High pressure thermoelectric power and electrical resistance measurements in WS2 single crystals

1995 ◽  
Vol 27/28 (2) ◽  
pp. 163-169 ◽  
Author(s):  
Ajay Agarwal ◽  
Sudeep Goyal ◽  
Mahendra Agarwal ◽  
Sudhir Vaidya ◽  
Chokalingam Karunakaran
Keyword(s):  
High Pressure ◽  
Single Crystals ◽  
Thermoelectric Power ◽  
Electrical Resistance ◽  
Electrical Resistance Measurements

A phase transition in Ga2Se3 under high pressure

1994 ◽  
Vol 72 (9-10) ◽  
pp. 681-682 ◽  
Author(s):  
K. V. Savchenko ◽  
V. V. Shchennikov
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Thermoelectric Power ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Vickers Microhardness ◽  
Zinc Blende ◽  
Stockbarger Method ◽  
Zinc Blende Structure ◽  
Semiconductor Type

Ga2Se3 crystals with an excess of Se were grown by the Bridgman–Stockbarger method and had a defect zinc blende structure with a0 = 5.42 Å [Formula: see text] (1 Å = 10−10 m). At room temperature the resistivity was equal to (4.5 ± 1.5) × 1011 Ω cm, the thermoelectric power was (−1.1 ± 0.1) mV K−1 and the Vickers microhardness was (357 ± 9) kg mm−2. The gamma-induced conductivity was measured in the gamma-emitting power range of 3–340 rad s−1. Pressure dependencies of electrical resistance and thermoelectric power at room temperature allowed us to determine a phase transition of the semiconductor–semiconductor type at 14.2 GPa.

Effect of High Pressure on the Thermoelectric Power and Electrical Resistance of Aluminum and Gold

1968 ◽  
Vol 165 (3) ◽  
pp. 853-864 ◽  
Author(s):  
R. R. Bourassa ◽  
D. Lazarus ◽  
D. A. Blackburn
Keyword(s):  
High Pressure ◽  
Thermoelectric Power ◽  
Electrical Resistance

High pressure thermopower and electrical resistance measurements in CeSn3, CeAl3, CeAl2 and CeIn3

1983 ◽  
Vol 46 (7) ◽  
pp. 549-551 ◽  
Author(s):  
V. Vijayakumar ◽  
S.N. Vaidya ◽  
E.V. Sampathkumaran ◽  
R. Vijayaraghavan
Keyword(s):  
High Pressure ◽  
Electrical Resistance ◽  
Electrical Resistance Measurements

Low temperature amorphization and superconductivity in FeSe single crystals at high pressures

2010 ◽  
Vol 25 (2) ◽  
pp. 396-400 ◽  
Author(s):  
Andrew K. Stemshorn ◽  
Georgiy Tsoi ◽  
Yogesh K. Vohra ◽  
Stanislav Sinogeiken ◽  
Phillip M. Wu ◽  
...  
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Single Crystals ◽  
Amorphous Phase ◽  
Tetragonal Phase ◽  
Electrical Resistance ◽  
Low Temperatures ◽  
High Pressures ◽  
X Ray Diffraction ◽  
X Ray

In this study, we report low temperature x-ray diffraction studies combined with electrical resistance measurements on single crystals of iron-based layered superconductor FeSe to a temperature of 10 K and a pressure of 44 GPa. The low temperature high pressure x-ray diffraction studies were performed using a synchrotron source and superconductivity at high pressure was studied using designer diamond anvils. At ambient temperature, the FeSe sample shows a phase transformation from a PbO-type tetragonal phase to a NiAs-type hexagonal phase at 10 ± 2 GPa. On cooling, a structural distortion from a PbO-type tetragonal phase to an orthorhombic Cmma phase is observed below 100 K. At a low temperature of 10 K, compression of the orthorhombic Cmma phase results in a gradual transformation to an amorphous phase above 15 GPa. The transformation to the amorphous phase is completed by 40 GPa at 10 K. A loss of superconductivity is observed in the amorphous phase and a dramatic change in the temperature behavior of electrical resistance indicates formation of a semiconducting state at high pressures and low temperatures. The formation of the amorphous phase is attributed to a kinetic hindrance to the growth of a hexagonal NiAs phase under high pressures and low temperatures.

THE EFFECT OF THE MARTENSITIC TRANSFORMATION IN SODIUM ON THE THERMOELECTRIC POWER

1962 ◽  
Vol 40 (5) ◽  
pp. 550-556 ◽  
Author(s):  
J. Adler ◽  
S. B. Woods
Keyword(s):  
Crystal Structure ◽  
Martensitic Transformation ◽  
Thermoelectric Power ◽  
Electrical Resistance ◽  
Hexagonal Phase ◽  
Body Centered Cubic ◽  
Small Temperature ◽  
Experimental Apparatus ◽  
Electrical Resistance Measurements ◽  
Mixed Samples

When sodium is cooled, its crystal structure partially changes by martensitic transformation from body-centered cubic to close-packed hexagonal below about 40° K. Reversion does not begin until the temperature is raised above about 45° K, so there is a small temperature range in which sodium may consist of either pure body-centered cubic or mixed phases. Using results obtained by Dugdale and Gugan, it is possible to estimate the amount of hexagonal phase present in the mixed samples from electrical resistance measurements. We have measured the thermoelectric power at 43° K for specimens of body-centered cubic sodium and for partially transformed sodium whose composition was thus known. From these measurements the thermoelectric power of pure hexagonal sodium is estimated to be 10% smaller than that of cubic sodium at 43° K. The distribution of the phases in the partially transformed material is represented by two different models and this result is found to be insensitive to which is used. A brief description of the experimental apparatus is given and some theoretical implications of the results are considered.

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