Investigation of Ferroelectric Phase Transition of Rochelle Salt

Abstract

The phenomenological theory has been applied to investigate the phase transition of the Rochelle salt crystal. The Helmholtz free energy expansion of the Rochelle salt crystal is obtained by using the basis functions of all the irreducible representations of the paraelectric phase group D ₂ . An appropriate explanation of the existence of two Curie temperatures in the ferroelectric phase transition of the Rochelle salt crystal is put forward. The temperature dependence of the spontaneous polarization is obtained. The independent components of the reciprocal susceptibility in both the paraelectric phase and the ferroelectric phase are calculated out. The theoretical curves of the spontaneous polarization and the main reciprocal susceptibility ζ ₁₁ varying with the temperature accord with the experimental results of other literatures.

Keywords:

• Helmholtz free energy
• phenomenological theory
• irreducible representation
• Curie temperature
• spontaneous polarization
• reciprocal susceptibility

PACS:

• 77.80.Bh
• 77.80.-e
• 61.50.Ah
• 02.20.-a

Acknowledgment

This work was supported by the National Natural Science Foundation of China under Grant No. 10647120 and by the Research and Development Project of Hebei Provincial Science and Technology under Grant No. 06547002D-2.