Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANT
La0.67LixTi1-xAlxO3 ceramics (x = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30) were synthesized with the use of Al2O3 and an aqueous solution of Al(NO3)3 as an aluminium source. In both cases, the ceramics preserve a high dielectric constant ε ~ 105. It was found that the single-pha...
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| author | Plutenko, Tetiana V'yunov, Oleg Fedorchuk, Oleksandr Yanchevskii, Oleg Torchyniuk, Pavlo |
| author_facet | Plutenko, Tetiana V'yunov, Oleg Fedorchuk, Oleksandr Yanchevskii, Oleg Torchyniuk, Pavlo |
| author_institution_txt_mv | [
{
"author": "Tetiana Plutenko",
"institution": "V.I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Sciences of Ukraine"
},
{
"author": "Oleg V'yunov",
"institution": "V. I. Vernadsky Institute of General and Inorganic Chemistry"
},
{
"author": "Oleksandr Fedorchuk",
"institution": "V.I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Sciences of Ukraine"
},
{
"author": "Oleg Yanchevskii",
"institution": "V.I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Sciences of Ukraine"
},
{
"author": "Pavlo Torchyniuk",
"institution": "V.I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Sciences of Ukraine, Palladina ave., 32\/34, Kyiv, 03142, Ukraine mob. phone. (+38099) 727-98-06"
}
] |
| author_sort | Plutenko, Tetiana |
| baseUrl_str | https://ucj.org.ua/index.php/journal/oai |
| collection | OJS |
| datestamp_date | 2026-07-22T08:23:52Z |
| description | La0.67LixTi1-xAlxO3 ceramics (x = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30) were synthesized with the use of Al2O3 and an aqueous solution of Al(NO3)3 as an aluminium source. In both cases, the ceramics preserve a high dielectric constant ε ~ 105. It was found that the single-phase La0.67LixTi1-xAlxO3 perovskite structure is formed at temperatures above 1200  C. It was shown that the use of Al(NO3)3 allows simplifying the synthesis: reduction in the sintering temperature by 20  C, Li loss and, as a result, an increase in the density of ceramics. Ceramics La0.67Li0.15Ti0.85Al0.15O3 with a maximum density higher than 85 % were sintered at about 1280 and 1300  C of with the use of Al(NO3)3 and Al2O3 respectively. Frequency spectra of imaginary parts of impedance and electrical modulus demonstrate two dispersion regions that refer to processes in the ceramic grains’ boundaries and ceramic grains. Ceramic samples synthesized using Al(NO3)3 solutions tend to exhibit higher dielectric constants than those synthesized using Al2O3. At a frequency of 100 Hz, the dielectric constant for ceramics synthesized using Al(NO3)3 aqueous solution is 70600, whereas that for ceramics synthesized using Al2O3 is 44300. Obtained materials are useful for microelectronics, energy storage and harvesting devices. |
| doi_str_mv | 10.33609/2708-129X.89.06.2023.71-78 |
| first_indexed | 2025-09-24T17:43:51Z |
| format | Article |
| fulltext |
71
UDC: 549.641.1; 537.226.1 doi: 10.33609/2708-129X.89.06.2023.71-78
Al-DOPED LANTHANUM-LITHIUM TITANATE WITH
HIGH DIELECTRIC CONSTANT
T.O. Plutenko, O.P. Fedorchuk*, O.I. V’yunov, O.Z. Yanchevskii, P.V. Torchyniuk
V.I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Sciences
of Ukraine, 32/34 Aсad. Palladin ave, 03142 Kyiv, Ukraine
e-mail: alex1377c9@gmail.com
La0.67LixTi1-xAlxO3 ceramics (x = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30) were synthesized with
the use of Al2O3 and an aqueous solution of Al(NO3)3 as an aluminium source. In both cases,
the ceramics preserve a high dielectric constant ε ~ 105. It was found that the single-phase
La0.67LixTi1-xAlxO3 perovskite structure is formed at temperatures above 1200 °C. It was shown
that the use of Al(NO3)3 allows simplifying the synthesis: reduction in the sintering tem-
perature by 20 °C, Li loss and, as a result, an increase in the density of ceramics. Ceramics
La0.67Li0.15Ti0.85Al0.15O3 with a maximum density higher than 85 % were sintered at about 1280
and 1300 °C of with the use of Al(NO3)3 and Al2O3 respectively. Frequency spectra of ima
ginary parts of impedance and electrical modulus demonstrate two dispersion regions that
refer to processes in the ceramic grains’ boundaries and ceramic grains. Ceramic samples
synthesized using Al(NO3)3 solutions tend to exhibit higher dielectric constants than those
synthesized using Al2O3. At a frequency of 100 Hz, the dielectric constant for ceramics syn-
thesized using Al(NO3)3 aqueous solution is 70600, whereas that for ceramics synthesized
using Al2O3 is 44300. Obtained materials are useful for microelectronics, energy storage and
harvesting devices.
