Ferroelectric and Hyper Dielectric Modes in Ferronematic Liquid Crystals

Abstract

Binary mixtures of the ferronematic liquid crystal DIO with the recently reported LC non-ferroelectric material WJ-16 exhibiting Colossal Permittivity (CP) ≈ 5000 and superparaelectricity were studied by POM, electrical switching studies, and dielectric spectroscopy. Three mixtures with different WJ-16 contents ranging from 10, 25 to 50% (w/w) in DIO as host were prepared. Our original expectation was the observations of new nematic compositions with both ferroelectric nematic (N F ) and non-ferroelectric CP phases. We found that the non-ferroelectric phase in mixtures exhibits a CP mode, originally observed in pure WJ-16. The dielectric spectroscopy of mixtures shows two distinct relaxation processes: the typical paraelectric response and the CP mode. Therefore, this CP mode in the mixtures is not superparaelectric and here it is defined as a Hyper-dielectric mode. This is the first direct demonstration of mixtures having both ferroelectric and hyper-dielectric phases in liquid crystalline materials.