Details

Autor(en) / Beteiligte

• BANDYOPADHYAY, S
• ROY, A
• DAS, D
• GHUGRE, S. S
• GHOSE, J

Titel

Investigation of nanocrystalline CoFe2O4 by positron annihilation lifetime spectroscopy

Ist Teil von

• Philosophical magazine (Abingdon, England), 2003-02, Vol.83 (6), p.765-773

Ort / Verlag

Abingdon: Taylor and Francis

Erscheinungsjahr

2003

Quelle

Taylor & Francis Journals Auto-Holdings Collection

Beschreibungen/Notizen

• Nanoparticles of cobalt ferrite prepared by the co-precipitation method with crystallite size varying from 4.7 to 41 nm have been characterized by positron annihilation lifetime spectroscopy. Three lifetime components are fitted to the lifetime data. The shortest lifetime component is attributed to the delocalized positron lifetime shortened by defect trapping. The intermediate lifetime is assigned to the positron annihilation in diffuse vacancy clusters or microvoids at the grain boundaries and at the grain-boundary triple points. The longest component corresponds to the pick-oft' annihilation of orthopositronium formed at the larger voids. The variations in these lifetimes and their relative intensities with annealing temperature and crystallite size have been studied in detail.