Dielectric dispersion in [N(CH₃)₃H]₃Sb_2(1-X)Bi_2XCl₉ mixed crystals

Abstract

The dielectric response of pure [N(CH₃)₃H]₃Sb₂Cl₉ (TMACA) and the mixed [N(CH₃)₃H]₃Sb_2(1-X)Bi_2xCl₉ (TMACAB, × = 0.07, 0.33, 0.42) crystals in the frequency range between 75 kHz and 1 GHz was investigated in the vicinity of ferroelectric phase transition. The substitution of Sb by Bi in TMACAB (x < 0.33) caused the shift of the ferroelectric phase transitions point towards the lower temperatures and weakly influenced the dynamic dielectric properties of mixed crystals being isomorphous with pure antimony analogue. The mixed crystals with × = 0.42 appeared to crystallise in different symmetry in comparison to the pure antimony analogue. A clear low frequency relaxation process was found in these last crystals between 300 and 360 K

Key Words:

• halogenoantimonates(III)
• ferroelectrics
• dielectric relaxation
• phase transition