TY  - JOUR
AU  - Jovalekić, Čedomir
AU  - Zdujić, Miodrag
PY  - 2010
UR  - https://dais.sanu.ac.rs/123456789/3431
AB  - The effect of thermal treatment atmosphere (argon, air or oxygen) on the electret behavior of bismuth titanate (Bi4Ti3O12) ceramics was investigated. Polycrystalline ferroelectric ceramics were prepared by reactive liquid phase sintering. Sintered samples were polarized applying an electric field, Ep = 1 MV m-1 at 100 °C for 60 min. Effective surface density, σeff of free charges was determined by compensation voltage measurements. Thermally treated samples in oxygen atmosphere exhibit a significant decrease of σeff while those treated in argon exhibit an increase of σeff accompanied by the improvement in stability of electret charge. In all cases homocharge with a time independent sign was obtained. © 2009 Elsevier Ltd and Techna Group S.r.l.
PB  - Elsevier
T2  - Ceramics International
T1  - Electret state in Bi4Ti3O12 ceramics
SP  - 789
EP  - 792
VL  - 36
IS  - 2
DO  - 10.1016/j.ceramint.2009.09.019
UR  - https://hdl.handle.net/21.15107/rcub_dais_3431
ER  - 

@article{
author = "Jovalekić, Čedomir and Zdujić, Miodrag",
year = "2010",
abstract = "The effect of thermal treatment atmosphere (argon, air or oxygen) on the electret behavior of bismuth titanate (Bi4Ti3O12) ceramics was investigated. Polycrystalline ferroelectric ceramics were prepared by reactive liquid phase sintering. Sintered samples were polarized applying an electric field, Ep = 1 MV m-1 at 100 °C for 60 min. Effective surface density, σeff of free charges was determined by compensation voltage measurements. Thermally treated samples in oxygen atmosphere exhibit a significant decrease of σeff while those treated in argon exhibit an increase of σeff accompanied by the improvement in stability of electret charge. In all cases homocharge with a time independent sign was obtained. © 2009 Elsevier Ltd and Techna Group S.r.l.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Electret state in Bi4Ti3O12 ceramics",
pages = "789-792",
volume = "36",
number = "2",
doi = "10.1016/j.ceramint.2009.09.019",
url = "https://hdl.handle.net/21.15107/rcub_dais_3431"
}

Jovalekić, Č.,& Zdujić, M.. (2010). Electret state in Bi4Ti3O12 ceramics. in Ceramics International
Elsevier., 36(2), 789-792.
https://doi.org/10.1016/j.ceramint.2009.09.019
https://hdl.handle.net/21.15107/rcub_dais_3431

Jovalekić Č, Zdujić M. Electret state in Bi4Ti3O12 ceramics. in Ceramics International. 2010;36(2):789-792.
doi:10.1016/j.ceramint.2009.09.019
https://hdl.handle.net/21.15107/rcub_dais_3431 .

Jovalekić, Čedomir, Zdujić, Miodrag, "Electret state in Bi4Ti3O12 ceramics" in Ceramics International, 36, no. 2 (2010):789-792,
https://doi.org/10.1016/j.ceramint.2009.09.019 .,
https://hdl.handle.net/21.15107/rcub_dais_3431 .

TY  - JOUR
AU  - Jovalekić, Čedomir
AU  - Zdujić, Miodrag
AU  - Atanasoska, Ljiljana
PY  - 2009
UR  - https://dais.sanu.ac.rs/123456789/3469
AB  - The Auger and XPS technique has been used for investigation in the surface of bismuth titanate (Bi4Ti3O12) (BIT) ceramics obtained by reactive sintering from Bi2O3 and TiO2 oxides. All peaks characteristic for bismuth, titanium and oxygen are clearly visible in the spectrum. Oxygen vacancies are preferentially sited in the vicinity of bismuth ions observed by our X-ray photoemission data. The variation in the valence state of titanium ions is also possible. The XPS and AES measurements confirm that the surface elemental composition of bismuth titanate ceramics does not deviate from nominal bulk composition. © 2008 Elsevier B.V. All rights reserved.
PB  - Elsevier
T2  - Journal of Alloys and Compounds
T1  - Surface analysis of bismuth titanate by Auger and X-ray photoelectron spectroscopy
SP  - 441
EP  - 444
VL  - 469
IS  - 1-2
DO  - 10.1016/j.jallcom.2008.01.131
UR  - https://hdl.handle.net/21.15107/rcub_dais_3469
ER  - 

