Charge‐Compensating Defect in Ceria‐Doped Strontium Barium Niobate by Electron Energy‐Loss Spectroscopy and X‐ray Photoelectron Spectroscopy

Abstract

Undoped and CeO2‐doped Sr0.5Ba0.5Nb2O6 (SBN) powders were synthesized using the solid‐state reaction method. The lattice parameters of undoped and CeO2‐doped SBN were evaluated using X‐ray diffractometry. The valence state of the cerium ion in Ce‐doped SBN was identified using X‐ray photoelectron spectroscopy (XPS), and the valence of 3+ was confirmed. The charge‐compensated defect of the cerium doping in SBN ceramics, i.e., excessive oxygen ions occupying the vacant O(4) or O(5) site, was further evidenced using electron energy‐loss spectroscopy (EELS) and XPS. The relationships of charge‐compensated defect, structure, binding energy, and temperature of the maximum of the relative permittivity (Tm) were discussed.

Effects of Rare‐Earth Dopants on the Ferroelectric and Pyroelectric Properties of Strontium Barium Niobate Ceramics

“…The compositions were described as either (Sr 1− x Ba x ) 1−3 y /2 R y Nb 2 O 6 14 or Sr 1− x Ba x Nb 2 O 6 :R, 15 where R represents the RE element with a valence state of +3. Because the RE ions tend to occupy the Sr 2+ or Ba 2+ sites of the SBN unit cell and the radius of RE ions is smaller than or comparable with that of Sr 2+ ions, 9–10 we believe that the RE ions might occupy the smaller A1 sites in the unit cell (replacing the Sr ions). Thus, we define the chemical formula as (Sr x −3 y /2 R y )Ba 1− x Nb 2 O 6 .…”

“…Indeed, rare‐earth (RE) elements are well known for their capabilities in modifying the physical properties of ferroelectric materials, such as La‐doped Pb(Zr x Ti 1− x )O 3 8 . Nevertheless, most of these studies were confined in single crystals 6,7,9–13 . Through these studies, researchers demonstrated that doping with RE ions, as compared with changing the Sr/Ba ratio, is far more efficient in modifying the physical properties of SBN 9,13 .…”