For the first time, the temperature dependences of the electrical resistivity ρ(T) were studied in Gd_xPb_1−xMo₆S₈ (x = 0.5, 0.7, 0.9) compounds in the temperature range 4–18 K and magnetic fields up to 14 T. It is shown that the superconducting transition temperature values T_c decrease from 14.6 K for a compound with x = 0.5 to 11.8 K for x = 0.9. Experimental dependences H_c2(T) were plotted and it was found that the theoretical dependence H_c2(T) within the microscopic theory of Werthamer-Helfand-Hohenberg poorly describes the experimental data for the Gd_0.9Pb_0.1Mo₆S₈ compound. At the same time, the fit of H_c2(T) within the Ginzburg-Landau theory is in good agreement with the experimental results for all the studied samples. An explanation of the dependence H_c2(T) of the studied samples from the gadolinium concentration was proposed. The differential resistance for the Gd_0.5Pb_0.5Mo₆S₈–Ag heterocontact with resistance R_PC ≈ 2.6 Ω was obtained for 2.6 K using point-contact Andreev reflection spectroscopy. As a result, the superconducting gap for Gd_0.5Pb_0.5Mo₆S₈ was estimated for the first time to be Δ ≈ 1.95 meV at 2.6 K. The resulting ratio was 2Δ/kT_c ≈ 3.02, which is lower than the Bardeen–Cooper–Schrieffer value of 3.52 for conventional weakly coupled superconductors.

中文翻译：

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GdxPb1-xMo6S8（x = 0.5，0.7，0.9）化合物的超导性能

首次研究了在 4-18 K温度范围内的Gd _x Pb _{1− x} Mo ₆ S ₈（x = 0.5，0.7，0.9）化合物中电阻率ρ（T）的温度依赖性。最高可达14T。表明超导转变温度值T _c从x  = 0.5的化合物的14.6 K降低到x  = 0.9的化合物的11.8K。绘制了实验相关性H _{c 2}（T），发现理论相关性H _{c 2}（T在Werthamer-Helfand-Hohenberg的微观理论中，T）不能很好地描述Gd _0.9 Pb _0.1 Mo ₆ S ₈化合物的实验数据。同时，H _{c 2}（T）在Ginzburg-Landau理论中的拟合与所有研究样品的实验结果吻合良好。提出了从studied浓度对所研究样品的依赖性H _{c 2}（T）的解释。Gd _0.5 Pb _0.5 Mo ₆ S ₈的差分电阻-Ag异质接触阻力ř _PC  ≈是为2.6说明使用点接触的Andreev反射光谱法获得2.6Ω。其结果是，对于钆的超导能隙_0.5铅_0.5沫₆小号₈估计首次为Δ≈1.95兆电子伏在2.6 K.将所得比2Δ/ KT _Ç  ≈  3.02，其比Bardeen-下传统的弱耦合超导体的Cooper-Schrieffer值为3.52。