An off-center ion near a Ba site in BaTiO3 as studied by EPR under uniaxial stress

Lenjer, S.; Scharfschwerdt, Raphaela; Kool, Th. W.; Schirmer, O. F.

doi:10.1016/s0038-1098(00)00307-0

Cited by 14 publications

(12 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The lines observed in EPR spectra have been attributed to the Ni + ions at the B sites, 22 off-center Ni + ions at the A sites. 23 In Ref. 17, EPR studies of Ni-doped hexagonal BaTiO 3 have found Ni 3+ ions that replaces Ti 4+ in two different positions (Ti(1) and Ti(2)); however, these centers can be associated with a maximum of 5% of the nominal amount of nickel, i.e.…”

Section: Introductionmentioning

confidence: 99%

On the nature of change in Ni oxidation state in BaTiO₃–SrTiO₃system

Лебедев

Sluchinskaya

2016

Ferroelectrics

View full text Add to dashboard Cite

XAFS studies of Ni-doped Ba1−xSrxTiO3 solid solution reveal that the Ni oxidation state changes from 4 in SrTiO3 to 2.5 in BaTiO3 when varying x. This change is accompanied by a noticeable change in the interatomic Ni-O distances in the first shell. The first-principles calculations show that nickel creates an impurity band in the forbidden band gap of BaTiO3 and SrTiO3, which explains the appearance of intense absorption of Ni-doped samples in the visible region. The analysis of the electronic structure of doped crystals and calculations of the oxygen vacancy formation energy in them show that different oxidation states of Ni in SrTiO3 and BaTiO3 can be explained by different formation energies of the oxygen vacancies in these compounds.

show abstract

Section: Introductionmentioning

confidence: 99%

On the nature of change in Ni oxidation state in BaTiO₃–SrTiO₃system

Лебедев

Sluchinskaya

2016

Ferroelectrics

View full text Add to dashboard Cite

show abstract

“…It was considered that the difference of the Ti 3d electronic states gives the characteristic properties of the electricity in BaTiO 3 and SrTiO 3 . More recently, Kohne et al [17] and Lenjer et al [18,19], using electron paramagnetic resonance (EPR) below 20 K under applied uniaxial stress, reported that there are conductive Ti 3+ Jahn-Teller polarons in pure BaTiO 3 , but not in pure SrTiO 3 . Therefore, we deduced in a lowtemperature region that the Ti 3d electrons induced near the Fermi level (E F ) by the hybridization Ti 3d n L m may be conductive in the top region of the O 2-2p valence band in BaTiO 3 , but not in SrTiO 3 , as others have reported [17 -19].…”

Section: Discussionmentioning

confidence: 99%

Correlation between ferroelectricity and electronic density of states near the Fermi level in BaTiO₃

Hidaka¹,

Tokiwa

Takahashi

et al. 2004

Physica Status Solidi (b)

View full text Add to dashboard Cite

The electronic density of states in BaTiO 3 is studied by means of X-ray absorption near-edge structure in a vicinity of a Ti K edge and Ba L edges. A 4pπ band of the Ti ion and a 5dπ band of the Ba ion having a high-density unoccupied state occupy a level just above the Fermi level (E F ). The pre-edge peaks give that, in addition to an O 2-2p valence band, the electronic density of states below E F are composed of negativecharge-transfer bands 3d 2 bands in the ferroelectric phase suggests that the collective displacement of Ba ions from ideal ionic sites of the cubic perovskite-type structure reduces the hybridization between the Ba and O ions. This gives that the effective charge on the O ions is increased and induces a large dipole moment between the O ions and the Ti ions, which are at an off-center position of TiO 6 octahedra in the ferroelectric phase.

show abstract

“…The lines observed in the EPR spectra were ascribed either to Ni + ions at the B sites 23 or to off-center Ni + ions at the A sites. 24 In the EPR studies of nickel-doped hexagonal BaTiO 3 , 18 Ni 3+ ions substituting for Ti 4+ ions in two different positions (Ti(1) and Ti(2)) were found. However, the concentration of these centers was less than 5% of the nominal amount of nickel; i.e., most of the Ni ions in the sample were in the EPR-inactive state.…”

Section: Introductionmentioning

confidence: 95%

An experimental and theoretical study of Ni impurity centers in Ba0.8Sr0.2TiO3

Sluchinskaya

Лебедев

2017

Phys. Solid State

View full text Add to dashboard Cite

The local environment and the charge state of a nickel impurity in cubic Ba0.8Sr0.2TiO3 are studied by XAFS spectroscopy. According to the XANES data, the mean Ni charge state is ∼2.5+. An analysis of the EXAFS spectra and their comparison with the results of first-principle calculations of the defect geometry suggest that Ni 2+ ions are in a high-spin state at the B sites of the perovskite structure and the difference of the Ni 2+ and Ti 4+ charges is mainly compensated by distant oxygen vacancies. In addition, a considerable amount of nickel in the sample is in a second phase BaNiO 3−δ . The measurements of the lattice parameter show a decrease in the unit cell volume upon doping, which can indicate the existence of a small amount of Ni 4+ ions at the B sites.

show abstract

An off-center ion near a Ba site in BaTiO3 as studied by EPR under uniaxial stress

Cited by 14 publications

References 18 publications

On the nature of change in Ni oxidation state in BaTiO₃–SrTiO₃system

On the nature of change in Ni oxidation state in BaTiO₃–SrTiO₃system

Correlation between ferroelectricity and electronic density of states near the Fermi level in BaTiO₃

An experimental and theoretical study of Ni impurity centers in Ba0.8Sr0.2TiO3

Contact Info

Product

Resources

About

An off-center ion near a Ba site in BaTiO3 as studied by EPR under uniaxial stress

Cited by 14 publications

References 18 publications

On the nature of change in Ni oxidation state in BaTiO3–SrTiO3system

On the nature of change in Ni oxidation state in BaTiO3–SrTiO3system

Correlation between ferroelectricity and electronic density of states near the Fermi level in BaTiO3

An experimental and theoretical study of Ni impurity centers in Ba0.8Sr0.2TiO3

Contact Info

Product

Resources

About

On the nature of change in Ni oxidation state in BaTiO₃–SrTiO₃system

On the nature of change in Ni oxidation state in BaTiO₃–SrTiO₃system

Correlation between ferroelectricity and electronic density of states near the Fermi level in BaTiO₃