New annealing method to improve KD2PO4 crystal quality: learning from high temperature phase transition
New annealing method to improve KD2PO4 crystal quality: learning from high temperature phase transition
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DOI：
10.1039/c5ce00813a
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发表时间：
2015-06
期刊：
影响因子：
3.1
通讯作者：
Lisong Zhang;Mingxia Xu;Bao’an Liu;Lili Zhu;Bo Wang;Hailiang Zhou;Fafu Liu;Xun Sun
中科院分区：
文献类型：
--
作者：
Lisong Zhang;Mingxia Xu;Bao’an Liu;Lili Zhu;Bo Wang;Hailiang Zhou;Fafu Liu;Xun Sun
热分析、介电分析和拉曼光谱证实了KD2PO4中存在高温相变。结果表明，KD2PO4在TtR=430K附近只有一次高温相变，远低于热分解温度。由于脱水产物没有拉曼频移，表明HTPT与热分解无关。讨论了高温超导过程中的结构变化。KD2PO4晶体中的HTPT相与四方相具有很强的相似性，降低了HTPT的温度。在保护的环境下可以抑制氢-氚交换，这有助于提高退火温度。为了提高KD2PO4晶体的质量，提出了一种利用硅油作为保护环境，在高温至403K条件下对KD2PO4晶体进行热处理的方法。
The existence of a high temperature phase transition in KD2PO4 was confirmed by thermal analysis, dielectric analysis and Raman spectroscopy. The results showed that KD2PO4 presented only one high temperature phase transition at about Ttr = 430 K, which is much lower than the thermal decomposition temperature. The absence of Raman shift attributable to the dehydration product indicated that the HTPT had nothing to do with thermal decomposition. The structural change during the HTPT was discussed. The strong similarity between the HT-phase and tetragonal phase decreases the temperature of the HTPT in the KD2PO4 crystal. The hydrogen–deuterium exchange can be suppressed under a protective ambient environment, which helps improve the annealing temperature. A new annealing method was developed by using silicone oil as a protective ambient environment under higher temperature up to 403 K, thus improving the quality of KD2PO4 crystals.