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Nonstoichiometry, Defect Structure and Energetics in T (La2MO4; M=Cu, Ni) and T′ (Nd2CuO4) Structures

Published online by Cambridge University Press:  26 February 2011

Anurag Dwivedi  and
A. N. Cormack
Anurag Dwivedi
Affiliation:
NYS College of Ceramics, Alfred University, Alfred, NY-14802
A. N. Cormack
Affiliation:
NYS College of Ceramics, Alfred University, Alfred, NY-14802
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Abstract

Atomistic computer simulation is performed to investigate the extent and nature of nonstoichiometry in La2CuO4, and La2NiO4. Results suggest anion Frenkel to be the dominant intrinsic defect in both compounds. Spontaneous oxidation is predicted for La2NiO4 but not for La2CuO4; however, both compounds are more easily oxidised than reduced, as opposed to Nd2CuO4, a superconducting compound with same generic formula. Oxidation takes place via accommodation of oxygen interstitials; however, the possibility of metal vacancies can not be completely ignored in La2CuO4. There is only one favorable oxygen interstitial site which is same in both the compounds La2MO4 (M=Cu, Ni). We found a favorable oxygen interstitial site in T′ structure too. Relaxed structures around an oxygen interstitial in these compounds are reported.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 209: Symposium K – Defects in Materials , 1990 , 889
Copyright
Copyright © Materials Research Society 1991

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References

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