LV. The optical and electrical properties of single crystals of sodium niobate
LV. The optical and electrical properties of single crystals of sodium niobate
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DOI：
10.1080/14786440508520582
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发表时间：
1955-05
期刊：
影响因子：
--
通讯作者：
L. Cross;B. J. Nicholson
中科院分区：
文献类型：
--
作者：
L. Cross;B. J. Nicholson
在-190 ° C ~+650 ° C温度范围内测量了钨酸钠小单晶的光学应变和介电常数。在室温下的性能是一致的反铁电结构，并为垂直于正交c轴施加高场，双磁滞曲线已被观察到。在低温下，有证据表明铁电性能的领域平行于c轴。在最完美的晶体中，居里温度低于-209 ° c，但铁电相可能由高电场诱导。这种变化有一个很长的热滞后，一旦转变，晶体在-55 ° C仍保持铁电性。在350°C以上，对称性仅为假四方晶系，真正的正交晶系，在470°C和518°C观察到两个较小的结构变化，然后在638°C结构变为立方晶系。
Abstract The optical strains and dielectric constants of small single crystals of sodium niobate have been measured over the temperature range -190°c to +650°c. At room temperature the properties are consistent with an antiferroelectric structure, and for high fields applied perpendicular to the orthorhombic c axis, double hysteresis curves have been observed. At low temperature there is evidence of ferroelectric properties for fields applied parallel to the c axis. In the most perfect crystals the Curie temperature is below -209°c, but the ferroelectric phase may be induced by a high electric field. There is a long thermal hysteresis on this change and once transformed the crystals remain ferroelectric to -55°c. Above 350°c the symmetry is only pseudo-tetragonal, truly orthorhombic, and two minor structure changes, at 470°c and 518°c are observed, before the structure becomes cubic at 638°c.