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Investigation of the driving forces of metal-insulator transitions in LaSrFeNi-oxides: Correlation of crystallographic structure, electronic structure and transport

English title Investigation of the driving forces of metal-insulator transitions in LaSrFeNi-oxides: Correlation of crystallographic structure, electronic structure and transport
Applicant Braun Artur
Number 116688
Funding scheme Project funding (Div. I-III)
Research institution Labor für Hochleistungskeramik EMPA
Institution of higher education Swiss Federal Laboratories for Materials Science and Technology - EMPA
Main discipline Material Sciences
Start/End 01.08.2007 - 31.07.2010
Approved amount 130'550.00
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All Disciplines (2)

Discipline
Material Sciences
Physical Chemistry

Keywords (7)

mixed electronic/ionic conductors; strongly correlated fermion systems; metal-insulator transitions; high-temperature electrochemistry; metal insulator transitions; x-ray spectroscopy; perovskites

Lay Summary (English)

Lead
Lay summary
The electric conductivity of rare earth-transition metal ceramic materials has recently attracted much attention. Depending on delicate balance of their chemical composition, some of these materials show very peculiar effects, such as the colossal magnetoresistance, or superconductivity. These materials systems have been studied extensively at low temperatures and ambient temperatures with highly sophisticated analytical techniques in order to understand which fundamental physical mechansims make these materials behave so.

