Vacancy formation volume in indium from positron-annihilation measurements

Abstract

An equilibrium method for the determination of the vacancy formation volume in many metals is provided by the trapping of positrons at vacancies. Utilizing a Bridgman press and angular-correlation counting techniques, the vacancy formation volume in metallic indium has been determined to be 6.1 + 0,2 cm'/mole, or 39+ 1% of the molar volume.

Defects in Metals

“…These techniques have been applied successfully to a variety of materials: pure metals (Seeger, 1973;Siegel, 1978;West, 1979;Siegel, 1982;Schaefer, 1982;Hautojärvi, 1987;Schaefer, 1987), intermetallic compounds (Schaefer et al, 1999;Sprengel et al, 2002), and semiconductors and ceramics (Rempel et al, 2002). Since PAS experiments under extreme conditions are not too difficult, they have served to determine the formation volume of vacancies, in which the effect of pressure on the vacancy concentration is to be measured (Dickman et al, 1977;Wolff et al, 1997;Müller et al, 2001). Migration of vacancies can also be studied by PAS, through the kinetics of equilibration on abrupt changes in temperature similar to Figure 29 (Schaefer and Schmid, 1989;Würschum et al, 1995).…”

Investigation of Thermal Equilibrium Vacancies in Metals by Positron Annihilation

“…***) derived by using (7) [58] 0.66 0.04 (AC) [58] 0.5 +_ 0.03 (AC) [58] 0.54 k 0.02 (AC) [58] 0.52 k 0.02 (DB) [64] 0.54 k 0.03 (DB) [66] 0.46**) (f) 1. 28 +_ 0.07 (T) (7) 0.9 +_ 0.1 (7) 1.60 0.15 (DB) [42] 1.53 +_ 0.15 (DB) [42] 1.54 k 0.15 (DB) [42] 1.78 f 0.1 (DB) [3] 1.32 f 0.04 (DB) [3] 1. 34 lifetime studies the reader is referred to earlier reviews 13, 21 to 251 as well as to the data listed in Table 1.…”

“…3) an apparent value HT17 = (1. 28 A realistic interpretation of the temperature variation of tl in Cu may be given by thermally activated detrapping of positrons from thermal equilibrium vacancies 1391. From the Arrhenius plot of aCt (see Fig.…”

Direct measurement of vacancy relaxation by dilatometry

“…1 One way is via the pressure dependence of thermal vacancy formation which can be measured by positron annihilation. 2,3 Another approach, the pressure dependence of self-diffusion yields the sum of vacancy formation and migration volumes. 4 A powerful tool for measuring the volume associated with lattice vacancies is dilatometry.…”