Phase Transition in Hydrogen-Bonded Crystal at Low Temperature under High Pressure

氢键晶体在低温高压下的相变

• 批准号: 12440090
• 负责人: DEGUCHI Kiyoshi
• 金额: $ 5.31万
• 依托单位: Shizuoka Institute of Science and Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12440090/
• 关键词: Ferroelectrics; hydrogen bond; high pressure; KH_2PO_4; CsH_2PO_4; PbHPO_4; 擬一次元性; 圧力誘起相転移; 反強誘電相; 量子常誘電性; 同位元素効果

1. KH_2PO_4 and KD_2PO_4 (1) The crossover of the phase transition mechanism from order-disorder type to displacive type has been found with increasing pressure. (2) The occurrence of the quantum paraelectricty has been observed at low temperature under high pressure2. L_1TIC_4H_40_6H_2O (1) It was found that the ferroelectric phase transition temperature decreases with increasing the deuteron concentration x, and disappears at x, o.95. (2) This isotope effect in the phase transition temperature is explained on the soft-mode theory3. C_3H_2PO_4 (1) The pressure-temperature phase diagram was investigated. Two triple points were found; one is the position where the paraelectric phase (phase I), ferroelectric phase (phase II) and pressure-induced antiferroelectric phase (phase III) meet, and the other is the position where the phase I, phaseII, phaseIII and the second pressure-induced antiferroelectric phase (phaseIX) meet. (2) The pressure-temperature phase diagram obtained in the present work is well described by the quasi-one dimensional Ising model4. PbHPO_4 (1) It was found that the ferroelectric phase transition temperature decreases with increasing pressure, and disappears at 3 Gpa. (2) The pressure-temperature phase diagram of PbHPO_4 is very similar with that KH_2PO_4. Contrary to previous reports, there is no indication for that PbHPO_4 is the qusai-one-dimensional ferroelectric

1. KH_2PO_4和KD_2PO_4（1）随着压力的增加，相变机制由有序-无序型向位移型转变。(2)在低温高压下观察到了量子顺电性的发生2。L_1TIC_4H_4O_6H_2O（1）铁电相变温度随氘浓度x的增加而降低，在x = 0.95时消失。(2)用软模理论解释了相变温度中的同位素效应。（1）研究了C_3H_2PO_4的压力-温度相图。发现了两个三相点;一个是顺电相（相I）、铁电相（相II）和压力诱导反铁电相（相III）相交的位置，另一个是相I、相II、相III和第二压力诱导反铁电相（相IX）相交的位置。(2)在本工作中得到的压力-温度相图是很好地描述准一维伊辛模型4。PbHPO_4（1）铁电相变温度随压力的增加而降低，在3Gpa时相变温度消失。(2)PbHPO_4的压温相图与KH_2PO_4的压温相图非常相似。与以前的报道相反，没有发现PbHPO_4是准一维铁电体的迹象

项目成果

Y.Kobayashi: "Pressure-Temperature Phase Diagram of KNbO_3 Determined by a Dielectric Constant Measurement"Ferroelectrics. Vol.273. 389-394 (2002)

Y.Kobayashi：“通过介电常数测量确定的 KNbO_3 的压力-温度相图”铁电体。

M. Tokunaga: "Vanishing of Order-Disorder Type Phase Transition in DKDP at High Pressure"Ferroelectrics. 237. 169-176 (2000)

M. Tokunaga：“高压 DKDP 中有序-无序型相变的消失”铁电体。

M. Adachi: "Landolt-Bornstein, New series, Group III, Vol.36, Subvol A2. Springer"Ferroelectrics and Related Substances, Oxides: Perovskite-type oxides and LinbO_3 family. 540 (2002)

M. Adachi：“Landolt-Bornstein，新系列，第 III 组，第 36 卷，Subvol A2. Springer”铁电体和相关物质，氧化物：钙钛矿型氧化物和 LinbO_3 族。

M.Adachi (アルファベット順。22名の共同執筆): "Ferroelectrics and Related Substances, Oxides other than Perovskite-type and LiNbO_3 Family (Landolt-Bornstein, New Series, Group III, Vol.36, Subvol. A2)"Springer. 540 (2002)

M.Adachi（按字母顺序排列，22人合着）：“铁电体和相关物质，除钙钛矿型和LiNbO_3族以外的氧化物（Landolt-Bornstein，New Series，Group III，Vol.36，Subvol.A2） ” 施普林格 .540 (2002)

Y. Kobayashi: "The p-T phase diagram of KNbO3 by a Dielectric Constant Measurement"Solid State Commun. 120 No.12. 515-517 (2001)

Y. Kobayashi：“通过介电常数测量得到 KNbO3 的 p-T 相图”Solid State Commun。