Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4
The a.c. electrical response of LixNa₁₋xNbO₃ (LNN) solid solution in low frequency range (100 Hz–20 kHz) has been analysed as a function of temperature (300 K–750 K). A complex picture of the dependence of the studied properties on the chemical composition has been obtained. The data indicate the pr...
Збережено в:
| Дата: | 1999 |
|---|---|
| Автори: | , , , |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Інститут фізики конденсованих систем НАН України
1999
|
| Назва видання: | Condensed Matter Physics |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/121017 |
| Теги: |
Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4 / W. Bak, B. Garbarz, W. Smiga, C. Kus // Condensed Matter Physics. — 1999. — Т. 2, № 4(20). — С. 727-730. — Бібліогр.: 8 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
irk-123456789-121017 |
|---|---|
| record_format |
dspace |
| spelling |
irk-123456789-1210172017-06-14T03:05:53Z Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4 Bak, W. Garbarz, B. Smiga, W. Kus, C. The a.c. electrical response of LixNa₁₋xNbO₃ (LNN) solid solution in low frequency range (100 Hz–20 kHz) has been analysed as a function of temperature (300 K–750 K). A complex picture of the dependence of the studied properties on the chemical composition has been obtained. The data indicate the presence of relaxation and transport processes as well as their thermally activated character. Досліджено електричний відгук в змінному полі твердих розчинів LixNa₁₋xNbO₃ (LNN) як функцію температури (300 K–750 K) в низькочастотній області (100 Hz–20 kHz). Отримано комплексну картину залежності досліджених величин від хімічного складу. Отримані дані свідчать про наявність релаксаційних і транспортних процесів та про тепловий характер їх активації. 1999 Article Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4 / W. Bak, B. Garbarz, W. Smiga, C. Kus // Condensed Matter Physics. — 1999. — Т. 2, № 4(20). — С. 727-730. — Бібліогр.: 8 назв. — англ. 1607-324X DOI:10.5488/CMP.2.4.727 PACS: 77.84.Dy, 77.22.-d http://dspace.nbuv.gov.ua/handle/123456789/121017 en Condensed Matter Physics Інститут фізики конденсованих систем НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| description |
The a.c. electrical response of LixNa₁₋xNbO₃ (LNN) solid solution in low frequency range (100 Hz–20 kHz) has been analysed as a function of temperature (300 K–750 K). A complex picture of the dependence of the studied properties on the chemical composition has been obtained. The data indicate the presence of relaxation and transport processes as well as their thermally activated character. |
| format |
Article |
| author |
Bak, W. Garbarz, B. Smiga, W. Kus, C. |
| spellingShingle |
Bak, W. Garbarz, B. Smiga, W. Kus, C. Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4 Condensed Matter Physics |
| author_facet |
Bak, W. Garbarz, B. Smiga, W. Kus, C. |
| author_sort |
Bak, W. |
| title |
Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4 |
| title_short |
Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4 |
| title_full |
Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4 |
| title_fullStr |
Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4 |
| title_full_unstemmed |
Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4 |
| title_sort |
investigation of dielectric properties of lixna₁₋xnbo₃ ceramics for x = 1 and x=4 |
| publisher |
Інститут фізики конденсованих систем НАН України |
| publishDate |
1999 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/121017 |
| citation_txt |
Investigation of dielectric properties of LixNa₁₋xNbO₃ ceramics for x = 1 and x=4 / W. Bak, B. Garbarz, W. Smiga, C. Kus // Condensed Matter Physics. — 1999. — Т. 2, № 4(20). — С. 727-730. — Бібліогр.: 8 назв. — англ. |
| series |
Condensed Matter Physics |
| work_keys_str_mv |
AT bakw investigationofdielectricpropertiesoflixna1xnbo3ceramicsforx1andx4 AT garbarzb investigationofdielectricpropertiesoflixna1xnbo3ceramicsforx1andx4 AT smigaw investigationofdielectricpropertiesoflixna1xnbo3ceramicsforx1andx4 AT kusc investigationofdielectricpropertiesoflixna1xnbo3ceramicsforx1andx4 |
| first_indexed |
2025-07-08T19:01:47Z |
| last_indexed |
2025-07-08T19:01:47Z |
| _version_ |
1837106523851980800 |
| fulltext |
Condensed Matter Physics, 1999, Vol. 2, No. 4(20), pp. 727–730
Investigation of dielectric properties of
LixNa1−xNbO3 ceramics for x = 1 and
x = 4
W.Ba̧k, B.Garbarz, W.Śmiga, C.Kuś
Institute of Physics and Computer Science, Pedagogical University,
2 Podchora̧żych Str., 30-084 Kraków, Poland
Received September 1, 1998
The a.c. electrical response of LixNa1−xNbO3 (LNN) solid solution in low
frequency range (100 Hz–20 kHz) has been analysed as a function of tem-
perature (300 K–750 K). A complex picture of the dependence of the stud-
ied properties on the chemical composition has been obtained. The data
indicate the presence of relaxation and transport processes as well as their
thermally activated character.
