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Defect processes in orthorhombic LnBaCo2O5.5 double perovskites
I D Seymour1, A Chroneos, J A Kilner
1Department of Materials, Imperial College London, London SW7 2AZ, United Kingdom.
Physical Chemistry Chemical Physics : PCCP
|July 20, 2011
Summary
Static atomistic simulations reveal that Ln/Ba antisite disorder is the lowest energy defect in LnBaCo(2)O(5.5) perovskites. Oxygen Frenkel disorder decreases with increasing Ln cation size, with PrBaCo(2)O(5.5) showing optimal defect balance.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Computational Materials Science
Background:
- Orthorhombic LnBaCo(2)O(5.5) double perovskites are promising for various applications.
- Understanding intrinsic defect processes is crucial for optimizing their properties.
Purpose of the Study:
- To investigate intrinsic defect formation energies in a series of LnBaCo(2)O(5.5) materials.
- To determine the dominant defect mechanisms and their dependence on the Ln cation.
Main Methods:
- Static atomistic simulations utilizing the Born model.
- Calculations focused on antisite disorder and oxygen Frenkel disorder.
Main Results:
- Ln/Ba antisite disorder was identified as the lowest energy intrinsic defect.
- Oxygen Frenkel disorder energy decreases with increasing size of the Ln cation.
- Oxygen vacancies tend to cluster with Ba antisite defects.
Conclusions:
- The interplay between antisite and oxygen Frenkel energies influences oxygen vacancy transport.
- PrBaCo(2)O(5.5) exhibits a favorable balance of low oxygen Frenkel energy and high antisite energy, promoting lattice order.
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