Investigation of the Electric and Magnetic Properties of Intercalated Graphites.
Final rept. 30 Sep 82-29 Sep 86,
BOSTON UNIV MA DEPT OF PHYSICS
Pagination or Media Count:
The picture which emerges from our investigations is that we are indeed observing the behavior of a two dimensional magnetic system. The low dimensionality is brought about by the shielding of the intercalant layers by the intervening graphite layers. The shielding also depends on the charge transfer between the intercalant and the graphics. In graphite there is a band near K O about half filled with electrons 10. The intercalation of an acceptor compound will draw off those electrons so that the electrical conduction is hole like. Thus low stages exhibit a positive Hall coefficient. The shielding of the intercalant layers is due to electromagnetic shielding analogous to the skin effect, where the skin depth is a function of the electrical conductivity, which in turn is a function of the number of charge carriers. Stages 1 to 5 almost empty the band of electrons and thus the graphite layers have maximum conductivity. Above stage 5, the quantity of acceptors is not large enough to absorb all the electrons which can be donated by the graphite, and the conductivity of the graphite layers decreases. Moreover, the conductivity, according to our Hall measurements, is due to both positive and negative carriers.
- Laminates and Composite Materials