THE Pr AND OXYGEN CORRELATION IN THE GdPr123 SYSTEM

2002 ◽  
Vol 16 (25) ◽  
pp. 943-953 ◽  
Author(s):  
H. KHOSROABADI ◽  
V. DAADMEHR ◽  
M. AKHAVAN
Keyword(s):  
Electrical Resistivity ◽  
Transition Temperature ◽  
Linear Dependence ◽  
Single Phase ◽  
Hole Concentration ◽  
Resistivity Measurements ◽  
Annealing Method

We prepared single-phase polycrystalline Gd 1 - x Pr x Ba 2 Cu 3 O 7 - δ samples with x = 0, 0.10, 0.15, and 0.20. The deoxygenation process of these samples was performed by an annealing method. Electrical resistivity measurements revealed depression of the transition temperature with the increase of x and δ. We calculated the hole concentration in the CuO 2 plane for different values of x and δ. A linear dependence of transition temperature and hole concentration in the CuO 2 plane was found as a function of 2δ + x. It is proposed that a combination of the localization and filling of holes should be considered as the effective mechanisms for the appearance of the Pr anomaly in HTSCs.

scholarly journals Superconductivity in an extreme strange metal

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
D. H. Nguyen ◽  
A. Sidorenko ◽  
M. Taupin ◽  
G. Knebel ◽  
G. Lapertot ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Transition Temperature ◽  
High Temperature Superconductivity ◽  
Cooper Pairing ◽  
Complex Phase ◽  
Resistivity Measurements ◽  
Charge Localization ◽  
Electrical Resistivities ◽  
Metal State ◽  
Dynamical Charge

AbstractSome of the highest-transition-temperature superconductors across various materials classes exhibit linear-in-temperature ‘strange metal’ or ‘Planckian’ electrical resistivities in their normal state. It is thus believed by many that this behavior holds the key to unlock the secrets of high-temperature superconductivity. However, these materials typically display complex phase diagrams governed by various competing energy scales, making an unambiguous identification of the physics at play difficult. Here we use electrical resistivity measurements into the micro-Kelvin regime to discover superconductivity condensing out of an extreme strange metal state—with linear resistivity over 3.5 orders of magnitude in temperature. We propose that the Cooper pairing is mediated by the modes associated with a recently evidenced dynamical charge localization–delocalization transition, a mechanism that may well be pertinent also in other strange metal superconductors.

STUDIES ON Bi1.7Pb0.3Sr2Ca2Cu3Oy TREATED IN AIR, OXYGEN, AND ARGON GASES

1993 ◽  
Vol 07 (19) ◽  
pp. 1269-1277
Author(s):  
G. NARSINGA RAO ◽  
P. SUBHASH ◽  
D. SURESH BABU ◽  
M. GANNE
Keyword(s):  
Electrical Resistivity ◽  
Transition Temperature ◽  
Critical Current Density ◽  
Current Density ◽  
Ac Susceptibility ◽  
Resistivity Measurements ◽  
Susceptibility Data ◽  
Gaseous Environment ◽  
Grown Sample ◽  
Single Transition

We present an investigation of Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 3 O y system, treated in air, argon, and oxygen gaseous environment, by combination of XRD, SEM, electrical resistivity, and ac susceptibility measurements. XRD data of all the samples showed a presence of both 2212 and 2223 phases in the sample. As prepared sample showed a single transition temperature at 109 K in both ac susceptibility and electrical resistivity measurements. Samples treated in oxygen showed a single transition at 107 K in ac susceptibility measurements and at 104 K in resistivity measurements, whereas samples treated in argon had two transitions at 107 K and 85 K in ac susceptibility data and a single transition at 102 K in resistivity measurements. These results were explained in terms of coupling between grains. Intragrain critical current density of As grown sample was estimated.

Thermoelectric Properties of PbTe

2013 ◽  
Vol 802 ◽  
pp. 223-226 ◽  
Author(s):  
Sunti Phewphong ◽  
Tosawat Seetawan
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Room Temperature ◽  
Single Phase ◽  
Argon Atmosphere ◽  
Steady State Method ◽  
State Method ◽  
Cubic Structure ◽  
Annealing Method

The PbTe has been prepared by pressing and annealing method in argon atmosphere. The PbTe sample was obtained single phase and cubic structure. The Seebeck coefficient, the electrical resistivity, thermal conductivity measured by steady state method and evaluated dimensionless figure merit at room temperature. The values of Seebeck coefficient, the electrical resistivity, thermal conductivity and dimensionless figure merit are about -260 µV/K, 3 mΩcm, 0.5 W/m K and ~ 0.35 respectively at 420 K.

