Dielectric Properties of Modified Lead Zinc Niobate Ceramic

Abstract

Crystal structures, dielectric properties and electrical resistivities for partially substituted lead zinc niobate [Pb(Zn1/3Nb2/3)O3] ceramic were investigated. This ceramic, sintered at 1000–1050°C, was composed mainly of perovskite phase and showed a high dielectric constant (3500–5000) and a high resistivity (approximately 1013Ω·cm) when partial substitutions of the Pb site by Ba or Sr and the (Zn1/3Nb2/3) site by Ti in the Pb(Zn1/3Nb2/3)O3 were carried out. The reason why the perovskite phase was stable in the sintered body is explained qualitatively by introducing the concepts of an electronegativity difference and a tolerance factor.

New High Temperature Morphotropic Phase Boundary Piezoelectrics Based on Bi(Me)O3–PbTiO3 Ceramics

“…8) In conjunction with ionic electronegativity, tolerance factor has been used as a guideline for a number of difficult-to-prepare Pb-based relaxor systems, such as Pb(Mg 1/3 Nb 2/3 )O 3 (t = 0.89) and Pb(Zn 1/3 Nb 2/3 )O 3 (t = 0.986) whereby the substitution of the small Pb +2 cation with a few mole% Ba +2 significantly enhanced the stability of the perovskite phase. [9][10][11] Although the existence of ferroelectricity cannot be predicted based on tolerance factor, general observations of a low symmetry distortion of the unit cell for ferroelectric perovskites with t < 1, being rhombohedral or monoclinic while those with t > 1 are tetragonal, depending on whether the ferroelectric active ions are on the A-or B-site (e.g., A = Pb +2 , Bi +3 , Cd +2 ; B = Ti +4 , Nb +5 , Ta +5 ) have been reported. 12) It has also been noted that there is a general trend of higher transition temperature in ferroelectric perovskites with decreasing 't'.…”

Development of perovskite and phase transition in lead cobalt niobate modified lead zirconate titanate system

“…Pb(Zn 1/3 Nb 2/3 )O 3 -PbTiO 3 (PZN-PT) [4,5], Pb(Zr 1/2 Ti 1/2 )O 3 -Pb(Ni 1/3 Nb 2/3 )O 3 (PZT-PNN) [6]}, excellent piezoelectric coefficients {e.g. Pb(Zn 1/3 Nb 2/3 )-O 3 -PbTiO 3 (PZN-PT) [4,5], Pb(Zr 1/2 Ti 1/2 )O 3 -Pb(Zn 1/3 Nb 2/3 )-O 3 (PZN-PZT) [7], Pb(Sc 1/3 Nb 2/3 )O 3 -PbTiO 3 (PSN-PT) [8,9]}, and high pyroelectric coefficients {e.g. Pb(Ni 1/3 -Nb 2/3 )O 3 -PbTiO 3 -PbZrO 3 (PNN-PT-PZ) [10]}.…”

Microstructural and electrical study of mixed phase of Pb(Ba1/3Nb2/3)O3

“…Usual solid-state reaction route does not stabilize the perovskite phase in these materials [1]. A number of preparation routes are tried for these materials [2][3][4][5][6][7]; however, the two-stage columbite and B-oxide route lead to stable perovskite phase.…”