Oxidative nonstoichiometry in perovskites, an experimental survey; the defect structure of an oxidized lanthanum manganite by powder neutron diffraction

Tofield, B.C.; Scott, Walter R. P.

doi:10.1016/0022-4596(74)90025-5

Cited by 406 publications

(157 citation statements)

References 21 publications

Supporting

Mentioning

143

Contrasting

Unclassified

Order By: Relevance

“…In so doing, the Mn oxidation state can be modified by introducing vacancies in either of both, cation or anion, sublattices. Actually, cation vacancies are created in LaMnO 3 , when treated under oxidizing atmosphere, in accordance to the La 1-t Mn 1-t O 3 formula [5,6]. This is possible because the perovskite structure does not admit interstitial oxygen and instead of that the system develops on the Mn and La vacancy formation.…”

Section: Introductionmentioning

confidence: 93%

See 1 more Smart Citation

Revisiting the Role of Vacancies in Manganese Related Perovskites

Ruiz‐González¹,

Cortés‐Gil²,

Alonso³

et al. 2007

TOICJ

View full text Add to dashboard Cite

Abstract:Oxygen engineering is an important tool for on-demand tailoring of manganese related perovskites into optimized performances. Anionic vacancies can be induced in both doped and undoped manganites by means of topotactic reduction processes under oxygen controlled atmosphere. This has given rise to the stabilization of new phases as a consequence of ordering of oxygen vacancies in which Mn 2+ appears due to the reducing process. Different reduction pathways are proposed for LaMnO 3 and doped systems. FM interactions remain at the octahedral layers when vacancies are longrange ordered. The peculiar magnetic behaviour of new layered perovskite superstructures is discussed.

show abstract

Section: Introductionmentioning

confidence: 93%

“…The La 0. 5 [34], which involves less orthorhombic distortion as a consequence of the bigger Sr size. Moreover, this involves Mn-OMn angles around 180º, which favours FM interactions by double exchange mechanism.…”

Section: La 1-x Sr X Mno 3-mentioning

confidence: 99%

Revisiting the Role of Vacancies in Manganese Related Perovskites

Ruiz‐González¹,

Cortés‐Gil²,

Alonso³

et al. 2007

TOICJ

View full text Add to dashboard Cite

show abstract

“…Very little is known about the non-stoichiometric properties of most of the mixed uranium oxides and this present study is directed towards one system of particular interest -BaUd 3 + x -which represents a relatively rare example of an O-excess perovskite. Tofield & Scott (1974) have investigated oxidative non-stoichiometry in perovskite systems, examining the range of excess O for LaMnO3+ x, LaVO3+ x, Sr(Laa+)TiO3+x, LaCrO 3, LaFeO 3 and EuTiO 3. The latter three systems did not show any tendency to oxidize and negligible solubility of La 3+ was observed in SrTiOa.…”

Section: Introductionmentioning

confidence: 99%

The preparation and structure of barium uranium oxide BaUO_3+x

Barrett¹,

Jacobson²,

Tofield³

et al. 1982

Acta Crystallogr Sect B

View full text Add to dashboard Cite

2775 moments are one-dimensional they are of finite length. Therefore, each chain consists of domains of parallel moments; the direction of the moments at each domain is antiparallel to the direction of the moments in its adjacent domains. The domain boundary point moves along the chain giving rise to the relaxation phenomenon. In the intermediate temperature range, as the temperature decreases the intrachain correlation length (size of the domain) increases until at T = T N = 9.5 K three-dimensional long-range order sets in. At this point the correlations along the ZC's increase to infinity and a long-range order between the ZC's sets in. At temperatures slightly above T N the ferromagnetic correlation within each chain, ferromagnetic domain, are of some finite length. Therefore, when the coupling between the chains sets in, it induces an emergence of a large contribution to the magnetic scattering at the Bragg angle as exhibited by the abrupt change in the magnetization curve (Fig. 3) AbstractThe structure of O-excess perovskite BaUO3+ x has been examined by powder neutron diffraction at room temperature. The non-stoichiometry is clearly shown to arise from an equivalent number of Ba and U vacancies in a compound of overall composition BaUOa.a0t3 ~. As expected, the temperature factors are larger in the disordered compound than in a compound close to the stoichiometric ideal of BaUO 3 which has also been structurally refined. A previous report that BaUO 3 is at least partially oxidized at room temperature in oxygen

show abstract

“…In fact, the oxygen sublattice is complete and the non-stoichiometry is realized by vacancy disordering of cationic A-and B-sublattices and from a structural point of view it is more correct to represent the formula of such manganite Ln 1-y Mn 1-y O 3 [14][15][16][17][18][19][20][21][22][23][24]. Another feature distinguishing Mn-containing systems, is an obvious area of homogeneity on the metal components Ln 1-x MnO 3 and LnMn 1-x O 3 [13,[25][26][27][28][29].…”

Section: Phase Equilibrium In Systems With T = Mnmentioning

confidence: 99%

Phase equilibria and thermodynamic properties of oxide systems on the basis of rare earth, alkaline earth and 3d-transition (Mn, Fe, Co) metals. A short overview of

et al. 2015

View full text Add to dashboard Cite

Phase equilibria and thermodynamic properties of oxide systems on the basis of rare earth, alkaline earth and 3d-transition (Mn, Fe, Co) metals. A short overview of.Review is dedicated studies of phase equilibria in the systems based on rare earth elements and 3d transition metals. It's highlighted several structural families of these compounds and is shown that many were found interesting properties for practical application, such as high conductivity up to the superconducting state, magnetic properties, catalytic activity of the processes of afterburning of exhaust gases, the high mobility in the oxygen sublattice and more.Keywords: phase equilibrium; manganites; isobaric-isothermal diagrams; solid solutions © Cherepanov V. A., Gavrilova L. Ya., Volkova N. E., Urusova A. S., Aksenova T. V., Kiselev E., 2015 IntroductionThe studies of phase equilibria in the systems based on rare earth elements and 3d transition metals and thermodynamic parameters of the oxide phases formed in these systems was initiated by Vladimir Mikhailovich Zhukovsky in 1977 under the direct supervision of Alexander Nikolaevich Petrov, as the development of contractual issues, conducted with an experienced company GIREDMET. The works on the study of the system Sm-Co-O and properties of oxide phases formed in system were then extended to other rare earth elements (REE) [1][2][3][4][5][6][7][8] and 3d transition metals [9][10][11][12][13]. A characteristic feature of these systems is the formation of oxide phases with perovskite structure AVO 3 and related. The partial substitution of rare earth elements in alkaline earth metals (AEM) leads to significant change of properties and they found a wide range of interesting for practical applications of the properties such as high conductivity up to the superconducting state, magnetic properties, catalytic activity of the processes of afterburning of exhaust gases and a variety of redox reactions, high mobility in the oxygen sublattice and more. In addition, partial substitution in the A-sublattice under constant 3d-cation in the systems Ln-T-O allows to stabilize the structure, which Cherepanov V. A., Gavrilova L. Ya., Volkova N. E., Urusova A. S., Aksenova T. V., Kiselev E. in the given conditions (temperature and oxygen pressure) are thermodynamically unstable. Therefore, further development of investigations of phase equilibria and thermodynamic stability of complex oxides were targeting the systems Ln-M-T-O (where Ln = REE, M = Ca, Sr, Ba; T = Mn, Fe, Co, Ni, Cu). When a certain percentage of similarity (in all possible formation of a phase with perovskite structure LnTO 3±d ) these systems still have a noticeable and distinctive features depending on the nature of the components. Phase equilibrium in systems with T = MnThe significant difference of perovskite phases in the manganese-containing systems Ln-Mn-O is that the oxygen content in them exceeds the stoichiometric air LnMnO 3+d . In fact, the oxygen sublattice is complete and the non-stoichiometry is realized by vacancy disordering ...

show abstract

Oxidative nonstoichiometry in perovskites, an experimental survey; the defect structure of an oxidized lanthanum manganite by powder neutron diffraction

Cited by 406 publications

References 21 publications

Revisiting the Role of Vacancies in Manganese Related Perovskites

Revisiting the Role of Vacancies in Manganese Related Perovskites

The preparation and structure of barium uranium oxide BaUO_3+x

Phase equilibria and thermodynamic properties of oxide systems on the basis of rare earth, alkaline earth and 3d-transition (Mn, Fe, Co) metals. A short overview of

Contact Info

Product

Resources

About

Oxidative nonstoichiometry in perovskites, an experimental survey; the defect structure of an oxidized lanthanum manganite by powder neutron diffraction

Cited by 406 publications

References 21 publications

Revisiting the Role of Vacancies in Manganese Related Perovskites

Revisiting the Role of Vacancies in Manganese Related Perovskites

The preparation and structure of barium uranium oxide BaUO3+x

Phase equilibria and thermodynamic properties of oxide systems on the basis of rare earth, alkaline earth and 3d-transition (Mn, Fe, Co) metals. A short overview of

Contact Info

Product

Resources

About

The preparation and structure of barium uranium oxide BaUO_3+x