Microstructural and anomalous resistivity behavior of modified ferroelectric Ba₆Ti₂Nb₈O₃₀

Abstract

The present communication describes the preparation and characterisation of Ba_6-3x R₂ xTi₂Nb₈O₃₀ (where x = 0.0 and 0.05, R = La, Pr, Nd, Sm and Gd) Ceramics. Tetragonal symmetry has been noticed from XRD studies. Microstructural studies using SEM revealed, substitution of rare-earth ion in BTN inhibits the grain growth of BTN. DC resistivity measurements in these compositions indicated PTCR anomalous behaviour. This type of behaviour is explained on the basis of Heywang's model. Curie temperature of rare-earth substituted BTN found to decrease from the value of BTN.

Key Words:

• Ferroelectricity
• microstructure
• curie point
• PTCR