Structural,DielectricandComplexImpedanceSpectroscopyStudiesofLeadFreeCa0.5+xNd0.5-x(Ti0.5Fe0.5)O3

<正>Structural and various electrical properties of polycrystalline Ca0.05+xNd0.5-x(Ti0.5Fe0.5)O3,prepared by standard solid state reaction technique,were studied.Formation of single phase orthorhombic structure of the compositions was confirmed by X-ray diffraction study.The composition dependence of lattice parameters, density and microstructural study show that they vary significantly with Ca content.The dielectric measurements were carried out at room temperature as function of frequency and composition.The experimental results reveal that the dielectric constant（ε'） increases with increasing Ca content.Similar behavior is observed for the dielectric loss（tanδ） and ac conductivity(σac).In complex impedance analysis it is observed that the real part（Z'） vs imaginary part（Z"） graph exhibits a tendency of formation of a single semicircular arc for each composition of samples.Different parameters were determined by fitting the experimental data in Cole—Cole empirical formula.A dominance of grain boundary resistance(Rgb) is observed.The Rgb decreases with increasing Ca content.The highε' observed in present samples are suitable for fabrication of devices.