Role of minority light holes in the Hall effect of pregraphitic carbons

Results on the temperature and magnetic field dependence of the Hall effect in pregraphitic pyrocarbons heat treated between 1700 degrees C and 2200 degrees C are presented. The experimental data are discussed in terms of the two-carrier-minority and majority holes-model. It is shown that this model is able to reproduce all the set of experimental data in the low temperature range. Best fit calculations clearly show that minority carriers play a significant role, especially at low temperature. The temperature dependence of the low field Hall coefficient: R/sub H0/ originates from that of the minority holes mobility, while the field dependence of R/sub H/ is due to the high mobility of those carriers. Hall effect measurements appear to be well suited for investigating properties of high mobility minority carriers in disordered graphite.Anglai