Dielectric and Thermal Investigations on PbNb₂O₆ in Pure Piezoelectric Phase and Pure Non-Piezoelectric Phase

Structural Characterization of Orthorhombic and Rhombohedral Lead Meta-Niobate Samples

“…11 and 12 clearly show how the NbO 6 octahedra, a common feature of Q and S samples, assemble into orthorhombic Q PN and rhombohedral S PN structures that are significantly different. The difference in the crystallographic structure makes the orthorhombic Q PN polarizable, and ferroelectric below its Curie temperature [1]. This is a piezoelectric material with potential for high temperature applications.…”

“…Atomic bonding and molecular level structure as revealed by Fourier Transform Infra-Red spectroscopy (FTIR) greatly governs the crystallographic structure, revealed by X-Ray Diffraction (XRD). Here, XRD Rietveld analysis and the detailed structure of the final products-orthorhombic PbNb 2 O 6 and rhombohedral PbNb 2 O 6 -have been carried out and presented in view of the good quality of the present samples [1,7,8].…”

“…But, to date, the best piezoelectric materials like lead-zirconate-titanate (PZT) are for near room temperature applications only, due to their relatively low Curie temperature. Certain high temperature applications in industry need materials with high Curie temperature, and lead meta-niobate (PbNb 2 O 6 ) or PN with a Curie temperature above 570 • C [1,2] is one of the attractive choices. The stable forms of PbNb 2 O 6 are [3][4][5]: rhombohedral at low temperatures like the room temperature, and tetragonal at high temperatures.…”

“…Slow-cooling (S), from the tetragonal phase, leads to S PN, the non-piezoelectric rhombohedral phase. Lead meta-niobate has not been widely studied [1][2][3][4][5][6][7], the rhombohedral phase being hardly studied. So, our present and other current work [1] are on orthorhombic as well as rhombohedral samples.…”

Dielectric Properties of RhombohedralPbNb2O6

“…Slow ( ) cooling (from temperatures like 1270 ∘ C) leads [10,11] to PNS, rhombohedral PbNb 2 O 6 , which is not ferroelectric; ruling out piezoelectric properties and piezoelectric applications. So, most R & D efforts have been concentrated on orthorhombic PbNb 2 O 6 [1][2][3][4][5][12][13][14][15][16][17][18][19][20][21].…”