This article is cited in 6 papers

Proceedings of the XIX All-Russian Conference on Physics of Ferroelectrics (VKS-XIX) (Moscow, Russia, June 19-23, 2011

XAFS studies of the local structure and charge state of the Pr impurity in SrTiO$_3$

I. A. Sluchinskaya^a, A. I. Lebedev^a, A. I. Erko<sup>b

a</sup> Lomonosov Moscow State University
^b BESSY, Berlin, Germany

Abstract: Solid solutions of (Sr$_{1-x}$Pr$_x$)TiO$_3$ have been studied using X-ray methods. It has been shown that, with an increase in the praseodymium concentration, the temperature of the structural phase transition to the phase with space group $I4/mcm$ increases and, at $x\ge$ 0.15, the structure at 300 K is tetragonal. X-ray absorption fine structure (XAFS) spectroscopy studies have revealed that Pr ions are predominantly in the charge state 3+ and occupy the Sr sites. No indications of the off-centering of Pr atoms at the Sr sites have been revealed. The local environment of Pr atoms is characterized by a strong relaxation of the oxygen atoms, the value of which corresponds to the difference between the ionic radii of PrSr$^{3+}$ and SrSr$^{2+}$. It has been found that, in the second shell, there occurs a significant repulsion of the PrSr$^{3+}$ and TiSr$^{4+}$ ions, which is responsible for the weak dependence of the lattice parameter in the solid solution on the praseodymium concentration.

 English version: Physics of the Solid State, 2012, 54:5, 975–979

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