Thin Solid Films, Vol.423, No.2, 235-242, 2003
Substitution of Nb doping on the structural, microstructural and electrical properties in PZT films
Undoped and niobium (Nb) doped Pb1-y(Zr0.54Ti0.46)(1-y)NbyO3 have been deposited by sputtering on Pt metallized silicon substrates. The niobium concentration, y, was varied from 1 to 7 at.% by I at.%. The Zr/Ti ratio was fixed to 54/46 corresponding to the Morphotropic Phase Boundary. Structural, microstructural, and electrical properties were evaluated depending on Nb content. The films (doped and undoped) present a (I I 1)-preferred orientation. The Nb doping induces an increase of the grain size and as it was observed in bulk materials the dielectric constant (epsilon(r)) and the piezoelectric coefficients (e(31) and d(33)) reach their maximum for low Nb concentration (2 at.%). The remnant and the maximum polarizations increase as the coercive field decreased slightly with the Nb concentration. The internal electric field increases with Nb content; as a result, the 'self-polarization' of the films (polarization measured without poling treatment) is enhanced with niobium substitution. In term of fatigue behavior, it was found that switching endurance characteristics are maximum for low Nb doping level.
Keywords:thin film ceramics;Nb-doped PZT materials;sputtering properties;dielectric properties;ferroelectric properties;piezoelectric properties