Portland State University. Department of Physics
Date of Publication
Master of Science (M.S.) in Physics
Aluminum -- Analysis, Cobalt, Mössbauer effect
1 online resource (ii, 47 leaves, ill. 28 cm.)
Using Fe57 Mossbauer spectroscopy, two alternative sites occupied by cobalt (10-4 at. % ) impurity atoms in aluminum have been isolated. The substitutional site A is the stable position after annealing the sample above 840 K, followed by a rapid quench. The impurity atoms in site A are characterized by a single line Mossbauer spectrum (indicative of a cubic environment), a room-temperature f = 0.502 (r. m. s. displ. 0.071 A) and an I. S. (reI. to Fe) = -0.421 mm/sec. For anneals below 770 K the cobalt atoms migrate to site B, which is characterized by a well resolved quadrupole doublet (indicative of a non-cubic environment), a large change in the value of the room-temperature f = - 0.766 (r. m. s. displ. 0.071 A), I. S. = -0.150 mm/sec (increased s-electron density at the nucleus). All linewidths· are approximately 0.21 mm/sec, indicating high uniformity of impurity sites. The site distribution [A] / [B} varies from about 5 % to 95 % for anneals between 770 K and 830 K.
In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
Venkatachar, Arun, "Evidence for the existence of two stable sites for cobalt impurity atoms in aluminum" (1971). Dissertations and Theses. Paper 1477.