Defect characterization of slow-cooled and quenched samples of calcium-copper-titanate through positron annihilation spectroscopy. Issue 10 (26th November 2019)

• Record Type: Journal Article
• Authors: Meshiya, U. M.; Jani, K. K.; Mange, P. L.; Barad, D. V.; Raval, P. Y.; Modi, K. B.; Nambissan, P. M. G.
• Is Part Of: Spectroscopy letters. Volume 52:Issue 10(2019)
• Page Start: 633
• Page End: 641
• Publication Date: 2019-11-26
• Subjects: Calcium-copper-titanate -- defects -- positron annihilation -- quenching -- vacancies; Spectrum analysis -- Periodicals; 543.5
• DOI: 10.1080/00387010.2019.1681462
• Languages: English
• ISSNs: 0038-7010

Abstract

Abstract: Positron annihilation lifetime and Doppler-broadened gamma-ray spectra have been analyzed for slow-cooled and thermally quenched polycrystalline samples of calcium-copper-titanate. Two positron lifetimes revealing the characteristic defects in the respective samples were carefully analyzed to compare and contrast the significance of their origin and implication. A third component arising from positronium formation at the powdered particle surfaces has been considered in the analysis although its significance is lost in its very small intensity (∼ 1.1–1.2%). In the quenched sample, the defect-specific long positron lifetime (τ2 ) is found to larger and the mean lifetime smaller while its intensity I 2 is found drastically smaller and the concentration of defects less by an order of magnitude as compared to the slow-cooled sample. The observed changes in electrical parameters of slow-cooled and quenched samples were found to have correlations with the positron annihilation lifetime and Doppler-broadened lineshape parameters.