| Abstract |
Giant dielectric properties of materials have widely been reported in recent years. However, a simultaneously
low dielectric loss tangent (tand) and high dielectric permittivity ( 3
0) with a low temperature
coefficient (D 3
0(T)/ 3
0
RT) have been very difficult to achieve. In this work, high performance of giant
dielectric properties were achieved in rutileeTiO2 ceramics by coedoping with acceptoreSc3þ and donor
eNb5þ ions. The important role of the former dopant was to capture free electrons at internal insulating
layers, playing as an acceptor. The latter dopant was used to produce free electrons. Ceramics that were
10% (Sc3þþNb5þ) coedoped TiO2 (10%ScNTO) exhibited very low tandz0.016e0.035 and high 3
0z103
e104 values. By optimizing the sintering conditions, excellent temperature stability of 3
0 at 1 kHz with
D 3
0(T)/ 3
0
RT < ±15% was obtained over a wide temperature range, meeting the requirement for use in X8R
capacitors. Furthermore, the dielectric properties were slightly dependent on applied DC bias. Impedance
spectroscopy analysis revealed that the ScNTO ceramics were electrically heterogeneous, consisting of
semiconducting grains and very high insulating layers. The high-performance giant-dielectric properties
of ScNTO ceramics were attributed to interfacial polarization at insulating layers with very high resistivity
and large activation energy. |
Publication
Journal Publication
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