Dielectric Properties of Rb₂CdBr₄ and Rb₂HgBr₄

Abstract

Phase transitional properties of Rb₂CdBr₄ and Rb₂HgBr₄ were investigated. The differential thermal analysis for Rb₂CdBr₄ indicates the same supercooled nature of the phase transition as observed in A₂BX₄-type halides with the structure of Sr₂GeS₄-type. On the other hand, the temperature dependence of the dielectric constant of Rb₂HgBr₄ shows two anomalies at low temperatures, which are analogous to those of Cs₂HgBr₄ and Cs₂ZnI₄ with the structure of orthorhombic β -K₂SO₄-type.

Keywords:

• Rb₂CdBr₄
• Rb₂HgBr₄
• phase transition
• Sr₂GeS₄ structure
• β
• -K₂SO₄ structure
• α-β transition