Ferroelastic Phase Transition in K3H(SeO4)2
Ferroelastic Phase Transition in K3H(SeO4)2
复制标题
K3H(SeO4)2 中的铁弹性相变
DOI：
10.1143/jpsj.51.1461
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
Takagi Yutaka
中科院分区：
文献类型：
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作者：
Yokota Saburo;Makita Yasuharu;Takagi Yutaka
在25°C ~ 130°C的温度范围内，对K3 H（SeO 4）2的孪晶结构进行了光学观察、晶格形变测量和X射线分析。结果表明，K3 H（SeO 4）2在117°C（Tc）发生反常铁弹相变，室温下具有自发应变e13 =-5.1 × 10 - 3和（e2 2-e11）/2= 4.8 ×10 - 3.晶体为单斜晶系，空间群为A2/ a，低于Tc，三角晶系，空间群为R\bar3m，高于Tc。通过观察和对称性的考虑，阐明了低于Tc的K3 H（SeO 4）2表示相变的两种畴界和三种取向（或畴）。认为相变可能是由k =（1/2）g2的软模引起的。
Optical observation of twin structures, the measurement of lattice deformation and X-ray examinations of K 3 H(SeO 4 ) 2 were carried out in a temperature range between 25°C and 130°C. It was found that K 3 H(SeO 4 ) 2 undergoes the improper ferroelastic phase transition at 117°C ( T c ) and has spontaneous strains e 13 =-5.1×10 -3 and ( e 22 - e 11 )/2=4.8×10 -3 at room temperature. The crystal is monoclinic with the space group A2/ a below T c and trigonal with the space group R\bar3 m above T c . It was clarified by both observation and symmetry consideration that K 3 H(SeO 4 ) 2 below T c indicates two types of domain boundaries and three kinds of orientations (or domains) which appear as a result of the phase transition. It is suggested that the phase transition may be caused by a soft mode with k =(1/2) g 2 .