Speaker
Ariste Bolivard Voufack
(Université de Lorraine, Vandœuvre-lès-Nancy, France)
Description
The study and the understanding of both physical and chemical properties of
inorganic materials remain a perpetual challenge. In the present work, the modelling
of charge densities of both paramagnetic and ferromagnetic perovskite structure of
YTiO 3 is undertaken. The structural analysis of this inorganic compound in these two
magnetic phases showed that the shape of Ti octahedron is irregular expressing the
interactions between electron of Ti atom and O atoms of its environment. The charge
density around Ti atom changes significantly between paramagnetic and
ferromagnetic phases. The spin-split multipolar model is used in the frame of a joint
refinement of X-ray (XRD) and polarization neutron (PND) diffraction data [1] in
ferromagnetic phase. The experimental distributions of alpha and beta spin electrons
is obtained and their representation agrees with the orbital ordering suggested by
previous work of Ito et al. [2] and Hichikawa et al. [3, 4] from X-ray magnetic
diffraction (XMD) and PND respectively. Its ferromagnetic order is due to the
presence of an unpaired electron localized on Ti atom. The spin density distribution
shows the shape of t 2g orbital for the unpaired electron. Furthermore, the provided
modelling of charge density shows a charge depletion around Ti atom towards the O
atoms described by e g orbitals, meanwhile an accumulation of the density in bisecting
directions expresses the t 2g orbitals. Theoretical calculations based on density
functional theory (DFT) methods were also carried out and a comparison with these
results will be done.
[1] Deutsch M. et al., IUCrJ , 1,194—199, 2014.
[2] Ito M. et al., Journal of Physics and Chemistry of Solids, 65, 1993—1997, 2004.
[3] Ichikawa H. et al., Physica B, 281, 482—484, 2000.
[4] Kibalin I. A. et al., Phys. Rev. B 96, 054426, 2017.
Primary author
Ariste Bolivard Voufack
(Université de Lorraine, Vandœuvre-lès-Nancy, France)
