May 26 – 29, 2015
Hotel Rigi Kulm
Europe/Zurich timezone
7th Status Meeting 2015, Rigi Kulm

Temperature dependent oxygen disorder in Pr(2-x)Sr(x) NiO(4+δ) by high-resolution single crystal neutron diffraction on HEIDI@MLZ

May 27, 2015, 8:45 AM
30m
Main Lecture Hall (Hotel Rigi Kulm)

Main Lecture Hall

Hotel Rigi Kulm

6410 Rigi Kulm Switzerland

Speaker

Mr Sumit Ranjan Maity (Technical university of Munich)

Description

Mixed-ionic electronic conductors (MIEC) offer significant advantages over conventional cathodes especially in the intermediate temperature range for solid oxide fuel cell applications. In this context, Ruddlesden-Popper type layered oxides have taken much attention. Among them Pr2 NiO(4+δ) is a promising candidate as it offers high electronic conductivity similar to those conventional cathode materials but in addition shows a very high oxygen diffusion coefficient even at room temperature. Behind these remarkable physical properties the oxygen atoms and their disorder between interstitial and apical sites play a key role in low-moderate temperature region, allowing phonon assisted diffusion in the moderate temperature region. In a similar way to high temperature superconductors, Sr doping or hole doping may increase the electronic conductivity but significantly lowers the delocalization of oxygen atoms. Nevertheless, it offers to make a direct comparison of oxygen diffusion mechanism with the undoped sample. For these reasons, our present work focuses to analyze apical oxygen disorder in Pr(1.5)Sr(0.5)NiO(4+δ) by single crystal neutron diffraction on HEIDI@MLZ as a function of temperature. Neutrons are point scatterer and thus a perfect tool to explore disordered structures. We will discuss the displacement amplitudes of the apical oxygen atoms as a function of Sr-doping and temperature, analyzed by classical Fourier techniques and by Maximum Entropy algorithm, in order to conclude and separate possible static and dynamic contributions

Primary author

Mr Sumit Ranjan Maity (Technical university of Munich)

Co-authors

Prof. Werner PAULUS (UNIVERSITE DE MONTPELLIER 2, France) Prof. Winfried PETRY (Technical University MÜNCHEN, Germany)

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