Temperature changes of Seebeck coefficient of SbSJ modified

The temperature dependency of Seebeck coefficient has been measured for a needle-shaped crystal of SbSJ:0.1%Cl. The measurements have been made in the temperature range from 190 K to 370 K. The obtained results made it possible to determine the type and the mechanisms of electric conduction. В робот...

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Published in:Condensed Matter Physics
Date:1999
Main Author: Garbarz, B.
Format: Article
Language:English
Published: Інститут фізики конденсованих систем НАН України 1999
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/120587
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Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:Temperature changes of Seebeck coefficient of SbSJ modified / B. Garbarz // Condensed Matter Physics. — 1999. — Т. 2, № 4(20). — С. 621-624. — Бібліогр.: 6 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-120587
record_format dspace
spelling Garbarz, B.
2017-06-12T11:56:20Z
2017-06-12T11:56:20Z
1999
Temperature changes of Seebeck coefficient of SbSJ modified / B. Garbarz // Condensed Matter Physics. — 1999. — Т. 2, № 4(20). — С. 621-624. — Бібліогр.: 6 назв. — англ.
1607-324X
DOI:10.5488/CMP.2.4.621
PACS: 72.20.-i, 77.84.-s, 72.80.-r
https://nasplib.isofts.kiev.ua/handle/123456789/120587
The temperature dependency of Seebeck coefficient has been measured for a needle-shaped crystal of SbSJ:0.1%Cl. The measurements have been made in the temperature range from 190 K to 370 K. The obtained results made it possible to determine the type and the mechanisms of electric conduction.
В роботі наведено результати вимірювань коефіцієнта Зеебека для кристалу SbSJ:0.1%Cl голкоподібної форми в діапазоні температур від 190 K до 370 K. Отримані результати дають можливість визначити тип і механізм електричної провідності в цьому кристалі.
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Інститут фізики конденсованих систем НАН України
Condensed Matter Physics
Temperature changes of Seebeck coefficient of SbSJ modified
Температурні зміни коефіцієнта Зеебека у модифікованому SbSJ
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Temperature changes of Seebeck coefficient of SbSJ modified
spellingShingle Temperature changes of Seebeck coefficient of SbSJ modified
Garbarz, B.
title_short Temperature changes of Seebeck coefficient of SbSJ modified
title_full Temperature changes of Seebeck coefficient of SbSJ modified
title_fullStr Temperature changes of Seebeck coefficient of SbSJ modified
title_full_unstemmed Temperature changes of Seebeck coefficient of SbSJ modified
title_sort temperature changes of seebeck coefficient of sbsj modified
author Garbarz, B.
author_facet Garbarz, B.
publishDate 1999
language English
container_title Condensed Matter Physics
publisher Інститут фізики конденсованих систем НАН України
format Article
title_alt Температурні зміни коефіцієнта Зеебека у модифікованому SbSJ
description The temperature dependency of Seebeck coefficient has been measured for a needle-shaped crystal of SbSJ:0.1%Cl. The measurements have been made in the temperature range from 190 K to 370 K. The obtained results made it possible to determine the type and the mechanisms of electric conduction. В роботі наведено результати вимірювань коефіцієнта Зеебека для кристалу SbSJ:0.1%Cl голкоподібної форми в діапазоні температур від 190 K до 370 K. Отримані результати дають можливість визначити тип і механізм електричної провідності в цьому кристалі.
issn 1607-324X
url https://nasplib.isofts.kiev.ua/handle/123456789/120587
citation_txt Temperature changes of Seebeck coefficient of SbSJ modified / B. Garbarz // Condensed Matter Physics. — 1999. — Т. 2, № 4(20). — С. 621-624. — Бібліогр.: 6 назв. — англ.
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fulltext Condensed Matter Physics, 1999, Vol. 2, No. 4(20), pp. 621–624 Temperature changes of Seebeck coefficient of SbSJ modified B.Garbarz Institute of Physics and Computer Science, Pedagogical University, 2 Podchora̧żych Str., 30-084 Kraków, Poland Received September 1, 1998, in final form October 30, 1999 The temperature dependency of Seebeck coefficient has been measured for a needle-shaped crystal of SbSJ:0.1%Cl. The measurements have been made in the temperature range from 190 K to 370 K. The obtained results made it possible to determine the type and the mechanisms of electric con- duction. Key words: SbSJ, Seebeck coefficient PACS: 72.20.-i, 77.84.-s, 72.80.-r 1. Introduction A remarkably interesting coexistence of ferroelectric and semiconducting prop- erties and the possibility of their practical application causes a great interest in investigating the semiconducting ferroelectric materials. They form a separate class of non-linear ferroelectrics, in which several new phenomena and properties can be observed, and in which most processes reveal specific singularities in the phase tran- sition points. However, a great variety of structural defects, an indeterminate band structure, a complicated dependence of current components, and so on, make them inconvenient for investigations. Among the materials revealing the ferroelectric phase transitions and, at the same time, the semiconducting properties, a special group is formed by the complexes of A5B6C7-type. To this group belongs the antimony sulphide iodide SbSJ. Pure SbSJ has been investigated by various workers over the years [1–5]. Because of too