Structure and dielectric properties of Pb1−xCax(Yb0.5Nb0.5)1−x(Fe0.5Nb0.5)xO3 ceramics

The crystal structure and dielectric properties of Pb1−xCax(Yb0.5Nb0.5)1−x(Fe0.5Nb0.5)xO3 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) have been investigated in this paper by X-ray diffraction (XRD), dielectric and Raman spectroscopic measurements. The crystal structure of Pb1−xCax(Yb0.5Nb0.5)1−x(Fe0.5Nb0.5)xO3 changes from the orthorhombic to the pseudocubic phase with local non-uniform distribution of B-site cations at room temperature when x = 0.2. With the further increase of x value, the sample exhibits the phase mixture of pseudocubic phase and Ca(Fe1/2Nb1/2)O3 (CFN). The dielectric constant increases with the increase of x value up to x = 0.2 and decreases with the further increase of x value. The sample exhibits typical dielectric relaxor behavior when x = 0.2 and 0.4.