A scaling approach to the transverse magnetoresistance of kish graphite at 77 K

A scaling of magnetoresistance Delta rho/rho(0) was examined using B/rho(0) at liquid nitrogen temperature for kish graphite (KG) specimens with different values of residual resistivity ratio RRR between 3.92 and 35.6. The plots of Delta rho/rho(0) against B/rho(0) and the exponent n against B/rho(0) in Delta rho/rho(0) proportional to B-n varied systematically with RRR. The exponent n against B/rho(0) plots showed a minimum and maximum of n. The values of the minimum and maximum decrease with decreasing RRR, and the values of B/rho(0) at the minimum and the maximum approach each other with the decrease of RRR. The minimum and maximum seem to coincide for the specimen with lower RRR than 3.92. The saturation of n around n=1 is found in the high B/rho(0) region only for the specimens with RRR < 8. (C) 1997 Elsevier Science Ltd.