The pressure dependence of the superconducting transition temperature Tc of the primitive cubic quaternary fulleride Na2Rb0.5Cs0.5C60 (Tc=8.4K at ambient pressure) is studied by the ac susceptibility technique to 2.5 kbar. The observed value of dTc/dP is -1.22(2) K/kbar. Using the compressibility data available for Na2CsC60, we find that the evolution of Tc with interfullerene spacing in Na2Rb0.5Cs0.5C60 mimics that observed for Na2CsC60 and is comparable to the fee fulleride K3C60. However, the rate of change, dTc/da, is about 5-6 times smaller than that reported for the quaternary fullerides Na2Rb1-xCsxC60 as a function of x at ambient pressure, implying the presence of a strong alkali-metal specific effect, responsible for the differing effects of chemical and physical pressure on the superconducting properties of Pa3̄ fullerides.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 1999|
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