Molybdates of the form AMoO 4 (A = Ca, Sr, Ba, Pb) are widely studied materials due
to their photo-luminescence properties. In the present doctoral thesis, we analyze the effect of
oxygen vacancies through density functional density (DFT) in these scheelite-type materials,
aiming primarily at the possible ferromagnetism induced due to this kind of defect. The spin-
polarized band structure spectrum shows the appearance of narrow bands within the band gap
for the spin-up channel. In BaMoO 4 -V O × , SrMoO 4 -V O × , and PbMoO 4 -V O × a resultant magnetic
moment of 2µ B per cell is observed due to, the electrons once bonded with O being trapped
by the 4d states in trigonal cluster MoO 3 , while in CaMoO 4 -V O × , the oxygen vacancy distort
the lattice, so that crystal field splitting results in a low spin case with the resultant magnetic
moment of 0.15µ B per cell. This study also provides a valuable tool for lowering the band
gap in these materials, since the wide band gap has been recognized as a challenging factor for
infrared and visible light photocatalysis performance. We calculated the mechanical properties
from elastic constants such as bulk, shear, and Young modulus. In addition, Vicker’s hardness
indicates that oxygen vacancy increases the hardness of these materials. For thermoelectric
properties, the electrical conductivity is addressed to the n-type carrier and, allied with the low
thermal conductivity (lattice + electronic) provided by phonon scattering, results in a high figure
of merit for all defective scheelites.
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