Revealing of the re-entrant spin-glass phase in TDAE-C 60 with linear and non-linear AC susceptibility measurements

Abstract

We report on the discovery of a re-entrant spin glass phase in α-TDAE-C 60 . Apart from a behaviour associated with the ferromagnetic transition at 16K, the linear AC susceptibility of α-TDAE-C 60 shows a small decrease below 10 K in the real part and an additional broad peak at T RSG = 7 K in the imaginary part, which is also frequency dependent. In addition, among higher harmonics of the AC response, which correspond to the non-linear susceptibility, only the odd harmonics show a peak at T RSG - contrary to the ferromagnetic transition at T c = 16 K where both the odd and even harmonics show a divergence.