@article{
author = "Jovalekić, Čedomir and Zdujić, Miodrag and Atanasoska, Ljiljana",
year = "2009",
abstract = "The Auger and XPS technique has been used for investigation in the surface of bismuth titanate (Bi4Ti3O12) (BIT) ceramics obtained by reactive sintering from Bi2O3 and TiO2 oxides. All peaks characteristic for bismuth, titanium and oxygen are clearly visible in the spectrum. Oxygen vacancies are preferentially sited in the vicinity of bismuth ions observed by our X-ray photoemission data. The variation in the valence state of titanium ions is also possible. The XPS and AES measurements confirm that the surface elemental composition of bismuth titanate ceramics does not deviate from nominal bulk composition. © 2008 Elsevier B.V. All rights reserved.",
publisher = "Elsevier",
journal = "Journal of Alloys and Compounds",
title = "Surface analysis of bismuth titanate by Auger and X-ray photoelectron spectroscopy",
pages = "441-444",
volume = "469",
number = "1-2",
doi = "10.1016/j.jallcom.2008.01.131",
url = "https://hdl.handle.net/21.15107/rcub_dais_3469"
}

Jovalekić, Č., Zdujić, M.,& Atanasoska, L.. (2009). Surface analysis of bismuth titanate by Auger and X-ray photoelectron spectroscopy. in Journal of Alloys and Compounds
Elsevier., 469(1-2), 441-444.
https://doi.org/10.1016/j.jallcom.2008.01.131
https://hdl.handle.net/21.15107/rcub_dais_3469

Jovalekić Č, Zdujić M, Atanasoska L. Surface analysis of bismuth titanate by Auger and X-ray photoelectron spectroscopy. in Journal of Alloys and Compounds. 2009;469(1-2):441-444.
doi:10.1016/j.jallcom.2008.01.131
https://hdl.handle.net/21.15107/rcub_dais_3469 .

Jovalekić, Čedomir, Zdujić, Miodrag, Atanasoska, Ljiljana, "Surface analysis of bismuth titanate by Auger and X-ray photoelectron spectroscopy" in Journal of Alloys and Compounds, 469, no. 1-2 (2009):441-444,
https://doi.org/10.1016/j.jallcom.2008.01.131 .,
https://hdl.handle.net/21.15107/rcub_dais_3469 .

TY  - JOUR
AU  - Zdujić, Miodrag
AU  - Jovalekić, Čedomir
AU  - Poleti, Dejan
AU  - Veljković, Ivana
AU  - Karanović, Ljiljana
PY  - 2009
UR  - https://dais.sanu.ac.rs/123456789/3454
AB  - Concurrent milling of Bi4Ti3O12 was carried out in a planetary ball mill with hardened-steel 13 or 6 mm diameter balls with a goal to investigate how the system responds to the constrains imposed by milling. Milling intensity for various milling parameters was derived from the electrical power measurement. The reverse amorphous ↔ crystalline phase transition induced by milling is governed by impact energy and frequency. Below a certain threshold value of impact energy crystallization does not occur, whereas a higher impact frequency accelerates amorphization. Mechanochemical reactions are predominantly discrete processes, which occur at the moment of impact. © 2009 Elsevier B.V. All rights reserved.
PB  - Elsevier
T2  - Materials Letters
T1  - Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound
SP  - 2542
EP  - 2544
VL  - 63
IS  - 29
DO  - 10.1016/j.matlet.2009.08.055
UR  - https://hdl.handle.net/21.15107/rcub_dais_3454
ER  - 

@article{
author = "Zdujić, Miodrag and Jovalekić, Čedomir and Poleti, Dejan and Veljković, Ivana and Karanović, Ljiljana",
year = "2009",
abstract = "Concurrent milling of Bi4Ti3O12 was carried out in a planetary ball mill with hardened-steel 13 or 6 mm diameter balls with a goal to investigate how the system responds to the constrains imposed by milling. Milling intensity for various milling parameters was derived from the electrical power measurement. The reverse amorphous ↔ crystalline phase transition induced by milling is governed by impact energy and frequency. Below a certain threshold value of impact energy crystallization does not occur, whereas a higher impact frequency accelerates amorphization. Mechanochemical reactions are predominantly discrete processes, which occur at the moment of impact. © 2009 Elsevier B.V. All rights reserved.",
publisher = "Elsevier",
journal = "Materials Letters",
title = "Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound",
pages = "2542-2544",
volume = "63",
number = "29",
doi = "10.1016/j.matlet.2009.08.055",
url = "https://hdl.handle.net/21.15107/rcub_dais_3454"
}

