Investigation of microstructural evolution and suitable potential barrier model for non-linear electrical response of Sr and Nb co-doped CaCu3Ti4O12 ceramics

Abstract

This work reported about impact of co-doping on structural and non-linear electrical property of CaCu 3 Ti 4 O 12 (CCTO) ceramics with composition Ca 0·95 Sr 0·05 Cu 3 Ti 3·94 Nb 0·06 O 12 prepared by solid state reaction technique. Rietveld refinement of X-ray diffraction data was performed to analyse various parameters for its structure exploration. Microstructure and compositional information of prepared ceramic was determined by SEM, EDX and elemental mapping. The grain size was found 2.32 μm with the use of ImageJ software on SEM images. The identical Raman mode were observed in present doped CCTO ceramics comparative to that reported for pure CCTO in Raman spectroscopy. The resistivity of prepared sample reveals NTC behaviour of the ceramic. The parameters; non-linear coefficient (α = 1.86), breakdown electric field (E b = 191.56V/cm) and leakage current (I = 0.44 mA) were obtained by current voltage measurement at room temperature (RT∼303K). The detail comparative study of various barrier models was carried out and found Schottky barriers as most suited model for potential barrier at grain boundaries in the present system. • Ca0·95Sr0·05Cu3Ti3·94Nb0·06O12 ceramic was synthesized using Solid State Reaction method. • Structural Properties were investigated by XRD, SEM, Raman and FT-IR spectroscopy. • Schottky emission model was found most suitable for non-linear electrical response of prepared ceramics. • The value of nonlinear coefficient and Breakdown field suggest it was suitable for low voltage application. • The present sample exhibits good NTC behaviour at low DC voltage and found useful for varistor and thermistor application.