A novel approach for identifying and synthesizing highdielectric materials

1999 ◽  
Vol 14 (8) ◽  
pp. 3192-3195 ◽  
Author(s):  
J.-H. Park ◽  
J. B. Parise ◽  
P. M. Woodward ◽  
I. Lubomirsky ◽  
O. Stafsudd
Keyword(s):  
High Pressure ◽  
Molar Volume ◽  
High Pressures ◽  
Dielectric Constants ◽  
New Materials ◽  
Twofold Increase ◽  
Novel Approach ◽  
High Pressures And Temperatures ◽  
High Dielectric

Modern telecommunications require materials with high dielectric constants (κ). The number of suitable elements ultimately limits one approach to the discovery of new materials, targeting compositions with high atomic polarizabilities (α). By decreasing the molar volume of compositions with high α, however, we anticipated dramatic increases in κ and demonstrated that this approach works. The quenched high-pressure perovskite polymorph of Na2MTeO6 (M = Ti, Sn) showed a twofold increase in κ, compared to the ilmenite form. This result suggested the highest values of κ occur for compositions with high α, which form quenchable compounds at high pressures and temperatures.

scholarly journals The thermal conductivity of the Earth's core and implications for its thermal and compositional evolution

2020 ◽  
Author(s):  
Kenji Ohta ◽  
Kei Hirose
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Thermal History ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
Iron Alloys ◽  
Compositional Evolution ◽  
The Earth ◽  
Diamond Anvil ◽  
High Pressures And Temperatures

Abstract Precise determinations of the thermal conductivity of iron alloys at high pressures and temperatures are essential for understanding the thermal history and dynamics of the metallic cores of the Earth. We review relevant high-pressure experiments using a diamond-anvil cell and discuss implications of high core conductivity for its thermal and compositional evolution.

scholarly journals The Takahashi–Bassett Era of Mineral Physics at Rochester in the 1960s

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 344
Author(s):  
William A. Bassett
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Faculty Position ◽  
Mineral Physics ◽  
High Pressure High Temperature ◽  
High Pressures And Temperatures ◽  
The 1960S ◽  
Talented Students ◽  
The University

The late Taro Takahashi earned a particularly well-deserved reputation for his research at Lamont Geological Observatory on carbon dioxide and its transfer between the atmosphere and the oceans. However, his accomplishments in Mineral Physics, the field embracing the high-pressure–high-temperature properties of materials, has received less attention in spite of his major contributions to this emerging field focused on the interiors of Earth and other planets. In 1963, I was thrilled when he was offered a faculty position in the Geology Department at the University of Rochester, where I had recently joined the faculty. Taro and I worked together for the next 10 years with our talented students exploring the blossoming field just becoming known as Mineral Physics, the name introduced by Orson Anderson and Ed Schreiber, who were also engaged in measuring physical properties at high pressures and temperatures. While their specialty was ultrasonic velocities in minerals subjected to high pressures and temperatures, ours was the determination of crystal structures, compressibilities, and densities of such minerals as iron, its alloys, and silicate minerals, especially those synthesized at high-pressure, such as silicates with the spinel structure. These were materials expected to be found in the Earth’s interior and could therefore provide background for the interpretation of geophysical observations.

scholarly journals My Career as a Mineral Physicist at Stony Brook: 1976–2019

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 761
Author(s):  
Robert Cooper Liebermann
Keyword(s):  
High Pressure ◽  
Graduate Students ◽  
High Pressures ◽  
Physics Institute ◽  
Faculty Position ◽  
Mineral Physics ◽  
Princeton University ◽  
Structural Analogues ◽  
High Pressures And Temperatures ◽  
The U.S

In 1976, I took up a faculty position in the Department of Geosciences of Stony Brook University. Over the next half century, in collaboration with graduate students from the U.S., China and Russia and postdoctoral colleagues from Australia, France and Japan, we pursued studies of the elastic properties of minerals (and their structural analogues) at high pressures and temperatures. In the 1980s, together with Donald Weidner, we established the Stony Brook High Pressure Laboratory and the Mineral Physics Institute. In 1991, in collaboration with Alexandra Navrotsky at Princeton University and Charles Prewitt at the Geophysical Laboratory, we founded the NSF Science and Technology Center for High Pressure Research.

scholarly journals Hochdrucksynthese quaternärer Chalkogenidhalogenide AB2X3Y (A = Cu, Ag; B = In; X = S, Se, Te; Y = Cl, Br, I)/High Pressure Synthesis of Quaternary Chalcogenide Halogenides AB2X3Y (A = Cu, Ag; B = In; X = S, Se, Te; Y = Cl, Br, I)

1983 ◽  
Vol 38 (2) ◽  
pp. 155-160 ◽  
Author(s):  
Klaus-Jürgen Range ◽  
Heinz-Joachim Hübner
Keyword(s):  
High Pressure ◽  
Crystal Structures ◽  
Spinel Structure ◽  
High Pressures ◽  
Reaction Pathways ◽  
High Pressure Synthesis ◽  
Quaternary Compounds ◽  
Pressure Synthesis ◽  
High Pressures And Temperatures

Abstract Quaternary compounds AB2X3Y (A = Cu, Ag; B = In; X = S, Se, Te; Y = Cl, Br, I) could be synthesized at high pressures and temperatures. The crystal structures found are defect-zincblende (AgIn2Se3I, AgIn2Te3l, CuIn2Se3Br, CuIn2Se3I, CuIn2Te3Cl, CuIn2Te3Br, CuInTe3I), spinel (AgIn2S3Cl, AgIn2S3Br, AgIn2Se3Cl, AgIn2Se3Br, AgIn2Se3l) and defect-rocksalt (AgIn2Te3Cl, AgIn2Te3Br). A second form of CuIn2Se3l is intermediate between the zincblende and spinel structure. A survey of the different reaction pathways of AB-B2X3 mixtures at high pressures and temperatures is given.

