Dielectric, pyroelectric, piezoelectric and optical investigation of the phase transition sequence in BaZnGeO4

We investigate electric and magnetic properties of quasi-one-dimensional transition-metal carbides Sc3TC4 (T = Co, Ru, and Os), and their mixed crystals Sc3(Co1-xRux)C4 and Sc3(Ru1-xOsx)C4. Sc3CoC4 exhibits successive phase transitions of charge-density-wave transition at TCDW ~ 140 K, Peierls-like structural transition at Ts ~ 70 K, and superconducting transition at Tc ~ 5 K. Sc3RuC4 and Sc3OsC4 exhibit a phase transition at T* ~ 220 K and 250 K, respectively, which should occur in the low-dimensional electronic structure. For Sc3CoC4, it is revealed by the investigation of the electric and magnetic properties of Sc3(Co1-xRux)C4 that the phase transitions at TCDW, Ts, and Tc exhibit different robustness against Ru doping. For Sc3RuC4 and Sc3OsC4, it is revealed by the investigation of the electric and magnetic properties of Sc3(Ru1-xOsx)C4 that an identical kind of phase transition occurs at T*. Additionally, the present study reveals that the phase transition at T* in Sc3RuC4 and Sc3OsC4 is inherently different from the phase transitions at TCDW, Ts, and Tc in Sc3CoC4.

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Ferroelectric Phase Transition Investigated by Thermal Analysis and Raman Scattering in SrBi2Ta2O9 Nanoparticles

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.121-123.843 ◽

2007 ◽

Vol 121-123 ◽

pp. 843-846 ◽

Cited By ~ 4

Author(s):

Hua Ke ◽

De Chang Jia ◽

Wen Wang ◽

Yu Zhou

Keyword(s):

Phase Transition ◽

Thermal Analysis ◽

Particle Size ◽

Phase Transitions ◽

Size Effect ◽

Raman Spectra ◽

Ferroelectric Phase Transition ◽

Ferroelectric Phase ◽

Intermediate Phase ◽

Transition Sequence

Thermal analysis and Raman spectra were carried out in SrBi2Ta2O9 (SBT) nanoparticles to investigate phase transitions. Two anomalies have been observed in temperature dependence of specific heat for SBT nanoparticles. Under the combination with Raman spectra, it indicates that there exists a new ferroelectric intermediate phase in the phase-transition sequence. So we can conclude that the phase-transition sequence in SBT nanoparticles should be ferroelectric-ferroelectric-paraelectric. Moreover, the size effect was discussed in consideration of inner compressive stress in nanoparticles for this special transition behavior. The calculated results show that the SBT nanoparticles keep the ferroelectricity until the particle size is decreased to 4.2 nm.

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81Br and 127I NQR and Phase Transitions in CH3NH3 HgBr3 and CH3NH3 HgI3

Zeitschrift für Naturforschung A ◽

10.1515/zna-1990-3-422 ◽

1990 ◽

Vol 45 (3-4) ◽

pp. 343-348 ◽

Cited By ~ 9

Author(s):

Hiromitsu Terao ◽

Tsutomu Okuda

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Large Amplitude ◽

Molecular Motions ◽

Temperature Variations ◽

Halogen Atoms ◽

Resonance Frequencies ◽

Successive Phase

Abstract The 81Br and 127I NQR spectra were recorded in CH3NH3 HgBr3 and CH3NH HgI3 , respectively. In addition to a phase transition at 338 K, successive phase transitions take place at 127 ± 1, 184±1 and 243±5 K in CH3NH3 HgBr3. On heating, the resonance lines of CH3NH3HgI3 disappear near a phase transition at 328 K and one line appears above this temperature. The temperature variations of the resonance frequencies of the terminal halogen atoms in both crystals are extraordinarily steep. This indicates the large amplitude molecular motions expected for the CH3NH3 cations which are linked to the terminal halogen atoms through N-H ··· X type H-bonding.

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Phase Transitions in 4,4´-Dichlorobenzophenone as Studied by 35Cl FT-NQR

Zeitschrift für Naturforschung A ◽

10.1515/zna-1994-1-239 ◽

1994 ◽

Vol 49 (1-2) ◽

pp. 267-272 ◽

Cited By ~ 4

Author(s):

Hirokazu Nakayama ◽

Taro Eguchi ◽

Nobuo Nakamura

Keyword(s):

Phase Transition ◽

Fourier Transform ◽

Phase Transitions ◽

Room Temperature ◽

Thermal Hysteresis ◽

Thermal Anomaly ◽

Hysteresis Phenomenon ◽

Transform Method ◽

Three Phase ◽

Successive Phase

Abstract The temperature dependence of 35Cl NQR frequencies in 4,4´-dichlorobenzophenone was measured between 9.3 and 372 K by the pulse Fourier-transform method. Successive phase transitions were observed at 189 and 194 K. Concerning these phase transitions, the curious thermal hysteresis phenomenon found in a previous NQR experiment was not reproduced in the present study. It also follow s that NQR indicates another phase transition around 220 K, although no thermal anomaly was detected there by DTA. Tentative explanations for these three phase transitions are presented in relation to the incommensurability between 189 and 220 K. In addition, a novel phase transition was found to occur at 331 K according to both DTA and 35Cl NQR. A single NQR line observed at room temperature splits into two components above 331 K, suggesting that the symmetry above 331 K is lower than that at room temperature. This is the behavior of re-entrant phase transition, and it reveals the quasi-continuous nature.

