resumo
The incorporation of chromium on the strontium site of the perovskite lattice of SrTiO3 ceramics and its influence on the structural, microstructural and low-frequency dielectric properties is studied in this work. Dense Sr1-1.5xCrxTiO3 (x = 0, 0.0005, 0.0010, 0.0015) ceramics are prepared from powders obtained by a sol-gel method. The lattice parameter similar to 3.906 angstrom and average grain size similar to 2.5 mu m are almost identical for all the ceramic samples under study. On the other hand, the dielectric constant increases from approximately 7000 for x = 0 to > 16 000 for x = 0.0005. Detailed investigations of the low-temperature dielectric properties show a remarkable increase of the tunability and nonlinearity of the dielectric constant as a function of dc bias field in strontium titanate ceramics modified by chromium doping but no ferroelectric or relaxor-like behaviour. These results imply the possible incorporation of small Cr amounts on the Sr site of strontium titanate ceramics and expand the tunable applications of SrTiO3-based materials.
palavras-chave
PHASE-TRANSITIONS; MICROWAVE DEVICES; SOLID-SOLUTIONS; SRTIO3; MICROSTRUCTURE; SR1-XCAXTIO3; SPECTROSCOPY; BEHAVIOR; DOPANTS; PLANAR
categoria
Physics
autores
Tkach, A; Okhay, O; Vilarinho, PM; Kholkin, AL
nossos autores
Andrei Kholkin
Investigador Jubilado
Oleksandr Tkach
Investigador Principal
Olena Okhay
Bolseiro de pós-Doutoramento
Paula Maria Lousada Silveirinha Vilarinho
Vice-Diretoragradecimentos
The authors acknowledge financial support from FEDER and the European Network of Excellence FAME under contract FP6-500159-1. OO acknowledges the FCT for financial support (SFRH/BD/19861/2004).