| LnP5O14铁弹相变的喇曼光谱研究 |
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| 引用本文： | 陈亭,洪广言.LnP5O14铁弹相变的喇曼光谱研究[J].物理学报,1986,35(11):1521-1527. |
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| 作者姓名： | 陈亭 洪广言 |
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| 作者单位： | (1)南开大学物理系; (2)中国科学院长春应用化学研究所 |
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| 摘 要： | 在200—300℃范围测量了单斜I镧系五磷酸盐LnP5O14(Ln=La,Ce,Pr、Nd,Sm,Eu,Gd,Tb)晶体的软光学模喇曼谱。不同LnP5O14的Ag-B2g和Ag-Ag软模在铁弹相变点都软化到20cm-1,另一个Bg-B3g软模则软化到38cm-1。软模频率对温度的依赖关系表明,这些晶体是很好的平均场理论系统。Ag-B2g软模与e5的耦合对铁弹相变起主要作用,此软模的强度变化可由双向线性模耦合模型来解释。这个系统Tc从La到Tb的增高是镧系收缩的结果。
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| 收稿时间： | 1985-11-08 |
RAMAN-SPECTROSCOPIC STUDY OF FERROELASTIC PHASE TRANSITION IN LANTHANUM PENTAPHOSPHATES |
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| CHEN TING and HONG GUANG-YAN.RAMAN-SPECTROSCOPIC STUDY OF FERROELASTIC PHASE TRANSITION IN LANTHANUM PENTAPHOSPHATES[J].Acta Physica Sinica,1986,35(11):1521-1527. |
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| Authors: | CHEN TING and HONG GUANG-YAN |
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| Abstract: | The soft optic mode spectra of monoclinic I lanthanum pentaphosphates LnP5O14(Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb) are measured in the range of 20-300℃. The Ag-B2g and Ag-Ag soft modes in different LnP5O14 all soften to 20 cm-1 at ferroelastic transition temperature Tc. Another Bg-B3g soft mode softens to 38cm-1 at Tc. The coupling of Ag-B2gsoft mode with e5, plays an essential role in the phase trasition and the temperature dependence of soft-mode intensity can be described by means of the bilinear mode-coupling model. The increment of Tc from La to Tb in this system is owing to the lanthanum contraction. |
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