Keywords: Li-containing, aluminium nitrate, microelectronics, perovskite, solid-state re-
action technique.
INTRODUCTION. Materials based on lithi
um-containing perovskites with a high dielec-
tric constant (ε > 1000) have been developed
for use in microelectronics to address the chal-
lenge of miniaturizing electronic circuits [1].
They are used in the field of microelectronics,
in the development of thermostable compo-
nents of electronics [1], solid energy storage
(Multi-Layer Ceramic Capacitors) [2], solar
energy [3], electrochemical devices, and deep
mining and space technology [4]. These mate-
rials are of both scientific and practical interest
due to the high effective dielectric constant re-
sulting from the relaxation of mobile lithium
ions [5]. The authors of [6, 7] investigated the
substitution of La and Ti ions by Li and Al ions
in the La2/3LixTi1-xAlxO3 system to improve its
electrical characteristics. Depending on the
sintering conditions, the resulting perovskites
can crystallize in either orthorhombic or
72 ISSN 2708-129X. Укр. хім. журн., 2023
Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANTINORGANIC CHEMISTRY
rhombohedral syngony. The La2/3LixTi1-xAlxO3
materials with orthorhombic syngony form
solid solutions in the concentration range
x = 0.15–0.30, and exhibit a high dielectric con-
stant [8]. However, there is a lack of research
on the crystal structure and dielectric proper-
ties of this material at concentration ranges of
x less than 0.15 and more than 0.3.
The conventional method of preparing
powders for ceramic material production in-
volves roasting a mechanically crushed mix-
ture of metal oxides and carbonates in specific
proportions [9]. However, this process intro-
duces pollutants from abrasive materials dur-
ing grinding, which negatively affect dielectric
properties. The solid-state reaction, a diffu-
sion-controlled process, requires a uniform
distribution of each substance to produce a
fully reacted and homogeneous product. The
prolonged calcination at high temperatures
and precise atmospheric control needed for
the mechanically ground mixture results in the
loss of volatile components, such as lithium.
Additionally, achieving good density requires
very high sintering temperatures.
Numerous studies have been dedicated to
the development of La2/3−xLi3xTiO3 LLTO-based
materials; however, they typically focus solely
on the properties of the resulting perovskites,
neglecting the study of chemical transforma-
tions that occur during synthesis. As a result,
further enhancement of synthesis and material
characteristics is impeded. The present study
represents a pivotal point in investigating the
chemical transformations that occur during
the synthesis of LLTO-based perovskites and
aims to improve the synthesis process for fur-
ther research.
The goal of this study is to explore phase for-
mation during the synthesis of La0.67LixTi1-xAlxO3-
based solid solutions using the solid-state reac-
tion technique with the incorporation of Al2O3,
as well as to reduce sintering temperature and
minimize Li loss during solid-state synthesis.
The use of an aqueous solution of Al(NO3)3
as an aluminum source should decrease the
sintering temperature while ensuring a more
uniform distribution of aluminum in the ma-
terial, thus preventing the accumulation of Al
in localized conglomerates that can occur with
solid Al2O3.
EXPERIMENT AND DISCUSSION OF
THE RESULT. The following initial reagents
were used for the synthesis of La0.67LixTi1‑xAlxO3
(x = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30) solid solu-
tions: stoichiometric amounts of dried Li2CO3
(Merck 99.99%), La2O3 (Aldrich 99.99%), TiO2
(Aldrich 99%), and Al2O3 (Merck 99.99%) or
an aqueous solution of Al(NO3)3 as the source of
aluminium. Li2CO3 was dried at 300 °C, La2O3
at 800° C, Al2O3 and TiO2 at 600 °C. Mixed
powders were ground in an agate mortar with
isopropyl alcohol (or alcohol and the solu-
tion of Al(NO3)3) and calcined in air for 4 h at
1200 °C.
