Pressure effect on the ferroelectric phase transition in KDP in the cluster approximation of the proton-tunneling model

ABSTRACT

We investigate the pressure dependence of the ferroelectric phase transition in KDP and DKDP in frame of the four-particle cluster approximation of the proton-tunneling model on the assumption of the dipole-dipole interaction nature of the cluster approximation parameters. The obtained values of the derivative somewhat differ from the experimental ones. However, the calculated tricritical point coordinates and the pressure at which the transition vanishes appear to be close to experimental values.

KEYWORDS:

• Ferroelectrics
• KDP
• Landau series
• pressure dependence