Phase transitions, critical dielectric phenomena and hysteresis effects in betaine calcium chloride dihydrate

Abstract

Single crystals of betaine calcium chloride dihydrate ((CH₃)₃NCH₂COO*CaCl₂*2H₂0) are grown from aqueous solutions. The dielectric constant shows several distinct anomalies with the highest values of about 20000 near 125 K. Below this temperature complex dielectric hysteresis loops are observed. Their shape strongly depends on temperature, field and frequency. Below 51 K only single loops can be obtained which probably indicate a ferroelectric phase.