TY  - JOUR
AU  - Perać, Sanja
AU  - Savić, Slavica M.
AU  - Branković, Zorica
AU  - Jaglicic, Zvonko
AU  - Vrtnik, Stanislav
AU  - Branković, Goran
PY  - 2017
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1029
AB  - Polycrystalline samples of NaCo2-xCuxO4 (x=0, 0.01, 0.03 and 0.05) were synthesized in two different ways: 1) by a mechanochemically assisted solid-state reaction method (MASSR) and 2) by a citric acid complex method (CAC). In this work we examined the influence of these synthesis routes and small Cu concentrations on magnetic properties and the heat capacity of sintered samples. The magnetic susceptibility (chi) of all samples followed the Curie-Weiss law in the temperature range between 50 K and 300 K, while a negative Weiss constant (theta) implied an antiferromagnetic interaction. According to the magnetic susceptibility data, a peak around 30 K indicating the presence of Co3O4 as a secondary phase appeared for all MASSR samples and CAC samples with Cu content above 1%. The effective magnetic moment (mu(eff)) of CAC samples was lower than the theoretical, spin only value obtained for the Co4+ ion in the low spin state indicating the presence of low spin Co3+(S = 0). These values were also lower compared to the values obtained for MASSR samples. The highest mu(eff) of 1.75 mu B/atom Co was obtained for the undoped MASSR sample. The heat capacity of CAC samples at 2 K decreased with Cu concentration due to lowering of the electronic specific heat coefficient (gamma). The highest gamma of 63.9 mJ/molK(2) was obtained for the undoped CAC sample. This reduction in gamma values was the result of the decrease of the density of state and/or mass enhancement factor.
PB  - Elsevier Sci Ltd, Oxford
T2  - Ceramics International
T1  - Antiferromagnetism and heat capacity of NaCo2-xCuxO4 ceramics
EP  - 2026
IS  - 2
SP  - 2022
VL  - 43
DO  - 10.1016/j.ceramint.2016.10.170
ER  - 

@article{
author = "Perać, Sanja and Savić, Slavica M. and Branković, Zorica and Jaglicic, Zvonko and Vrtnik, Stanislav and Branković, Goran",
year = "2017",
abstract = "Polycrystalline samples of NaCo2-xCuxO4 (x=0, 0.01, 0.03 and 0.05) were synthesized in two different ways: 1) by a mechanochemically assisted solid-state reaction method (MASSR) and 2) by a citric acid complex method (CAC). In this work we examined the influence of these synthesis routes and small Cu concentrations on magnetic properties and the heat capacity of sintered samples. The magnetic susceptibility (chi) of all samples followed the Curie-Weiss law in the temperature range between 50 K and 300 K, while a negative Weiss constant (theta) implied an antiferromagnetic interaction. According to the magnetic susceptibility data, a peak around 30 K indicating the presence of Co3O4 as a secondary phase appeared for all MASSR samples and CAC samples with Cu content above 1%. The effective magnetic moment (mu(eff)) of CAC samples was lower than the theoretical, spin only value obtained for the Co4+ ion in the low spin state indicating the presence of low spin Co3+(S = 0). These values were also lower compared to the values obtained for MASSR samples. The highest mu(eff) of 1.75 mu B/atom Co was obtained for the undoped MASSR sample. The heat capacity of CAC samples at 2 K decreased with Cu concentration due to lowering of the electronic specific heat coefficient (gamma). The highest gamma of 63.9 mJ/molK(2) was obtained for the undoped CAC sample. This reduction in gamma values was the result of the decrease of the density of state and/or mass enhancement factor.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Ceramics International",
title = "Antiferromagnetism and heat capacity of NaCo2-xCuxO4 ceramics",
pages = "2026-2022",
number = "2",
volume = "43",
doi = "10.1016/j.ceramint.2016.10.170"
}

Perać, S., Savić, S. M., Branković, Z., Jaglicic, Z., Vrtnik, S.,& Branković, G.. (2017). Antiferromagnetism and heat capacity of NaCo2-xCuxO4 ceramics. in Ceramics International
Elsevier Sci Ltd, Oxford., 43(2), 2022-2026.
https://doi.org/10.1016/j.ceramint.2016.10.170

Perać S, Savić SM, Branković Z, Jaglicic Z, Vrtnik S, Branković G. Antiferromagnetism and heat capacity of NaCo2-xCuxO4 ceramics. in Ceramics International. 2017;43(2):2022-2026.
doi:10.1016/j.ceramint.2016.10.170 .

Perać, Sanja, Savić, Slavica M., Branković, Zorica, Jaglicic, Zvonko, Vrtnik, Stanislav, Branković, Goran, "Antiferromagnetism and heat capacity of NaCo2-xCuxO4 ceramics" in Ceramics International, 43, no. 2 (2017):2022-2026,
https://doi.org/10.1016/j.ceramint.2016.10.170 . .

