Initial dielectric properties and domain walls area in KDP crystals at low temperatures

Measurements of ∊'c and ∊''c are performed in KDP crystals without d.c. applied electric field at low temperatures, and with a low measuring field amplitude. Employing thermal and electrical cycles, different domain textures are obtained for a given temperature: the ∊'c and ∊''c values display a linear variation with the total domain wall area S. It has been possible to calculate the lateral wall displacement. Such types of measurements are promising to a better understanding of the microscopic processes at the domain wall level.