Solid Solutions Based on Ferroelectric PbNb₂,O₆

Abstract

An X-ray and dielectric study of three series of PbNbz06-type solid solutions was carried out.The PbNbZOs-type phase was present up to the following limits : (1) (Pbl-,Bi,) (Ti,Nbz-.)Oa,Orthorhombic distortion b / a and Curie temperature decreased with increasing x. Bi4/3-Ti206 was most effective in this respect and Biz, 3-Nb206 had the least influence. The important role played by ions of different valency located on crystallographically equivalent sites is pointed out.

Phase transition behaviour and electromechanical properties of (Na1/2Bi1/2)TiO3–KNbO3lead-free piezoelectric ceramics

“…The reason is that KN incorporation reduces the extent of anisotropy of crystal structure and the ferroelectric stability weakens. The effect on Curie temperature is similar to that of KN incorporation in BaTiO 3 [15] or PbTiO 3 [16]. For the samples with x = 0.02, which is the rhombohedral symmetry at room temperature, the value of the maximum permittivity is larger than that of the hump permittivity.…”

Effects of Microstructure on the Dielectric and Piezoelectric Properties of Lead Metaniobate

“…33 Various techniques have been used to obtain dense PbNb 2 O 6 . Substitution of similar ions for lead or niobium has been studied to improve sintering characteristics and electrical properties, 34,35 and several dopants have been known to effectively improve sinterability. 36 An elaborate method by a coprecipitation process in oxalic solution is used to improve the electromechanical properties of PbNb 2 O 6 .…”

Thermal Expansion Anomaly in TTB Ferroelectrics: The Interplay between Framework Structure and Electric Polarization

“…The TTB tungstates, such as K x WO 3 (4/ mmm ), Na 0.33 WO 3 (4̅2 m ), Na 0.48 WO 3 (4/ mmm ), , and Pb 0.26 WO 3 (4/ mmm ), are centrosymmetric or nonpolar. In contrast, the TTB niobates include numerous ferroelectric materials and have been widely investigated. ,− ,− , Aside from the oxides, ferroelectricity has also been reported in a few TTB fluorides (K 3 Fe 5 F 15 , ) and oxyfluorides (Sr 2– x A 1+ x Nb 5 O 15‑ x F x , A = Na, K) . In K 3 Fe 5 F 15 [K 3 (Fe 2+ ) 3 (Fe 3+ ) 2 F 15 ], ferroelectricity and ferroelasticity were induced by charge ordering (CO) of Fe 2+ and Fe 3+ in the octahedral B sites (Figure c), , which makes K 3 Fe 5 F 15 an order–disorder-type ferroelectric.…”

“…In contrast, the TTB niobates include numerous ferroelectric materials and have been widely investigated. 13,[62][63][64][65][66][67][68][69][49][50][51]11 Aside from the oxides, ferroelectricity has also been reported in a few TTB fl u o r i d e s ( K 3 F e 5 F 1 5 3 0 , 3 1 ) and oxyfl u o r i d e s (Sr 2 − x A 1 + x Nb 5 O 1 5x F x , A = Na, K). 3 2 In K 3 Fe 5 F 1 5 [K 3 (Fe 2+ ) 3 (Fe 3+ ) 2 F 15 ], ferroelectricity and ferroelasticity were induced by charge ordering (CO) of Fe 2+ and Fe 3+ in the octahedral B sites (Figure 1c), 34,70 which makes K 3 Fe 5 F 15 an order−disorder-type ferroelectric.…”