X-ray powder diffraction was performed
using a DRON-4-07 diffractometer (Cu Kα
radiation, 40 kV, 20 mA) for the analysis of
phases formed during the synthesis. The unit
cell parameters of the samples were calculated
using the Le Bail procedure [8] and the Full-
Prof software. In order to determine interme-
diate phases during synthesis, isothermal heat
treatment was carried out in the temperature
range from room temperature (RT) to 1200 °C
during 2 h (crucibles with the diameter D =
3 cm and height h = 2 cm). The change in the
phase composition was studied in the tempera-
ture range 20–1200 ºC by method X-ray phase
diffraction (XRD) analysis using DRON-4-07
73https://ucj.org.ua
T.O. Plutenko, O.P. Fedorchuk, O.I. V’yunov, O.Z. Yanchevskii, P.V. Torchyniuk UCJ № 06 / Vol. 89
CuKα-radiation; 40 kV, 20 mA). SiO2 and
Al2O3 were used as external standards (for 2Θ
and intensity).
The heat treatment of powders was car-
ried out. After grinding, the powders were
compressed into tablets under the pressure of
500 kg/cm2 (50 MPa). The materials sintered
in the temperature range of 1270–1320 °C de-
pending on the Li and Al contents (the heating
rate was 200 °/h). The tablets were sintered for
6 hours and cooled to the room temperature at
a cooling rate of 200 °/h.
To carry out the measurements of the dielec
tric properties metal electrodes were applied
on the end faces of sintered cylindrical samples
with a diameter of 8 mm and a thickness of
2 mm. Impedance spectroscopy measurements
were performed using a 1260 Impedance / Gain
phase Analyzer (Solartron Analytical).
It was shown that single-phase
La0.67LixTi1-xAlxO3 perovskites were formed at
temperatures above 1200 °C (Fig. 1.). Using
XRPD analysis intermediate phases during so
lid-state reaction technique were determined.
Fig. 1. XRPD patterns for La0.67Li0.15Ti0.85Al0.15O3 solid solution at different
calcination temperatures. Intermediate phases are marked with symbols.
The processes of mechanical mixing and adsorption of moisture from the air by
lanthanum oxide at room temperature lead to the formation of hydroxide:
La2O3 + 2H2O
20−300 °C
→ 2 La(OH)3 (1)
Increase in temperature to 300–400 °C leads to reactions of lanthanum hydroxide and
carbon dioxide from the air, lanthanum dioxycarbonate forms:
2 La(OH)3 + CO2
300−400 °C
→ La2O2CO3 +3 H2O (2)
In the temperature range of 500-600 °C lithium carbonate interacts with titanium
oxide:
Li2CO3 + TiO2
500−600 °C
→ Li2TiO3 + CO2↑ (3)
Lanthanum dioxycarbonate decomposes and lanthanum titanate interacts with
titanium oxide at a temperature of about 900 °C. Di- and trititanates forms
La2O2CO3
600−900 °C
→ La2O3 + CO2↑ (4)
Li2TiO3 + TiO2
650−900 °C
→ Li2Ti2O5 (5)
Li2Ti2O5 + TiO2
750−900 °C
→ Li2Ti3O7 (6)
Lanthanum and titanium oxides interact in the temperature range of 800-1000 °C to
form lanthanum dititanate:
La2O3 + 2TiO2
800−1000 °C
→ La2Ti2O7 (7)
At temperatures above 1000 °C lanthanum aluminate and lanthanum titanate
perovskites form:
La2Ti2O7+ TiO2
1000−1100 °C
→ 3La2/3TiO3 (8)
Fig. 1. XRPD patterns for La0.67Li0.15Ti0.85Al0.15O3
solid solution at different calcination tempe
ratures. Intermediate phases are marked with
symbols.
The processes of mechanical mixing and
adsorption of moisture from the air by lan-
thanum oxide at room temperature lead to the
formation of hydroxide:
La2O3 + 2H2O 20–300 °С 2 La(OH)3 (1)
Increase in temperature to 300–400 °C leads
to reactions of lanthanum hydroxide and car-
bon dioxide from the air, lanthanum dioxycar-
bonate forms:
2 La(OH)3 + CO2
300–400 °С
La2O2CO3 +3 H2O
(2)
In the temperature range of 500-600 °C lithi
um carbonate interacts with titanium oxide:
Li2CO3 + TiO2
500–600 °С Li2TiO3 + CO2↑ (3)
Lanthanum dioxycarbonate decomposes
and lanthanum titanate interacts with titanium
oxide at a temperature of about 900 °C. Di- and
trititanates forms
74 ISSN 2708-129X. Укр. хім. журн., 2023
Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANTINORGANIC CHEMISTRY
La2O2CO3
600–900 °С
La2O3 + CO2↑ (4)
Li2TiO3 + TiO2
650–900 °С
Li2Ti2O5 (5)
Li2Ti2O5 + TiO2
750–900 °С
Li2Ti3O7 (6)
Lanthanum and titanium oxides interact in
the temperature range of 800–1000 °C to form
lanthanum dititanate:
La2O3 + 2TiO2
800–1000 °С La2Ti2O7 (7)
At temperatures above 1000 °C lanthanum
aluminate and lanthanum titanate perovskites
form:
La2Ti2O7+ TiO2
1000–1100 °С
3La2/3TiO3 (8)
La2O3 + Al2O3
1000–1100 °С
2LaAlO3 (9)
Onwards lithium-lanthanum titanate
and lanthanum titanate-aluminate form at
1100–1200 °C:
(1-1,5y) La2/3TiO3 + 1,5y Li2TiO3
1100–1200 °С
1100–1200 °С La(2/3-y)Li3yTiO3 (10)
(1-3z) La2/3TiO3 + 3z LaAlO3
1100–1200 °С
1100–1200 °С La(2/3+z)Ti(1-3z)Al3zO3 (11)
La2/3LixTi1-xAlxO3 solid solutions were ob-
tained by the interaction of the phases ob-
tained by reactions (10) and (11).
