Linear, Non-Linear, and Ferroelectric behavior in 0-3 Nanoparticle-Polymer Dielectrics of Ba(Ti, MV)O3 (M = Nb, Ta)

Nanodielectrics based upon nanoscale Ba(Ti, M^V)O₃, where M = Nb or Ta, were prepared and electrically characterized for their potential use as a high permittivity dielectric layer. Nanocrystals of Ba(Ti, Nb)O₃ (BTNO) and Ba(Ti, Ta)O₃ (BTTO) of average size 20 nm (range 10-50 nm) with a non-centrosymmetric (polarizable) crystal structure were synthesized, dispersed in alcohol solvents and blended with three polymers of known but differing dielectric and electromechanical behavior: Polyvinylpyrrolidone (PVP), Polyfurfuryl alcohol (PFA) and Polyvinylidene fluoride–trifluoroethylene (PVDF-TrFE). 0-3 nanoparticle-polymer pressed pellets, films and metal-insulator-metal devices were prepared for electrical characterization. Analysis of the Ba(Ti, M^V)O₃-PVP and Ba(Ti, M^V)O₃ -PFA composites showed a high effective permittivity, low loss, low leakage and voltage tolerance, demonstrating the capability for high energy density capacitance. Effective permittivity, of 52 (BTNO-PFA) and 42 (BTTO-PFA) for pellet nanocomposites and 32 (BTNO-PVP) and 20 (BTNO-PVP) film nanocomposites were observed at 1 MHz respectively. Voltage breakdown strengths of 2133 V/mm (BTNO) and 833 V/mm (BTTO) were demonstrated respectively (threshold 0.1 μA). Linear and non-linear dielectric behavior was studied by polarization-electric field (P-E) hysteresis measurements. Nanocomposites of BTNO-PVDF-TrFE were prepared to assess the viability of making ferroelectric nanocomposites over a range of polymer-nanoparticle volume fractions.