Electrical Conduction of Ba(Ti
at High Temperatures
and XIAO-MING CHEN
1.—School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710119,
People’s Republic of China. 2.—e-mail: email@example.com
ceramics with dense microstructure have
been synthesized by a solid-state reaction method, and their electrical con-
duction investigated by broadband electrical impedance spectroscopy at fre-
quencies from 0.05 Hz to 3 9 10
Hz and temperatures from 200°C to 400°C.
Compared with BaTiO
, the real part of the permittivity and the phase-
transition temperature of Ba(Ti
decreased. Relaxation peaks
appeared in the curves of the imaginary part of the permittivity as a function
of frequency. With increase in frequency, the peaks gradually shifted towards
higher frequency and their height increased. Conductivity was closely related
to frequency and temperature. Frequency-dependent conductivity was ana-
lyzed using the Jonscher double power law. Compared with BaTO
exhibited high impedance at given frequency and tem-
perature. Impedance Cole–Cole plots displayed two semicircles, which could
be well ﬁt using two parallel RC equivalent circuit models. The conductivity
activation energy was found to be around 1 eV. For Ba(Ti
electrical modulus curve versus frequency displayed two peaks.
Key words: Electrical ceramics, impedance analysis, electrical conduction,
Materials based on barium titanate (BaTiO
are widely used in electronic devices.
rhombohedral, orthorhombic, tetragonal, and cubic
phases at temperatures of T < À90°C, À 90°C < T <
5°C, 5°C < T < 120°C, and T > 120°C, respec-
Various elements have been doped into BT
to improve its electrical properties.
It is known
that transition-metal ions, such as Co
, preferentially substitute Ti
ions in BT.
Such substitution results in formation of oxygen
vacancies owing to charge compensation.
case, the oxygen vacancy concentration is usually
higher than that in pristine or donor-doped BT.
effects of oxygen vacancies on the electrical proper-
ties of BT-based materials have been widely investi-
Among these materials, a giant
recoverable electrostrain effect was reported in aged
Fe-doped BT single crystals.
materials have also been suggested for use in spin-
reported the dielectric
and ferroelectric properties of BaTi
ceramics. Most such studies have mainly focused on
the electrical properties of BT-based materials in
Above the Curie tempera-
), BT-based materials also exhibit anomalous
In this study, the electrical
conduction of Fe
-doped BT ceramics was investi-
gated by broadband dielectric spectrometry. The
conductivity, impedance, and modulus of BT and
-doped BT ceramics were studied and compared.
(x = 0 and 0.01, denoted as BT and
BTF, respectively) ceramics were synthesized by a
solid-state reaction method using raw powders of
(purity > 99%), BaCO
(purity > 99%), and
(purity > 99%). After drying, the powders
(Received September 4, 2017; accepted February 23, 2018;
published online March 9, 2018)
Journal of ELECTRONIC MATERIALS, Vol. 47, No. 7, 2018
2018 The Minerals, Metals & Materials Society