Open AccessImperfections in the structure of cobalt. I. Experimental work and proposed structure
Author(s) -
Olive S. Edwards,
H. Lipson
Publication year - 1942
Publication title -
proceedings of the royal society of london. series a, mathematical and physical sciences
Language(s) - English
Resource type - Journals
eISSN - 2053-9169
pISSN - 0080-4630
DOI - 10.1098/rspa.1942.0039
Subject(s) - cobalt , hexagonal crystal system , work (physics) , oscillation (cell signaling) , zero (linguistics) , crystallography , condensed matter physics , materials science , geometry , physics , chemistry , mathematics , quantum mechanics , metallurgy , biochemistry , linguistics , philosophy
X-ray powder photographs of hexagonal cobalt have a remarkable mixture of sharp and diffuse lines. The sharp lines are those with 1/3 (h - k ) integral and those withl zero; all others are more or less diffuse. An explanation of this is produced, based on the possibility of faults occurring in the structure because there are two different ways in which one close-packed layer of atoms can be put on to another. It is shown theoretically that if such faults are repeated at regular intervals the reflexions with 1/3 (h - k ) integral are not affected, but the positions and intensities of the other lines are modified although they remain sharp. These results suggest that a structure with random faults would give broadened reflexions, but the broadening is such that it would not show for lines withl zero on powder photographs. Evidence from oscillation photographs and from measurement of a powder photograph is adduced in support of this theory.