High-resolution calorimetric study of critical behaviour at the smectic-C*alpha - smectic-C* phase transition
High-resolution calorimetric study of critical behaviour at the smectic-C*alpha - smectic-C* phase transition
复制标题
近晶-C*α - 近晶-C* 相变临界行为的高分辨率量热研究
DOI：
10.1080/02678292.2013.811549
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发表时间：
2013
期刊：
影响因子：
2.2
通讯作者：
K. Ema
中科院分区：
文献类型：
--
作者：
K. Aihara;Y. Sasaki;K. Ema
本文对具有铁电和反铁电相的液晶MHPOBC（[1，1′-联苯基]-4-羧酸，4′-辛氧基-，4-[（1-甲基庚基）氧基]羰基]苯酯）的R-S混合物近晶-近晶相变的热容进行了精确的测量。采用了超低频交流量热仪和高灵敏度差示扫描量热仪。测量结果表明，存在相当缓慢的弛豫附近的过渡。在ac方法中，随着加热频率的降低，伴随着转变的热容异常显着增加。对最接近临界点的混合物的过剩热容进行了定量分析。
Precise heat-capacity measurements have been made around the smectic-–smectic-phase transition in the R–S mixture of liquid crystal MHPOBC ([1, 1′-biphenyl]-4-carboxylic acid, 4′-(octyloxy)-, 4-[[(1-methylheptyl) oxy] carbonyl] phenyl ester) which exhibits ferro-and antiferroelectric phases. Ultra-low frequency ac calorimeter and high-sensitivity differential scanning calorimeter have been used. The measurements revealed the existence of quite slow relaxation near the transition. The heat-capacity anomaly accompanying the transition showed a significant increase as decreasing heat frequency in the ac method. The excess heat capacity observed for a mixture that is closest to the critical point has been analysed quantitatively.