THE LA4TI3O12-BALA4TI4O15 SYSTEM - STRUCTURAL CHARACTERIZATION AND DIELECTRIC-PROPERTIES

A series of microphases with trigonal symmetry and general formula A(n )Ti(n-1)O3(n) (A=La,Ba) have been observed as different intergrowths o f La4Ti3O12 (n=4) and BaLa4Ti4O15 (n=5). Perfectly ordered intergrowth s labelled 4(1)5(1), 4(2)5(1),..., 4(6)5(1) - 4(P)5(Q) corresponds to the intergrowth of P (n=4) structural units and Q (n=5) structural uni ts - have been characterized by X-ray diffraction and transmission ele ctron microscopy. Dielectric measurements showed that ceramic bodies w ith 92% of the theoretical density showed good thermal stability of th e permittivity and dielectric loss between 200 Hz and 1 MHz. Significa nt conductivity was observed above 750 degrees C.