Electrical Properties of the Ferrite SrFeOy at High Temperatures

Кожевников, В. Л.; Леонидов, И. А.; Патракеев, М.В.; Митберг, Э. Б.; Poeppelmeier, Kenneth R.

doi:10.1006/jssc.2001.9120

Cited by 111 publications

(90 citation statements)

References 14 publications

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“…27,28,32 P-type (in air) and n-type (reducing conditions) semiconductor behaviour has previously been reported for several related Fe-containing perovskites, including La 1Àx Sr x FeO 3Àd [33][34][35] and LnFeO 3 (Ln = Pr, Nd, Sm, Eu and Gd). 36,37 In these materials the electronic conductivity is strongly linked to polaron hopping and the oxidation state of Fe, which is strongly dependent on the partial pressure of oxygen ( p(O 2 )).…”

Section: +mentioning

confidence: 85%

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Electrical conductivity and thermopower of (1 − x) BiFeO₃– xBi_0.5K_0.5TiO₃(x = 0.1, 0.2) ceramics near the ferroelectric to paraelectric phase transition

Wefring

Einarsrud

Grande

2015

Phys. Chem. Chem. Phys.

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Ferroelectric BiFeO 3 has attractive properties such as high strain and polarization, but a wide range of applications of bulk BiFeO 3 are hindered due to high leakage currents and a high coercive electric field.Here, we report on the thermal behaviour of the electrical conductivity and thermopower of BiFeO 3 substituted with 10 and 20 mol% Bi 0.5 K 0.5 TiO 3 . A change from p-type to n-type conductivity in these semi-conducting materials was demonstrated by the change in the sign of the Seebeck coefficient and the change in the slope of the isothermal conductivity versus partial pressure of O. A minimum in the isothermal conductivity was observed at B10 À2 bar O 2 partial pressure for both solid solutions. The strong dependence of the conductivity on the partial pressure of O 2 was rationalized by a point defect model describing qualitatively the conductivity involving oxidation/reduction of Fe 3+ , the dominating oxidation state of Fe in stoichiometric BiFeO 3 . The ferroelectric to paraelectric phase transition of 80 and 90 mol% BiFeO 3 was observed at 648 AE 15 and 723 AE 15 1C respectively by differential thermal analysis and confirmed by dielectric spectroscopy and high temperature powder X-ray diffraction.

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Section: +mentioning

confidence: 85%

“…[33][34][35][36][37] The electrical conductivity of these materials has previously been modelled with success by a mass action type treatment of point defect equilibria. A mass action type model adapted for 0.8BFO and 0.9BFO is introduced here based on the approach presented by Mizusaki et al 35 for LaFeO 3 .…”

Section: Discussionmentioning

confidence: 99%

Electrical conductivity and thermopower of (1 − x) BiFeO₃– xBi_0.5K_0.5TiO₃(x = 0.1, 0.2) ceramics near the ferroelectric to paraelectric phase transition

Wefring

Einarsrud

Grande

2015

Phys. Chem. Chem. Phys.

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“…1), and can be considered as an oxygen-deficient perovskite where the oxygen vacancies are ordered along (0 1 0) planes [11]. These vacancies were assumed to significantly contribute to ionic transport, forming one-dimensional diffusion pathway for oxygen ion migration in the tetrahedral layers [12,13]. On the contrary, experimental data on partially ordered ferrites [6,11,14] suggest that oxygen-vacancy ordering leads to decreasing ionic conduction.…”

