ◽

Thermo Electric ◽

Variable Range ◽

Narrow Band Model

The temperature dependence of thermo-electric power (TEP) of Bi 2 Sr 2 Ca 1-x Ce x Cu 2 O y samples with x upto 0.4 are reported in the temperature range 40–300 K. The normal state TEP data of the superconducting samples are discussed in view of some of the existing theoretical models in the literature, viz. two-band models, Nagaosa and Lee model and a phenomenological narrow band model. The transport in the semiconducting sample is found to be by variable-range-hopping mechanism.

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Exciton narrow band model for 7,7,8,8-tetracyanoquino-dimethane salts

Journal of the Chemical Society Faraday Transactions 2 Molecular and Chemical Physics ◽

10.1039/f29757101792 ◽

1975 ◽

Vol 71 ◽

pp. 1792

Author(s):

L. Shields

Keyword(s):

Narrow Band ◽

Band Model ◽

Narrow Band Model

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Critical constants and density dependence of the Lorenz–Lorentz coefficient for germane

Canadian Journal of Physics ◽

10.1139/p78-150 ◽

1978 ◽

Vol 56 (9) ◽

pp. 1140-1141 ◽

Cited By ~ 2

Author(s):

P. Palffy-Muhoray ◽

D. Balzarini

Keyword(s):

Critical Temperature ◽

Density Dependence ◽

Experimental Error ◽

Critical Density ◽

Coexistence Curve ◽

Index Of Refraction ◽

Density Range ◽

Temperature Range ◽

Critical Constants

The index of refraction at 6328 Å has been measured for germane in the density range 0.15 to 0.9 g/cm3. The temperature and density ranges over which measurements are made are near the coexistence curve. The coefficient in the Lorenz–Lorentz expression, [Formula: see text], is constant to within 0.5% within experimental error for the temperature range and density range studied. The coefficient is slightly higher near the critical density. The critical density is measured to be 0.503 g/cm3. The critical temperature is measured to be 38.92 °C.

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Magnetotransport Study of Electron Doping in Sr2FeMoO6

Materials Science Forum ◽

10.4028/www.scientific.net/msf.700.19 ◽

2011 ◽

Vol 700 ◽

pp. 19-22

Author(s):

Jibu Stephen ◽

Grant V. M. Williams ◽

Benjamin J. Ruck

Keyword(s):

Magnetic Fields ◽

Hall Effect ◽

Hall Coefficient ◽

Anomalous Hall Effect ◽

Small Decrease ◽

Electron Doping ◽

La Doped

We report the results from magnetotransport measurements on polycrystalline Sr2-xLaxFeMoO6 samples at magnetic fields of up to 8 T. We observe a normal as well as an anomalous Hall effect. We find that there is a small decrease in the normal Hall coefficient for La doped samples.

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LOW-TEMPERATURE NORMAL-STATE HALL EFFECT IN HIGH-TcBi2Sr2-xLaxCuO6+δ REVEALED BY 60 T MAGNETIC FIELDS

International Journal of Modern Physics B ◽

10.1142/s0217979202013845 ◽

2002 ◽

Vol 16 (20n22) ◽

pp. 3171-3174

Author(s):

F. F. BALAKIREV ◽

J. B. BETTS ◽

G. S. BOEBINGER ◽

S. ONO ◽

Y. ANDO ◽

...

Keyword(s):

Magnetic Field ◽

Low Temperature ◽

Carrier Concentration ◽

Hall Coefficient ◽

Normal State ◽

Ground State ◽

Low Temperatures ◽

Optimal Doping ◽

Underdoped Sample ◽

Additional Support

We report low-temperature Hall coefficient in the normal state of the high-Tc superconductor Bi 2 Sr 2-x La x CuO 6+δ. The Hall coefficient was measured down to 0.5 K by suppressing superconductivity with a 60 T pulsed magnetic field. The carrier concentration was varied from overdoped to underdoped regimes by partially substituting Sr with La in a set of five samples. The observed saturation of the Hall coefficient at low temperatures suggests the ability to extract the carrier concentration of each sample. The most underdoped sample exhibits a diverging Hall coefficient at low temperatures, consistent with a depletion of carriers in the insulating ground state. The Hall number exhibits a sharp peak providing additional support for the existence of a phase boundary at the optimal doping.

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