We have studied crystal structure, magnetism, and electric transport properties of a europium fulleride Eu6C60 and its Sr-substituted compounds, Eu6-xSrxC60. They have a bcc structure, which is an isostructure of other M6C60 (M represents an alkali atom or an alkaline-earth atom). Magnetic measurements revealed that magnetic moment is ascribed to the divalent europium atom with S=7/2 spin, and a ferromagnetic transition was observed at TC=10-14 K. In EU6C60, we also confirm the ferromagnetic transition by heat-capacity measurement. The striking feature in Eu6-xSrxC60 is very large negative magnetoresistance at low temperature; the resistivity ratio p(H=9 T)/p(H=0 T) reaches almost 10-3 at Eu6C60. Such large magnetoresistance is the manifestation of a strong π-f interaction between conduction carriers on C60 and 4f electrons of Eu.
|Number of pages||6|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Apr 1 2002|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics