Nonstoichiometry and thermochemical stability of the perovskite-type La1−xSrxMnO3−δ

Mizusaki, Junichiro; Tagawa, Hiroaki; Naraya, Kazunori; Sasamoto, Tadashi

doi:10.1016/0167-2738(91)90076-n

Cited by 173 publications

(96 citation statements)

References 14 publications

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“…The electron transport-related properties of the manganites are associated with the simultaneous presence in their structure of manganese cations in different charged states that appear in response to heterovalent doping and oxygen loss. One of the powerful tools to understand the ensuing defect structure in the manganites is the analysis of the plots of oxygen nonstoichiometry δ vs. oxygen partial pressure p O 2 at different temperatures T, the so-called p O 2 -Т-δ diagrams [7][8][9][10][11][12][13][14]. For instance, it is shown that the equilibrium of manganese species in La 1−x А x MnO 3−δ at х ≤0.5 depends strongly on charge disproportionation reaction 2Mn 3+ =Mn 2+ +Mn 4+ [10,11,13,14].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics of oxygen in CaMnO3 − δ

Goldyreva

Леонидов

Патракеев

et al. 2013

J Solid State Electrochem

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The experimental data for equilibrium oxygen content were used in order to extract increments of partial molar thermodynamic functions of oxygen with changes of oxygen stoichiometry in calcium manganite CaMnO 3−δ . It is shown that along with the oxygen exchange reaction, thermal excitation of Mn 4+ cations plays an important role in equilibration of charged manganese species that appear in response to the loss of oxygen at heating. The interrelation of partial molar enthalpy and entropy of oxygen with electron and ion defect formation parameters is obtained in approximation of the point defect model. The nearly linear changes of oxygen partial molar enthalpy are shown to directly reflect thermally driven changes in concentration of Mn 3+ cations.

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Section: Introductionmentioning

confidence: 99%

Thermodynamics of oxygen in CaMnO3 − δ

Goldyreva

Леонидов

Патракеев

et al. 2013

J Solid State Electrochem

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“…• C in a tube with a flow of air [8]. In [9] citrates of La and Mn are used as precursors for LaMnO 3 -ammonia solutions of La(C 6 H 5 O 7 ).nH 2 O and Mn(C 6 H 5 O 7 ).H 2 O are mixed in an equimolar La: Mn ratio and at heating dark-red precipitate is formed, supposed to be a mixed-metal citric complex.…”

Section: Introductionmentioning

confidence: 99%

“…The synthesis of a single-phase product is often difficult and usually the particles of the final product are inhomogeneous in shape and size. Because of this, numerous methods for low-temperature synthesis have been proposed [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Coprecipitation of the metal nitrates solutions with aqueous ammonium carbonate is used in [5].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of Mn-, La-Mn- and La-Ca-Mn-citrates as precursors for LaMnO3 and La1−xCaxMnO3

Petrova

Todorovsky

Vasileva³

2005

Open Chemistry

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Mn-, LaMn-and LaCaMn-citrates were synthesized at 60-120 • C in ethylene glycol medium using chlorides or nitrates as metal sources. Their composition, IR spectra and thermal decomposition were studied. Equimolar La/Mn ratio has been established in the complex, prepared from chloride solution with the same initial composition of the metals. In the isolated three-metallic complex the molar ratio of the metals deviates from the composition in the initial solution. The final products of the heating of Mn-and mixed-metal LaMn-citrates at 1000 • C are phase-homogeneous Mn 3 O 4 (hausmannite) and LaMnO 3 respectively. Parasitic phase(s) are observed in La x Ca 1−x Mn y O 3 , produced from LaCaMn-citrate.

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“…The ordering of cations in the A-sublattice Ln 0. 33 [70,71]. Another confirmation of the relationship of the structure and content of oxygen may be the results of determining the oxygen non stoichiometry and structural analysis as a function of temperature for Sr 2 LaFe 3 O 8+y [68].…”

Section: Phase Equilibrium In Systems With T = Fementioning

confidence: 74%

“…A significant reduction of oxygen content in the first stage reduction of pressure (0.21-10 -9 атм ) [14,33] leads to the possibility of increasing content of strontium in boundary composition (x). With further decreasing oxygen pressure 10 -9 -10 -13 атм loss of oxygen by solid solution slows down, the dependence d = f(Po 2 ) reaches a plateau [14,33] and the decrease of the degree of oxidation of manganese is achieved by reducing the solubility of strontium in La 1-x Sr x MnO 3-d . Enriched with strontium solid solutions La 1−x Sr x MnO 3−(0.5+x)/2 (0.67 ≤ x ≤ 1) with oxygen vacancies ordered in a 6-layer perovskite-like structure, at low oxygen activity (in the presence of NaH) and at low temperatures (not higher than 400 °C) are described in [34].…”

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

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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 ...

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Nonstoichiometry and thermochemical stability of the perovskite-type La1−xSrxMnO3−δ

Cited by 173 publications

References 14 publications

Thermodynamics of oxygen in CaMnO3 − δ

Thermodynamics of oxygen in CaMnO3 − δ

Synthesis and characterization of Mn-, La-Mn- and La-Ca-Mn-citrates as precursors for LaMnO3 and La1−xCaxMnO3

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

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