scholarly journals Prediction of a new phase transition in Al2O3at high pressures

2005 ◽  
Vol 32 (6) ◽  
Author(s):  
R. Caracas
Author(s):  
Kun Li ◽  
Junjie Wang ◽  
Vladislav A. Blatov ◽  
Yutong Gong ◽  
Naoto Umezawa ◽  
...  

AbstractAlthough tin monoxide (SnO) is an interesting compound due to its p-type conductivity, a widespread application of SnO has been limited by its narrow band gap of 0.7 eV. In this work, we theoretically investigate the structural and electronic properties of several SnO phases under high pressures through employing van der Waals (vdW) functionals. Our calculations reveal that a metastable SnO (β-SnO), which possesses space group P21/c and a wide band gap of 1.9 eV, is more stable than α-SnO at pressures higher than 80 GPa. Moreover, a stable (space group P2/c) and a metastable (space group Pnma) phases of SnO appear at pressures higher than 120 GPa. Energy and topological analyses show that P2/c-SnO has a high possibility to directly transform to β-SnO at around 120 GPa. Our work also reveals that β-SnO is a necessary intermediate state between high-pressure phase Pnma-SnO and low-pressure phase α-SnO for the phase transition path Pnma-SnO →β-SnO → α-SnO. Two phase transition analyses indicate that there is a high possibility to synthesize β-SnO under high-pressure conditions and have it remain stable under normal pressure. Finally, our study reveals that the conductive property of β-SnO can be engineered in a low-pressure range (0–9 GPa) through a semiconductor-to-metal transition, while maintaining transparency in the visible light range.


2012 ◽  
Vol 26 (28) ◽  
pp. 1250183 ◽  
Author(s):  
VLADIMIR NAZAROV ◽  
RISHAT SHAFEEV

Theoretically, with the aid of a soliton model, the evolution of a new-phase nucleus near the first-order spin-reorientation phase transition in magnets has been investigated in an external magnetic field. The influence of an external field and one-dimensional defects of magnetic anisotropy on the dynamics of such nucleus has been demonstrated. The conditions for the localization of the new-phase nucleus in the region of the magnetic anisotropy defect and for its escape from the defect have been determined. The values of the critical fields which bring about the sample magnetization reversal have been identified and estimated.


1981 ◽  
Vol 67 (2) ◽  
pp. K123-K125 ◽  
Author(s):  
J. Majszczyk ◽  
J. Rączka ◽  
Z. Czapla
Keyword(s):  

2002 ◽  
Vol 65 (10) ◽  
Author(s):  
A. Grzechnik ◽  
K. Syassen ◽  
I. Loa ◽  
M. Hanfland ◽  
J. Y. Gesland

1982 ◽  
Vol 51 (1) ◽  
pp. 199-202 ◽  
Author(s):  
Saburo Yokota ◽  
Nobuhiro Takanohashi ◽  
Toshio Osaka ◽  
Yasuharu Makita

1996 ◽  
Vol 196 (1) ◽  
pp. 39-47
Author(s):  
L. Bobrowicz ◽  
A. Katrusiak ◽  
W. Nawrocik ◽  
J. Wasicki ◽  
I. Natkaniec

2019 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Yu.V. Yudin ◽  
M.V. Maisuradze ◽  
A.A. Kuklina ◽  
P.D. Lebedev

An algorithm was developed for the simulation of a phase transition in solid state whichmakes it possible to obtain the kinetic curves of transformation under different initialconditions (the number and arrangement of new phase nuclei, the distance betweenthe nearest nuclei). The simulation results were analyzed using the Kolmogorov-Johnson-Mehl-Avrami equation and the corresponding coefficients were determined.The correlation between the simulation results and the experimental kinetics of theaustenite isothermal transformation in alloyed steels was shown.


2002 ◽  
Vol 12 (9) ◽  
pp. 381-384
Author(s):  
N. Matsunaga ◽  
A. Ayari ◽  
P. Moncea ◽  
K. Yamashita ◽  
A. Ishikawa ◽  
...  

Magnetoresistance and Hall resistance measurements have been carried out in the FISDW phase of deuterated (TMTSF)2C1O4 for various cooling rates through the anion ordering temperature. The Hall resistance in the intermediate cooled state, observed a very stable quantum Hall state above 9.0 T for slowly cooled, shows a step-like change from the phase between 10 and 17 T to the phase between 20 and 25 T with hysteresis between 14 and 21 T. This result suggests that there is a new phase transition around 15 T in deuterated (TMTSF)4ClO4. A possible ground state of the FISDW phase of (TMTSF)2C1O4 for various cooling rates is discussed from the viewpoint of the peculiar SDW nesting vector stabilized by the dimerized gap due to anion ordering.


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