Zdujić, M., Jovalekić, Č., Poleti, D., Veljković, I.,& Karanović, L.. (2009). Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound. in Materials Letters
Elsevier., 63(29), 2542-2544.
https://doi.org/10.1016/j.matlet.2009.08.055
https://hdl.handle.net/21.15107/rcub_dais_3454

Zdujić M, Jovalekić Č, Poleti D, Veljković I, Karanović L. Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound. in Materials Letters. 2009;63(29):2542-2544.
doi:10.1016/j.matlet.2009.08.055
https://hdl.handle.net/21.15107/rcub_dais_3454 .

Zdujić, Miodrag, Jovalekić, Čedomir, Poleti, Dejan, Veljković, Ivana, Karanović, Ljiljana, "Mechanochemically induced amorphous/crystalline phase transition in the Bi4Ti3O12 compound" in Materials Letters, 63, no. 29 (2009):2542-2544,
https://doi.org/10.1016/j.matlet.2009.08.055 .,
https://hdl.handle.net/21.15107/rcub_dais_3454 .

TY  - JOUR
AU  - Zdujić, Miodrag
AU  - Poleti, Dejan
AU  - Jovalekić, Čedomir
AU  - Karanović, Ljiljana
PY  - 2009
UR  - https://dais.sanu.ac.rs/123456789/174
AB  - A powder mixture of α-Bi2O3 and HfO2, in the molar ratio 2:3, was mechanochemically treated in a planetary ball mill under air, using zirconium oxide vials and balls as the milling medium. After 50 h of milling, the mechanochemical reaction led to the formation of a nanocrystalline δ-Bi2O3 phase (fluorite-type solid solution Bi0.78Hf0.59Zr0.63O3.61), with a crystallite size of 20 nm. The mechanochemical reaction started at a very beginning of milling accompanied by an accumulation of ZrO2 arising from the milling tools. The samples prepared after various milling times were characterized by X-ray powder diffraction and DSC analysis. The electrical properties of the as-milled and pressed Bi0.78Hf0.59Zr0.63O3.61 powder were studied using impedance spectroscopy in the temperature range from 100 to 700°C under air. The electrical conductivity was determined to be 9.43×10-6 and 0.080 S cm-1 for the temperatures of 300 and 700°C, respectively.
AB  - Smeša prahova α-Bi2O3 i HfO2 u molarnom odnosu 2:3 mehanohemijski je tretirana u planetarnom mlinu u atmosferi vazduha, koristeći cirkonijumske posude i kuglice kao medijum za mlevenje. Posle 50 h mlevenja, mehanohemijska reakcija dovodi do stvaranja nanokristalne δ-Bi2O3 faze (čvrsti rastvor fluoritske strukture Bi0,78Hf0,59Zr0,63O3,61), veličine kristalita 20 nm. Mehanohemijska reakcija otpočinje u samom početku mlevenja i praćena je akumulacijum ZrO2 koji potiče od medijuma za mlevenje. Uzorci dobijeni posle različitih vremena mlevenja karakterisani su rendgenskom strukturnom i termijskom analizom. Električna svojstva mlevenih i presovanih Bi0,78Hf0,59Zr0,63O3,61 prahova ispitivana su impedansnom spektroskopijom u temperaturnom opsegu od 100 do 700°C. Dobijena električna provodnost je 9,43·10-6 i 0,080 S cm-1 za temperaturu 300 i 700°C, redom.
PB  - Belgrade : Serbian Chemical Society
T2  - Journal of the Serbian Chemical Society
T1  - Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2
SP  - 1401
EP  - 1411
VL  - 74
IS  - 12
DO  - 10.2298/JSC0912401Z
UR  - https://hdl.handle.net/21.15107/rcub_dais_174
ER  - 

