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arXiv · 1001.2227

Polar behavior of double perovskite (Bi,Pb)ZnNbO6 and (Bi,Sr)ZnNbO6: Density functional calculations

S. Takagi·A. Subedi·D. J. Singh·V. R. Cooper
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Abstract

The polar behavior of double perovskite (Bi,Pb)ZnNbO$_6$ and (Bi,Sr)ZnNbO$_6$ was investigated using first principles density functional calculations within the local density approximation. These materials have both $A$-site size disorder and ions with sterochemical activity. We found a strong ferroelectric distortion in both materials. The polarization of the Pb material is $>$80 $μ$C/cm$^2$ along the rhombohedral direction and the Sr based material is only slightly inferior. The high polarization results mainly from a large off-centering of Bi and the large Born effective charge of Nb, which yields a large contribution polarization although the Nb off-centers by a smaller amount. Neither of these materials favors a tetragonal state, and therefore solid solutions with PbTiO$_3$ may show morphotoropic phase boundaries.

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S. Takagi, A. Subedi, D. J. Singh, V. R. Cooper. 2010-01-13. Polar behavior of double perovskite (Bi,Pb)ZnNbO6 and (Bi,Sr)ZnNbO6: Density functional calculations. https://doi.org/10.1103/physrevb.81.134106

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