Giant dielectric permittivity and high tunability in Y-doped SrTiO3 ceramics tailored by sintering atmosphere
authors Tkach, A; Okhay, O; Almeida, A; Vilarinho, PM
nationality International
journal ACTA MATERIALIA
author keywords Electroceramics; Donor doping; Polar clusters; Maxwell-Wagner interfacial polarization
keywords STRONTIUM-TITANATE CERAMICS; ELECTRICAL-CONDUCTIVITY; COLOSSAL PERMITTIVITY; ANODE MATERIALS; CACU3TI4O12; MICROSTRUCTURE; PHASE; TRANSITION; BEHAVIOR; RELAXOR
abstract Development of giant-permittivity and high-tunability dielectric materials has attracted great interest because of growing demand for smaller and faster energy-storage and electronic devices. Materials such as CaCu3Ti4O12, displaying the giant dielectric permittivity due to extrinsic Maxwell-Wagner interfacial polarization effect, have previously been reported. Ferroelectric materials possessing intrinsic ionic polarization due to a phase transition to the polar state have also been indicated to possess a high tunability of the dielectric permittivity by dc electric field. Here, a class of the giant-permittivity materials based on SrTiO3 ceramics doped with up to 1% of yttrium and their processing concept, which yields the dielectric permittivity up to similar to 209,000 at 10 kHz for nitrogen sintering atmosphere, and the relative tunability up to similar to 74% under 20 kV cm(-1) for oxygen sintering atmosphere, is reported. The high tunability is proved to be due to polar clusters created at low temperatures by off-central Y3+ ions on Sr2+ sites. The giant permittivity is explained by a coupling of the polar clusters relaxation mode with the donor substitution induced electrons at low temperatures and by the Maxwell-Wagner relaxation around room temperature. Besides the fundamental understanding, this discovery opens a new development window for high frequency and low-temperature electronic and energy-storage applications. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
publisher PERGAMON-ELSEVIER SCIENCE LTD
issn 1359-6454
isbn 1873-2453
year published 2017
volume 130
beginning page 249
ending page 260
digital object identifier (doi) 10.1016/j.actamat.2017.03.051
web of science category Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering
subject category Materials Science; Metallurgy & Metallurgical Engineering
unique article identifier WOS:000401388700022
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journal analysis (jcr 2017):
journal impact factor 6.036
5 year journal impact factor 6.174
category normalized journal impact factor percentile 92.737
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