@article{
author = "Zdujić, Miodrag and Poleti, Dejan and Jovalekić, Čedomir and Karanović, Ljiljana",
year = "2009",
abstract = "A powder mixture of α-Bi2O3 and HfO2, in the molar ratio 2:3, was mechanochemically treated in a planetary ball mill under air, using zirconium oxide vials and balls as the milling medium. After 50 h of milling, the mechanochemical reaction led to the formation of a nanocrystalline δ-Bi2O3 phase (fluorite-type solid solution Bi0.78Hf0.59Zr0.63O3.61), with a crystallite size of 20 nm. The mechanochemical reaction started at a very beginning of milling accompanied by an accumulation of ZrO2 arising from the milling tools. The samples prepared after various milling times were characterized by X-ray powder diffraction and DSC analysis. The electrical properties of the as-milled and pressed Bi0.78Hf0.59Zr0.63O3.61 powder were studied using impedance spectroscopy in the temperature range from 100 to 700°C under air. The electrical conductivity was determined to be 9.43×10-6 and 0.080 S cm-1 for the temperatures of 300 and 700°C, respectively., Smeša prahova α-Bi2O3 i HfO2 u molarnom odnosu 2:3 mehanohemijski je tretirana u planetarnom mlinu u atmosferi vazduha, koristeći cirkonijumske posude i kuglice kao medijum za mlevenje. Posle 50 h mlevenja, mehanohemijska reakcija dovodi do stvaranja nanokristalne δ-Bi2O3 faze (čvrsti rastvor fluoritske strukture Bi0,78Hf0,59Zr0,63O3,61), veličine kristalita 20 nm. Mehanohemijska reakcija otpočinje u samom početku mlevenja i praćena je akumulacijum ZrO2 koji potiče od medijuma za mlevenje. Uzorci dobijeni posle različitih vremena mlevenja karakterisani su rendgenskom strukturnom i termijskom analizom. Električna svojstva mlevenih i presovanih Bi0,78Hf0,59Zr0,63O3,61 prahova ispitivana su impedansnom spektroskopijom u temperaturnom opsegu od 100 do 700°C. Dobijena električna provodnost je 9,43·10-6 i 0,080 S cm-1 za temperaturu 300 i 700°C, redom.",
publisher = "Belgrade : Serbian Chemical Society",
journal = "Journal of the Serbian Chemical Society",
title = "Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2",
pages = "1401-1411",
volume = "74",
number = "12",
doi = "10.2298/JSC0912401Z",
url = "https://hdl.handle.net/21.15107/rcub_dais_174"
}

Zdujić, M., Poleti, D., Jovalekić, Č.,& Karanović, L.. (2009). Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2. in Journal of the Serbian Chemical Society
Belgrade : Serbian Chemical Society., 74(12), 1401-1411.
https://doi.org/10.2298/JSC0912401Z
https://hdl.handle.net/21.15107/rcub_dais_174

Zdujić M, Poleti D, Jovalekić Č, Karanović L. Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2. in Journal of the Serbian Chemical Society. 2009;74(12):1401-1411.
doi:10.2298/JSC0912401Z
https://hdl.handle.net/21.15107/rcub_dais_174 .

Zdujić, Miodrag, Poleti, Dejan, Jovalekić, Čedomir, Karanović, Ljiljana, "Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2" in Journal of the Serbian Chemical Society, 74, no. 12 (2009):1401-1411,
https://doi.org/10.2298/JSC0912401Z .,
https://hdl.handle.net/21.15107/rcub_dais_174 .

TY  - JOUR
AU  - Jovalekić, Čedomir
AU  - Zdujić, Miodrag
AU  - Poleti, Dejan
AU  - Karanović, Ljiljana
AU  - Mitrić, Miodrag
PY  - 2008
UR  - https://dais.sanu.ac.rs/123456789/3582
AB  - Powder mixtures of α-Bi2O3 (bismite) and monoclinic m-ZrO2 (baddeleyite) in the molar ratio 2:3 were mechanochemically and thermally treated with the goal to examine the phases, which may appear during such procedures. The prepared samples were characterized by X-ray powder diffraction, differential scanning calorimetry (DSC), electrical measurements, as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanochemical reaction leads to the gradual formation of a nanocrystalline phase, which resembles δ-Bi2O3, a high-temperature Bi2O3 polymorph. Isothermal sintering in air at a temperature of 820 °C for 24 h followed by quenching to room temperature yielded a mixture of ZrO2-stabilized β-Bi2O3 and m-ZrO2 phases, whereas in slowly cooled products, the complete separation of the initial α-Bi2O3 and m-ZrO2 constituents was observed. The dielectric permittivity of the sintered samples significantly depended on the temperature. The sintered and quenched samples exhibited a hysteresis dependence of the dielectric shift, showing that the ZrO2-doped β-Bi2O3 phase possess ferroelectric properties, which were detected for the first time. This fact, together with Rietveld refinement of the β-Bi2O3/m-ZrO2 mixture based on neutron powder diffraction data showed that ZrO2-doped β-Bi2O3 has a non-centrosymmetric structure with P over(4, -) 21 c as the true space group. The ZrO2 content in the doped β-Bi2O3 and the crystal chemical reasons for the stabilization of the β-Bi2O3 phase by the addition of m-ZrO2 are discussed. © 2008 Elsevier Inc. All rights reserved.
T2  - Journal of Solid State Chemistry
T1  - Structural and electrical properties of the 2Bi2O3·3ZrO2 system
SP  - 1321
EP  - 1329
VL  - 181
IS  - 6
DO  - 10.1016/j.jssc.2008.02.038
UR  - https://hdl.handle.net/21.15107/rcub_dais_3582
ER  - 

