Magnetism of pure, disordered carbon films prepared by pulsed laser deposition

We have studied the magnetization of disordered, pure carbon films in order to search for signs of para-, ferro-or antiferromagnetism. Carbon films on silicon substrates were produced by pulsed laser deposition in high vacuum and at room temperature using pressed ultra-clean graphite powder as target. The magnetization shows a Curie-Weiss behaviour added to a temperature-independent term. Annealing the films at 1000 degrees C and in high-vacuum eliminates completely the Curie-Weiss contribution. We compare our results with those recently obtained in activated carbon fibers. (C) 2004 Elsevier B.V. All rights reserved.