Crossover Between Ferroelectric Order and Dipolar Glass Disorder in CuInP₂(S_0.25Se_0.75)₆ Crystals

Abstract

Dielectric properties of CuInP ₂ (S _0.25 Se _0.75 ) ₆ crystals were investigated in the temperature range 80 < T < 300 K and frequency range 20 Hz < ν < 1.25 GHz. Very broad dielectric relaxation was analyzed in terms of distribution of relaxation times, using Tichonov regularization method. It revealed slowing down of the longest and most probable relaxation times obeying Vogel-Fulcher and Arrhenius laws respectively. The distribution of relaxation times splits into two components near T _m at 1 kHz, and origin of both components are discussed.

Keywords:

• Ferroelectricity
• dielectric dispersion
• dipolar glass
• distribution of relaxation times
• PACS:
• 77.22 Gm
• 77.80 Bh
• 77.84 Bw