Research output: Contribution to journal › Article › peer-review
Magnetic and electric properties, ESR, XPS and NEXAFS spectroscopy of CaCu3Ti4O12 ceramics. / Zhuk, N. A.; Nekipelov, S. V.; Sivkov, V. N.; Sekushin, N. A.; Lutoev, V. P.; Makeev, B. A.; Koroleva, A. V.; Fedorova, A. V.; Koksharova, L. A.; Ignatova, M. M.; Korolev, R. I.
In: Ceramics International, Vol. 46, No. 13, 09.2020, p. 21410-21420.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Magnetic and electric properties, ESR, XPS and NEXAFS spectroscopy of CaCu3Ti4O12 ceramics
AU - Zhuk, N. A.
AU - Nekipelov, S. V.
AU - Sivkov, V. N.
AU - Sekushin, N. A.
AU - Lutoev, V. P.
AU - Makeev, B. A.
AU - Koroleva, A. V.
AU - Fedorova, A. V.
AU - Koksharova, L. A.
AU - Ignatova, M. M.
AU - Korolev, R. I.
PY - 2020/9
Y1 - 2020/9
N2 - ESR, XPS and NEXAFS spectra, as well as magnetic and electric properties of CaCu3Ti4O12 synthesized by the solid-phase method within 6,12,24,48 and 60 h were studied. The analysis of magnetic susceptibility of CaCu3Ti4O12 and magnesium-containing solid solutions of CaCu3-3xMg3xTi4O12 revealed antiferromagnetic exchange interactions between Cu paramagnetic atoms, while the effective magnetic moment of copper atoms corresponds to the electronic state of Cu(II). In CaCu3Ti4-4хMg4хO12-δ samples within the whole concentration range the impurity phase MgTiO3 was observed. The magnetic properties of calcium copper titanate were found to be inconsistent depending on the synthesis duration. The extreme point of magnetic susceptibility was found among samples synthesized within 48 h. Modelling and interpretation of the XPS spectra of CaCu3Ti4O12 were performed. Based on the NEXAFS and XPS spectroscopy data, copper and calcium atoms in ceramics display oxidation state +2, while titanium atoms – Ti(IV). ESR spectra of CaCu3Ti4O12 samples show an exchange-narrowing signal from copper (II) atoms at g = 2.15. In the ESR spectra of CaCu3-3xMg3xTi4O12 the only intense exchange-narrowed line of Lorentzian form of Cu2+ ions is observed. The impedance spectroscopy study of electric properties of CaCu3Ti4O12 found the media to feature temperature-dependent reach-through conductivity with activation energy of 0.79–0.71 eV. At 255–300°С, the dominant polarization process is in line with the Gerischer model. It indicates the formation of anionic-cationic associates accompanied by decreased low-frequency capacitance of the samples. With temperatures of over 300°С the samples start displaying ion-migrating polarization which contributes to higher capacitance and dielectric loss at low frequencies. As the temperature grows further to 400°С, the ion migration process gets to dominate within the whole frequency range under study. Based on the study, a conclusion was made on movable cations of copper participating in the polarization process at room temperature.
AB - ESR, XPS and NEXAFS spectra, as well as magnetic and electric properties of CaCu3Ti4O12 synthesized by the solid-phase method within 6,12,24,48 and 60 h were studied. The analysis of magnetic susceptibility of CaCu3Ti4O12 and magnesium-containing solid solutions of CaCu3-3xMg3xTi4O12 revealed antiferromagnetic exchange interactions between Cu paramagnetic atoms, while the effective magnetic moment of copper atoms corresponds to the electronic state of Cu(II). In CaCu3Ti4-4хMg4хO12-δ samples within the whole concentration range the impurity phase MgTiO3 was observed. The magnetic properties of calcium copper titanate were found to be inconsistent depending on the synthesis duration. The extreme point of magnetic susceptibility was found among samples synthesized within 48 h. Modelling and interpretation of the XPS spectra of CaCu3Ti4O12 were performed. Based on the NEXAFS and XPS spectroscopy data, copper and calcium atoms in ceramics display oxidation state +2, while titanium atoms – Ti(IV). ESR spectra of CaCu3Ti4O12 samples show an exchange-narrowing signal from copper (II) atoms at g = 2.15. In the ESR spectra of CaCu3-3xMg3xTi4O12 the only intense exchange-narrowed line of Lorentzian form of Cu2+ ions is observed. The impedance spectroscopy study of electric properties of CaCu3Ti4O12 found the media to feature temperature-dependent reach-through conductivity with activation energy of 0.79–0.71 eV. At 255–300°С, the dominant polarization process is in line with the Gerischer model. It indicates the formation of anionic-cationic associates accompanied by decreased low-frequency capacitance of the samples. With temperatures of over 300°С the samples start displaying ion-migrating polarization which contributes to higher capacitance and dielectric loss at low frequencies. As the temperature grows further to 400°С, the ion migration process gets to dominate within the whole frequency range under study. Based on the study, a conclusion was made on movable cations of copper participating in the polarization process at room temperature.
KW - Calcium copper titanate
KW - ESR
KW - Magnetic and electric properties
KW - XPS and NEXAFS spectroscopy
KW - THIN-FILMS
KW - ELECTROCHEMICAL PROPERTIES
KW - CCTO
KW - BEHAVIOR
KW - TITANATES
KW - GIANT DIELECTRIC-CONSTANT
KW - OXYGEN
KW - RESPONSES
KW - SINTERING CONDITIONS
KW - MICROSTRUCTURE
UR - http://www.scopus.com/inward/record.url?scp=85085607077&partnerID=8YFLogxK
UR - https://www.mendeley.com/catalogue/7c26827f-a380-3a68-bcb7-7e551564cf88/
U2 - 10.1016/j.ceramint.2020.05.239
DO - 10.1016/j.ceramint.2020.05.239
M3 - Article
AN - SCOPUS:85085607077
VL - 46
SP - 21410
EP - 21420
JO - Ceramics International
JF - Ceramics International
SN - 0272-8842
IS - 13
ER -
ID: 61137756