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A Veritable Zoology of Successive Phase Transitions in the Asymmetric q-Voter Model on Multiplex Networks

Entropy ◽

10.3390/e22091018 ◽

2020 ◽

Vol 22 (9) ◽

pp. 1018

Author(s):

Anna Chmiel ◽

Julian Sienkiewicz ◽

Agata Fronczak ◽

Piotr Fronczak

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Continuous Phase ◽

Voter Model ◽

Complete Graphs ◽

Opinion Formation ◽

Multiplex Networks ◽

Multiplex Network ◽

Two Parameters ◽

Successive Phase

We analyze a nonlinear q-voter model with stochastic noise, interpreted in the social context as independence, on a duplex network. The size of the lobby q (i.e., the pressure group) is a crucial parameter that changes the behavior of the system. The q-voter model has been applied on multiplex networks, and it has been shown that the character of the phase transition depends on the number of levels in the multiplex network as well as on the value of q. The primary aim of this study is to examine phase transition character in the case when on each level of the network the lobby size is different, resulting in two parameters q1 and q2. In a system of a duplex clique (i.e., two fully overlapped complete graphs) we find evidence of successive phase transitions when a continuous phase transition is followed by a discontinuous one or two consecutive discontinuous phase transitions appear, depending on the parameter. When analyzing this system, we even encounter mixed-order (or hybrid) phase transition. The observation of successive phase transitions is a new quantity in binary state opinion formation models and we show that our analytical considerations are fully supported by Monte-Carlo simulations.

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Successive phase transitions in the MeLiBO4type crystals

Ferroelectrics ◽

10.1080/00150198508221380 ◽

1985 ◽

Vol 63 (1) ◽

pp. 13-28 ◽

Cited By ~ 7

Author(s):

K. S. Aleksandrov ◽

D. H. Blat ◽

V. I. Zinenko ◽

I. M. Iskornev ◽

R. F. Klevtsova ◽

...

Keyword(s):

Phase Transitions ◽

Successive Phase

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Electric properties of olive oil under pressure

European Food Research and Technology ◽

10.1007/s00217-021-03761-7 ◽

2021 ◽

Author(s):

L. T. Pawlicki ◽

R. M. Siegoczyński ◽

S. Ptasznik ◽

K. Marszałek

Keyword(s):

Molecular Structure ◽

Phase Transition ◽

Phase Diagram ◽

Phase Transitions ◽

Olive Oil ◽

Material Parameters ◽

First Order ◽

Long Time ◽

Capacitive Reactance ◽

First Order Phase

AbstractThe main purpose of the experiment was a thermodynamic research with use of the electric methods chosen. The substance examined was olive oil. The paper presents the resistance, capacitive reactance, relative permittivity and resistivity of olive. Compression was applied with two mean velocities up to 450 MPa. The results were shown as functions of pressure and time and depicted on the impedance phase diagram. The three first order phase transitions have been detected. All the changes in material parameters were observed during phase transitions. The material parameters measured turned out to be the much more sensitive long-time phase transition factors than temperature. The values of material parameters and their dependence on pressure and time were compared with the molecular structure, arrangement of molecules and interactions between them. Knowledge about olive oil parameters change with pressure and its phase transitions is very important for olive oil production and conservation.

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Room-temperature NaI/H2O compression icing: solute–solute interactions

Physical Chemistry Chemical Physics ◽

10.1039/c7cp03919k ◽

2017 ◽

Vol 19 (39) ◽

pp. 26645-26650 ◽

Cited By ~ 20

Author(s):

Qingxin Zeng ◽

Chuang Yao ◽

Kai Wang ◽

Chang Q. Sun ◽

Bo Zou

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Bond Energy ◽

Room Temperature ◽

Solute Concentration ◽

Solute Interaction ◽

Solute Interactions

H–O bond energy governs the PCx for Na/H2O liquid–VI–VII phase transition. Solute concentration affects the path of phase transitions differently with the solute type. Solute–solute interaction lessens the PC2 sensitivity to compression. The PC1 goes along the liquid–VI boundary till the triple phase joint.

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The origin of the lattice thermal conductivity enhancement at the ferroelectric phase transition in GeTe

npj Computational Materials ◽

10.1038/s41524-021-00523-7 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Đorđe Dangić ◽

Olle Hellman ◽

Stephen Fahy ◽

Ivana Savić

Keyword(s):

Phase Transition ◽

Thermal Conductivity ◽

Phase Transitions ◽

Thermoelectric Materials ◽

Ferroelectric Phase Transition ◽

Lattice Thermal Conductivity ◽

Ferroelectric Phase ◽

Structural Phase ◽

High Symmetry ◽

Structural Phase Transitions

AbstractThe proximity to structural phase transitions in IV-VI thermoelectric materials is one of the main reasons for their large phonon anharmonicity and intrinsically low lattice thermal conductivity κ. However, the κ of GeTe increases at the ferroelectric phase transition near 700 K. Using first-principles calculations with the temperature dependent effective potential method, we show that this rise in κ is the consequence of negative thermal expansion in the rhombohedral phase and increase in the phonon lifetimes in the high-symmetry phase. Strong anharmonicity near the phase transition induces non-Lorentzian shapes of the phonon power spectra. To account for these effects, we implement a method of calculating κ based on the Green-Kubo approach and find that the Boltzmann transport equation underestimates κ near the phase transition. Our findings elucidate the influence of structural phase transitions on κ and provide guidance for design of better thermoelectric materials.

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