La2O3 + Al2O3
1000−1100 °C
→ 2LaAlO3 (9)
Onwards lithium-lanthanum titanate and lanthanum titanate-aluminate
form at 1100–1200 °C:
(1-1,5y) La2/3TiO3 + 1,5y Li2TiO3
1100−1200 °C
→ La(2/3-y)Li3yTiO3
(10)
(1-3z) La2/3TiO3 + 3z LaAlO3
1100−1200 °C
→ La(2/3+z)Ti(1-3z)Al3zO3 (11)
La2/3LixTi1-xAlxO3 solid solutions were obtained by the interaction of the phases
obtained by reactions (10) and (11).
zLa(2/3-y)Li3yTiO3+yLa(2/3+z)Ti(1-3z)Al3zO3
1100−1200 ℃
→ (z+y)La2/3Li3yz/y+zTi1-
(3yz/y+z)Al3yz/y+zO3
→(z+y) La2/3LixTi1-xAlxO3,where x = 3yz/(y + z)
(12)
The unit cell parameters were determined from the XRPD patterns using a rapid
whole-pattern profile-matching Le Bail procedure. La0.67LixTi1-xAlxO3 (where 0.15 ≤ x ≤
0.3) solid solutions synthesized with the use of Al2O3 and Al(NO3)3 aqueous solution
materials have a rhombohedral perovskite-related structure (space group R-3c, № 167).
Fig. 2 shows the dependencies of the relative density of ceramics on the sintering
temperature at x = 0.15. For La0.67Li0.15Ti0.85Al0.15O3 synthesized using the solution of
Al(NO3)3 as the aluminium source, the relative density of ceramics is higher and is achieved
at lower temperatures compared to the synthesis using Al2O3. The maximum density is 89 %
and 87 % for the use of Al(NO3)3 and Al2O3 respectively. Dependencies have maxima at
about 1280 and 1300 °C. Higher porosity of materials at high sintering temperatures can be
associated with Li loss.
Fig. 2. Dependencies of relative density on sintering temperature for
La0.67Li0.15Ti0.85Al0.15O3 ceramic samples at x = 0.15 synthesized using Al2O3 and an
aqueous solution of Al(NO3)3 as the aluminium source.
Sintering temperatures depending on the x content in ceramic samples are presented
in Fig. 3. Temperatures rise with increasing Al content. The use of Al(NO3)3 aqueous
solution instead of Al2O3 leads to a decrease in the sintering temperature. The decrease is
18–24 C.
zLa(2/3-y)Li3yTiO3+yLa(2/3+z)Ti(1-3z)Al3zO3
1100–1200 °С
(z+y)La2/3Li3yz/y+zTi1-(3yz/y+z)Al3yz/y+zO3 →
→ (z+y) La2/3LixTi1-xAlxO3,where x = 3yz/(y + z) (12)
The unit cell parameters were deter-
mined from the XRPD patterns using a rapid
whole-pattern profile-matching Le Bail pro-
cedure. La0.67LixTi1-xAlxO3 (where 0.15 ≤ x ≤
0.3) solid solutions synthesized with the use
of Al2O3 and Al(NO3)3 aqueous solution ma-
terials have a rhombohedral perovskite-related
structure (space group R-3c, № 167).
