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Structure and Microwave Dielectric Behavior of A‐Site‐Doped Sr (1−1.5 x ) Ce x TiO 3 Ceramics System
Author(s) -
Ullah Burhan,
Lei Wen,
Cao QingSong,
Zou ZhengYu,
Lan XueKai,
Wang XiaoHong,
Lu WenZhong
Publication year - 2016
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14341
Subject(s) - analytical chemistry (journal) , materials science , tetragonal crystal system , orthorhombic crystal system , temperature coefficient , dielectric , valence (chemistry) , microstructure , ceramic , ion , doping , mineralogy , crystal structure , crystallography , chemistry , metallurgy , optoelectronics , organic chemistry , chromatography , composite material
The ion valence state, phase composition, microstructure, and microwave dielectric properties of Sr (1−1.5 x ) Ce x TiO 3 ( x = 0.1–0.67, SCT) ceramics were systematically investigated. Sr (1−1.5 x ) Ce x TiO 3 ceramics were produced with gradual structural evolution from a cubic to a tetragonal and turned to an orthorhombic structure in the range of 0.1 ≤ x ≤ 0.67. Above a critical Ce proportion ( x = 0.4), microstructural changes and normal grain growth initially occurred. On the basis of chemical analysis results, the reduction of Ti 4+ ions was hastened by tetravalent ions (Ce 4+ ). By contrast, this reduction was inhibited by trivalent ions (Ce 3+ ). The observed dielectric behavior was strongly influenced by phase composition, oxygen vacancies ( V O ∙ ∙ ), and defect dipoles, namely, ( Ti ′ − V O ∙ ∙) and ( V Sr ″ − V O ∙ ∙). Temperature stable ceramics sintered at 1350°C for 3 h in air yielded an intermediate value of dielectric constant (ε r = 40), with the smallest reported value of temperature coefficient of resonant frequency (τ f = +0.9 ppm/°C), and quality factor ( Q × f = 5699 GHz) at x = 0.6.