FERROMAGNETIC BEHAVIOR OF SUPERHIGH SURFACE-AREA CARBON

The magnetic properties of activated mesocarbon microbead (a-MCMB) were examined over the temperature range 1.7-285 K. a-MCMB has a large specific surface area of 3110 m(2) g(-1) whose surface atom ratio is 0.94. The temperature dependence of the magnetic susceptibility (chi) from 30 to 285 K is described by the Curie-Weiss equation. The (chi)-T curve shows a maximum at 4.2 +/- 0.5 K. Distinct magnetic hysteresis and residual magnetization of 0.016 emu Gg(-1) at 1.7 K is observed. Although the magnetic hysteresis loop becomes small with an increase in temperature, the hysteresis still remains even at 285 K.