Key words: LixNa1−xNbO3, ceramics, dielectric properties
PACS: 77.84.Dy, 77.22.-d
1. Introduction
Dependence of dielectric properties of Li
x
Na1−x
NbO3 (LNN) solid solution on its
chemical composition is well known. In particular, phase transformation, conduc-
tivity and dielectric permittivity of LNN have been studied [1–3]. However, some
discrepancies in the results are observed, and more systematic studies should be
undertaken to establish relations of the properties to the composition of the solid
solution.
The system NaNbO3–LiNbO3 is of interest, especially as Li content in LNN in-
creases. These materials would be good candidates for the fabrication of piezoelectric
and piroelectric components for high temperature purposes.
The investigated polycrystalline sample was obtained using the conventional ce-
ramic technology. The application of a.c. measurements method enables us to observe
the polarization processes and to gain the information about the charge transport
mechanism.
c© W.Ba̧k, B.Garbarz, W.Śmiga, C.Kuś 727
W.Ba̧k et al.
2. Experimental
The ceramic samples of LNN used in our measurements had the shape of disks
of 8–9 mm diameter and 2–3 mm thickness. Samples with sputter deposited Pt-
electrodes were used in our measurements. All the experiments have been performed
under normal atmospheric conditions. The temperature of the samples, in the range
between 300 K and 800 K, was measured by means of a chromel-alumel thermocouple
with 0.5 K accuracy. The dielectric measurements were performed by means of RLC
meter (model BM 595) at different fixed frequencies between 100 Hz and 20 kHz. In
all measurements the RLC meter was set to a parallel mode.
3. Results and discussion
The real part of the dielectric permittivity ε as a function of the temperature for
two measurement frequencies (1kHz and 10kHz) is shown in figure 1a for Li-content
x=0.01 and in figure 1b for Li-content x=0.04. As the content of Li increases ε
generally increases.
The thermal hysteresis of permittivity for two Li-contents when measurements
are made at the increasing and the decreasing temperature is due to the observed
thermal hysteresis of the dielectric anomaly caused by the antiferroelectric-parael-
ectric (A-P) phase transition of NaNbO3 [4]. There is a small shift (cooling process)
of the temperature of the ε-maximum to lower temperatures with the increasing
Li-content.
The behaviour of tan δ as a function of the temperature changes with the fre-
quency, as it is shown in figure 2a for Li-content x=0.01 and in figure 2b for Li-
content x=0.04. For low frequency (<1kHz) there is a fast increase of tan δ above
600 K. In the whole range of the investigated temperatures the value of tan δ de-
creases with the increase of frequency.
Figures 3a,b show the conductivity σ versus temperature for different measure-
ment frequencies and different Li-contents ((3a) x=0.01 and (3b) x=0.04). For Li-
content of x=0.01 there is a minimum at T=400 K, which tends to disappear as the
0
200
400
600
800
1000
1200
1400
1600
1800
2000
350 400 450 500 550 600 650 700 750
T[K]
e
1 kHz cooling 10 kHz cooling 1 kHz heating 10 kHz heating
a)
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
300 350 400 450 500 550 600 650 700 750
T [K]
e
1kHz cooling 10kHz cooling 1kHz heating 10kHz heating
b)
Figure 1. Real value of the permittivity ε as a function of the temperature at
two measurement frequencies for: (a) LNN, x=0.01; (b) LNN, x=0.04.
