Quasicrystal Approximants

Abstract

The concept of quasicrystal approximants is best pursued with reference to the quasicrystals themselves. This makes the classification of approximants into classes congruent to those for quasicrystals useful, that is, axial and icosahedral. As noted by several authors, work on approximants has come full circle; the initial interest in approximants grew out of a desire to understand particularly the enigmatic structure of the quasicrystals, but lately it has become increasingly clear that not only the structure but also many of the physical properties of quasicrystals may be more conveniently probed and understood through the study of their approximants. Although the uniqueness of quasicrystals lies in their structures, the approximants approximate this to such an extent that most questions about quasicrystals can be addressed through the proxy of the approximant phases. This treatise deals mainly with the structural properties of approximants.

Synthesis and Characterization of LaNi0.5Ti0.5O3 and La2NiTiO6 Double Perovskite Nanoparticles

“…The symmetry and space group are according to that reported in the literature for the LaNi 0.5 Ti 0.5 O 3 [ 11 ] (Sample 1 and Sample 2) and La 2 NiTiO 6 [ 12 , 13 , 14 ] (Sample 3). The Glazer notation for as-synthesized materials is a − a − c + , as reported for the case of the orthorhombic [ 19 ] and monoclinic [ 26 ] symmetries. Verification of the crystal structure was performed from the indexation of each XRD pattern, using McMaille software [ 27 ], with calculations reported in Figures S3–S8 of the Supplementary Material .…”