High Pressure Carbon Behavior Induced from Carbide Hugoniots

1997 ◽  
Vol 499 ◽  
Author(s):  
T. Sekine ◽  
E. Takazawa ◽  
T. Kobayashi
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Molar Volume ◽  
Partial Molar Volume ◽  
High Pressures ◽  
Diamond Structure ◽  
Structural Variations ◽  
Diamond Phase ◽  
Type Carbide ◽  
Diamond Type

ABSTRACTInvestigations of Hugoniots the diamond-type carbides(various SiC) and NaCl-type carbides such as TiC give some insights into the high-pressure carbon behaviors. The experimental results of phase transitions of a-SiC and β-SiC, together with those of diamond-structure Si, imply that the candidate as post-diamond phase has sixfold coordination and that a possible transition pressure is about 1–2 TPa. The NaCl-type carbide Hugoniots indicate that sixfold coordinated C is very stable at high pressures. The partial molar volume of carbon in the NaCl-type carbides ranges between 1.4 to 2.6 cnvVg-atom C at 1 atm and reaches about 2.8 cm3/g-atom C at 100 GPa. Taking into account structural variations of the corresponding metals, the volume of the sixfold coordinated C is estimated to be 1.7 cm3/g-atom C, about half of that of diamond, and the post-diamond phase appears to be extremely hard.

Dimerization of Carboxylic Acids in Solution up to High Pressures and Temperatures. 1. Pivalic Acid

1987 ◽  
Vol 42 (2) ◽  
pp. 187-196
Author(s):  
E. M. Borschel ◽  
M. Buback
Keyword(s):  
Hydrogen Bond ◽  
High Pressure ◽  
Ir Spectroscopy ◽  
Quantitative Measurement ◽  
High Pressures ◽  
Pressure Effect ◽  
Pivalic Acid ◽  
Dilute Solution ◽  
Hydrogen Bond Strength ◽  
High Pressures And Temperatures

Pivalic acid in dilute solution of n-heptane and of CCl4 is studied via IR spectroscopy in the region of the C = O and O - H stretching fundamentals up to pressures of 2 kbar and temperatures of 175 °C. Lambert-Beer's law is shown to be valid for the C = O modes of the acid monomer and of the hydrogen-bonded cyclic dimer, which enables the quantitative measurement of the dimerization equilibrium as a function of pressure and temperature. Increasing pressure favours the dimerization in n-heptane to a larger extent than in CCl4 solution. In both solvents this pressure effect increases with temperature. The hydrogen bond strength within the dimer species is slightly reduced toward high pressure. The data on the temperature dependence of the dimerization volume and on the pressure dependence of the dimerization enthalpy are compared with direct information on both species as derived from their O - H fundamental modes.

Die Kinetik des Zerfalls von tert. Butylperoxypivalat bei hohen Drücken und Temperaturen / The Kinetics of the Decomposition of tert.Butylperoxypivalate up to High Pressures and Temperatures

1981 ◽  
Vol 36 (12) ◽  
pp. 1371-1377 ◽  
Author(s):  
M. Buback ◽  
H. Lendle
Keyword(s):  
Activation Energy ◽  
High Pressure ◽  
High Pressures ◽  
Activation Volume ◽  
Rate Law ◽  
First Order ◽  
Order Rate ◽  
High Pressures And Temperatures ◽  
Kinetics Of

AbstractThe decomposition of tert. butylperoxypivalate dissolved in n-heptane has been measured ir-spectroscopically in optical high-pressure cells up to 2000 bar at temperatures between 65 °C and 105 °C. The reaction follows a first order rate law with an activation energy Ea = 122.3 ±3.0 kJ · mol-1 and an activation volume ⊿V≠ = 1.6 ± 1.0 cm3 mol-1 .

Hochdruckumwandlungen von Cer(III)Orthovanadat(V), CeVO4 / High-Pressure Transformations of Cerium(III) Orthovanadate(V), CeVO4

1990 ◽  
Vol 45 (5) ◽  
pp. 598-602 ◽  
Author(s):  
Klaus-Jürgen Range ◽  
Helmut Meister ◽  
Ulrich Klement
Keyword(s):  
High Pressure ◽  
Triple Point ◽  
High Pressures ◽  
Its Region ◽  
Normal Pressure ◽  
Crystal Data ◽  
High Pressures And Temperatures ◽  
Zircon Type ◽  
High Pressure Apparatus

The polymorphism of CeVO4 was investigated at high pressures and temperatures in a Belttype high-pressure apparatus. In addition to the normal-pressure modification CeVO4— I with zircon-type structure two high-pressure modifications have been found, viz. monazite-type CeVO4—II and scheelite-type CeVO4—III. CeVO4—II is stable between 1 bar and 30 kbar at 1300 °C. Its region of existence decreases rapidly at lower temperatures. From the observed p,T-relations for the I-II and I-III transformations a triple point CeVO4—I,II,III at about 27 kbar, 500 °C can be estimated. For kinetic reasons, however, the experimental determination of phase relations becomes difficult at temperatures below 600 °C.The crystal structures of CeVO4— I and —II have been refined from single-crystal data. Crystallographic data for the three modifications are given and discussed (CeVO4—I: I 41/amd, a = 7.383(1)Å, c = 6.485(1)Å, Z = 4; CeVO4—II: P21/n, a = 7.003(1)Å, b = 7.227(1)Å, c = 6.685(1)Å, β = 105.13(1)°, Z = 4; CeVO4—III: I 41/α, a = 5.1645(2)Å, c = 11.8482(7)Å, Z = 4).

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