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This article is cited in 4 scientific papers (total in 4 papers)
Dielectrics
Paramagnetic mn antisite defects in nanoceramics of aluminum–magnesium spinel
A. F. Zacepina, A. N. Kiryakova, D. R. Bajtimirova, T. V. D'yachkovab, A. P. Tyutyunnikb, Yu. G. Zainulinb a Ural Federal University, Ekaterinburg
b Institute of Solid State Chemistry, Urals Branch of the Russian Academy of Sciences, Ekaterinburg
Abstract:
The effect of structure and size parameters on the formation of intrinsic and impurity paramagnetic centers in nanoceramics of aluminum–magnesium spinel is studied. The studied samples (grain size $\sim$ 30 nm) are obtained by thermobaric synthesis. Microcrystalline ceramics and MgAl$_{2}$O$_{4}$ single crystal are used as the reference samples. Characteristic paramagnetic centers of Mn$^{2+}$ (hyperfine structure constant (HFS) $A$ = 82 G) are present in both single crystal and microceramics. In the studied samples of nanoceramics in the initial state, both impurity Mn$^{2+}$ and intrinsic F$^+$ centers exist. Unlike the nanoceramics, the centers of F$^+$ type in the reference sample appear only after the irradiation with accelerated electrons (130 keV). The parameters of Mn$^{2+}$ centers in nanoceramics significantly differ on that in microceramics and single crystal. EPR signal of Mn$^{2+}$ centers in nanoceramics is characterized by two anomalous constant HFS ($A_1$ = 91.21 G, $A_2$ = 87.83 G) caused by two types of octahedrally coordinated manganese ions
([Mn$^{2+}$]$_{\mathrm{Al}^{3+}}$ antisite defects). The features of spectral parameters of manganese centers correlate with a decrease in the cell parameter of MgAl$_{2}$O$_{4}$ in the nanostructural state. The observed effects are interpreted based on the assumed scheme of [Mn$^{2+}$]$_{\mathrm{Al}^{3+}}$ charge compensation by the aluminum antisite defect and F$^+$ center.
Keywords:
electron paramagnetic resonance, MgAl$_{2}$O$_{4}$, nanoceramics, microceramics, hyperfine structure, antisite defects.
Received: 16.08.2019 Revised: 16.08.2019 Accepted: 03.09.2019
Citation:
A. F. Zacepin, A. N. Kiryakov, D. R. Bajtimirov, T. V. D'yachkova, A. P. Tyutyunnik, Yu. G. Zainulin, “Paramagnetic mn antisite defects in nanoceramics of aluminum–magnesium spinel”, Fizika Tverdogo Tela, 62:1 (2020), 94–100; Phys. Solid State, 62:1 (2020), 137–143
Linking options:
https://www.mathnet.ru/eng/ftt8528 https://www.mathnet.ru/eng/ftt/v62/i1/p94
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