little information about the electric properties of SbSJ:0.01% Cl, the author of this paper has undertaken the investigations of temperature changes of Seebeck coefficient of this material. The measurements were performed in the temperature range from 190 K to 370 K (this covers the ranges, where ferroelectric and paraelectric phases occur). It was interesting to know whether the changes of Seebeck coefficient and of the investigated quantities would take place. c© B.Garbarz 621 B.Garbarz 2. Experiment In order to determine the mechanisms of transport, the attempt to investigate the Seebeck effect was undertaken. The applied method of measuring the Seebeck coefficient has been described in [6]. The experiment was made using an automatic measuring device, which gives linear changes of the temperature gradient in the sample, while the average temperature of the sample remains constant at measuring the thermoelectric power. The device allows for a simultaneous measurement of the Seebeck coefficient. The temperature difference between two opposite surfaces of the sample was changed from +6 K to –6 K with the rate of 1 K/min. During the measurements the average temperature stabilized within the uncertainty of ±0.5 K. The sample used in our measurements had the shape of a disk (the diameter d of which was equal to 0.00377 m and the surface S was equal to 0.00006 m2) with the deposited platinic electrodes. The platinum electrodes were placed on the sample by means of the vacuum evaporation techniques. 3. Experimental results and discussion The type of electrical conduction was determined based on of the sign of the thermoelectric power of the sample-electrode colder junction. In SbSJ-modified, the n type was observed. The investigation of Seebeck effect consists in measuring the thermoelectric power Eα at a fixed gradient of temperature ∆T in the sample. When changing the magnitude and direction of the temperature gradient, the dependence Eα(∆t) is determined at a constant average temperature of the system (figures 1,2). Figure 1 shows the dependence of the thermoelectric power on the temperature gradient. We can see that this dependence is linear and for different average tem- peratures the parameters E0 are different. The dependence Eα = Eα(∆T ) can be expressed by the equation: Eα = E0 + a∆T , where ∆T = T2 − T1, E0 – the value the thermoelectric power for ∆T=0, T1, T2 – the temperatures of the surface of the sample with electrodes. The examples of temperature changes of E0 observed in SbSJ:0.1%Cl-crystals are shown in figure 2. The character of temperature dependence of this quantity is the evidence of its connection with the value and with the sign of the effective polarization (of spontaneous polarization and space charge). The value E0 depends on the history of the sample and particularly on the previous acting of an electric field. It does not effect the value of the coefficient α. Using the above equation the Seebeck coefficients for different average tempera- tures are shown in figure 3. The course of the temperature dependence of Seebeck coefficient (figure 3) and the fact, that it changes its sign with the change of tem- perature indicate the significant contribution of both kinds of charge carriers (i.e. electrons and holes) to the charge transport. The observed dependence can result from the change of carriers number with the temperature change and with the loca- tion of the acceptor and donor levels relative to the valence and conduction bands. 622 Temperature changes of Seebeck coefficient . . . 6,8 7,0 7,2 7,4 7,6 7,8 8,0 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 D T [K] E [m V ] 324 K 330 K 361K 351 K 343 K Figure 1. The dependence of the thermoelectric power versus temperature gra- dient. 7 7,1 7,2 7,3 7,4 7,5 7,6 7,7 7,8 7,9 8 320 330 340 350 360 370 T [K] E 0 [m V ] Figure 2. Temperature dependence of the thermoelectric power. -0,2 -0,1 0 0,1 0,2 0,3 0,4 2,75 2,8 2,85 2,9 2,95 3 3,05 3,1 3,15 1000/T [K -1 ] a [m v /K ] Figure 3. Temperature dependence of Seebeck coefficient. 623 B.Garbarz References 1. Steigmeier E.F., Auderset H., Haberke G. The central peak in SbSJ. // Phys. Stat. Sol. (b), 1975, vol. 70, p. 705–716. 2. Grigas J. Microwave Dielectric Spectroscopy of Ferroelectrics and Related Materials. Gordon and Breach Publishers, 1996. 3. Fridkin V.M. Photo-ferroelectrics. Berlin, Heidelberg, New–York, Springer Verlag, 1979. 4. Gierzanicz E.I., Fridkin V.M. Segnetoelektriki Tipa AV BV I CV II . Moskwa, Nauka, 1962 (in Russian). 5. Kudzin A.Yu., Suhynski A.N. Wlijanie oswieszczenia na formirowanie pietli dielek- triczeskogo gisterezisa monokristalow SbSJ. // Solid State Physics, 1969, vol. 11, No. 6, p. 1389–1391. 6. Kuś C, Śmiga W., Suchanicz J. Temperature changes of the Seebeck coefficient for non- stoichiometric NaNbO3. // Acta Universitatis Wratislaviensis, 1988, vol. 1084, p. 185– 191. Температурні зміни коефіцієнта Зеебека у модифікованому SbSJ Б.Гарбаж Інститут фізики та обчислювальної техніки, Педагогічний університет, Польща, 30-084 Краків, вул. Подхоронжих, 1 Отримано 1 вересня 1998 р., в остаточному вигляді – 30 жовтня 1999 р. В роботі наведено результати вимірювань коефіцієнта Зеебека для кристалу SbSJ:0.1%Cl голкоподібної форми в діапазоні температур від 190 K до 370 K. Отримані результати дають можливість визначити тип і механізм електричної провідності в цьому кристалі. Ключові слова: SbSJ, коефіцієнт Зеебека PACS: 72.20.-i, 77.84.-s, 72.80.-r 624