scholarly journals The influence of Au substitution and hydrostatic pressure on the phase transitions and magnetocaloric properties of MnCoGe alloys

2020 ◽  
Vol 127 (21) ◽  
pp. 213901
Author(s):  
Jing-Han Chen ◽  
Aaron Trigg ◽  
Tej Poudel Chhetri ◽  
David P. Young ◽  
Igor Dubenko ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Hydrostatic Pressure ◽  
Magnetocaloric Properties

NQR study of the structural phase transitions in a system with reduced effective dimensionality: K2ReCl6

1983 ◽  
Vol 61 (10) ◽  
pp. 1374-1381 ◽  
Author(s):  
Marie D'Iorio ◽  
Robin L. Armstrong
Keyword(s):  
Fourier Transform ◽  
Phase Transitions ◽  
Hydrostatic Pressure ◽  
Magnetic Resonance ◽  
Structural Phase ◽  
Nonlinear Phenomena ◽  
Structural Phase Transitions ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
Effective Dimensionality

Chlorine 35 nuclear quadrupole resonance (NQR) frequency and lineshape data, obtained with a Fourier transform magnetic resonance spectrometer, are presented for the antifluorite crystal K2ReCl6. In the temperature range investigated, 85 to 130 K, two structural phase transitions occur which reduce the crystal symmetry from cubic to tetragonal to monoclinic. The variation of the NQR spectrum with temperature and with hydrostatic pressure up to 2.64 kbar is documented. The structure of the spectrum and the intensity distribution within it are unexpected from previous studies of antifluorite systems. An explanation of the results is given which is based on recent discussions of nonlinear phenomena at phase transitions in crystals exhibiting reduced effective dimensionality.

Colossal Barocaloric Effects with Ultralow Hysteresis in Two-Dimensional Metal–Halide Perovskites

2021 ◽  
Author(s):  
Jarad Mason ◽  
Jinyoung Seo ◽  
Ryan McGillicuddy ◽  
Adam Slavney ◽  
Selena Zhang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Phase Transitions ◽  
Solid State ◽  
Hydrostatic Pressure ◽  
Metal Halide ◽  
Two Dimensional ◽  
Vapor Compression ◽  
Entropy Changes ◽  
Halide Perovskites ◽  
Solid State Cooling

Abstract Nearly 4,400 TWh of electricity—20% of the total consumed in the world—is used each year by refrigerators, air conditioners, and heat pumps for cooling. In addition to the 2.3 Gt of carbon dioxide emitted during the generation of this electricity, the vapor-compression-based devices that provided the bulk of this cooling emitted fluorocarbon refrigerants with a global warming potential equivalent to 1.5 Gt of carbon dioxide into the atmosphere. With population and economic growth expected to dramatically increase over the next several decades, the development of alternative cooling technologies with improved efficiency and reduced emissions will be critical to meeting global cooling needs in a more sustainable fashion. Barocaloric materials, which undergo thermal changes in response to applied hydrostatic pressure, offer the potential for solid-state cooling with high energy efficiency and zero direct emissions, as well as faster start-up times, quieter operation, greater amenability to miniaturization, and better recyclability than conventional vapor-compression systems. Efficient barocaloric cooling requires materials that undergo reversible phase transitions with large entropy changes, high sensitivity to hydrostatic pressure, and minimal hysteresis, the combination of which has been challenging to achieve in existing barocaloric materials. Here, we report a new mechanism for achieving colossal barocaloric effects near ambient temperature that exploits the large volume and conformational entropy changes of hydrocarbon chain-melting transitions within two-dimensional metal–halide perovskites. Significantly, we show how the confined nature of these order–disorder phase transitions and the synthetic tunability of layered perovskites can be leveraged to reduce phase transition hysteresis through careful control over the inorganic–organic interface. The combination of ultralow hysteresis (< 1.5 K) and high barocaloric coefficients (> 20 K/kbar) leads to large reversible isothermal entropy changes (> 200 J/kg•K) at record-low pressures (< 300 bar). We anticipate that these results will help facilitate the development of barocaloric cooling technologies and further inspire new materials and mechanisms for efficient solid-state cooling.

Non-Hydrostatic Pressure-Induced Phase Transitions in Self-Assembled Diphenylalanine Microtubes

2018 ◽  
Vol 63 (9) ◽  
pp. 1311-1315 ◽  
Author(s):  
A. Krylov ◽  
S. Krylova ◽  
S. Kopyl ◽  
A. Kholkin
Keyword(s):  
Phase Transitions ◽  
Hydrostatic Pressure ◽  
Self Assembled

Lattice dynamics and hydrostatic-pressure-induced phase transitions in ScF3

2002 ◽  
Vol 94 (5) ◽  
pp. 977-984 ◽  
Author(s):  
K. S. Aleksandrov ◽  
V. N. Voronov ◽  
A. N. Vtyurin ◽  
S. V. Goryainov ◽  
N. G. Zamkova ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Hydrostatic Pressure ◽  
Lattice Dynamics

Magnetic Phase Transitions and Magnetocaloric Properties of Gd5Si0.4In3.6 Compound

2013 ◽  
Vol 320 ◽  
pp. 67-71
Author(s):  
Chao Jing ◽  
X.L. Wang ◽  
D.H. Yu ◽  
Y.J. Yang ◽  
B.J. Kang ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Magnetic Entropy Change ◽  
Magnetic Phase ◽  
Entropy Change ◽  
Ferromagnetic State ◽  
Order Transition ◽  
Magnetic Phase Transitions ◽  
Magnetocaloric Properties ◽  
Second Order Transition ◽  
First Order Transition

The magnetic phase transitions and magnetocaloric properties of Gd5Si0.4In3.6 compound have been investigated. Magnetothermal measurements performed at different conditions reveal that the sample undergoes two magnetic phase transitions. One is a second-order transition from paramagnetic to ferromagnetic state at about 197 K, the other is a first-order transition when the temperature is reduced to 75 K. The magnetocaloric effect around Curie temperature (TC) was calculated in terms of isothermal magnetic entropy change by using Maxwells equation,which remains over a quite wide temperature span of 70 K between the temperature region from160 to 240 K, and thus makes this material attractive for magnetic refrigerator applications.

Hydrostatic Pressure Effect on Phase Transitions of PbHPO4and PbHAsO4

1978 ◽  
Vol 17 (2) ◽  
pp. 437-438 ◽  
Author(s):  
Naohiko Yasuda ◽  
Motohide Okamoto ◽  
Hiroyasu Shimizu ◽  
Sanji Fujimoto ◽  
Katsumi Yoshino ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Hydrostatic Pressure ◽  
Pressure Effect

Phase transitions in PbTe under quasi-hydrostatic pressure up to 50 GPa

2013 ◽  
Vol 33 (4) ◽  
pp. 713-719 ◽  
Author(s):  
Yanchun Li ◽  
Chuanlong Lin ◽  
Hui Li ◽  
Xiaodong Li ◽  
Jing Liu
Keyword(s):  
Phase Transitions ◽  
Hydrostatic Pressure
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