Fig. 2 shows the dependencies of the rela-
tive density of ceramics on the sintering tem-
perature at x = 0.15. For La0.67Li0.15Ti0.85Al0.15O3
synthesized using the solution of Al(NO3)3 as
the aluminium source, the relative density of
ceramics is higher and is achieved at lower
temperatures compared to the synthesis using
Al2O3. The maximum density is 89 % and 87 %
for the use of Al(NO3)3 and Al2O3 respectively.
Dependencies have maxima at about 1280 and
1300 °C. Higher porosity of materials at high
sintering temperatures can be associated with
Li loss.
Fig. 2. Dependencies of relative density on sin-
tering temperature for La0.67Li0.15Ti0.85Al0.15O3 ce-
ramic samples at x = 0.15 synthesized using Al2O3
and an aqueous solution of Al(NO3)3 as the alu-
minium source.
Sintering temperatures depending on the
x content in ceramic samples are presented in
75https://ucj.org.ua
T.O. Plutenko, O.P. Fedorchuk, O.I. V’yunov, O.Z. Yanchevskii, P.V. Torchyniuk UCJ № 06 / Vol. 89
Fig. 3. Temperatures rise with increasing Al
content. The use of Al(NO3)3 aqueous solution
instead of Al2O3 leads to a decrease in the sin-
tering temperature. The decrease is 18–24 °C.
Fig. 3. Dependencies of sintering temperatures
on x content for La0.67LixTi1-xAlxO3ceramic samples
synthesized with the use of Al(NO3)3 aqueous solu-
tion and Al2O3.
Using impedance spectroscopy there are
three semicircles on the complex impedance dia
gram at room temperature for La0.67LixTi1-xAlxO3
ceramic samples synthesized with the use of
Al(NO3)3. Three semicircles in the Cole-Cole
plots show three relaxation mechanisms, which
may be attributed to grain, grain boundary,
and electrode polarization. Frequency spectra
of imaginary parts of impedance and electrical
modulus also demonstrate three dispersion re-
gions (Fig. 4), covering the frequency band at
least up to 10 MHz. The low-frequency region
(up to 10 Hz) refers to processes in the sample/
electrode area, the middle-frequency area (up
to 1 kHz) refers to processes within the ceramic
grains’ boundaries, and the high-frequency re-
gion refers to the relaxation of charge carriers in
ceramic grains [10].
Fig. 4. Frequency spectra of imaginary part
of impedance and electrical modulus, for
La0.67LixTi1-xAlxO3 at x = 0.15 and x = 0.20 for ce-
ramic samples, synthesized using aqueous solution
of Al(NO3)3.
It can be noted, that the maximum value of
the electrical modulus slightly increased after
increasing the Al content for both regions.
Dielectric constants spectra for La0.67Lix-
Ti1-xAlxO3 at x = 0.20 were determined (Fig.
5). Regardless of the synthesis method ceramic
samples demonstrate high values of dielectric
constant. The dielectric constant of the ceram-
ics synthesized using Al(NO3)3 solutions is
generally higher. At the frequency of 100 Hz
dielectric constant is 70600 and 44300 with the
use of Al(NO3)3 aqueous solution and Al2O3
respectively.
A notable feature of the obtained spectra is
the presence of a flat region, which will deter-
mine the operating band of the microelectro
nics components based on the presented ce-
ramics. Bandwidth (± 15 % of ε’) is 256 and
764 Hz for the ceramics synthesized using
Al(NO3)3 and Al2O3, respectively.
Fig. 3. Dependencies of sintering temperatures on x content for La0.67LixTi1-
xAlxO3ceramic samples synthesized with the use of Al(NO3)3 aqueous solution and Al2O3.
Using impedance spectroscopy there are three semicircles on the complex impedance
diagram at room temperature for La0.67LixTi1-xAlxO3 ceramic samples synthesized with the
use of Al(NO3)3. Three semicircles in the Cole-Cole plots show three relaxation
mechanisms, which may be attributed to grain, grain boundary, and electrode polarization.
Frequency spectra of imaginary parts of impedance and electrical modulus also demonstrate
three dispersion regions (Fig. 4), covering the frequency band at least up to 10 MHz. The
low-frequency region (up to 10 Hz) refers to processes in the sample/electrode area, the
middle-frequency area (up to 1 kHz) refers to processes within the ceramic grains’
boundaries, and the high-frequency region refers to the relaxation of charge carriers in
ceramic grains [10].
Fig. 4. Frequency spectra of imaginary part of impedance and electrical modulus, for
La0.67LixTi1-xAlxO3 at x = 0.15 and x = 0.20 for ceramic samples, synthesized using aqueous
solution of Al(NO3)3.
It can be noted, that the maximum value of the electrical modulus slightly increased
after increasing the Al content for both regions.
