Defect association in acceptor-doped SrTiO₃: case study for Fe′TiV˙˙O and Mn″TiV˙˙O

Spectroscopic study of the electric field induced valence change of Fe-defect centers in SrTiO3

“…The EPR signal of the cathodic region consists of two structurally non-equivalent centers, a cubic center equivalent to that in the anodic region and an axial center with a strongly anisotropic g-factor, as is well described in the literature. 23,24 Kirkpatrick et al 23 found these lines with g > = 5.993 and g || = 2.0054 to correspond to the À1/2 2 1/2 transition of Fe 3+ in an axial site with a strong tetragonal distortion. No other lines are visible due to the strong zero-field splitting induced by the local crystal field.…”

“…This suggests that the formation of Fe 3+ À V Ö complexes is favored by the minimization of strain energy in the crystal in addition to the association enthalpy. 24 Above the dilute limit, the reduced distance between Fe-centers provides some strain relaxation which results in smaller Fe-O distances even in the reduced material. 17 These considerations enable the determination of the Fe valence state in the dilute regime based on the X-ray absorption characteristics.…”

“…The experimental determination of the Fe 3+ À V Ö concentration has been shown to be possible via double-integration EPR techniques, 24 and also attempted via linear combination of XANES spectra. 8 In principle, the relative concentrations of Fe centers can be estimated from linear combination of the Fe-O bond distances using suitable standards.…”

The role of oxygen vacancy in the photoluminescence property at room temperature of the CaTiO3

“…31,32 Mestric et al 33 considered the presence of six positions for an oxygen vacancy in ZrO 6 . It could not be proven experimentally that only six distinct centers are involved.…”

Influence of defect mobility on electrostrain in acceptor-doped Ba0.80Sr0.20TiO3

“…As defect dipole symmetry attains the crystal symmetry in aged specimens 5, 9, 10 Electron Paramagnetic Resonance (EPR) spectroscopy was employed as structural probe for understanding the defect symmetry. [11][12][13][14] In the case of Fe 3+ -doped system, as a result of very high internal electric field (E i ), 7 […”