Anisotropic giant dielectric tunability in electronic ferroelectric YbFe2O4

We have studied the dielectric properties of YbFe2O4 single crystals, which exhibits ferroelectricity due to charge ordering. The dielectric constant of both the c-axis and ab-plane exhibit a large dielectric dispersion, and is greatly suppressed by applying a small DC bias electric field, which leads to a giant dielectric tunability. Due to the layered structure, a strong anisotropy between the c-axis and ab-plane is observed in the dielectric constant, tunability, and loss tangent. The origin of the giant dielectric tunability and dielectric loss is discussed based on the nature of electronic ferroelectricity.