In the present project, these materials will be investigated at temperatures much higher than the Physicists usually do. At temperatures from 500 °C to 1000 °C, these materials can be used as electrodes for solid oxide fuel cells. Advanced spectroscopic characterization techniques will be applied to study changes of electric and thermal conductivity of these materials as a function of temperature and oxygen pressure.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Electronic Origin of Conductivity Changes and Isothermal Expansion of Ta- and Ti-Substituted La1/2Sr1/2Fe-Oxide in Oxidative and Reducing Atmosphere
Braun Artur, Erat Selma, Bayraktar Defne, Harvey Ashley, Graule Thomas (2012), Electronic Origin of Conductivity Changes and Isothermal Expansion of Ta- and Ti-Substituted La1/2Sr1/2Fe-Oxide in Oxidative and Reducing Atmosphere, in Chem. Mater., 24(8), 1529-1535.
X-ray absorption investigation of the valence state and electronic structure of La1-xCaxCoO3-delta in comparison with La1-xSrxCoO3-delta and La1-xSrxFeO3-delta
Haas O, Ludwig C, Bergmann U, Singh RN, Braun A, Graule T (2011), X-ray absorption investigation of the valence state and electronic structure of La1-xCaxCoO3-delta in comparison with La1-xSrxCoO3-delta and La1-xSrxFeO3-delta, in JOURNAL OF SOLID STATE CHEMISTRY, 184(12), 3163-3171.
High temperature oxygen near edge x-ray absorption fine structure valence band spectra and conductivity of LaFe3/4Ni1/4O3 from 300 to 773K
Braun A, Erat S, Ariffin AK, Manzke R, Wadati H, Graule T, Gauckler LJ (2011), High temperature oxygen near edge x-ray absorption fine structure valence band spectra and conductivity of LaFe3/4Ni1/4O3 from 300 to 773K, in APPLIED PHYSICS LETTERS, 99(20), 2112-1-2112-3.
Evolution of an Oxygen Near-Edge X-ray Absorption Fine Structure Transition in the Upper Hubbard Band in alpha-Fe2O3 upon Electrochemical Oxidation
Bora DK, Braun A, Erat S, Ariffin AK, Lohnert R, Sivula K, Topfer J, Gratzel M, Manzke R, Graule T, Constable EC (2011), Evolution of an Oxygen Near-Edge X-ray Absorption Fine Structure Transition in the Upper Hubbard Band in alpha-Fe2O3 upon Electrochemical Oxidation, in JOURNAL OF PHYSICAL CHEMISTRY C, 115(13), 5619-5625.
Entanglement of charge transfer, hole doping, exchange interaction, and octahedron tilting angle and their influence on the conductivity of La1-xSrxFe0.75Ni0.25O3-delta: A combination of x-ray spectroscopy and diffraction
Erat S, Braun A, Piamonteze C, Liu Z, Ovalle A, Schindler H, Graule T, Gauckler LJ (2010), Entanglement of charge transfer, hole doping, exchange interaction, and octahedron tilting angle and their influence on the conductivity of La1-xSrxFe0.75Ni0.25O3-delta: A combination of x-ray spectroscopy and diffraction, in JOURNAL OF APPLIED PHYSICS, 108(12), 4906-1-4906-3.
Iron-resonant valence band photoemission and oxygen near edge x-ray absorption fine structure study on La1-xSrxFe0.75Ni0.25O3-delta
Erat S, Wadati H, Aksoy F, Liu Z, Graule T, Gauckler LJ, Braun A (2010), Iron-resonant valence band photoemission and oxygen near edge x-ray absorption fine structure study on La1-xSrxFe0.75Ni0.25O3-delta, in APPLIED PHYSICS LETTERS, 97(12), 4101-1-4101-3.
Correlation of conductivity and angle integrated valence band photoemission characteristics in single crystal iron perovskites for 300 K < T < 800 K: Comparison of surface and bulk sensitive methods
Braun A, Mun BS, Sun Y, Liu Z, Groning O, Mader R, Erat S, Zhang X, Mao SS, Pomjakushina E, Conder K, Graule T (2010), Correlation of conductivity and angle integrated valence band photoemission characteristics in single crystal iron perovskites for 300 K < T < 800 K: Comparison of surface and bulk sensitive methods, in JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA, 181(1), 56-62.
Correlation of O (1s) and Fe (2p) near edge x-ray absorption fine structure spectra and electrical conductivity of La1-xSrxFe0.75Ni0.25O3-delta
Erat S, Braun A, Ovalle A, Piamonteze C, Liu Z, Graule T, Gauckler LJ (2009), Correlation of O (1s) and Fe (2p) near edge x-ray absorption fine structure spectra and electrical conductivity of La1-xSrxFe0.75Ni0.25O3-delta, in APPLIED PHYSICS LETTERS, 95(17), 4108-1-4108-3.
Correlation of high temperature x-ray photoemission valence band spectra and conductivity in strained LaSrFeNi oxide on SrTiO3(110)
Braun A, Zhang X, Sun Y, Muller U, Liu Z, Erat S, Ari M, Grimmer H, Mao SS, Graule T (2009), Correlation of high temperature x-ray photoemission valence band spectra and conductivity in strained LaSrFeNi oxide on SrTiO3(110), in APPLIED PHYSICS LETTERS, 95(2), 1-3.
Pre-edges in oxygen (1s) x-ray absorption spectra: A spectral indicator for electron hole depletion and transport blocking in iron perovskites
Braun A, Bayraktar D, Erat S, Harvey AS, Beckel D, Purton JA, Holtappels P, Gauckler LJ, Graule T (2009), Pre-edges in oxygen (1s) x-ray absorption spectra: A spectral indicator for electron hole depletion and transport blocking in iron perovskites, in APPLIED PHYSICS LETTERS, 94(20), 2102-1-2102-3.
Electron hole-phonon interaction, correlation of structure, and conductivity in single crystal La0.9Sr0.1FeO3-delta
Braun A, Richter J, Harvey AS, Erat S, Infortuna A, Frei A, Pomjakushina E, Mun BS, Holtappels P, Vogt U, Conder K, Gauckler LJ, Graule T (2008), Electron hole-phonon interaction, correlation of structure, and conductivity in single crystal La0.9Sr0.1FeO3-delta, in APPLIED PHYSICS LETTERS, 93(26), 2103-1-2103-3.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
NIMS, Conference Energy & Environment 12.07.2010 Tsukuba, Japan


Self-organised

Title Date Place
ALS User's Meetings 15.10.2009 Berkeley, CA, United States

Associated projects

Number Title Start Funding scheme
121306 Fundamental Aspects of Photocatalysis and Photoelectrochemistry / Basic Research Instrumentation for Functional Characterization 01.07.2008 R'EQUIP
147413 International Exploratory Workshop on Soft X-rays, Electrochemistry, and Energy Materials 01.05.2013 International Exploratory Workshops

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