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Y. Shiozaki - One of the best experts on this subject based on the ideXlab platform.
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Calorimetric measurements of the phase transition in Rochelle Salt–ammonium Rochelle Salt mixed crystals
Physical Review B, 2000Co-Authors: Natsuko Noda, Ryusuke Nozaki, Y. ShiozakiAbstract:The specific heats, which are given with absolute value, of Rochelle Salt--ammonium Rochelle Salt mixed crystals $({\mathrm{RS}}_{1\ensuremath{-}x}\ensuremath{-}{\mathrm{ARS}}_{x})$ in a region $0.18l~xl~0.9$ have been measured between about 10 K and 300 K by an ac calorimetric method. A very small anomaly was found around the transition for any x. It becomes larger as x increases. The anomalies have been well described using the Landau-type free energy expanded to the sixth order of polarization. It was found that, as x increases, the transition point approaches the tricritical point at which a crossover from the second-order phase transition to the first-order one takes place. Transition entropy has been calculated from the anomalous specific heat. It increases from about $8%$ to about $55%$ of $R\mathrm{ln}2$ with increasing x in the measured region. Very small values for small x in this region suggest the displacivelike character in the phase transition. And the order-disorder motion contributes more and more to the phase transition with increasing x.
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calorimetric measurements of the phase transition in Rochelle Salt ammonium Rochelle Salt mixed crystals
Physical Review B, 2000Co-Authors: Natsuko Noda, Ryusuke Nozaki, Y. ShiozakiAbstract:The specific heats, which are given with absolute value, of Rochelle Salt--ammonium Rochelle Salt mixed crystals $({\mathrm{RS}}_{1\ensuremath{-}x}\ensuremath{-}{\mathrm{ARS}}_{x})$ in a region $0.18l~xl~0.9$ have been measured between about 10 K and 300 K by an ac calorimetric method. A very small anomaly was found around the transition for any x. It becomes larger as x increases. The anomalies have been well described using the Landau-type free energy expanded to the sixth order of polarization. It was found that, as x increases, the transition point approaches the tricritical point at which a crossover from the second-order phase transition to the first-order one takes place. Transition entropy has been calculated from the anomalous specific heat. It increases from about $8%$ to about $55%$ of $R\mathrm{ln}2$ with increasing x in the measured region. Very small values for small x in this region suggest the displacivelike character in the phase transition. And the order-disorder motion contributes more and more to the phase transition with increasing x.
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STRUCTURAL CHANGE IN THE PARAELECTRIC PHASE OF AMMONIUM Rochelle Salt
Ferroelectrics, 1999Co-Authors: Katsumi Shimizu, Ryusuke Nozaki, Toshio Kikuta, Y. ShiozakiAbstract:Abstract The crystal structure of ammonium Rochelle Salt in the paraelectric phase are studied by X-ray diffraction. Systematic structural changes are observed as a function of temperature. Hard links, which connect N ion, and oxygen O(8) with rigid tartrate, are extended in a plane parallel to the b-c plane. The oxygen of 0(8) moves against a frame composed of N ions and the direction of the displacement is along the a-axis. The oxygens of O(9) and 0(10) behave as a rigid body against the frame. These features are similar to these in the lower paraelectric phase of Rochelle Salt.
Natsuko Noda - One of the best experts on this subject based on the ideXlab platform.
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calorimetric measurements of the phase transition in Rochelle Salt ammonium Rochelle Salt mixed crystals
Physical Review B, 2000Co-Authors: Natsuko Noda, Ryusuke Nozaki, Y. ShiozakiAbstract:The specific heats, which are given with absolute value, of Rochelle Salt--ammonium Rochelle Salt mixed crystals $({\mathrm{RS}}_{1\ensuremath{-}x}\ensuremath{-}{\mathrm{ARS}}_{x})$ in a region $0.18l~xl~0.9$ have been measured between about 10 K and 300 K by an ac calorimetric method. A very small anomaly was found around the transition for any x. It becomes larger as x increases. The anomalies have been well described using the Landau-type free energy expanded to the sixth order of polarization. It was found that, as x increases, the transition point approaches the tricritical point at which a crossover from the second-order phase transition to the first-order one takes place. Transition entropy has been calculated from the anomalous specific heat. It increases from about $8%$ to about $55%$ of $R\mathrm{ln}2$ with increasing x in the measured region. Very small values for small x in this region suggest the displacivelike character in the phase transition. And the order-disorder motion contributes more and more to the phase transition with increasing x.
