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Abstract: Atomistic computer simulation has been used to predict the most energetically favourable migration pathways for oxygen ion transport in tetragonal La2NiO4. Both interstitial and vacancy mechanisms have been investigated. All of the vacancy mechanisms studied exhibited lower activation energies than the interstitial process. The lowest energy process allowed migration in the a–b plane with an activation energy of 0.35 eV, migration along the c-axis was predicted to have an activation energy of 0.77 eV and interstitial migration in the a–b plane was found to have an energy barrier of 0.86 eV (in agreement with available experimental data). [Copyright &y& Elsevier]

Abstract: Using classical molecular dynamics in conjunction with an established set of Born model potentials the oxygen ion diffusion mechanism and energetics in the double perovskite PrBaCo2O5.5 were investigated in the temperature range from 650°C to 1000°C. An anisotropic oxygen diffusion mechanism with diffusion occurring predominantly in the Pr-O and Co-O layers was observed. An activation energy of E a =0.35eV was measured for the range of temperatures under study. The results are discussed in view of recent experimental and theoretical results of this and other compounds of the LnBaCo2O5+δ family. [Copyright &y& Elsevier]