scholarly journals Stabilization of an ambient-pressure collapsed tetragonal phase in CaFe2As2and tuning of the orthorhombic-antiferromagnetic transition temperature by over 70 K via control of nanoscale precipitates

2011 ◽  
Vol 83 (14) ◽  
Author(s):  
S. Ran ◽  
S. L. Bud’ko ◽  
D. K. Pratt ◽  
A. Kreyssig ◽  
M. G. Kim ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Tetragonal Phase ◽  
Ambient Pressure ◽  
Antiferromagnetic Transition

A tetragonal polymorph of SrMn2P2made under high pressure – theory and experiment in harmony

2017 ◽  
Vol 46 (21) ◽  
pp. 6835-6838 ◽  
Author(s):  
Weiwei Xie ◽  
Michał J. Winiarski ◽  
Tomasz Klimczuk ◽  
R. J. Cava
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Tetragonal Phase ◽  
Ambient Pressure ◽  
Structure Type ◽  
Space Group ◽  
Type Space ◽  
Tetragonal Phase Transition ◽  
Theory And Experiment

A trigonal–tetragonal phase transition in SrMn2P2is proposed and confirmed experimentally under high pressure. At ambient pressure, SrMn2P2crystallizes in the primitive trigonal La2O3structure type (space groupP3̄m1) in blue. Under high pressure, the tetragonal ThCr2Si2structure type (space groupI4/mmm) in red is more stable.

High Pressure Properties of Superconducting Material Palladium

2013 ◽  
Vol 813 ◽  
pp. 327-331
Author(s):  
Wei Min Peng ◽  
Zhong Li Liu ◽  
Hong Zhi Fu
Keyword(s):  
High Pressure ◽  
Perturbation Theory ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Density Functional ◽  
High Pressures ◽  
Ambient Pressure ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Density Functional Perturbation Theory

The electronic and the superconducting properties of Pd were studied in the framework of density functional perturbation theory. We explored the superconducting transition temperature for bulk Pd and predicted possible superconductivity at ambient and high pressures. It is found that of Pd is 0.0356 K at ambient pressure and it decreases with pressure.

scholarly journals ON DISCOVERY OF THE FERROMAGNETIC SUPERCONDUCTOR UCoGe

2011 ◽  
Vol 14 (2) ◽  
pp. 21-28
Author(s):  
Huy Thanh Nguyen ◽  
Cuong Duc Dao ◽  
Thu Thanh Vu ◽  
An Tu Bui
Keyword(s):  
Transition Temperature ◽  
Curie Temperature ◽  
Ambient Pressure ◽  
Spin Fluctuations ◽  
Resistive Transition ◽  
Unconventional Superconductor ◽  
Present Evidence ◽  
Microscopic Scale ◽  
Weak Ferromagnet ◽  
Curie Temperature Tc

We report the coexistence of ferromagnetic order and superconductivity in UCoGe at ambient pressure. The data obtained from the basic thermal, magnetic and transport properties on the macro and microscopic scale show that UCoGe is a weak ferromagnet with a Curie temperature TC = 3 K, and also, is a superconductor with a resistive transition temperature Ts = 0.8 K. Those present evidence that UCoGe is an unconventional superconductor and argue that superconductivity is mediated by critical ferromagnetic spin fluctuations.

Ab initio Study of the Amorphous Cu-Bi System

MRS Advances ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 81-86
Author(s):  
D. Hinojosa-Romero ◽  
I. Rodriguez ◽  
A. Valladares ◽  
R. M. Valladares ◽  
A. A. Valladares
Keyword(s):  
Transition Temperature ◽  
Ab Initio ◽  
Ambient Pressure ◽  
Amorphous State ◽  
Amorphous Structure ◽  
Ab Initio Molecular Dynamics ◽  
Superconducting Transition ◽  
Amorphous System ◽  
Densities Of States ◽  
Quench Method

ABSTRACTAs a pure element, bismuth is a semimetal which possesses several interesting physical properties, not all of them well understood. The recent discovery of superconductivity, as predicted by our group, and the increasing superconducting transition temperature as the pressure applied increases, are some examples of its particularities. Also, the fact that the amorphous phase is superconductive with a transition temperature several orders of magnitude larger than the crystalline at ambient pressure is unusual. These phenomena have also motivated our predictions for the transition temperatures of Bi-bilayers and the Bi-IV phase. When mixed with other elements, bismuth seems to contribute to the superconducting character of the resulting material. Here we study the binary copper-bismuth amorphous system which is known to superconduct in diverse compositions. Using ab initio molecular dynamics and the undermelt-quench method, we generate an amorphous structure for a 144-atom supercell corresponding to the Cu61Bi39 system. We calculate the electronic and vibrational densities of states for the amorphous system and estimate a superconducting critical temperature of 4.2 K for the amorphous state.

Texture on Ground, Fractured, and Aged Y-TZP Surfaces

1986 ◽  
Vol 78 ◽  
Author(s):  
Franz Reidinger ◽  
Philip J. Whalen
Keyword(s):  
Phase Composition ◽  
Transition Temperature ◽  
Diffraction Analysis ◽  
Surface Treatment ◽  
Tetragonal Phase ◽  
Surface Region ◽  
X Ray Diffraction ◽  
X Ray ◽  
History Of

ABSTRACTThe phase composition of Y-TZP surfaces has been shown to vary greatly depending on the thermo-mechanical history of the surface. The orientation of these different phases in the surface region is not always random. There is speculation that the alignment of the tetragonal phase before fracturing may play a part in increasing the toughness of these materials. This article deals with an X-ray diffraction analysis of various Y-TZP surfaces with special emphasis on the texture of the different phases. Surfaces which have been ground (and polished), fractured, and aged (200°C) have been examined. In all cases, the monoclinic component that was formed was strongly oriented. The tetragonal phase may or may not be oriented depending on surface treatment. Annealing above the monoclinic-tetragonal transition temperature had little effect on the tetragonal orientation in most cases. Samples fractured at 1000°C have no unusual orientation on the fracture faces.

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