In-situ electrical-resistivity measurements in the high-voltage electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 68-69
Author(s):  
W. E. King
Keyword(s):  
Electrical Resistivity ◽  
Electron Microscope ◽  
High Voltage ◽  
Resistivity Measurements ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Wide Range ◽  
Helium Gas

A side-entry type, helium-temperature specimen stage that has the capability of in-situ electrical-resistivity measurements has been designed and developed for use in the AEI-EM7 1200-kV electron microscope at Argonne National Laboratory. The electrical-resistivity measurements complement the high-voltage electron microscope (HVEM) to yield a unique opportunity to investigate defect production in metals by electron irradiation over a wide range of defect concentrations.A flow cryostat that uses helium gas as a coolant is employed to attain and maintain any specified temperature between 10 and 300 K. The helium gas coolant eliminates the vibrations that arise from boiling liquid helium and the temperature instabilities due to alternating heat-transfer mechanisms in the two-phase temperature regime (4.215 K). Figure 1 shows a schematic view of the liquid/gaseous helium transfer system. A liquid-gas mixture can be used for fast cooldown. The cold tip of the transfer tube is inserted coincident with the tilt axis of the specimen stage, and the end of the coolant flow tube is positioned without contact within the heat exchanger of the copper specimen block (Fig. 2).

COMPUTER MODELING OF CHEMICAL EQUILIBRIUMS IN WO3–H2O SYSTEM

2017 ◽  
pp. 35-48 ◽  
Author(s):  
V.P. Bondarenko ◽  
O.O. Matviichuk
Keyword(s):  
Transition Temperature ◽  
Gas Phase ◽  
Single Phase ◽  
Reference Data ◽  
Maximum Amount ◽  
Reaction Products ◽  
Influence Of Temperature ◽  
Equilibrium Chemical ◽  
Program Data ◽  
Good Agreement

Detail investigation of equilibrium chemical reactions in WO3–H2O system using computer program FacktSage with the aim to establish influence of temperature and quantity of water on formation of compounds of H2WO4 and WO2(OH)2 as well as concomitant them compounds, evaporation products, decomposition and dissociation, that are contained in the program data base were carried out. Calculations in the temperature range from 100 to 3000 °С were carried out. The amount moles of water added to 1 mole of WO3 was varied from 0 to 27. It is found that the obtained data by the melting and evaporation temperatures of single-phase WO3 are in good agreement with the reference data and provide additionally detailed information on the composition of the gas phase. It was shown that under heating of 1 mole single-phase WO3 up to 3000 °С the predominant oxide that exist in gaseous phase is (WO3)2. Reactions of it formation from other oxides ((WO3)3 and (WO3)4) were proposed. It was established that compound H2WO4 is stable and it is decomposed on WO3 and H2O under 121 °C. Tungsten Oxide Hydrate WO2(OH)2 first appears under 400 °С and exists up to 3000 °С. Increasing quantity of Н2О in system leads to decreasing transition temperature of WO3 into both liquid and gaseous phases. It was established that adding to 1 mole WO3 26 mole H2O maximum amount (0,9044–0,9171 mole) WO2(OH)2 under temperatures 1400–1600 °С can be obtained, wherein the melting stage of WO3 is omitted. Obtained data also allowed to state that that from 121 till 400 °С WO3–Н2O the section in the О–W–H ternary system is partially quasi-binary because under these temperatures in the system only WO3 and Н2O are present. Under higher temperatures WO3–Н2O section becomes not quasi-binary since in the reaction products WO3 with Н2O except WO3 and Н2O, there are significant amounts of WO2(OH)2, (WO3)2, (WO3)3, (WO3)4 and a small amount of atoms and other compounds. Bibl. 12, Fig. 6, Tab. 5.

scholarly journals Electrical Resistivity Measurements and Soundings on Glaciers: Introductory Remarks

1967 ◽  
Vol 6 (47) ◽  
pp. 599-606 ◽  
Author(s):  
Hans Röthlisberger
Keyword(s):  
Electrical Resistivity ◽  
Resistivity Measurements ◽  
Resistivity Method

A brief description of the resistivity method is given, stressing the points which are of particular importance when working on glaciers. The literature is briefly reviewed.

