Spontaneous Magnetic Ordering in the Fullerene Charge-Transfer Salt (TDAE)C ₆₀

Abstract

The zero-field muon spin relaxation technique has been used in the direct observation of spontaneous magnetic order below a Curie temperature (T(c)) of approximately 16.1 kelvin in the fullerene charge-transfer salt (tetrakisdimethylaminoethylene)C(60) [(TDAE)C(60)]. Coherent ordering of the electronic magnetic moments leads to a local field of 68(1) gauss at the muon site at 3.2 kelvin (parentheses indicate the error in the last digit). Substantial spatially inhomogeneous effects are manifested in the distribution of the local fields, whose width amounts to 48(2) gauss at the same temperature. The temperature evolution of the internal magnetic field below the freezing temperature mirrors that of the saturation magnetization, closely following the behavior expected for collective spin wave (magnon) excitations. The transition to a ferromagnetic state with a T(c) higher than that of any other organic material is now authenticated.

Fullerene‐induced magnetization training effect in single molecular magnet

“…We suppose that the formation of Mn 12 :C 60 complexes leads to the orientational control of magnetism, as fullerenes are known to have a coupling between spin and molecular orientational order/disorder: since the overlapping of molecular orbitals define the intermolecular exchange interaction and the orbitals are attached to molecular frames, space ordering of the molecules will result in ordering of spins. Similar mechanism has been observed for other fullerene-containing molecular solids [9][10][11]. As shown by the authors of Ref.…”

Solid State and Magnetic Properties of Pure, Intercalated and Superconducting Fullerenes

“…Spin glass features were seen in AC susceptibility [101], capacity [102], electron spin resonance (ESR) [103] and muon rotation (µSR) [104] measurements. More recently, long range order was inferred from the rather narrow local magnetic field distribution probed by implanted muons [105,106], and from single crystal ESR [107]. The strongly anisotropic ESR line intensity was interpreted in terms of an antiferromagnetic exchange along the c axis, leading to weak ferromagnetism of the Dzyaloshinsky-Moria type [108,109].…”

Muon studies of organic ferromagnets and conductors

“…1), it is possible to make a charge transfer salt with C60 [16]. The resulting material, TDAE-C60, is electrically conducting and shows a ferromagneticlike transition at 16.1 K. However it is not metallic [17] anda ~tSR experiment [18] shows a broad distribution of internal fields at the muon site which could be consistent with incommensurate magnetic order resulting from density-wave formation.…”