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Critical exponents at the ferromagnetic transition in tetrakis(diethylamino)ethylene-C$_{60}$ (TDAE-C$_{60}$)

Ales Omerzu·Madoka Tokumoto·Bosiljka Tadic·Dragan Mihailovic
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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 $T_{c}=16.1\pm 0.05,$ we determine the susceptibility and magnetization critical exponents $γ=1.22\pm 0.02$ and $β=0.75 \pm 0.03$ respectively, and the field vs. magnetization exponent at $T_{c}$ of $δ=2.28\pm 0.14$. Hyperscaling is found to be violated by $Ω\equiv d^{\prime}-d \approx -1/4$, suggesting that the onset of ferromagnetism can be related to percolation of a particular contact configuration of C$_{60}$ molecular orientations.

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Ales Omerzu, Madoka Tokumoto, Bosiljka Tadic, Dragan Mihailovic. 2001-08-09. Critical exponents at the ferromagnetic transition in tetrakis(diethylamino)ethylene-C$_{60}$ (TDAE-C$_{60}$). https://doi.org/10.1103/physrevlett.87.177205

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