Effect of Hydrostatic Pressure on the Phase Transitions in K₂ZnCl₄

Abstract

Effect of hydrostatic pressure on the normal(I)-incommensurate(II)-ferroelectric(III) phase transitions in K₂ZnCl₄ was studied by differential thermal analysis and dielectric constant measurements. The I–II transition temperature (283°C at 0 GPa) increases with increasing pressure with a rate of 110 K GPa⁻¹. The II–III transition temperature (the ferroelectric Curie temperature: 127°C at 0 GPa) decreases with an initial slope of −86.2 K GPa⁻¹ as pressure increases. The results were compared with previously reported pressure effects of other K₂SeO₄-group ferroelectrics.