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Calorimetric measurements of the phase transition in Rochelle Salt–ammonium Rochelle Salt mixed crystals
Physical Review B, 2000Co-Authors: Natsuko Noda, Ryusuke Nozaki, Y. ShiozakiAbstract:The specific heats, which are given with absolute value, of Rochelle Salt--ammonium Rochelle Salt mixed crystals $({\mathrm{RS}}_{1\ensuremath{-}x}\ensuremath{-}{\mathrm{ARS}}_{x})$ in a region $0.18l~xl~0.9$ have been measured between about 10 K and 300 K by an ac calorimetric method. A very small anomaly was found around the transition for any x. It becomes larger as x increases. The anomalies have been well described using the Landau-type free energy expanded to the sixth order of polarization. It was found that, as x increases, the transition point approaches the tricritical point at which a crossover from the second-order phase transition to the first-order one takes place. Transition entropy has been calculated from the anomalous specific heat. It increases from about $8%$ to about $55%$ of $R\mathrm{ln}2$ with increasing x in the measured region. Very small values for small x in this region suggest the displacivelike character in the phase transition. And the order-disorder motion contributes more and more to the phase transition with increasing x.
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A calorimetric study of the (Rochelle Salt)1−x - (ammonium Rochelle Salt)x mixed crystal system
Ferroelectrics, 1996Co-Authors: Natsuko Noda, Hisashi Haga, Hidehiko Nakano, Ryusuke Nozaki, Yoichi ShiozakiAbstract:Abstract The specific heat of the (Rochelle Salt)1−x - (ammonium Rochelle Salt)x mixed crystal system has been measured in the region III (0.18⩽x≲0.90) with an ac calorimetric technique. A very small anomaly has been observed around the transition temperature. It has been found that the transition entropy, roughly estimated from the anomalous specific heat, depends on x.
Ryusuke Nozaki - One of the best experts on this subject based on the ideXlab platform.
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Disordered feature in Rochelle Salt
Ferroelectrics, 2001Co-Authors: Yoichi Shiozaki, Katsumi Shimizu, Ryusuke NozakiAbstract:Abstract Precise x-ray diffraction study of Rochelle Salt in the paraelectric phase shows that the structure is disorder. The disorder structure does not depend on temperature and it is observed in both the upper paraelectric phase and the lower paraelectric phase. A model is given for the disorder structure to understand the reentrant phase transition.
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calorimetric measurements of the phase transition in Rochelle Salt ammonium Rochelle Salt mixed crystals
Physical Review B, 2000Co-Authors: Natsuko Noda, Ryusuke Nozaki, Y. ShiozakiAbstract:The specific heats, which are given with absolute value, of Rochelle Salt--ammonium Rochelle Salt mixed crystals $({\mathrm{RS}}_{1\ensuremath{-}x}\ensuremath{-}{\mathrm{ARS}}_{x})$ in a region $0.18l~xl~0.9$ have been measured between about 10 K and 300 K by an ac calorimetric method. A very small anomaly was found around the transition for any x. It becomes larger as x increases. The anomalies have been well described using the Landau-type free energy expanded to the sixth order of polarization. It was found that, as x increases, the transition point approaches the tricritical point at which a crossover from the second-order phase transition to the first-order one takes place. Transition entropy has been calculated from the anomalous specific heat. It increases from about $8%$ to about $55%$ of $R\mathrm{ln}2$ with increasing x in the measured region. Very small values for small x in this region suggest the displacivelike character in the phase transition. And the order-disorder motion contributes more and more to the phase transition with increasing x.
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Calorimetric measurements of the phase transition in Rochelle Salt–ammonium Rochelle Salt mixed crystals
Physical Review B, 2000Co-Authors: Natsuko Noda, Ryusuke Nozaki, Y. ShiozakiAbstract:The specific heats, which are given with absolute value, of Rochelle Salt--ammonium Rochelle Salt mixed crystals $({\mathrm{RS}}_{1\ensuremath{-}x}\ensuremath{-}{\mathrm{ARS}}_{x})$ in a region $0.18l~xl~0.9$ have been measured between about 10 K and 300 K by an ac calorimetric method. A very small anomaly was found around the transition for any x. It becomes larger as x increases. The anomalies have been well described using the Landau-type free energy expanded to the sixth order of polarization. It was found that, as x increases, the transition point approaches the tricritical point at which a crossover from the second-order phase transition to the first-order one takes place. Transition entropy has been calculated from the anomalous specific heat. It increases from about $8%$ to about $55%$ of $R\mathrm{ln}2$ with increasing x in the measured region. Very small values for small x in this region suggest the displacivelike character in the phase transition. And the order-disorder motion contributes more and more to the phase transition with increasing x.
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STRUCTURAL CHANGE IN THE PARAELECTRIC PHASE OF AMMONIUM Rochelle Salt
Ferroelectrics, 1999Co-Authors: Katsumi Shimizu, Ryusuke Nozaki, Toshio Kikuta, Y. ShiozakiAbstract:Abstract The crystal structure of ammonium Rochelle Salt in the paraelectric phase are studied by X-ray diffraction. Systematic structural changes are observed as a function of temperature. Hard links, which connect N ion, and oxygen O(8) with rigid tartrate, are extended in a plane parallel to the b-c plane. The oxygen of 0(8) moves against a frame composed of N ions and the direction of the displacement is along the a-axis. The oxygens of O(9) and 0(10) behave as a rigid body against the frame. These features are similar to these in the lower paraelectric phase of Rochelle Salt.
