Resistivity and thermopower studies on La3X (X≡Al, Sn, In, Ru, Ir, Co, Ni, Ge, Ga) systems

We report resistivity (p) and thermopower (S) measurements on the La3X (X≡Al, Sn, In, Ru, Ir, Co, Ni, Ge, Ga) and La3-x GdxIn (x =0.14, 0.002, 0.06, 0.14, 0.20) systems between 1.7 and 300 K. All the systems except La3Ir and La3-xGdx In (x =0.14, 0.20) become superconducting with Tc below 10 K. The x =0.14 and 0.20 systems order magnetically at 4.7 and 7.1 K respectively. The p curve of all the compounds shows a strong negative curvature at intermediate temperatures followed by its saturation at higher temperatures.