Phases Coexistence of Hydrogen-Bonded K_{1 -x}(NH₄)_xH₂PO₄ Crystal

Abstract

The problem of proton-glass and ferroelectric phases coexistence in inhomogeneous ferroelectric K_{1 − x} (NH₄) _x H₂PO₄ abbreviated KADP crystals based on dielectric studies up to temperature 0.3 K is presented. The measurements were performed in the helium-3 cryostat in the temperature range from 300 K to 0.3 K. Glass behavior for the KADP the proton glass occurs for a concentration x > 0.05. The partial phase diagram of KADP as a function of fractional ammonium concentration x and temperature T are presented.

Keywords:

• Ferroelectric
• proton glass
• low temperature
• coexistence

PACS:

• 77.22.Ch
• 77.22.Gm
• 64.70.-p
• 77.80.-e

Acknowledgments

The authors would like to express sincere thanks to: Halina Bartkowiak from Institute of Physics of Adam Mickiewicz University in Poznań for crystal growth, and Authorities of Helium Plant “KRIO” in Odolanów in Poland for delivery of the liquid helium used in our experiments.