728
Dielectric properties of LixNa1−xNbO3 ceramics
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
350 400 450 500 550 600 650 700 750
T [K]
tg d
1 kHz 4 kHz 10 kHz
a)
0,0
0,1
0,2
0,3
0,4
300 350 400 450 500 550 600 650 700 750
T [K]
tg d
1 kHz 4 kHz 10 kHz
b)
Figure 2. Temperature dependencies of tan δ at several measurement frequencies
for: (a) LNN, x=0.01; (b) LNN, x=0.04.
frequency and Li-content increases. The low frequency (<1kHz) and low tempera-
ture (<400 K) change in the temperature coefficient of the conductivity with the
appearance of a minimum (figure 3a) was also found in lithium [5] and sodium [6]
niobates and sodium tantalate [7] at the similar temperature and lower frequencies
(1 mHz to 1 Hz). The minimum in conductivity could be related to the possible
existence of conduction mechanism of small polarons (i.e., localized charge carriers
permitted by a certain degree of structural disorder or polarizability of the surround-
ings of the charge carriers [8]) at low temperature. At low temperatures the short
range tunnelling gives place to conductivity values corresponding to long range hop-
ping, with higher activation energy that would correspond to higher temperatures
due to a low mobility of these localized charge carriers. The minimum in the thermal
behaviour of ε is, therefore, explained as the result of the change in the conductivity
mechanism, from tunnelling to hopping, from short range to long range mechanisms,
at this temperature [6].
References
1. Kuś C., Ptak W.S., Śmiga W., Ba̧k W. Temperature dependence of dielectric properties
of nonstoichiometric NaNbO3. // Acta Universitatis Wratislaviensis, 1988, No. 1084,
p. 169-175.
2. Jankowska I., Krzywanek K., Kuś C. The investigation of metastable states in
Na1−xLixNbO3 polycrystals near the diffused phase transition. // Ferroelectrics, 1992,
vol. 127, No 4, p. 83-88.
-25
-24
-23
-22
-21
-20
-19
-18
-17
1,3 1,5 1,7 1,9 2,1 2,3 2,5 2,7 2,9 3,1
1000/T [1/K]
a)
-24
-23
-22
-21
-20
-19
-18
-17
1,3 1,5 1,7 1,9 2,1 2,3 2,5 2,7 2,9
1000/T [1/K]
b)
Figure 3. Conductivity σ as a function of the temperature at two measurement
frequencies for: (a) LNN, x=0.01; (b) LNN, x=0.04.
729
W.Ba̧k et al.
3. Pardo L. et al. Temperature behaviour of structural, dielectric and piezoelectric prop-
erties of sol-gel processed ceramics of the system LiNbO3-NaNbO3. // J. Phys. Chem.
Solids, 1997, vol. 58, No 9, p. 1335-1339.
4. Kuś C., Ba̧k W., Ptak W.S., Śmiga W. Antiferroelectric- paraelectric phase transfor-
mation in nonstoichiometric NaNbO3. // Ferroelectrics, 1988, vol. 81, p. 277-280.
5. Ba̧k W., Kuś C., Ptak W.S., Śmiga W. Very low frequency study on transport and
relaxation phenomena in LiNbO3 single crystal. // Ferroelectrics, 1992, vol. 126, p. 179-
184.
6. Ba̧k W., Kuś C., Ptak W.S. The transport properties of polycrystalline NaNbO3 deter-
mined from immitance spectra at very low frequencies. // Ferroelectrics, 1991, vol. 115,
p. 105-111.
7. Aleksandrowicz A., Wójcik K. Electrical properties of single crystals and ceramic sam-
ples of NaTaO3. // Ferroelectrics, 1989, vol. 99, p. 105-113.
8. Jonscher A.K. Dielectric Relaxation. London, Chelsea Dielectric Press, 1993.
Дослідження діелектричних властивостей
LixNa1−xNbO3 керамік у випадках x = 1 і x = 4
В.Бонк, Б.Гарбаж, В.Сьміга, Ч.Кусь
Інститут фізики та обчислювальної техніки,
Педагогічний університет,
Польща, 30-084 Краків, вул. Подхоронжих, 1
Отримано 1 вересня 1998 р.
Досліджено електричний відгук в змінному полі твердих розчинів
LixNa1−xNbO3 (LNN) як функцію температури (300 K–750 K) в низь-
кочастотній області (100 Hz–20 kHz). Отримано комплексну картину
залежності досліджених величин від хімічного складу. Отримані дані
свідчать про наявність релаксаційних і транспортних процесів та про
тепловий характер їх активації.
Ключові слова: LixNa1−xNbO3, кераміки, діелектричні влатстивості
PACS: 77.84.Dy, 77.22.-d
730
|