Superconductivity in spinel-type compounds CuRh2S4 and CuRh2Se4

摘要: An extensive study of electrical resistivity, ac magnetic susceptibility, magnetization, specific heat, and NMR has been made on high purity samples the spinel compounds CuRh{sub 2}S{sub 4} 2}Se{sub 4}. The superconducting transitions occur at 4.70 K in 3.48 susceptibilities show perfect diamagnetism both compounds. Upper critical fields {ital T}=0 are estimated to be 20.0 4.40 kOe, lower 70 95 Oe, respectively. thermodynamic 704 Oe (CuRh{sub 4}) 445 4}). These values obtained from temperature dependence free energy. type-II superconductors with Ginzburg-Landau parameters {kappa}=21 {kappa}=6.6 T}=0. electron-phonon coupling constants, {lambda}{sub ep}=0.68 ep}=0.64 4}), using McMillan formula. copper nuclear-spin-relaxation rate as a function shows pronounced coherence peak just below T}{sub c}} for Experimental results analyzed basis BCS theory. exist between weak- intermediate-couplingmore » which driven by interaction. Debye temperatures FTHETA} these materials 230 211 4}).« less