Dehydration products of gypsum - positron-annihilation and dielectric measurements

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dc.contributor.authorSerna Galán, Julio
dc.contributor.authorTroev, T.
dc.contributor.authorPetkov, M.
dc.contributor.authorAlemany, C.
dc.date.accessioned2023-06-20T18:46:59Z
dc.date.available2023-06-20T18:46:59Z
dc.date.issued1994-02-15
dc.description.abstractBassanite (CaSO_4•½ H_2O) and anhydrite (CaSO_4) are the low-temperature products of gypsum (CaSO_4·2H_2O) dehydration, which are obtained at about 373 and 433 K, respectively. These sulphates have non-centrosymmetric crystallographic point groups, but dielectric measurements do not reveal any piezo- or ferroelectric characteristic, and they practically behave like linear dielectrics. Positron lifetime spectra exhibit the existence of two different positron states, besides a free positron state. There is positronium formation in the three sulphates, and there is also evidence for the presence of a highly populated positron bound state which may be a complex state associated with positrons bound to SO_4^2- ions. Parameter S estimated from the Doppler curve and the average positron lifetime show unquestionably the sensitivity of positrons to the phase transitions gypsum-bassanite and bassanite-anhydrite.
dc.description.departmentDepto. de Óptica
dc.description.facultyFac. de Ciencias Físicas
dc.description.refereedTRUE
dc.description.statuspub
dc.eprint.idhttps://eprints.ucm.es/id/eprint/22086
dc.identifier.citation1. N. A. Lange (ed.), “Handbook of Chemistry” (McGraw-Hill, New York, 1967) p. 250. 2. “The Condensed Chemical Dictionary”, 8th Edn (Van Nostrand Reinhold, New York, 1971) p. 160. 3. L. A. Hardie, Amer. Mineralogist 52 (1967) 171. 4. P. Gay, Mineral. Mag. 35 (1965) 354. 5. Idem. ibid. 35 (1965) 347. 6. G. A. Lager, Th. Armbruster, F. J. Rotella, J. D. Jorgensen and D. G. Hinks, Amer. Mineralogist 69 (1984) 910. 7. J. D. C. McConell, D. M. Astil and P. L. Hall, Mineral. Mag. 51 (1987) 453. 8. L. Bragg (ed.), “Crystal Structures of Minerals”, Vol. IV, “The Crystalline State” (Bell, 1965) p. 139. 9. R. W. G. Wyckoff, in “Crystal Structures”, 2nd Edn, Vol. 3 (John Wiley, New York, 1965) pp. 18 and 642. 10. B. F. Pedersen, Acta Crystallogr. B38 (1982) 1074. 11. W. F. Cole and C. J. Lancucki, ibid. B30 (1974) 921. 12. M. E. Lines and A. M. Glass, in “Principles and Applications of Ferroelectrics and Related Materials” edited by W. Marshall and D. H. Wilkinson (Clarendon, Oxford, 1977) p. 608. 13. P. Kirkegaard, N. J. Pedersen and M. Eldrup, “PATFIT-88”, Risø-M-2740 (1989). 14. J. Serna, Ferroelectrics 129 (1992) 157. 15. J. Serna, unpublished work (1988–1990). 16. R. E. Green and R. E. Bell, Can. J. Phys. 35 (1957) 398. 17. K. P. Singh and R. M. Singru, Phys. Lett. 33A (1970) 463. 18. S. J. Tao, in Proceedings of 5th International Conference on Positron Annihilation, edited by R. R. Hasiguti and K. Fujiwara (Japan Institute of Metals, Aoba Aramaki, Sendai, 1979) p. 429.
dc.identifier.doi10.1007/BF00351403
dc.identifier.issn0022-2461
dc.identifier.officialurlhttp://dx.doi.org/10.1007/BF00351403
dc.identifier.relatedurlhttp://link.springer.com/
dc.identifier.urihttps://hdl.handle.net/20.500.14352/58603
dc.issue.number4
dc.journal.titleJournal of Materials Science
dc.page.final869
dc.page.initial865
dc.publisherChapman & Hall, Ltd.
dc.rights.accessRightsmetadata only access
dc.subject.cdu535
dc.subject.keywordMaterials Science
dc.subject.keywordMultidisciplinary
dc.subject.ucmÓptica (Física)
dc.subject.unesco2209.19 Óptica Física
dc.titleDehydration products of gypsum - positron-annihilation and dielectric measurements
dc.typejournal article
dc.volume.number29
dspace.entity.typePublication
relation.isAuthorOfPublication076e3bc6-0918-48a4-a920-6fe13919d721
relation.isAuthorOfPublication.latestForDiscovery076e3bc6-0918-48a4-a920-6fe13919d721
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