Colossal dielectric constant and ferroelectric investigation of BaTiO3 nano-ceramics

Abstract

Barium titanate (BaTiO3) nano-ceramics are prepared using nano-ball milling method. Nano-milled samples are calcined at 1200 °C for 6 h to 72 h. Transition from agglomerated growth to fine particles (diameter ~ 350 nm) is observed after nano-ball milling process. Calcination of milled powders at 1200 °C for 6 h and 12 h results in mixed hexagonal and Perovskite BaTiO3 phases. Perovskite phase pure structure is obtained after calcination of 24 h. Further, this phase pure structure is observed to be stable for longer periods of calcination time, i.e., up to 72 h with grain size of ~ 150 nm. Colossal dielectric constant of 1.38 × 106 at log f = 1.3 is observed after calcination for 24 h. Slight increase in dielectric constant, i.e., 2.13 × 106, is observed after calcination for 72 h. Temperature-dependent analyses of sample, calcined at 72 h, exhibit a transition in conduction mechanism at 120 °C. Activation energy of ~ 0.81–1.15 eV is observed for BaTiO3 nano-ceramics. Perovskite BaTiO3 ceramics exhibit saturated ferroelectric hysteresis curves with polarization of 10.28–57.6 μC/cm2. The presence of colossal dielectric constant along with ferroelectricity in BaTiO3 nano-ceramics has potential applications in modern microelectronic devices and for development of novel capacitive data storage devices.