Ferroélectriques classiques ou relaxeurs dérivés de BaTiO3

Abstract

The present work takes stock of either classical or relaxor ferroelectric ceramics related to BaTiO₃. The homovalent substitutions in the 12 C.N. site lead to a sharp transition at T_C and to a classical ferroelectric phase. On the contrary, the substitutions in the 6 C.N. site lead to a diffuse transition, and a relaxor ferroelectric phase; these substitutions may be either homovalent (e.g. Ba(Ti_{1 − x}Zr_x)O₃) or heterovalent (e.g. Ba_{1 − x}K_x(Ti_{1 − x}Nb_x)O₃).