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A calorimetric study of the (Rochelle Salt)1−x - (ammonium Rochelle Salt)x mixed crystal system
Ferroelectrics, 1996Co-Authors: Natsuko Noda, Hisashi Haga, Hidehiko Nakano, Ryusuke Nozaki, Yoichi ShiozakiAbstract:Abstract The specific heat of the (Rochelle Salt)1−x - (ammonium Rochelle Salt)x mixed crystal system has been measured in the region III (0.18⩽x≲0.90) with an ac calorimetric technique. A very small anomaly has been observed around the transition temperature. It has been found that the transition entropy, roughly estimated from the anomalous specific heat, depends on x.
S V Baryshnikov - One of the best experts on this subject based on the ideXlab platform.
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Dielectric studies of nanoporous alumina films filled with the Rochelle Salt
Physics of the Solid State, 2010Co-Authors: S V Baryshnikov, E V Charnaya, E. V. Stukova, A. Yu. Milinskiĭ, Cheng TienAbstract:Dielectric studies of nanoparticles of the Rochelle Salt embedded in pores of porous alumina have been performed in the temperature range from 80 K to the decomposition temperature of the bulk Rochelle Salt. It has been revealed that the permittivity exhibits an anomaly corresponding to the lower structural transition to the paraelectric phase, whereas the upper ferroelectric transition is shifted above the decomposition temperature in agreement with the recently published data. The temperature of the lower transition for nanoparticles in pores is found to decrease by 10 K. Possible physical factors that can be responsible for the broadening of the region of existence of the ferroelectric phase have been discussed.
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Ferroelectricity in Rochelle Salt Nanoparticles Confined to Porous Alumina
Ferroelectrics, 2010Co-Authors: S V Baryshnikov, E V Charnaya, E. V. Stukova, A. Yu. Milinskiy, Cheng TienAbstract:Studies of complex permittivity and third harmonic generation were carried out for a Rochelle Salt loaded porous alumina film within a temperature range from 80 to 325 K in comparison with studies of Rochelle Salt single crystals. Only one peak of real part of permittivity corresponding to the lower (re-entrant) phase transition in confined Rochelle Salt was observed which temperature was reduced by 10 K compared to the relevant temperature in bulk. The upper phase transition was shifted beyond the decomposition temperature in agreement with previous findings. The amplitude of the third harmonic which correlates to the emergence of ferroelectricity was found to be enhanced above 245 K till 325 K. The results obtained evidence the strong extension of the ferroelectric phase in confined Rochelle Salt due to the decrease and the increase of the lower and upper phase transition temperatures, respectively. The physical nature of such extension is discussed.
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NMR studies of structure and ferroelectricity for Rochelle Salt nanoparticles embedded in mesoporous sieves
Journal of Physics: Condensed Matter, 2008Co-Authors: Cheng Tien, E V Charnaya, S V Baryshnikov, Min-kai Lee, Dieter Michel, Winfried BöhlmannAbstract:NMR studies were carried out for Rochelle Salt embedded in molecular sieves. 23 Na magic angle spinning (MAS) and multiple quantum (MQ) MAS NMR spectra revealed a complex structure of the confined crystalline material. The major part of particles within nanopores had a structure similar to that of bulk Rochelle Salt. The 23 Na spin‐lattice relaxation times at various temperatures associated with this modification were also similar to those for bulk Rochelle Salt and showed broad minima that corresponded to the ferroelectric and re-entrant phase transitions under nanoconfinement at temperatures just below the relevant transitions in bulk. This result suggests that the bulk-like modification within pores is ferroelectric in between. Fast spin relaxation in the rest of the confined material reflected high molecular mobility.
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23na spin lattice relaxation in powder Rochelle Salt
Physics of the Solid State, 2007Co-Authors: Cheng Tien, E V Charnaya, M K Lee, S V BaryshnikovAbstract:The temperature dependence of 23 Na spin-lattice relaxation in the polycrystalline Rochelle Salt was studied by NMR within the range from 235 to 320 K covering both Curie points. The spin-relaxation time t1 versus temperature curve showed noticeable dips near the phase transitions against the background of the regular decrease in the relaxation time upon increasing temperature. The dips observed were ascribed to critical contributions to sodium spin-lattice relaxation caused by the slowdown of the correlation time for one of two relaxation modes in the Rochelle Salt. The 23 Na NMR parameters were also measured for the melted Rochelle Salt.
Cene Filipič - One of the best experts on this subject based on the ideXlab platform.
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Dielectric properties of deuterated ammonium Rochelle Salt
Solid state communications, 2017Co-Authors: Robert Blinc, Adrijan Levstik, Cene FilipičAbstract:The dielectric constant of deuterated ammonium Rochelle Salt along the three crystallographic axes as well as the pyroelectric charge density developed on the crystal surface perpendicularly to the b-axis have been measured with a high temperature resolution. The para- to ferroelectric transition at Tc = -159°C shows a thermal hysteresis of ?T = 0.15°C. This and the discontinuities in the dielectric constant along all three axes show that the phase transition is of the first-order. No phase intermediate between the para- and the ferroelectric phases could be detected. © 1984.
