Dielectric properties versus sample thickness in KH₂PO₄ ferroelectric crystals

Abstract

The dielectric constant ϵ′ _c and the loss constant e“_c of KDP crystals are measured in the ferroelectric phase versus the sample thickness t. It is experimentally demonstrated that the ϵ′_c values change with t and become maximum for t approximately equal to one half of the other sample dimensions (in a axes directions). Then, it is shown that the domain freezing temperature T _f which corresponds to the low temperature e“( _T ) maximum, decreases with the sample thickness in a logarithmic law.