Specific he at and critical field s of the organic superconductor β"-(BEDT-TTF )2SF5CH2CF2SO3
Specific he at and critical field s of the organic superconductor β"-(BEDT-TTF )2SF5CH2CF2SO3
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有机超导体β"-(BEDT-TTF)2SF5CH2CF2SO3的比热和临界场
DOI：
10.1103/physrevb.57.3084
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发表时间：
1998
影响因子：
8.6
通讯作者：
D. Beckmanm
中科院分区：
文献类型：
--
作者：
S. Wanka;J. Hagel;D. Beckmanm
我们报道了${\ensuremath{\beta}}^{\ensuremath{''}}\ensuremath{-}(\mathrm{BEDT}\ensuremath{-}\mathrm{TTF}{)}_{2}{\mathrm{SF}}_{5}{\mathrm{CH}}_{2}{\mathrm{CF}}_{2}{\mathrm{SO}}_{3}$的比热、磁化和交流磁化率测量，是一种有机超导体，其K为${T}_{c}=4.5$，其中BEDT-TTF代表双（乙二硫代）-四硫代戊烯。在超导$(B=0$ T)和正常$(B=3.5$ T)状态下，比热$C$在${T}_{c}$处的跃变和$C$比热差的确切形式可以用强耦合的BCS理论很好地描述。我们估计一个电子-声子耦合参数$\ensuremath{\lambda}\ensuremath{\approx}1.1$。从$C$在磁场中的测量中，我们提取了上临界场${B}_{c2}(T)$。使用低场直流磁化测量来确定低临界场的温度依赖性${B}_{c1}$。从${T}_{c}$到$\ensuremath{\sim}3$ K，观察到${B}_{c1}^{\ensuremath{\perp}}(T)$低于灵敏度极限的特征抑制。
We report on specific-heat, magnetization, and ac-susceptibility measurements of ${\ensuremath{\beta}}^{\ensuremath{''}}\ensuremath{-}(\mathrm{BEDT}\ensuremath{-}\mathrm{TTF}{)}_{2}{\mathrm{SF}}_{5}{\mathrm{CH}}_{2}{\mathrm{CF}}_{2}{\mathrm{SO}}_{3}$, an organic superconductor with ${T}_{c}=4.5$ K, where BEDT-TTF stands for bis(ethylenedithio)-tetrathiafulvalene. The jump of the specific heat $C$ at ${T}_{c}$ and the exact form of the specific-heat difference between $C$ in the superconducting $(B=0$ T) and in the normal $(B=3.5$ T) state can be well described by BCS theory with strong coupling. We estimate an electron-phonon coupling parameter $\ensuremath{\lambda}\ensuremath{\approx}1.1$. From measurements of $C$ in magnetic fields we extract the upper critical field ${B}_{c2}(T)$. Low-field dc-magnetization measurements were used to determine the temperature dependence of the lower critical field ${B}_{c1}$. From ${T}_{c}$ down to $\ensuremath{\sim}3$ K the characteristic suppression of ${B}_{c1}^{\ensuremath{\perp}}(T)$ below the sensitivity limit is observed.