Structural, electrochemical and magnetic characterization of the layered-type PrBa0.5Sr0.5Co2O5+δ perovskite
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Structural, electrical and magnetic properties of the layered cobaltite PrBa0.5Sr0.5Co2O5+δ have been investigated by means of neutron diffraction, electron diffraction, thermogravimetric analysis and SQUID magnetometry. Rietveld analysis of neutron diffraction data shows the ordered distribution of oxygen vacancies in [PrOδ] planes which doubles the lattice parameters from the simple perovskite cell parameter as a≈2ap and c≈2ap (ap is the cell parameter of the simple Perovskite) yielding tetragonal symmetry in the P4/mmm space group. On heating, above 573 K in air, structural rearrangement takes place and the structure can be defined as a≈ap and c≈2ap in the same space group. Oxygen occupancies have been determined as a function of temperature from neutron diffraction results. Initially (≥373 K), oxygen occupancy was increased and then decreased with increasing temperature. It was found that at 973 K the total oxygen loss is calculated about 0.265 oxygen/formula unit. Oxygen vacancy ordering was observed below 573 K, and the oxygen occupancy decreases as cell volume increases with increasing temperature. Area specific resistance (ASR) measurements show a resistance of 0.153 Ωcm2 and 0.286 Ωcm2 at 973 K and 923 K, respectively. On cooling, paramagnetic to ferromagnetic and an incomplete ferromagnetic to antiferromagnetic transition takes place. Different behaviours in field cooled and zero-field-cooled measurements leads to a coexistence of ferromagnetic and antiferromagnetic order.
Azad , A K , Irvine , J T S & Kim , J 2014 , ' Structural, electrochemical and magnetic characterization of the layered-type PrBa0.5Sr0.5Co2O5+δ perovskite ' Journal of Solid State Chemistry , vol 213 , pp. 268-274 . DOI: 10.1016/j.jssc.2014.03.008
Journal of Solid State Chemistry
Copyright 2014, Elsevier. This is the accepted version manuscript of an article published in the Journal of Solid State Chemistry. The final version of record is available at http://www.sciencedirect.com/science/article/pii/S0022459614001042Copyright 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/)
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