Section: Introductionmentioning

confidence: 99%

Oxygen ionic conduction in brownmillerite CaAl0.5Fe0.5O2.5+

Хартон

Marozau

Vyshatko

et al. 2003

Materials Research Bulletin

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The oxygen permeability of CaAl 0.5 Fe 0.5 O 2.5þd brownmillerite membranes at 1123-1273 K was found to be limited by the bulk ionic conduction, with an activation energy of 170 kJ/mol. The ion transference numbers in air are in the range 2 Â 10 À3 to 5 Â 10 À3 . The analysis of structural parameters showed that the ionic transport in the CaAl 0.5 Fe 0.5 O 2.5þd lattice is essentially along the c axis. The largest ion-migration channels are found in the perovskite-type layers formed by iron-oxygen octahedra, though diffusion in tetrahedral layers of the brownmillerite structure is also possible. Heating up to 700-800 K in air leads to losses of hyperstoichiometric oxygen, accompanied with a drastic expansion and, probably, partial disordering of the CaAl 0.5 Fe 0.5 O 2.5þd lattice. The average thermal expansion coefficients of CaAl 0.5 Fe 0.5 O 2.5þd ceramics in air are 16:7 Â 10 À6 and 12:6 Â 10 À6 K À1 at 370-850 and 930-1300 K, respectively.

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“…We used pulsed laser epitaxy to grow SCO (x = 2.5 and 3.0) thin films on (001) note that this value is much smaller compared to other bulk BM oxides, such as BaInO 2.5 (2.7 eV) or SrFeO 2.5 (2.0 eV) [16,17]. The small band gap is highly advantageous for many technological applications, e.g., for cathodes in solid oxide fuel cells, as it could realize a mixed ionic and electronic conductor at a moderate temperature.…”

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Reversal of the Lattice Structure inSrCoOxEpitaxial Thin Films Studied by Real-Time Optical Spectroscopy and First-Principles Calculations

et al. 2013

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Using real-time spectroscopic ellipsometry, we directly observed a reversible lattice and electronic structure evolution in SrCoO x (x = 2.5 − 3) epitaxial thin films. Drastically different electronic ground states, which are extremely susceptible to the oxygen content x, are found in the two topotactic phases, i.e. the brownmillerite SrCoO 2.5 and the perovskite SrCoO 3 . First principles calculations confirmed substantial differences in the electronic structure, including a metal-insulator transition, which originates from the modification in the Co valence states and crystallographic structures. More interestingly, the two phases can be reversibly controlled by changing the ambient pressure at greatly reduced temperatures. Our finding provides an important pathway to understanding the novel oxygencontent-dependent phase transition uniquely found in multivalent transition metal oxides.

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Electrical Properties of the Ferrite SrFeOy at High Temperatures

Cited by 111 publications

References 14 publications

Electrical conductivity and thermopower of (1 − x) BiFeO₃– xBi_0.5K_0.5TiO₃(x = 0.1, 0.2) ceramics near the ferroelectric to paraelectric phase transition

Electrical conductivity and thermopower of (1 − x) BiFeO₃– xBi_0.5K_0.5TiO₃(x = 0.1, 0.2) ceramics near the ferroelectric to paraelectric phase transition

Oxygen ionic conduction in brownmillerite CaAl0.5Fe0.5O2.5+

Reversal of the Lattice Structure inSrCoOxEpitaxial Thin Films Studied by Real-Time Optical Spectroscopy and First-Principles Calculations

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Electrical Properties of the Ferrite SrFeOy at High Temperatures

Cited by 111 publications

References 14 publications

Electrical conductivity and thermopower of (1 − x) BiFeO3– xBi0.5K0.5TiO3(x = 0.1, 0.2) ceramics near the ferroelectric to paraelectric phase transition

Electrical conductivity and thermopower of (1 − x) BiFeO3– xBi0.5K0.5TiO3(x = 0.1, 0.2) ceramics near the ferroelectric to paraelectric phase transition

Oxygen ionic conduction in brownmillerite CaAl0.5Fe0.5O2.5+

Reversal of the Lattice Structure inSrCoOxEpitaxial Thin Films Studied by Real-Time Optical Spectroscopy and First-Principles Calculations

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Electrical conductivity and thermopower of (1 − x) BiFeO₃– xBi_0.5K_0.5TiO₃(x = 0.1, 0.2) ceramics near the ferroelectric to paraelectric phase transition

Electrical conductivity and thermopower of (1 − x) BiFeO₃– xBi_0.5K_0.5TiO₃(x = 0.1, 0.2) ceramics near the ferroelectric to paraelectric phase transition