Low-temperature magnetization of FeCl3 intercalated graphite

We report magnetization measurements on ferric chloride intercalated graphi te in the temperature range 1 K < T < 4 K for stages of index n = 1-6 and 8 . All stages exhibit a sharp increase in M(T) at T = 1.7 K as the temperatu re decreases and a subsequent saturation below 1.4 K. The saturation magnet ization, when normalized to the iron contents, exhibits a strong stage depe ndence(M(1 K) similar to e(n)), up to stage 5 and then deviates for higher stages. For the stage 6 sample M(1 K) has a linear dependence on the trappe d applied field (H < 0.5 G) and long relaxation times ranging from under on e to more than 4 min. The relaxation time T(T) has a lambda shape with a pe ak temperature of 1.45 K, with similar results for stage 3. (C) 2000 Elsevi er Science B.V. All rights reserved.