화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.271, 51-56, 1995
Ferromagnetic Interaction in C-60 Charge-Transfer Complexes
C-60[TDAE] was the first and so far the only C-60 CT complex which exhibits molecular ferromagnetism with a Curie temperature of about 16 K [1]. Despite extensively investigated a convincing access to the origin of the low temperature phase of this C-60 CT complex is still missing. The 3 fold degeneracy of the C-60 HOMO is lifted by a change of the C-60 conformation, and we find a transition from a static low temperature Jahn-Teller distortion to a dynamic one at about 140 K. The excess electron is concentrated in a belt around the equator of the C-60(-) The distorted C-60 molecules have a spin density distribution with an axial symmetry and are aligned along the crystallographic axes. This orientational ordering of the C-60(-) molecules is the necessary precursor to a ferromagnetic spin glass type ordering in C-60[TDAE] which was interpreted in terms of spin polarisation between C-60(-.) and TDAE(+.) by Yamaguchi et al [2].