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      https://www.ias.ac.in/article/fulltext/pram/071/05/0935-0940

    • Keywords

       

      Neutron diffraction; X-ray diffraction; Rietveld refinement; crystal structure; ferroelectric; bismuth titanates.

    • Abstract

       

      Here we report the results of combined powder X-ray and neutron diffraction studies of Bi$_{4−x}$Nd$_{x}$Ti3O12 $(0.0 \leq x \leq 2.0)$ compositions. The parent Bi4Ti3O12 has an orthorhombic lattice (space group: B2cb) with unit cell parameters $a$ = 5.4432(5) Å, $b$ = 5.4099(5) Å and $c$ = 32.821(2) Å, and $V$ = 966.5(1) Å3. This orthorhombic lattice is retained in all the studied compositions. The unit cell parameters gradually decrease with Nd 3+ ion concentration with a discontinuity at $x = 0.75$. Orthorhombicity of the lattice decreases with increase in Nd3+ content in the lattice. The orthorhombic unit cell parameters for a representative Bi2Nd2Ti3O12 composition are: $a$ = 5.3834(9), $b$ = 5.3846(9) and $c$ = 32.784(1) Å. The observed orthorhombic distortion at $x$ = 2.0 is very small and thus the crystal structure apparently has a pseudo-tetragonal lattice. In addition, Nd3+ preferentially substitutes in the perovskite slab of the Aurivillius structure. The fraction of Nd3+ in the fluorite slab increases with increase in Nd3+ contents.

    • Author Affiliations

       

      S N Achary1 S J Patwe1 P S R Krishna2 A B Shinde2 A K Tyagi1

      1. Chemistry Division; Bhabha Atomic Research Centre, Mumbai 400 085, India
      2. Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
    • Dates

       
  • Pramana – Journal of Physics | News

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