Thermal Expansion in K₂SeO₄

Abstract

Thermal expansion of K 2 SeO 4 single crystals was measured over the temperature range covering the paraelectric, the intermediate incommensurate, and the ferroelectric commensurate phases. Remarkable change was found at the paraelectric-incommensurate phase transition in all lattice parameters a , b and c . The spontaneous strains x 1s and x 2s along the a and b axes show linear temperature dependence, while the spontaneous strain x 3s along the c axis shows a non-linear temperature dependence.