A relaxor-ferroelectric material, a method of synthesizing the same and a device including the relaxor-ferroelectric material are provided. The relaxor-ferroelectric material includes a ferroelectric material having a first polarization characteristic. The ferroelectric material having the first polarization characteristics includes a plurality of regions having a second polarization characteristic and spaced apart from each other, and the first polarization characteristic and the second polarization characteristic are different from each other. The ferroelectric material having the first polarization characteristics and the plurality of regions have different response characteristics with respect to alternating current (AC) sweeping. The plurality of regions may include a solid solution.