@article{
author = "Jovalekić, Čedomir and Zdujić, Miodrag and Poleti, Dejan and Karanović, Ljiljana and Mitrić, Miodrag",
year = "2008",
abstract = "Powder mixtures of α-Bi2O3 (bismite) and monoclinic m-ZrO2 (baddeleyite) in the molar ratio 2:3 were mechanochemically and thermally treated with the goal to examine the phases, which may appear during such procedures. The prepared samples were characterized by X-ray powder diffraction, differential scanning calorimetry (DSC), electrical measurements, as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanochemical reaction leads to the gradual formation of a nanocrystalline phase, which resembles δ-Bi2O3, a high-temperature Bi2O3 polymorph. Isothermal sintering in air at a temperature of 820 °C for 24 h followed by quenching to room temperature yielded a mixture of ZrO2-stabilized β-Bi2O3 and m-ZrO2 phases, whereas in slowly cooled products, the complete separation of the initial α-Bi2O3 and m-ZrO2 constituents was observed. The dielectric permittivity of the sintered samples significantly depended on the temperature. The sintered and quenched samples exhibited a hysteresis dependence of the dielectric shift, showing that the ZrO2-doped β-Bi2O3 phase possess ferroelectric properties, which were detected for the first time. This fact, together with Rietveld refinement of the β-Bi2O3/m-ZrO2 mixture based on neutron powder diffraction data showed that ZrO2-doped β-Bi2O3 has a non-centrosymmetric structure with P over(4, -) 21 c as the true space group. The ZrO2 content in the doped β-Bi2O3 and the crystal chemical reasons for the stabilization of the β-Bi2O3 phase by the addition of m-ZrO2 are discussed. © 2008 Elsevier Inc. All rights reserved.",
journal = "Journal of Solid State Chemistry",
title = "Structural and electrical properties of the 2Bi2O3·3ZrO2 system",
pages = "1321-1329",
volume = "181",
number = "6",
doi = "10.1016/j.jssc.2008.02.038",
url = "https://hdl.handle.net/21.15107/rcub_dais_3582"
}

Jovalekić, Č., Zdujić, M., Poleti, D., Karanović, L.,& Mitrić, M.. (2008). Structural and electrical properties of the 2Bi2O3·3ZrO2 system. in Journal of Solid State Chemistry, 181(6), 1321-1329.
https://doi.org/10.1016/j.jssc.2008.02.038
https://hdl.handle.net/21.15107/rcub_dais_3582

Jovalekić Č, Zdujić M, Poleti D, Karanović L, Mitrić M. Structural and electrical properties of the 2Bi2O3·3ZrO2 system. in Journal of Solid State Chemistry. 2008;181(6):1321-1329.
doi:10.1016/j.jssc.2008.02.038
https://hdl.handle.net/21.15107/rcub_dais_3582 .

Jovalekić, Čedomir, Zdujić, Miodrag, Poleti, Dejan, Karanović, Ljiljana, Mitrić, Miodrag, "Structural and electrical properties of the 2Bi2O3·3ZrO2 system" in Journal of Solid State Chemistry, 181, no. 6 (2008):1321-1329,
https://doi.org/10.1016/j.jssc.2008.02.038 .,
https://hdl.handle.net/21.15107/rcub_dais_3582 .