TY  - JOUR
AU  - Perać, Sanja
AU  - Savić, Slavica M.
AU  - Branković, Zorica
AU  - Vrtnik, Stanislav
AU  - Dapčević, Aleksandra
AU  - Branković, Goran
PY  - 2015
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/861
AB  - In the last decade, the sodium cobaltite ceramic became a promising candidate for potential thermoelectric applications, because of its large thermopower and low resistivity. In this work, polycrystalline samples of NaCo(2-x)CuxO(4) (x = 0, 0.01, 0.03, 0.05) were prepared using mechanochemically assisted solid-state reaction method (MASSR) and the citric acid complex method (CAC). Bulk samples were prepared by pressing into disc-shaped pellets and subsequently subjected to a thermal treatment at 880 degrees C in inert argon atmosphere. Changes in structural and microstructural characteristics of the samples, caused by the substitution of Cu for Co, were characterized using X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM), respectively. The results of inductively coupled plasma (ICP) analysis showed that the compositions of the final products correspond to gamma-NaCo2O4 and confirmed that desired compound was obtained in both syntheses procedures. The advantages and disadvantages of these two syntheses procedures have been observed and discussed: the CAC method enabled obtaining samples with higher density and fine microstructure compared to the MASSR method, thus better thermoelectric properties. The Cu2+ substitution led to the increase in Seebeck coefficient in both synthesis routes. The highest figure of merit of 0.022 at 300 K was observed for the sample doped with 1 mol% Cu, obtained by the CAC method, and it was almost twice higher than in the undoped sample confirming the significant influence of Cu-doping with even small concentrations.
PB  - Elsevier Science Sa, Lausanne
T2  - Journal of Alloys and Compounds
T1  - Mechanochemically assisted solid-state and citric acid complex syntheses of Cu-doped sodium cobaltite ceramics
EP  - 487
SP  - 480
VL  - 640
DO  - 10.1016/j.jallcom.2015.04.003
ER  - 

@article{
author = "Perać, Sanja and Savić, Slavica M. and Branković, Zorica and Vrtnik, Stanislav and Dapčević, Aleksandra and Branković, Goran",
year = "2015",
abstract = "In the last decade, the sodium cobaltite ceramic became a promising candidate for potential thermoelectric applications, because of its large thermopower and low resistivity. In this work, polycrystalline samples of NaCo(2-x)CuxO(4) (x = 0, 0.01, 0.03, 0.05) were prepared using mechanochemically assisted solid-state reaction method (MASSR) and the citric acid complex method (CAC). Bulk samples were prepared by pressing into disc-shaped pellets and subsequently subjected to a thermal treatment at 880 degrees C in inert argon atmosphere. Changes in structural and microstructural characteristics of the samples, caused by the substitution of Cu for Co, were characterized using X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM), respectively. The results of inductively coupled plasma (ICP) analysis showed that the compositions of the final products correspond to gamma-NaCo2O4 and confirmed that desired compound was obtained in both syntheses procedures. The advantages and disadvantages of these two syntheses procedures have been observed and discussed: the CAC method enabled obtaining samples with higher density and fine microstructure compared to the MASSR method, thus better thermoelectric properties. The Cu2+ substitution led to the increase in Seebeck coefficient in both synthesis routes. The highest figure of merit of 0.022 at 300 K was observed for the sample doped with 1 mol% Cu, obtained by the CAC method, and it was almost twice higher than in the undoped sample confirming the significant influence of Cu-doping with even small concentrations.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Journal of Alloys and Compounds",
title = "Mechanochemically assisted solid-state and citric acid complex syntheses of Cu-doped sodium cobaltite ceramics",
pages = "487-480",
volume = "640",
doi = "10.1016/j.jallcom.2015.04.003"
}

Perać, S., Savić, S. M., Branković, Z., Vrtnik, S., Dapčević, A.,& Branković, G.. (2015). Mechanochemically assisted solid-state and citric acid complex syntheses of Cu-doped sodium cobaltite ceramics. in Journal of Alloys and Compounds
Elsevier Science Sa, Lausanne., 640, 480-487.
https://doi.org/10.1016/j.jallcom.2015.04.003

Perać S, Savić SM, Branković Z, Vrtnik S, Dapčević A, Branković G. Mechanochemically assisted solid-state and citric acid complex syntheses of Cu-doped sodium cobaltite ceramics. in Journal of Alloys and Compounds. 2015;640:480-487.
doi:10.1016/j.jallcom.2015.04.003 .

Perać, Sanja, Savić, Slavica M., Branković, Zorica, Vrtnik, Stanislav, Dapčević, Aleksandra, Branković, Goran, "Mechanochemically assisted solid-state and citric acid complex syntheses of Cu-doped sodium cobaltite ceramics" in Journal of Alloys and Compounds, 640 (2015):480-487,
https://doi.org/10.1016/j.jallcom.2015.04.003 . .