Accession Number : AD0426185


Title :   RESEARCH AND DEVELOPMENT ON ADVANCED GRAPHITE MATERIALS, VOLUME XX. THE ELECTRIC AND MAGNETIC PROPERTIES OF PYROLYTIC GRAPHITE


Corporate Author : NATIONAL CARBON CO INC CLEVELAND OH


Personal Author(s) : Wagoner, G ; Eckstein, B H


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/426185.pdf


Report Date : Nov 1963


Pagination or Media Count : 29


Abstract : This paper concerns the electric and magnetic properties of a series of highly turbostratic pyrolytic graphic deposits. The diamagnetic susceptibility, Hall coefficient, and electron spin resonance g value are observed to have much larger magnitudes than corresponding measurements made on single crystals of graphite. The results are interpreted as being due to the turbostratic character of the deposit which brings about a decreased interaction between the randomly rotated graphitic planes. The overlap of the electron and hole bands is thereby reduced and as a first approximation one can interpret the results using the simple two dimensional model of Wallace. McClure's diamagnetism formula, which is based on the Wallace model, yields a maximum trace value of -39 emu/g. The largest observed value is -33.5 emu/g, a diamagnetism almost 50% greater than the normal single crystal value of -22.8 emu/g.


Descriptors :   *PYROLYTIC GRAPHITE , MAGNETIC PROPERTIES , CRYSTAL STRUCTURE , PREPARATION , PHYSICAL PROPERTIES , HIGH TEMPERATURE , HALL EFFECT , THEORY , METALLOGRAPHY , ELECTRICAL PROPERTIES , ELECTRONS , MATHEMATICAL ANALYSIS , VACUUM APPARATUS , SPINNING(MOTION) , INTEGRAL EQUATIONS


Subject Categories : Ceramics, Refractories and Glass


Distribution Statement : APPROVED FOR PUBLIC RELEASE