The Influence of Bi2O3 on SiO2-Al2O3-B2O3-RO Glass Propertiesarts

2014 ◽  
Vol 887-888 ◽  
pp. 86-89
Author(s):  
Ying Liang Tian ◽  
Jing Zhang ◽  
Shi Bing Sun ◽  
Ji Ye Fan
Keyword(s):  
Electrical Resistivity ◽  
High Temperature ◽  
Expansion Coefficient ◽  
Bismuth Oxide ◽  
Sintering Temperature ◽  
Oxide Content ◽  
Basic Composition ◽  
Wide Range ◽  
Melt Annealing ◽  
Annealing Method

In the paper, regarded SiO2-Al2O3-B2O3-RO system as basic composition, high-temperature glass glaze was prepared successfully by using Bi2O3 in place of Al2O3, and traditional melt annealing method was adopted .The influence of Bi2O3 on expansion coefficient, sintering temperature, electrical resistivity was investigated by DIL-2008, SJY sintering imager, Keythley2410. The results show that the sintering temperature of glass glaze has a wide range, which can reach 270°C, so it is easy to sinter; with the increasing of bismuth oxide content, expansion coefficient of glass glaze gradually increases, whereas sintering temperature and electrical resistivity continuously decreases.

Effects of Ce filling fraction and Fe content on the thermoelectric properties of Co-rich CeyFexCo4−xSb12

2001 ◽  
Vol 16 (3) ◽  
pp. 837-843 ◽  
Author(s):  
Xinfeng Tang ◽  
Lidong Chen ◽  
Takashi Goto ◽  
Toshio Hirai
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Single Phase ◽  
Lattice Thermal Conductivity ◽  
Hole Concentration ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Filling Fraction ◽  
Fe Content

Single-phase filled skutterudite compounds, CeyFexCo4−xSb12 (x = 0 to 3.0, y = 0 to 0.74), were synthesized by a melting method. The effects of Fe content and Ce filling fraction on the thermoelectric properties of CeyFexCo4−xSb12 were investigated. The lattice thermal conductivity of Ce-saturated CeyFexCo4−xSb12, y being at the maximum corresponding to x, decreased with increasing Fe content (x) and reached its minimum at about x = 1.5. When x was 1.5, lattice thermal conductivity decreased with increasing Ce filling fraction till y = 0.3 and then began to increase after reaching the minimum at y = 0.3. Hole concentration and electrical conductivity of Cey Fe1.5Co2.5Sb12 decreased with increasing Ce filling fraction. The Seebeck coefficient increased with increasing Ce filling fraction. The greatest dimensionless thermoelectric figure of merit T value of 1.1 was obtained at 750 K for the composition of Ce0.28Fe1.52Co2.48Sb12.

STUDY OF THE DEPENDENCE OF HIGH Tc ON VARIOUS SINTERING TEMPERATURES FOR Bi-Pb-Sr-Ca-Cu-O SUPERCONDUCTORS

1991 ◽  
Vol 05 (24n25) ◽  
pp. 1635-1638
Author(s):  
S.M. M.R. NAQVI ◽  
A.A. QIDWAI ◽  
S.M. ZIA-UL-HAQUE ◽  
FIROZ AHMAD ◽  
S.D.H. RIZVI ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Liquid Nitrogen ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Resistivity Measurements ◽  
Zero Resistance

Bi1.7-Pb0.3-Sr2-Ca2-Cu3-Ox superconducting samples were prepared at 855°C, 862 C, 870 C, and 882 C sintering temperatures respectively. All samples were sintered for 120 hours. The samples were then quenched in liquid nitrogen. The electrical resistivity measurements showed that the samples sintered at 870° C had the best Tc. For these samples the Tc onset was around 120 K and the zero resistance was obtained at 108 K. X-ray diffraction studies showed that the samples were multiphased.

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