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A High‐Temperature‐Capacitor Dielectric Based on K 0.5 Na 0.5 NbO 3 ‐Modified Bi 1/2 Na 1/2 TiO 3 – Bi 1/2 K 1/2 TiO 3
Author(s) -
Dittmer Robert,
Anton EvaMaria,
Jo Wook,
Simons Hugh,
Daniels John E.,
Hoffman Mark,
Pokorny Jan,
Reaney Ian M.,
Rödel Jürgen
Publication year - 2012
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/j.1551-2916.2012.05321.x
Subject(s) - permittivity , materials science , dielectric , analytical chemistry (journal) , raman spectroscopy , phase boundary , dielectric loss , phase (matter) , mineralogy , chemistry , optics , physics , organic chemistry , optoelectronics , chromatography
A high‐temperature dielectric, (1– x )(0.6 Bi 1/2 Na 1/2 TiO 3 –0.4 Bi 1/2 K 1/2 TiO 3 )– x K 0.5 Na 0.5 NbO 3 , off the morphotropic phase boundary of the parent matrix 0.8 Bi 1/2 Na 1/2 TiO 3 –0.2 Bi 1/2 K 1/2 TiO 3 , has been developed for application as a high‐temperature capacitor. In addition to temperature‐dependent permittivity and dielectric loss, DC conductivity and field‐dependent permittivity are reported. These properties are correlated with temperature‐dependent structure data measured at different length scales using Raman spectroscopy and neutron diffraction. It is suggested that all materials investigated are ergodic relaxors with two types of polar nanoregions providing different relaxation mechanisms. The most attractive properties for application as high‐temperature dielectrics are obtained in a material with x = 0.15 at less than 10% variation of relative permittivity of about 2100 between 54°C and 400°C.