铁电陶瓷PMN－PT在室温附近的退极化致冷效应

Depolarizational Refrigeration Effect of PMN-PT Ferroelectric Ceramics near Room Temperature

本文推导了有序熵变化量及温度变化量与外加电场大小、操作温度和材料居里常数之间的关系，在室温附近，对铁电陶瓷ＰＭＮ－ＰＴ的致冷效应进行了测量验证，与理论推导的结论定性吻合，在１６ｋＶ／ｃｍ电场下再退极化，可产生２Ｋ的温度变化，本文并对此效应作了初步的解释。

The ordering entropy of electric dipoles inside a paraelectric salt can be al-tered by applying an electric qield and this prpduces a refrigeration effect.The relationsbetween the entropy change、the temperature change and the intensity of electric field、temperature、the Curie constant of the sample have been obtained on dielectric theory.The depolarizational refrigeration effect of PMN-PT samples near room temperature hasbeen studied and the results of the erperiments qualitatively match the conclusion of the-oretical deducton.A 2 K temperatmpe change can be observed after depolarization under16 kV/cm electric field.The present paper gines a preliminary explanation to this ef-fect.