Chinese Journal of Physics[V35-No.6]

VOLUME 35, NUMBER 6, PART II

DECEMBER 1997

Magnetic and Optical Studies in K₃C₆₀
Maw-Kuen Wu¹, Patrick P. T. Leong¹, Chien-Ming Lei¹, Jjun-Hwei Hwang², and Chung-Yuan Mon² ¹ Materials Science Center and Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 300, R.O.C. ² Department of Chemistry, National Taiwan University, Taipei, Taiwan 106, R.O.C. (Received December 8, 1997)
We report the observation of new phase of bulk superconducting K₃C₆₀ with anomalous magnetic properties which suggest the presence of p-wave superconductivity. The samples are prepared by mixing stoichiometric amounts of K and C₆₀ and annealed in vacuum for a period of 5 days at 500 ^ĄCC. The magnetic susceptibility showed a temperature-hysteresis pattern which was positive at 0.2 G and negative at 2 G or above. Two distinct T_c onsets were seen at 0.2 G while three distinct T_c onsets were seen at higher magnetic fields. Photoluminescence and X-ray measurements suggested the possibility of polymerization of the C₆₀ molecules. A comparison with K₃C₆₀ samples annealed at 400^ĄCC for 5 days indicated that the annealing temperature was critical to the final product outcome.

Magnetic and Optical Studies in K₃C₆₀

Maw-Kuen Wu¹, Patrick P. T. Leong¹, Chien-Ming Lei¹, Jjun-Hwei Hwang², and Chung-Yuan Mon²

¹ Materials Science Center and Department of Physics,
National Tsing Hua University, Hsinchu, Taiwan 300, R.O.C.
² Department of Chemistry, National Taiwan University,
Taipei, Taiwan 106, R.O.C.

(Received December 8, 1997)

We report the observation of new phase of bulk superconducting K₃C₆₀ with anomalous magnetic properties which suggest the presence of p-wave superconductivity. The samples are prepared by mixing stoichiometric amounts of K and C₆₀ and annealed in vacuum for a period of 5 days at 500 ^ĄCC. The magnetic susceptibility showed a temperature-hysteresis pattern which was positive at 0.2 G and negative at 2 G or above. Two distinct T_c onsets were seen at 0.2 G while three distinct T_c onsets were seen at higher magnetic fields. Photoluminescence and X-ray measurements suggested the possibility of polymerization of the C₆₀ molecules. A comparison with K₃C₆₀ samples annealed at 400^ĄCC for 5 days indicated that the annealing temperature was critical to the final product outcome.

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