Superconductivity in the ternary germanide La{sub 3}Pd{sub 4}Ge{sub 4}

The ternary germanide La{sub 3}Pd{sub 4}Ge{sub 4} has been prepared by arc melting. This compound takes a body-centered lattice with an orthorhombic unit cell with the lattice parameters of a=4.2200(3) A, b=4.3850(3) A, and c=25.003(2) A. The crystal structure of La{sub 3}Pd{sub 4}Ge{sub 4} is U{sub 3}Ni{sub 4}Si{sub 4}-type with the space group of Immm, consisting of the combination of structural units of AlB{sub 2}-type and BaAl{sub 4}-type layers. This compound is a type-II superconductor with a critical temperature (T{sub c}) of 2.75 K. The lower critical field H{sub c1}(0) is estimated to be 54 Oe. The upper critical field H{sub c2}(0) estimated by linear extrapolation of the H{sub c2}(T) curves is about 4.0 kOe, whereas the Werthamer-Hefland-Hohemberg theory gives H{sub c2}(0){sup WHH}=3.0 kOe. This is an interesting observation of superconductivity in the compounds with U{sub 3}Ni{sub 4}Si{sub 4}-type structure. The coherence length {xi}(0) of 330 A and the penetration depth {lambda}(0) of 2480 A are derived.