International Conference Physics.SPb/2023 October 23-27, 2023, St. Petersburg
Spectroscopy of condensed state

Effect of doping with iron and magnesium on high-temperature stability and physicochemical properties of bismuth tanalates

S. V. Nekipelov^ab, N. A. Zhuk^b, M. G. Krzhizhanovskaya^c, V. N. Sivkov<sup>a

a</sup> Komi Scientific Center of Ural Branch of RAS, Syktyvkar, Russia
^b Syktyvkar State University, 167001 Syktyvkar, Russia
^c Saint Petersburg State University, St. Petersburg, Russia

Abstract: Bismuth tantalum pyrochlores doped with iron and magnesium atoms were obtained thermally stable up to a temperature of 1140$^\circ$C: Bi$_2$Mg$_x$Fe$_{1-x}$Ta$_2$O$_{9.5-\Delta}$ ($x$ = 0–1). The effect of Fe and Mg codoping on their crystal structure has been studied. The unit cell parameter of solid solutions increases uniformly from 10.4871(2) $\mathring{\mathrm{A}}$ ($x$ = 0) to 10.54607 $\mathring{\mathrm{A}}$ ($x$ = 1). According to the XPS and NEXAFS spectroscopy data, it was found that the ions in these solid solutions are in the charge states Bi(+3), Mg(+2), Fe(+3), Ta(+5-$\delta$). The dopant atoms iron and magnesium are introduced into the positions of the tantalum atom without distorting the symmetry of the crystal lattice.

Keywords: bismuth tantalates, pyrochlores, XPS, NEXAFS.

Received: 11.05.2023
Revised: 03.07.2023
Accepted: 30.10.2023

DOI: 10.61011/OS.2023.11.57002.4917-23

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