TY - JOUR
T1 - Synthesis and effect of Ba2+ ions on the dielectric properties of the layered-perovskite KSr2NaNb4O13 ceramics
AU - Im, Mir
AU - Kim, Dong Ha
AU - Kweon, Sang Hyo
AU - Lee, Woong Hee
AU - Nahm, Sahn
N1 - Funding Information:
This work was supported by the Energy Technology Development Project (KETEP) grant funded by the Ministry of Trade, Industry and Energy, Republic of Korea (Piezoelectric Energy Harvester Development and Demonstration for scavenging Energy from Road Traffic System , project No. 20,142,020,103,970). The authors would also like thank the KU-KIST Graduate School Program of Korea University.
PY - 2018/9
Y1 - 2018/9
N2 - The 25 mol% K2O-added K(Sr2Na)Nb4O13 ceramic sintered at 1275 °C exhibited a pure and dense K(Sr2Na)Nb4O13 phase, which had four octahedral layers. Synthesis of a pure K(Sr2Na)Nb4O13 ceramic was not possible without excess K2O, due to the formation of a Na-deficient K(Sr2Na2)Nb5O16 secondary phase, because of K2O evaporation during sintering. The dielectric constant (εr) of the K(Sr2Na)Nb4O13 ceramic was 43.8 at 100 kHz, two times higher compared to the KSr2Nb3O10 ceramic, which has three octahedral layers. The increased εr can be explained by the increased number of octahedral layers. Some of the Sr2+ ions in K(Sr2Na)Nb4O13 ceramic were replaced by Ba2+ ions, which have high ionic polarizability, to further increase εr. The 25 mol% K2O-excess K(Sr0.8Ba0.2)2NaNb4O13 ceramic sintered at 1250 °C showed a high εr of 67.4 at 100 kHz, which can be explained by the increased dipole moments and distortion of the NbO6 octahedra.
AB - The 25 mol% K2O-added K(Sr2Na)Nb4O13 ceramic sintered at 1275 °C exhibited a pure and dense K(Sr2Na)Nb4O13 phase, which had four octahedral layers. Synthesis of a pure K(Sr2Na)Nb4O13 ceramic was not possible without excess K2O, due to the formation of a Na-deficient K(Sr2Na2)Nb5O16 secondary phase, because of K2O evaporation during sintering. The dielectric constant (εr) of the K(Sr2Na)Nb4O13 ceramic was 43.8 at 100 kHz, two times higher compared to the KSr2Nb3O10 ceramic, which has three octahedral layers. The increased εr can be explained by the increased number of octahedral layers. Some of the Sr2+ ions in K(Sr2Na)Nb4O13 ceramic were replaced by Ba2+ ions, which have high ionic polarizability, to further increase εr. The 25 mol% K2O-excess K(Sr0.8Ba0.2)2NaNb4O13 ceramic sintered at 1250 °C showed a high εr of 67.4 at 100 kHz, which can be explained by the increased dipole moments and distortion of the NbO6 octahedra.
KW - Dion-Jacobson (DJ) phase
KW - High-κ dielectrics
KW - Inorganic nanosheets
KW - K(SrNa)NbO compound
KW - Layered perovskite
UR - http://www.scopus.com/inward/record.url?scp=85047101189&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85047101189&partnerID=8YFLogxK
U2 - 10.1016/j.materresbull.2018.04.056
DO - 10.1016/j.materresbull.2018.04.056
M3 - Article
AN - SCOPUS:85047101189
VL - 105
SP - 246
EP - 252
JO - Materials Research Bulletin
JF - Materials Research Bulletin
SN - 0025-5408
ER -