A Search for Thermal Vacancies Forming Close Frenkel Pairs in Fe--Cr Alloys
J. Chojcan
Institute of Experimental Physics, University of Wroc³aw, Pl. M. Borna 9, 50-204 Wroc³aw, Poland
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The room temperature Mössbauer spectra of 57Fe were measured for the bcc Fe0.948Cr0.052 solid solution quenched into water being at about 295 K from different temperatures not exceeding 1000 K, i.e. from the temperatures for which probabilities of formation of "clear" (Schottky) vacancies as well as vacancies forming the separate interstitial--vacancy (Frenkel) pairs are negligibly low. The obtained data were analysed in terms of concentration of unoccupied places in the 14-site surroundings of an 57Fe Mössbauer probe in the sample. It turned out that the concentration of vacancies detected by the probe increases with temperature very rapidly -- at the rate of about 10-4 K-1. The result may suggest that the Mössbauer probe is sensitive to a possible thermal distortion of the lattice or creation of very close Frenkel pairs (the interstitial is the nearest neighbour of the vacant lattice site).
DOI: 10.12693/APhysPolA.100.723
PACS numbers: 61.72.Ji, 76.80.+y