Precise Pressure Dependence of the Superconducting Transition Temperature of FeSe: Resistivity and 77Se-NMR Study
Precise Pressure Dependence of the Superconducting Transition Temperature of FeSe: Resistivity and 77Se-NMR Study
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DOI：
10.1143/jpsj.78.063704
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发表时间：
2009-06-01
影响因子：
1.7
通讯作者：
Takano, Yoshihiko
中科院分区：
文献类型：
--
作者：
Masaki, Satoru;Kotegawa, Hisashi;Takano, Yoshihiko
我们报告精确的压力依赖性FeSe从电阻率测量高达4.15 GPa。超导转变温度（Tc）随压力的增加而敏感地增加，但在0.5 - 1.5GPa之间有一个平台。由零电阻确定的最大Tc在约3.5 GPa时为21 K。在4.15GPa时，起始温度达到37K左右。我们还用Se-77-NMR测量了压力下的核自旋-晶格弛豫速率1/T~（-1）。1/T-1表明在零电阻态实现了体超导。1/T1T的压力依赖性在Tc之上显示出一个平台，以及T-c的压力依赖性，这清楚地证明了1/T1T和T-c之间的密切关系。自旋涨落被认为是超导电性机制的一部分。
We report the precise pressure dependence of FeSe from a resistivity measurement up to 4.15 GPa. Superconducting transition temperature (T-c) increases sensitively under pressure, but shows a plateau between 0.5-1.5GPa. The maximum T-c, which is determined by zero resistance, is 21 K at approximately 3.5 GPa. The onset value reaches similar to 37 K at 4.15 GPa. We also measure the nuclear spin-lattice relaxation rate 1/T-1 under pressure using Se-77-NMR measurement. 1/T-1 shows that bulk superconductivity is realized in the zero-resistance state. The pressure dependence of 1/T1T just above Tc shows a plateau as well as the pressure dependence of T-c, which gives clear evidence of the close relationship between 1/T1T and T-c. Spin fluctuations are suggested to contribute to the mechanism of superconductivity.