Dielectric constants spectra for La0.67LixTi1-xAlxO3 at x = 0.20 were determined (Fig.
5). Regardless of the synthesis method ceramic samples demonstrate high values of
dielectric constant. The dielectric constant of the ceramics synthesized using Al(NO3)3
Fig. 3. Dependencies of sintering temperatures on x content for La0.67LixTi1-
xAlxO3ceramic samples synthesized with the use of Al(NO3)3 aqueous solution and Al2O3.
Using impedance spectroscopy there are three semicircles on the complex impedance
diagram at room temperature for La0.67LixTi1-xAlxO3 ceramic samples synthesized with the
use of Al(NO3)3. Three semicircles in the Cole-Cole plots show three relaxation
mechanisms, which may be attributed to grain, grain boundary, and electrode polarization.
Frequency spectra of imaginary parts of impedance and electrical modulus also demonstrate
three dispersion regions (Fig. 4), covering the frequency band at least up to 10 MHz. The
low-frequency region (up to 10 Hz) refers to processes in the sample/electrode area, the
middle-frequency area (up to 1 kHz) refers to processes within the ceramic grains’
boundaries, and the high-frequency region refers to the relaxation of charge carriers in
ceramic grains [10].
Fig. 4. Frequency spectra of imaginary part of impedance and electrical modulus, for
La0.67LixTi1-xAlxO3 at x = 0.15 and x = 0.20 for ceramic samples, synthesized using aqueous
solution of Al(NO3)3.
It can be noted, that the maximum value of the electrical modulus slightly increased
after increasing the Al content for both regions.
Dielectric constants spectra for La0.67LixTi1-xAlxO3 at x = 0.20 were determined (Fig.
5). Regardless of the synthesis method ceramic samples demonstrate high values of
dielectric constant. The dielectric constant of the ceramics synthesized using Al(NO3)3
76 ISSN 2708-129X. Укр. хім. журн., 2023
Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANTINORGANIC CHEMISTRY
Fig. 5. Spectra of dielectric constant real parts
for the La0.67LixTi1-xAlxO3 ceramics at x = 0.20 syn-
thesized using Al2O3 and Al(NO3)3 aqueous solu-
tions as aluminium sources.
CONCLUSIONS. La0.67LixTi1-xAlxO3 cera
mics were synthesized by solid-state reaction
technique with the use of Al2O3 and the aque-
ous solution of Al(NO3)3 as a source of alu-
minium. It was shown that intermediate phas-
es during the solid-state reaction technique
were La(OH)3, La2O2CO3, Li2TiO3, Li2Ti2O5,
Li2Ti3O7 and La2Ti2O7. It was found, that the
use of the Al(NO3)3 solution allows to reduce
the sintering temperature, to extend the opera-
tion time of sintering furnaces, reduces the loss
of volatile elements and slightly increases the
dielectric constant of the ceramic material. Di-
electric constant spectra have a flat region with
a width of 256 and 764 Hz for the use of Al2O3
and Al(NO3)3 respectively.
Relaxation processes within the ceramic
grains boundaries and the ceramic grains de-
termine the dielectric properties of La0.67Lix-
Ti1-xAlxO3 ceramics according to the three ob-
served regions on the spectra of electric mo
dulus and impedance.
DECLARATION OF COMPETING INTE
REST. The authors declare that they have no
known competing financial interests or per-
sonal relationships that could have appeared to
influence the work reported in this paper.
ACKNOWLEDGEMENTS. The work
was carried out with the support of
the National Academy of Sciences of
Ukraine as part of the project "Synthesis
and research of nanoscale functional materi-
als for energy-generating and energy-saving
systems" (registration number 0123U103024).
The authors express their gratitude to the
Armed Forces of Ukraine for providing secu-
rity to perform this work. This work has be-
come possible only because of the resilience
and courage of the Ukrainian Army.
ТИТАНАТ ЛАНТАНУ-ЛІТІЮ, ЛЕГОВАНИЙ
АЛЮМІНІЄМ, ЩО ХАРАКТЕРИЗУЄТЬСЯ
ВИСОКОЮ ДІЕЛЕКТРИЧНОЮ КОНСТАНТОЮ
Т. О. Плутенко, О. П. Федорчук*,
О. І. В’юнов, О. З. Янчевський,
П. В. Торчинюк.
