Dielectric and thermal studies of the low-temperature phase transition in BaCI₂.2H₂O single crystals

Abstract

From specific heat, thermal expansion, and dielectric constant measurements between 150 and 300 K we have confirmed the low temperature phase transition in barium chloride dihydrate (BaCl₂.2H₂O) at 195 ± 1 K. This transition appears to be associated with the local ordering (or displacements) of the two water molecules in the crystal. A “pseudospin” type model is proposed to explain the transition mechanism.

Key Words:

• BaCl₂.2H₂O
• ferroelastic
• heat capacity
• thermal expansion