First Advisor

Donald G. Howard

Term of Graduation

Summer 1971

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Physics






Aluminum -- Analysis, Cobalt, Mössbauer effect



Physical Description

1 online resource (ii, 47 pages)


Using Fe57Mössbauer 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 Mössbauer 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.


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