Superconductivity in the ternary germanide La3Pd4Ge4 -: art. no. 214520

The ternary germanide La3Pd4Ge4 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 La3Pd4Ge4 is U3Ni4Si4-type with the space group of Immm, consisting of the combination of structural units of AlB2-type and BaAl4-type layers. This compound is a type-II superconductor with a critical temperature (T-c) of 2.75 K. The lower critical field H-c1(0) is estimated to be 54 Oe. The upper critical field H-c2(0) estimated by linear extrapolation of the H-c2(T) curves is about 4.0 kOe, whereas the Werthamer-Hefland-Hohemberg theory gives H-c2(0)(WHH)=3.0 kOe. This is an interesting observation of superconductivity in the compounds with U3Ni4Si4-type structure. The coherence length xi(0) of 330 A and the penetration depth lambda(0) of 2480 A are derived.