Інститут загальної та неорганічної хімії
ім. В. І. Вернадського НАН України,
просп. Акад. Палладіна 32/34, Київ 03142,
Україна
* e-mail: alex1377c9@gmail.com
Керамічні матеріали на основі
La0,67LixTi1-xAlxO3 було синтезовано методом
твердофазних реакцій з використанням
оксиду Al2O3 та нітрату алюмінію Al(NO3)3.
В обох випадках кераміка характеризується
solutions is generally higher. At the frequency of 100 Hz dielectric constant is 70600 and
44300 with the use of Al(NO3)3 aqueous solution and Al2O3 respectively.
Fig. 5. Spectra of dielectric constant real parts for the La0.67LixTi1-xAlxO3 ceramics at
x = 0.20 synthesized using Al2O3 and Al(NO3)3 aqueous solutions as aluminium sources.
A notable feature of the obtained spectra is the presence of a flat region, which will
determine the operating band of the microelectronics components based on the presented
ceramics. Bandwidth (± 15 % of ε’) is 256 and 764 Hz for the ceramics synthesized using
Al(NO3)3 and Al2O3, respectively.
CONCLUSIONS. La0.67LixTi1-xAlxO3 ceramics were synthesized by solid-state reaction
technique with the use of Al2O3 and the aqueous solution of Al(NO3)3 as a source of aluminium. It
was shown that intermediate phases during the solid-state reaction technique were La(OH)3,
La2O2CO3, Li2TiO3, Li2Ti2O5, Li2Ti3O7 and La2Ti2O7. It was found, that the use of the Al(NO3)3
solution allows to reduce the sintering temperature, to extend the operation time of sintering
furnaces, reduces the loss of volatile elements and slightly increases the dielectric constant of the
ceramic material. Dielectric constant spectra have a flat region with a width of 256 and 764 Hz for
the use of Al2O3 and Al(NO3)3 respectively.
Relaxation processes within the ceramic grains boundaries and the ceramic grains determine
the dielectric properties of La0.67LixTi1-xAlxO3 ceramics according to the three observed regions on
the spectra of electric modulus and impedance.
DECLARATION OF COMPETING INTEREST. The authors declare that they have
no known competing financial interests or personal relationships that could have appeared to
influence the work reported in this paper.
ACKNOWLEDGEMENTS. The work was carried out with the support of the National
Academy of Sciences of Ukraine as part of the project "Synthesis and research of nanoscale
functional materials for energy-generating and energy-saving systems" (registration number
0123U103024). The authors express their gratitude to the Armed Forces of Ukraine for providing
security to perform this work. This work has become possible only because of the resilience and
courage of the Ukrainian Army.
ТИТАНАТ ЛАНТАНУ-ЛІТІЮ, ЛЕГОВАНИЙ АЛЮМІНІЄМ, ЩО ХАРАКТЕРИЗУЄТЬСЯ
ВИСОКОЮ ДІЕЛЕКТРИЧНОЮ КОНСТАНТОЮ
Т. О. Плутенко, О. П. Федорчук*, О. І. В’юнов, О. З. Янчевський, А. Г. Білоус
/,.
77https://ucj.org.ua
T.O. Plutenko, O.P. Fedorchuk, O.I. V’yunov, O.Z. Yanchevskii, P.V. Torchyniuk UCJ № 06 / Vol. 89
високими значеннями діелектричної про-
никності ε ~ 105. Встановлено, що за тем-
ператури понад 1200 °С утворюється одно-
фазний твердий розчин La0,67LixTi1-xAlxO3 зі
структурою перовськіту. Використовуючи
рентгенофазовий аналіз, було встановлено
фазові перетворення, які відбуваються під
час твердофазного синтезу. Показано, що
проміжними фазами під час твердофазно-
го синтезу були La(OH)3, La2O2CO3, Li2TiO3,
Li2Ti2O5, Li2Ti3O7 та La2Ti2O7. Використання
як вихідного реагенту нітрату алюмінію
дозволяє спростити технологію синтезу,
знизити температури спікання, втрати лет-
ких компонентів та збільшити щільність
кераміки порівняно з матеріалами, синте-
зованими з використанням оксиду алю-
мінію. Було показано, що тверді розчини
La0.67Li0.15Ti0.85Al0.15O3, синтезовані з вико-
ристанням оксиду та нітрату алюмінію як
вихідних реагентів, характеризуються мак-
симальною щільністю керамічних зразків
за температур 1280 і 1300 °C відповідно.
Матеріали, отримані з використанням ніт
рату алюмінію, характеризуються вищим
значенням діелектричної проникності та
ширшим частотним діапазоном, де зміна
діелектричної проникності не перевищує
15 % порівняно з матеріалами, що отримані
з використанням оксиду алюмінію. Одер-
жані матеріали можуть бути перспектив-
ними для використання їх у мікроелектро-
ніці, пристроях накопичення та збирання
енергії.
