Thermodynamic and Dielectric Properties of K_1−x(NH₄)_xH₂PO₄ Mixed Crystal

Abstract

We used the cluster pseudospin model for the K_1−x(NH₄)_xH₂PO₄ type proton glasses, which takes into account the energy levels of protons near a PO₄ groups (within the cluster approximation), the long-range interactions between the hydrogen bonds, and an internal random deformation field. We obtained a qualitative description of the temperature behavior of the order parameters, static dielectric permittivity, and the phase diagram of the K_1−x(NH₄)_xH₂PO₄ compounds.

Keywords:

• Hydrogen bond
• proton glass
• dielectric permittivity
• cluster pseudospin model