Percolative effects and giant dielectric tunability of BaTiO _3-LuFe_2O_4 composites

摘要

We report on exotic dielectric properties of composite materials consisting of traditional ferroelectric BaTiO_3 and electronic ferroelectric LuFe_2O_4. The composites were synthesized by a simple ceramic processing method with properties that can be tailored by adjusting LuFe_2O_4 concentration. A percolative effect was observed at the volume fraction of ～0.26, which led to an abrupt increase in the dielectric permittivity. For composites with high LuFe_2O_4 fractions, a giant dielectric tunability was observed over a broad temperature interval, which is in strong contrast to traditional ferroelectrics.