Magnetic properties of carbon nanoparticles

Abstract

Abstract. Magnetization M (T, B) of powder and glassy samples containing carbon nanoparticles is investigated in the interval of temperatures T between ~ 3  300 K and magnetic fields B up to 5 T. Low-field magnetization, M (T), exhibits a strong magnetic irreversibility, which is suppressed above the field of ~ 1 T. The dependence of M (B) saturates at high temperatures above B ~ 2 T, magnetic hysteresis is observed already at 300 K. The values of the saturation magnetization, the coercivity field and the maximum blocking temperature are obtained. Analysis of the experimental data gives evidence for concentration of the magnetization close to the surface of the particles, which is consistent with the origin of magnetism in nanocarbon presumably due to intrinsic disorder and surface defects.

The Structure and ferromagnetism of carbon nanofibers from polyacrylonitrile/ polyvinylpyrrolidone

“…Several reports have been published describing magnetism observed in carbon systems. The magnetic moments produced in carbon materials are suspected to be due to the existence of defects [6,20]. For example, hydrogen passivated zigzag and armchair edges [21]; carbon dangling bonds or vacancyinterstitial complexes [3,19], adatom defects [22][23] and hydrogen adsorption defects [24] were predicted to induce local magnetic moments and magnetic order in graphite or graphene [12].…”

Structure and Ferromagnetism in Carbon Nanofibers from PAN/PVP

“…Several reports have been published describing magnetism observed in carbon systems. The magnetic moments produced in carbon materials are suspected to be due to the existence of defects [5,22]. For example, hydrogen passivated zigzag and armchair edges [23]; carbon dangling bonds or vacancy-interstitial complexes [3] [21], adatom defects [24,25] and hydrogen adsorption defects [26] were predicted to induce local magnetic moments and magnetic order in graphite or graphene [15].…”