Ключові слова: літій-вмісний, нітрат
алюмінію, мікроелектроніка, перовськіт,
твердофазний синтез.
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Стаття надійшла 12.07.2023.
|
| id | oai:ojs2.1444248.nisspano.web.hosting-test.net:article-555 |
| institution | Ukrainian Chemistry Journal |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-07-23T01:10:14Z |
| publishDate | 2023 |
| publisher | V.I.Vernadsky Institute of General and Inorganic Chemistry |
| record_format | ojs |
| resource_txt_mv | ucjorgua/3d/daf6e242d509f77ab5cc820e31e9053d.pdf |
| spelling | oai:ojs2.1444248.nisspano.web.hosting-test.net:article-5552026-07-22T08:23:52Z Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANT Plutenko, Tetiana V'yunov, Oleg Fedorchuk, Oleksandr Yanchevskii, Oleg Torchyniuk, Pavlo Li-containing, aluminium nitrate, microelectronics, perovskite, solid-state reaction technique. La0.67LixTi1-xAlxO3 ceramics (x = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30) were synthesized with the use of Al2O3 and an aqueous solution of Al(NO3)3 as an aluminium source. In both cases, the ceramics preserve a high dielectric constant ε ~ 105. It was found that the single-phase La0.67LixTi1-xAlxO3 perovskite structure is formed at temperatures above 1200  C. It was shown that the use of Al(NO3)3 allows simplifying the synthesis: reduction in the sintering temperature by 20  C, Li loss and, as a result, an increase in the density of ceramics. Ceramics La0.67Li0.15Ti0.85Al0.15O3 with a maximum density higher than 85 % were sintered at about 1280 and 1300  C of with the use of Al(NO3)3 and Al2O3 respectively. Frequency spectra of imaginary parts of impedance and electrical modulus demonstrate two dispersion regions that refer to processes in the ceramic grains’ boundaries and ceramic grains. Ceramic samples synthesized using Al(NO3)3 solutions tend to exhibit higher dielectric constants than those synthesized using Al2O3. At a frequency of 100 Hz, the dielectric constant for ceramics synthesized using Al(NO3)3 aqueous solution is 70600, whereas that for ceramics synthesized using Al2O3 is 44300. Obtained materials are useful for microelectronics, energy storage and harvesting devices. V.I.Vernadsky Institute of General and Inorganic Chemistry 2023-07-28 Article Article Inorganic Chemistry Неорганическая химия Неорганічна хімія application/pdf https://ucj.org.ua/index.php/journal/article/view/555 10.33609/2708-129X.89.06.2023.71-78 Ukrainian Chemistry Journal; Vol. 89 No. 6 (2023): Ukrainian Chemistry Journal; 71-78 Украинский химический журнал; ##issue.vol## 89 ##issue.no## 6 (2023): Ukrainian Chemistry Journal; 71-78 Український хімічний журнал; Том 89 № 6 (2023): Ukrainian Chemistry Journal; 71-78 2708-129X 2708-1281 en https://ucj.org.ua/index.php/journal/article/view/555/285 Copyright (c) 2023 Tetiana Plutenko, Oleg V'yunov, Oleksandr Fedorchuk, Oleg Yanchevskii, Pavlo Torchyniuk https://creativecommons.org/licenses/by-nc/4.0 |
| spellingShingle | Plutenko, Tetiana V'yunov, Oleg Fedorchuk, Oleksandr Yanchevskii, Oleg Torchyniuk, Pavlo Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANT |
| title | Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANT |
| title_full | Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANT |
| title_fullStr | Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANT |
| title_full_unstemmed | Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANT |
| title_short | Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANT |
| title_sort | al-doped lanthanum-lithium titanate with high dielectric constant |
| topic_facet | Li-containing aluminium nitrate microelectronics perovskite solid-state reaction technique. |
| url | https://ucj.org.ua/index.php/journal/article/view/555 |
| work_keys_str_mv | AT plutenkotetiana aldopedlanthanumlithiumtitanatewithhighdielectricconstant AT vyunovoleg aldopedlanthanumlithiumtitanatewithhighdielectricconstant AT fedorchukoleksandr aldopedlanthanumlithiumtitanatewithhighdielectricconstant AT yanchevskiioleg aldopedlanthanumlithiumtitanatewithhighdielectricconstant AT torchyniukpavlo aldopedlanthanumlithiumtitanatewithhighdielectricconstant |