Critical exponents at the ferromagnetic transition in tetrakis(dimethylamino)ethylene-C(60) (TDAE- C(60)).

Abstract

Critical exponents at the ferromagnetic transition were measured for the first time in an organic ferromagnetic material tetrakis(dimethylamino)ethylene fullerene[60] (TDAE- C(60)). From a complete magnetization-temperature-field data set near T(c) = 16.1+/-0.05, we determine the susceptibility and magnetization critical exponents gamma = 1.22+/-0.02 and beta = 0.75+/-0.03, respectively, and the field vs magnetization exponent at T(c) of delta = 2.28+/-0.14. Hyperscaling is found to be violated by Omega identical with d(')-d approximately -1/4, suggesting that the onset of ferromagnetism can be related to percolation of a particular contact configuration of C(60) molecular orientations.